Sample records for abaqus user subroutine

  1. Automatic generation of user material subroutines for biomechanical growth analysis.

    PubMed

    Young, Jonathan M; Yao, Jiang; Ramasubramanian, Ashok; Taber, Larry A; Perucchio, Renato

    2010-10-01

    The analysis of the biomechanics of growth and remodeling in soft tissues requires the formulation of specialized pseudoelastic constitutive relations. The nonlinear finite element analysis package ABAQUS allows the user to implement such specialized material responses through the coding of a user material subroutine called UMAT. However, hand coding UMAT subroutines is a challenge even for simple pseudoelastic materials and requires substantial time to debug and test the code. To resolve this issue, we develop an automatic UMAT code generation procedure for pseudoelastic materials using the symbolic mathematics package MATHEMATICA and extend the UMAT generator to include continuum growth. The performance of the automatically coded UMAT is tested by simulating the stress-stretch response of a material defined by a Fung-orthotropic strain energy function, subject to uniaxial stretching, equibiaxial stretching, and simple shear in ABAQUS. The MATHEMATICA UMAT generator is then extended to include continuum growth by adding a growth subroutine to the automatically generated UMAT. The MATHEMATICA UMAT generator correctly derives the variables required in the UMAT code, quickly providing a ready-to-use UMAT. In turn, the UMAT accurately simulates the pseudoelastic response. In order to test the growth UMAT, we simulate the growth-based bending of a bilayered bar with differing fiber directions in a nongrowing passive layer. The anisotropic passive layer, being topologically tied to the growing isotropic layer, causes the bending bar to twist laterally. The results of simulations demonstrate the validity of the automatically coded UMAT, used in both standardized tests of hyperelastic materials and for a biomechanical growth analysis.

  2. Fluid-Structure Interaction Using Retarded Potential and ABAQUS

    DTIC Science & Technology

    1992-08-19

    APPLICATION A retarded potential (RP) capability has been coupled to the ABAQUS program, through the DLOAD user written subroutine , to form ABAQUS - RP...and ABAQUS C. T. DYKA Geo-Centers, Inc. Fort Washington, MD 20744 and M. A. TAMM Computer Operations and Communications Branch Research Computation... ABAQUS 63569N 6. AUTHOR(S) 6604 C. T. Dyka* and M. A. Tamm 7. PERFORMING ORGANIZATION NAME(S) AND AOORESS(ES) b. PERFORMING ORGANIZATION REPORT NUMBER

  3. LAMPAT and LAMPATNL User’s Manual

    DTIC Science & Technology

    2012-09-01

    nonlinearity. These tools are implemented as subroutines in the finite element software ABAQUS . This user’s manual provides information on the proper...model either through the General tab of the Edit Job dialog box in Abaqus /CAE or the command line with user=( subroutine filename). Table 1...Selection of software product and subroutine . Static Analysis With Abaqus /Standard Dynamic Analysis With Abaqus /Explicit Linear, uncoupled

  4. Using ABAQUS Scripting Interface for Materials Evaluation and Life Prediction

    NASA Technical Reports Server (NTRS)

    Powers, Lynn M.; Arnold, Steven M.; Baranski, Andrzej

    2006-01-01

    An ABAQUS script has been written to aid in the evaluation of the mechanical behavior of viscoplastic materials. The purposes of the script are to: handle complex load histories; control load/displacement with alternate stopping criteria; predict failure and life; and verify constitutive models. Material models from the ABAQUS library may be used or the UMAT routine may specify mechanical behavior. User subroutines implemented include: UMAT for the constitutive model; UEXTERNALDB for file manipulation; DISP for boundary conditions; and URDFIL for results processing. Examples presented include load, strain and displacement control tests on a single element model. The tests are creep with a life limiting strain criterion, strain control with a stress limiting cycle and a complex interrupted cyclic relaxation test. The techniques implemented in this paper enable complex load conditions to be solved efficiently with ABAQUS.

  5. Transport Modeling of Hydrogen in Metals for Application to Hydrogen Assisted Cracking of Metals.

    DTIC Science & Technology

    1995-04-04

    34 consists of a Fortran "user element" subroutine for use with the ABAQUS 2 finite element program. Documentation of the 1-D user element subroutine is...trapping theory. The use of the ABAQUS finite element "User Element" subroutines for solving 1-D problems is then outlined in full detail. This is followed...reflect the new ordering given by Eq. (57). ABAOUS User Element Subroutines ABAQUS executes a Fortran subroutine named UEL for each "user defined" finite

  6. Evaluation of a Nonlinear Finite Element Program - ABAQUS.

    DTIC Science & Technology

    1983-03-15

    anisotropic properties. * MATEXP - Linearly elastic thermal expansions with isotropic, orthotropic and anisotropic properties. * MATELG - Linearly...elastic materials for general sections (options available for beam and shell elements). • MATEXG - Linearly elastic thermal expansions for general...decomposition of a matrix. * Q-R algorithm • Vector normalization, etc. Obviously, by consolidating all the utility subroutines in a library, ABAQUS has

  7. Fuselage Versus Subcomponent Panel Response Correlation Based on ABAQUS Explicit Progressive Damage Analysis Tools

    NASA Technical Reports Server (NTRS)

    Gould, Kevin E.; Satyanarayana, Arunkumar; Bogert, Philip B.

    2016-01-01

    Analysis performed in this study substantiates the need for high fidelity vehicle level progressive damage analyses (PDA) structural models for use in the verification and validation of proposed sub-scale structural models and to support required full-scale vehicle level testing. PDA results are presented that capture and correlate the responses of sub-scale 3-stringer and 7-stringer panel models and an idealized 8-ft diameter fuselage model, which provides a vehicle level environment for the 7-stringer sub-scale panel model. Two unique skin-stringer attachment assumptions are considered and correlated in the models analyzed: the TIE constraint interface versus the cohesive element (COH3D8) interface. Evaluating different interfaces allows for assessing a range of predicted damage modes, including delamination and crack propagation responses. Damage models considered in this study are the ABAQUS built-in Hashin procedure and the COmplete STress Reduction (COSTR) damage procedure implemented through a VUMAT user subroutine using the ABAQUS/Explicit code.

  8. An Improved Design Methodology for Modeling Thick-Section Composite Structures Using a Multiscale Approach

    DTIC Science & Technology

    2012-09-01

    Technologies. Helius was developed as a user material subroutine for ABAQUS and ANSYS (9). Through an ABAQUS plug-in and graphical interface, a...incorporated into an ABAQUS subroutine and compared to experimental data. Xie and Biggers (18) look at the effect width-to-hole-diameter ratio on open- hole...smearing-unsmearing” approach, nonlinear anisotropy, and progressive failure analysis into ABAQUS . The subroutine UMAT is used to define the

  9. Application of MCT Failure Criterion using EFM

    DTIC Science & Technology

    2010-03-26

    because HELIUS:MCT™ does not facilitate this. Attempts have been made to use ABAQUS native thermal expansion model combined in addition to Helius-MCT... ABAQUS using a user defined element subroutine EFM. Comparisons have been made between the analysis results using EFM-MCT code and HELIUS:MCT™ code...using the Element-Failure Method (EFM) in ABAQUS . The EFM-MCT has been implemented in ABAQUS using a user defined element subroutine EFM. Comparisons

  10. SPECabq v. 2.0

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chambers, Robert S.; Neidigk, Matthew A.

    Sandia SPECabq is FORTRAN code that defines the user supplied subroutines needed to perform nonlinear viscoelastic analyses in the ABAQUS commercial finite element code based on the Simplified Potential Energy Clock (SPEC) Model. The SPEC model was published in the open literature in 2009. It must be compiled and linked with the ABAQUS libraries under the user supplied subroutine option of the ABAQUS executable script. The subroutine is used to analyze the thermomechanical behavior of isotropic polymers predicting things like how a polymer may undergo stress or volume relaxation under different temperature and loading environments. This subroutine enables the ABAQUSmore » finite element code to be used for analyzing the thermo-mechanical behavior of samples and parts that are made from glassy polymers.« less

  11. A parameter estimation subroutine package

    NASA Technical Reports Server (NTRS)

    Bierman, G. J.; Nead, M. W.

    1978-01-01

    Linear least squares estimation and regression analyses continue to play a major role in orbit determination and related areas. In this report we document a library of FORTRAN subroutines that have been developed to facilitate analyses of a variety of estimation problems. Our purpose is to present an easy to use, multi-purpose set of algorithms that are reasonably efficient and which use a minimal amount of computer storage. Subroutine inputs, outputs, usage and listings are given along with examples of how these routines can be used. The following outline indicates the scope of this report: Section (1) introduction with reference to background material; Section (2) examples and applications; Section (3) subroutine directory summary; Section (4) the subroutine directory user description with input, output, and usage explained; and Section (5) subroutine FORTRAN listings. The routines are compact and efficient and are far superior to the normal equation and Kalman filter data processing algorithms that are often used for least squares analyses.

  12. Thermal and flow analysis subroutines for the SINDA-version 9 computer routine

    NASA Technical Reports Server (NTRS)

    Oren, J. A.; Williams, D. R.

    1973-01-01

    Fluid flow analysis, special thermal analysis and input/output capabilities of the MOTAR routine were incorporated into the SINDA routine. All the capabilities were added in the form of user subroutines so that they may be added to different versions of SINDA with a minimum of programmer effort. Two modifications were made to the existing subroutines of SINDA/8 to incorporate the above subroutines. These were: (1) A modification to the preprocessor to permit actual values of array numbers, conductor numbers, node numbers or constant numbers supplied as array data to be converted to relative numbers. (2) Modifications to execution subroutine CNFAST to make it compatible with the radiant interchange user subroutine, RADIR. This modified version of SINDA has been designated SINDA/version 9. A detailed discussion of the methods used for the capabilities added is presented. The modifications for the SINDA subroutines are described, as well as user subroutines. All subroutines added or modified are listed.

  13. Nanoscale Transport Optimization

    DTIC Science & Technology

    2008-12-04

    could be argued that the advantage of using ABAQUS for this modeling construct has more to do with its ability to impose a user-defined subroutine that...finite element analysis. This is accomplished by employing a user defined subroutine for fluid properties at the interface within the finite element...package ABAQUS . Model Components: As noted above the governing equation for the material system is given as, ( ) ( ) 4484476444 8444 76

  14. Input Files and Procedures for Analysis of SMA Hybrid Composite Beams in MSC.Nastran and ABAQUS

    NASA Technical Reports Server (NTRS)

    Turner, Travis L.; Patel, Hemant D.

    2005-01-01

    A thermoelastic constitutive model for shape memory alloys (SMAs) and SMA hybrid composites (SMAHCs) was recently implemented in the commercial codes MSC.Nastran and ABAQUS. The model is implemented and supported within the core of the commercial codes, so no user subroutines or external calculations are necessary. The model and resulting structural analysis has been previously demonstrated and experimentally verified for thermoelastic, vibration and acoustic, and structural shape control applications. The commercial implementations are described in related documents cited in the references, where various results are also shown that validate the commercial implementations relative to a research code. This paper is a companion to those documents in that it provides additional detail on the actual input files and solution procedures and serves as a repository for ASCII text versions of the input files necessary for duplication of the available results.

  15. Review of Soil Models and Their Implementation in Multibody System Algorithms

    DTIC Science & Technology

    2012-02-01

    models for use with ABAQUS . The constitutive models of the user defined materials can be programmed in the user subroutine UMAT. Many user defined...mechanical characteristics of mildly or moderately expansive unsaturated soils. As originally proposed by Alonso, utilizing a critical state framework...review of some of these programs is presented. ABAQUS ABAQUS is a popular FE analysis program that contains a wide variety of material models and

  16. Mach 14 Flow Restrictor Thermal Stress Analysis

    DTIC Science & Technology

    1984-08-01

    tranfer analysis, thermal stress analysis, results translation from ABAQUS to PATRAN-G, and the method used to determine the heat transfer film...G, model translation into ABAQUS format, transient heat transfer analysis and thermal stress analysis input decks, results translation from ABAQUS ...TRANSLATION FROM PATRAN-G TO ABAQUS 3 ABAQUS CONSIDERATIONS 8 MATERIAL PROPERTIES OF COLUMBIUM C-103 10 USER SUBROUTINE FILM 11 TRANSIENT

  17. Structural Technology Evaluation and Analysis Program (STEAP). Delivery Order 0046: Multiscale Modeling of Composite Structures Subjected to Cyclic Loading

    DTIC Science & Technology

    2012-09-01

    on transformation field analysis [19], proper orthogonal decomposition [63], eigenstrains [23], and others [1, 29, 39] have brought significant...commercial finite element software (Abaqus) along with the user material subroutine utility ( UMAT ) is employed to solve these problems. In this section...Symmetric Coefficients TFA: Transformation Field Analysis UMAT : User Material Subroutine

  18. Rational-Spline Subroutines

    NASA Technical Reports Server (NTRS)

    Schiess, James R.; Kerr, Patricia A.; Smith, Olivia C.

    1988-01-01

    Smooth curves drawn among plotted data easily. Rational-Spline Approximation with Automatic Tension Adjustment algorithm leads to flexible, smooth representation of experimental data. "Tension" denotes mathematical analog of mechanical tension in spline or other mechanical curve-fitting tool, and "spline" as denotes mathematical generalization of tool. Program differs from usual spline under tension, allows user to specify different values of tension between adjacent pairs of knots rather than constant tension over entire range of data. Subroutines use automatic adjustment scheme that varies tension parameter for each interval until maximum deviation of spline from line joining knots less than or equal to amount specified by user. Procedure frees user from drudgery of adjusting individual tension parameters while still giving control over local behavior of spline.

  19. Micromechanics-Based Structural Analysis (FEAMAC) and Multiscale Visualization within Abaqus/CAE Environment

    NASA Technical Reports Server (NTRS)

    Arnold, Steven M.; Bednarcyk, Brett A.; Hussain, Aquila; Katiyar, Vivek

    2010-01-01

    A unified framework is presented that enables coupled multiscale analysis of composite structures and associated graphical pre- and postprocessing within the Abaqus/CAE environment. The recently developed, free, Finite Element Analysis--Micromechanics Analysis Code (FEAMAC) software couples NASA's Micromechanics Analysis Code with Generalized Method of Cells (MAC/GMC) with Abaqus/Standard and Abaqus/Explicit to perform micromechanics based FEA such that the nonlinear composite material response at each integration point is modeled at each increment by MAC/GMC. The Graphical User Interfaces (FEAMAC-Pre and FEAMAC-Post), developed through collaboration between SIMULIA Erie and the NASA Glenn Research Center, enable users to employ a new FEAMAC module within Abaqus/CAE that provides access to the composite microscale. FEA IAC-Pre is used to define and store constituent material properties, set-up and store composite repeating unit cells, and assign composite materials as sections with all data being stored within the CAE database. Likewise FEAMAC-Post enables multiscale field quantity visualization (contour plots, X-Y plots), with point and click access to the microscale i.e., fiber and matrix fields).

  20. Reliability of Next Generation Power Electronics Packaging Under Concurrent Vibration, Thermal and High Power Loads

    DTIC Science & Technology

    2008-02-01

    combined thermal g effect and initial current field. The model is implemented using Abaqus user element subroutine and verified against the experimental...Finite Element Formulation The proposed model is implemented with ABAQUS general purpose finite element program using thermal -displacement analysis...option. ABAQUS and other commercially available finite element codes do not have the capability to solve general electromigration problem directly. Thermal

  1. Spectrally formulated user-defined element in Abaqus for wave motion analysis and health monitoring of composite structures

    NASA Astrophysics Data System (ADS)

    Khalili, Ashkan

    Wave propagation analysis in 1-D and 2-D composite structures is performed efficiently and accurately through the formulation of a User-Defined Element (UEL) based on the wavelet spectral finite element (WSFE) method. The WSFE method is based on the first order shear deformation theory which yields accurate results for wave motion at high frequencies. The wave equations are reduced to ordinary differential equations using Daubechies compactly supported, orthonormal, wavelet scaling functions for approximations in time and one spatial dimension. The 1-D and 2-D WSFE models are highly efficient computationally and provide a direct relationship between system input and output in the frequency domain. The UEL is formulated and implemented in Abaqus for wave propagation analysis in composite structures with complexities. Frequency domain formulation of WSFE leads to complex valued parameters, which are decoupled into real and imaginary parts and presented to Abaqus as real values. The final solution is obtained by forming a complex value using the real number solutions given by Abaqus. Several numerical examples are presented here for 1-D and 2-D composite waveguides. Wave motions predicted by the developed UEL correlate very well with Abaqus simulations using shear flexible elements. The results also show that the UEL largely retains computational efficiency of the WSFE method and extends its ability to model complex features. An enhanced cross-correlation method (ECCM) is developed in order to accurately predict damage location in plates. Three major modifications are proposed to the widely used cross-correlation method (CCM) to improve damage localization capabilities, namely actuator-sensor configuration, signal pre-processing method, and signal post-processing method. The ECCM is investigated numerically (FEM simulation) and experimentally. Experimental investigations for damage detection employ a PZT transducer as actuator and laser Doppler vibrometer as sensor

  2. Impact of Truck Loading on Design and Analysis of Asphaltic Pavement Structures : Phase II

    DOT National Transportation Integrated Search

    2011-02-01

    In this study, Schaperys nonlinear viscoelastic constitutive model is implemented into the commercial finite element (FE) software ABAQUS via user defined subroutine (user material, or UMAT) to analyze asphalt pavement subjected to heavy truck loa...

  3. ParaView visualization of Abaqus output on the mechanical deformation of complex microstructures

    NASA Astrophysics Data System (ADS)

    Liu, Qingbin; Li, Jiang; Liu, Jie

    2017-02-01

    Abaqus® is a popular software suite for finite element analysis. It delivers linear and nonlinear analyses of mechanical and fluid dynamics, includes multi-body system and multi-physics coupling. However, the visualization capability of Abaqus using its CAE module is limited. Models from microtomography have extremely complicated structures, and datasets of Abaqus output are huge, requiring a visualization tool more powerful than Abaqus/CAE. We convert Abaqus output into the XML-based VTK format by developing a Python script and then using ParaView to visualize the results. Such capabilities as volume rendering, tensor glyphs, superior animation and other filters allow ParaView to offer excellent visualizing manifestations. ParaView's parallel visualization makes it possible to visualize very big data. To support full parallel visualization, the Python script achieves data partitioning by reorganizing all nodes, elements and the corresponding results on those nodes and elements. The data partition scheme minimizes data redundancy and works efficiently. Given its good readability and extendibility, the script can be extended to the processing of more different problems in Abaqus. We share the script with Abaqus users on GitHub.

  4. Algorithm-Based Fault Tolerance for Numerical Subroutines

    NASA Technical Reports Server (NTRS)

    Tumon, Michael; Granat, Robert; Lou, John

    2007-01-01

    A software library implements a new methodology of detecting faults in numerical subroutines, thus enabling application programs that contain the subroutines to recover transparently from single-event upsets. The software library in question is fault-detecting middleware that is wrapped around the numericalsubroutines. Conventional serial versions (based on LAPACK and FFTW) and a parallel version (based on ScaLAPACK) exist. The source code of the application program that contains the numerical subroutines is not modified, and the middleware is transparent to the user. The methodology used is a type of algorithm- based fault tolerance (ABFT). In ABFT, a checksum is computed before a computation and compared with the checksum of the computational result; an error is declared if the difference between the checksums exceeds some threshold. Novel normalization methods are used in the checksum comparison to ensure correct fault detections independent of algorithm inputs. In tests of this software reported in the peer-reviewed literature, this library was shown to enable detection of 99.9 percent of significant faults while generating no false alarms.

  5. SMAUMAT_ITI

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jannetti, C.; Becker, R.

    The software is an ABAQUS/Standard UMAT (user defined material behavior subroutine) that implements the constitutive model for shape-memory alloy materials developed by Jannetti et. al. (2003a) using a fully implicit time integration scheme to integrate the constitutive equations. The UMAT is used in conjunction with ABAQUS/Standard to perform a finite-element analysis of SMA materials.

  6. RATIONAL SPLINE SUBROUTINES

    NASA Technical Reports Server (NTRS)

    Schiess, J. R.

    1994-01-01

    Scientific data often contains random errors that make plotting and curve-fitting difficult. The Rational-Spline Approximation with Automatic Tension Adjustment algorithm lead to a flexible, smooth representation of experimental data. The user sets the conditions for each consecutive pair of knots:(knots are user-defined divisions in the data set) to apply no tension; to apply fixed tension; or to determine tension with a tension adjustment algorithm. The user also selects the number of knots, the knot abscissas, and the allowed maximum deviations from line segments. The selection of these quantities depends on the actual data and on the requirements of a particular application. This program differs from the usual spline under tension in that it allows the user to specify different tension values between each adjacent pair of knots rather than a constant tension over the entire data range. The subroutines use an automatic adjustment scheme that varies the tension parameter for each interval until the maximum deviation of the spline from the line joining the knots is less than or equal to a user-specified amount. This procedure frees the user from the drudgery of adjusting individual tension parameters while still giving control over the local behavior of the spline The Rational Spline program was written completely in FORTRAN for implementation on a CYBER 850 operating under NOS. It has a central memory requirement of approximately 1500 words. The program was released in 1988.

  7. Factors Affecting Energy Absorption of a Plate during Shock Wave Impact Using a Damage Material Model

    DTIC Science & Technology

    2010-08-07

    51 5.3.2 Abaqus VDLOAD Subroutine ............................................. 55 VI. INTERPRETATION OF RESULTS AND DISCUSSION...VDLOAD SUBROUTINE ........................................................... 91 C. PYTHON SCRIPT TO CONVERT ABAQUS INPUT FILE TO LS-DYNA INPUT FILE...all of the simulations, which are the pressures applied from the Abaqus /Explicit VDLOAD subroutine . The entire model 22 including the boundary

  8. Investigation of the Constitutive Model Used in Nonlinear, Incremental Structural Analyses.

    DTIC Science & Technology

    1998-06-01

    package, ABAQUS , was chosen for performing NISA studies in part because user supplied subroutines could be used for constitutive relationships. After a...loading and the shrinkage and thermally induced strains determined from control specimens. The majority of creep tests are uniaxial compressive tests...Kennedy, and Perry (1970). Description of FE Model The tests were simulated using the finite element (FE) program ABAQUS and the aging viscoelastic

  9. NSWC Library of Mathematics Subroutines

    DTIC Science & Technology

    1990-01-01

    sufficiently many zero elements for it to be worthwhile to use special techniques that avoid storing and operating with the zeros.U The scheme adopted by the... general purpose numerical mathematics subroutines began. The subroutines are written in ANSI standard Fortran. This manual describes the subroutines in...PLCOPYDPCOPY ............ ...................... 113 Addition of Polynomials - PADD ,DPADD ............. .................. I.... 115 Subtraction of

  10. Nonlinear, Incremental Structural Analysis of Olmsted Locks and Dams. Volume 1: Main Text

    DTIC Science & Technology

    1992-12-01

    dependent functions, which are supplied as algebraic functions of time or as data arrays in ABAQUS user subroutines (Hibbitt, Karlsson, and Sorenson 1988...143.0 Thermal Prouerties 9. The heat transfer capability of ABAQUS uses the finite element method to numerically solve the governing differential...coefficient of linear thermal expansion which were conducted at WES for Olmsted mixtures 6 and 11 (Hammons et al. 1991). The different concrete mixture

  11. Proceedings of the U.S. Army Symposium on Gun Dynamics (5th) Held in Rensselaerville, New York on 23-25 September 1987

    DTIC Science & Technology

    1987-09-01

    have shown that gun barrel heating, and hence thermal expansion , is both axially and circumferentially asymmetric. Circumferential, or cross-barrel...element code, which ended in the selection of ABAQUS . The code will perform static, dynamic, and thermal anal- ysis on a broad range of structures...analysis may be performed by a user supplied FORTRAN subroutine which is automatically linked to the code and supplements the stand- ard ABAQUS

  12. Abaqus Simulations of Rock Response to Dynamic Loading

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Steedman, David W.; Coblentz, David

    The LANL Geodynamics Team has been applying Abaqus modeling to achieve increasingly complex simulations. Advancements in Abaqus model building and simulation tools allows this progress. We use Lab-developed constitutive models, the fully coupled CEL Abaqus and general contact to simulate response of realistic sites to explosively driven shock.

  13. Development of a Pressure-Dependent Constitutive Model with Combined Multilinear Kinematic and Isotropic Hardening

    NASA Technical Reports Server (NTRS)

    Allen Phillip A.; Wilson, Christopher D.

    2003-01-01

    The development of a pressure-dependent constitutive model with combined multilinear kinematic and isotropic hardening is presented. The constitutive model is developed using the ABAQUS user material subroutine (UMAT). First the pressure-dependent plasticity model is derived. Following this, the combined bilinear and combined multilinear hardening equations are developed for von Mises plasticity theory. The hardening rule equations are then modified to include pressure dependency. The method for implementing the new constitutive model into ABAQUS is given.

  14. An open source software tool to assign the material properties of bone for ABAQUS finite element simulations.

    PubMed

    Pegg, Elise C; Gill, Harinderjit S

    2016-09-06

    A new software tool to assign the material properties of bone to an ABAQUS finite element mesh was created and compared with Bonemat, a similar tool originally designed to work with Ansys finite element models. Our software tool (py_bonemat_abaqus) was written in Python, which is the chosen scripting language for ABAQUS. The purpose of this study was to compare the software packages in terms of the material assignment calculation and processing speed. Three element types were compared (linear hexahedral (C3D8), linear tetrahedral (C3D4) and quadratic tetrahedral elements (C3D10)), both individually and as part of a mesh. Comparisons were made using a CT scan of a hemi-pelvis as a test case. A small difference, of -0.05kPa on average, was found between Bonemat version 3.1 (the current version) and our Python package. Errors were found in the previous release of Bonemat (version 3.0 downloaded from www.biomedtown.org) during calculation of the quadratic tetrahedron Jacobian, and conversion of the apparent density to modulus when integrating over the Young׳s modulus field. These issues caused up to 2GPa error in the modulus assignment. For these reasons, we recommend users upgrade to the most recent release of Bonemat. Processing speeds were assessed for the three different element types. Our Python package took significantly longer (110s on average) to perform the calculations compared with the Bonemat software (10s). Nevertheless, the workflow advantages of the package and added functionality makes 'py_bonemat_abaqus' a useful tool for ABAQUS users. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. A parameter estimation subroutine package

    NASA Technical Reports Server (NTRS)

    Bierman, G. J.; Nead, W. M.

    1977-01-01

    Linear least squares estimation and regression analyses continue to play a major role in orbit determination and related areas. FORTRAN subroutines have been developed to facilitate analyses of a variety of parameter estimation problems. Easy to use multipurpose sets of algorithms are reported that are reasonably efficient and which use a minimal amount of computer storage. Subroutine inputs, outputs, usage and listings are given, along with examples of how these routines can be used.

  16. Attitude dynamics simulation subroutines for systems of hinge-connected rigid bodies

    NASA Technical Reports Server (NTRS)

    Fleischer, G. E.; Likins, P. W.

    1974-01-01

    Several computer subroutines are designed to provide the solution to minimum-dimension sets of discrete-coordinate equations of motion for systems consisting of an arbitrary number of hinge-connected rigid bodies assembled in a tree topology. In particular, these routines may be applied to: (1) the case of completely unrestricted hinge rotations, (2) the totally linearized case (all system rotations are small), and (3) the mixed, or partially linearized, case. The use of the programs in each case is demonstrated using a five-body spacecraft and attitude control system configuration. The ability of the subroutines to accommodate prescribed motions of system bodies is also demonstrated. Complete listings and user instructions are included for these routines (written in FORTRAN V) which are intended as multi- and general-purpose tools in the simulation of spacecraft and other complex electromechanical systems.

  17. AMPHION: Specification-based programming for scientific subroutine libraries

    NASA Technical Reports Server (NTRS)

    Lowry, Michael; Philpot, Andrew; Pressburger, Thomas; Underwood, Ian; Waldinger, Richard; Stickel, Mark

    1994-01-01

    AMPHION is a knowledge-based software engineering (KBSE) system that guides a user in developing a diagram representing a formal problem specification. It then automatically implements a solution to this specification as a program consisting of calls to subroutines from a library. The diagram provides an intuitive domain oriented notation for creating a specification that also facilitates reuse and modification. AMPHION'S architecture is domain independent. AMPHION is specialized to an application domain by developing a declarative domain theory. Creating a domain theory is an iterative process that currently requires the joint expertise of domain experts and experts in automated formal methods for software development.

  18. Comparison between FEBio and Abaqus for biphasic contact problems.

    PubMed

    Meng, Qingen; Jin, Zhongmin; Fisher, John; Wilcox, Ruth

    2013-09-01

    Articular cartilage plays an important role in the function of diarthrodial joints. Computational methods have been used to study the biphasic mechanics of cartilage, and Abaqus has been one of the most widely used commercial software packages for this purpose. A newly developed open-source finite element solver, FEBio, has been developed specifically for biomechanical applications. The aim of this study was to undertake a direct comparison between FEBio and Abaqus for some practical contact problems involving cartilage. Three model types, representing a porous flat-ended indentation test, a spherical-ended indentation test, and a conceptual natural joint contact model, were compared. In addition, a parameter sensitivity study was also performed for the spherical-ended indentation test to investigate the effects of changes in the input material properties on the model outputs, using both FEBio and Abaqus. Excellent agreement was found between FEBio and Abaqus for all of the model types and across the range of material properties that were investigated.

  19. Comparison between FEBio and Abaqus for biphasic contact problems

    PubMed Central

    Jin, Zhongmin; Fisher, John; Wilcox, Ruth

    2013-01-01

    Articular cartilage plays an important role in the function of diarthrodial joints. Computational methods have been used to study the biphasic mechanics of cartilage, and Abaqus has been one of the most widely used commercial software packages for this purpose. A newly developed open-source finite element solver, FEBio, has been developed specifically for biomechanical applications. The aim of this study was to undertake a direct comparison between FEBio and Abaqus for some practical contact problems involving cartilage. Three model types, representing a porous flat-ended indentation test, a spherical-ended indentation test, and a conceptual natural joint contact model, were compared. In addition, a parameter sensitivity study was also performed for the spherical-ended indentation test to investigate the effects of changes in the input material properties on the model outputs, using both FEBio and Abaqus. Excellent agreement was found between FEBio and Abaqus for all of the model types and across the range of material properties that were investigated. PMID:23804955

  20. FY07 NRL DoD High Performance Computing Modernization Program Annual Reports

    DTIC Science & Technology

    2008-09-05

    performed. Implicit and explicit solutions methods are used as appropriate. The primary finite element codes used are ABAQUS and ANSYS. User subroutines ...geometric complexities, loading path dependence, rate dependence, and interaction between loading types (electrical, thermal and mechanical). Work is not...are used for specialized material constitutive response. Coupled material responses, such as electrical- thermal for capacitor materials or electrical

  1. A parameter estimation subroutine package

    NASA Technical Reports Server (NTRS)

    Bierman, G. J.; Nead, M. W.

    1978-01-01

    Linear least squares estimation and regression analyses continue to play a major role in orbit determination and related areas. A library of FORTRAN subroutines were developed to facilitate analyses of a variety of estimation problems. An easy to use, multi-purpose set of algorithms that are reasonably efficient and which use a minimal amount of computer storage are presented. Subroutine inputs, outputs, usage and listings are given, along with examples of how these routines can be used. The routines are compact and efficient and are far superior to the normal equation and Kalman filter data processing algorithms that are often used for least squares analyses.

  2. User-Defined Material Model for Progressive Failure Analysis

    NASA Technical Reports Server (NTRS)

    Knight, Norman F. Jr.; Reeder, James R. (Technical Monitor)

    2006-01-01

    An overview of different types of composite material system architectures and a brief review of progressive failure material modeling methods used for structural analysis including failure initiation and material degradation are presented. Different failure initiation criteria and material degradation models are described that define progressive failure formulations. These progressive failure formulations are implemented in a user-defined material model (or UMAT) for use with the ABAQUS/Standard1 nonlinear finite element analysis tool. The failure initiation criteria include the maximum stress criteria, maximum strain criteria, the Tsai-Wu failure polynomial, and the Hashin criteria. The material degradation model is based on the ply-discounting approach where the local material constitutive coefficients are degraded. Applications and extensions of the progressive failure analysis material model address two-dimensional plate and shell finite elements and three-dimensional solid finite elements. Implementation details and use of the UMAT subroutine are described in the present paper. Parametric studies for composite structures are discussed to illustrate the features of the progressive failure modeling methods that have been implemented.

  3. Comparison of Damage Path Predictions for Composite Laminates by Explicit and Standard Finite Element Analysis Tools

    NASA Technical Reports Server (NTRS)

    Bogert, Philip B.; Satyanarayana, Arunkumar; Chunchu, Prasad B.

    2006-01-01

    Splitting, ultimate failure load and the damage path in center notched composite specimens subjected to in-plane tension loading are predicted using progressive failure analysis methodology. A 2-D Hashin-Rotem failure criterion is used in determining intra-laminar fiber and matrix failures. This progressive failure methodology has been implemented in the Abaqus/Explicit and Abaqus/Standard finite element codes through user written subroutines "VUMAT" and "USDFLD" respectively. A 2-D finite element model is used for predicting the intra-laminar damages. Analysis results obtained from the Abaqus/Explicit and Abaqus/Standard code show good agreement with experimental results. The importance of modeling delamination in progressive failure analysis methodology is recognized for future studies. The use of an explicit integration dynamics code for simple specimen geometry and static loading establishes a foundation for future analyses where complex loading and nonlinear dynamic interactions of damage and structure will necessitate it.

  4. Red River Waterway Thermal Studies. Report 2. Thermal Stress Analyses

    DTIC Science & Technology

    1991-12-01

    stress relaxation, q. Shrinkage of the concrete, and . Thermal properties of the concrete including coefficient of thermal expansion , specific heat...Finite-Element Code 12. The thermal stress analyses in this investigation was performed using ABAQUS , a general-purpose, heat-transfer and structural...model (the UMAT 9 subroutine discussed below) may be incorporated as an external subroutine linked to the ABAQUS library. 14. In order to model the

  5. Grow--a computer subroutine that projects the growth of trees in the Lake States' forests.

    Treesearch

    Gary J. Brand

    1981-01-01

    A computer subroutine, Grow, has been written in 1977 Standard FORTRAN to implement a distance-independent, individual tree growth model for Lake States' forests. Grow is a small and easy-to-use version of the growth model. All the user has to do is write a calling program to read initial conditions, call Grow, and summarize the results.

  6. Molecular- and Domain-level Microstructure-dependent Material Model for Nano-segregated Polyurea

    DTIC Science & Technology

    2013-04-15

    material subroutine VUMAT of ABAQUS /Explicit (Dassault Systems, 2010), a commercial finite element code. This subroutine is called by the ABAQUS solver...rate of change of the local internal thermal energy is equal to the corresponding rate of dissipative work. Critical assessment of this model identified...The model also takes into account the plastic expansion or contraction of voids and therefore the stresses are appropriately modified to account for

  7. Effects of Injected CO2 on Geomechanical Properties Due to Mineralogical Changes

    NASA Astrophysics Data System (ADS)

    Nguyen, B. N.; Hou, Z.; Bacon, D. H.; Murray, C. J.; White, J. A.

    2013-12-01

    Long-term injection and storage of CO2 in deep underground reservoirs may significantly modify the geomechanical behavior of rocks since CO2 can react with the constituent phases of reservoir rocks and modify their composition. This can lead to modifications of their geomechanical properties (i.e., elastic moduli, Biot's coefficients, and permeability). Modifications of rock geomechanical properties have important consequences as these directly control stress and strain distributions, affect conditions for fracture initiation and development and/or fault healing. This paper attempts to elucidate the geochemical effects of CO2 on geomechanical properties of typical reservoir rocks by means of numerical analyses using the STOMP-ABAQUS sequentially coupled simulator that includes the capability to handle geomechanics and the reactive transport of CO2 together with a module (EMTA) to compute the homogenized rock poroelastic properties as a function of composition changes. EMTA, a software module developed at PNNL, implements the standard and advanced Eshelby-Mori-Tanaka approaches to compute the thermoelastic properties of composite materials. In this work, EMTA will be implemented in the coupled STOMP-ABAQUS simulator as a user subroutine of ABAQUS and used to compute local elastic stiffness based on rock composition. Under the STOMP-ABAQUS approach, STOMP models are built to simulate aqueous and CO2 multiphase fluid flows, and relevant chemical reactions of pore fluids with minerals in the reservoirs. The ABAQUS models then read STOMP output data for cell center coordinates, gas pressures, aqueous pressures, temperatures, saturations, constituent volume fractions, as well as permeability and porosity that are affected by chemical reactions. These data are imported into ABAQUS meshes using a mapping procedure developed for the exchange of data between STOMP and ABAQUS. Constitutive models implemented in ABAQUS via user subroutines then compute stiffness, stresses

  8. Numerical Modeling of S-Wave Generation by Fracture Damage in Underground Nuclear Explosions

    DTIC Science & Technology

    2009-09-30

    Element Package, ABAQUS. A user -defined subroutine , VUMAT, was written that incorporates the micro-mechanics based damage constitutive law described...dynamic damage evolution on the elastic and anelastic response. 2) whereas the Ashby/Sammis model was only applicable to the case where the initial cracks ...are all parallel and the same size, we can now include a specified distribution of initial crack sizes with random azimuthal orientation about the

  9. Progressive Failure Analysis of Advanced Composites

    DTIC Science & Technology

    2008-07-25

    Fracture angle. αii Coefficients of thermal expansion . βii Coefficients of hygroscopic expansion . β Shear response factor. ηL Coefficient of... thermal expansion in the longitudinal and transverse direc- tions. To enable the calculation of the thermal stresses, the user should define in the...development of this second VUMAT subroutine was planned for the second year of this project). 4.2 Input into Abaqus explicit 4.2.1 Shell elements

  10. Midwest Structural Sciences Center 2009 Annual Report

    DTIC Science & Technology

    2010-08-01

    simulations. Numerical simulations were carried with a single edge notch beam using an ABAQUS user-element subroutine in conjunction with bilinear and...this effort Digital Image Correlation (DIC) has been applied to measure the coefficient of thermal expansion of the nickel-based super alloy...between 30 and 650°C, the thermal expansion coefficient of Hastelloy X was measured over this entire range and found to be in good agreement with

  11. Modeling Plasticity of Ni3Al-Based L12 Intermetallic Single Crystals-I. Anomalous Temperature Dependence of the Flow Behavior (Preprint)

    DTIC Science & Technology

    2006-07-01

    dislocation-loop expansion . The new model was used to simulate the thermally reversible flow behaviour for C-S type two-step deformation, and the results are...implemented into the finite element software ABAQUS through a User MATerial subroutine (UMAT). A tangent modulus method [48] was used for the time...locking under a dislocation loop- expansion configuration. This approach was motivated by modern understanding of dislocation mechanisms for Ni3Al

  12. Computational Investigation of Structured Shocks in Al/SiC-Particulate Metal-Matrix Composites

    DTIC Science & Technology

    2011-06-01

    used to implement the dynamic-mixture model into the VUMAT user-material subroutine of ABAQUS /Explicit. Owing to the attendant large strains and...that the residual thermal - expansion effects are more pronounced in the aluminium-matrix than in SiC-particulates. This finding is consistent with the...simple waves (CSWs) (Davison, 2008). . In accordance with the previously observed larger thermal - expansion effects in Al, Figure 5(b) shows that the

  13. Multiscale Modeling and Multifunctional Composites

    DTIC Science & Technology

    2013-07-17

    dλ α µ α= − − = +E Eθ θ (9) 6 where α is the coefficient of thermal expansion , and ,e d...longitudinal and transverse coefficient of thermal expansion , respectively. The piezoelectric constants are related by (Bahei-El-Din, 2009) 31 31 33 33 31...is coded into the user defined subroutine UEXPAN of the ABAQUS finite element program. This serves as the interface between the global finite element

  14. Frontiers in Anisotropic Shock-Wave Modeling

    DTIC Science & Technology

    2012-02-01

    Nowadays, some models incorporate a user-defined subroutine within the commercial software (e.g., ABAQUS ) to take into account either a homogenous...and temperature on the mass density. The specific internal energy can be decomposed into potentials describing the cold compression, ec (ρ, S); thermal ...Taylor’s series expansion of the Hugoniot pressure P . Assume that the linear approximation between the shock velocity US 24 and particle velocity up

  15. RT11LIB: a library of subroutines for transferring data between a PDP-11 and CDC-6600

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jones, H.D.

    1978-01-01

    RT11LIB is a library of subroutines available to CDC 6600 users for the purpose of transferring data or program listings between a PDP-11 and a CDC 6600. These subroutines, operating on a CDC 6600 under the NOS/BE or SCOPE 3.4 operating systems, read or write magnetic tapes that are compatible with the PDP-11's RT11 operating system. Data written on the tape by the PDP-11 can be read by these subroutines and then translated into CDC 6600 format for subsequent data analysis. The translation process provides for many data formats, including byte, integer, floating point, and character string formats. Alternatively, datamore » from the CDC 6600 can be translated into PDP-11 format then written onto the tape for subsequent use on the PDP-11. This facility allows a program punched on a card deck by a keypunch operator to be transferred to the PDP-11, even though the PDP-11 is not itself equipped with a card reader.« less

  16. Universal Noiseless Coding Subroutines

    NASA Technical Reports Server (NTRS)

    Schlutsmeyer, A. P.; Rice, R. F.

    1986-01-01

    Software package consists of FORTRAN subroutines that perform universal noiseless coding and decoding of integer and binary data strings. Purpose of this type of coding to achieve data compression in sense that coded data represents original data perfectly (noiselessly) while taking fewer bits to do so. Routines universal because they apply to virtually any "real-world" data source.

  17. Basic Scientific Subroutines, Volume II.

    ERIC Educational Resources Information Center

    Ruckdeschel, F. R.

    This book, second in a series dealing with scientific programing in the BASIC language, provides students, engineers, and scientists with a documented library of subroutines for scientific applications. Subjects of the eight chapters include: (1) least-squares approximation of functions and smoothing of data; (2) approximating functions by series…

  18. Numerical Simulation of Wear in a C/C Composite Multidisk Clutch (Preprint)

    DTIC Science & Technology

    2009-04-01

    subroutine FRIC, in the commercial finite element software ( ABAQUS , 6.5-1, Pawtucket, RI) [25], to calculate the local wear depth increment (decrease in...temperature continuity and the heat balance conditions must be satisfied. The subroutine FRIC in ABAQUS code [25] is called only when the contact point is...0.33, thermal expansion coefficients αr = 0.31x10-6/K, αz = 0.29x10-6/K, friction coefficient µ = 0.20, heat convection coefficient h = 100 W/m2K

  19. A Combined Experimental and Numerical Technique to Estimate Interfacial Bond Strength in MMC-Encapsulated Ceramic Systems

    DTIC Science & Technology

    2013-03-01

    with density, Young’s modulus, coefficient of thermal expansion , and Poisson’s ratio, of 3.2 cm 3 , 449 GPa, 4.0 × 10 –6 o C –1 , and 0.16...considers the effect of hydrostatic pressure (confinement) on the strength of ceramics and was implemented using a user subroutine in ABAQUS . The...Due to the high temperature of the encapsulation casting process and the large differential in coefficients of thermal expansion (CTE) between the MMC

  20. Hypercluster parallel processing library user's manual

    NASA Technical Reports Server (NTRS)

    Quealy, Angela

    1990-01-01

    This User's Manual describes the Hypercluster Parallel Processing Library, composed of FORTRAN-callable subroutines which enable a FORTRAN programmer to manipulate and transfer information throughout the Hypercluster at NASA Lewis Research Center. Each subroutine and its parameters are described in detail. A simple heat flow application using Laplace's equation is included to demonstrate the use of some of the library's subroutines. The manual can be used initially as an introduction to the parallel features provided by the library. Thereafter it can be used as a reference when programming an application.

  1. NSWC Library of Mathematics Subroutines

    DTIC Science & Technology

    1993-01-01

    standards concerning in-line documentation and the style of code cannot be imposed. In generel, all supportive subreutines not intended for direct use are...proprietary or otherwise restricted codes have been permitted ;’ the library. Only general purpose mathematical subroutines for use by the entire NSWCDD...where the source codes are frequently of prime importance), and for general use in applications. Since expertise is so widely scattered, reliable

  2. Space tug automatic docking control study. LOCDOK users manual

    NASA Technical Reports Server (NTRS)

    1974-01-01

    A users's manual for the computer programs involved in a study of the space tug docking simulation is presented. The following subjects are considered: (1) subroutine narratives, (2) program elements, (3) system subroutines, and (4) Univac 1108 cross reference listing. The functional and operational requirements for the computer programming are explained.

  3. Coupled porohyperelastic mass transport (PHEXPT) finite element models for soft tissues using ABAQUS.

    PubMed

    Vande Geest, Jonathan P; Simon, B R; Rigby, Paul H; Newberg, Tyler P

    2011-04-01

    Finite element models (FEMs) including characteristic large deformations in highly nonlinear materials (hyperelasticity and coupled diffusive/convective transport of neutral mobile species) will allow quantitative study of in vivo tissues. Such FEMs will provide basic understanding of normal and pathological tissue responses and lead to optimization of local drug delivery strategies. We present a coupled porohyperelastic mass transport (PHEXPT) finite element approach developed using a commercially available ABAQUS finite element software. The PHEXPT transient simulations are based on sequential solution of the porohyperelastic (PHE) and mass transport (XPT) problems where an Eulerian PHE FEM is coupled to a Lagrangian XPT FEM using a custom-written FORTRAN program. The PHEXPT theoretical background is derived in the context of porous media transport theory and extended to ABAQUS finite element formulations. The essential assumptions needed in order to use ABAQUS are clearly identified in the derivation. Representative benchmark finite element simulations are provided along with analytical solutions (when appropriate). These simulations demonstrate the differences in transient and steady state responses including finite deformations, total stress, fluid pressure, relative fluid, and mobile species flux. A detailed description of important model considerations (e.g., material property functions and jump discontinuities at material interfaces) is also presented in the context of finite deformations. The ABAQUS-based PHEXPT approach enables the use of the available ABAQUS capabilities (interactive FEM mesh generation, finite element libraries, nonlinear material laws, pre- and postprocessing, etc.). PHEXPT FEMs can be used to simulate the transport of a relatively large neutral species (negligible osmotic fluid flux) in highly deformable hydrated soft tissues and tissue-engineered materials.

  4. MEAM interatomic force calculation subroutine for LAMMPS

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Stukowski, A.

    2010-10-25

    Interatomic force and energy calculation subroutine tobe used with the molecular dynamics simulation code LAMMPS (Ref a.). The code evaluates the total energy and atomic forces (energy gradient) according to cubic spine-based variant (Ref b.) of the Modified Embedded Atom Method (MEAM).

  5. Numerical Simulation and Experiments of Fatigue Crack Growth in Multi-Layer Structures of MEMS and Microelectronic Devices

    DTIC Science & Technology

    2006-12-01

    ABAQUS by use of the UEL subroutine feature. The damage variable was defined on averaged variables per element (Roe and Siegmund, 2003). The location of... thermal expansion (CTE) which is similar to silicon. During the anodic bonding process, the stack of silicon and glass wafers is placed on a hot plate and...Brinckmann, T. Siegmund, "Modeling fatigue crack growth with ABAQUS ," 2005 ABAQUS Fracture Review Team Meeting, Providence, RI, (2005). 8. S

  6. Developing an Abaqus *HYPERFOAM Model for M9747 (4003047) Cellular Silicone Foam

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Siranosian, Antranik A.; Stevens, R. Robert

    This report documents work done to develop an Abaqus *HYPERFOAM hyperelastic model for M9747 (4003047) cellular silicone foam for use in quasi-static analyses at ambient temperature. Experimental data, from acceptance tests for 'Pad A' conducted at the Kansas City Plant (KCP), was used to calibrate the model. The data includes gap (relative displacement) and load measurements from three locations on the pad. Thirteen sets of data, from pads with different serial numbers, were provided. The thirty-nine gap-load curves were extracted from the thirteen supplied Excel spreadsheets and analyzed, and from those thirty-nine one set of data, representing a qualitative mean,more » was chosen to calibrate the model. The data was converted from gap and load to nominal (engineering) strain and nominal stress in order to implement it in Abaqus. Strain computations required initial pad thickness estimates. An Abaqus model of a right-circular cylinder was used to evaluate and calibrate the *HYPERFOAM model.« less

  7. The Secondary Development of ABAQUS by using Python and the Application of the Advanced GA

    NASA Astrophysics Data System (ADS)

    Luo, Lilong; Zhao, Meiying

    Realizing the secondary development of the ABAQUS based on the manual of ABAQUS. In order to overcome the prematurity and the worse convergence of the Simple Genetic Algorithm (SGA), a new strategy how to improve the efficiency of the SGA has been put forward. In the new GA, the selection probability and the mutation probability are self-adaptive. Taking the stability of the composite laminates as the target, the optimized laminates sequences and radius of the hatch are analyzed with the help of ABAQUS. Compared with the SGA, the new GA method shows a good consistency, fast convergence and practical feasibility.

  8. Cup-Drawing Behavior of High-Strength Steel Sheets Containing Different Volume Fractions of Martensite

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Choi, Shi-Hoon; Kim, Dae-Wan; Yang, Hoe-Seok

    Planar anisotropy and cup-drawing behavior were investigated for high-strength steel sheets containing different volume fractions of martensite. Macrotexture analysis using XRD was conducted to capture the effect of crystallographic orientation on the planar anisotropy of high-strength steel sheets. A phenomenological yield function, Yld96, which accounts for the anisotropy of yield stress and r-values, was implemented into ABAQUS using the user subroutine UMAT. Cup drawing of high-strength steel sheets was simulated using the FEM code. The profiles of earing and thickness strain were compared with the experimentally measured results.

  9. Numerical analysis of strain localization for transversely isotropic model with non-coaxial flow rule

    NASA Astrophysics Data System (ADS)

    Wei, Ding; Cong-cong, Yu; Chen-hui, Wu; Zheng-yi, Shu

    2018-03-01

    To analyse the strain localization behavior of geomaterials, the forward Euler schemes and the tangent modulus matrix are formulated based on the transversely isotropic yield criterion with non-coaxial flow rule developed by Lade, the program code is implemented based on the user subroutine (UMAT) of ABAQUS. The influence of the material principal direction on the strain localization and the bearing capacity of the structure are investigated and analyzed. Numerical results show the validity and performance of the proposed model in simulating the strain localization behavior of geostructures.

  10. Simulating Initial and Progressive Failure of Open-Hole Composite Laminates under Tension

    NASA Astrophysics Data System (ADS)

    Guo, Zhangxin; Zhu, Hao; Li, Yongcun; Han, Xiaoping; Wang, Zhihua

    2016-12-01

    A finite element (FE) model is developed for the progressive failure analysis of fiber reinforced polymer laminates. The failure criterion for fiber and matrix failure is implemented in the FE code Abaqus using user-defined material subroutine UMAT. The gradual degradation of the material properties is controlled by the individual fracture energies of fiber and matrix. The failure and damage in composite laminates containing a central hole subjected to uniaxial tension are simulated. The numerical results show that the damage model can be used to accurately predicte the progressive failure behaviour both qualitatively and quantitatively.

  11. Airport landside volume V : appendix B ALSIM subroutines.

    DOT National Transportation Integrated Search

    1982-06-01

    This Appendix describes the operation of ten subroutines used to support the AUXILIARY and MAIN programs of ALSIM. Flow charts and listings of all programs are provided. The major portion describes the FORTRAN subprogram FORTM which is used to read i...

  12. Quadratic spline subroutine package

    USGS Publications Warehouse

    Rasmussen, Lowell A.

    1982-01-01

    A continuous piecewise quadratic function with continuous first derivative is devised for approximating a single-valued, but unknown, function represented by a set of discrete points. The quadratic is proposed as a treatment intermediate between using the angular (but reliable, easily constructed and manipulated) piecewise linear function and using the smoother (but occasionally erratic) cubic spline. Neither iteration nor the solution of a system of simultaneous equations is necessary to determining the coefficients. Several properties of the quadratic function are given. A set of five short FORTRAN subroutines is provided for generating the coefficients (QSC), finding function value and derivatives (QSY), integrating (QSI), finding extrema (QSE), and computing arc length and the curvature-squared integral (QSK). (USGS)

  13. A general purpose subroutine for fast fourier transform on a distributed memory parallel machine

    NASA Technical Reports Server (NTRS)

    Dubey, A.; Zubair, M.; Grosch, C. E.

    1992-01-01

    One issue which is central in developing a general purpose Fast Fourier Transform (FFT) subroutine on a distributed memory parallel machine is the data distribution. It is possible that different users would like to use the FFT routine with different data distributions. Thus, there is a need to design FFT schemes on distributed memory parallel machines which can support a variety of data distributions. An FFT implementation on a distributed memory parallel machine which works for a number of data distributions commonly encountered in scientific applications is presented. The problem of rearranging the data after computing the FFT is also addressed. The performance of the implementation on a distributed memory parallel machine Intel iPSC/860 is evaluated.

  14. Expansion and improvement of the FORMA system for response and load analysis. Volume 2C: Listings, finite element FORMA subroutines

    NASA Technical Reports Server (NTRS)

    Wohlen, R. L.

    1976-01-01

    A listing of the source deck of each finite element FORMA subroutine is given to remove the 'black-box' aura of the subroutines so that the analyst may better understand the detailed operations of each subroutine. The FORTRAN 4 programming language is used in all finite element FORMA subroutines.

  15. FORTRAN plotting subroutines for the space plasma laboratory

    NASA Technical Reports Server (NTRS)

    Williams, R.

    1983-01-01

    The computer program known as PLOTRW was custom made to satisfy some of the graphics requirements for the data collected in the Space Plasma Laboratory at the Johnson Space Center (JSC). The general requirements for the program were as follows: (1) all subroutines shall be callable through a FORTRAN source program; (2) all graphs shall fill one page and be properly labeled; (3) there shall be options for linear axes and logarithmic axes; (4) each axis shall have tick marks equally spaced with numeric values printed at the beginning tick mark and at the last tick mark; and (5) there shall be three options for plotting. These are: (1) point plot, (2) line plot and (3) point-line plot. The subroutines were written in FORTRAN IV for the LSI-11 Digital equipment Corporation (DEC) Computer. The program is now operational and can be run on any TEKTRONICX graphics terminal that uses a DEC Real-Time-11 (RT-11) operating system.

  16. GERTS GQ User's Manual.

    ERIC Educational Resources Information Center

    Akiba, Y.; And Others

    This user's manual for the simulation program Graphical Evaluation and Review Technique (GERT) GQ contains sections on nodes, branches, program input description and format, and program output, as well as examples. Also included is a programmer's manual which contains information on scheduling, subroutine descriptions, COMMON Variables, and…

  17. Evaluation of the finite element software ABAQUS for biomechanical modelling of biphasic tissues.

    PubMed

    Wu, J Z; Herzog, W; Epstein, M

    1998-02-01

    The biphasic cartilage model proposed by Mow et al. (1980) has proven successful to capture the essential mechanical features of articular cartilage. In order to analyse the joint contact mechanics in real, anatomical joints, the cartilage model needs to be implemented into a suitable finite element code to approximate the irregular surface geometries of such joints. However, systematic and extensive evaluation of the capacity of commercial software for modelling the contact mechanics with biphasic cartilage layers has not been made. This research was aimed at evaluating the commercial finite element software ABAQUS for analysing biphasic soft tissues. The solutions obtained using ABAQUS were compared with those obtained using other finite element models and analytical solutions for three numerical tests: an unconfined indentation test, a test with the contact of a spherical cartilage surface with a rigid plate, and an axi-symmetric joint contact test. It was concluded that the biphasic cartilage model can be implemented into the commercial finite element software ABAQUS to analyse practical joint contact problems with biphasic articular cartilage layers.

  18. Simulation of a Canard in Fluid Flow Driven by a Piezoelectric Beam with a Software Control Loop

    DTIC Science & Technology

    2014-04-01

    The canard is actuated by a piezoelectric beam that bends as voltage is applied. The voltage is controlled by a software subroutine that measures...Dynamic system Modeling Co-simulation Simulation Abaqus Finite element analysis (FEA) Finite element method (FEM) Computational...is unlimited. i CONTENTS Page Introduction 1 Model Description 1 Fluid Model 2 Structural Model 3 Control Subroutine 4 Results 4

  19. C-statistic fitting routines: User's manual and reference guide

    NASA Technical Reports Server (NTRS)

    Nousek, John A.; Farwana, Vida

    1991-01-01

    The computer program is discussed which can read several input files and provide a best set of values for the functions provided by the user, using either C-statistic or the chi(exp 2) statistic method. The program consists of one main routine and several functions and subroutines. Detail descriptions of each function and subroutine is presented. A brief description of the C-statistic and the reason for its application is also presented.

  20. Numerical Simulation of Roller Levelling using SIMULIA Abaqus

    NASA Astrophysics Data System (ADS)

    Trusov, K. A.; Mishnev, P. A.; Kopaev, O. V.; Nushtaev, D. V.

    2017-12-01

    The finite element (FE) 2D-model of roller levelling process is developed in the SIMILIA Abaqus. The objective of this paper is development FE-model and investigation of adjustable parameters of roller leveller together with elastic-plastic material behaviour. Properties of the material were determined experimentally. After levelling, the strip had a residual stress distribution. The longbow after cutting is predicted too. Recommendation for practical use were proposed.

  1. A 3D moisture-stress FEM analysis for time dependent problems in timber structures

    NASA Astrophysics Data System (ADS)

    Fortino, Stefania; Mirianon, Florian; Toratti, Tomi

    2009-11-01

    This paper presents a 3D moisture-stress numerical analysis for timber structures under variable humidity and load conditions. An orthotropic viscoelastic-mechanosorptive material model is specialized on the basis of previous models. Both the constitutive model and the equations needed to describe the moisture flow across the structure are implemented into user subroutines of the Abaqus finite element code and a coupled moisture-stress analysis is performed for several types of mechanical loads and moisture changes. The presented computational approach is validated by analyzing some wood tests described in the literature and comparing the computational results with the reported experimental data.

  2. Determination of Fracture Parameters for Multiple Cracks of Laminated Composite Finite Plate

    NASA Astrophysics Data System (ADS)

    Srivastava, Amit Kumar; Arora, P. K.; Srivastava, Sharad Chandra; Kumar, Harish; Lohumi, M. K.

    2018-04-01

    A predictive method for estimation of stress state at zone of crack tip and assessment of remaining component lifetime depend on the stress intensity factor (SIF). This paper discusses the numerical approach for prediction of first ply failure load (FL), progressive failure load, SIF and critical SIF for multiple cracks configurations of laminated composite finite plate using finite element method (FEM). The Hashin and Chang failure criterion are incorporated in ABAQUS using subroutine approach user defined field variables (USDFLD) for prediction of progressive fracture response of laminated composite finite plate, which is not directly available in the software. A tensile experiment on laminated composite finite plate with stress concentration is performed to validate the numerically predicted subroutine results, shows excellent agreement. The typical results are presented to examine effect of changing the crack tip distance (S), crack offset distance (H), and stacking fiber angle (θ) on FL, and SIF .

  3. Expansion and improvement of the FORMA system for response and load analysis. Volume 2A: Listings, dense FORMA subroutines

    NASA Technical Reports Server (NTRS)

    Wohlen, R. L.

    1976-01-01

    A listing of the source deck of each dense FORMA subroutine is given to remove the 'black-box' aura of the subroutines so that the analyst may better understand the detail operations of each subroutine. The FORTRAN 4 programming language is used throughout.

  4. Goodman and Kruskal's TAU-B Statistics: A Fortran-77 Subroutine.

    ERIC Educational Resources Information Center

    Berry, Kenneth J.; Mielke, Paul W., Jr.

    1986-01-01

    An algorithm and associated FORTRAN-77 computer subroutine are described for computing Goodman and Kruskal's tau-b statistic along with the associated nonasymptotic probability value under the null hypothesis tau=O. (Author)

  5. Modeling and simulation of Charpy impact test of maraging steel 300 using Abaqus

    NASA Astrophysics Data System (ADS)

    Madhusudhan, D.; Chand, Suresh; Ganesh, S.; Saibhargavi, U.

    2018-03-01

    This work emphasizes the modeling and simulation of Charpy impact test to evaluate fracture energy at different pendulum velocities of armor maraging steel 300 using ABAQUS. To evaluate the fracture energy, V-notch specimen is fractured using the Johnson and Cook Damage model. The Charpy impact tests are of great importance related to fracture properties of steels. The objective of this work is to present absorbed energy variation at pendulum velocities of 5 m/sec, 6 m/sec, 7 m/sec and 9 m/sec in addition to stress distribution at v-notch. Finite Element Method of modeling for three dimensional specimens is used for simulation in commercial software of ABAQUS.

  6. Advancement and Implementation of Integrated Computational Materials Engineering (ICME) for Aerospace Applications

    DTIC Science & Technology

    2010-03-01

    of sub-routines Thermal history • Abaqus FEM engine mature applied within ABAQUS Residual stress & Distortion • Unknown maturity for HTC • Focused...investment. The committee’s ICME vision is comprehensive, expansive , and involves the entire materials community. The scope of this white paper is...Software • Continuum FEM for fluid flow, heat Mold Fill • FEM implementation mature flow and stress analysis Thermal & mushy zone history • Needs

  7. Parametric analysis and temperature effect of deployable hinged shells using shape memory polymers

    NASA Astrophysics Data System (ADS)

    Tao, Ran; Yang, Qing-Sheng; He, Xiao-Qiao; Liew, Kim-Meow

    2016-11-01

    Shape memory polymers (SMPs) are a class of intelligent materials, which are defined by their capacity to store a temporary shape and recover an original shape. In this work, the shape memory effect of SMP deployable hinged shell is simulated by using compiled user defined material subroutine (UMAT) subroutine of ABAQUS. Variations of bending moment and strain energy of the hinged shells with different temperatures and structural parameters in the loading process are given. The effects of the parameters and temperature on the nonlinear deformation process are emphasized. The entire thermodynamic cycle of SMP deployable hinged shell includes loading at high temperature, load carrying with cooling, unloading at low temperature and recovering the original shape with heating. The results show that the complicated thermo-mechanical deformation and shape memory effect of SMP deployable hinge are influenced by the structural parameters and temperature. The design ability of SMP smart hinged structures in practical application is prospected.

  8. Modeling delamination of FRP laminates under low velocity impact

    NASA Astrophysics Data System (ADS)

    Jiang, Z.; Wen, H. M.; Ren, S. L.

    2017-09-01

    Fiber reinforced plastic laminates (FRP) have been increasingly used in various engineering such as aeronautics, astronautics, transportation, naval architecture and their impact response and failure are a major concern in academic community. A new numerical model is suggested for fiber reinforced plastic composites. The model considers that FRP laminates has been constituted by unidirectional laminated plates with adhesive layers. A modified adhesive layer damage model that considering strain rate effects is incorporated into the ABAQUS / EXPLICIT finite element program by the user-defined material subroutine VUMAT. It transpires that the present model predicted delamination is in good agreement with the experimental results for low velocity impact.

  9. Subroutines GEORGE and DRASTC simplify operation of automatic digital plotter

    NASA Technical Reports Server (NTRS)

    Englel, F., III; Gray, W. H.; Richard, P. J.

    1967-01-01

    FORTRAN language subroutines enable the production of a tape for a 360-30 tape unit that controls the CALCOMP 566 Digital Incremental Plotter. This provides the plotter with instructions for graphically displaying data points with the proper scaling of axes, numbering, lettering, and tic marking.

  10. Thermal APU/hydraulics analysis program. User's guide and programmer's manual

    NASA Technical Reports Server (NTRS)

    Deluna, T. A.

    1976-01-01

    The User's Guide information plus program description necessary to run and have a general understanding of the Thermal APU/Hydraulics Analysis Program (TAHAP) is described. This information consists of general descriptions of the APU/hydraulic system and the TAHAP model, input and output data descriptions, and specific subroutine requirements. Deck setups and input data formats are included and other necessary and/or helpful information for using TAHAP is given. The math model descriptions for the driver program and each of its supporting subroutines are outlined.

  11. Tip vortex computer code SRATIP. User's guide

    NASA Technical Reports Server (NTRS)

    Levy, R.; Lin, S. J.

    1985-01-01

    This User's Guide applies to the three dimensional viscous flow forward marching analysis, PEPSIG, as used for the calculation of the helicopter tip vortex flow field. The guide presents a discussion of the program flow and subroutines, as well as a list of sample input and output.

  12. Toward high-speed 3D nonlinear soft tissue deformation simulations using Abaqus software.

    PubMed

    Idkaidek, Ashraf; Jasiuk, Iwona

    2015-12-01

    We aim to achieve a fast and accurate three-dimensional (3D) simulation of a porcine liver deformation under a surgical tool pressure using the commercial finite element software Abaqus. The liver geometry is obtained using magnetic resonance imaging, and a nonlinear constitutive law is employed to capture large deformations of the tissue. Effects of implicit versus explicit analysis schemes, element type, and mesh density on computation time are studied. We find that Abaqus explicit and implicit solvers are capable of simulating nonlinear soft tissue deformations accurately using first-order tetrahedral elements in a relatively short time by optimizing the element size. This study provides new insights and guidance on accurate and relatively fast nonlinear soft tissue simulations. Such simulations can provide force feedback during robotic surgery and allow visualization of tissue deformations for surgery planning and training of surgical residents.

  13. Progressive Failure And Life Prediction of Ceramic and Textile Composites

    NASA Technical Reports Server (NTRS)

    Xue, David Y.; Shi, Yucheng; Katikala, Madhu; Johnston, William M., Jr.; Card, Michael F.

    1998-01-01

    An engineering approach to predict the fatigue life and progressive failure of multilayered composite and textile laminates is presented. Analytical models which account for matrix cracking, statistical fiber failures and nonlinear stress-strain behavior have been developed for both composites and textiles. The analysis method is based on a combined micromechanics, fracture mechanics and failure statistics analysis. Experimentally derived empirical coefficients are used to account for the interface of fiber and matrix, fiber strength, and fiber-matrix stiffness reductions. Similar approaches were applied to textiles using Repeating Unit Cells. In composite fatigue analysis, Walker's equation is applied for matrix fatigue cracking and Heywood's formulation is used for fiber strength fatigue degradation. The analysis has been compared with experiment with good agreement. Comparisons were made with Graphite-Epoxy, C/SiC and Nicalon/CAS composite materials. For textile materials, comparisons were made with triaxial braided and plain weave materials under biaxial or uniaxial tension. Fatigue predictions were compared with test data obtained from plain weave C/SiC materials tested at AS&M. Computer codes were developed to perform the analysis. Composite Progressive Failure Analysis for Laminates is contained in the code CPFail. Micromechanics Analysis for Textile Composites is contained in the code MicroTex. Both codes were adapted to run as subroutines for the finite element code ABAQUS and CPFail-ABAQUS and MicroTex-ABAQUS. Graphic user interface (GUI) was developed to connect CPFail and MicroTex with ABAQUS.

  14. Simulation of Weld Mechanical Behavior to Include Welding-Induced Residual Stress and Distortion: Coupling of SYSWELD and Abaqus Codes

    DTIC Science & Technology

    2015-11-01

    Memorandum Simulation of Weld Mechanical Behavior to Include Welding -Induced Residual Stress and Distortion: Coupling of SYSWELD and Abaqus Codes... Weld Mechanical Behavior to Include Welding -Induced Residual Stress and Distortion: Coupling of SYSWELD and Abaqus Codes by Charles R. Fisher...TYPE Technical Report 3. DATES COVERED (From - To) Dec 2013 – July 2015 4. TITLE AND SUBTITLE Simulation of Weld Mechanical Behavior to Include

  15. Simulation of Weld Mechanical Behavior to Include Welding Induced Residual Stress and Distortion: Coupling of SYSWELD and Abaqus Codes

    DTIC Science & Technology

    2015-11-01

    Memorandum Simulation of Weld Mechanical Behavior to Include Welding -Induced Residual Stress and Distortion: Coupling of SYSWELD and Abaqus Codes... Weld Mechanical Behavior to Include Welding -Induced Residual Stress and Distortion: Coupling of SYSWELD and Abaqus Codes by Charles R. Fisher...TYPE Technical Report 3. DATES COVERED (From - To) Dec 2013 – July 2015 4. TITLE AND SUBTITLE Simulation of Weld Mechanical Behavior to Include

  16. Coupling of a structural analysis and flow simulation for short-fiber-reinforced polymers: property prediction and transfer of results

    NASA Astrophysics Data System (ADS)

    Kröner, C.; Altenbach, H.; Naumenko, K.

    2009-05-01

    The aim of this paper is to discuss the basic theories of interfaces able to transfer the results of an injection molding analyis of fiber-reinforced polymers, performed by using the commercial computer code Moldflow, to the structural analysis program ABAQUS. The elastic constants of the materials, such as Young's modulus, shear modulus, and Poisson's ratio, which depend on both the fiber content and the degree of fiber orientation, were calculated not by the usual method of "orientation averaging," but with the help of linear functions fitted to experimental data. The calculation and transfer of all needed data, such as material properties, geometry, directions of anisotropy, and so on, is performed by an interface developed. The interface is suit able for midplane elements in Moldflow. It calculates and transfers to ABAQUS all data necessary for the use of shell elements. In addition, a method is described how a nonlinear orthotropic behavior can be modeled starting from the generalized Hooke's law. It is also shown how such a model can be implemented in ABAQUS by means of a material subroutine. The results obtained according to this subroutine are compared with those based on an orthotropic, linear, elastic simulation.

  17. NASA Lewis steady-state heat pipe code users manual

    NASA Technical Reports Server (NTRS)

    Tower, Leonard K.; Baker, Karl W.; Marks, Timothy S.

    1992-01-01

    The NASA Lewis heat pipe code was developed to predict the performance of heat pipes in the steady state. The code can be used as a design tool on a personal computer or with a suitable calling routine, as a subroutine for a mainframe radiator code. A variety of wick structures, including a user input option, can be used. Heat pipes with multiple evaporators, condensers, and adiabatic sections in series and with wick structures that differ among sections can be modeled. Several working fluids can be chosen, including potassium, sodium, and lithium, for which monomer-dimer equilibrium is considered. The code incorporates a vapor flow algorithm that treats compressibility and axially varying heat input. This code facilitates the determination of heat pipe operating temperatures and heat pipe limits that may be encountered at the specified heat input and environment temperature. Data are input to the computer through a user-interactive input subroutine. Output, such as liquid and vapor pressures and temperatures, is printed at equally spaced axial positions along the pipe as determined by the user.

  18. NASA Lewis steady-state heat pipe code users manual

    NASA Astrophysics Data System (ADS)

    Tower, Leonard K.; Baker, Karl W.; Marks, Timothy S.

    1992-06-01

    The NASA Lewis heat pipe code was developed to predict the performance of heat pipes in the steady state. The code can be used as a design tool on a personal computer or with a suitable calling routine, as a subroutine for a mainframe radiator code. A variety of wick structures, including a user input option, can be used. Heat pipes with multiple evaporators, condensers, and adiabatic sections in series and with wick structures that differ among sections can be modeled. Several working fluids can be chosen, including potassium, sodium, and lithium, for which monomer-dimer equilibrium is considered. The code incorporates a vapor flow algorithm that treats compressibility and axially varying heat input. This code facilitates the determination of heat pipe operating temperatures and heat pipe limits that may be encountered at the specified heat input and environment temperature. Data are input to the computer through a user-interactive input subroutine. Output, such as liquid and vapor pressures and temperatures, is printed at equally spaced axial positions along the pipe as determined by the user.

  19. Enhancing the ABAQUS Thermomechanics Code to Simulate Steady and Transient Fuel Rod Behavior

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    R. L. Williamson; D. A. Knoll

    2009-09-01

    A powerful multidimensional fuels performance capability, applicable to both steady and transient fuel behavior, is developed based on enhancements to the commercially available ABAQUS general-purpose thermomechanics code. Enhanced capabilities are described, including: UO2 temperature and burnup dependent thermal properties, solid and gaseous fission product swelling, fuel densification, fission gas release, cladding thermal and irradiation creep, cladding irradiation growth , gap heat transfer, and gap/plenum gas behavior during irradiation. The various modeling capabilities are demonstrated using a 2D axisymmetric analysis of the upper section of a simplified multi-pellet fuel rod, during both steady and transient operation. Computational results demonstrate the importancemore » of a multidimensional fully-coupled thermomechanics treatment. Interestingly, many of the inherent deficiencies in existing fuel performance codes (e.g., 1D thermomechanics, loose thermo-mechanical coupling, separate steady and transient analysis, cumbersome pre- and post-processing) are, in fact, ABAQUS strengths.« less

  20. Numerical Analysis of Deflections of Multi-Layered Beams

    NASA Astrophysics Data System (ADS)

    Biliński, Tadeusz; Socha, Tomasz

    2015-03-01

    The paper concerns the rheological bending problem of wooden beams reinforced with embedded composite bars. A theoretical model of the behaviour of a multi-layered beam is presented. The component materials of this beam are described with equations for the linear viscoelastic five-parameter rheological model. Two numerical analysis methods for the long-term response of wood structures are presented. The first method has been developed with SCILAB software. The second one has been developed with the finite element calculation software ABAQUS and user subroutine UMAT. Laboratory investigations were conducted on sample beams of natural dimensions in order to validate the proposed theoretical model and verify numerical simulations. Good agreement between experimental measurements and numerical results is observed.

  1. Prediction of the effect of temperature on impact damage in carbon/epoxy laminates

    NASA Astrophysics Data System (ADS)

    Gómez del Río, T.; Zaera, R.; Navarro, C.

    2003-09-01

    The effect of temperature on impact damage in Carbon Fiber Reinforced Plastic (CFRP) tape laminates produced by low velocity impact was studied by numerical simulations made to model drop weight tower impact tests on carbon/epoxy laminate composites. The damage model was implemented into a user subroutine of the finite element code ABAQUS. The model takes into account the thermal stresses resulting form the different thermal expansion coefficients in each ply of the laminate. The tests and simulations show how temperature affects the propagation of each damage mode. Matrix cracking and delamination are greatly affected by low temperature, white matrix crushing and fibre failure appear only in a small region at all the impact energies and test temperatures.

  2. Users manual for the Variable dimension Automatic Synthesis Program (VASP)

    NASA Technical Reports Server (NTRS)

    White, J. S.; Lee, H. Q.

    1971-01-01

    A dictionary and some problems for the Variable Automatic Synthesis Program VASP are submitted. The dictionary contains a description of each subroutine and instructions on its use. The example problems give the user a better perspective on the use of VASP for solving problems in modern control theory. These example problems include dynamic response, optimal control gain, solution of the sampled data matrix Ricatti equation, matrix decomposition, and pseudo inverse of a matrix. Listings of all subroutines are also included. The VASP program has been adapted to run in the conversational mode on the Ames 360/67 computer.

  3. Mathematical modeling of microstructural development in hypoeutectic cast iron

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Maijer, D.; Cockcroft, S.L.; Patt, W.

    A mathematical heat-transfer/microstructural model has been developed to predict the evolution of proeutectic austenite, white iron eutectic, and gray iron eutectic during solidification of hypoeutectic cast iron, based on the commercial finite-element code ABAQUS. Specialized routines which employ relationships describing nucleation and growth of equiaxed primary austenite, gray iron eutectic, and white iron eutectic have been formulated and incorporated into ABAQUS through user-specified subroutines. The relationships used in the model to describe microstructural evolution have been adapted from relationships describing equiaxed growth in the literature. The model has been validated/fine tuned against temperature data collected from a QuiK-Cup sample, whichmore » contained a thermocouple embedded approximately in the center of the casting. The phase distribution predicted with the model has been compared to the measured phase distribution inferred from the variation in hardness within the QuiK-Cup sample and from image analysis of photomicrographs of the polished and etched microstructure. Overall, the model results were found to agree well with the measured distribution of the microstructure.« less

  4. Structural dynamics payload loads estimates: User guide

    NASA Technical Reports Server (NTRS)

    Shanahan, T. G.; Engels, R. C.

    1982-01-01

    This User Guide with an overview of an integration scheme to determine the response of a launch vehicle with multiple payloads. Chapter II discusses the software package associated with the integration scheme together with several sample problems. A short cut version of the integration technique is also discussed. The Guide concludes with a list of references and the listings of the subroutines.

  5. A Model for Simulating the Response of Aluminum Honeycomb Structure to Transverse Loading

    NASA Technical Reports Server (NTRS)

    Ratcliffe, James G.; Czabaj, Michael W.; Jackson, Wade C.

    2012-01-01

    A 1-dimensional material model was developed for simulating the transverse (thickness-direction) loading and unloading response of aluminum honeycomb structure. The model was implemented as a user-defined material subroutine (UMAT) in the commercial finite element analysis code, ABAQUS(Registered TradeMark)/Standard. The UMAT has been applied to analyses for simulating quasi-static indentation tests on aluminum honeycomb-based sandwich plates. Comparison of analysis results with data from these experiments shows overall good agreement. Specifically, analyses of quasi-static indentation tests yielded accurate global specimen responses. Predicted residual indentation was also in reasonable agreement with measured values. Overall, this simple model does not involve a significant computational burden, which makes it more tractable to simulate other damage mechanisms in the same analysis.

  6. Attitude dynamics simulation subroutines for systems of hinge-connected rigid bodies with nonrigid appendages

    NASA Technical Reports Server (NTRS)

    Fleischer, G. E.; Likins, P. W.

    1975-01-01

    Three computer subroutines designed to solve the vector-dyadic differential equations of rotational motion for systems that may be idealized as a collection of hinge-connected rigid bodies assembled in a tree topology, with an optional flexible appendage attached to each body are reported. Deformations of the appendages are mathematically represented by modal coordinates and are assumed small. Within these constraints, the subroutines provide equation solutions for (1) the most general case of unrestricted hinge rotations, with appendage base bodies nominally rotating at a constant speed, (2) the case of unrestricted hinge rotations between rigid bodies, with the restriction that those rigid bodies carrying appendages are nominally nonspinning, and (3) the case of small hinge rotations and nominally nonrotating appendages. Sample problems and their solutions are presented to illustrate the utility of the computer programs.

  7. User's manual for the coupled rotor/airframe vibration analysis graphic package

    NASA Technical Reports Server (NTRS)

    Studwell, R. E.

    1982-01-01

    User instructions for a graphics package for coupled rotor/airframe vibration analysis are presented. Responses to plot package messages which the user must make to activate plot package operations and options are described. Installation instructions required to set up the program on the CDC system are included. The plot package overlay structure and subroutines which have to be modified for the CDC system are also described. Operating instructions for CDC applications are included.

  8. A User’s Manual for Electromagnetic Surface Patch (ESP) Code. Version II. Polygonal Plates and Wires.

    DTIC Science & Technology

    1983-09-01

    to geometries not large in terms of wavelength and the lack of analytical results which can provide physical insight into the problem. The first...EPTS)*Ŗ) STPM *2. ’TP’ (CABS (ETPS)*Ŗ) STTHi2.*TP*(CARS(ETTS)*Ŗ) RETURN - 1 END 296 do APPENDIX 37 * SUBROUTINE SURFFY SUBROUTINE.SURF!? (KXl,YN1...D-Ai135 837 A USER’S MAiNUAfL FOR ELECTROMAGNETIC SURFACE PATCH (ESP) 1 /4 CODE VERSION 11 P.-(U) OHIO STATE UNIV COLUMBUS U CLAS ELECTROSCIENCE LAB E

  9. Enhancing the ABAQUS thermomechanics code to simulate multipellet steady and transient LWR fuel rod behavior

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    R. L. Williamson

    A powerful multidimensional fuels performance analysis capability, applicable to both steady and transient fuel behavior, is developed based on enhancements to the commercially available ABAQUS general-purpose thermomechanics code. Enhanced capabilities are described, including: UO2 temperature and burnup dependent thermal properties, solid and gaseous fission product swelling, fuel densification, fission gas release, cladding thermal and irradiation creep, cladding irradiation growth, gap heat transfer, and gap/plenum gas behavior during irradiation. This new capability is demonstrated using a 2D axisymmetric analysis of the upper section of a simplified multipellet fuel rod, during both steady and transient operation. Comparisons are made between discrete andmore » smeared-pellet simulations. Computational results demonstrate the importance of a multidimensional, multipellet, fully-coupled thermomechanical approach. Interestingly, many of the inherent deficiencies in existing fuel performance codes (e.g., 1D thermomechanics, loose thermomechanical coupling, separate steady and transient analysis, cumbersome pre- and post-processing) are, in fact, ABAQUS strengths.« less

  10. Hygrothermal Simulation of Wood Exposed To the Effect of External Climate

    NASA Astrophysics Data System (ADS)

    Dohnal, Jakub; Hradil, Petr; Pencik, Jan

    2017-10-01

    The article is focused on simulation of moisture transfer in wood of norway spruce (Picea abies L.). Experimental specimen was exposed to the northern climatic conditions in Lund University, Sweden. The moisture content of wood was measured 10 mm from the surface for nearly three years. The ABAQUS program was used for numerical modelling of moisture transfer simulation in 3D. The surface sorption of wood was simulated using user defined subroutine DFLUX developed by VTT Research Centre of Finland Ltd. for the needs of European Project Durable Timber Bridges. Climate data for the analysis was used from insitu measurement nearby realized by weather station. The temperature, relative humidity of the air and precipitation data was record each hour. Numerical analysis took into account influence of rain effect on different parts of specimen surface.

  11. Damage Simulation in Non-Crimp Fabric Composite Plates Subjected to Impact Loads

    NASA Technical Reports Server (NTRS)

    Satyanarayana, Arunkumar; Bogert, Philip B.; Aitharaju, Venkat; Aashat, Satvir; Kia, Hamid

    2014-01-01

    Progressive failure analysis (PFA) of non-crimp fabric (NCF) composite laminates subjected to low velocity impact loads was performed using the COmplete STress Reduction (COSTR) damage model implemented through VUMAT and UMAT41 user subroutines in the frame works of the commercial finite element programs ABAQUS/Explicit and LS-DYNA, respectively. To validate the model, low velocity experiments were conducted and detailed correlations between the predictions and measurements for both intra-laminar and inter-laminar failures were made. The developed material and damage model predicts the peak impact load and duration very close with the experimental results. Also, the simulation results of delamination damage between the ply interfaces, in-plane matrix damages and fiber damages were all in good agreement with the measurements from the non-destructive evaluation data.

  12. Simulating Progressive Damage of Notched Composite Laminates with Various Lamination Schemes

    NASA Astrophysics Data System (ADS)

    Mandal, B.; Chakrabarti, A.

    2017-05-01

    A three dimensional finite element based progressive damage model has been developed for the failure analysis of notched composite laminates. The material constitutive relations and the progressive damage algorithms are implemented into finite element code ABAQUS using user-defined subroutine UMAT. The existing failure criteria for the composite laminates are modified by including the failure criteria for fiber/matrix shear damage and delamination effects. The proposed numerical model is quite efficient and simple compared to other progressive damage models available in the literature. The efficiency of the present constitutive model and the computational scheme is verified by comparing the simulated results with the results available in the literature. A parametric study has been carried out to investigate the effect of change in lamination scheme on the failure behaviour of notched composite laminates.

  13. Digital Avionics Information System (DAIS): Training Requirements Analysis Model Users Guide. Final Report.

    ERIC Educational Resources Information Center

    Czuchry, Andrew J.; And Others

    This user's guide describes the functions, logical operations and subroutines, input data requirements, and available outputs of the Training Requirements Analysis Model (TRAMOD), a computerized analytical life cycle cost modeling system for use in the early stages of system design. Operable in a stand-alone mode, TRAMOD can be used for the…

  14. Finite element method for viscoelastic medium with damage and the application to structural analysis of solid rocket motor grain

    NASA Astrophysics Data System (ADS)

    Deng, Bin; Shen, ZhiBin; Duan, JingBo; Tang, GuoJin

    2014-05-01

    This paper studies the damage-viscoelastic behavior of composite solid propellants of solid rocket motors (SRM). Based on viscoelastic theories and strain equivalent hypothesis in damage mechanics, a three-dimensional (3-D) nonlinear viscoelastic constitutive model incorporating with damage is developed. The resulting viscoelastic constitutive equations are numerically discretized by integration algorithm, and a stress-updating method is presented by solving nonlinear equations according to the Newton-Raphson method. A material subroutine of stress-updating is made up and embedded into commercial code of Abaqus. The material subroutine is validated through typical examples. Our results indicate that the finite element results are in good agreement with the analytical ones and have high accuracy, and the suggested method and designed subroutine are efficient and can be further applied to damage-coupling structural analysis of practical SRM grain.

  15. Spectrally formulated user-defined element in conventional finite element environment for wave motion analysis in 2-D composite structures

    NASA Astrophysics Data System (ADS)

    Khalili, Ashkan; Jha, Ratneshwar; Samaratunga, Dulip

    2016-11-01

    Wave propagation analysis in 2-D composite structures is performed efficiently and accurately through the formulation of a User-Defined Element (UEL) based on the wavelet spectral finite element (WSFE) method. The WSFE method is based on the first-order shear deformation theory which yields accurate results for wave motion at high frequencies. The 2-D WSFE model is highly efficient computationally and provides a direct relationship between system input and output in the frequency domain. The UEL is formulated and implemented in Abaqus (commercial finite element software) for wave propagation analysis in 2-D composite structures with complexities. Frequency domain formulation of WSFE leads to complex valued parameters, which are decoupled into real and imaginary parts and presented to Abaqus as real values. The final solution is obtained by forming a complex value using the real number solutions given by Abaqus. Five numerical examples are presented in this article, namely undamaged plate, impacted plate, plate with ply drop, folded plate and plate with stiffener. Wave motions predicted by the developed UEL correlate very well with Abaqus simulations. The results also show that the UEL largely retains computational efficiency of the WSFE method and extends its ability to model complex features.

  16. Fracture simulation of restored teeth using a continuum damage mechanics failure model.

    PubMed

    Li, Haiyan; Li, Jianying; Zou, Zhenmin; Fok, Alex Siu-Lun

    2011-07-01

    The aim of this paper is to validate the use of a finite-element (FE) based continuum damage mechanics (CDM) failure model to simulate the debonding and fracture of restored teeth. Fracture testing of plastic model teeth, with or without a standard Class-II MOD (mesial-occusal-distal) restoration, was carried out to investigate their fracture behavior. In parallel, 2D FE models of the teeth are constructed and analyzed using the commercial FE software ABAQUS. A CDM failure model, implemented into ABAQUS via the user element subroutine (UEL), is used to simulate the debonding and/or final fracture of the model teeth under a compressive load. The material parameters needed for the CDM model to simulate fracture are obtained through separate mechanical tests. The predicted results are then compared with the experimental data of the fracture tests to validate the failure model. The failure processes of the intact and restored model teeth are successfully reproduced by the simulation. However, the fracture parameters obtained from testing small specimens need to be adjusted to account for the size effect. The results indicate that the CDM model is a viable model for the prediction of debonding and fracture in dental restorations. Copyright © 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  17. Multiple-taper spectral analysis: A stand-alone C-subroutine

    NASA Astrophysics Data System (ADS)

    Lees, Jonathan M.; Park, Jeffrey

    1995-03-01

    A simple set of subroutines in ANSI-C are presented for multiple taper spectrum estimation. The multitaper approach provides an optimal spectrum estimate by minimizing spectral leakage while reducing the variance of the estimate by averaging orthogonal eigenspectrum estimates. The orthogonal tapers are Slepian nπ prolate functions used as tapers on the windowed time series. Because the taper functions are orthogonal, combining them to achieve an average spectrum does not introduce spurious correlations as standard smoothed single-taper estimates do. Furthermore, estimates of the degrees of freedom and F-test values at each frequency provide diagnostics for determining levels of confidence in narrow band (single frequency) periodicities. The program provided is portable and has been tested on both Unix and Macintosh systems.

  18. Damage evaluation of reinforced concrete frame based on a combined fiber beam model

    NASA Astrophysics Data System (ADS)

    Shang, Bing; Liu, ZhanLi; Zhuang, Zhuo

    2014-04-01

    In order to analyze and simulate the impact collapse or seismic response of the reinforced concrete (RC) structures, a combined fiber beam model is proposed by dividing the cross section of RC beam into concrete fiber and steel fiber. The stress-strain relationship of concrete fiber is based on a model proposed by concrete codes for concrete structures. The stress-strain behavior of steel fiber is based on a model suggested by others. These constitutive models are implemented into a general finite element program ABAQUS through the user defined subroutines to provide effective computational tools for the inelastic analysis of RC frame structures. The fiber model proposed in this paper is validated by comparing with experiment data of the RC column under cyclical lateral loading. The damage evolution of a three-dimension frame subjected to impact loading is also investigated.

  19. Failure Analysis of a Sheet Metal Blanking Process Based on Damage Coupling Model

    NASA Astrophysics Data System (ADS)

    Wen, Y.; Chen, Z. H.; Zang, Y.

    2013-11-01

    In this paper, a blanking process of sheet metal is studied by the methods of numerical simulation and experimental observation. The effects of varying technological parameters related to the quality of products are investigated. An elastoplastic constitutive equation accounting for isotropic ductile damage is implemented into the finite element code ABAQUS with a user-defined material subroutine UMAT. The simulations of the damage evolution and ductile fracture in a sheet metal blanking process have been carried out by the FEM. In order to guarantee computation accuracy and avoid numerical divergence during large plastic deformation, a specified remeshing technique is successively applied when severe element distortion occurs. In the simulation, the evolutions of damage at different stage of the blanking process have been evaluated and the distributions of damage obtained from simulation are in proper agreement with the experimental results.

  20. Experiment Analysis and Modelling of Compaction Behaviour of Ag60Cu30Sn10 Mixed Metal Powders

    NASA Astrophysics Data System (ADS)

    Zhou, Mengcheng; Huang, Shangyu; Liu, Wei; Lei, Yu; Yan, Shiwei

    2018-03-01

    A novel process method combines powder compaction and sintering was employed to fabricate thin sheets of cadmium-free silver based filler metals, the compaction densification behaviour of Ag60Cu30Sn10 mixed metal powders was investigated experimentally. Based on the equivalent density method, the density-dependent Drucker-Prager Cap (DPC) model was introduced to model the powder compaction behaviour. Various experiment procedures were completed to determine the model parameters. The friction coefficients in lubricated and unlubricated die were experimentally determined. The determined material parameters were validated by experiments and numerical simulation of powder compaction process using a user subroutine (USDFLD) in ABAQUS/Standard. The good agreement between the simulated and experimental results indicates that the determined model parameters are able to describe the compaction behaviour of the multicomponent mixed metal powders, which can be further used for process optimization simulations.

  1. Cyclic softening based on dislocation annihilation at sub-cell boundary for SA333 Grade-6 C-Mn steel

    NASA Astrophysics Data System (ADS)

    Bhattacharjee, S.; Dhar, S.; Acharyya, S. K.; Gupta, S. K.

    2018-01-01

    In this work, the response of SA333 Grade-6 C-Mn steel subjected to uniaxial and in-phase biaxial tension-torsion cyclic loading is experimented and an attempt is made to model the material behaviour. Experimentally observed cyclic softening is modelled based on ‘dislocation annihilation at low angle grain boundary’, while Ohno-Wang kinematic hardening rule is used to simulate the stress-strain hysteresis loops. The relevant material parameters are extracted from the appropriate experimental results and metallurgical investigations. The material model is plugged as user material subroutine into ABAQUS FE platform to simulate pre-saturation low cycle fatigue loops with cyclic softening and other cyclic plastic behaviour under prescribed loading. The stress-strain hysteresis loops and peak stress with cycles were compared with the experimental results and good agreements between experimental and simulated results validated the material model.

  2. T-H-A-T-S: timber-harvesting-and-transport-simulator: with subroutines for Appalachian logging

    Treesearch

    A. Jeff Martin

    1975-01-01

    A computer program for simulating harvesting operations is presented. Written in FORTRAN IV, the program contains subroutines that were developed for Appalachian logging conditions. However, with appropriate modifications, the simulator would be applicable for most logging operations and locations. The details of model development and its methodology are presented,...

  3. Generalized environmental control and life support system computer program (G189A) configuration control. [computer subroutine libraries for shuttle orbiter analyses

    NASA Technical Reports Server (NTRS)

    Blakely, R. L.

    1973-01-01

    A G189A simulation of the shuttle orbiter EC/lSS was prepared and used to study payload support capabilities. Two master program libraries of the G189A computer program were prepared for the NASA/JSC computer system. Several new component subroutines were added to the G189A program library and many existing subroutines were revised to improve their capabilities. A number of special analyses were performed in support of a NASA/JSC shuttle orbiter EC/LSS payload support capability study.

  4. Evaluation of the discrete vortex wake cross flow model using vector computers. Part 2: User's manual for DIVORCE

    NASA Technical Reports Server (NTRS)

    Deffenbaugh, F. D.; Vitz, J. F.

    1979-01-01

    The users manual for the Discrete Vortex Cross flow Evaluator (DIVORCE) computer program is presented. DIVORCE was developed in FORTRAN 4 for the DCD 6600 and CDC 7600 machines. Optimal calls to a NASA vector subroutine package are provided for use with the CDC 7600.

  5. The pEst version 2.1 user's manual

    NASA Technical Reports Server (NTRS)

    Murray, James E.; Maine, Richard E.

    1987-01-01

    This report is a user's manual for version 2.1 of pEst, a FORTRAN 77 computer program for interactive parameter estimation in nonlinear dynamic systems. The pEst program allows the user complete generality in definig the nonlinear equations of motion used in the analysis. The equations of motion are specified by a set of FORTRAN subroutines; a set of routines for a general aircraft model is supplied with the program and is described in the report. The report also briefly discusses the scope of the parameter estimation problem the program addresses. The report gives detailed explanations of the purpose and usage of all available program commands and a description of the computational algorithms used in the program.

  6. Multiscale Concrete Modeling of Aging Degradation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hammi, Yousseff; Gullett, Philipp; Horstemeyer, Mark F.

    In this work a numerical finite element framework is implemented to enable the integration of coupled multiscale and multiphysics transport processes. A User Element subroutine (UEL) in Abaqus is used to simultaneously solve stress equilibrium, heat conduction, and multiple diffusion equations for 2D and 3D linear and quadratic elements. Transport processes in concrete structures and their degradation mechanisms are presented along with the discretization of the governing equations. The multiphysics modeling framework is theoretically extended to the linear elastic fracture mechanics (LEFM) by introducing the eXtended Finite Element Method (XFEM) and based on the XFEM user element implementation of Ginermore » et al. [2009]. A damage model that takes into account the damage contribution from the different degradation mechanisms is theoretically developed. The total contribution of damage is forwarded to a Multi-Stage Fatigue (MSF) model to enable the assessment of the fatigue life and the deterioration of reinforced concrete structures in a nuclear power plant. Finally, two examples are presented to illustrate the developed multiphysics user element implementation and the XFEM implementation of Giner et al. [2009].« less

  7. Calibrating the Abaqus Crushable Foam Material Model using UNM Data

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Schembri, Philip E.; Lewis, Matthew W.

    Triaxial test data from the University of New Mexico and uniaxial test data from W-14 is used to calibrate the Abaqus crushable foam material model to represent the syntactic foam comprised of APO-BMI matrix and carbon microballoons used in the W76. The material model is an elasto-plasticity model in which the yield strength depends on pressure. Both the elastic properties and the yield stress are estimated by fitting a line to the elastic region of each test response. The model parameters are fit to the data (in a non-rigorous way) to provide both a conservative and not-conservative material model. Themore » model is verified to perform as intended by comparing the values of pressure and shear stress at yield, as well as the shear and volumetric stress-strain response, to the test data.« less

  8. 3D Progressive Damage Modeling for Laminated Composite Based on Crack Band Theory and Continuum Damage Mechanics

    NASA Technical Reports Server (NTRS)

    Wang, John T.; Pineda, Evan J.; Ranatunga, Vipul; Smeltzer, Stanley S.

    2015-01-01

    A simple continuum damage mechanics (CDM) based 3D progressive damage analysis (PDA) tool for laminated composites was developed and implemented as a user defined material subroutine to link with a commercially available explicit finite element code. This PDA tool uses linear lamina properties from standard tests, predicts damage initiation with an easy-to-implement Hashin-Rotem failure criteria, and in the damage evolution phase, evaluates the degradation of material properties based on the crack band theory and traction-separation cohesive laws. It follows Matzenmiller et al.'s formulation to incorporate the degrading material properties into the damaged stiffness matrix. Since nonlinear shear and matrix stress-strain relations are not implemented, correction factors are used for slowing the reduction of the damaged shear stiffness terms to reflect the effect of these nonlinearities on the laminate strength predictions. This CDM based PDA tool is implemented as a user defined material (VUMAT) to link with the Abaqus/Explicit code. Strength predictions obtained, using this VUMAT, are correlated with test data for a set of notched specimens under tension and compression loads.

  9. Steady, oscillatory, and unsteady subsonic Aerodynamics, production version 1.1 (SOUSSA-P1.1). Volume 2: User/programmer manual

    NASA Technical Reports Server (NTRS)

    Smolka, S. A.; Preuss, R. D.; Tseng, K.; Morino, L.

    1980-01-01

    A user/programmer manual for the computer program SOUSSA P 1.1 is presented. The program was designed to provide accurate and efficient evaluation of steady and unsteady loads on aircraft having arbitrary shapes and motions, including structural deformations. These design goals were in part achieved through the incorporation of the data handling capabilities of the SPAR finite element Structural Analysis computer program. As a further result, SOUSSA P possesses an extensive checkpoint/ restart facility. The programmer's portion of this manual includes overlay/subroutine hierarchy, logical flow of control, definition of SOUSSA P 1.1 FORTRAN variables, and definition of SOUSSA P 1.1 subroutines. Purpose of the SOUSSA P 1.1 modules, input data to the program, output of the program, hardware/software requirements, error detection and reporting capabilities, job control statements, a summary of the procedure for running the program and two test cases including input and output and listings are described in the user oriented portion of the manual.

  10. Investigation of the stress distribution around a mode 1 crack with a novel strain gradient theory

    NASA Astrophysics Data System (ADS)

    Lederer, M.; Khatibi, G.

    2017-01-01

    Stress concentrations at the tip of a sharp crack have extensively been investigated in the past century. According to the calculations of Inglis, the stress ahead of a mode 1 crack shows the characteristics of a singularity. This solution is exact in the framework of linear elastic fracture mechanics (LEFM). From the viewpoint of multiscale modelling, however, it is evident that the stress at the tip of a stable crack cannot be infinite, because the strengths of atomic bonds are finite. In order to prevent the problem of this singularity, a new version of strain gradient elasticity is employed here. This theory is implemented in the commercial FEM code ABAQUS through user subroutine UEL. Convergence of the model is proved through consecutive mesh refinement. In consequence, the stresses ahead of a mode 1 crack become finite. Furthermore, the model predicts a size effect in the sense “smaller is stronger”.

  11. Left Ventricular Endocardium Tracking by Fusion of Biomechanical and Deformable Models

    PubMed Central

    Gu, Jason

    2014-01-01

    This paper presents a framework for tracking left ventricular (LV) endocardium through 2D echocardiography image sequence. The framework is based on fusion of biomechanical (BM) model of the heart with the parametric deformable model. The BM model constitutive equation consists of passive and active strain energy functions. The deformations of the LV are obtained by solving the constitutive equations using ABAQUS FEM in each frame in the cardiac cycle. The strain energy functions are defined in two user subroutines for active and passive phases. Average fusion technique is used to fuse the BM and deformable model contours. Experimental results are conducted to verify the detected contours and the results are evaluated by comparing themto a created gold standard. The results and the evaluation proved that the framework has the tremendous potential to track and segment the LV through the whole cardiac cycle. PMID:24587814

  12. The inverse of winnowing: a FORTRAN subroutine and discussion of unwinnowing discrete data

    USGS Publications Warehouse

    Bracken, Robert E.

    2004-01-01

    This report describes an unwinnowing algorithm that utilizes a discrete Fourier transform, and a resulting Fortran subroutine that winnows or unwinnows a 1-dimensional stream of discrete data; the source code is included. The unwinnowing algorithm effectively increases (by integral factors) the number of available data points while maintaining the original frequency spectrum of a data stream. This has utility when an increased data density is required together with an availability of higher order derivatives that honor the original data.

  13. Modeling viscoelastic deformation of the earth due to surface loading by commercial finite element package - ABAQUS

    NASA Astrophysics Data System (ADS)

    Kit Wong, Ching; Wu, Patrick

    2017-04-01

    Wu (2004) developed a transformation scheme to model viscoelatic deformation due to glacial loading by commercial finite element package - ABAQUS. Benchmark tests confirmed that this method works extremely well on incompressible earth model. Bangtsson & Lund (2008),however, showed that the transformation scheme would lead to incorrect results if compressible material parameters are used. Their study implies that Wu's method of stress transformation is inadequate to model the load induced deformation of a compressible earth under the framework of ABAQUS. In light of this, numerical experiments are carried out to find if there exist other methods that serve this purpose. All the tested methods are not satisfying as the results failed to converge through iterations, except at the elastic limit. Those tested methods will be outlined and the results will be presented. Possible reasons of failure will also be discussed. Bängtsson, E., & Lund, B. (2008). A comparison between two solution techniques to solve the equations of glacially induced deformation of an elastic Earth. International journal for numerical methods in engineering, 75(4), 479-502. Wu, P. (2004). Using commercial finite element packages for the study of earth deformations, sea levels and the state of stress. Geophysical Journal International, 158(2), 401-408.

  14. Scalable Computing of the Mesh Size Effect on Modeling Damage Mechanics in Woven Armor Composites

    DTIC Science & Technology

    2008-12-01

    manner of a user defined material subroutine to provide overall stress increments to, the parallel LS-DYNA3D a Lagrangian explicit code used in...finite element code, as a user defined material subroutine . The ability of this subroutine to model the effect of the progressions of a select number...is added as a user defined material subroutine to parallel LS-DYNA3D. The computations of the global mesh are handled by LS-DYNA3D and are spread

  15. DESAP 1: A structural design program with stress and displacement constraints. Volume 1: Theoretical and user's manual

    NASA Technical Reports Server (NTRS)

    Kiusalaas, J.; Reddy, G. B.

    1977-01-01

    A finite element program is presented for computer-automated, minimum weight design of elastic structures with constraints on stresses (including local instability criteria) and displacements. Volume 1 of the report contains the theoretical and user's manual of the program. Sample problems and the listing of the program are included in Volumes 2 and 3. The element subroutines are organized so as to facilitate additions and changes by the user. As a result, a relatively minor programming effort would be required to make DESAP 1 into a special purpose program to handle the user's specific design requirements and failure criteria.

  16. PROCESS SIMULATION OF COLD PRESSING OF ARMSTRONG CP-Ti POWDERS

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sabau, Adrian S; Gorti, Sarma B; Peter, William H

    A computational methodology is presented for the process simulation of cold pressing of Armstrong CP-Ti Powders. The computational model was implemented in the commercial finite element program ABAQUSTM. Since the powder deformation and consolidation is governed by specific pressure-dependent constitutive equations, several solution algorithms were developed for the ABAQUS user material subroutine, UMAT. The solution algorithms were developed for computing the plastic strain increments based on an implicit integration of the nonlinear yield function, flow rule, and hardening equations that describe the evolution of the state variables. Since ABAQUS requires the use of a full Newton-Raphson algorithm for the stress-strainmore » equations, an algorithm for obtaining the tangent/linearization moduli, which is consistent with the return-mapping algorithm, also was developed. Numerical simulation results are presented for the cold compaction of the Ti powders. Several simulations were conducted for cylindrical samples with different aspect ratios. The numerical simulation results showed that for the disk samples, the minimum von Mises stress was approximately half than its maximum value. The hydrostatic stress distribution exhibits a variation smaller than that of the von Mises stress. It was found that for the disk and cylinder samples the minimum hydrostatic stresses were approximately 23 and 50% less than its maximum value, respectively. It was also found that the minimum density was noticeably affected by the sample height.« less

  17. Comparisons of node-based and element-based approaches of assigning bone material properties onto subject-specific finite element models.

    PubMed

    Chen, G; Wu, F Y; Liu, Z C; Yang, K; Cui, F

    2015-08-01

    Subject-specific finite element (FE) models can be generated from computed tomography (CT) datasets of a bone. A key step is assigning material properties automatically onto finite element models, which remains a great challenge. This paper proposes a node-based assignment approach and also compares it with the element-based approach in the literature. Both approaches were implemented using ABAQUS. The assignment procedure is divided into two steps: generating the data file of the image intensity of a bone in a MATLAB program and reading the data file into ABAQUS via user subroutines. The node-based approach assigns the material properties to each node of the finite element mesh, while the element-based approach assigns the material properties directly to each integration point of an element. Both approaches are independent from the type of elements. A number of FE meshes are tested and both give accurate solutions; comparatively the node-based approach involves less programming effort. The node-based approach is also independent from the type of analyses; it has been tested on the nonlinear analysis of a Sawbone femur. The node-based approach substantially improves the level of automation of the assignment procedure of bone material properties. It is the simplest and most powerful approach that is applicable to many types of analyses and elements. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

  18. Simulation of Weld Mechanical Behavior to Include Welding-Induced Residual Stress and Distortion: Coupling of SYSWELD and Abaqus Codes

    DTIC Science & Technology

    2015-11-01

    induced residual stresses and distortions from weld simulations in the SYSWELD software code in structural Finite Element Analysis ( FEA ) simulations...performed in the Abaqus FEA code is presented. The translation of these results is accomplished using a newly developed Python script. Full details of...Local Weld Model in Structural FEA ....................................................15 CONCLUSIONS

  19. Final report on the development of the geographic position locator (GPL). Volume 12. Data reduction A3FIX: subroutine

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Niven, W.A.

    The long-term position accuracy of an inertial navigation system depends primarily on the ability of the gyroscopes to maintain a near-perfect reference orientation. Small imperfections in the gyroscopes cause them to drift slowly away from their initial orientation, thereby producing errors in the system's calculations of position. The A3FIX is a computer program subroutine developed to estimate inertial navigation system gyro drift rates with the navigator stopped or moving slowly. It processes data of the navigation system's position error to arrive at estimates of the north- south and vertical gyro drift rates. It also computes changes in the east--west gyromore » drift rate if the navigator is stopped and if data on the system's azimuth error changes are also available. The report describes the subroutine, its capabilities, and gives examples of gyro drift rate estimates that were computed during the testing of a high quality inertial system under the PASSPORT program at the Lawrence Livermore Laboratory. The appendices provide mathematical derivations of the estimation equations that are used in the subroutine, a discussion of the estimation errors, and a program listing and flow diagram. The appendices also contain a derivation of closed form solutions to the navigation equations to clarify the effects that motion and time-varying drift rates induce in the phase-plane relationships between the Schulerfiltered errors in latitude and azimuth snd between the Schulerfiltered errors in latitude and longitude. (auth)« less

  20. Implementation of a finite element analysis procedure for structural analysis of shape memory behaviour of fibre reinforced shape memory polymer composites

    NASA Astrophysics Data System (ADS)

    Azzawi, Wessam Al; Epaarachchi, J. A.; Islam, Mainul; Leng, Jinsong

    2017-12-01

    Shape memory polymers (SMPs) offer a unique ability to undergo a substantial shape deformation and subsequently recover the original shape when exposed to a particular external stimulus. Comparatively low mechanical properties being the major drawback for extended use of SMPs in engineering applications. However the inclusion of reinforcing fibres in to SMPs improves mechanical properties significantly while retaining intrinsic shape memory effects. The implementation of shape memory polymer composites (SMPCs) in any engineering application is a unique task which requires profound materials and design optimization. However currently available analytical tools have critical limitations to undertake accurate analysis/simulations of SMPC structures and slower derestrict transformation of breakthrough research outcomes to real-life applications. Many finite element (FE) models have been presented. But majority of them require a complicated user-subroutines to integrate with standard FE software packages. Furthermore, those subroutines are problem specific and difficult to use for a wider range of SMPC materials and related structures. This paper presents a FE simulation technique to model the thermomechanical behaviour of the SMPCs using commercial FE software ABAQUS. Proposed technique incorporates material time-dependent viscoelastic behaviour. The ability of the proposed technique to predict the shape fixity and shape recovery was evaluated by experimental data acquired by a bending of a SMPC cantilever beam. The excellent correlation between the experimental and FE simulation results has confirmed the robustness of the proposed technique.

  1. Computer Program and User Documentation Medical Data Input System

    NASA Technical Reports Server (NTRS)

    Anderson, J.

    1971-01-01

    Several levels of documentation are presented for the program module of the NASA medical directorate minicomputer storage and retrieval system. The biomedical information system overview gives reasons for the development of the minicomputer storage and retrieval system. It briefly describes all of the program modules which constitute the system. A technical discussion oriented to the programmer is given. Each subroutine is described in enough detail to permit in-depth understanding of the routines and to facilitate program modifications. The program utilization section may be used as a users guide.

  2. Model and Simulation of an SMA Enhanced Lip Seal

    NASA Astrophysics Data System (ADS)

    Qiao, Rui; Gao, Xiujie; Brinson, L. Catherine

    2011-07-01

    The feasibility of using SMA wires to improve the seal effectiveness has been studied experimentally and numerically. In this article, we present only the numerical study of simulating the thermo-mechanical behavior for an SMA enhanced lip seal, leaving the test setup and results in the experimental counterpart. A pseudo 3D SMA model, considering 1D SMA behavior in the major loading direction and elastic response in other directions, was used to capture the thermo-mechanical behavior of SMA wires. The model was then implemented into ABAQUS using the user-defined material subroutine to inherit most features of the commercial finite element package. Two-way shape memory effect was also considered since the SMA material exhibits strong two-way effects. An axisymmetric finite element model was constructed to simulate a seal mounting on a shaft and the sealing pressure was calculated for both the regular seal and the SMA enhanced seal. Finally, the result was qualitatively compared with the experimental observation.

  3. Mechanical characterization and modeling of the deformation and failure of the highly crosslinked RTM6 epoxy resin

    NASA Astrophysics Data System (ADS)

    Morelle, X. P.; Chevalier, J.; Bailly, C.; Pardoen, T.; Lani, F.

    2017-08-01

    The nonlinear deformation and fracture of RTM6 epoxy resin is characterized as a function of strain rate and temperature under various loading conditions involving uniaxial tension, notched tension, uniaxial compression, torsion, and shear. The parameters of the hardening law depend on the strain-rate and temperature. The pressure-dependency and hardening law, as well as four different phenomenological failure criteria, are identified using a subset of the experimental results. Detailed fractography analysis provides insight into the competition between shear yielding and maximum principal stress driven brittle failure. The constitutive model and a stress-triaxiality dependent effective plastic strain based failure criterion are readily introduced in the standard version of Abaqus, without the need for coding user subroutines, and can thus be directly used as an input in multi-scale modeling of fibre-reinforced composite material. The model is successfully validated against data not used for the identification and through the full simulation of the crack propagation process in the V-notched beam shear test.

  4. An Implicit Algorithm for the Numerical Simulation of Shape-Memory Alloys

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Becker, R; Stolken, J; Jannetti, C

    Shape-memory alloys (SMA) have the potential to be used in a variety of interesting applications due to their unique properties of pseudoelasticity and the shape-memory effect. However, in order to design SMA devices efficiently, a physics-based constitutive model is required to accurately simulate the behavior of shape-memory alloys. The scope of this work is to extend the numerical capabilities of the SMA constitutive model developed by Jannetti et. al. (2003), to handle large-scale polycrystalline simulations. The constitutive model is implemented within the finite-element software ABAQUS/Standard using a user defined material subroutine, or UMAT. To improve the efficiency of the numericalmore » simulations, so that polycrystalline specimens of shape-memory alloys can be modeled, a fully implicit algorithm has been implemented to integrate the constitutive equations. Using an implicit integration scheme increases the efficiency of the UMAT over the previously implemented explicit integration method by a factor of more than 100 for single crystal simulations.« less

  5. Development and parameter identification of a visco-hyperelastic model for the periodontal ligament.

    PubMed

    Huang, Huixiang; Tang, Wencheng; Tan, Qiyan; Yan, Bin

    2017-04-01

    The present study developed and implemented a new visco-hyperelastic model that is capable of predicting the time-dependent biomechanical behavior of the periodontal ligament. The constitutive model has been implemented into the finite element package ABAQUS by means of a user-defined material subroutine (UMAT). The stress response is decomposed into two constitutive parts in parallel which are a hyperelastic and a time-dependent viscoelastic stress response. In order to identify the model parameters, the indentation equation based on V-W hyperelastic model and the indentation creep model are developed. Then the parameters are determined by fitting them to the corresponding nanoindentation experimental data of the PDL. The nanoindentation experiment was simulated by finite element analysis to validate the visco-hyperelastic model. The simulated results are in good agreement with the experimental data, which demonstrates that the visco-hyperelastic model developed is able to accurately predict the time-dependent mechanical behavior of the PDL. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. User Interface Technology for Formal Specification Development

    NASA Technical Reports Server (NTRS)

    Lowry, Michael; Philpot, Andrew; Pressburger, Thomas; Underwood, Ian; Lum, Henry, Jr. (Technical Monitor)

    1994-01-01

    Formal specification development and modification are an essential component of the knowledge-based software life cycle. User interface technology is needed to empower end-users to create their own formal specifications. This paper describes the advanced user interface for AMPHION1 a knowledge-based software engineering system that targets scientific subroutine libraries. AMPHION is a generic, domain-independent architecture that is specialized to an application domain through a declarative domain theory. Formal specification development and reuse is made accessible to end-users through an intuitive graphical interface that provides semantic guidance in creating diagrams denoting formal specifications in an application domain. The diagrams also serve to document the specifications. Automatic deductive program synthesis ensures that end-user specifications are correctly implemented. The tables that drive AMPHION's user interface are automatically compiled from a domain theory; portions of the interface can be customized by the end-user. The user interface facilitates formal specification development by hiding syntactic details, such as logical notation. It also turns some of the barriers for end-user specification development associated with strongly typed formal languages into active sources of guidance, without restricting advanced users. The interface is especially suited for specification modification. AMPHION has been applied to the domain of solar system kinematics through the development of a declarative domain theory. Testing over six months with planetary scientists indicates that AMPHION's interactive specification acquisition paradigm enables users to develop, modify, and reuse specifications at least an order of magnitude more rapidly than manual program development.

  7. Coupled field-structural analysis of HGTR fuel brick using ABAQUS

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Mohanty, S.; Jain, R.; Majumdar, S.

    2012-07-01

    High-temperature, gas-cooled reactors (HTGRs) are usually helium-gas cooled, with a graphite core that can operate at reactor outlet temperatures much higher than can conventional light water reactors. In HTGRs, graphite components moderate and reflect neutrons. During reactor operation, high temperature and high irradiation cause damage to the graphite crystal and grains and create other defects. This cumulative structural damage during the reactor lifetime leads to changes in graphite properties, which can alter the ability to support the designed loads. The aim of the present research is to develop a finite-element code using commercially available ABAQUS software for the structural integritymore » analysis of graphite core components under extreme temperature and irradiation conditions. In addition, the Reactor Geometry Generator tool-kit, developed at Argonne National Laboratory, is used to generate finite-element mesh for complex geometries such as fuel bricks with multiple pin holes and coolant flow channels. This paper presents the proposed concept and discusses results of stress analysis simulations of a fuel block with H-451 grade material properties. (authors)« less

  8. A three-dimensional, compressible, laminar boundary-layer method for general fuselages. Volume 2: User's manual

    NASA Technical Reports Server (NTRS)

    Wie, Yong-Sun

    1990-01-01

    This user's manual contains a complete description of the computer programs developed to calculate three-dimensional, compressible, laminar boundary layers for perfect gas flow on general fuselage shapes. These programs include the 3-D boundary layer program (3DBLC), the body-oriented coordinate program (BCC), and the streamline coordinate program (SCC). Subroutine description, input, output and sample case are discussed. The complete FORTRAN listings of the computer programs are given.

  9. MUST - An integrated system of support tools for research flight software engineering. [Multipurpose User-oriented Software Technology

    NASA Technical Reports Server (NTRS)

    Straeter, T. A.; Foudriat, E. C.; Will, R. W.

    1977-01-01

    The objectives of NASA's MUST (Multipurpose User-oriented Software Technology) program at Langley Research Center are to cut the cost of producing software which effectively utilizes digital systems for flight research. These objectives will be accomplished by providing an integrated system of support software tools for use throughout the research flight software development process. A description of the overall MUST program and its progress toward the release of a first MUST system will be presented. This release includes: a special interactive user interface, a library of subroutines, assemblers, a compiler, automatic documentation tools, and a test and simulation system.

  10. Noise produced by turbulent flow into a rotor: Users manual for noise calculation

    NASA Technical Reports Server (NTRS)

    Amiet, R. K.; Egolf, C. G.; Simonich, J. C.

    1989-01-01

    A users manual for a computer program for the calculation of noise produced by turbulent flow into a helicopter rotor is presented. These inputs to the program are obtained from the atmospheric turbulence model and mean flow distortion calculation, described in another volume of this set of reports. Descriptions of the various program modules and subroutines, their function, programming structure, and the required input and output variables are included. This routine is incorporated as one module of NASA's ROTONET helicopter noise prediction program.

  11. Design and Optimization of a Composite Canard Control Surface of an Advanced Fighter Aircraft under Static Loading

    NASA Astrophysics Data System (ADS)

    Shrivastava, Sachin; Mohite, P. M.

    2015-01-01

    The minimization of weight and maximization of payload is an ever challenging design procedure for air vehicles. The present study has been carried out with an objective to redesign control surface of an advanced all-metallic fighter aircraft. In this study, the structure made up of high strength aluminum, titanium and ferrous alloys has been attempted to replace by carbon fiber composite (CFC) skin, ribs and stiffeners. This study presents an approach towards development of a methodology for optimization of first-ply failure index (FI) in unidirectional fibrous laminates using Genetic-Algorithms (GA) under quasi-static loading. The GAs, by the application of its operators like reproduction, cross-over, mutation and elitist strategy, optimize the ply-orientations in laminates so as to have minimum FI of Tsai-Wu first-ply failure criterion. The GA optimization procedure has been implemented in MATLAB and interfaced with commercial software ABAQUS using python scripting. FI calculations have been carried out in ABAQUS with user material subroutine (UMAT). The GA's application gave reasonably well-optimized ply-orientations combination at a faster convergence rate. However, the final optimized sequence of ply-orientations is obtained by tweaking the sequences given by GA's based on industrial practices and experience, whenever needed. The present study of conversion of an all metallic structure to partial CFC structure has led to 12% of weight reduction. Therefore, the approach proposed here motivates designer to use CFC with a confidence.

  12. A Nonlinear Viscoelastic Model for Ceramics at High Temperatures

    NASA Technical Reports Server (NTRS)

    Powers, Lynn M.; Panoskaltsis, Vassilis P.; Gasparini, Dario A.; Choi, Sung R.

    2002-01-01

    High-temperature creep behavior of ceramics is characterized by nonlinear time-dependent responses, asymmetric behavior in tension and compression, and nucleation and coalescence of voids leading to creep rupture. Moreover, creep rupture experiments show considerable scatter or randomness in fatigue lives of nominally equal specimens. To capture the nonlinear, asymmetric time-dependent behavior, the standard linear viscoelastic solid model is modified. Nonlinearity and asymmetry are introduced in the volumetric components by using a nonlinear function similar to a hyperbolic sine function but modified to model asymmetry. The nonlinear viscoelastic model is implemented in an ABAQUS user material subroutine. To model the random formation and coalescence of voids, each element is assigned a failure strain sampled from a lognormal distribution. An element is deleted when its volumetric strain exceeds its failure strain. Element deletion has been implemented within ABAQUS. Temporal increases in strains produce a sequential loss of elements (a model for void nucleation and growth), which in turn leads to failure. Nonlinear viscoelastic model parameters are determined from uniaxial tensile and compressive creep experiments on silicon nitride. The model is then used to predict the deformation of four-point bending and ball-on-ring specimens. Simulation is used to predict statistical moments of creep rupture lives. Numerical simulation results compare well with results of experiments of four-point bending specimens. The analytical model is intended to be used to predict the creep rupture lives of ceramic parts in arbitrary stress conditions.

  13. RPSL1D (A One-Dimensional Version of REPSIL).

    DTIC Science & Technology

    1982-11-01

    PROGRAM FOR RPSL1D ....... ..................... 97 E . EXAMPLES ........... ............................ .105 F. SOME ALTERNATE USER SUBROUTINES...of these have been incorporated into RPSLID, as tabu- lated in Appendix C, and others discussed in Section 5 and Appendices E and F may be useful in...replace them with copies of user subroutines listed in Appendices E and F, or replace them with his own subroutines. For some particular applications it

  14. RAMONA-4B a computer code with three-dimensional neutron kinetics for BWR and SBWR system transient - user`s manual

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Rohatgi, U.S.; Cheng, H.S.; Khan, H.J.

    This document is the User`s Manual for the Boiling Water Reactor (BWR), and Simplified Boiling Water Reactor (SBWR) systems transient code RAMONA-4B. The code uses a three-dimensional neutron-kinetics model coupled with a multichannel, nonequilibrium, drift-flux, phase-flow model of the thermal hydraulics of the reactor vessel. The code is designed to analyze a wide spectrum of BWR core and system transients. Chapter 1 gives an overview of the code`s capabilities and limitations; Chapter 2 describes the code`s structure, lists major subroutines, and discusses the computer requirements. Chapter 3 is on code, auxillary codes, and instructions for running RAMONA-4B on Sun SPARCmore » and IBM Workstations. Chapter 4 contains component descriptions and detailed card-by-card input instructions. Chapter 5 provides samples of the tabulated output for the steady-state and transient calculations and discusses the plotting procedures for the steady-state and transient calculations. Three appendices contain important user and programmer information: lists of plot variables (Appendix A) listings of input deck for sample problem (Appendix B), and a description of the plotting program PAD (Appendix C). 24 refs., 18 figs., 11 tabs.« less

  15. Process Simulation of Cold Pressing and Sintering of Armstrong CP-Ti Powders

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gorti, Sarma B; Sabau, Adrian S; Peter, William H

    A computational methodology is presented for the process simulation of cold pressing and sintering of Armstrong CP-Ti powders. Since the powder consolidation is governed by specific pressure-dependent constitutive equations, solution algorithms were developed for the ABAQUS user material subroutine, UMAT, for computing the plastic strain increments based on an implicit integration of the nonlinear yield function, flow rule, and hardening equations. Sintering was simulated using a model based on diffusional creep using the user subroutine CREEP. The initial mesh, stress, and density for the simulation of sintering were obtained from the results of the cold pressing simulation, minimizing the errorsmore » from decoupling the cold pressing and sintering simulations. Numerical simulation results are presented for the cold compaction followed by a sintering step of the Ti powders. The numerical simulation results for the relative density were compared to those measured from experiments before and after sintering, showing that the relative density can be accurately predicted. Notice: This manuscript has been authored by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. ACKNOWLEDGEMENTS This research was sponsored by the U.S. DOE, and carried out at ORNL, under Contract DE-AC05-00OR22725 with UT-Battelle, LLC. This research was sponsored by the U.S. DOE, EERE Industrial Technology Program Office under CPS Agreement # 17881.« less

  16. Flight dynamics analysis and simulation of heavy lift airships, volume 4. User's guide: Appendices

    NASA Technical Reports Server (NTRS)

    Emmen, R. D.; Tischler, M. B.

    1982-01-01

    This table contains all of the input variables to the three programs. The variables are arranged according to the name list groups in which they appear in the data files. The program name, subroutine name, definition and, where appropriate, a default input value and any restrictions are listed with each variable. The default input values are user supplied, not generated by the computer. These values remove a specific effect from the calculations, as explained in the table. The phrase "not used' indicates that a variable is not used in the calculations and are for identification purposes only. The engineering symbol, where it exists, is listed to assist the user in correlating these inputs with the discussion in the Technical Manual.

  17. Variational Trajectory Optimization Tool Set: Technical description and user's manual

    NASA Technical Reports Server (NTRS)

    Bless, Robert R.; Queen, Eric M.; Cavanaugh, Michael D.; Wetzel, Todd A.; Moerder, Daniel D.

    1993-01-01

    The algorithms that comprise the Variational Trajectory Optimization Tool Set (VTOTS) package are briefly described. The VTOTS is a software package for solving nonlinear constrained optimal control problems from a wide range of engineering and scientific disciplines. The VTOTS package was specifically designed to minimize the amount of user programming; in fact, for problems that may be expressed in terms of analytical functions, the user needs only to define the problem in terms of symbolic variables. This version of the VTOTS does not support tabular data; thus, problems must be expressed in terms of analytical functions. The VTOTS package consists of two methods for solving nonlinear optimal control problems: a time-domain finite-element algorithm and a multiple shooting algorithm. These two algorithms, under the VTOTS package, may be run independently or jointly. The finite-element algorithm generates approximate solutions, whereas the shooting algorithm provides a more accurate solution to the optimization problem. A user's manual, some examples with results, and a brief description of the individual subroutines are included.

  18. The MHOST finite element program: 3-D inelastic analysis methods for hot section components. Volume 2: User's manual

    NASA Technical Reports Server (NTRS)

    Nakazawa, Shohei

    1989-01-01

    The user options available for running the MHOST finite element analysis package is described. MHOST is a solid and structural analysis program based on the mixed finite element technology, and is specifically designed for 3-D inelastic analysis. A family of 2- and 3-D continuum elements along with beam and shell structural elements can be utilized, many options are available in the constitutive equation library, the solution algorithms and the analysis capabilities. The outline of solution algorithms is discussed along with the data input and output, analysis options including the user subroutines and the definition of the finite elements implemented in the program package.

  19. Analysis of SMA Hybrid Composite Structures in MSC.Nastran and ABAQUS

    NASA Technical Reports Server (NTRS)

    Turner, Travis L.; Patel, Hemant D.

    2005-01-01

    A thermoelastic constitutive model for shape memory alloy (SMA) actuators and SMA hybrid composite (SMAHC) structures was recently implemented in the commercial finite element codes MSC.Nastran and ABAQUS. The model may be easily implemented in any code that has the capability for analysis of laminated composite structures with temperature dependent material properties. The model is also relatively easy to use and requires input of only fundamental engineering properties. A brief description of the model is presented, followed by discussion of implementation and usage in the commercial codes. Results are presented from static and dynamic analysis of SMAHC beams of two types; a beam clamped at each end and a cantilever beam. Nonlinear static (post-buckling) and random response analyses are demonstrated for the first specimen. Static deflection (shape) control is demonstrated for the cantilever beam. Approaches for modeling SMAHC material systems with embedded SMA in ribbon and small round wire product forms are demonstrated and compared. The results from the commercial codes are compared to those from a research code as validation of the commercial implementations; excellent correlation is achieved in all cases.

  20. DAMAGE MODELING OF INJECTION-MOLDED SHORT- AND LONG-FIBER THERMOPLASTICS

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Nguyen, Ba Nghiep; Kunc, Vlastimil; Bapanapalli, Satish K.

    2009-10-30

    This article applies the recent anisotropic rotary diffusion – reduced strain closure (ARD-RSC) model for predicting fiber orientation and a new damage model for injection-molded long-fiber thermoplastics (LFTs) to analyze progressive damage leading to total failure of injection-molded long-glass-fiber/polypropylene (PP) specimens. The ARD-RSC model was implemented in a research version of the Autodesk Moldflow Plastics Insight (MPI) processing code, and it has been used to simulate injection-molding of a long-glass-fiber/PP plaque. The damage model combines micromechanical modeling with a continuum damage mechanics description to predict the nonlinear behavior due to plasticity coupled with damage in LFTs. This model has beenmore » implemented in the ABAQUS finite element code via user-subroutines and has been used in the damage analyses of tensile specimens removed from the injection-molded long-glass-fiber/PP plaques. Experimental characterization and mechanical testing were performed to provide input data to support and validate both process modeling and damage analyses. The predictions are in agreement with the experimental results.« less

  1. Experimental Study and Numerical Modelling of Low Velocity Impact on Laminated Composite Reinforced with Thin Film Made of Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    El Moumen, A.; Tarfaoui, M.; Hassoon, O.; Lafdi, K.; Benyahia, H.; Nachtane, M.

    2018-04-01

    In this work, polymer laminated composites based on Epon 862 Epoxy resin, T300 6 k carbon fibers and carbon nanotubes (CNTs) were tested with the aim to elucidate the effect of CNTs on impact properties including impact force and capacity to absorb impact energy. The polymer matrix was reinforced by a random distribution of CNTs with fraction ranging from 0.5 to 4.wt%. Composite panels were manufactured by using the infusion process. Taylor impact test was used to obtain the impact response of specimens. Projectile manufactured from a high strength and hardened steel with a diameter of 20 mm and 1.5 kg of mass was launched by a compressed gas gun within the velocity of 3 m/s. Impact force histories and absorbed energy of specimens were recorded. A numerical model was employed to simulate the impact performance. This model has been accomplished by forming a user established subroutine (VUMAT) and executing it in ABAQUS software. Finally, the effect of CNTs amount on dynamic properties of laminated composites was discussed.

  2. Parameter estimation of a nonlinear Burger's model using nanoindentation and finite element-based inverse analysis

    NASA Astrophysics Data System (ADS)

    Hamim, Salah Uddin Ahmed

    Nanoindentation involves probing a hard diamond tip into a material, where the load and the displacement experienced by the tip is recorded continuously. This load-displacement data is a direct function of material's innate stress-strain behavior. Thus, theoretically it is possible to extract mechanical properties of a material through nanoindentation. However, due to various nonlinearities associated with nanoindentation the process of interpreting load-displacement data into material properties is difficult. Although, simple elastic behavior can be characterized easily, a method to characterize complicated material behavior such as nonlinear viscoelasticity is still lacking. In this study, a nanoindentation-based material characterization technique is developed to characterize soft materials exhibiting nonlinear viscoelasticity. Nanoindentation experiment was modeled in finite element analysis software (ABAQUS), where a nonlinear viscoelastic behavior was incorporated using user-defined subroutine (UMAT). The model parameters were calibrated using a process called inverse analysis. In this study, a surrogate model-based approach was used for the inverse analysis. The different factors affecting the surrogate model performance are analyzed in order to optimize the performance with respect to the computational cost.

  3. Characteristics of shear damage for 60Sn-40Pb solder material

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Fang, H.E.; Chow, C.L.; Wei, Y.

    This paper presents an investigation of the development of a continuum damage model capable of accurately analyzing shear damage in 60Sn-40Pb solder material. Based on the theory of damage mechanics, an internal state variable known as the damage variable is introduced to characterize material degradation caused by the change of material microstructures under load. A damage surface in stress space is proposed to quantify damage initiation and its successive expanding surfaces to represent damage hardening. With the aid of irreversible thermodynamics, the damage-coupled constitutive equations and the damage evolution equations are established. A failure criterion is proposed based on themore » accumulation of overall damage in the material. The damage model is implemented in a general purpose finite element program ABAQUS through its user-defined material subroutine UMAT. The program is applied to predict shear deformation in a notched specimen. The predicted failure mode and maximum load agree well with those measured experimentally. The effect of finite element meshing on the numerical results is also examined and discussed.« less

  4. AN INVESTIGATION INTO THE MECHANICS OF SINGLE CRYSTAL TURBINE BLADES WITH A VIEW TOWARDS ENHANCING GAS TURBINE EFFICIENCY

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    K.R. Rajagopal; I.J. Rao

    The demand for increased efficiency of gas turbines used in power generation and aircraft applications has fueled research into advanced materials for gas turbine blades that can withstand higher temperatures in that they have excellent resistance to creep. The term ''Superalloys'' describes a group of alloys developed for applications that require high performance at elevated temperatures. Superalloys have a load bearing capacity up to 0.9 times their melting temperature. The objective of the investigation was to develop a thermodynamic model that can be used to describe the response of single crystal superalloys that takes into account the microstructure of themore » alloy within the context of a continuum model. Having developed the model, its efficacy was to be tested by corroborating the predictions of the model with available experimental data. Such a model was developed and it is implemented in the finite element software ABAQUS/STANDARD through a user subroutine (UMAT) so that the model can be used in realistic geometries that correspond to turbine blades.« less

  5. Probing Formability Improvement of Ultra-thin Ferritic Stainless Steel Bipolar Plate of PEMFC in Non-conventional Forming Process

    NASA Astrophysics Data System (ADS)

    Bong, Hyuk Jong; Barlat, Frédéric; Lee, Myoung-Gyu

    2016-08-01

    Formability increase in non-conventional forming profiles programmed in the servo-press was investigated using finite element analysis. As an application, forming experiment on a 0.15-mm-thick ferritic stainless steel sheet for a bipolar plate, a primary component of a proton exchange membrane fuel cell, was conducted. Four different forming profiles were considered to investigate the effects of forming profiles on formability and shape accuracy. The four motions included conventional V motion, holding motion, W motion, and oscillating motion. Among the four motions, the holding motion, in which the slide was held for a certain period at the bottom dead point, led to the best formability. Finite element simulations were conducted to validate the experimental results and to probe the formability improvement in the non-conventional forming profiles. A creep model to address stress relaxation effect along with tool elastic recovery was implemented using a user-material subroutine, CREEP in ABAQUS finite element software. The stress relaxation and variable contact conditions during the holding and oscillating profiles were found to be the main mechanism of formability improvement.

  6. Experimental and Numerical Studies on the Formability of Materials in Hot Stamping and Cold Die Quenching Processes

    NASA Astrophysics Data System (ADS)

    Li, N.; Mohamed, M. S.; Cai, J.; Lin, J.; Balint, D.; Dean, T. A.

    2011-05-01

    Formability of steel and aluminium alloys in hot stamping and cold die quenching processes is studied in this research. Viscoplastic-damage constitutive equations are developed and determined from experimental data for the prediction of viscoplastic flow and ductility of the materials. The determined unified constitutive equations are then implemented into the commercial Finite Element code Abaqus/Explicit via a user defined subroutine, VUMAT. An FE process simulation model and numerical procedures are established for the modeling of hot stamping processes for a spherical part with a central hole. Different failure modes (failure takes place either near the central hole or in the mid span of the part) are obtained. To validate the simulation results, a test programme is developed, a test die set has been designed and manufactured, and tests have been carried out for the materials with different forming rates. It has been found that very close agreements between experimental and numerical process simulation results are obtained for the ranges of temperatures and forming rates carried out.

  7. Modeling Fatigue Damage Onset and Progression in Composites Using an Element-Based Virtual Crack Closure Technique Combined With the Floating Node Method

    NASA Technical Reports Server (NTRS)

    De Carvalho, Nelson V.; Krueger, Ronald

    2016-01-01

    A new methodology is proposed to model the onset and propagation of matrix cracks and delaminations in carbon-epoxy composites subject to fatigue loading. An extended interface element, based on the Floating Node Method, is developed to represent delaminations and matrix cracks explicitly in a mesh independent fashion. Crack propagation is determined using an element-based Virtual Crack Closure Technique approach to determine mixed-mode energy release rates, and the Paris-Law relationship to obtain crack growth rate. Crack onset is determined using a stressbased onset criterion coupled with a stress vs. cycle curve and Palmgren-Miner rule to account for fatigue damage accumulation. The approach is implemented in Abaqus/Standard® via the user subroutine functionality. Verification exercises are performed to assess the accuracy and correct implementation of the approach. Finally, it was demonstrated that this approach captured the differences in failure morphology in fatigue for two laminates of identical stiffness, but with layups containing ?deg plies that were either stacked in a single group, or distributed through the laminate thickness.

  8. Prediction of fracture initiation in square cup drawing of DP980 using an anisotropic ductile fracture criterion

    NASA Astrophysics Data System (ADS)

    Park, N.; Huh, H.; Yoon, J. W.

    2017-09-01

    This paper deals with the prediction of fracture initiation in square cup drawing of DP980 steel sheet with the thickness of 1.2 mm. In an attempt to consider the influence of material anisotropy on the fracture initiation, an uncoupled anisotropic ductile fracture criterion is developed based on the Lou—Huh ductile fracture criterion. Tensile tests are carried out at different loading directions of 0°, 45°, and 90° to the rolling direction of the sheet using various specimen geometries including pure shear, dog-bone, and flat grooved specimens so as to calibrate the parameters of the proposed fracture criterion. Equivalent plastic strain distribution on the specimen surface is computed using Digital Image Correlation (DIC) method until surface crack initiates. The proposed fracture criterion is implemented into the commercial finite element code ABAQUS/Explicit by developing the Vectorized User-defined MATerial (VUMAT) subroutine which features the non-associated flow rule. Simulation results of the square cup drawing test clearly show that the proposed fracture criterion is capable of predicting the fracture initiation with sufficient accuracy considering the material anisotropy.

  9. Development of an Improved Irrigation Subroutine in SWAT to Simulate the Hydrology of Rice Paddy Grown under Submerged Conditions

    NASA Astrophysics Data System (ADS)

    Muraleedharan, B. V.; Kathirvel, K.; Narasimhan, B.; Nallasamy, N. D.

    2014-12-01

    Soil Water Assessment Tool (SWAT) is a basin scale, distributed hydrological model commonly used to predict the effect of management decisions on the hydrologic response of watersheds. Hydrologic response is decided by the various components of water balance. In the case of watersheds located in south India as well as in several other tropical countries around the world, paddy is one of the dominant crop controlling the hydrologic response of a watershed. Hence, the suitability of SWAT in replicating the hydrology of paddy fields needs to be verified. Rice paddy fields are subjected to flooding method of irrigation, while the irrigation subroutines in SWAT are developed to simulate crops grown under non flooding conditions. Moreover irrigation is represented well in field scale models, while it is poorly represented within watershed models like SWAT. Reliable simulation of flooding method of irrigation and hydrology of the fields will assist in effective water resources management of rice paddy fields which are one of the major consumers of surface and ground water resources. The current study attempts to modify the irrigation subroutine in SWAT so as to simulate flooded irrigation condition. A field water balance study was conducted on representative fields located within Gadana, a subbasin located in Tamil Nadu (southern part of India) and dominated by rice paddy based irrigation systems. The water balance of irrigated paddy fields simulated with SWAT was compared with the water balance derived by rice paddy based crop growth model named ORYZA. The variation in water levels along with the soil moisture variation predicted by SWAT was evaluated with respect to the estimates derived from ORYZA. The water levels were further validated with field based water balance measurements taken on a daily scale. It was observed that the modified irrigation subroutine was able to simulate irrigation of rice paddy within SWAT in a realistic way compared to the existing method.

  10. Computer program development and user's manual for program PARACH. [to investigate parachute spent solid rocket booster during terminal descent

    NASA Technical Reports Server (NTRS)

    Murphree, H. I.

    1979-01-01

    A user's manual is provided for program PARACH, a FORTRAN digital computer program operational on the Univac 1108. A description of the program and operating instructions for it are included. Program PARACH is used to study the interaction dynamics of a parachute and its payload during terminal descent. Operating instructions, required input data, program options and limitations, and output data are described. Subroutines used in this program are also listed and explained.

  11. A User’s/Programmer’s Manual for TWAKE.

    DTIC Science & Technology

    1988-05-06

    subroutines sorted according to primary function Inout OutDut Utjiitv Ean. Solve LDDOEL CALORD GETBAT ASSMAT EDATA COMOC LINKI ASMSQ BDINPT DRVBUG LINK2 BANCHO...beginning at the left most node (no. 1) and continuing to the last node in that row (no. 19). IBORD LEFT 2 BOTTOM 2 RIGHT 2 TOP 2 DONE LINKI 2 T call...LINK1 3 T GEOMFL Call SUBROUTINE NODELM again to compute element thickness and area from data calculated in GEOMFL. LINKI 2 T NODELM Call SUBROUTINE

  12. Tooth fracture risk analysis based on a new finite element dental structure models using micro-CT data.

    PubMed

    Chen, G; Fan, W; Mishra, S; El-Atem, A; Schuetz, M A; Xiao, Y

    2012-10-01

    The finite element (FE) analysis is an effective method to study the strength and predict the fracture risk of endodontically-treated teeth. This paper presents a rapid method developed to generate a comprehensive tooth FE model using data retrieved from micro-computed tomography (μCT). With this method, the inhomogeneity of material properties of teeth was included into the model without dividing the tooth model into different regions. The material properties of the tooth were assumed to be related to the mineral density. The fracture risk at different tooth portions was assessed for root canal treatments. The micro-CT images of a tooth were processed by a Matlab software programme and the CT numbers were retrieved. The tooth contours were obtained with thresholding segmentation using Amira. The inner and outer surfaces of the tooth were imported into Solidworks and a three-dimensional (3D) tooth model was constructed. An assembly of the tooth model with the periodontal ligament (PDL) layer and surrounding bone was imported into ABAQUS. The material properties of the tooth were calculated from the retrieved CT numbers via ABAQUS user's subroutines. Three root canal geometries (original and two enlargements) were investigated. The proposed method in this study can generate detailed 3D finite element models of a tooth with different root canal enlargements and filling materials, and would be very useful for the assessment of the fracture risk at different tooth portions after root canal treatments. Crown Copyright © 2012. Published by Elsevier Ltd. All rights reserved.

  13. Automated Reuse of Scientific Subroutine Libraries through Deductive Synthesis

    NASA Technical Reports Server (NTRS)

    Lowry, Michael R.; Pressburger, Thomas; VanBaalen, Jeffrey; Roach, Steven

    1997-01-01

    Systematic software construction offers the potential of elevating software engineering from an art-form to an engineering discipline. The desired result is more predictable software development leading to better quality and more maintainable software. However, the overhead costs associated with the formalisms, mathematics, and methods of systematic software construction have largely precluded their adoption in real-world software development. In fact, many mainstream software development organizations, such as Microsoft, still maintain a predominantly oral culture for software development projects; which is far removed from a formalism-based culture for software development. An exception is the limited domain of safety-critical software, where the high-assuiance inherent in systematic software construction justifies the additional cost. We believe that systematic software construction will only be adopted by mainstream software development organization when the overhead costs have been greatly reduced. Two approaches to cost mitigation are reuse (amortizing costs over many applications) and automation. For the last four years, NASA Ames has funded the Amphion project, whose objective is to automate software reuse through techniques from systematic software construction. In particular, deductive program synthesis (i.e., program extraction from proofs) is used to derive a composition of software components (e.g., subroutines) that correctly implements a specification. The construction of reuse libraries of software components is the standard software engineering solution for improving software development productivity and quality.

  14. Modelling multiple cycles of static and dynamic recrystallisation using a fully implicit isotropic material model based on dislocation density

    NASA Astrophysics Data System (ADS)

    Jansen van Rensburg, Gerhardus J.; Kok, Schalk; Wilke, Daniel N.

    2018-03-01

    This paper presents the development and numerical implementation of a state variable based thermomechanical material model, intended for use within a fully implicit finite element formulation. Plastic hardening, thermal recovery and multiple cycles of recrystallisation can be tracked for single peak as well as multiple peak recrystallisation response. The numerical implementation of the state variable model extends on a J2 isotropic hypo-elastoplastic modelling framework. The complete numerical implementation is presented as an Abaqus UMAT and linked subroutines. Implementation is discussed with detailed explanation of the derivation and use of various sensitivities, internal state variable management and multiple recrystallisation cycle contributions. A flow chart explaining the proposed numerical implementation is provided as well as verification on the convergence of the material subroutine. The material model is characterised using two high temperature data sets for cobalt and copper. The results of finite element analyses using the material parameter values characterised on the copper data set are also presented.

  15. Environmental application of remote sensing methods to coastal zone land use and marine resource management. Appendix F: User's guide for advection, convection prototype. [southeastern Virginia

    NASA Technical Reports Server (NTRS)

    1972-01-01

    A user's manual is provided for the environmental computer model proposed for the Richmond-Cape Henry Environmental Laboratory (RICHEL) application project for coastal zone land use investigations and marine resources management. The model was developed around the hydrologic cycle and includes two data bases consisting of climate and land use variables. The main program is described, along with control parameters to be set and pertinent subroutines.

  16. SMARTSware for SMARTS users to facilitate data reduction and data analysis

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    2005-01-01

    The software package SMARTSware is made by one of the instrument scientist on the engineering neutron diffractometer SMARTS at the Lujan Center, a national user facility at Los Alamos Neutron Scattering Center (LANSCE). The purpose of the software is to facilitate the data analysis of powder diffraction data recorded at the Lujan Center, and hence the target audience is users performing experiments at the one of the powder diffractometers (SMARTS, HIPPO, HIPD and NPDF) at the Lujan Center. The beam time at the Lujan Center is allocated by peer review of internally and extenally submitted proposals, and therefore many ofmore » the users who are granted beam time are from the international science community. Generally, the users are only at the Lujan Center for a short period of time while they are performing the experiments, and often they leave with several data sets that have not been analyzed. The distribution of the SMARTSware software package will minimize their efforts when analyzing the data once they are back at their institution. Description of software: There are two main parts of the software; a part used to generate instrument parameter files from a set of calibration runs (Smartslparm, SmartsBin, SmartsFitDif and SmartsFitspec); and a part that facilitates the batch refinement of multiple diffraction patterns (SmartsRunRep, SmartsABC, SmartsSPF and SmartsExtract). The former part may only be peripheral to most users, but is a critical part of the instrument scientists' efforts in calibrating their instruments. The latter part is highly applicable to the users as they often need to analyze or re-analyze large sets of data. The programs within the SMARTSware package heavily rely on GSAS for the Rietveld and single peak refinements of diffraction data. GSAS (General Structure Analysis System) is a public available software also originating from LANL. Subroutines and libraries from the NeXus project (a world wide trust to standardize diffraction data

  17. Fortran programs for reliability analysis

    Treesearch

    John J. Zahn

    1992-01-01

    This report contains a set of FORTRAN subroutines written to calculate the Hasofer-Lind reliability index. Nonlinear failure criteria and correlated basic variables are permitted. Users may incorporate these routines into their own calling program (an example program, RELANAL, is included) and must provide a failure criterion subroutine (two example subroutines,...

  18. User's manual for Axisymmetric Diffuser Duct (ADD) code. Volume 1: General ADD code description

    NASA Technical Reports Server (NTRS)

    Anderson, O. L.; Hankins, G. B., Jr.; Edwards, D. E.

    1982-01-01

    This User's Manual contains a complete description of the computer codes known as the AXISYMMETRIC DIFFUSER DUCT code or ADD code. It includes a list of references which describe the formulation of the ADD code and comparisons of calculation with experimental flows. The input/output and general use of the code is described in the first volume. The second volume contains a detailed description of the code including the global structure of the code, list of FORTRAN variables, and descriptions of the subroutines. The third volume contains a detailed description of the CODUCT code which generates coordinate systems for arbitrary axisymmetric ducts.

  19. Computer-Aided Structural Engineering (CASE) Project: Investigation and Design of U-Frame Structures Using Program CUFRBC. Volume C. User’s Guide for Channels

    DTIC Science & Technology

    1990-05-01

    1988) or ACI 318-83 (1983). Actual calculations for section strength are made using subroutines taken from the CASE program CSTR (Hamby and Price...validity of the design of their par- ticular structure. Thus, it is essential that the user of the program under- stand the design algorithm included...modes. However, several restrictions were placed on the design mode to avoid unnecessary com- plications of the design algorithm for cases rarely

  20. A User''s Guide to the Zwikker-Kosten Transmission Line Code (ZKTL)

    NASA Technical Reports Server (NTRS)

    Kelly, J. J.; Abu-Khajeel, H.

    1997-01-01

    This user's guide documents updates to the Zwikker-Kosten Transmission Line Code (ZKTL). This code was developed for analyzing new liner concepts developed to provide increased sound absorption. Contiguous arrays of multi-degree-of-freedom (MDOF) liner elements serve as the model for these liner configurations, and Zwikker and Kosten's theory of sound propagation in channels is used to predict the surface impedance. Transmission matrices for the various liner elements incorporate both analytical and semi-empirical methods. This allows standard matrix techniques to be employed in the code to systematically calculate the composite impedance due to the individual liner elements. The ZKTL code consists of four independent subroutines: 1. Single channel impedance calculation - linear version (SCIC) 2. Single channel impedance calculation - nonlinear version (SCICNL) 3. Multi-channel, multi-segment, multi-layer impedance calculation - linear version (MCMSML) 4. Multi-channel, multi-segment, multi-layer impedance calculation - nonlinear version (MCMSMLNL) Detailed examples, comments, and explanations for each liner impedance computation module are included. Also contained in the guide are depictions of the interactive execution, input files and output files.

  1. A hybrid modeling system designed to support decision making in the optimization of extrusion of inhomogeneous materials

    NASA Astrophysics Data System (ADS)

    Kryuchkov, D. I.; Zalazinsky, A. G.

    2017-12-01

    Mathematical models and a hybrid modeling system are developed for the implementation of the experimental-calculation method for the engineering analysis and optimization of the plastic deformation of inhomogeneous materials with the purpose of improving metal-forming processes and machines. The created software solution integrates Abaqus/CAE, a subroutine for mathematical data processing, with the use of Python libraries and the knowledge base. Practical application of the software solution is exemplified by modeling the process of extrusion of a bimetallic billet. The results of the engineering analysis and optimization of the extrusion process are shown, the material damage being monitored.

  2. Multi-Scale Process of Soil Freezing, Thawing, and Thaw-Settlement

    DTIC Science & Technology

    2013-02-18

    constitutive model was implemented into the finite element system ABAQUS using subroutine UMAT and UEXPAN to solve boundary value problems. The model...soils, 16 Int. Conf. Soil Mech. Geotech. Eng. (12 2012) 02/15/2013 13.00 Yao Zhang, Radoslaw L. Michalowski. Thermal -mechanical constitutive modeling...freezing and thawing soils…… 19 5.1 The model …………………………………………………….. 19 5.2 Thermal -mechanical load process ……………………………. 23 5.3 Implementation

  3. Programming Details for MDPLOT: A Program for Plotting Multi-Dimensional Data

    Treesearch

    W.L. Nance; B.H. Polmer; G.C. Keith

    1975-01-01

    The program is written in ASA FORTRAN IV and consists of the main program (MAIN) with 14 subroutines. Subroutines SETUP, PLOT, GRID, SCALE, and 01s are microfilm-dependent and therefore must be replaced with the equivalent routines written for the high resolution plotting device available at the user's installation. The calls to these subroutines are flagged...

  4. Crystal viscoplasticity model for the creep-fatigue interactions in single-crystal Ni-base superalloy CMSX-8

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Estrada Rodas, Ernesto A.; Neu, Richard W.

    A crystal viscoplasticity (CVP) model for the creep-fatigue interactions of nickel-base superalloy CMSX-8 is proposed. At the microstructure scale of relevance, the superalloys are a composite material comprised of a γ phase and a γ' strengthening phase with unique deformation mechanisms that are highly dependent on temperature. Considering the differences in the deformation of the individual material phases is paramount to predicting the deformation behavior of superalloys at a wide range of temperatures. In this work, we account for the relevant deformation mechanisms that take place in both material phases by utilizing two additive strain rates to model the deformationmore » on each material phase. The model is capable of representing the creep-fatigue interactions in single-crystal superalloys for realistic 3-dimensional components in an Abaqus User Material Subroutine (UMAT). Using a set of material parameters calibrated to superalloy CMSX-8, the model predicts creep-fatigue, fatigue and thermomechanical fatigue behavior of this single-crystal superalloy. In conclusion, a sensitivity study of the material parameters is done to explore the effect on the deformation due to changes in the material parameters relevant to the microstructure.« less

  5. Finite element based damage assessment of composite tidal turbine blades

    NASA Astrophysics Data System (ADS)

    Fagan, Edward M.; Leen, Sean B.; Kennedy, Ciaran R.; Goggins, Jamie

    2015-07-01

    With significant interest growing in the ocean renewables sector, horizontal axis tidal current turbines are in a position to dominate the marketplace. The test devices that have been placed in operation so far have suffered from premature failures, caused by difficulties with structural strength prediction. The goal of this work is to develop methods of predicting the damage level in tidal turbines under their maximum operating tidal velocity. The analysis was conducted using the finite element software package Abaqus; shell models of three representative tidal turbine blades are produced. Different construction methods will affect the damage level in the blade and for this study models were developed with varying hydrofoil profiles. In order to determine the risk of failure, a user material subroutine (UMAT) was created. The UMAT uses the failure criteria designed by Alfred Puck to calculate the risk of fibre and inter-fibre failure in the blades. The results show that degradation of the stiffness is predicted for the operating conditions, having an effect on the overall tip deflection. The failure criteria applied via the UMAT form a useful tool for analysis of high risk regions within the blade designs investigated.

  6. Investigation of hyperelastic models for nonlinear elastic behavior of demineralized and deproteinized bovine cortical femur bone.

    PubMed

    Hosseinzadeh, M; Ghoreishi, M; Narooei, K

    2016-06-01

    In this study, the hyperelastic models of demineralized and deproteinized bovine cortical femur bone were investigated and appropriate models were developed. Using uniaxial compression test data, the strain energy versus stretch was calculated and the appropriate hyperelastic strain energy functions were fitted on data in order to calculate the material parameters. To obtain the mechanical behavior in other loading conditions, the hyperelastic strain energy equations were investigated for pure shear and equi-biaxial tension loadings. The results showed the Mooney-Rivlin and Ogden models cannot predict the mechanical response of demineralized and deproteinized bovine cortical femur bone accurately, while the general exponential-exponential and general exponential-power law models have a good agreement with the experimental results. To investigate the sensitivity of the hyperelastic models, a variation of 10% in material parameters was performed and the results indicated an acceptable stability for the general exponential-exponential and general exponential-power law models. Finally, the uniaxial tension and compression of cortical femur bone were studied using the finite element method in VUMAT user subroutine of ABAQUS software and the computed stress-stretch curves were shown a good agreement with the experimental data. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Experimental and Numerical Analysis of Notched Composites Under Tension Loading

    NASA Astrophysics Data System (ADS)

    Aidi, Bilel; Case, Scott W.

    2015-12-01

    Experimental quasi-static tests were performed on center notched carbon fiber reinforced polymer (CFRP) composites having different stacking sequences made of G40-600/5245C prepreg. The three-dimensional Digital Image Correlation (DIC) technique was used during quasi-static tests conducted on quasi-isotropic notched samples to obtain the distribution of strains as a function of applied stress. A finite element model was built within Abaqus to predict the notched strength and the strain profiles for comparison with measured results. A user-material subroutine using the multi-continuum theory (MCT) as a failure initiation criterion and an energy-based damage evolution law as implemented by Autodesk Simulation Composite Analysis (ASCA) was used to conduct a quantitative comparison of strain components predicted by the analysis and obtained in the experiments. Good agreement between experimental data and numerical analyses results are observed. Modal analysis was carried out to investigate the effect of static damage on the dominant frequencies of the notched structure using the resulted degraded material elements. The first in-plane mode was found to be a good candidate for tracking the level of damage.

  8. Crystal viscoplasticity model for the creep-fatigue interactions in single-crystal Ni-base superalloy CMSX-8

    DOE PAGES

    Estrada Rodas, Ernesto A.; Neu, Richard W.

    2017-09-11

    A crystal viscoplasticity (CVP) model for the creep-fatigue interactions of nickel-base superalloy CMSX-8 is proposed. At the microstructure scale of relevance, the superalloys are a composite material comprised of a γ phase and a γ' strengthening phase with unique deformation mechanisms that are highly dependent on temperature. Considering the differences in the deformation of the individual material phases is paramount to predicting the deformation behavior of superalloys at a wide range of temperatures. In this work, we account for the relevant deformation mechanisms that take place in both material phases by utilizing two additive strain rates to model the deformationmore » on each material phase. The model is capable of representing the creep-fatigue interactions in single-crystal superalloys for realistic 3-dimensional components in an Abaqus User Material Subroutine (UMAT). Using a set of material parameters calibrated to superalloy CMSX-8, the model predicts creep-fatigue, fatigue and thermomechanical fatigue behavior of this single-crystal superalloy. In conclusion, a sensitivity study of the material parameters is done to explore the effect on the deformation due to changes in the material parameters relevant to the microstructure.« less

  9. UNAERO: A package of FORTRAN subroutines for approximating unsteady aerodynamics in the time domain

    NASA Technical Reports Server (NTRS)

    Dunn, H. J.

    1985-01-01

    This report serves as an instruction and maintenance manual for a collection of CDC CYBER FORTRAN IV subroutines for approximating the unsteady aerodynamic forces in the time domain. The result is a set of constant-coefficient first-order differential equations that approximate the dynamics of the vehicle. Provisions are included for adjusting the number of modes used for calculating the approximations so that an accurate approximation is generated. The number of data points at different values of reduced frequency can also be varied to adjust the accuracy of the approximation over the reduced-frequency range. The denominator coefficients of the approximation may be calculated by means of a gradient method or a least-squares approximation technique. Both the approximation methods use weights on the residual error. A new set of system equations, at a different dynamic pressure, can be generated without the approximations being recalculated.

  10. FFTDC2: a one-dimensional Fourier transform with forward and inverse data conditioning for non-complex data

    USGS Publications Warehouse

    Bracken, Robert E.

    2004-01-01

    A subroutine (FFTDC2) coded in Fortran 77 is described, which performs a Fast Fourier Transform or Discrete Fourier Transform together with necessary conditioning steps of trend removal, extension, and windowing. The source code for the entire library of required subroutines is provided with the digital release of this report. But, there is only one required entry point, the subroutine call to FFTDC2; all the other subroutines are operationally transparent to the user. Complete instructions for use of FFTDC2.F (as well as for all the other subroutines) and some practical theoretical discussions are included as comments at the beginning of the source code. This subroutine is intended to be an efficient tool for the programmer in a variety of production-level signal-processing applications.

  11. Fatigue crack growth model RANDOM2 user manual, appendix 1

    NASA Technical Reports Server (NTRS)

    Boyce, Lola; Lovelace, Thomas B.

    1989-01-01

    The FORTRAN program RANDOM2 is documented. RANDOM2 is based on fracture mechanics using a probabilistic fatigue crack growth model. It predicts the random lifetime of an engine component to reach a given crack size. Included in this user manual are details regarding the theoretical background of RANDOM2, input data, instructions and a sample problem illustrating the use of RANDOM2. Appendix A gives information on the physical quantities, their symbols, FORTRAN names, and both SI and U.S. Customary units. Appendix B includes photocopies of the actual computer printout corresponding to the sample problem. Appendices C and D detail the IMSL, Ver. 10(1), subroutines and functions called by RANDOM2 and a SAS/GRAPH(2) program that can be used to plot both the probability density function (p.d.f.) and the cumulative distribution function (c.d.f.).

  12. Micromechanics and constitutive models for soft active materials with phase evolution

    NASA Astrophysics Data System (ADS)

    Wang, Binglian

    Soft active materials, such as shape memory polymers, liquid crystal elastomers, soft tissues, gels etc., are materials that can deform largely in response to external stimuli. Micromechanics analysis of heterogeneous materials based on finite element method is a typically numerical way to study the thermal-mechanical behaviors of soft active materials with phase evolution. While the constitutive models that can precisely describe the stress and strain fields of materials in the process of phase evolution can not be found in the databases of some commercial finite element analysis (FEA) tools such as ANSYS or Abaqus, even the specific constitutive behavior for each individual phase either the new formed one or the original one has already been well-known. So developing a computationally efficient and general three dimensional (3D) thermal-mechanical constitutive model for soft active materials with phase evolution which can be implemented into FEA is eagerly demanded. This paper first solved this problem theoretically by recording the deformation history of each individual phase in the phase evolution process, and adopted the idea of effectiveness by regarding all the new formed phase as an effective phase with an effective deformation to make this theory computationally efficient. A user material subroutine (UMAT) code based on this theoretical constitutive model has been finished in this work which can be added into the material database in Abaqus or ANSYS and can be easily used for most soft active materials with phase evolution. Model validation also has been done through comparison between micromechanical FEA and experiments on a particular composite material, shape memory elastomeric composite (SMEC) which consisted of an elastomeric matrix and the crystallizable fibre. Results show that the micromechanics and the constitutive models developed in this paper for soft active materials with phase evolution are completely relied on.

  13. Nonlinear mesomechanics of composites with periodic microstructure

    NASA Technical Reports Server (NTRS)

    Walker, Kevin P.; Jordan, Eric H.; Freed, Alan D.

    1989-01-01

    This work is concerned with modeling the mechanical deformation or constitutive behavior of composites comprised of a periodic microstructure under small displacement conditions at elevated temperature. A mesomechanics approach is adopted which relates the microimechanical behavior of the heterogeneous composite with its in-service macroscopic behavior. Two different methods, one based on a Fourier series approach and the other on a Green's function approach, are used in modeling the micromechanical behavior of the composite material. Although the constitutive formulations are based on a micromechanical approach, it should be stressed that the resulting equations are volume averaged to produce overall effective constitutive relations which relate the bulk, volume averaged, stress increment to the bulk, volume averaged, strain increment. As such, they are macromodels which can be used directly in nonlinear finite element programs such as MARC, ANSYS and ABAQUS or in boundary element programs such as BEST3D. In developing the volume averaged or efective macromodels from the micromechanical models, both approaches will require the evaluation of volume integrals containing the spatially varying strain distributions throughout the composite material. By assuming that the strain distributions are spatially constant within each constituent phase-or within a given subvolume within each constituent phase-of the composite material, the volume integrals can be obtained in closed form. This simplified micromodel can then be volume averaged to obtain an effective macromodel suitable for use in the MARC, ANSYS and ABAQUS nonlinear finite element programs via user constitutive subroutines such as HYPELA and CMUSER. This effective macromodel can be used in a nonlinear finite element structural analysis to obtain the strain-temperature history at those points in the structure where thermomechanical cracking and damage are expected to occur, the so called damage critical points of

  14. nu-TRLan User Guide Version 1.0: A High-Performance Software Package for Large-Scale Harmitian Eigenvalue Problems

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Yamazaki, Ichitaro; Wu, Kesheng; Simon, Horst

    2008-10-27

    The original software package TRLan, [TRLan User Guide], page 24, implements the thick restart Lanczos method, [Wu and Simon 2001], page 24, for computing eigenvalues {lambda} and their corresponding eigenvectors v of a symmetric matrix A: Av = {lambda}v. Its effectiveness in computing the exterior eigenvalues of a large matrix has been demonstrated, [LBNL-42982], page 24. However, its performance strongly depends on the user-specified dimension of a projection subspace. If the dimension is too small, TRLan suffers from slow convergence. If it is too large, the computational and memory costs become expensive. Therefore, to balance the solution convergence and costs,more » users must select an appropriate subspace dimension for each eigenvalue problem at hand. To free users from this difficult task, nu-TRLan, [LNBL-1059E], page 23, adjusts the subspace dimension at every restart such that optimal performance in solving the eigenvalue problem is automatically obtained. This document provides a user guide to the nu-TRLan software package. The original TRLan software package was implemented in Fortran 90 to solve symmetric eigenvalue problems using static projection subspace dimensions. nu-TRLan was developed in C and extended to solve Hermitian eigenvalue problems. It can be invoked using either a static or an adaptive subspace dimension. In order to simplify its use for TRLan users, nu-TRLan has interfaces and features similar to those of TRLan: (1) Solver parameters are stored in a single data structure called trl-info, Chapter 4 [trl-info structure], page 7. (2) Most of the numerical computations are performed by BLAS, [BLAS], page 23, and LAPACK, [LAPACK], page 23, subroutines, which allow nu-TRLan to achieve optimized performance across a wide range of platforms. (3) To solve eigenvalue problems on distributed memory systems, the message passing interface (MPI), [MPI forum], page 23, is used. The rest of this document is organized as follows. In Chapter 2

  15. Documentation for subroutine REDUC3, an algorithm for the linear filtering of gridded magnetic data

    USGS Publications Warehouse

    Blakely, Richard J.

    1977-01-01

    Subroutine REDUC3 transforms a total field anomaly h1(x,y) , measured on a horizontal and rectangular grid, into a new anomaly h2(x,y). This new anomaly is produced by the same source as h1(x,y) , but (1) is observed at a different elevation, (2) has a source with a different direction of magnetization, and/or (3) has a different direction of residual field. Case 1 is tantamount to upward or downward continuation. Cases 2 and 3 are 'reduction to the pole', if the new inclinations of both the magnetization and regional field are 90 degrees. REDUC3 is a filtering operation applied in the wave-number domain. It first Fourier transforms h1(x,y) , multiplies by the appropriate filter, and inverse Fourier transforms the result to obtain h2(x,y). No assumptions are required about the shape of the source or how the intensity of magnetization varies within it.

  16. Study Orientation Ply of Fiberglass on Blade Salt Water Pump Windmill using Abaqus

    NASA Astrophysics Data System (ADS)

    Badruzzaman, B.; Sifa, A.

    2018-02-01

    Windmill is one tool to generate energy from wind energy is converted into energy motion, salt production process still using traditional process by utilizing windmill to move sea water to salt field With a windmill driven water system, a horizontal axis type windmill with an average windmill height of 3-4 m, with a potential wind speed of 5-9 m / s, the amount of blade used for salt water pumps as much as 4 blades, one of the main factor of the windmill component is a blade, blade designed for the needs of a salt water pump by using fiberglass material. On layer orientation 0°,30°,45°,60° and 90° with layer number 10 and layer thickness 2 mm, the purpose of this study was to determine the strength of fiberglass that was influenced by the orientation of the layer, and to determine the orientation of fiberglass layer before making. This method used Finite Element Analysis method using ABAQUS, with homogenous and heterogeneous layer parameters. The simulation result shows the difference in von misses value at an angle of 0°, 30°, 45°,60° homogeneous value is greater than heterogeneous value, whereas in orientation 90 heterogeneous values have value 1,689e9 Pa, greater than homogenous 90 orientation value of 1,296e9 Pa.

  17. SURFACE CHEMKIN-III: A Fortran package for analyzing heterogeneous chemical kinetics at a solid-surface - gas-phase interface

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Coltrin, M.E.; Kee, R.J.; Rupley, F.M.

    1996-05-01

    This document is the user`s manual for the SURFACE CHEMKIN-III package. Together with CHEMKIN-III, this software facilitates the formation, solution, and interpretation of problems involving elementary heterogeneous and gas-phase chemical kinetics in the presence of a solid surface. The package consists of two major software components: an Interpreter and a Surface Subroutine Library. The Interpreter is a program that reads a symbolic description of a user-specified chemical reaction mechanism. One output from the Interpreter is a data file that forms a link to the Surface Subroutine Library, which is a collection of about seventy modular Fortran subroutines that may bemore » called from a user`s application code to return information on chemical production rates and thermodynamic properties. This version of SURFACE CHEMKIN-III includes many modifications to allow treatment of multi-fluid plasma systems, for example modeling the reactions of highly energetic ionic species with a surface. Optional rate expressions allow reaction rates to depend upon ion energy rather than a single thermodynamic temperature. In addition, subroutines treat temperature as an array, allowing an application code to define a different temperature for each species. This version of SURFACE CHEMKIN-III allows use of real (non-integer) stoichiometric coefficients; the reaction order with respect to species concentrations can also be specified independent of the reaction`s stoichiometric coefficients. Several different reaction mechanisms can be specified in the Interpreter input file through the new construct of multiple materials.« less

  18. A user's guide for the signal processing software for image and speech compression developed in the Communications and Signal Processing Laboratory (CSPL), version 1

    NASA Technical Reports Server (NTRS)

    Kumar, P.; Lin, F. Y.; Vaishampayan, V.; Farvardin, N.

    1986-01-01

    A complete documentation of the software developed in the Communication and Signal Processing Laboratory (CSPL) during the period of July 1985 to March 1986 is provided. Utility programs and subroutines that were developed for a user-friendly image and speech processing environment are described. Additional programs for data compression of image and speech type signals are included. Also, programs for the zero-memory and block transform quantization in the presence of channel noise are described. Finally, several routines for simulating the perfromance of image compression algorithms are included.

  19. Damage and Failure Analysis of AZ31 Alloy Sheet in Warm Stamping Processes

    NASA Astrophysics Data System (ADS)

    Zhao, P. J.; Chen, Z. H.; Dong, C. F.

    2016-07-01

    In this study, a combined experimental-numerical investigation on the failure of AZ31 Mg alloy sheet in the warm stamping process was carried out based on modified GTN damage model which integrated Yld2000 anisotropic yield criterion. The constitutive equations of material were implemented into a VUMAT subroutine for solver ABAQUS/Explicit and applied to the formability analysis of mobile phone shell. The morphology near the crack area was observed using SEM, and the anisotropic damage evolution at various temperatures was simulated. The distributions of plastic strain, damage evolution, thickness, and fracture initiation obtained from FE simulation were analyzed. The corresponding forming limit diagrams were worked out, and the comparison with the experimental data showed a good agreement.

  20. CHEMKIN2. General Gas-Phase Chemical Kinetics

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Rupley, F.M.

    1992-01-24

    CHEMKIN is a high-level tool for chemists to use to describe arbitrary gas-phase chemical reaction mechanisms and systems of governing equations. It remains, however, for the user to select and implement a solution method; this is not provided. It consists of two major components: the Interpreter and the Gas-phase Subroutine Library. The Interpreter reads a symbolic description of an arbitrary, user-specified chemical reaction mechanism. A data file is generated which forms a link to the Gas-phase Subroutine Library, a collection of about 200 modular subroutines which may be called to return thermodynamic properties, chemical production rates, derivatives of thermodynamic properties,more » derivatives of chemical production rates, or sensitivity parameters. Both single and double precision versions of CHEMKIN are included. Also provided is a set of FORTRAN subroutines for evaluating gas-phase transport properties such as thermal conductivities, viscosities, and diffusion coefficients. These properties are an important part of any computational simulation of a chemically reacting flow. The transport properties subroutines are designed to be used in conjunction with the CHEMKIN Subroutine Library. The transport properties depend on the state of the gas and on certain molecular parameters. The parameters considered are the Lennard-Jones potential well depth and collision diameter, the dipole moment, the polarizability, and the rotational relaxation collision number.« less

  1. MASTRE trajectory code update to automate flight trajectory design, performance predictions, and vehicle sizing for support of shuttle and shuttle derived vehicles: Programmers manual

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The information required by a programmer using the Minimum Hamiltonian AScent Trajectory Evaluation (MASTRE) Program is provided. This document enables the programmer to either modify the program or convert the program to computers other than the VAX computer. Documentation for each subroutine or function based on providing the definitions of the variables and a source listing are included. Questions concerning the equations, techniques, or input requirements should be answered by either the Engineering or User's manuals. Three appendices are also included which provide a listing of the Root-Sum-Square (RSS) program, a listing of subroutine names and definitions used in the MASTRE User Friendly Interface Program, and listing of the subroutine names and definitions used in the Mass Properties Program. The RSS Program is used to aid in the performance of dispersion analyses. The RSS program reads a file generated by the MASTRE Program, calculates dispersion parameters, and generates output tables and output plot files. UFI Program provides a screen user interface to aid the user in providing input to the model. The Mass Properties Program defines the mass properties data for the MASTRE program through the use of user interface software.

  2. A Universal Graph Plotting Routine.

    ERIC Educational Resources Information Center

    Bogart, Theodore F., Jr.

    1984-01-01

    Presents a programing subroutine which will create a graphical plot that occupies any number of columns specified by user and will run with versions of BASIC programming language. Illustrations of the subroutine's ability to operate successfully for three possibilities (negative values, positive values, and both positive and negative values) are…

  3. User's manual for the Heat Pipe Space Radiator design and analysis Code (HEPSPARC)

    NASA Technical Reports Server (NTRS)

    Hainley, Donald C.

    1991-01-01

    A heat pipe space radiatior code (HEPSPARC), was written for the NASA Lewis Research Center and is used for the design and analysis of a radiator that is constructed from a pumped fluid loop that transfers heat to the evaporative section of heat pipes. This manual is designed to familiarize the user with this new code and to serve as a reference for its use. This manual documents the completed work and is intended to be the first step towards verification of the HEPSPARC code. Details are furnished to provide a description of all the requirements and variables used in the design and analysis of a combined pumped loop/heat pipe radiator system. A description of the subroutines used in the program is furnished for those interested in understanding its detailed workings.

  4. Three Dimensional Forming Simulation of the Shielded Slot Plate for the MCFC Using a Ductile Fracture Criterion

    NASA Astrophysics Data System (ADS)

    Lee, C. H.; Yang, D. Y.; Lee, S. R.; Chang, I. G.; Lee, T. W.

    2011-08-01

    The shielded slot plate, which has a sheared corrugated trapezoidal pattern, is a component of the metallic bipolar plate for the molten carbonate fuel cell (MCFC). In order to increase the efficiency of the fuel cell, the unit cell of the shielded slot plate should have a relatively large upper area. Additionally, defects from the forming process should be minimized. In order to simulate the slitting process, whereby sheared corrugated patterns are formed, ductile fracture criteria based on the histories of stress and strain are employed. The user material subroutine VUMAT is employed for implementation of the material and ductile fracture criteria in the commercial FEM software ABAQUS. The variables of the ductile fracture criteria were determined by comparing the simulation results and the experimental results of the tension test and the shearing test. Parametric studies were conducted to determine the critical value of the ductile fracture criterion. Employing these ductile fracture criteria, the three dimensional forming process of the shielded slot plate was numerically simulated. The effects of the slitting process in the forming process of the shielded slot plate were analyzed through a FEM simulation and experimental studies. Finally, experiments involving microscopic and macroscopic observations were conducted to verify the numerical simulations of the 3-step forming process.

  5. Assessing the stretch-blow moulding FE simulation of PET over a large process window

    NASA Astrophysics Data System (ADS)

    Nixon, J.; Menary, G. H.; Yan, S.

    2017-10-01

    Injection stretch blow moulding has been extensively researched for numerous years and is a well-established method of forming thin-walled containers. This paper is concerned with validating the finite element analysis of the stretch-blow-moulding (SBM) process in an effort to progress the development of injection stretch blow moulding of poly(ethylene terephthalate). Extensive data was obtained experimentally over a wide process window accounting for material temperature, air flow rate and stretch-rod speed while capturing cavity pressure, stretch-rod reaction force, in-mould contact timing and material thickness distribution. This data was then used to assess the accuracy of the correlating FE simulation constructed using ABAQUS/Explicit solver and an appropriate user-defined viscoelastic material subroutine. Results reveal that the simulation was able to pick up the general trends of how the pressure, reaction force and in-mould contact timings vary with the variation in preform temperature and air flow rate. Trends in material thickness were also accurately predicted over the length of the bottle relative to the process conditions. The knowledge gained from these analyses provides insight into the mechanisms of bottle formation, subsequently improving the blow moulding simulation and potentially providing a reduction in production costs.

  6. Penalty-Based Interface Technology for Prediction of Delamination Growth in Laminated Structures

    NASA Technical Reports Server (NTRS)

    Averill, Ronald C.

    2004-01-01

    An effective interface element technology has been developed for connecting and simulating crack growth between independently modeled finite element subdomains (e.g., composite plies). This method has been developed using penalty constraints and allows coupling of finite element models whose nodes do not necessarily coincide along their common interface. Additionally, the present formulation leads to a computational approach that is very efficient and completely compatible with existing commercial software. The present interface element has been implemented in the commercial finite element code ABAQUS as a User Element Subroutine (UEL), making it easy to test the approach for a wide range of problems. The interface element technology has been formulated to simulate delamination growth in composite laminates. Thanks to its special features, the interface element approach makes it possible to release portions of the interface surface whose length is smaller than that of the finite elements. In addition, the penalty parameter can vary within the interface element, allowing the damage model to be applied to a desired fraction of the interface between the two meshes. Results for double cantilever beam DCB, end-loaded split (ELS) and fixed-ratio mixed mode (FRMM) specimens are presented. These results are compared to measured data to assess the ability of the present damage model to simulate crack growth.

  7. Characteristics of Creep Damage for 60Sn-40Pb Solder Material

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wei, Y.; Chow, C.L.; Fang, H.E.

    This paper presents a viscoplasticity model taking into account the effects of change in grain or phase size and damage on the characterization of creep damage in 60Sn-40Pb solder. Based on the theory of damage mechanics, a two-scalar damage model is developed for isotropic materials by introducing the free energy equivalence principle. The damage evolution equations are derived in terms of the damage energy release rates. In addition, a failure criterion is developed based on the postulation that a material element is said to have ruptured when the total damage accumulated in the element reaches a critical value. The damagemore » coupled viscoplasticity model is discretized and coded in a general-purpose finite element program known as ABAQUS through its user-defined material subroutine UMAT. To illustrate the application of the model, several example cases are introduced to analyze, both numerically and experimentally, the tensile creep behaviors of the material at three stress levels. The model is then applied to predict the deformation of a notched specimen under monotonic tension at room temperature (22 C). The results demonstrate that the proposed model can successfully predict the viscoplastic behavior of the solder material.« less

  8. Application of activated barrier hopping theory to viscoplastic modeling of glassy polymers

    NASA Astrophysics Data System (ADS)

    Sweeney, J.; Spencer, P. E.; Vgenopoulos, D.; Babenko, M.; Boutenel, F.; Caton-Rose, P.; Coates, P. D.

    2018-05-01

    An established statistical mechanical theory of amorphous polymer deformation has been incorporated as a plastic mechanism into a constitutive model and applied to a range of polymer mechanical deformations. The temperature and rate dependence of the tensile yield of PVC, as reported in early studies, has been modeled to high levels of accuracy. Tensile experiments on PET reported here are analyzed similarly and good accuracy is also achieved. The frequently observed increase in the gradient of the plot of yield stress against logarithm of strain rate is an inherent feature of the constitutive model. The form of temperature dependence of the yield that is predicted by the model is found to give an accurate representation. The constitutive model is developed in two-dimensional form and implemented as a user-defined subroutine in the finite element package ABAQUS. This analysis is applied to the tensile experiments on PET, in some of which strain is localized in the form of shear bands and necks. These deformations are modeled with partial success, though adiabatic heating of the instability causes inaccuracies for this isothermal implementation of the model. The plastic mechanism has advantages over the Eyring process, is equally tractable, and presents no particular difficulties in implementation with finite elements.

  9. Thermo-Mechanical Analysis of a Single-Pass Weld Overlay and Girth Welding in Lined Pipe

    NASA Astrophysics Data System (ADS)

    Obeid, Obeid; Alfano, Giulio; Bahai, Hamid

    2017-08-01

    The paper presents a nonlinear heat-transfer and mechanical finite-element (FE) analyses of a two-pass welding process of two segments of lined pipe made of a SUS304 stainless steel liner and a C-Mn steel pipe. The two passes consist of the single-pass overlay welding (inner lap weld) of the liner with the C-Mn steel pipe for each segment and the single-pass girth welding (outer butt weld) of the two segments. A distributed power density of the moving welding torch and a nonlinear heat-transfer coefficient accounting for both radiation and convection have been used in the analysis and implemented in user subroutines for the FE code ABAQUS. The modeling procedure has been validated against previously published experimental results for stainless steel and carbon steel welding separately. The model has been then used to determine the isotherms induced by the weld overlay and the girth welding and to clarify their influence on the transient temperature field and residual stress in the lined pipe. Furthermore, the influence of the cooling time between weld overlay and girth welding and of the welding speed have been examined thermally and mechanically as they are key factors that can affect the quality of lined pipe welding.

  10. Application of activated barrier hopping theory to viscoplastic modeling of glassy polymers

    NASA Astrophysics Data System (ADS)

    Sweeney, J.; Spencer, P. E.; Vgenopoulos, D.; Babenko, M.; Boutenel, F.; Caton-Rose, P.; Coates, P. D.

    2017-10-01

    An established statistical mechanical theory of amorphous polymer deformation has been incorporated as a plastic mechanism into a constitutive model and applied to a range of polymer mechanical deformations. The temperature and rate dependence of the tensile yield of PVC, as reported in early studies, has been modeled to high levels of accuracy. Tensile experiments on PET reported here are analyzed similarly and good accuracy is also achieved. The frequently observed increase in the gradient of the plot of yield stress against logarithm of strain rate is an inherent feature of the constitutive model. The form of temperature dependence of the yield that is predicted by the model is found to give an accurate representation. The constitutive model is developed in two-dimensional form and implemented as a user-defined subroutine in the finite element package ABAQUS. This analysis is applied to the tensile experiments on PET, in some of which strain is localized in the form of shear bands and necks. These deformations are modeled with partial success, though adiabatic heating of the instability causes inaccuracies for this isothermal implementation of the model. The plastic mechanism has advantages over the Eyring process, is equally tractable, and presents no particular difficulties in implementation with finite elements.

  11. Thermal-mechanical-chemical responses of polymer-bonded explosives using a mesoscopic reactive model under impact loading.

    PubMed

    Wang, XinJie; Wu, YanQing; Huang, FengLei

    2017-01-05

    A mesoscopic framework is developed to quantify the thermal-mechanical-chemical responses of polymer-bonded explosive (PBX) samples under impact loading. A mesoscopic reactive model is developed for the cyclotetramethylenetetranitramine (HMX) crystal, which incorporates nonlinear elasticity, crystal plasticity, and temperature-dependent chemical reaction. The proposed model was implemented in the finite element code ABAQUS by the user subroutine VUMAT. A series of three-dimensional mesoscale models were constructed and calculated under low-strength impact loading scenarios from 100m/s to 600m/s where only the first wave transit is studied. Crystal anisotropy and microstructural heterogeneity are responsible for the nonuniform stress field and fluctuations of the stress wave front. At a critical impact velocity (≥300m/s), a chemical reaction is triggered because the temperature contributed by the volumetric and plastic works is sufficiently high. Physical quantities, including stress, temperature, and extent of reaction, are homogenized from those across the microstructure at the mesoscale to compare with macroscale measurements, which will advance the continuum-level models. The framework presented in this study has important implications in understanding hot spot ignition processes and improving predictive capabilities in energetic materials. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Progressive Damage Modeling of Durable Bonded Joint Technology

    NASA Technical Reports Server (NTRS)

    Leone, Frank A.; Davila, Carlos G.; Lin, Shih-Yung; Smeltzer, Stan; Girolamo, Donato; Ghose, Sayata; Guzman, Juan C.; McCarville, Duglas A.

    2013-01-01

    The development of durable bonded joint technology for assembling composite structures for launch vehicles is being pursued for the U.S. Space Launch System. The present work is related to the development and application of progressive damage modeling techniques to bonded joint technology applicable to a wide range of sandwich structures for a Heavy Lift Launch Vehicle. The joint designs studied in this work include a conventional composite splice joint and a NASA-patented Durable Redundant Joint. Both designs involve a honeycomb sandwich with carbon/epoxy facesheets joined with adhesively bonded doublers. Progressive damage modeling allows for the prediction of the initiation and evolution of damage. For structures that include multiple materials, the number of potential failure mechanisms that must be considered increases the complexity of the analyses. Potential failure mechanisms include fiber fracture, matrix cracking, delamination, core crushing, adhesive failure, and their interactions. The joints were modeled using Abaqus parametric finite element models, in which damage was modeled with user-written subroutines. Each ply was meshed discretely, and layers of cohesive elements were used to account for delaminations and to model the adhesive layers. Good correlation with experimental results was achieved both in terms of load-displacement history and predicted failure mechanisms.

  13. Mechanical modeling of self-expandable stent fabricated using braiding technology.

    PubMed

    Kim, Ju Hyun; Kang, Tae Jin; Yu, Woong-Ryeol

    2008-11-14

    The mechanical behavior of a stent is one of the important factors involved in ensuring its opening within arterial conduits. This study aimed to develop a mechanical model for designing self-expandable stents fabricated using braiding technology. For this purpose, a finite element model was constructed by developing a preprocessing program for the three-dimensional geometrical modeling of the braiding structure inside stents, and validated for various stents with different braiding structures. The constituent wires (Nitinol) in the braided stents were assumed to be superelastic material and their mechanical behavior was incorporated into the finite element software through a user material subroutine (VUMAT in ABAQUS) employing a one-dimensional superelastic model. For the verification of the model, several braided stents were manufactured using an automated braiding machine and characterized focusing on their compressive behavior. It was observed that the braided stents showed a hysteresis between their loading and unloading behavior when a compressive load was applied to the braided tube. Through the finite element analysis, it was concluded that the current mechanical model can appropriately predict the mechanical behavior of braided stents including such hysteretic behavior, and that the hysteresis was caused by the slippage between the constituent wires and their superelastic property.

  14. Programmers manual for a one-dimensional Lagrangian transport model

    USGS Publications Warehouse

    Schoellhamer, D.H.; Jobson, H.E.

    1986-01-01

    A one-dimensional Lagrangian transport model for simulating water-quality constituents such as temperature, dissolved oxygen , and suspended sediment in rivers is presented in this Programmers Manual. Lagrangian transport modeling techniques, the model 's subroutines, and the user-written decay-coefficient subroutine are discussed in detail. Appendices list the program codes. The Programmers Manual is intended for the model user who needs to modify code either to adapt the model to a particular need or to use reaction kinetics not provided with the model. (Author 's abstract)

  15. A program and data base for evaluating SMMR algorithms

    NASA Technical Reports Server (NTRS)

    1979-01-01

    A program (PARAM) is described which enables a user to compare the values of meteorological parameters derived from data obtained by the scanning multichannel microwave radiometer (SMMR) instrument on NIMBUS 7 with surface observations made over the ocean. The input to this program is a data base, also described, which contains the surface observations and coincident SMMR data. The evaluation of meteorological parameters using SMMR data is done by a user supplied subroutine. Instruments are given for executing the program and writing the subroutine.

  16. Targetting and guidance program documentation. [a user's manual

    NASA Technical Reports Server (NTRS)

    Harrold, E. F.; Neyhard, J. F.

    1974-01-01

    A FORTRAN computer program was developed which automatically targets two and three burn rendezvous missions and performs feedback guidance using the GUIDE algorithm. The program was designed to accept a large class of orbit specifications and to automatically choose a two or three burn mission depending upon the time alignment of the vehicle and target. The orbits may be specified as any combination of circular and elliptical orbits and may be coplanar or inclined, but must be aligned coaxially with their perigees in the same direction. The program accomplishes the required targeting by repeatedly converging successively more complex missions. It solves the coplanar impulsive version of the mission, then the finite burn coplanar mission, and finally, the full plane change mission. The GUIDE algorithm is exercised in a feedback guidance mode by taking the targeted solution and moving the vehicle state step by step ahead in time, adding acceleration and navigational errors, and reconverging from the perturbed states at fixed guidance update intervals. A program overview is presented, along with a user's guide which details input, output, and the various subroutines.

  17. Operational manual for two-dimensional transonic code TSFOIL

    NASA Technical Reports Server (NTRS)

    Stahara, S. S.

    1978-01-01

    This code solves the two-dimensional, transonic, small-disturbance equations for flow past lifting airfoils in both free air and various wind-tunnel environments by using a variant of the finite-difference method. A description of the theoretical and numerical basis of the code is provided, together with complete operating instructions and sample cases for the general user. In addition, a programmer's manual is also presented to assist the user interested in modifying the code. Included in the programmer's manual are a dictionary of subroutine variables in common and a detailed description of each subroutine.

  18. Study of a fail-safe abort system for an actively cooled hypersonic aircraft: Computer program documentation

    NASA Technical Reports Server (NTRS)

    Haas, L. A., Sr.

    1976-01-01

    The Fail-Safe Abort System TEMPerature Analysis Program, (FASTEMP), user's manual is presented. This program was used to analyze fail-safe abort systems for an actively cooled hypersonic aircraft. FASTEMP analyzes the steady state or transient temperature response of a thermal model defined in rectangular, cylindrical, conical and/or spherical coordinate system. FASTEMP provides the user with a large selection of subroutines for heat transfer calculations. The various modes of heat transfer available from these subroutines are: heat storage, conduction, radiation, heat addition or generation, convection, and fluid flow.

  19. Fatigue strength reduction model: RANDOM3 and RANDOM4 user manual, appendix 2

    NASA Technical Reports Server (NTRS)

    Boyce, Lola; Lovelace, Thomas B.

    1989-01-01

    The FORTRAN programs RANDOM3 and RANDOM4 are documented. They are based on fatigue strength reduction, using a probabilistic constitutive model. They predict the random lifetime of an engine component to reach a given fatigue strength. Included in this user manual are details regarding the theoretical backgrounds of RANDOM3 and RANDOM4. Appendix A gives information on the physical quantities, their symbols, FORTRAN names, and both SI and U.S. Customary units. Appendix B and C include photocopies of the actual computer printout corresponding to the sample problems. Appendices D and E detail the IMSL, Version 10(1), subroutines and functions called by RANDOM3 and RANDOM4 and SAS/GRAPH(2) programs that can be used to plot both the probability density functions (p.d.f.) and the cumulative distribution functions (c.d.f.).

  20. Accelerator System Model (ASM) user manual with physics and engineering model documentation. ASM version 1.0

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    NONE

    1993-07-01

    The Accelerator System Model (ASM) is a computer program developed to model proton radiofrequency accelerators and to carry out system level trade studies. The ASM FORTRAN subroutines are incorporated into an intuitive graphical user interface which provides for the {open_quotes}construction{close_quotes} of the accelerator in a window on the computer screen. The interface is based on the Shell for Particle Accelerator Related Codes (SPARC) software technology written for the Macintosh operating system in the C programming language. This User Manual describes the operation and use of the ASM application within the SPARC interface. The Appendix provides a detailed description of themore » physics and engineering models used in ASM. ASM Version 1.0 is joint project of G. H. Gillespie Associates, Inc. and the Accelerator Technology (AT) Division of the Los Alamos National Laboratory. Neither the ASM Version 1.0 software nor this ASM Documentation may be reproduced without the expressed written consent of both the Los Alamos National Laboratory and G. H. Gillespie Associates, Inc.« less

  1. Computer Program and User Documentation Medical Data Update System

    NASA Technical Reports Server (NTRS)

    Anderson, J.

    1971-01-01

    The update system for the NASA medical data minicomputer storage and retrieval system is described. The discussion includes general and technical specifications, a subroutine list, and programming instructions.

  2. User's manual for the NASA Lewis ice accretion/heat transfer prediction code with electrothermal deicer input

    NASA Technical Reports Server (NTRS)

    Masiulaniec, Konstanty C.; Wright, William B.

    1994-01-01

    A version of LEWICE has been developed that incorporates a recently developed electrothermal deicer code, developed at the University of Toledo by William B. Wright. This was accomplished, in essence, by replacing a subroutine in LEWICE, called EBAL, which balanced the energies at the ice surface, with a subroutine called UTICE. UTICE performs this same energy balance, as well as handles all the time-timperature transients below the ice surface, for all of the layers of a composite blade as well as the ice layer itself. This new addition is set up in such a fashion that a user may specify any number of heaters, any heater chordwise length, and any heater gap desired. The heaters may be fired in unison, or they may be cycled with periods independent of each other. The heater intensity may also be varied. In addition, the user may specify any number of layers and thicknesses depthwise into the blade. Thus, the new addition has maximum flexibility in modeling virtually any electrothermal deicer installed into any airfoil. It should be noted that the model simulates both shedding and runback. With the runback capability, it can simulate the anti-icing mode of heater performance, as well as detect icing downstream of the heaters due to runback in unprotected portions of the airfoil. This version of LEWICE can be run in three modes. In mode 1, no conduction heat transfer is modeled (which would be equivalent to the original version of LEWICE). In mode 2, all heat transfer is considered due to conduction but no heaters are firing. In mode 3, conduction heat transfer where the heaters are engaged is modeled, with subsequent ice shedding. When run in the first mode, there is virtually identical agreement with the original version of LEWICE in the prediction of accreted ice shapes. The code may be run in the second mode to determine the effects of conduction on the ice accretion process.

  3. Research on stress distribution regularity of cement sheaths of radial well based on ABAQUS

    NASA Astrophysics Data System (ADS)

    Shi, Jihui; Cheng, Yuanfang; Li, Xiaolong; Xiao, Wen; Li, Menglai

    2017-12-01

    To ensure desirable outcome of hydraulic fracturing based on ultra-short radius radial systems, it is required to investigate the stress distribution regularity and stability of the cement sheath. On the basis of the theoretical model of the cement sheath stress distribution, a reservoir mechanical model was built using the finite element software, ABAQUS, according to the physical property of a certain oil reservoir of the Shengli oilfield. The stress distribution of the casing-cement-sheath-formation system under the practical condition was simulated, based on which analyses were conducted from multiple points of view. Results show that the stress on the internal interface of the cement sheath exceeds that on the external interface, and fluctuates with higher amplitudes, which means that the internal interface is the most failure-prone. The unevenness of the cement sheath stress distribution grows with the increasing horizontal principal stress ratio, and so does the variation magnitude. This indicates that higher horizontal principal stress ratios are unfavourable for the structural stability of the cement sheath. Both the wellbore quantity of the URRS and the physical property of the material can affect the cement sheath distribution. It is suggested to optimize the quantity of the radial wellbore and use cement with a lower elastic modulus and higher Poisson’s ratio. At last, the impact level of the above factor was analysed, with the help of the grey correlation analysis.

  4. Mars Global Reference Atmospheric Model 2000 Version (Mars-GRAM 2000): Users Guide

    NASA Technical Reports Server (NTRS)

    Justus, C. G.; James, B. F.

    2000-01-01

    This report presents Mars Global Reference Atmospheric Model 2000 Version (Mars-GRAM 2000) and its new features. All parameterizations for temperature, pressure, density, and winds versus height, latitude, longitude, time of day, and L(sub s) have been replaced by input data tables from NASA Ames Mars General Circulation Model (MGCM) for the surface through 80-km altitude and the University of Arizona Mars Thermospheric General Circulation Model (MTGCM) for 80 to 170 km. A modified Stewart thermospheric model is still used for higher altitudes and for dependence on solar activity. "Climate factors" to tune for agreement with GCM data are no longer needed. Adjustment of exospheric temperature is still an option. Consistent with observations from Mars Global Surveyor, a new longitude-dependent wave model is included with user input to specify waves having 1 to 3 wavelengths around the planet. A simplified perturbation model has been substituted for the earlier one. An input switch allows users to select either East or West longitude positive. This memorandum includes instructions on obtaining Mars-GRAM source code and data files and for running the program. It also provides sample input and output and an example for incorporating Mars-GRAM as an atmospheric subroutine in a trajectory code.

  5. Finite Element Analysis of Adaptive-Stiffening and Shape-Control SMA Hybrid Composites

    NASA Technical Reports Server (NTRS)

    Gao, Xiujie; Burton, Deborah; Turner, Travis L.; Brinson, Catherine

    2005-01-01

    Shape memory alloy hybrid composites with adaptive-stiffening or morphing functions are simulated using finite element analysis. The composite structure is a laminated fiber-polymer composite beam with embedded SMA ribbons at various positions with respect to the neutral axis of the beam. Adaptive stiffening or morphing is activated via selective resistance heating of the SMA ribbons or uniform thermal loads on the beam. The thermomechanical behavior of these composites was simulated in ABAQUS using user-defined SMA elements. The examples demonstrate the usefulness of the methods for the design and simulation of SMA hybrid composites. Keywords: shape memory alloys, Nitinol, ABAQUS, finite element analysis, post-buckling control, shape control, deflection control, adaptive stiffening, morphing, constitutive modeling, user element

  6. User's guide for GSMP, a General System Modeling Program. [In PL/I

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cook, J. M.

    1979-10-01

    GSMP is designed for use by systems analysis teams. Given compiled subroutines that model the behavior of components plus instructions as to how they are to be interconnected, this program links them together to model a complete system. GSMP offers a fast response to management requests for reconfigurations of old systems and even initial configurations of new systems. Standard system-analytic services are provided: parameter sweeps, graphics, free-form input and formatted output, file storage and recovery, user-tested error diagnostics, component model and integration checkout and debugging facilities, sensitivity analysis, and a multimethod optimizer with nonlinear constraint handling capability. Steady-state or cyclicmore » time-dependence is simulated directly, initial-value problems only indirectly. The code is written in PL/I, but interfaces well with FORTRAN component models. Over the last five years GSMP has been used to model theta-pinch, tokamak, and heavy-ion fusion power plants, open- and closed-cycle magneto-hydrodynamic power plants, and total community energy systems.« less

  7. Final Shape of Precision Molded Optics: Part 1 - Computational Approach, Material Definitions and the Effect of Lens Shape

    DTIC Science & Technology

    2012-05-15

    subroutine by adding time-dependence to the thermal expansion coefficient. The user subroutine was written in Intel Visual Fortran that is compatible...temperature history dependent expansion and contraction, and the molds were modeled as elastic taking into account both mechanical and thermal strain. In...behavior was approximated by assuming the thermal coefficient of expansion to be a fourth order polynomial function of temperature. The authors

  8. A modular finite-element model (MODFE) for areal and axisymmetric ground-water-flow problems, Part 3: Design philosophy and programming details

    USGS Publications Warehouse

    Torak, L.J.

    1993-01-01

    A MODular Finite-Element, digital-computer program (MODFE) was developed to simulate steady or unsteady-state, two-dimensional or axisymmetric ground-water-flow. The modular structure of MODFE places the computationally independent tasks that are performed routinely by digital-computer programs simulating ground-water flow into separate subroutines, which are executed from the main program by control statements. Each subroutine consists of complete sets of computations, or modules, which are identified by comment statements, and can be modified by the user without affecting unrelated computations elsewhere in the program. Simulation capabilities can be added or modified by either adding or modifying subroutines that perform specific computational tasks, and the modular-program structure allows the user to create versions of MODFE that contain only the simulation capabilities that pertain to the ground-water problem of interest. MODFE is written in a Fortran programming language that makes it virtually device independent and compatible with desk-top personal computers and large mainframes. MODFE uses computer storage and execution time efficiently by taking advantage of symmetry and sparseness within the coefficient matrices of the finite-element equations. Parts of the matrix coefficients are computed and stored as single-subscripted variables, which are assembled into a complete coefficient just prior to solution. Computer storage is reused during simulation to decrease storage requirements. Descriptions of subroutines that execute the computational steps of the modular-program structure are given in tables that cross reference the subroutines with particular versions of MODFE. Programming details of linear and nonlinear hydrologic terms are provided. Structure diagrams for the main programs show the order in which subroutines are executed for each version and illustrate some of the linear and nonlinear versions of MODFE that are possible. Computational aspects of

  9. Slave finite element for non-linear analysis of engine structures. Volume 2: Programmer's manual and user's manual

    NASA Technical Reports Server (NTRS)

    Witkop, D. L.; Dale, B. J.; Gellin, S.

    1991-01-01

    The programming aspects of SFENES are described in the User's Manual. The information presented is provided for the installation programmer. It is sufficient to fully describe the general program logic and required peripheral storage. All element generated data is stored externally to reduce required memory allocation. A separate section is devoted to the description of these files thereby permitting the optimization of Input/Output (I/O) time through efficient buffer descriptions. Individual subroutine descriptions are presented along with the complete Fortran source listings. A short description of the major control, computation, and I/O phases is included to aid in obtaining an overall familiarity with the program's components. Finally, a discussion of the suggested overlay structure which allows the program to execute with a reasonable amount of memory allocation is presented.

  10. Representing Matrix Cracks Through Decomposition of the Deformation Gradient Tensor in Continuum Damage Mechanics Methods

    NASA Technical Reports Server (NTRS)

    Leone, Frank A., Jr.

    2015-01-01

    A method is presented to represent the large-deformation kinematics of intraply matrix cracks and delaminations in continuum damage mechanics (CDM) constitutive material models. The method involves the additive decomposition of the deformation gradient tensor into 'crack' and 'bulk material' components. The response of the intact bulk material is represented by a reduced deformation gradient tensor, and the opening of an embedded cohesive interface is represented by a normalized cohesive displacement-jump vector. The rotation of the embedded interface is tracked as the material deforms and as the crack opens. The distribution of the total local deformation between the bulk material and the cohesive interface components is determined by minimizing the difference between the cohesive stress and the bulk material stress projected onto the cohesive interface. The improvements to the accuracy of CDM models that incorporate the presented method over existing approaches are demonstrated for a single element subjected to simple shear deformation and for a finite element model of a unidirectional open-hole tension specimen. The material model is implemented as a VUMAT user subroutine for the Abaqus/Explicit finite element software. The presented deformation gradient decomposition method reduces the artificial load transfer across matrix cracks subjected to large shearing deformations, and avoids the spurious secondary failure modes that often occur in analyses based on conventional progressive damage models.

  11. A viscoplastic study of crack-tip deformation and crack growth in a nickel-based superalloy at elevated temperature

    NASA Astrophysics Data System (ADS)

    Zhao, L. G.; Tong, J.

    Viscoplastic crack-tip deformation behaviour in a nickel-based superalloy at elevated temperature has been studied for both stationary and growing cracks in a compact tension (CT) specimen using the finite element method. The material behaviour was described by a unified viscoplastic constitutive model with non-linear kinematic and isotropic hardening rules, and implemented in the finite element software ABAQUS via a user-defined material subroutine (UMAT). Finite element analyses for stationary cracks showed distinctive strain ratchetting behaviour near the crack tip at selected load ratios, leading to progressive accumulation of tensile strain normal to the crack-growth plane. Results also showed that low frequencies and superimposed hold periods at peak loads significantly enhanced strain accumulation at crack tip. Finite element simulation of crack growth was carried out under a constant Δ K-controlled loading condition, again ratchetting was observed ahead of the crack tip, similar to that for stationary cracks. A crack-growth criterion based on strain accumulation is proposed where a crack is assumed to grow when the accumulated strain ahead of the crack tip reaches a critical value over a characteristic distance. The criterion has been utilized in the prediction of crack-growth rates in a CT specimen at selected loading ranges, frequencies and dwell periods, and the predictions were compared with the experimental results.

  12. Predicting the mixed-mode I/II spatial damage propagation along 3D-printed soft interfacial layer via a hyperelastic softening model

    NASA Astrophysics Data System (ADS)

    Liu, Lei; Li, Yaning

    2018-07-01

    A methodology was developed to use a hyperelastic softening model to predict the constitutive behavior and the spatial damage propagation of nonlinear materials with damage-induced softening under mixed-mode loading. A user subroutine (ABAQUS/VUMAT) was developed for numerical implementation of the model. 3D-printed wavy soft rubbery interfacial layer was used as a material system to verify and validate the methodology. The Arruda - Boyce hyperelastic model is incorporated with the softening model to capture the nonlinear pre-and post- damage behavior of the interfacial layer under mixed Mode I/II loads. To characterize model parameters of the 3D-printed rubbery interfacial layer, a series of scarf-joint specimens were designed, which enabled systematic variation of stress triaxiality via a single geometric parameter, the slant angle. It was found that the important model parameter m is exponentially related to the stress triaxiality. Compact tension specimens of the sinusoidal wavy interfacial layer with different waviness were designed and fabricated via multi-material 3D printing. Finite element (FE) simulations were conducted to predict the spatial damage propagation of the material within the wavy interfacial layer. Compact tension experiments were performed to verify the model prediction. The results show that the model developed is able to accurately predict the damage propagation of the 3D-printed rubbery interfacial layer under complicated stress-state without pre-defined failure criteria.

  13. Thermo-hydroforming of a fiber-reinforced thermoplastic composites considering fiber orientations

    NASA Astrophysics Data System (ADS)

    Ahn, Hyunchul; Kuuttila, Nicholas Eric; Pourboghrat, Farhang

    2018-05-01

    The Thermoplastic woven composites were formed using a composite thermal hydroforming process, utilizing heated and pressurized fluid, similar to sheet metal forming. This study focuses on the modification of 300-ton pressure formation and predicts its behavior. Spectra Shield SR-3136 is used in this study and material properties are measured by experiments. The behavior of fiber-reinforced thermoplastic polymer composites (FRTP) was modeled using the Preferred Fiber Orientation (PFO) model and validated by comparing numerical analysis with experimental results. The thermo-hydroforming process has shown good results in the ability to form deep drawn parts with reduced wrinkles. Numerical analysis was performed using the PFO model and implemented as commercial finite element software ABAQUS / Explicit. The user subroutine (VUMAT) was used for the material properties of the thermoplastic composite layer. This model is suitable for working with multiple layers of composite laminates. Model parameters have been updated to work with cohesive zone model to calculate the interfacial properties between each composite layer. The results of the numerical modeling showed a good correlation with the molding experiment on the forming shape. Numerical results were also compared with experimental results on punch force-displacement curves for deformed geometry and forming processes of the composite layer. Overall, the shape of the deformed FRTP, including the distribution of wrinkles, was accurately predicted as shown in this study.

  14. A unified dislocation density-dependent physical-based constitutive model for cold metal forming

    NASA Astrophysics Data System (ADS)

    Schacht, K.; Motaman, A. H.; Prahl, U.; Bleck, W.

    2017-10-01

    Dislocation-density-dependent physical-based constitutive models of metal plasticity while are computationally efficient and history-dependent, can accurately account for varying process parameters such as strain, strain rate and temperature; different loading modes such as continuous deformation, creep and relaxation; microscopic metallurgical processes; and varying chemical composition within an alloy family. Since these models are founded on essential phenomena dominating the deformation, they have a larger range of usability and validity. Also, they are suitable for manufacturing chain simulations since they can efficiently compute the cumulative effect of the various manufacturing processes by following the material state through the entire manufacturing chain and also interpass periods and give a realistic prediction of the material behavior and final product properties. In the physical-based constitutive model of cold metal plasticity introduced in this study, physical processes influencing cold and warm plastic deformation in polycrystalline metals are described using physical/metallurgical internal variables such as dislocation density and effective grain size. The evolution of these internal variables are calculated using adequate equations that describe the physical processes dominating the material behavior during cold plastic deformation. For validation, the model is numerically implemented in general implicit isotropic elasto-viscoplasticity algorithm as a user-defined material subroutine (UMAT) in ABAQUS/Standard and used for finite element simulation of upsetting tests and a complete cold forging cycle of case hardenable MnCr steel family.

  15. Modelling approach for anisotropic inter-ply slippage in finite element forming simulation of thermoplastic UD-tapes

    NASA Astrophysics Data System (ADS)

    Dörr, Dominik; Faisst, Markus; Joppich, Tobias; Poppe, Christian; Henning, Frank; Kärger, Luise

    2018-05-01

    Finite Element (FE) forming simulation offers the possibility of a detailed analysis of thermoforming processes by means of constitutive modelling of intra- and inter-ply deformation mechanisms, which makes manufacturing defects predictable. Inter-ply slippage is a deformation mechanism, which influences the forming behaviour and which is usually assumed to be isotropic in FE forming simulation so far. Thus, the relative (fibre) orientation between the slipping plies is neglected for modelling of frictional behaviour. Characterization results, however, reveal a dependency of frictional behaviour on the relative orientation of the slipping plies. In this work, an anisotropic model for inter-ply slippage is presented, which is based on an FE forming simulation approach implemented within several user subroutines of the commercially available FE solver Abaqus. This approach accounts for the relative orientation between the slipping plies for modelling frictional behaviour. For this purpose, relative orientation of the slipping plies is consecutively evaluated, since it changes during forming due to inter-ply slipping and intra-ply shearing. The presented approach is parametrized based on characterization results with and without relative orientation for a thermoplastic UD-tape (PA6-CF) and applied to forming simulation of a generic geometry. Forming simulation results reveal an influence of the consideration of relative fibre orientation on the simulation results. This influence, however, is small for the considered geometry.

  16. A 3/D finite element approach for metal matrix composites based on micromechanical models

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Svobodnik, A.J.; Boehm, H.J.; Rammerstorfer, F.G.

    Based on analytical considerations by Dvorak and Bahel-El-Din, a 3/D finite element material law has been developed for the elastic-plastic analysis of unidirectional fiber-reinforced metal matrix composites. The material law described in this paper has been implemented in the finite element code ABAQUS via the user subroutine UMAT. A constitutive law is described under the assumption that the fibers are linear-elastic and the matrix is of a von Mises-type with a Prager-Ziegler kinematic hardening rule. The uniaxial effective stress-strain relationship of the matrix in the plastic range is approximated by a Ramberg-Osgood law, a linear hardening rule or a nonhardeningmore » rule. Initial yield surface of the matrix material and for the fiber reinforced composite are compared to show the effect of reinforcement. Implementation of this material law in a finite element program is shown. Furthermore, the efficiency of substepping schemes and stress corrections for the numerical integration of the elastic-plastic stress-strain relations for anisotropic materials are investigated. The results of uniaxial monotonic tests of a boron/aluminum composite are compared to some finite element analyses based on micromechanical considerations. Furthermore a complete 3/D analysis of a tensile test specimen made of a silicon-carbide/aluminum MMC and the analysis of an MMC inlet inserted in a homogenous material are shown. 12 refs.« less

  17. A coupled mechanical-chemical model for reflecting the influence of stress on oxidation reactions in thermal barrier coating

    NASA Astrophysics Data System (ADS)

    Chen, Lin; Yueming, Li

    2018-06-01

    In this paper, a coupled mechanical-chemical model is established based on the thermodynamic framework, in which the contribution of chemical expansion to free energy is introduced. The stress-dependent chemical potential equilibrium at the gas-solid interface and the stress gradient-dependent diffusion equation as well as a so-called generalized force which is conjugate to the oxidation rate are derived from the proposed model, which could reflect the influence of stresses on the oxidation reaction. Based on the proposed coupled mechanical-chemical model, a user element subroutine is developed in ABAQUS. The numerical simulation of the high temperature oxidation in the thermal barrier coating is carried out to verify the accuracy of the proposed model, and then the influence of stresses on the oxidation reaction is investigated. In thermally grown oxide, the considerable stresses would be induced by permanent volumetric swelling during the oxidation. The stresses play an important role in the chemical potential equilibrium at the gas-solid interface and strongly affect the oxidation reaction. The gradient of the stresses, however, only occurs in the extremely thin oxidation front layer, which plays a very limited role in the oxidation reaction. The generalized force could be divided into the stress-dependent and the stress-independent parts. Comparing with the stress-independent part, the stress-dependent part is smaller, which has little influence on oxidation reaction.

  18. Dislocation based controlling of kinematic hardening contribution to simulate primary and secondary stages of uniaxial ratcheting

    NASA Astrophysics Data System (ADS)

    Bhattacharjee, S.; Dhar, S.; Acharyya, S. K.

    2017-07-01

    The primary and secondary stages of the uniaxial ratcheting curve for the C-Mn steel SA333 have been investigated. Stress controlled uniaxial ratcheting experiments were conducted with different mean stresses and stress amplitudes to obtain curves showing the evolution of ratcheting strain with number of cycles. In stage-I of the ratcheting curve, a large accumulation of ratcheting strain occurs, but at a decreasing rate. In contrast, in stage-II a smaller accumulation of ratcheting strain is found and the ratcheting rate becomes almost constant. Transmission electron microscope observations reveal that no specific dislocation structures are developed during the early stages of ratcheting. Rather, compared with the case of low cycle fatigue, it is observed that sub-cell formation is delayed in the case of ratcheting. The increase in dislocation density as a result of the ratcheting strain is obtained using the Orowan equation. The ratcheting strain is obtained from the shift of the plastic strain memory surface. The dislocation rearrangement is incorporated in a functional form of dislocation density, which is used to calibrate the parameters of a kinematic hardening law. The observations are formulated in a material model, plugged into the ABAQUS finite element (FE) platform as a user material subroutine. Finally the FE-simulated ratcheting curves are compared with the experimental curves.

  19. Constitutive modeling of polycarbonate over a wide range of strain rates and temperatures

    NASA Astrophysics Data System (ADS)

    Wang, Haitao; Zhou, Huamin; Huang, Zhigao; Zhang, Yun; Zhao, Xiaoxuan

    2017-02-01

    The mechanical behavior of polycarbonate was experimentally investigated over a wide range of strain rates (10^{-4} to 5× 103 s^{-1}) and temperatures (293 to 353 K). Compression tests under these conditions were performed using a SHIMADZU universal testing machine and a split Hopkinson pressure bar. Falling weight impact testing was carried out on an Instron Dynatup 9200 drop tower system. The rate- and temperature-dependent deformation behavior of polycarbonate was discussed in detail. Dynamic mechanical analysis (DMA) tests were utilized to observe the glass (α ) transition and the secondary (β ) transition of polycarbonate. The DMA results indicate that the α and β transitions have a dramatic influence on the mechanical behavior of polycarbonate. The decompose/shift/reconstruct (DSR) method was utilized to decompose the storage modulus into the α and β components and extrapolate the entire modulus, the α-component modulus and the β-component modulus. Based on three previous models, namely, Mulliken-Boyce, G'Sell-Jonas and DSGZ, an adiabatic model is proposed to predict the mechanical behavior of polycarbonate. The model considers the contributions of both the α and β transitions to the mechanical behavior, and it has been implemented in ABAQUS/Explicit through a user material subroutine VUMAT. The model predictions are proven to essentially coincide with the experimental results during compression testing and falling weight impact testing.

  20. UMAT Implementation of Coupled, Multilevel, Structural Deformation and Damage Analysis of General Hereditary Materials

    NASA Technical Reports Server (NTRS)

    Arnold, S. M.; Saleeb, A. F.; Wilt, T. E.; Trowbridge, D.

    2000-01-01

    be incorporated directly into a structural finite element code like ABAQUS for cost-effective, micromechanics based, large-scale component design and analysis. Our primary objective here is to report on these recent works conducted over the past decade, in the context of their incorporation into ABAQUS through the various user subroutines. Representative results will be shown to demonstrate the features of the developed schemes.

  1. Failure prediction during backward flow forming of Ti6Al4V alloy

    NASA Astrophysics Data System (ADS)

    Singh, Abhishek Kumar; Narasimhan, K.; Singh, Ramesh

    2018-05-01

    The Flow forming process is a tube spinning process where the thickness of a tube is reduced with the help of spinning roller/s by keeping the internal diameter unchanged. A 3-D Finite element model for the flow-formability test has been developed by using Abaqus/explicit software. A coupled damage criterion based on continuum damage mechanics (CDM) has been studied in this research. The damage model is introduced by using FORTRAN based VUMAT subroutine which is developed through a stress integration algorithm. Further, the effect of reduction angle, friction coefficient, and coolant heat transfer coefficient on fracture has been studied. The results show that the formability improves with increase in reduction angle. Both, equivalent plastic strain and damage variable increases from inner to outer surface of flow formed tube.

  2. Function algorithms for MPP scientific subroutines, volume 1

    NASA Technical Reports Server (NTRS)

    Gouch, J. G.

    1984-01-01

    Design documentation and user documentation for function algorithms for the Massively Parallel Processor (MPP) are presented. The contract specifies development of MPP assembler instructions to perform the following functions: natural logarithm; exponential (e to the x power); square root; sine; cosine; and arctangent. To fulfill the requirements of the contract, parallel array and solar implementations for these functions were developed on the PDP11/34 Program Development and Management Unit (PDMU) that is resident at the MPP testbed installation located at the NASA Goddard facility.

  3. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hobbs, Michael L.

    We previously developed a PETN thermal decomposition model that accurately predicts thermal ignition and detonator failure [1]. This model was originally developed for CALORE [2] and required several complex user subroutines. Recently, a simplified version of the PETN decomposition model was implemented into ARIA [3] using a general chemistry framework without need for user subroutines. Detonator failure was also predicted with this new model using ENCORE. The model was simplified by 1) basing the model on moles rather than mass, 2) simplifying the thermal conductivity model, and 3) implementing ARIA’s new phase change model. This memo briefly describes the model,more » implementation, and validation.« less

  4. A Formal Approach to Domain-Oriented Software Design Environments

    NASA Technical Reports Server (NTRS)

    Lowry, Michael; Philpot, Andrew; Pressburger, Thomas; Underwood, Ian; Lum, Henry, Jr. (Technical Monitor)

    1994-01-01

    This paper describes a formal approach to domain-oriented software design environments, based on declarative domain theories, formal specifications, and deductive program synthesis. A declarative domain theory defines the semantics of a domain-oriented specification language and its relationship to implementation-level subroutines. Formal specification development and reuse is made accessible to end-users through an intuitive graphical interface that guides them in creating diagrams denoting formal specifications. The diagrams also serve to document the specifications. Deductive program synthesis ensures that end-user specifications are correctly implemented. AMPHION has been applied to the domain of solar system kinematics through the development of a declarative domain theory, which includes an axiomatization of JPL's SPICELIB subroutine library. Testing over six months with planetary scientists indicates that AMPHION's interactive specification acquisition paradigm enables users to develop, modify, and reuse specifications at least an order of magnitude more rapidly than manual program development. Furthermore, AMPHION synthesizes one to two page programs consisting of calls to SPICELIB subroutines from these specifications in just a few minutes. Test results obtained by metering AMPHION's deductive program synthesis component are examined. AMPHION has been installed at JPL and is currently undergoing further refinement in preparation for distribution to hundreds of SPICELIB users worldwide. Current work to support end-user customization of AMPHION's specification acquisition subsystem is briefly discussed, as well as future work to enable domain-expert creation of new AMPHION applications through development of suitable domain theories.

  5. Computer Program for Calculation of Complex Chemical Equilibrium Compositions and Applications II. Users Manual and Program Description. 2; Users Manual and Program Description

    NASA Technical Reports Server (NTRS)

    McBride, Bonnie J.; Gordon, Sanford

    1996-01-01

    This users manual is the second part of a two-part report describing the NASA Lewis CEA (Chemical Equilibrium with Applications) program. The program obtains chemical equilibrium compositions of complex mixtures with applications to several types of problems. The topics presented in this manual are: (1) details for preparing input data sets; (2) a description of output tables for various types of problems; (3) the overall modular organization of the program with information on how to make modifications; (4) a description of the function of each subroutine; (5) error messages and their significance; and (6) a number of examples that illustrate various types of problems handled by CEA and that cover many of the options available in both input and output. Seven appendixes give information on the thermodynamic and thermal transport data used in CEA; some information on common variables used in or generated by the equilibrium module; and output tables for 14 example problems. The CEA program was written in ANSI standard FORTRAN 77. CEA should work on any system with sufficient storage. There are about 6300 lines in the source code, which uses about 225 kilobytes of memory. The compiled program takes about 975 kilobytes.

  6. Guidelines and Parameter Selection for the Simulation of Progressive Delamination

    NASA Technical Reports Server (NTRS)

    Song, Kyongchan; Davila, Carlos G.; Rose, Cheryl A.

    2008-01-01

    Turon s methodology for determining optimal analysis parameters for the simulation of progressive delamination is reviewed. Recommended procedures for determining analysis parameters for efficient delamination growth predictions using the Abaqus/Standard cohesive element and relatively coarse meshes are provided for single and mixed-mode loading. The Abaqus cohesive element, COH3D8, and a user-defined cohesive element are used to develop finite element models of the double cantilever beam specimen, the end-notched flexure specimen, and the mixed-mode bending specimen to simulate progressive delamination growth in Mode I, Mode II, and mixed-mode fracture, respectively. The predicted responses are compared with their analytical solutions. The results show that for single-mode fracture, the predicted responses obtained with the Abaqus cohesive element correlate well with the analytical solutions. For mixed-mode fracture, it was found that the response predicted using COH3D8 elements depends on the damage evolution criterion that is used. The energy-based criterion overpredicts the peak loads and load-deflection response. The results predicted using a tabulated form of the BK criterion correlate well with the analytical solution and with the results predicted with the user-written element.

  7. Rotor Wake/Stator Interaction Noise Prediction Code Technical Documentation and User's Manual

    NASA Technical Reports Server (NTRS)

    Topol, David A.; Mathews, Douglas C.

    2010-01-01

    This report documents the improvements and enhancements made by Pratt & Whitney to two NASA programs which together will calculate noise from a rotor wake/stator interaction. The code is a combination of subroutines from two NASA programs with many new features added by Pratt & Whitney. To do a calculation V072 first uses a semi-empirical wake prediction to calculate the rotor wake characteristics at the stator leading edge. Results from the wake model are then automatically input into a rotor wake/stator interaction analytical noise prediction routine which calculates inlet aft sound power levels for the blade-passage-frequency tones and their harmonics, along with the complex radial mode amplitudes. The code allows for a noise calculation to be performed for a compressor rotor wake/stator interaction, a fan wake/FEGV interaction, or a fan wake/core stator interaction. This report is split into two parts, the first part discusses the technical documentation of the program as improved by Pratt & Whitney. The second part is a user's manual which describes how input files are created and how the code is run.

  8. Transpiration and film cooling boundary layer computer program. Volume 2: Computer program and user's manual

    NASA Technical Reports Server (NTRS)

    Gloss, R. J.

    1971-01-01

    A finite difference turbulent boundary layer computer program which allows for mass transfer wall cooling and equilibrium chemistry effects is presented. The program is capable of calculating laminar or turbulent boundary layer solutions for an arbitrary ideal gas or an equilibrium hydrogen oxygen system. Either two dimensional or axisymmetric geometric configurations may be considered. The equations are solved, in nondimension-alized physical coordinates, using the implicit Crank-Nicolson technique. The finite difference forms of the conservation of mass, momentum, total enthalpy and elements equations are linearized and uncoupled, thereby generating easily solvable tridiagonal sets of algebraic equations. A detailed description of the computer program, as well as a program user's manual is provided. Detailed descriptions of all boundary layer subroutines are included, as well as a section defining all program symbols of principal importance. Instructions are then given for preparing card input to the program and for interpreting the printed output. Finally, two sample cases are included to illustrate the use of the program.

  9. Multiphysics of bone remodeling: A 2D mesoscale activation simulation.

    PubMed

    Spingarn, C; Wagner, D; Rémond, Y; George, D

    2017-01-01

    In this work, we present an evolutive trabecular model for bone remodeling based on a boundary detection algorithm accounting for both biology and applied mechanical forces, known to be an important factor in bone evolution. A finite element (FE) numerical model using the Abaqus/Standard® software was used with a UMAT subroutine to solve the governing coupled mechanical-biological non-linear differential equations of the bone evolution model. The simulations present cell activation on a simplified trabeculae configuration organization with trabecular thickness of 200µm. For this activation process, the results confirm that the trabeculae are mainly oriented in the active direction of the principal mechanical stresses and according to the principal applied mechanical load directions. The trabeculae surface activation is clearly identified and can provide understanding of the different bone cell activations in more complex geometries and load conditions.

  10. Sandia National Laboratories environmental fluid dynamics code. Marine Hydrokinetic Module User's Manual

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    James, Scott Carlton; Roberts, Jesse D.

    2014-03-01

    This document describes the marine hydrokinetic (MHK) input file and subroutines for the Sandia National Laboratories Environmental Fluid Dynamics Code (SNL-EFDC), which is a combined hydrodynamic, sediment transport, and water quality model based on the Environmental Fluid Dynamics Code (EFDC) developed by John Hamrick [1], formerly sponsored by the U.S. Environmental Protection Agency, and now maintained by Tetra Tech, Inc. SNL-EFDC has been previously enhanced with the incorporation of the SEDZLJ sediment dynamics model developed by Ziegler, Lick, and Jones [2-4]. SNL-EFDC has also been upgraded to more accurately simulate algae growth with specific application to optimizing biomass in anmore » open-channel raceway for biofuels production [5]. A detailed description of the input file containing data describing the MHK device/array is provided, along with a description of the MHK FORTRAN routine. Both a theoretical description of the MHK dynamics as incorporated into SNL-EFDC and an explanation of the source code are provided. This user manual is meant to be used in conjunction with the original EFDC [6] and sediment dynamics SNL-EFDC manuals [7]. Through this document, the authors provide information for users who wish to model the effects of an MHK device (or array of devices) on a flow system with EFDC and who also seek a clear understanding of the source code, which is available from staff in the Water Power Technologies Department at Sandia National Laboratories, Albuquerque, New Mexico.« less

  11. User's manual for rocket combustor interactive design (ROCCID) and analysis computer program. Volume 2: Appendixes A-K

    NASA Technical Reports Server (NTRS)

    Muss, J. A.; Nguyen, T. V.; Johnson, C. W.

    1991-01-01

    The appendices A-K to the user's manual for the rocket combustor interactive design (ROCCID) computer program are presented. This includes installation instructions, flow charts, subroutine model documentation, and sample output files. The ROCCID program, written in Fortran 77, provides a standardized methodology using state of the art codes and procedures for the analysis of a liquid rocket engine combustor's steady state combustion performance and combustion stability. The ROCCID is currently capable of analyzing mixed element injector patterns containing impinging like doublet or unlike triplet, showerhead, shear coaxial and swirl coaxial elements as long as only one element type exists in each injector core, baffle, or barrier zone. Real propellant properties of oxygen, hydrogen, methane, propane, and RP-1 are included in ROCCID. The properties of other propellants can be easily added. The analysis models in ROCCID can account for the influences of acoustic cavities, helmholtz resonators, and radial thrust chamber baffles on combustion stability. ROCCID also contains the logic to interactively create a combustor design which meets input performance and stability goals. A preliminary design results from the application of historical correlations to the input design requirements. The steady state performance and combustion stability of this design is evaluated using the analysis models, and ROCCID guides the user as to the design changes required to satisfy the user's performance and stability goals, including the design of stability aids. Output from ROCCID includes a formatted input file for the standardized JANNAF engine performance prediction procedure.

  12. [Numeric simulation of functional remodeling of the anterior alveolar bone].

    PubMed

    Wang, Wei-feng; Xin, Hai-tao; Zang, Shun-lai; Ding, Jie

    2012-04-01

    To study the remodeling of the anterior alveolar bone with parodontium under physiology loading using finite element method (FEM) and theory of bone remodeling. A FEM model of the maxillary central incisor with parodontium was established, and the change of bone density during the remodeling of alveolar bone was investigated under physiology loading (60 - 150 N) based on the theory of bone remodeling about strain energy density (SED). The finite element analysis software Abaqus user material subroutine (UMAT) were used. With the increase of physiology loading, the pressure stress on the buccal cervical margin increased gradually while the density was decreased gradually. The cortical bone was lower than its initial density 1.74 g/cm(3), which was 1.74 - 1.63 g/cm(3). The density of cancellous bone was 0.90 - 0.77 g/cm(3), which was lower than its intial density 0.90 g/cm(3). The lingual cervical margin was under tensile stress which also increased with loading, the density had no significant change. When the achieve to 120 N, the density of cortical bone was 1.74 - 1.73 g/cm(3). No significant change was found in the cancellous bone. The simulation of the perodontium remodeling is achieved and proved to be effective by the relevant research based on the method of the study. And the result will be helpful to form the basis of analysis bone remodeling process and predict the results in the clinical work.

  13. Preliminary Development of a Unified Viscoplastic Constitutive Model for Alloy 617 with Special Reference to Long Term Creep Behavior

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sham, Sam; Walker, Kevin P.

    The expected service life of the Next Generation Nuclear Plant is 60 years. Structural analyses of the Intermediate Heat Exchanger (IHX) will require the development of unified viscoplastic constitutive models that address the material behavior of Alloy 617, a construction material of choice, over a wide range of strain rates. Many unified constitutive models employ a yield stress state variable which is used to account for cyclic hardening and softening of the material. For low stress values below the yield stress state variable these constitutive models predict that no inelastic deformation takes place which is contrary to experimental results. Themore » ability to model creep deformation at low stresses for the IHX application is very important as the IHX operational stresses are restricted to very small values due to the low creep strengths at elevated temperatures and long design lifetime. This paper presents some preliminary work in modeling the unified viscoplastic constitutive behavior of Alloy 617 which accounts for the long term, low stress, creep behavior and the hysteretic behavior of the material at elevated temperatures. The preliminary model is presented in one-dimensional form for ease of understanding, but the intent of the present work is to produce a three-dimensional model suitable for inclusion in the user subroutines UMAT and USERPL of the ABAQUS and ANSYS nonlinear finite element codes. Further experiments and constitutive modeling efforts are planned to model the material behavior of Alloy 617 in more detail.« less

  14. A visco-hyperelastic constitutive model and its application in bovine tongue tissue.

    PubMed

    Yousefi, Ali-Akbar Karkhaneh; Nazari, Mohammad Ali; Perrier, Pascal; Panahi, Masoud Shariat; Payan, Yohan

    2018-04-11

    Material properties of the human tongue tissue have a significant role in understanding its function in speech, respiration, suckling, and swallowing. Tongue as a combination of various muscles is surrounded by the mucous membrane and is a complicated architecture to study. As a first step before the quantitative mechanical characterization of human tongue tissues, the passive biomechanical properties in the superior longitudinal muscle (SLM) and the mucous tissues of a bovine tongue have been measured. Since the rate of loading has a sizeable contribution to the resultant stress of soft tissues, the rate dependent behavior of tongue tissues has been investigated via uniaxial tension tests (UTTs). A method to determine the mechanical properties of transversely isotropic tissues using UTTs and inverse finite element (FE) method has been proposed. Assuming the strain energy as a general nonlinear relationship with respect to the stretch and the rate of stretch, two visco-hyperelastic constitutive laws (CLs) have been proposed for isotropic and transversely isotropic soft tissues to model their stress-stretch behavior. Both of them have been implemented in ABAQUS explicit through coding a user-defined material subroutine called VUMAT and the experimental stress-stretch points have been well tracked by the results of FE analyses. It has been demonstrated that the proposed laws make a good description of the viscous nature of tongue tissues. Reliability of the proposed models has been compared with similar nonlinear visco-hyperelastic CLs. Copyright © 2018 Elsevier Ltd. All rights reserved.

  15. A study of gradient strengthening based on a finite-deformation gradient crystal-plasticity model

    NASA Astrophysics Data System (ADS)

    Pouriayevali, Habib; Xu, Bai-Xiang

    2017-11-01

    A comprehensive study on a finite-deformation gradient crystal-plasticity model which has been derived based on Gurtin's framework (Int J Plast 24:702-725, 2008) is carried out here. This systematic investigation on the different roles of governing components of the model represents the strength of this framework in the prediction of a wide range of hardening behaviors as well as rate-dependent and scale-variation responses in a single crystal. The model is represented in the reference configuration for the purpose of numerical implementation and then implemented in the FEM software ABAQUS via a user-defined subroutine (UEL). Furthermore, a function of accumulation rates of dislocations is employed and viewed as a measure of formation of short-range interactions. Our simulation results reveal that the dissipative gradient strengthening can be identified as a source of isotropic-hardening behavior, which may represent the effect of irrecoverable work introduced by Gurtin and Ohno (J Mech Phys Solids 59:320-343, 2011). Here, the variation of size dependency at different magnitude of a rate-sensitivity parameter is also discussed. Moreover, an observation of effect of a distinctive feature in the model which explains the effect of distortion of crystal lattice in the reference configuration is reported in this study for the first time. In addition, plastic flows in predefined slip systems and expansion of accumulation of GNDs are distinctly observed in varying scales and under different loading conditions.

  16. Hydrostatic Stress Effect on the Yield Behavior of Inconel 100

    NASA Technical Reports Server (NTRS)

    Allen, Phillip A.; Wilson, Christopher D.

    2003-01-01

    Classical metal plasticity theory assumes that hydrostatic stress has negligible effect on the yield and postyield behavior of metals. Recent reexaminations of classical theory have revealed a significant effect of hydrostatic stress on the yield behavior of various geometries. Fatigue tests and nonlinear finite element analyses (FEA) of Inconel 100 (IN100) equal-arm bend specimens and new monotonic tests and nonlinear finite element analyses of IN100 smooth tension, smooth compression, and double-edge notch tension (DENT) test specimens have revealed the effect of internal hydrostatic tensile stresses on yielding. Nonlinear FEA using the von Mises (yielding is independent of hydrostatic stress) and the Drucker-Prager (yielding is linearly dependent on hydrostatic stress) yield functions were performed. A new FEA constitutive model was developed that incorporates a pressure-dependent yield function with combined multilinear kinematic and multilinear isotropic hardening using the ABAQUS user subroutine (UMAT) utility. In all monotonic tensile test cases, the von Mises constitutive model, overestimated the load for a given displacement or strain. Considering the failure displacements or strains for the DENT specimen, the Drucker-Prager FEM s predicted loads that were approximately 3% lower than the von Mises values. For the failure loads, the Drucker Prager FEM s predicted strains that were up to 35% greater than the von Mises values. Both the Drucker-Prager model and the von Mises model performed equally-well in simulating the equal-arm bend fatigue test.

  17. The use of three-parameter rating table lookup programs, RDRAT and PARM3, in hydraulic flow models

    USGS Publications Warehouse

    Sanders, C.L.

    1995-01-01

    Subroutines RDRAT and PARM3 enable computer programs such as the BRANCH open-channel unsteady-flow model to route flows through or over combinations of critical-flow sections, culverts, bridges, road- overflow sections, fixed spillways, and(or) dams. The subroutines also obstruct upstream flow to simulate operation of flapper-type tide gates. A multiplier can be applied by date and time to simulate varying numbers of tide gates being open or alternative construction scenarios for multiple culverts. The subroutines use three-parameter (headwater, tailwater, and discharge) rating table lookup methods. These tables may be manually prepared using other programs that do step-backwater computations or compute flow through bridges and culverts or over dams. The subroutine, therefore, precludes the necessity of incorporating considerable hydraulic computational code into the client program, and provides complete flexibility for users of the model for routing flow through almost any affixed structure or combination of structures. The subroutines are written in Fortran 77 language, and have minimal exchange of information with the BRANCH model or other possible client programs. The report documents the interpolation methodology, data input requirements, and software.

  18. Research flight software engineering and MUST, an integrated system of support tools

    NASA Technical Reports Server (NTRS)

    Straeter, T. A.; Foudriat, E. C.; Will, R. W.

    1977-01-01

    Consideration is given to software development to support NASA flight research. The Multipurpose User-Oriented Software Technology (MUST) program, designed to integrate digital systems into flight research, is discussed. Particular attention is given to the program's special interactive user interface, subroutine library, assemblers, compiler, automatic documentation tools, and test and simulation subsystems.

  19. SIVA/DIVA- INITIAL VALUE ORDINARY DIFFERENTIAL EQUATION SOLUTION VIA A VARIABLE ORDER ADAMS METHOD

    NASA Technical Reports Server (NTRS)

    Krogh, F. T.

    1994-01-01

    The SIVA/DIVA package is a collection of subroutines for the solution of ordinary differential equations. There are versions for single precision and double precision arithmetic. These solutions are applicable to stiff or nonstiff differential equations of first or second order. SIVA/DIVA requires fewer evaluations of derivatives than other variable order Adams predictor-corrector methods. There is an option for the direct integration of second order equations which can make integration of trajectory problems significantly more efficient. Other capabilities of SIVA/DIVA include: monitoring a user supplied function which can be separate from the derivative; dynamically controlling the step size; displaying or not displaying output at initial, final, and step size change points; saving the estimated local error; and reverse communication where subroutines return to the user for output or computation of derivatives instead of automatically performing calculations. The user must supply SIVA/DIVA with: 1) the number of equations; 2) initial values for the dependent and independent variables, integration stepsize, error tolerance, etc.; and 3) the driver program and operational parameters necessary for subroutine execution. SIVA/DIVA contains an extensive diagnostic message library should errors occur during execution. SIVA/DIVA is written in FORTRAN 77 for batch execution and is machine independent. It has a central memory requirement of approximately 120K of 8 bit bytes. This program was developed in 1983 and last updated in 1987.

  20. GASP- General Aviation Synthesis Program. Volume 6: Performance

    NASA Technical Reports Server (NTRS)

    Hague, D.

    1978-01-01

    Aircraft performance modeling requires consideration of propulsion, aerodynamics, and weight characteristics. Eleven subroutines used in modeling aircraft performance are presented and their interactions considered. Manuals for performance model users and programmers are included.

  1. Micromechanical modeling of rate-dependent behavior of Connective tissues.

    PubMed

    Fallah, A; Ahmadian, M T; Firozbakhsh, K; Aghdam, M M

    2017-03-07

    In this paper, a constitutive and micromechanical model for prediction of rate-dependent behavior of connective tissues (CTs) is presented. Connective tissues are considered as nonlinear viscoelastic material. The rate-dependent behavior of CTs is incorporated into model using the well-known quasi-linear viscoelasticity (QLV) theory. A planar wavy representative volume element (RVE) is considered based on the tissue microstructure histological evidences. The presented model parameters are identified based on the available experiments in the literature. The presented constitutive model introduced to ABAQUS by means of UMAT subroutine. Results show that, monotonic uniaxial test predictions of the presented model at different strain rates for rat tail tendon (RTT) and human patellar tendon (HPT) are in good agreement with experimental data. Results of incremental stress-relaxation test are also presented to investigate both instantaneous and viscoelastic behavior of connective tissues. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Computer simulations of austenite decomposition of microalloyed 700 MPa steel during cooling

    NASA Astrophysics Data System (ADS)

    Pohjonen, Aarne; Paananen, Joni; Mourujärvi, Juho; Manninen, Timo; Larkiola, Jari; Porter, David

    2018-05-01

    We present computer simulations of austenite decomposition to ferrite and bainite during cooling. The phase transformation model is based on Johnson-Mehl-Avrami-Kolmogorov type equations. The model is parameterized by numerical fitting to continuous cooling data obtained with Gleeble thermo-mechanical simulator and it can be used for calculation of the transformation behavior occurring during cooling along any cooling path. The phase transformation model has been coupled with heat conduction simulations. The model includes separate parameters to account for the incubation stage and for the kinetics after the transformation has started. The incubation time is calculated with inversion of the CCT transformation start time. For heat conduction simulations we employed our own parallelized 2-dimensional finite difference code. In addition, the transformation model was also implemented as a subroutine in commercial finite-element software Abaqus which allows for the use of the model in various engineering applications.

  3. Predicting Failure Progression and Failure Loads in Composite Open-Hole Tension Coupons

    NASA Technical Reports Server (NTRS)

    Arunkumar, Satyanarayana; Przekop, Adam

    2010-01-01

    Failure types and failure loads in carbon-epoxy [45n/90n/-45n/0n]ms laminate coupons with central circular holes subjected to tensile load are simulated using progressive failure analysis (PFA) methodology. The progressive failure methodology is implemented using VUMAT subroutine within the ABAQUS(TradeMark)/Explicit nonlinear finite element code. The degradation model adopted in the present PFA methodology uses an instantaneous complete stress reduction (COSTR) approach to simulate damage at a material point when failure occurs. In-plane modeling parameters such as element size and shape are held constant in the finite element models, irrespective of laminate thickness and hole size, to predict failure loads and failure progression. Comparison to published test data indicates that this methodology accurately simulates brittle, pull-out and delamination failure types. The sensitivity of the failure progression and the failure load to analytical loading rates and solvers precision is demonstrated.

  4. IPLIB (Image processing library) user's manual

    NASA Technical Reports Server (NTRS)

    Faulcon, N. D.; Monteith, J. H.; Miller, K.

    1985-01-01

    IPLIB is a collection of HP FORTRAN 77 subroutines and functions that facilitate the use of a COMTAL image processing system driven by an HP-1000 computer. It is intended for programmers who want to use the HP 1000 to drive the COMTAL Vision One/20 system. It is assumed that the programmer knows HP 1000 FORTRAN 77 or at least one FORTRAN dialect. It is also assumed that the programmer has some familiarity with the COMTAL Vision One/20 system.

  5. Computer program for determining the thermodynamic properties of Freon refrigerants

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Riemer, D.H.; Jacobs, H.R.; Boehm, R.F.

    1977-12-01

    This program was written to be used as a subroutine. The program determines the thermodynamics of Freon refrigerants. The following refrigerants can be analyzed F-11, F-12, F-13, F-14, F-21, F-22, F-23, F-113, and F-114. The subroutine can evaluate a thermodynamic state for these refrigerants given any of the following pairs of state quantities: pressure and quality, pressure and entropy, pressure and enthalpy, temperature and quality, temperature and specific volume, and temperature and pressure. These six pairs of knowns allow the user to analyze any thermodynamic cycle utilizing a refrigerant as the working fluid. The Downing form of the Martin equationmore » of state was used. This report contains a brief description, flow chart and listing of all subroutines required.« less

  6. Computer program for determining the thermodynamic properties of freon refrigerants

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Riemer, D.H.; Jacobs, H.R.; Boehm, R.F.

    1976-07-01

    This program was written to be used as a subroutine. The program determines the thermodynamics of Freon refrigerants. The following refrigerants can be analyzed F-11, F-12, F-13, F-14, F-21, F-22, F-23, F-113, and F-114. The subroutine can evaluate a thermodynamic state for these refrigerants given any of the following pairs of state quantities: pressure and quality, pressure and entropy, pressure and enthalpy, temperature and quality, temperature and specific volume and temperature and pressure. These six pairs of knowns allow the user to analyze any thermodynamic cycle utilizing a refrigerant as the working fluid. The Downing form of the Martin equationmore » of state was used. A brief description, flow chart, and listing of all subroutines required are presented.« less

  7. Micromechanics and constitutive modeling of connective soft tissues.

    PubMed

    Fallah, A; Ahmadian, M T; Firozbakhsh, K; Aghdam, M M

    2016-07-01

    In this paper, a micromechanical model for connective soft tissues based on the available histological evidences is developed. The proposed model constituents i.e. collagen fibers and ground matrix are considered as hyperelastic materials. The matrix material is assumed to be isotropic Neo-Hookean while the collagen fibers are considered to be transversely isotropic hyperelastic. In order to take into account the effects of tissue structure in lower scales on the macroscopic behavior of tissue, a strain energy density function (SEDF) is developed for collagen fibers based on tissue hierarchical structure. Macroscopic response and properties of tissue are obtained using the numerical homogenization method with the help of ABAQUS software. The periodic boundary conditions and the proposed constitutive models are implemented into ABAQUS using the DISP and the UMAT subroutines, respectively. The existence of the solution and stable material behavior of proposed constitutive model for collagen fibers are investigated based on the poly-convexity condition. Results of the presented micromechanics model for connective tissues are compared and validated with available experimental data. Effects of geometrical and material parameters variation at microscale on macroscopic mechanical behavior of tissues are investigated. The results show that decrease in collagen content of the connective tissues like the tendon due to diseases leads 20% more stretch than healthy tissue under the same load which can results in connective tissue malfunction and hypermobility in joints. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. The Effect of Delamination on Damage Path and Failure Load Prediction for Notched Composite Laminates

    NASA Technical Reports Server (NTRS)

    Satyanarayana, Arunkumar; Bogert, Philip B.; Chunchu, Prasad B.

    2007-01-01

    The influence of delamination on the progressing damage path and initial failure load in composite laminates is investigated. Results are presented from a numerical and an experimental study of center-notched tensile-loaded coupons. The numerical study includes two approaches. The first approach considers only intralaminar (fiber breakage and matrix cracking) damage modes in calculating the progression of the damage path. In the second approach, the model is extended to consider the effect of interlaminar (delamination) damage modes in addition to the intralaminar damage modes. The intralaminar damage is modeled using progressive damage analysis (PDA) methodology implemented with the VUMAT subroutine in the ABAQUS finite element code. The interlaminar damage mode has been simulated using cohesive elements in ABAQUS. In the experimental study, 2-3 specimens each of two different stacking sequences of center-notched laminates are tensile loaded. The numerical results from the two different modeling approaches are compared with each other and the experimentally observed results for both laminate types. The comparisons reveal that the second modeling approach, where the delamination damage mode is included together with the intralaminar damage modes, better simulates the experimentally observed damage modes and damage paths, which were characterized by splitting failures perpendicular to the notch tips in one or more layers. Additionally, the inclusion of the delamination mode resulted in a better prediction of the loads at which the failure took place, which were higher than those predicted by the first modeling approach which did not include delaminations.

  9. User Need Satisfaction as a Basis for Tactical Airlift Scheduling.

    DTIC Science & Technology

    1984-03-01

    Yr.. Mo.. Day) 1S. PAGE COUNT MS Thesis FROM _ TO 1984 March 220 16. SUPPLEMENTARY NOTATION gym . Daan for Resoarch and Prolusloud ou -t, :... e...SUBROUTINE ROUTE. IT DOES THIS BY TESTING EACH MISSION C- FOR SCHEDULING CONFI ICTS . IF THE NUMBER OF EXPECTED C- CONFLICTS EXCEEDS A MINIMUM VALUE, THE

  10. Simulation of flexible appendage interactions with Mariner Venus/Mercury attitude control and science platform pointing

    NASA Technical Reports Server (NTRS)

    Fleischer, G. E.

    1973-01-01

    A new computer subroutine, which solves the attitude equations of motion for any vehicle idealized as a topological tree of hinge-connected rigid bodies, is used to simulate and analyze science instrument pointing control interaction with a flexible Mariner Venus/Mercury (MVM) spacecraft. The subroutine's user options include linearized or partially linearized hinge-connected models whose computational advantages are demonstrated for the MVM problem. Results of the pointing control/flexible vehicle interaction simulations, including imaging experiment pointing accuracy predictions and implications for MVM science sequence planning, are described in detail.

  11. Application Portable Parallel Library

    NASA Technical Reports Server (NTRS)

    Cole, Gary L.; Blech, Richard A.; Quealy, Angela; Townsend, Scott

    1995-01-01

    Application Portable Parallel Library (APPL) computer program is subroutine-based message-passing software library intended to provide consistent interface to variety of multiprocessor computers on market today. Minimizes effort needed to move application program from one computer to another. User develops application program once and then easily moves application program from parallel computer on which created to another parallel computer. ("Parallel computer" also include heterogeneous collection of networked computers). Written in C language with one FORTRAN 77 subroutine for UNIX-based computers and callable from application programs written in C language or FORTRAN 77.

  12. Frequency Domain Identification Toolbox

    NASA Technical Reports Server (NTRS)

    Horta, Lucas G.; Juang, Jer-Nan; Chen, Chung-Wen

    1996-01-01

    This report documents software written in MATLAB programming language for performing identification of systems from frequency response functions. MATLAB is a commercial software environment which allows easy manipulation of data matrices and provides other intrinsic matrix functions capabilities. Algorithms programmed in this collection of subroutines have been documented elsewhere but all references are provided in this document. A main feature of this software is the use of matrix fraction descriptions and system realization theory to identify state space models directly from test data. All subroutines have templates for the user to use as guidelines.

  13. A User’s Guide to the SEVP (Stabilized Error Vector Propagation) Solver: An Efficient Direct Solver for Elliptic Partial Differential Equations

    DTIC Science & Technology

    1989-04-13

    19 5.3 The Solution, BSM2 , BSM3 . ...................................... 21 6. Description of test example...are modified for the boundary conditions. The sections on the preprocessor subroutine BSM1 and the solution subroutines BSM2 , BSM3 may be skipped by...interior row j = N-1 to the solution error C5 on the second row j = IE(2) of the last block, so that P3 = C5 R31 (5.18) 20 5.3 The Solution. BSM2

  14. SUTIL: system utilities routines programmer's reference manual

    NASA Technical Reports Server (NTRS)

    Harper, D.

    1976-01-01

    A package of FORTRAN callable subroutines which allows efficient communication of data between users and programs is described. Proper utilization of the SUTIL package to reduce program core requirements and expedite program development is emphasized.

  15. AIRWAR II User’s Manual.

    DTIC Science & Technology

    1984-04-17

    3 asS -gag a coo 4; ; liJ J j jj; 0000 4.3 0 C, coo ac 0 cc 00 0j0i0 000 000; 0004- -’a -- fta LL. 000 00s 0 ~ m 0e00@0000 ccPo 000 coo oo J ~ 000 1...maintenance variables are set up in subroutine lE DIT from input values. For primary bases: DD -DMD MTTR(ij,id) FMD " MT ¥fg(ij, id ) F - F A(ij,id) where

  16. Mathematical computer programs: A compilation

    NASA Technical Reports Server (NTRS)

    1972-01-01

    Computer programs, routines, and subroutines for aiding engineers, scientists, and mathematicians in direct problem solving are presented. Also included is a group of items that affords the same users greater flexibility in the use of software.

  17. NEWSUMT: A FORTRAN program for inequality constrained function minimization, users guide

    NASA Technical Reports Server (NTRS)

    Miura, H.; Schmit, L. A., Jr.

    1979-01-01

    A computer program written in FORTRAN subroutine form for the solution of linear and nonlinear constrained and unconstrained function minimization problems is presented. The algorithm is the sequence of unconstrained minimizations using the Newton's method for unconstrained function minimizations. The use of NEWSUMT and the definition of all parameters are described.

  18. KRASH 85 User’s Guide - Input/Output Format.

    DTIC Science & Technology

    1985-07-01

    speaking, any significant .crror in the model will result in a very large value for EPSILON (1>0.1) or will ca;use the NASTRAN solution to terminate with...with NASTRAN ) * A comprehensive energy balance, * Center of gravity (c.g.) displacement, velocity, acceleration and force time histories * Revised...initial conditions subroutine (combined with NASTRAN ) * A comprehensive energy balance * Center of gravity (e.g.) displacement, velocity, acceleration and

  19. Harwell Subroutine Library. A Catalogue of Subroutines (1973),

    DTIC Science & Technology

    1973-07-01

    up the equations AT Ax = ATb. There may be more than one right-hand size. Remark: If the solution is required see MAO9A. Versions: MAOA ; MAOBAD. Calls...Hermitian MEO8A source decks-modification of OEOIA real gene .’al to Hessenberg sparsity pattern TDO2A MC08A, MCI4A spherical co-ordinates GAOIA real

  20. Analysis of field test data on residential heating and cooling

    NASA Astrophysics Data System (ADS)

    Talbert, S. G.

    1980-12-01

    The computer program using field site data collected on 48 homes located in six cities in different climatic regions of the United States is discussed. In addition, a User's Guide was prepared for the computer program which is contained in a separate two-volume document entitled User's Guide for REAP: Residential Energy Analysis Program. Feasibility studies were conducted pertaining to potential improvements for REAP, including: the addition of an oil-furnace model; improving the infiltration subroutine; adding active and/or passive solar subroutines; incorporating a thermal energy storage model; and providing dual HVAC systems (e.g., heat pump-gas furnace). The purpose of REAP is to enable building designers and energy analysts to evaluate how such factors as building design, weather conditions, internal heat loads, and HVAC equipment performance, influence the energy requirements of residential buildings.

  1. Chemkin-II: A Fortran chemical kinetics package for the analysis of gas-phase chemical kinetics

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kee, R.J.; Rupley, F.M.; Miller, J.A.

    1989-09-01

    This document is the user's manual for the second-generation Chemkin package. Chemkin is a software package for whose purpose is to facilitate the formation, solution, and interpretation of problems involving elementary gas-phase chemical kinetics. It provides an especially flexible and powerful tool for incorporating complex chemical kinetics into simulations of fluid dynamics. The package consists of two major software components: an Interpreter and Gas-Phase Subroutine Library. The Interpreter is a program that reads a symbolic description of an elementary, user-specified chemical reaction mechanism. One output from the Interpreter is a data file that forms a link to the Gas-Phase Subroutinemore » Library. This library is a collection of about 100 highly modular Fortran subroutines that may be called to return information on equation of state, thermodynamic properties, and chemical production rates.« less

  2. Hyperprolactinaemia as a result of immaturity or regression: the concept of maternal subroutine. A new model of psychoendocrine interactions.

    PubMed

    Sobrinho, L G; Almeida-Costa, J M

    1992-01-01

    Pathological hyperprolactinaemia (PH) is significantly associated with: (1) paternal deprivation during childhood, (2) depression, (3) non-specific symptoms including obesity and weight gain. The clinical onset of the symptoms often follows pregnancy or a loss. Prolactin is an insulin antagonist which does not promote weight gain. Hyperprolactinaemia and increased metabolic efficiency are parts of a system of interdependent behavioural and metabolic mechanisms necessary for the care of the young. We call this system, which is available as a whole package, maternal subroutine (MS). An important number of cases of PH are due to activation of the MS that is not induced by pregnancy. The same occurs in surrogate maternity and in some animal models. Most women with PH developed a malignant symbiotic relationship with their mothers in the setting of absence, alcoholism or devaluation of the father. These women may regress to early developmental stages to the point that they identify themselves both with their lactating mother and with the nursing infant as has been found in psychoanalysed patients and in the paradigmatic condition of pseudopregnancy. Such regression can be associated with activation of the MS. Prolactinomas represent the extreme of the spectrum of PH and may result from somatic mutations occurring in hyperstimulated lactotrophs.

  3. New microscale constitutive model of human trabecular bone based on depth sensing indentation technique.

    PubMed

    Pawlikowski, Marek; Jankowski, Krzysztof; Skalski, Konstanty

    2018-05-30

    A new constitutive model for human trabecular bone is presented in the present study. As the model is based on indentation tests performed on single trabeculae it is formulated in a microscale. The constitutive law takes into account non-linear viscoelasticity of the tissue. The elastic response is described by the hyperelastic Mooney-Rivlin model while the viscoelastic effects are considered by means of the hereditary integral in which stress depends on both time and strain. The material constants in the constitutive equation are identified on the basis of the stress relaxation tests and the indentation tests using curve-fitting procedure. The constitutive model is implemented into finite element package Abaqus ® by means of UMAT subroutine. The curve-fitting error is low and the viscoelastic behaviour of the tissue predicted by the proposed constitutive model corresponds well to the realistic response of the trabecular bone. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

  4. On the mechanics of growing thin biological membranes

    NASA Astrophysics Data System (ADS)

    Rausch, Manuel K.; Kuhl, Ellen

    2014-02-01

    Despite their seemingly delicate appearance, thin biological membranes fulfill various crucial roles in the human body and can sustain substantial mechanical loads. Unlike engineering structures, biological membranes are able to grow and adapt to changes in their mechanical environment. Finite element modeling of biological growth holds the potential to better understand the interplay of membrane form and function and to reliably predict the effects of disease or medical intervention. However, standard continuum elements typically fail to represent thin biological membranes efficiently, accurately, and robustly. Moreover, continuum models are typically cumbersome to generate from surface-based medical imaging data. Here we propose a computational model for finite membrane growth using a classical midsurface representation compatible with standard shell elements. By assuming elastic incompressibility and membrane-only growth, the model a priori satisfies the zero-normal stress condition. To demonstrate its modular nature, we implement the membrane growth model into the general-purpose non-linear finite element package Abaqus/Standard using the concept of user subroutines. To probe efficiently and robustness, we simulate selected benchmark examples of growing biological membranes under different loading conditions. To demonstrate the clinical potential, we simulate the functional adaptation of a heart valve leaflet in ischemic cardiomyopathy. We believe that our novel approach will be widely applicable to simulate the adaptive chronic growth of thin biological structures including skin membranes, mucous membranes, fetal membranes, tympanic membranes, corneoscleral membranes, and heart valve membranes. Ultimately, our model can be used to identify diseased states, predict disease evolution, and guide the design of interventional or pharmaceutic therapies to arrest or revert disease progression.

  5. A 2D modeling approach for fluid propagation during FE-forming simulation of continuously reinforced composites in wet compression moulding

    NASA Astrophysics Data System (ADS)

    Poppe, Christian; Dörr, Dominik; Henning, Frank; Kärger, Luise

    2018-05-01

    Wet compression moulding (WCM) provides large-scale production potential for continuously fiber reinforced components as a promising alternative to resin transfer moulding (RTM). Lower cycle times are possible due to parallelization of the process steps draping, infiltration and curing during moulding (viscous draping). Experimental and theoretical investigations indicate a strong mutual dependency between the physical mechanisms, which occur during draping and mould filling (fluid-structure-interaction). Thus, key process parameters, like fiber orientation, fiber volume fraction, cavity pressure and the amount and viscosity of the resin are physically coupled. To enable time and cost efficient product and process development throughout all design stages, accurate process simulation tools are desirable. Separated draping and mould filling simulation models, as appropriate for the sequential RTM-process, cannot be applied for the WCM process due to the above outlined physical couplings. Within this study, a two-dimensional Darcy-Propagation-Element (DPE-2D) based on a finite element formulation with additional control volumes (FE/CV) is presented, verified and applied to forming simulation of a generic geometry, as a first step towards a fluid-structure-interaction model taking into account simultaneous resin infiltration and draping. The model is implemented in the commercial FE-Solver Abaqus by means of several user subroutines considering simultaneous draping and 2D-infiltration mechanisms. Darcy's equation is solved with respect to a local fiber orientation. Furthermore, the material model can access the local fluid domain properties to update the mechanical forming material parameter, which enables further investigations on the coupled physical mechanisms.

  6. Influence of Finite Element Size in Residual Strength Prediction of Composite Structures

    NASA Technical Reports Server (NTRS)

    Satyanarayana, Arunkumar; Bogert, Philip B.; Karayev, Kazbek Z.; Nordman, Paul S.; Razi, Hamid

    2012-01-01

    The sensitivity of failure load to the element size used in a progressive failure analysis (PFA) of carbon composite center notched laminates is evaluated. The sensitivity study employs a PFA methodology previously developed by the authors consisting of Hashin-Rotem intra-laminar fiber and matrix failure criteria and a complete stress degradation scheme for damage simulation. The approach is implemented with a user defined subroutine in the ABAQUS/Explicit finite element package. The effect of element size near the notch tips on residual strength predictions was assessed for a brittle failure mode with a parametric study that included three laminates of varying material system, thickness and stacking sequence. The study resulted in the selection of an element size of 0.09 in. X 0.09 in., which was later used for predicting crack paths and failure loads in sandwich panels and monolithic laminated panels. Comparison of predicted crack paths and failure loads for these panels agreed well with experimental observations. Additionally, the element size vs. normalized failure load relationship, determined in the parametric study, was used to evaluate strength-scaling factors for three different element sizes. The failure loads predicted with all three element sizes provided converged failure loads with respect to that corresponding with the 0.09 in. X 0.09 in. element size. Though preliminary in nature, the strength-scaling concept has the potential to greatly reduce the computational time required for PFA and can enable the analysis of large scale structural components where failure is dominated by fiber failure in tension.

  7. Computational predictions of damage propagation preceding dissection of ascending thoracic aortic aneurysms.

    PubMed

    Mousavi, S Jamaleddin; Farzaneh, Solmaz; Avril, Stéphane

    2018-04-01

    Dissections of ascending thoracic aortic aneurysms (ATAAs) cause significant morbidity and mortality worldwide. They occur when a tear in the intima-media of the aorta permits the penetration of the blood and the subsequent delamination and separation of the wall in 2 layers, forming a false channel. To predict computationally the risk of tear formation, stress analyses should be performed layer-specifically and they should consider internal or residual stresses that exist in the tissue. In the present paper, we propose a novel layer-specific damage model based on the constrained mixture theory, which intrinsically takes into account these internal stresses and can predict appropriately the tear formation. The model is implemented in finite-element commercial software Abaqus coupled with user material subroutine. Its capability is tested by applying it to the simulation of different exemplary situations, going from in vitro bulge inflation experiments on aortic samples to in vivo overpressurizing of patient-specific ATAAs. The simulations reveal that damage correctly starts from the intimal layer (luminal side) and propagates across the media as a tear but never hits the adventitia. This scenario is typically the first stage of development of an acute dissection, which is predicted for pressures of about 2.5 times the diastolic pressure by the model after calibrating the parameters against experimental data performed on collected ATAA samples. Further validations on a larger cohort of patients should hopefully confirm the potential of the model in predicting patient-specific damage evolution and possible risk of dissection during aneurysm growth for clinical applications. Copyright © 2017 John Wiley & Sons, Ltd.

  8. Enhanced Schapery Theory Software Development for Modeling Failure of Fiber-Reinforced Laminates

    NASA Technical Reports Server (NTRS)

    Pineda, Evan J.; Waas, Anthony M.

    2013-01-01

    Progressive damage and failure analysis (PDFA) tools are needed to predict the nonlinear response of advanced fiber-reinforced composite structures. Predictive tools should incorporate the underlying physics of the damage and failure mechanisms observed in the composite, and should utilize as few input parameters as possible. The purpose of the Enhanced Schapery Theory (EST) was to create a PDFA tool that operates in conjunction with a commercially available finite element (FE) code (Abaqus). The tool captures the physics of the damage and failure mechanisms that result in the nonlinear behavior of the material, and the failure methodology employed yields numerical results that are relatively insensitive to changes in the FE mesh. The EST code is written in Fortran and compiled into a static library that is linked to Abaqus. A Fortran Abaqus UMAT material subroutine is used to facilitate the communication between Abaqus and EST. A clear distinction between damage and failure is imposed. Damage mechanisms result in pre-peak nonlinearity in the stress strain curve. Four internal state variables (ISVs) are utilized to control the damage and failure degradation. All damage is said to result from matrix microdamage, and a single ISV marks the micro-damage evolution as it is used to degrade the transverse and shear moduli of the lamina using a set of experimentally obtainable matrix microdamage functions. Three separate failure ISVs are used to incorporate failure due to fiber breakage, mode I matrix cracking, and mode II matrix cracking. Failure initiation is determined using a failure criterion, and the evolution of these ISVs is controlled by a set of traction-separation laws. The traction separation laws are postulated such that the area under the curves is equal to the fracture toughness of the material associated with the corresponding failure mechanism. A characteristic finite element length is used to transform the traction-separation laws into stress-strain laws

  9. Interim user's manual for boundary layer integral matrix procedure, version J

    NASA Technical Reports Server (NTRS)

    Evans, R. M.; Morse, H. L.

    1974-01-01

    A computer program for analyzing two dimensional and axisymmetric nozzle performance with a variety of wall boundary conditions is described. The program has been developed for application to rocket nozzle problems. Several aids to usage of the program and two auxiliary subroutines are provided. Some features of the output are described and three sample cases are included.

  10. Explicit and implicit springback simulation in sheet metal forming using fully coupled ductile damage and distortional hardening model

    NASA Astrophysics Data System (ADS)

    Yetna n'jock, M.; Houssem, B.; Labergere, C.; Saanouni, K.; Zhenming, Y.

    2018-05-01

    The springback is an important phenomenon which accompanies the forming of metallic sheets especially for high strength materials. A quantitative prediction of springback becomes very important for newly developed material with high mechanical characteristics. In this work, a numerical methodology is developed to quantify this undesirable phenomenon. This methodoly is based on the use of both explicit and implicit finite element solvers of Abaqus®. The most important ingredient of this methodology consists on the use of highly predictive mechanical model. A thermodynamically-consistent, non-associative and fully anisotropic elastoplastic constitutive model strongly coupled with isotropic ductile damage and accounting for distortional hardening is then used. An algorithm for local integration of the complete set of the constitutive equations is developed. This algorithm considers the rotated frame formulation (RFF) to ensure the incremental objectivity of the model in the framework of finite strains. This algorithm is implemented in both explicit (Abaqus/Explicit®) and implicit (Abaqus/Standard®) solvers of Abaqus® through the users routine VUMAT and UMAT respectively. The implicit solver of Abaqus® has been used to study spingback as it is generally a quasi-static unloading. In order to compare the methods `efficiency, the explicit method (Dynamic Relaxation Method) proposed by Rayleigh has been also used for springback prediction. The results obtained within U draw/bending benchmark are studied, discussed and compared with experimental results as reference. Finally, the purpose of this work is to evaluate the reliability of different methods predict efficiently springback in sheet metal forming.

  11. Guide to using Cuechart, Tellagraf, and Disspla at ANL

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bertoncini, P.J.; Thommes, M.M.

    1986-01-01

    Guide to Curchart, Tellagraf, and Disspla at ANL provides information necessary for using the three ISSCO graphics packages at Argonne: Cuechart is a cue-and-response program available in CMS that aids users in creating bar charts, line charts, pie charts, and word charts. It is appropriate for users with little or no previous graphics experience. Cuechart provides much of the capability of Tellagraf without the user's having to learn Tellagraf commands. Tellagraf is a more powerful, easy-to-use graphics package also available in CMS. With a little training, scientists, administrators, and secretaries can produce sophisticated publication-quality log or linear plots, bar charts,more » pie charts, tables, or posters. Disspla is a more versatile and sophisticated graphics package. It is available in both CMS and batch and consists of several hundred Fortran-callable and PL/I-callable subroutines that will enable you to obtain professional quality plots. In addition to log or linear plots, bar charts, pie charts, and pages of text, Disspla provides subroutines for contour plots, 3-D plots, and world maps.« less

  12. ABSIM. Simulation of Absorption Systems in Flexible and Modular Form

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Grossman, G.

    1994-06-01

    The computer code has been developed for simulation of absorption systems at steady-state in a flexible and modular form, making it possible to investigate various cycle configurations with different working fluids. The code is based on unit subroutines containing the governing equations for the system`s components. When all the equations have been established, a mathematical solver routine is employed to solve them simultaneously. Property subroutines contained in a separate data base serve to provide thermodynamic properties of the working fluids. The code is user-oriented and requires a relatively simple input containing the given operating conditions and the working fluid atmore » each state point. the user conveys to the computer an image of the cycle by specifying the different components and their interconnections. Based on this information, the program calculates the temperature, flowrate, concentration, pressure and vapor fraction at each state point in the system and the heat duty at each unit, from which the coefficient of performance may be determined. A graphical user-interface is provided to facilitate interactive input and study of the output.« less

  13. ABSIM. Simulation of Absorption Systems in Flexible and Modular Form

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Grossman, G.

    1994-06-01

    The computer code has been developed for simulation of absorption systems at steady-state in a flexible and modular form, making it possible to investigate various cycle configurations with different working fluids. The code is based on unit subroutines containing the governing equations for the system's components. When all the equations have been established, a mathematical solver routine is employed to solve them simultaneously. Property subroutines contained in a separate data base serve to provide thermodynamic properties of the working fluids. The code is user-oriented and requires a relatively simple input containing the given operating conditions and the working fluid atmore » each state point. the user conveys to the computer an imagev of the cycle by specifying the different components and their interconnections. Based on this information, the program calculates the temperature, flowrate, concentration, pressure and vapor fraction at each state point in the system and the heat duty at each unit, from which the coefficient of performance may be determined. A graphical user-interface is provided to fcilitate interactive input and study of the output.« less

  14. Preliminary design methods for fiber reinforced composite structures employing a personal computer

    NASA Technical Reports Server (NTRS)

    Eastlake, C. N.

    1986-01-01

    The objective of this project was to develop a user-friendly interactive computer program to be used as an analytical tool by structural designers. Its intent was to do preliminary, approximate stress analysis to help select or verify sizing choices for composite structural members. The approach to the project was to provide a subroutine which uses classical lamination theory to predict an effective elastic modulus for a laminate of arbitrary material and ply orientation. This effective elastic modulus can then be used in a family of other subroutines which employ the familiar basic structural analysis methods for isotropic materials. This method is simple and convenient to use but only approximate, as is appropriate for a preliminary design tool which will be subsequently verified by more sophisticated analysis. Additional subroutines have been provided to calculate laminate coefficient of thermal expansion and to calculate ply-by-ply strains within a laminate.

  15. PENGEOM-A general-purpose geometry package for Monte Carlo simulation of radiation transport in material systems defined by quadric surfaces

    NASA Astrophysics Data System (ADS)

    Almansa, Julio; Salvat-Pujol, Francesc; Díaz-Londoño, Gloria; Carnicer, Artur; Lallena, Antonio M.; Salvat, Francesc

    2016-02-01

    The Fortran subroutine package PENGEOM provides a complete set of tools to handle quadric geometries in Monte Carlo simulations of radiation transport. The material structure where radiation propagates is assumed to consist of homogeneous bodies limited by quadric surfaces. The PENGEOM subroutines (a subset of the PENELOPE code) track particles through the material structure, independently of the details of the physics models adopted to describe the interactions. Although these subroutines are designed for detailed simulations of photon and electron transport, where all individual interactions are simulated sequentially, they can also be used in mixed (class II) schemes for simulating the transport of high-energy charged particles, where the effect of soft interactions is described by the random-hinge method. The definition of the geometry and the details of the tracking algorithm are tailored to optimize simulation speed. The use of fuzzy quadric surfaces minimizes the impact of round-off errors. The provided software includes a Java graphical user interface for editing and debugging the geometry definition file and for visualizing the material structure. Images of the structure are generated by using the tracking subroutines and, hence, they describe the geometry actually passed to the simulation code.

  16. User-defined functions in the Arden Syntax: An extension proposal.

    PubMed

    Karadimas, Harry; Ebrahiminia, Vahid; Lepage, Eric

    2015-12-11

    The Arden Syntax is a knowledge-encoding standard, started in 1989, and now in its 10th revision, maintained by the health level seven (HL7) organization. It has constructs borrowed from several language concepts that were available at that time (mainly the HELP hospital information system and the Regenstrief medical record system (RMRS), but also the Pascal language, functional languages and the data structure of frames, used in artificial intelligence). The syntax has a rationale for its constructs, and has restrictions that follow this rationale. The main goal of the Standard is to promote knowledge sharing, by avoiding the complexity of traditional programs, so that a medical logic module (MLM) written in the Arden Syntax can remain shareable and understandable across institutions. One of the restrictions of the syntax is that you cannot define your own functions and subroutines inside an MLM. An MLM can, however, call another MLM, where this MLM will serve as a function. This will add an additional dependency between MLMs, a known criticism of the Arden Syntax knowledge model. This article explains why we believe the Arden Syntax would benefit from a construct for user-defined functions, discusses the need, the benefits and the limitations of such a construct. We used the recent grammar of the Arden Syntax v.2.10, and both the Arden Syntax standard document and the Arden Syntax Rationale article as guidelines. We gradually introduced production rules to the grammar. We used the CUP parsing tool to verify that no ambiguities were detected. A new grammar was produced, that supports user-defined functions. 22 production rules were added to the grammar. A parser was built using the CUP parsing tool. A few examples are given to illustrate the concepts. All examples were parsed correctly. It is possible to add user-defined functions to the Arden Syntax in a way that remains coherent with the standard. We believe that this enhances the readability and the robustness

  17. In Search of a Time Efficient Approach to Crack and Delamination Growth Predictions in Composites

    NASA Technical Reports Server (NTRS)

    Krueger, Ronald; Carvalho, Nelson

    2016-01-01

    Analysis benchmarking was used to assess the accuracy and time efficiency of algorithms suitable for automated delamination growth analysis. First, the Floating Node Method (FNM) was introduced and its combination with a simple exponential growth law (Paris Law) and Virtual Crack Closure technique (VCCT) was discussed. Implementation of the method into a user element (UEL) in Abaqus/Standard(Registered TradeMark) was also presented. For the assessment of growth prediction capabilities, an existing benchmark case based on the Double Cantilever Beam (DCB) specimen was briefly summarized. Additionally, the development of new benchmark cases based on the Mixed-Mode Bending (MMB) specimen to assess the growth prediction capabilities under mixed-mode I/II conditions was discussed in detail. A comparison was presented, in which the benchmark cases were used to assess the existing low-cycle fatigue analysis tool in Abaqus/Standard(Registered TradeMark) in comparison to the FNM-VCCT fatigue growth analysis implementation. The low-cycle fatigue analysis tool in Abaqus/Standard(Registered TradeMark) was able to yield results that were in good agreement with the DCB benchmark example. Results for the MMB benchmark cases, however, only captured the trend correctly. The user element (FNM-VCCT) always yielded results that were in excellent agreement with all benchmark cases, at a fraction of the analysis time. The ability to assess the implementation of two methods in one finite element code illustrated the value of establishing benchmark solutions.

  18. CHEMKIN-III: A FORTRAN chemical kinetics package for the analysis of gas-phase chemical and plasma kinetics

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kee, R.J.; Rupley, F.M.; Meeks, E.

    1996-05-01

    This document is the user`s manual for the third-generation CHEMKIN package. CHEMKIN is a software package whose purpose is to facilitate the formation, solution, and interpretation of problems involving elementary gas-phase chemical kinetics. It provides a flexible and powerful tool for incorporating complex chemical kinetics into simulations of fluid dynamics. The package consists of two major software components: an Interpreter and a Gas-Phase Subroutine Library. The Interpreter is a program that reads a symbolic description of an elementary, user-specified chemical reaction mechanism. One output from the Interpreter is a data file that forms a link to the Gas-Phase Subroutine Library.more » This library is a collection of about 100 highly modular FORTRAN subroutines that may be called to return information on equations of state, thermodynamic properties, and chemical production rates. CHEMKIN-III includes capabilities for treating multi-fluid plasma systems, that are not in thermal equilibrium. These new capabilities allow researchers to describe chemistry systems that are characterized by more than one temperature, in which reactions may depend on temperatures associated with different species; i.e. reactions may be driven by collisions with electrons, ions, or charge-neutral species. These new features have been implemented in such a way as to require little or no changes to CHEMKIN implementation for systems in thermal equilibrium, where all species share the same gas temperature. CHEMKIN-III now has the capability to handle weakly ionized plasma chemistry, especially for application related to advanced semiconductor processing.« less

  19. Simulation of gamma-ray spectra for a variety of user-specified detector designs

    NASA Technical Reports Server (NTRS)

    Rester, A. C., Jr.

    1994-01-01

    The gamma-ray spectrum simulation program BSIMUL was designed to allow the operator to follow the path of a gamma-ray through a detector, shield and collimator whose dimensions are entered by the operator. It can also be used to simulate spectra that would be generated by a detector. Several improvements have been made to the program within the last few months. The detector, shield and collimator dimensions can now be entered through an interactive menu whose options are discussed below. In addition, spectra containing more than one gamma-ray energy can now be generated with the menu - for isotopes listed in the program. Adding isotopes to the main routine is also quite easy. Subroutines have been added to enable the operator to specify the material and dimensions of a collimator. This report details the progress made in simulating gamma-ray spectra for a variety of user-specified detector designs. In addition, a short discussion of work done in the related areas of pulse shape analysis and the spectral analysis is included. The pulse shape analysis and spectral analysis work is being performed pursuant to the requirements of contract F-94-C-0006, for the Advanced Research Projects Agency and the U.S. Air Force.

  20. Free Molecular Heat Transfer Programs for Setup and Dynamic Updating the Conductors in Thermal Desktop

    NASA Technical Reports Server (NTRS)

    Malroy, Eric T.

    2007-01-01

    The programs, arrays and logic structure were developed to enable the dynamic update of conductors in thermal desktop. The MatLab program FMHTPRE.m processes the Thermal Desktop conductors and sets up the arrays. The user needs to manually copy portions of the output to different input regions in Thermal Desktop. Also, Fortran subroutines are provided that perform the actual updates to the conductors. The subroutines are setup for helium gas, but the equations can be modified for other gases. The maximum number of free molecular conductors allowed is 10,000 for a given radiation task. Additional radiation tasks for FMHT can be generated to account for more conductors. Modifications to the Fortran subroutines may be warranted, when the mode of heat transfer is in the mixed or continuum mode. The FMHT Thermal Desktop model should be activated by using the "Case Set Manager" once the model is setup. Careful setup of the model is needed to avoid excessive solve times.

  1. ASTEP user's guide and software documentation

    NASA Technical Reports Server (NTRS)

    Gliniewicz, A. S.; Lachowski, H. M.; Pace, W. H., Jr.; Salvato, P., Jr.

    1974-01-01

    The Algorithm Simulation Test and Evaluation Program (ASTEP) is a modular computer program developed for the purpose of testing and evaluating methods of processing remotely sensed multispectral scanner earth resources data. ASTEP is written in FORTRAND V on the UNIVAC 1110 under the EXEC 8 operating system and may be operated in either a batch or interactive mode. The program currently contains over one hundred subroutines consisting of data classification and display algorithms, statistical analysis algorithms, utility support routines, and feature selection capability. The current program can accept data in LARSC1, LARSC2, ERTS, and Universal formats, and can output processed image or data tapes in Universal format.

  2. Beach Profile Analysis Systems (BPAS). Volume VI. BPAS User’s Guide: Analysis Module VOLCTR.

    DTIC Science & Technology

    1982-06-01

    the two seawardmost points. Before computing volume changes, common bonds are established relative to the landward and seaward extent of the surveys on...bit word size, the FORTRAN- callable sort routine (interfacing with the NOS or NOSME operating system SORTMRG utility), and the utility subroutines and

  3. Simplified plotting package for the LSI-11 computer and Tektronix terminals

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Henline, P.

    1980-12-01

    These plotting subroutines were written to allow the user to do plotting easily and quickly, but do not contain many fancy features in order to minimize memory space. Plots are produced of real values only. The first element of the plotting array contains the number of points to plot and the values to plot are stored in the remaining array locations. The maximum number of points which can be plotted is 300. The user must provide titles and other alpha numeric information. This can be done easily by a call to LOCATE, then ALPHA, and then doing a FORTRAN write.more » LOCATE and ALPHA are part of the Oak Ridge TEK11 Graphics Package. All plots are framed and labeled. The X axis has ten tick marks and three labels (left, center, and right side) and the Y axis has three tick marks and three labels. The subroutines assume the user is smart. Curves (especially when more than one is drawn on one plot) are assumed to be completely within the defined area as no clipping or dark lines are drawn. The user has the ability to do multiple curves on one graph or multiple graphs on a page.« less

  4. Recent Updates to the MELCOR 1.8.2 Code for ITER Applications

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Merrill, Brad J

    This report documents recent changes made to the MELCOR 1.8.2 computer code for application to the International Thermonuclear Experimental Reactor (ITER), as required by ITER Task Agreement ITA 81-18. There are four areas of change documented by this report. The first area is the addition to this code of a model for transporting HTO. The second area is the updating of the material oxidation correlations to match those specified in the ITER Safety Analysis Data List (SADL). The third area replaces a modification to an aerosol tranpsort subroutine that specified the nominal aerosol density internally with one that now allowsmore » the user to specify this density through user input. The fourth area corrected an error that existed in an air condensation subroutine of previous versions of this modified MELCOR code. The appendices of this report contain FORTRAN listings of the coding for these modifications.« less

  5. PETSc Users Manual Revision 3.3

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Balay, S.; Brown, J.; Buschelman, K.

    This manual describes the use of PETSc for the numerical solution of partial differential equations and related problems on high-performance computers. The Portable, Extensible Toolkit for Scientific Computation (PETSc) is a suite of data structures and routines that provide the building blocks for the implementation of large-scale application codes on parallel (and serial) computers. PETSc uses the MPI standard for all message-passing communication. PETSc includes an expanding suite of parallel linear, nonlinear equation solvers and time integrators that may be used in application codes written in Fortran, C, C++, Python, and MATLAB (sequential). PETSc provides many of the mechanisms neededmore » within parallel application codes, such as parallel matrix and vector assembly routines. The library is organized hierarchically, enabling users to employ the level of abstraction that is most appropriate for a particular problem. By using techniques of object-oriented programming, PETSc provides enormous flexibility for users. PETSc is a sophisticated set of software tools; as such, for some users it initially has a much steeper learning curve than a simple subroutine library. In particular, for individuals without some computer science background, experience programming in C, C++ or Fortran and experience using a debugger such as gdb or dbx, it may require a significant amount of time to take full advantage of the features that enable efficient software use. However, the power of the PETSc design and the algorithms it incorporates may make the efficient implementation of many application codes simpler than “rolling them” yourself; For many tasks a package such as MATLAB is often the best tool; PETSc is not intended for the classes of problems for which effective MATLAB code can be written. PETSc also has a MATLAB interface, so portions of your code can be written in MATLAB to “try out” the PETSc solvers. The resulting code will not be scalable however because

  6. PETSc Users Manual Revision 3.4

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Balay, S.; Brown, J.; Buschelman, K.

    This manual describes the use of PETSc for the numerical solution of partial differential equations and related problems on high-performance computers. The Portable, Extensible Toolkit for Scientific Computation (PETSc) is a suite of data structures and routines that provide the building blocks for the implementation of large-scale application codes on parallel (and serial) computers. PETSc uses the MPI standard for all message-passing communication. PETSc includes an expanding suite of parallel linear, nonlinear equation solvers and time integrators that may be used in application codes written in Fortran, C, C++, Python, and MATLAB (sequential). PETSc provides many of the mechanisms neededmore » within parallel application codes, such as parallel matrix and vector assembly routines. The library is organized hierarchically, enabling users to employ the level of abstraction that is most appropriate for a particular problem. By using techniques of object-oriented programming, PETSc provides enormous flexibility for users. PETSc is a sophisticated set of software tools; as such, for some users it initially has a much steeper learning curve than a simple subroutine library. In particular, for individuals without some computer science background, experience programming in C, C++ or Fortran and experience using a debugger such as gdb or dbx, it may require a significant amount of time to take full advantage of the features that enable efficient software use. However, the power of the PETSc design and the algorithms it incorporates may make the efficient implementation of many application codes simpler than “rolling them” yourself; For many tasks a package such as MATLAB is often the best tool; PETSc is not intended for the classes of problems for which effective MATLAB code can be written. PETSc also has a MATLAB interface, so portions of your code can be written in MATLAB to “try out” the PETSc solvers. The resulting code will not be scalable however because

  7. PETSc Users Manual Revision 3.5

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Balay, S.; Abhyankar, S.; Adams, M.

    This manual describes the use of PETSc for the numerical solution of partial differential equations and related problems on high-performance computers. The Portable, Extensible Toolkit for Scientific Computation (PETSc) is a suite of data structures and routines that provide the building blocks for the implementation of large-scale application codes on parallel (and serial) computers. PETSc uses the MPI standard for all message-passing communication. PETSc includes an expanding suite of parallel linear, nonlinear equation solvers and time integrators that may be used in application codes written in Fortran, C, C++, Python, and MATLAB (sequential). PETSc provides many of the mechanisms neededmore » within parallel application codes, such as parallel matrix and vector assembly routines. The library is organized hierarchically, enabling users to employ the level of abstraction that is most appropriate for a particular problem. By using techniques of object-oriented programming, PETSc provides enormous flexibility for users. PETSc is a sophisticated set of software tools; as such, for some users it initially has a much steeper learning curve than a simple subroutine library. In particular, for individuals without some computer science background, experience programming in C, C++ or Fortran and experience using a debugger such as gdb or dbx, it may require a significant amount of time to take full advantage of the features that enable efficient software use. However, the power of the PETSc design and the algorithms it incorporates may make the efficient implementation of many application codes simpler than “rolling them” yourself. ;For many tasks a package such as MATLAB is often the best tool; PETSc is not intended for the classes of problems for which effective MATLAB code can be written. PETSc also has a MATLAB interface, so portions of your code can be written in MATLAB to “try out” the PETSc solvers. The resulting code will not be scalable however because

  8. User Education Resources: USER.

    ERIC Educational Resources Information Center

    Condon, Patrick; Cook, Johanna

    This report describes User Education Resources (USER), an Australian database containing both print and audiovisual materials related to library instruction. Intended to make a wide range of ideas readily available to librarians interested in educating library patrons, USER collects catalog guides, classification guides, evaluation forms, floor…

  9. Hydrologic data-verification management program plan

    USGS Publications Warehouse

    Alexander, C.W.

    1982-01-01

    Data verification refers to the performance of quality control on hydrologic data that have been retrieved from the field and are being prepared for dissemination to water-data users. Water-data users now have access to computerized data files containing unpublished, unverified hydrologic data. Therefore, it is necessary to develop techniques and systems whereby the computer can perform some data-verification functions before the data are stored in user-accessible files. Computerized data-verification routines can be developed for this purpose. A single, unified concept describing master data-verification program using multiple special-purpose subroutines, and a screen file containing verification criteria, can probably be adapted to any type and size of computer-processing system. Some traditional manual-verification procedures can be adapted for computerized verification, but new procedures can also be developed that would take advantage of the powerful statistical tools and data-handling procedures available to the computer. Prototype data-verification systems should be developed for all three data-processing environments as soon as possible. The WATSTORE system probably affords the greatest opportunity for long-range research and testing of new verification subroutines. (USGS)

  10. Development of a stress-mode sensitive viscoelastic constitutive relationship for asphalt concrete: experimental and numerical modeling

    NASA Astrophysics Data System (ADS)

    Karimi, Mohammad M.; Tabatabaee, Nader; Jahanbakhsh, H.; Jahangiri, Behnam

    2017-08-01

    Asphalt binder is responsible for the thermo-viscoelastic mechanical behavior of asphalt concrete. Upon application of pure compressive stress to an asphalt concrete specimen, the stress is transferred by mechanisms such as aggregate interlock and the adhesion/cohesion properties of asphalt mastic. In the pure tensile stress mode, aggregate interlock plays a limited role in stress transfer, and the mastic phase plays the dominant role through its adhesive/cohesive and viscoelastic properties. Under actual combined loading patterns, any coordinate direction may experience different stress modes; therefore, the mechanical behavior is not the same in the different directions and the asphalt specimen behaves as an anisotropic material. The present study developed an anisotropic nonlinear viscoelastic constitutive relationship that is sensitive to the tension/compression stress mode by extending Schapery's nonlinear viscoelastic model. The proposed constitutive relationship was implemented in Abaqus using a user material (UMAT) subroutine in an implicit scheme. Uniaxial compression and indirect tension (IDT) testing were used to characterize the viscoelastic properties of the bituminous materials and to calibrate and validate the proposed constitutive relationship. Compressive and tensile creep compliances were calculated using uniaxial compression, as well as IDT test results, for different creep-recovery loading patterns at intermediate temperature. The results showed that both tensile creep compliance and its rate were greater than those of compression. The calculated deflections based on these IDT test simulations were compared with experimental measurements and were deemed acceptable. This suggests that the proposed viscoelastic constitutive relationship correctly demonstrates the viscoelastic response and is more accurate for analysis of asphalt concrete in the laboratory or in situ.

  11. Sensitivity of polycrystal plasticity to slip system kinematic hardening laws for Al 7075-T6

    DOE PAGES

    Hennessey, Conor; Castelluccio, Gustavo M.; McDowell, David L.

    2017-02-01

    The prediction of formation and early growth of microstructurally small fatigue cracks requires use of constitutive models that accurately estimate local states of stress, strain, and cyclic plastic strain. However, few research efforts have attempted to systematically consider the sensitivity of overall cyclic stress-strain hysteresis and higher order mean stress relaxation and plastic strain ratcheting responses introduced by the slip system back-stress formulation in crystal plasticity, even for face centered cubic (FCC) crystal systems. This paper explores the performance of two slip system level kinematic hardening models using a finite element crystal plasticity implementation as a User Material Subroutine (UMAT)more » within ABAQUS, with fully implicit numerical integration. The two kinematic hardening formulations aim to reproduce the cyclic deformation of polycrystalline Al 7075-T6 in terms of both macroscopic cyclic stress-strain hysteresis loop shape, as well as ratcheting and mean stress relaxation under strain- or stress-controlled loading with mean strain or stress, respectively. The first formulation is an Armstrong-Frederick type hardening-dynamic recovery law for evolution of the back stress. This approach is capable of reproducing observed deformation under completely reversed uniaxial loading conditions, but overpredicts the rate of cyclic ratcheting and associated mean stress relaxation. The second formulation corresponds to a multiple back stress Ohno-Wang type hardening law with nonlinear dynamic recovery. The adoption of this back stress evolution law greatly improves the capability to model experimental results for polycrystalline specimens subjected to cycling with mean stress or strain. As a result, the relation of such nonlinear dynamic recovery effects are related to slip system interactions with dislocation substructures.« less

  12. Sensitivity of polycrystal plasticity to slip system kinematic hardening laws for Al 7075-T6

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hennessey, Conor; Castelluccio, Gustavo M.; McDowell, David L.

    The prediction of formation and early growth of microstructurally small fatigue cracks requires use of constitutive models that accurately estimate local states of stress, strain, and cyclic plastic strain. However, few research efforts have attempted to systematically consider the sensitivity of overall cyclic stress-strain hysteresis and higher order mean stress relaxation and plastic strain ratcheting responses introduced by the slip system back-stress formulation in crystal plasticity, even for face centered cubic (FCC) crystal systems. This paper explores the performance of two slip system level kinematic hardening models using a finite element crystal plasticity implementation as a User Material Subroutine (UMAT)more » within ABAQUS, with fully implicit numerical integration. The two kinematic hardening formulations aim to reproduce the cyclic deformation of polycrystalline Al 7075-T6 in terms of both macroscopic cyclic stress-strain hysteresis loop shape, as well as ratcheting and mean stress relaxation under strain- or stress-controlled loading with mean strain or stress, respectively. The first formulation is an Armstrong-Frederick type hardening-dynamic recovery law for evolution of the back stress. This approach is capable of reproducing observed deformation under completely reversed uniaxial loading conditions, but overpredicts the rate of cyclic ratcheting and associated mean stress relaxation. The second formulation corresponds to a multiple back stress Ohno-Wang type hardening law with nonlinear dynamic recovery. The adoption of this back stress evolution law greatly improves the capability to model experimental results for polycrystalline specimens subjected to cycling with mean stress or strain. As a result, the relation of such nonlinear dynamic recovery effects are related to slip system interactions with dislocation substructures.« less

  13. On the mechanics of growing thin biological membranes

    PubMed Central

    Rausch, Manuel K.; Kuhl, Ellen

    2013-01-01

    Despite their seemingly delicate appearance, thin biological membranes fulfill various crucial roles in the human body and can sustain substantial mechanical loads. Unlike engineering structures, biological membranes are able to grow and adapt to changes in their mechanical environment. Finite element modeling of biological growth holds the potential to better understand the interplay of membrane form and function and to reliably predict the effects of disease or medical intervention. However, standard continuum elements typically fail to represent thin biological membranes efficiently, accurately, and robustly. Moreover, continuum models are typically cumbersome to generate from surface-based medical imaging data. Here we propose a computational model for finite membrane growth using a classical midsurface representation compatible with standard shell elements. By assuming elastic incompressibility and membrane-only growth, the model a priori satisfies the zero-normal stress condition. To demonstrate its modular nature, we implement the membrane growth model into the general-purpose non-linear finite element package Abaqus/Standard using the concept of user subroutines. To probe efficiently and robustness, we simulate selected benchmark examples of growing biological membranes under different loading conditions. To demonstrate the clinical potential, we simulate the functional adaptation of a heart valve leaflet in ischemic cardiomyopathy. We believe that our novel approach will be widely applicable to simulate the adaptive chronic growth of thin biological structures including skin membranes, mucous membranes, fetal membranes, tympanic membranes, corneoscleral membranes, and heart valve membranes. Ultimately, our model can be used to identify diseased states, predict disease evolution, and guide the design of interventional or pharmaceutic therapies to arrest or revert disease progression. PMID:24563551

  14. Modelling and simulation of cure in pultrusion processes

    NASA Astrophysics Data System (ADS)

    Tucci, F.; Rubino, F.; Paradiso, V.; Carlone, P.; Valente, R.

    2017-10-01

    Trial and error approach is not a suitable method to optimize the pultrusion process because of the high times required for the start up and the wide range of possible combinations of matrix and reinforcement. On the other hand, numerical approaches can be a suitable solution to test different parameter configuration. One of the main tasks in pultrusion processes is to obtain a complete and homogeneous resin polymerization. The formation of cross-links between polymeric chains is thermally induced but it leads to a strong exothermic heat generation, hence the thermal and the chemical phenomena are mutually affected. It requires that the two problems have to be modelled in coupled way. The mathematical model used in this work considers the composite as a lumped material, whose thermal and mechanical properties are evaluated as function of resin and fibers properties. The numerical pattern is based on a quasi-static approach in a three-dimensional Eulerian domain, which describes both thermal and chemical phenomena. The data obtained are used in a simplified C.H.I.L.E. (Cure Hardening Instantaneous Linear Elastic) model to compute the mechanical properties of the resin fraction in the pultruded. The two combined approaches allow to formulate a numerical model which takes into account the normal (no-penetration) and tangential (viscosity/friction) interactions between die and profile, the pulling force and the hydrostatic pressure of the liquid resin to evaluate the stress and strain fields induced by the process within the pultruded. The implementation of the numerical models has been carried out using the ABAQUS finite element suite, by means of several user subroutines (in Fortran language) which improve the basic software potentialities.

  15. Computer programs: Information retrieval and data analysis, a compilation

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The items presented in this compilation are divided into two sections. Section one treats of computer usage devoted to the retrieval of information that affords the user rapid entry into voluminous collections of data on a selective basis. Section two is a more generalized collection of computer options for the user who needs to take such data and reduce it to an analytical study within a specific discipline. These programs, routines, and subroutines should prove useful to users who do not have access to more sophisticated and expensive computer software.

  16. Stochastic-Strength-Based Damage Simulation Tool for Ceramic Matrix and Polymer Matrix Composite Structures

    NASA Technical Reports Server (NTRS)

    Nemeth, Noel N.; Bednarcyk, Brett A.; Pineda, Evan J.; Walton, Owen J.; Arnold, Steven M.

    2016-01-01

    Stochastic-based, discrete-event progressive damage simulations of ceramic-matrix composite and polymer matrix composite material structures have been enabled through the development of a unique multiscale modeling tool. This effort involves coupling three independently developed software programs: (1) the Micromechanics Analysis Code with Generalized Method of Cells (MAC/GMC), (2) the Ceramics Analysis and Reliability Evaluation of Structures Life Prediction Program (CARES/ Life), and (3) the Abaqus finite element analysis (FEA) program. MAC/GMC contributes multiscale modeling capabilities and micromechanics relations to determine stresses and deformations at the microscale of the composite material repeating unit cell (RUC). CARES/Life contributes statistical multiaxial failure criteria that can be applied to the individual brittle-material constituents of the RUC. Abaqus is used at the global scale to model the overall composite structure. An Abaqus user-defined material (UMAT) interface, referred to here as "FEAMAC/CARES," was developed that enables MAC/GMC and CARES/Life to operate seamlessly with the Abaqus FEA code. For each FEAMAC/CARES simulation trial, the stochastic nature of brittle material strength results in random, discrete damage events, which incrementally progress and lead to ultimate structural failure. This report describes the FEAMAC/CARES methodology and discusses examples that illustrate the performance of the tool. A comprehensive example problem, simulating the progressive damage of laminated ceramic matrix composites under various off-axis loading conditions and including a double notched tensile specimen geometry, is described in a separate report.

  17. Bifilar analysis users manual, volume 2

    NASA Technical Reports Server (NTRS)

    Cassarino, S. J.

    1980-01-01

    The digital computer program developed to study the vibration response of a coupled rotor/bifilar/airframe coupled system is described. The theoretical development of the rotor/airframe system equations of motion is provided. The fuselage and bifilar absorber equations of motion are discussed. The modular block approach used in the make-up of this computer program is described. The input data needed to run the rotor and bifilar absorber analyses is described. Sample output formats are presented and discussed. The results for four test cases, which use the major logic paths of the computer program, are presented. The overall program structure is discussed in detail. The FORTRAN subroutines are described in detail.

  18. Comparison of various contact algorithms for poroelastic tissues.

    PubMed

    Galbusera, Fabio; Bashkuev, Maxim; Wilke, Hans-Joachim; Shirazi-Adl, Aboulfazl; Schmidt, Hendrik

    2014-01-01

    Capabilities of the commercial finite element package ABAQUS in simulating frictionless contact between two saturated porous structures were evaluated and compared with those of an open source code, FEBio. In ABAQUS, both the default contact implementation and another algorithm based on an iterative approach requiring script programming were considered. Test simulations included a patch test of two cylindrical slabs in a gapless contact and confined compression conditions; a confined compression test of a porous cylindrical slab with a spherical porous indenter; and finally two unconfined compression tests of soft tissues mimicking diarthrodial joints. The patch test showed almost identical results for all algorithms. On the contrary, the confined and unconfined compression tests demonstrated large differences related to distinct physical and boundary conditions considered in each of the three contact algorithms investigated in this study. In general, contact with non-uniform gaps between fluid-filled porous structures could be effectively simulated with either ABAQUS or FEBio. The user should be aware of the parameter definitions, assumptions and limitations in each case, and take into consideration the physics and boundary conditions of the problem of interest when searching for the most appropriate model.

  19. Crew appliance computer program manual, volume 1

    NASA Technical Reports Server (NTRS)

    Russell, D. J.

    1975-01-01

    Trade studies of numerous appliance concepts for advanced spacecraft galley, personal hygiene, housekeeping, and other areas were made to determine which best satisfy the space shuttle orbiter and modular space station mission requirements. Analytical models of selected appliance concepts not currently included in the G-189A Generalized Environmental/Thermal Control and Life Support Systems (ETCLSS) Computer Program subroutine library were developed. The new appliance subroutines are given along with complete analytical model descriptions, solution methods, user's input instructions, and validation run results. The appliance components modeled were integrated with G-189A ETCLSS models for shuttle orbiter and modular space station, and results from computer runs of these systems are presented.

  20. Wheat stress indicator model, Crop Condition Assessment Division (CCAD) data base interface driver, user's manual

    NASA Technical Reports Server (NTRS)

    Hansen, R. F. (Principal Investigator)

    1981-01-01

    The use of the wheat stress indicator model CCAD data base interface driver is described. The purpose of this system is to interface the wheat stress indicator model with the CCAD operational data base. The interface driver routine decides what meteorological stations should be processed and calls the proper subroutines to process the stations.

  1. GASP - THERMODYNAMIC AND TRANSPORT PROPERTIES OF HELIUM, METHANE, NEON, NITROGEN, CARBON MONOXIDE, CARBON DIOXIDE, OXYGEN, AND ARGON

    NASA Technical Reports Server (NTRS)

    Hendricks, R. C.

    1994-01-01

    A computer program, GASP, has been written to calculate the thermodynamic and transport properties of argon, carbon dioxide, carbon monoxide, fluorine, methane, neon, nitrogen, and oxygen. GASP accepts any two of pressure, temperature, or density as input. In addition, entropy and enthalpy are possible inputs. Outputs are temperature, density, pressure, entropy, enthalpy, specific heats, expansion coefficient, sonic velocity, viscosity, thermal conductivity, and surface tension. A special technique is provided to estimate the thermal conductivity near the thermodynamic critical point. GASP is a group of FORTRAN subroutines. The user typically would write a main program that invoked GASP to provide only the described outputs. Subroutines are structured so that the user may call only those subroutines needed for his particular calculations. Allowable pressures range from 0.l atmosphere to 100 to l,000 atmospheres, depending on the fluid. Similarly, allowable pressures range from the triple point of each substance to 300 degrees K to 2000 degrees K, depending on the substance. The GASP package was developed to be used with heat transfer and fluid flow applications. It is particularly useful in applications of cryogenic fluids. Some problems associated with the liquefication, storage, and gasification of liquefied natural gas and liquefied petroleum gas can also be studied using GASP. This program is written in FORTRAN IV for batch execution and is available for implementation on IBM 7000 series computers. GASP was developed in 1971.

  2. Controlling Laboratory Processes From A Personal Computer

    NASA Technical Reports Server (NTRS)

    Will, H.; Mackin, M. A.

    1991-01-01

    Computer program provides natural-language process control from IBM PC or compatible computer. Sets up process-control system that either runs without operator or run by workers who have limited programming skills. Includes three smaller programs. Two of them, written in FORTRAN 77, record data and control research processes. Third program, written in Pascal, generates FORTRAN subroutines used by other two programs to identify user commands with device-driving routines written by user. Also includes set of input data allowing user to define user commands to be executed by computer. Requires personal computer operating under MS-DOS with suitable hardware interfaces to all controlled devices. Also requires FORTRAN 77 compiler and device drivers written by user.

  3. Users manual for the IMA program. Appendix C: Profile design program listing

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The source code for the Profile Design Program (PDP) for the Impulsive Mission Analysis (IMA) program is divided into several files. In a similar manner, the FORTRAN listings of the PDP's subroutines and function routines are organized into several groups in this appendix. Within each group, the FORTRAN listings are ordered alphabetically by routine name. Names and brief descriptions of each routine are listed in the same order as the Fortran listings.

  4. Code Usage Analysis System (CUAS)

    NASA Technical Reports Server (NTRS)

    Horsley, P. H.; Oliver, J. D.

    1976-01-01

    A set of computer programs is offered to aid a user in evaluating performance of an application program. The system provides reports of subroutine usage, program errors, and segment loading which occurred during the execution of an application program. It is presented in support of the development and validation of the space vehicle dynamics project.

  5. Interactive-graphic flowpath plotting for turbine engines

    NASA Technical Reports Server (NTRS)

    Corban, R. R.

    1981-01-01

    An engine cycle program capable of simulating the design and off-design performance of arbitrary turbine engines, and a computer code which, when used in conjunction with the cycle code, can predict the weight of the engines are described. A graphics subroutine was added to the code to enable the engineer to visualize the designed engine with more clarity by producing an overall view of the designed engine for output on a graphics device using IBM-370 graphics subroutines. In addition, with the engine drawn on a graphics screen, the program allows for the interactive user to make changes to the inputs to the code for the engine to be redrawn and reweighed. These improvements allow better use of the code in conjunction with the engine program.

  6. Analysis of high vacuum systems using SINDA'85

    NASA Technical Reports Server (NTRS)

    Spivey, R. A.; Clanton, S. E.; Moore, J. D.

    1993-01-01

    The theory, algorithms, and test data correlation analysis of a math model developed to predict performance of the Space Station Freedom Vacuum Exhaust System are presented. The theory used to predict the flow characteristics of viscous, transition, and molecular flow is presented in detail. Development of user subroutines which predict the flow characteristics in conjunction with the SINDA'85/FLUINT analysis software are discussed. The resistance-capacitance network approach with application to vacuum system analysis is demonstrated and results from the model are correlated with test data. The model was developed to predict the performance of the Space Station Freedom Vacuum Exhaust System. However, the unique use of the user subroutines developed in this model and written into the SINDA'85/FLUINT thermal analysis model provides a powerful tool that can be used to predict the transient performance of vacuum systems and gas flow in tubes of virtually any geometry. This can be accomplished using a resistance-capacitance (R-C) method very similar to the methods used to perform thermal analyses.

  7. The graphics and data acquisition software package

    NASA Technical Reports Server (NTRS)

    Crosier, W. G.

    1981-01-01

    A software package was developed for use with micro and minicomputers, particularly the LSI-11/DPD-11 series. The package has a number of Fortran-callable subroutines which perform a variety of frequently needed tasks for biomedical applications. All routines are well documented, flexible, easy to use and modify, and require minimal programmer knowledge of peripheral hardware. The package is also economical of memory and CPU time. A single subroutine call can perform any one of the following functions: (1) plot an array of integer values from sampled A/D data, (2) plot an array of Y values versus an array of X values; (3) draw horizontal and/or vertical grid lines of selectable type; (4) annotate grid lines with user units; (5) get coordinates of user controlled crosshairs from the terminal for interactive graphics; (6) sample any analog channel with program selectable gain; (7) wait a specified time interval, and (8) perform random access I/O of one or more blocks of a sequential disk file. Several miscellaneous functions are also provided.

  8. Mars Global Reference Atmospheric Model 2010 Version: Users Guide

    NASA Technical Reports Server (NTRS)

    Justh, H. L.

    2014-01-01

    This Technical Memorandum (TM) presents the Mars Global Reference Atmospheric Model 2010 (Mars-GRAM 2010) and its new features. Mars-GRAM is an engineering-level atmospheric model widely used for diverse mission applications. Applications include systems design, performance analysis, and operations planning for aerobraking, entry, descent and landing, and aerocapture. Additionally, this TM includes instructions on obtaining the Mars-GRAM source code and data files as well as running Mars-GRAM. It also contains sample Mars-GRAM input and output files and an example of how to incorporate Mars-GRAM as an atmospheric subroutine in a trajectory code.

  9. User interface user's guide for HYPGEN

    NASA Technical Reports Server (NTRS)

    Chiu, Ing-Tsau

    1992-01-01

    The user interface (UI) of HYPGEN is developed using Panel Library to shorten the learning curve for new users and provide easier ways to run HYPGEN for casual users as well as for advanced users. Menus, buttons, sliders, and type-in fields are used extensively in UI to allow users to point and click with a mouse to choose various available options or to change values of parameters. On-line help is provided to give users information on using UI without consulting the manual. Default values are set for most parameters and boundary conditions are determined by UI to further reduce the effort needed to run HYPGEN; however, users are free to make any changes and save it in a file for later use. A hook to PLOT3D is built in to allow graphics manipulation. The viewpoint and min/max box for PLOT3D windows are computed by UI and saved in a PLOT3D journal file. For large grids which take a long time to generate on workstations, the grid generator (HYPGEN) can be run on faster computers such as Crays, while UI stays at the workstation.

  10. MATH77, Version 4.0

    NASA Technical Reports Server (NTRS)

    Lawson, Charles L.; Krogh, Fred; Van Snyder, W.; Oken, Carol A.; Mccreary, Faith A.; Lieske, Jay H.; Perrine, Jack; Coffin, Ralph S.; Wayne, Warren J.

    1994-01-01

    MATH77 is high-quality library of ANSI FORTRAN 77 subprograms implementing contemporary algorithms for basic computational processes of science and engineering. Release 4.0 of MATH77 contains 454 user-callable and 136 lower-level subprograms. MATH77 release 4.0 subroutine library designed to be usable on any computer system supporting full ANSI standard FORTRAN 77 language.

  11. Computer program user's manual for FIREFINDER digital topographic data verification library dubbing system

    NASA Astrophysics Data System (ADS)

    Ceres, M.; Heselton, L. R., III

    1981-11-01

    This manual describes the computer programs for the FIREFINDER Digital Topographic Data Verification-Library-Dubbing System (FFDTDVLDS), and will assist in the maintenance of these programs. The manual contains detailed flow diagrams and associated descriptions for each computer program routine and subroutine. Complete computer program listings are also included. This information should be used when changes are made in the computer programs. The operating system has been designed to minimize operator intervention.

  12. Enabling User to User Interactions in Web Lectures with History-Aware User Awareness

    ERIC Educational Resources Information Center

    Ketterl, Markus; Mertens, Robert; Wiesen, Christoph; Vornberger, Oliver

    2011-01-01

    Purpose: The purpose of this paper is to present a user interface for web lectures for engaging with other users while working with video based learning content. The application allows its users to ask questions about the content and to get answers from those users that currently online are more familiar with it. The filtering is based on the…

  13. Transportable Applications Environment Plus, Version 5.1

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Transportable Applications Environment Plus (TAE+) computer program providing integrated, portable programming environment for developing and running application programs based on interactive windows, text, and graphical objects. Enables both programmers and nonprogrammers to construct own custom application interfaces easily and to move interfaces and application programs to different computers. Used to define corporate user interface, with noticeable improvements in application developer's and end user's learning curves. Main components are; WorkBench, What You See Is What You Get (WYSIWYG) software tool for design and layout of user interface; and WPT (Window Programming Tools) Package, set of callable subroutines controlling user interface of application program. WorkBench and WPT's written in C++, and remaining code written in C.

  14. On the relevance of modeling viscoelastic bending behavior in finite element forming simulation of continuously fiber reinforced thermoplastics

    NASA Astrophysics Data System (ADS)

    Dörr, Dominik; Schirmaier, Fabian J.; Henning, Frank; Kärger, Luise

    2017-10-01

    Finite Element (FE) forming simulation offers the possibility of a detailed analysis of the deformation behavior of multilayered thermoplastic blanks during forming, considering material behavior and process conditions. Rate-dependent bending behavior is a material characteristic, which is so far not considered in FE forming simulation of pre-impregnated, continuously fiber reinforced polymers (CFRPs). Therefore, an approach for modeling viscoelastic bending behavior in FE composite forming simulation is presented in this work. The presented approach accounts for the distinct rate-dependent bending behavior of e.g. thermoplastic CFRPs at process conditions. The approach is based on a Voigt-Kelvin (VK) and a generalized Maxwell (GM) approach, implemented within a FE forming simulation framework implemented in several user-subroutines of the commercially available FE solver Abaqus. The VK, GM, as well as purely elastic bending modeling approaches are parameterized according to dynamic bending characterization results for a PA6-CF UD-tape. It is found that only the GM approach is capable to represent the bending deformation characteristic for all of the considered bending deformation rates. The parameterized bending modeling approaches are applied to a hemisphere test and to a generic geometry. A comparison of the forming simulation results of the generic geometry to experimental tests show a good agreement between simulation and experiments. Furthermore, the simulation results reveal that especially a correct modeling of the initial bending stiffness is relevant for the prediction of wrinkling behavior, as a similar onset of wrinkles is observed for the GM, the VK and an elastic approach, fitted to the stiffness observed in the dynamic rheometer test for low curvatures. Hence, characterization and modeling of rate-dependent bending behavior is crucial for FE forming simulation of thermoplastic CFRPs.

  15. An experimental and computational investigation of dynamic ductile fracture in stainless steel welds

    NASA Astrophysics Data System (ADS)

    Kothnur, Vasanth Srinivasa

    The high strain rate viscoplastic flow and fracture behavior of NITRONIC-50 and AL6XN stainless steel weldments are studied under dynamic loading conditions. The study is primarily motivated by interest in modeling the micromechanics of dynamic ductile failure in heterogeneous weldments. The high strain rate response of specimens machined from the parent, weld and heat-affected zones of NITRONIC-50 and AL6XN weldments is reported here on the basis of experiments conducted in a compression Kolsky bar configuration. The failure response of specimens prepared from the various material zones is investigated under high rate loading conditions in a tension Kolsky bar set-up. The microstructure of voided fracture process zones in these weldments is studied using X-ray Computed Microtomography. To model the preferential evolution of damage near the heat-affected zone, a finite deformation elastic-viscoplastic constitutive model for porous materials is developed. The evolution of the macroscopic flow response and the porous microstructure have been analysed in two distinctive regimes: pre-coalescence and post-coalescence. The onset of void coalescence is analyzed on the basis of upper-bound models to obtain the limit-loads needed to sustain a localized mode of plastic flow in the inter-void ligament. A finite element framework for the integration of the porous material response under high rate loading conditions is implemented as a user-subroutine in ABAQUS/Explicit. To address the effect of mesh sensitivity of numerical simulations of ductile fracture, a microstructural length scale is used to discretize finite element models of test specimens. Results from a detailed finite element study of the deformation and damage evolution in AL6XN weldments are compared with experimental observations.

  16. On Complexities of Impact Simulation of Fiber Reinforced Polymer Composites: A Simplified Modeling Framework

    PubMed Central

    Alemi-Ardakani, M.; Milani, A. S.; Yannacopoulos, S.

    2014-01-01

    Impact modeling of fiber reinforced polymer composites is a complex and challenging task, in particular for practitioners with less experience in advanced coding and user-defined subroutines. Different numerical algorithms have been developed over the past decades for impact modeling of composites, yet a considerable gap often exists between predicted and experimental observations. In this paper, after a review of reported sources of complexities in impact modeling of fiber reinforced polymer composites, two simplified approaches are presented for fast simulation of out-of-plane impact response of these materials considering four main effects: (a) strain rate dependency of the mechanical properties, (b) difference between tensile and flexural bending responses, (c) delamination, and (d) the geometry of fixture (clamping conditions). In the first approach, it is shown that by applying correction factors to the quasistatic material properties, which are often readily available from material datasheets, the role of these four sources in modeling impact response of a given composite may be accounted for. As a result a rough estimation of the dynamic force response of the composite can be attained. To show the application of the approach, a twill woven polypropylene/glass reinforced thermoplastic composite laminate has been tested under 200 J impact energy and was modeled in Abaqus/Explicit via the built-in Hashin damage criteria. X-ray microtomography was used to investigate the presence of delamination inside the impacted sample. Finally, as a second and much simpler modeling approach it is shown that applying only a single correction factor over all material properties at once can still yield a reasonable prediction. Both advantages and limitations of the simplified modeling framework are addressed in the performed case study. PMID:25431787

  17. Viscoelastic finite element analysis of residual stresses in porcelain-veneered zirconia dental crowns.

    PubMed

    Kim, Jeongho; Dhital, Sukirti; Zhivago, Paul; Kaizer, Marina R; Zhang, Yu

    2018-06-01

    The main problem of porcelain-veneered zirconia (PVZ) dental restorations is chipping and delamination of veneering porcelain owing to the development of deleterious residual stresses during the cooling phase of veneer firing. The aim of this study is to elucidate the effects of cooling rate, thermal contraction coefficient and elastic modulus on residual stresses developed in PVZ dental crowns using viscoelastic finite element methods (VFEM). A three-dimensional VFEM model has been developed to predict residual stresses in PVZ structures using ABAQUS finite element software and user subroutines. First, the newly established model was validated with experimentally measured residual stress profiles using Vickers indentation on flat PVZ specimens. An excellent agreement between the model prediction and experimental data was found. Then, the model was used to predict residual stresses in more complex anatomically-correct crown systems. Two PVZ crown systems with different thermal contraction coefficients and porcelain moduli were studied: VM9/Y-TZP and LAVA/Y-TZP. A sequential dual-step finite element analysis was performed: heat transfer analysis and viscoelastic stress analysis. Controlled and bench convection cooling rates were simulated by applying different convective heat transfer coefficients 1.7E-5 W/mm 2 °C (controlled cooling) and 0.6E-4 W/mm 2 °C (bench cooling) on the crown surfaces exposed to the air. Rigorous viscoelastic finite element analysis revealed that controlled cooling results in lower maximum stresses in both veneer and core layers for the two PVZ systems relative to bench cooling. Better compatibility of thermal contraction coefficients between porcelain and zirconia and a lower porcelain modulus reduce residual stresses in both layers. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. A Computer Code for Dynamic Stress Analysis of Media-Structure Problems with Nonlinearities (SAMSON). Volume III. User’s Manual.

    DTIC Science & Technology

    NONLINEAR SYSTEMS, LINEAR SYSTEMS, SUBROUTINES , SOIL MECHANICS, INTERFACES, DYNAMICS, LOADS(FORCES), FORCE(MECHANICS), DAMPING, ACCELERATION, ELASTIC...PROPERTIES, PLASTIC PROPERTIES, CRACKS , REINFORCING MATERIALS , COMPOSITE MATERIALS , FAILURE(MECHANICS), MECHANICAL PROPERTIES, INSTRUCTION MANUALS, DIGITAL COMPUTERS...STRESSES, *COMPUTER PROGRAMS), (*STRUCTURES, STRESSES), (*DATA PROCESSING, STRUCTURAL PROPERTIES), SOILS , STRAIN(MECHANICS), MATHEMATICAL MODELS

  19. Verbal learning and memory in adolescent cannabis users, alcohol users and non-users.

    PubMed

    Solowij, Nadia; Jones, Katy A; Rozman, Megan E; Davis, Sasha M; Ciarrochi, Joseph; Heaven, Patrick C L; Lubman, Dan I; Yücel, Murat

    2011-07-01

    Long-term heavy cannabis use can result in memory impairment. Adolescent users may be especially vulnerable to the adverse neurocognitive effects of cannabis. In a cross-sectional and prospective neuropsychological study of 181 adolescents aged 16-20 (mean 18.3 years), we compared performance indices from one of the most widely used measures of learning and memory--the Rey Auditory Verbal Learning Test--between cannabis users (n=52; mean 2.4 years of use, 14 days/month, median abstinence 20.3 h), alcohol users (n=67) and non-user controls (n=62) matched for age, education and premorbid intellectual ability (assessed prospectively), and alcohol consumption for cannabis and alcohol users. Cannabis users performed significantly worse than alcohol users and non-users on all performance indices. They recalled significantly fewer words overall (p<0.001), demonstrating impaired learning (p<0.001), retention (p<0.001) and retrieval (p<0.05) (Cohen's d 0.43-0.84). The degree of impairment was associated with the duration, quantity, frequency and age of onset of cannabis use, but was unrelated to alcohol exposure or other drug use. No gender effects were detected and the findings remained after controlling for premorbid intellectual ability. An earlier age of onset of regular cannabis use was associated with worse memory performance after controlling for extent of exposure to cannabis. Despite relatively brief exposure, adolescent cannabis users relative to their age-matched counterparts demonstrated similar memory deficits to those reported in adult long-term heavy users. The results indicate that cannabis adversely affects the developing brain and reinforce concerns regarding the impact of early exposure.

  20. Space Trajectories Error Analysis (STEAP) Programs. Volume 1: Analytic manual, update

    NASA Technical Reports Server (NTRS)

    1971-01-01

    Manual revisions are presented for the modified and expanded STEAP series. The STEAP 2 is composed of three independent but related programs: NOMAL for the generation of n-body nominal trajectories performing a number of deterministic guidance events; ERRAN for the linear error analysis and generalized covariance analysis along specific targeted trajectories; and SIMUL for testing the mathematical models used in the navigation and guidance process. The analytic manual provides general problem description, formulation, and solution and the detailed analysis of subroutines. The programmers' manual gives descriptions of the overall structure of the programs as well as the computational flow and analysis of the individual subroutines. The user's manual provides information on the input and output quantities of the programs. These are updates to N69-36472 and N69-36473.

  1. An object-oriented data reduction system in Fortran

    NASA Technical Reports Server (NTRS)

    Bailey, J.

    1992-01-01

    A data reduction system for the AAO two-degree field project is being developed using an object-oriented approach. Rather than use an object-oriented language (such as C++) the system is written in Fortran and makes extensive use of existing subroutine libraries provided by the UK Starlink project. Objects are created using the extensible N-dimensional Data Format (NDF) which itself is based on the Hierarchical Data System (HDS). The software consists of a class library, with each class corresponding to a Fortran subroutine with a standard calling sequence. The methods of the classes provide operations on NDF objects at a similar level of functionality to the applications of conventional data reduction systems. However, because they are provided as callable subroutines, they can be used as building blocks for more specialist applications. The class library is not dependent on a particular software environment thought it can be used effectively in ADAM applications. It can also be used from standalone Fortran programs. It is intended to develop a graphical user interface for use with the class library to form the 2dF data reduction system.

  2. Energy Based Multiscale Modeling with Non-Periodic Boundary Conditions

    DTIC Science & Technology

    2013-05-13

    below in Figure 8. At each incremental step in the analysis , the user material defined subroutine (UMAT) was utilized to perform the communication...initiation and modeling using XFEM. Appropriate localization schemes will be developed to allow for deformations conducive for crack opening...REFERENCES 1. Talreja R., 2006, “Damage analysis for structural integrity and durability of composite materials ,” Fatigue & Fracture of

  3. METal matrix composite ANalyzer (METCAN): Theoretical manual

    NASA Technical Reports Server (NTRS)

    Murthy, P. L. N.; Chamis, C. C.

    1993-01-01

    This manuscript is intended to be a companion volume to the 'METCAN User's Manual' and the 'METAN Demonstration Manual.' The primary purpose of the manual is to give details pertaining to micromechanics and macromechanics equations of high temperature metal matrix composites that are programmed in the METCAN computer code. The subroutines which contain the programmed equations are also mentioned in order to facilitate any future changes or modifications that the user may intend to incorporate in the code. Assumptions and derivations leading to the micromechanics equations are briefly mentioned.

  4. Identifying online user reputation in terms of user preference

    NASA Astrophysics Data System (ADS)

    Dai, Lu; Guo, Qiang; Liu, Xiao-Lu; Liu, Jian-Guo; Zhang, Yi-Cheng

    2018-03-01

    Identifying online user reputation is significant for online social systems. In this paper, taking into account the preference physics of online user collective behaviors, we present an improved group-based rating method for ranking online user reputation based on the user preference (PGR). All the ratings given by each specific user are mapped to the same rating criteria. By grouping users according to their mapped ratings, the online user reputation is calculated based on the corresponding group sizes. Results for MovieLens and Netflix data sets show that the AUC values of the PGR method can reach 0.9842 (0.9493) and 0.9995 (0.9987) for malicious (random) spammers, respectively, outperforming the results generated by the traditional group-based method, which indicates that the online preference plays an important role for measuring user reputation.

  5. Axisymmetric whole pin life modelling of advanced gas-cooled reactor nuclear fuel

    NASA Astrophysics Data System (ADS)

    Mella, R.; Wenman, M. R.

    2013-06-01

    Thermo-mechanical contributions to pellet-clad interaction (PCI) in advanced gas-cooled reactors (AGRs) are modelled in the ABAQUS finite element (FE) code. User supplied sub-routines permit the modelling of the non-linear behaviour of AGR fuel through life. Through utilisation of ABAQUS's well-developed pre- and post-processing ability, the behaviour of the axially constrained steel clad fuel was modelled. The 2D axisymmetric model includes thermo-mechanical behaviour of the fuel with time and condition dependent material properties. Pellet cladding gap dynamics and thermal behaviour are also modelled. The model treats heat up as a fully coupled temperature-displacement study. Dwell time and direct power cycling was applied to model the impact of online refuelling, a key feature of the AGR. The model includes the visco-plastic behaviour of the fuel under the stress and irradiation conditions within an AGR core and a non-linear heat transfer model. A multiscale fission gas release model is applied to compute pin pressure; this model is coupled to the PCI gap model through an explicit fission gas inventory code. Whole pin, whole life, models are able to show the impact of the fuel on all segments of cladding including weld end caps and cladding pellet locking mechanisms (unique to AGR fuel). The development of this model in a commercial FE package shows that the development of a potentially verified and future-proof fuel performance code can be created and used. The usability of a FE based fuel performance code would be an enhancement over past codes. Pre- and post-processors have lowered the entry barrier for the development of a fuel performance model to permit the ability to model complicated systems. Typical runtimes for a 5 year axisymmetric model takes less than one hour on a single core workstation. The current model has implemented: Non-linear fuel thermal behaviour, including a complex description of heat flow in the fuel. Coupled with a variety of

  6. Decision Analysis for Remediation Technologies (DART) user`s manual

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sebo, D.

    1997-09-01

    This user`s manual is an introduction to the use of the Decision Analysis for Remediation Technology (DART) Report Generator. DART provides a user interface to a database containing site data (e.g., contaminants, waste depth, area) for sites within the Subsurface Contaminant Focus Area (SCFA). The database also contains SCFA requirements, needs, and technology information. The manual is arranged in two major sections. The first section describes loading DART onto a user system. The second section describes DART operation. DART operation is organized into sections by the user interface forms. For each form, user input, both optional and required, DART capabilities,more » and the result of user selections will be covered in sufficient detail to enable the user to understand DART, capabilities and determine how to use DART to meet specific needs.« less

  7. Chewing as a forming application: A viscoplastic damage law in modelling food oral breakdown

    NASA Astrophysics Data System (ADS)

    Skamniotis, C. G.; Charalambides, M. N.; Elliott, M.

    2017-10-01

    The first bite mechanical response of a food item resembles compressive forming processes, where a tool is pressed into a workpiece. The present study addresses ongoing interests in the deformations and damage of food products, particularly during the first bite, in relation to their mechanical properties. Uniaxial tension, compression and shear tests on a starch based food reveal stress-strain response and fracture strains strongly dependent on strain rate and stress triaxiality, while damage mechanisms are identified in the form of stress softening. A pressure dependent viscoplastic constitutive law reproduces the behavior with the aid of ABAQUS subroutines, while a ductile damage initiation and evolution framework based on fracture toughness data enables accurate predictions of the product breakdown. The material model is implemented in a Finite Element (FE) chewing model based on digital pet teeth geometry where the first bite of molar teeth against a food item is simulated. The FE force displacement results match the experimental data obtained by a physical replicate of the bite model, lending weight to the approach as a powerful tool in understanding of food breakdown and product development.

  8. Multi-Scale Ballistic Material Modeling of Cross-Plied Compliant Composites

    DTIC Science & Technology

    2009-01-01

    PERFORMING ORGANIZATION REPORT NUMBER 19a. NAME OF RESPONSIBLE PERSON 19b. TELEPHONE NUMBER Mica Grujicic 864-656-5639 3. DATES COVERED (From - To...Autodyn [ANSYS/Autodyn version 11.0, User Documentation, Century Dynamics Inc. a subsidiary of ANSYS Inc. (2007)] and ABA- QUS /Explicit [ABAQUS...matrix, Fig. 3(b). Bonding between the matrix and the filaments is represented using 7056 ‘‘cohesive” elements, (ABA- QUS /Explicit designation COH3D6

  9. User manual for Streamtube Curvature Analysis: Analytical method for predicting the pressure distribution about a nacelle at transonic speeds, appendix

    NASA Technical Reports Server (NTRS)

    Keith, J. S.; Ferguson, D. R.; Heck, P. H.

    1973-01-01

    The computer program listing of Streamtube Curvature Analysis is presented. The listing includes explanatory statements and titles so that the program flow is readily discernable. The computer program listing is in CDC FORTRAN 2.3 source language form, except for three subroutines, GETIX, GETRLX, and SAVIX, which are in COMPOSE 1.1 language.

  10. Automated Engineering Design (AED); An approach to automated documentation

    NASA Technical Reports Server (NTRS)

    Mcclure, C. W.

    1970-01-01

    The automated engineering design (AED) is reviewed, consisting of a high level systems programming language, a series of modular precoded subroutines, and a set of powerful software machine tools that effectively automate the production and design of new languages. AED is used primarily for development of problem and user-oriented languages. Software production phases are diagramed, and factors which inhibit effective documentation are evaluated.

  11. Computer program documentation modified version of the JA70 aerodynamic heating computer program H800 (MINIVER with a DISSPLA plot package

    NASA Technical Reports Server (NTRS)

    Olmedo, L.

    1980-01-01

    The changes, modifications, and inclusions which were adapted to the current version of the MINIVER program are discussed. Extensive modifications were made to various subroutines, and a new plot package added. This plot package is the Johnson Space Center DISSPLA Graphics System currently driven under an 1110 EXEC 8 configuration. User instructions on executing the MINIVER program are provided and the plot package is described.

  12. A computational system for aerodynamic design and analysis of supersonic aircraft. Part 1: General description and theoretical development

    NASA Technical Reports Server (NTRS)

    Middleton, W. D.; Lundry, J. L.

    1976-01-01

    An integrated system of computer programs was developed for the design and analysis of supersonic configurations. The system uses linearized theory methods for the calculation of surface pressures and supersonic area rule concepts in combination with linearized theory for calculation of aerodynamic force coefficients. Interactive graphics are optional at the user's request. Schematics of the program structure and the individual overlays and subroutines are described.

  13. Effects of Subscale Size and Shape on Global Energy Dissipation in a Multiscale Model of a Fiber-Reinforced Composite Exhibiting Post-Peak Strain Softening Using Abaqus and FEAMAC

    NASA Technical Reports Server (NTRS)

    Pineda, Evan, J.; Bednarcyk, Brett, A.; Arnold, Steven, M.

    2012-01-01

    A mesh objective crack band model is implemented in the generalized method of cells (GMC) micromechanics model to predict failure of a composite repeating unit cell (RUC). The micromechanics calculations are achieved using the MAC/GMC core engine within the ImMAC suite of micromechanics codes, developed at the NASA Glenn Research Center. The microscale RUC is linked to a macroscale Abaqus/Standard finite element model using the FEAMAC multiscale framework (included in the ImMAC suite). The effects of the relationship between the characteristic length of the finite element and the size of the microscale RUC on the total energy dissipation of the multiscale model are investigated. A simple 2-D composite square subjected to uniaxial tension is used to demonstrate the effects of scaling the dimensions of the RUC such that the length of the sides of the RUC are equal to the characteristic length of the finite element. These results are compared to simulations where the size of the RUC is fixed, independent of the element size. Simulations are carried out for a variety of mesh densities and element shapes, including square and triangular. Results indicate that a consistent size and shape must be used to yield preserve energy dissipation across the scales.

  14. Peak experiences of psilocybin users and non-users.

    PubMed

    Cummins, Christina; Lyke, Jennifer

    2013-01-01

    Maslow (1970) defined peak experiences as the most wonderful experiences of a person's life, which may include a sense of awe, well-being, or transcendence. Furthermore, recent research has suggested that psilocybin can produce experiences subjectively rated as uniquely meaningful and significant (Griffiths et al. 2006). It is therefore possible that psilocybin may facilitate or change the nature of peak experiences in users compared to non-users. This study was designed to compare the peak experiences of psilocybin users and non-users, to evaluate the frequency of peak experiences while under the influence of psilocybin, and to assess the perceived degree of alteration of consciousness during these experiences. Participants were recruited through convenience and snowball sampling from undergraduate classes and at a musical event. Participants were divided into three groups, those who reported a peak experience while under the influence of psilocybin (psilocybin peak experience: PPE), participants who had used psilocybin but reported their peak experiences did not occur while they were under the influence of psilocybin (non-psilocybin peak experience: NPPE), and participants who had never used psilocybin (non-user: NU). A total of 101 participants were asked to think about their peak experiences and complete a measure evaluating the degree of alteration of consciousness during that experience. Results indicated that 47% of psilocybin users reported their peak experience occurred while using psilocybin. In addition, there were significant differences among the three groups on all dimensions of alteration of consciousness. Future research is necessary to identify factors that influence the peak experiences of psilocybin users in naturalistic settings and contribute to the different characteristics of peak experiences of psilocybin users and non-users.

  15. Development of the FITS tools package for multiple software environments

    NASA Technical Reports Server (NTRS)

    Pence, W. D.; Blackburn, J. K.

    1992-01-01

    The HEASARC is developing a package of general purpose software for analyzing data files in FITS format. This paper describes the design philosophy which makes the software both machine-independent (it runs on VAXs, Suns, and DEC-stations) and software environment-independent. Currently the software can be compiled and linked to produce IRAF tasks, or alternatively, the same source code can be used to generate stand-alone tasks using one of two implementations of a user-parameter interface library. The machine independence of the software is achieved by writing the source code in ANSI standard Fortran or C, using the machine-independent FITSIO subroutine interface for all data file I/O, and using a standard user-parameter subroutine interface for all user I/O. The latter interface is based on the Fortran IRAF Parameter File interface developed at STScI. The IRAF tasks are built by linking to the IRAF implementation of this parameter interface library. Two other implementations of this parameter interface library, which have no IRAF dependencies, are now available which can be used to generate stand-alone executable tasks. These stand-alone tasks can simply be executed from the machine operating system prompt either by supplying all the task parameters on the command line or by entering the task name after which the user will be prompted for any required parameters. A first release of this FTOOLS package is now publicly available. The currently available tasks are described, along with instructions on how to obtain a copy of the software.

  16. E-cigarette Dual Users, Exclusive Users and Perceptions of Tobacco Products.

    PubMed

    Cooper, Maria; Case, Kathleen R; Loukas, Alexandra; Creamer, Melisa R; Perry, Cheryl L

    2016-01-01

    We examined differences in the characteristics of youth non-users, cigarette-only, e-cigarette-only, and dual e-cigarette and cigarette users. Using weighted, representative data, logistic regression analyses were conducted to examine differences in demographic characteristics and tobacco use behaviors across tobacco usage groups. Multiple linear regression analyses were conducted to examine differences in harm perceptions of various tobacco products and perceived peer use of e-cigarettes by tobacco usage group. Compared to non-users, dual users were more likely to be white, male, and high school students. Dual users had significantly higher prevalence of current use of all products (except hookah) than e-cigarette-only users, and higher prevalence of current use of snus and hookah than the cigarette-only group. Dual users had significantly lower harm perceptions for all tobacco products except for e-cigarettes and hookah as compared to e-cigarette-only users. Dual users reported higher peer use of cigarettes as compared to both exclusive user groups. Findings highlight dual users' higher prevalence of use of most other tobacco products, their lower harm perceptions of most tobacco products compared to e-cigarette-only users, and their higher perceived peer use of cigarettes compared to exclusive users.

  17. CARE 3 user-friendly interface user's guide

    NASA Technical Reports Server (NTRS)

    Martensen, A. L.

    1987-01-01

    CARE 3 predicts the unreliability of highly reliable reconfigurable fault-tolerant systems that include redundant computers or computer systems. CARE3MENU is a user-friendly interface used to create an input for the CARE 3 program. The CARE3MENU interface has been designed to minimize user input errors. Although a CARE3MENU session may be successfully completed and all parameters may be within specified limits or ranges, the CARE 3 program is not guaranteed to produce meaningful results if the user incorrectly interprets the CARE 3 stochastic model. The CARE3MENU User Guide provides complete information on how to create a CARE 3 model with the interface. The CARE3MENU interface runs under the VAX/VMS operating system.

  18. Stress Field Evolution in a Ball Bearing Raceway Fatigue Spall (PREPRINT)

    DTIC Science & Technology

    2009-10-01

    M50 steel V-Ring raceways, and extended the bearing life prediction methods of Ioannides and Harris (10) to predict the remaining useful life of...Carpenter VIM VAR M50 Bearing Steel ” (17) ABAQUS v6.8.2 Users Manual (18) Suresh, S., Fatigue of Materials. Second Edition, 2004, Cambridge University...images of spall’s edge cracks Figure 5. Finite Element Model Geometry Figure 6. a. Tracings of spall edges from M50 and Pyrowear 675 bearing steels

  19. The focal plane reception pattern calculation for a paraboloidal antenna with a nearby fence

    NASA Technical Reports Server (NTRS)

    Schmidt, Richard F.; Cheng, Hwai-Soon; Kao, Michael W.

    1987-01-01

    A computer simulation program is described which is used to estimate the effects of a proximate diffraction fence on the performance of paraboloid antennas. The computer program is written in FORTRAN. The physical problem, mathematical formulation and coordinate references are described. The main control structure of the program and the function of the individual subroutines are discussed. The Job Control Language set-up and program instruction are provided in the user's instruction to help users execute the present program. A sample problem with an appropriate output listing is made available as an illustration of the usage of the program.

  20. A FORTRAN program for the analysis of linear continuous and sample-data systems

    NASA Technical Reports Server (NTRS)

    Edwards, J. W.

    1976-01-01

    A FORTRAN digital computer program which performs the general analysis of linearized control systems is described. State variable techniques are used to analyze continuous, discrete, and sampled data systems. Analysis options include the calculation of system eigenvalues, transfer functions, root loci, root contours, frequency responses, power spectra, and transient responses for open- and closed-loop systems. A flexible data input format allows the user to define systems in a variety of representations. Data may be entered by inputing explicit data matrices or matrices constructed in user written subroutines, by specifying transfer function block diagrams, or by using a combination of these methods.

  1. Identifying online user reputation of user-object bipartite networks

    NASA Astrophysics Data System (ADS)

    Liu, Xiao-Lu; Liu, Jian-Guo; Yang, Kai; Guo, Qiang; Han, Jing-Ti

    2017-02-01

    Identifying online user reputation based on the rating information of the user-object bipartite networks is important for understanding online user collective behaviors. Based on the Bayesian analysis, we present a parameter-free algorithm for ranking online user reputation, where the user reputation is calculated based on the probability that their ratings are consistent with the main part of all user opinions. The experimental results show that the AUC values of the presented algorithm could reach 0.8929 and 0.8483 for the MovieLens and Netflix data sets, respectively, which is better than the results generated by the CR and IARR methods. Furthermore, the experimental results for different user groups indicate that the presented algorithm outperforms the iterative ranking methods in both ranking accuracy and computation complexity. Moreover, the results for the synthetic networks show that the computation complexity of the presented algorithm is a linear function of the network size, which suggests that the presented algorithm is very effective and efficient for the large scale dynamic online systems.

  2. E-cigarette Dual Users, Exclusive Users and Perceptions of Tobacco Products

    PubMed Central

    Cooper, Maria; Case, Kathleen R.; Loukas, Alexandra; Creamer, MeLisa R.; Perry, Cheryl L.

    2016-01-01

    Objectives We examined differences in the characteristics of youth non-users, cigarette-only, e-cigarette-only, and dual e-cigarette and cigarette users. Methods Using weighted, representative data, logistic regression analyses were conducted to examine differences in demographic characteristics and tobacco use behaviors across tobacco usage groups. Multiple linear regression analyses were conducted to examine differences in harm perceptions of various tobacco products and perceived peer use of e-cigarettes by tobacco usage group. Results Compared to non-users, dual users were more likely to be white, male, and high school students. Dual users had significantly higher prevalence of current use of all products (except hookah) than e-cigarette-only users, and higher prevalence of current use of snus and hookah than the cigarette-only group. Dual users had significantly lower harm perceptions for all tobacco products except for e-cigarettes and hookah as compared to e-cigarette-only users. Dual users reported higher peer use of cigarettes as compared to both exclusive user groups. Conclusion Findings highlight dual users’ higher prevalence of use of most other tobacco products, their lower harm perceptions of most tobacco products compared to e-cigarette-only users, and their higher perceived peer use of cigarettes compared to exclusive users. PMID:26685819

  3. Evaluating User Participation and User Influence in an Enterprise System

    ERIC Educational Resources Information Center

    Gibbs, Martin D.

    2010-01-01

    Does user influence have an impact on the data quality of an information systems development project? What decision making should users have? How can users effectively be engaged in the process? What is success? User participation is considered to be a critical success factor for Enterprise Resource Planning (ERP) projects, yet there is little…

  4. Understanding Active and Passive Users: The Effects of an Active User Using Normal, Hard and Unreliable Technologies on User Assessment of Trust in Technology and Co-User

    PubMed Central

    Montague, Enid; JieXu

    2011-01-01

    The aim of this study was to understand how passive users perceive the trustworthiness of active users and technologies under varying technological conditions. An experimental study was designed to vary the functioning of technologies that active users interacted with, while passive users observed these interactions. Active and passive user ratings of technology and partner were collected. Exploratory data analysis suggests that passive users developed perceptions of technologies based on the functioning of the technology and how the active user interacted with the technologies. Findings from this research have implications for the design of technologies in environments where active and passive users interact with technologies in different ways. Future work in this area should explore interventions that lead to enhanced affective engagement and trust calibration. PMID:22192788

  5. Institute for Defense Analysis. Annual Report 1993.

    DTIC Science & Technology

    1993-01-01

    model of computation on the user . One significant advantage of this approach is that AC is used effectively to program high performance subroutines ...capability to perform focused radar imaging through random media (tree canopies and soil , for example) and its capability to over- come heavy... Materials The ability to produce advanced materials at low cost is critical to the performance and affordability of future defense systems. IDA is at

  6. User's manual for three dimensional FDTD version A code for scattering from frequency-independent dielectric materials

    NASA Technical Reports Server (NTRS)

    Beggs, John H.; Luebbers, Raymond J.; Kunz, Karl S.

    1991-01-01

    The Finite Difference Time Domain Electromagnetic Scattering Code Version A is a three dimensional numerical electromagnetic scattering code based upon the Finite Difference Time Domain Technique (FDTD). This manual provides a description of the code and corresponding results for the default scattering problem. In addition to the description, the operation, resource requirements, version A code capabilities, a description of each subroutine, a brief discussion of the radar cross section computations, and a discussion of the scattering results.

  7. Reasoning about Users' Actions in a Graphical User Interface.

    ERIC Educational Resources Information Center

    Virvou, Maria; Kabassi, Katerina

    2002-01-01

    Describes a graphical user interface called IFM (Intelligent File Manipulator) that provides intelligent help to users. Explains two underlying reasoning mechanisms, one an adaptation of human plausible reasoning and one that performs goal recognition based on the effects of users' commands; and presents results of an empirical study that…

  8. Study on galloping behavior of iced eight bundle conductor transmission lines

    NASA Astrophysics Data System (ADS)

    Zhou, Linshu; Yan, Bo; Zhang, Liang; Zhou, Song

    2016-02-01

    Wind tunnel test was carried out to obtain the aerodynamic coefficients of an eight bundle conductor accreted with crescent-shaped ice. A user-defined cable element with torsional degree of freedom is developed in ABAQUS software to capture the torsional deformation of the iced conductors during galloping. By means of the user-defined cable element, different damping ratios in in-plane, out-of-plane and torsional directions of the conductors can be defined and the aerodynamic forces varying with their motion status can be exerted on the conductors conveniently when ABAQUS is used to simulate galloping of transmission lines. A wind tunnel test to model galloping of an iced eight bundle conductor segment was carried out, and the validity of the numerical simulation method is demonstrated by the agreement of the galloping orbit of the bundle conductor segment model recorded in the test and that by the numerical simulation. Furthermore, galloping behavior, including dynamic responses, galloping orbits, frequencies, vibration modes and amplitudes, of typical iced eight bundle conductor transmission lines in the cases of different span lengths, initial tensions in sub-conductors, wind velocities, angles of wind attack and damping ratios is studied, and the galloping behavior of the lines with internal resonance conditions is discussed. The obtained results may provide a fundamental tool for the development of anti-galloping techniques of eight bundle conductor transmission lines.

  9. User Behavior Analytics

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Turcotte, Melissa; Moore, Juston Shane

    User Behaviour Analytics is the tracking, collecting and assessing of user data and activities. The goal is to detect misuse of user credentials by developing models for the normal behaviour of user credentials within a computer network and detect outliers with respect to their baseline.

  10. Circuit design tool. User's manual, revision 2

    NASA Technical Reports Server (NTRS)

    Miyake, Keith M.; Smith, Donald E.

    1992-01-01

    The CAM chip design was produced in a UNIX software environment using a design tool that supports definition of digital electronic modules, composition of these modules into higher level circuits, and event-driven simulation of these circuits. Our design tool provides an interface whose goals include straightforward but flexible primitive module definition and circuit composition, efficient simulation, and a debugging environment that facilitates design verification and alteration. The tool provides a set of primitive modules which can be composed into higher level circuits. Each module is a C-language subroutine that uses a set of interface protocols understood by the design tool. Primitives can be altered simply by recoding their C-code image; in addition new primitives can be added allowing higher level circuits to be described in C-code rather than as a composition of primitive modules--this feature can greatly enhance the speed of simulation.

  11. The CMC/3DPNS computer program for prediction of three-dimensional, subsonic, turbulent aerodynamic juncture region flow. Volume 3: Programmers' manual

    NASA Technical Reports Server (NTRS)

    Orzechowski, J. A.

    1982-01-01

    The CMC fluid mechanics program system was developed to transmit the theoretical evolution of finite element numerical solution methodology, applied to nonlinear field problems into a versatile computer code for comprehensive flow field analysis. A detailed view of the code from the standpoint of a computer programmer's use is presented. A system macroflow chart and detailed flow charts of several routines necessary to interact with a theoretican/user to modify the operation of this program are presented. All subroutines and details of usage, primarily for input and output routines are described. Integer and real scalars and a cross reference list denoting subroutine usage for these scalars are outlined. Entry points in dynamic storage vector IZ; the lengths of each vector accompanying the scalar definitions are described. A listing of the routines peculiar to the standard test case and a listing of the input deck and printout for this case are included.

  12. An interactive modular design for computerized photometry in spectrochemical analysis

    NASA Technical Reports Server (NTRS)

    Bair, V. L.

    1980-01-01

    A general functional description of totally automatic photometry of emission spectra is not available for an operating environment in which the sample compositions and analysis procedures are low-volume and non-routine. The advantages of using an interactive approach to computer control in such an operating environment are demonstrated. This approach includes modular subroutines selected at multiple-option, menu-style decision points. This style of programming is used to trace elemental determinations, including the automated reading of spectrographic plates produced by a 3.4 m Ebert mount spectrograph using a dc-arc in an argon atmosphere. The simplified control logic and modular subroutine approach facilitates innovative research and program development, yet is easily adapted to routine tasks. Operator confidence and control are increased by the built-in options including degree of automation, amount of intermediate data printed out, amount of user prompting, and multidirectional decision points.

  13. Comparing Text-based and Graphic User Interfaces for Novice and Expert Users

    PubMed Central

    Chen, Jung-Wei; Zhang, Jiajie

    2007-01-01

    Graphic User Interface (GUI) is commonly considered to be superior to Text-based User Interface (TUI). This study compares GUI and TUI in an electronic dental record system. Several usability analysis techniques compared the relative effectiveness of a GUI and a TUI. Expert users and novice users were evaluated in time required and steps needed to complete the task. A within-subject design was used to evaluate if the experience with either interface will affect task performance. The results show that the GUI interface was not better than the TUI for expert users. GUI interface was better for novice users. For novice users there was a learning transfer effect from TUI to GUI. This means a user interface is user-friendly or not depending on the mapping between the user interface and tasks. GUI by itself may or may not be better than TUI. PMID:18693811

  14. Comparing Text-based and Graphic User Interfaces for novice and expert users.

    PubMed

    Chen, Jung-Wei; Zhang, Jiajie

    2007-10-11

    Graphic User Interface (GUI) is commonly considered to be superior to Text-based User Interface (TUI). This study compares GUI and TUI in an electronic dental record system. Several usability analysis techniques compared the relative effectiveness of a GUI and a TUI. Expert users and novice users were evaluated in time required and steps needed to complete the task. A within-subject design was used to evaluate if the experience with either interface will affect task performance. The results show that the GUI interface was not better than the TUI for expert users. GUI interface was better for novice users. For novice users there was a learning transfer effect from TUI to GUI. This means a user interface is user-friendly or not depending on the mapping between the user interface and tasks. GUI by itself may or may not be better than TUI.

  15. Franklin: User Experiences

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    National Energy Research Supercomputing Center; He, Yun; Kramer, William T.C.

    2008-05-07

    The newest workhorse of the National Energy Research Scientific Computing Center is a Cray XT4 with 9,736 dual core nodes. This paper summarizes Franklin user experiences from friendly early user period to production period. Selected successful user stories along with top issues affecting user experiences are presented.

  16. Investigating Users' Requirements

    PubMed Central

    Walker, Deborah S.; Lee, Wen-Yu; Skov, Neil M.; Berger, Carl F.; Athley, Brian D.

    2002-01-01

    Objective: User data and information about anatomy education were used to guide development of a learning environment that is efficient and effective. The research question focused on how to design instructional software suitable for the educational goals of different groups of users of the Visible Human data set. The ultimate goal of the study was to provide options for students and teachers to use different anatomy learning modules corresponding to key topics, for course work and professional training. Design: The research used both qualitative and quantitative methods. It was driven by the belief that good instructional design must address learning context information and pedagogic content information. The data collection emphasized measurement of users' perspectives, experience, and demands in anatomy learning. Measurement: Users' requirements elicited from 12 focus groups were combined and rated by 11 researchers. Collective data were sorted and analyzed by use of multidimensional scaling and cluster analysis. Results: A set of functions and features in high demand across all groups of users was suggested by the results. However, several subgroups of users shared distinct demands. The design of the learning modules will encompass both unified core components and user-specific applications. The design templates will allow sufficient flexibility for dynamic insertion of different learning applications for different users. Conclusion: This study describes how users' requirements, associated with users' learning experiences, were systematically collected and analyzed and then transformed into guidelines informing the iterative design of multiple learning modules. Information about learning challenges and processes was gathered to define essential anatomy teaching strategies. A prototype instrument to design and polish the Visible Human user interface system is currently being developed using ideas and feedback from users. PMID:12087112

  17. Health-Related Quality of Life among Chronic Opioid Users, Nonchronic Opioid Users, and Nonopioid Users with Chronic Noncancer Pain.

    PubMed

    Hayes, Corey J; Li, Xiaocong; Li, Chenghui; Shah, Anuj; Kathe, Niranjan; Bhandari, Naleen Raj; Payakachat, Nalin

    2018-02-25

    Evaluate the association between opioid therapy and health-related quality of life (HRQoL) in participants with chronic, noncancer pain (CNCP). Medical Expenditure Panel Survey Longitudinal, Medical Conditions, and Prescription Files. Using a retrospective cohort study design, the Mental Health Component (MCS12) and Physical Health Component (PCS12) scores of the Short Form-12 Version 2 were assessed to measure mental and physical HRQoL. Chronic, noncancer pain participants were classified as chronic, nonchronic, and nonopioid users. One-to-one propensity score matching was employed to match chronic opioid users to nonchronic opioid users plus nonchronic opioid users and chronic opioid users to nonopioid users. A total of 5,876 participants were identified. After matching, PCS12 was not significantly different between nonchronic versus nonopioid users (LSM Diff = -0.98, 95% CI: -2.07, 0.10), chronic versus nonopioid users (LSM Diff = -2.24, 95% CI: -4.58, 0.10), or chronic versus nonchronic opioid users (LSM Diff = -2.23, 95% CI: -4.53, 0.05). Similarly, MCS12 was not significantly different between nonchronic versus nonopioid users (LSM Diff = 0.76, 95% CI: -0.46, 1.98), chronic versus nonopioid users (LSM Diff = 1.08, 95% CI: -1.26, 3.42), or chronic versus nonchronic opioid users (LSM Diff = -0.57, 95% CI: -2.90, 1.77). Clinicians should evaluate opioid use in participants with CNCP as opioid use is not correlated with better HRQoL. © Health Research and Educational Trust.

  18. Adding and Removing Web Area Users, and Changing User Roles

    EPA Pesticide Factsheets

    Webmasters can add users to a web area, and assign or change roles, which define the actions a user is able to take in the web area. Non-webmasters must use a request form to add users and change roles.

  19. From users involvement to users' needs understanding: a case study.

    PubMed

    Niès, Julie; Pelayo, Sylvia

    2010-04-01

    Companies developing and commercializing Healthcare IT applications may decide to involve the users in the software development lifecycle in order to better understand the users' needs and to optimize their products. Unfortunately direct developers-users dialogues are not sufficient to ensure a proper understanding of the users' needs. It is also necessary to involve human factors specialists to analyze the users' expression of their needs and to properly formalize the requirements for design purposes. The objective of this paper is to present a case study reporting the collaborative work between HF experts and a company developing and commercializing a CPOE. This study shows how this collaboration helps resolve the limits of direct users involvement and usual problems pertaining to users' needs description and understanding. The company participating in the study has implemented a procedure to convene regular meetings allowing direct exchanges between the development team and users' representatives. Those meetings aim at getting users' feedbacks on the existing products and at validating further developments. In parallel with usual HF methods supporting the analysis of the work system (onsite observations followed by debriefing interviews) and the usability evaluation of the application (usability inspection and usability tests), HF experts took the opportunity of the meetings organized by the company to collect, re-interpret and re-formulate the needs expressed by the users. The developers perceive the physicians' requirements concerning the display of the patient's list of medication as contradictory. In a previous meeting round the users had required a detailed view of the medication list against the synthesized existing one. Once this requirement satisfied, the users participating in the current meeting round require a synthesized view against the existing detailed one. The development team is unable to understand what they perceive as a reverse claim. Relying

  20. A GUI-based Tool for Bridging the Gap between Models and Process-Oriented Studies

    NASA Astrophysics Data System (ADS)

    Kornfeld, A.; Van der Tol, C.; Berry, J. A.

    2014-12-01

    Models used for simulation of photosynthesis and transpiration by canopies of terrestrial plants typically have subroutines such as STOMATA.F90, PHOSIB.F90 or BIOCHEM.m that solve for photosynthesis and associated processes. Key parameters such as the Vmax for Rubisco and temperature response parameters are required by these subroutines. These are often taken from the literature or determined by separate analysis of gas exchange experiments. It is useful to note however that subroutines can be extracted and run as standalone models to simulate leaf responses collected in gas exchange experiments. Furthermore, there are excellent non-linear fitting tools that can be used to optimize the parameter values in these models to fit the observations. Ideally the Vmax fit in this way should be the same as that determined by a separate analysis, but it may not because of interactions with other kinetic constants and the temperature dependence of these in the full subroutine. We submit that it is more useful to fit the complete model to the calibration experiments rather as disaggregated constants. We designed a graphical user interface (GUI) based tool that uses gas exchange photosynthesis data to directly estimate model parameters in the SCOPE (Soil Canopy Observation, Photochemistry and Energy fluxes) model and, at the same time, allow researchers to change parameters interactively to visualize how variation in model parameters affect predicted outcomes such as photosynthetic rates, electron transport, and chlorophyll fluorescence. We have also ported some of this functionality to an Excel spreadsheet, which could be used as a teaching tool to help integrate process-oriented and model-oriented studies.

  1. User's Manual for the Object User Interface (OUI): An Environmental Resource Modeling Framework

    USGS Publications Warehouse

    Markstrom, Steven L.; Koczot, Kathryn M.

    2008-01-01

    The Object User Interface is a computer application that provides a framework for coupling environmental-resource models and for managing associated temporal and spatial data. The Object User Interface is designed to be easily extensible to incorporate models and data interfaces defined by the user. Additionally, the Object User Interface is highly configurable through the use of a user-modifiable, text-based control file that is written in the eXtensible Markup Language. The Object User Interface user's manual provides (1) installation instructions, (2) an overview of the graphical user interface, (3) a description of the software tools, (4) a project example, and (5) specifications for user configuration and extension.

  2. The User Experience

    ERIC Educational Resources Information Center

    Schmidt, Aaron

    2010-01-01

    User experience (UX) is about arranging the elements of a product or service to optimize how people will interact with it. In this article, the author talks about the importance of user experience and discusses the design of user experiences in libraries. He first looks at what UX is. Then he describes three kinds of user experience design: (1)…

  3. Sexual behavior differences between amphetamine-type stimulants users and heroin users.

    PubMed

    Jia, Zhen-jun; Yan, Shi-yan; Bao, Yan-ping; Lian, Zhi; Zhang, Hao-ran; Liu, Zhi-min

    2013-01-01

    To explore the sexual behavior of amphetamine-type stimulant (ATS) users and heroin users, and to find out the dangerous sexual behaviors, even related risk factors among them. Four hundred thirty-eight ATS users and 524 heroin users were recruited in 10 compulsory detoxification treatment centers and voluntary detoxification centers in Beijing, Shenzhen, Guangzhou, Xi'an, and Taiyuan. Their sociodemographic characteristics, history of drug taking, and sexual behaviors were surveyed. Many variables of sociodemographic characteristics and sexual behaviors were significantly different between ATS users and heroin users (P < 0.05). Dangerous sexual behaviors among ATS users include sexual intercourse often or each time after taking drug (30.1%), multiple sexual intercourse (16.5%), casual sex partners (34.0%), homosexual partners (2.5%), and never or occasionally using condom with a steady sex partner (79.3%) or with casual sex partners (39.1%). The rate of ever-infecting sexually transmitted disease (STD) was high in both the groups (ATS, 20.5%; heroin, 30.9%). Sexual behavior is the main way to transmit STD and human immunodeficiency virus among ATS users. The study results will promote the government's awareness of the issue and take necessary steps to slow the spread of STD and human immunodeficiency virus among the ATS users.

  4. User's guide to four-body and three-body trajectory optimization programs

    NASA Technical Reports Server (NTRS)

    Pu, C. L.; Edelbaum, T. N.

    1974-01-01

    A collection of computer programs and subroutines written in FORTRAN to calculate 4-body (sun-earth-moon-space) and 3-body (earth-moon-space) optimal trajectories is presented. The programs incorporate a variable step integration technique and a quadrature formula to correct single step errors. The programs provide capability to solve initial value problem, two point boundary value problem of a transfer from a given initial position to a given final position in fixed time, optimal 2-impulse transfer from an earth parking orbit of given inclination to a given final position and velocity in fixed time and optimal 3-impulse transfer from a given position to a given final position and velocity in fixed time.

  5. A Study of Adaptive Image Compression Techniques.

    DTIC Science & Technology

    1980-02-01

    1 3101 171 11 3 2 3 3751 3 053 - 17 314 3464 38 31124 3 440 3300 N. - 4 N.5 .V6 it 2018 3i13 1 00 1857 .743 13170 9 2 .531) 2232 2 I 2 14 79 2 236 1...CONTAINS THE OPTIMAL ALICCATION TO EACH C BLOCK C C ROUTINES CALLED C C RESALL RESOURCE ALLOCATION (USER BOUTINE ) C C C C SUBROUTINE OBITAL ( INDAT

  6. Database Design and Management in Engineering Optimization.

    DTIC Science & Technology

    1988-02-01

    scientific and engineer- Q.- ’ method In the mid-19SOs along with modern digital com- ing applications. The paper highlights the difference puters, have made...is continuously tion software can call standard subroutines from the DBMS redefined in an application program, DDL must have j libary to define...operations. .. " type data usually encountered in engineering applications. GFDGT: Computes the number of digits needed to display " "’ A user

  7. Project MAC Progress Report 11

    DTIC Science & Technology

    1974-12-01

    whether a subroutine would be useful as a part of some larger program , and, if so, how to use it [8]. The programming methodology employed by CALICO...7. Seriff, Marc, How to Write Programs for the CALICO Environment. SYS. 14.04 (unpublished). 8. Reeve, Chris, Marty Draper, D. E. Burmaster, and J...Introduction Automatic Programming Group A. Introduction B. Understanding How a User Might Interact with a Knowledge-Based Application System C

  8. A Combinatorial Geometry Computer Description of the XR311 Vehicle

    DTIC Science & Technology

    1978-04-01

    cards or magnetic tape. The shot line output of the GRID subroutine of the GIFT code is also stored on magnetic tape for future vulnera- bility...descriptions as processed by the Geometric Information For Targets ( GIFT )2 computer code. This report documents the COM-GEOM target description for all...72, March 1974. ’L.W. Bains and M.J. Reisinger, "The GIFT Code User Manual, VOL 1, Introduction and Input Requirements, " Ballistic Research

  9. Instructions for the use of the CIVM-Jet 4C finite-strain computer code to calculate the transient structural responses of partial and/or complete arbitrarily-curved rings subjected to fragment impact

    NASA Technical Reports Server (NTRS)

    Rodal, J. J. A.; French, S. E.; Witmer, E. A.; Stagliano, T. R.

    1979-01-01

    The CIVM-JET 4C computer program for the 'finite strain' analysis of 2 d transient structural responses of complete or partial rings and beams subjected to fragment impact stored on tape as a series of individual files. Which subroutines are found in these files are described in detail. All references to the CIVM-JET 4C program are made assuming that the user has a copy of NASA CR-134907 (ASRL TR 154-9) which serves as a user's guide to (1) the CIVM-JET 4B computer code and (2) the CIVM-JET 4C computer code 'with the use of the modified input instructions' attached hereto.

  10. WINDOWAC (Wing Design Optimization With Aeroelastic Constraints): Program manual

    NASA Technical Reports Server (NTRS)

    Haftka, R. T.; Starnes, J. H., Jr.

    1974-01-01

    User and programer documentation for the WIDOWAC programs is given. WIDOWAC may be used for the design of minimum mass wing structures subjected to flutter, strength, and minimum gage constraints. The wing structure is modeled by finite elements, flutter conditions may be both subsonic and supersonic, and mathematical programing methods are used for the optimization procedure. The user documentation gives general directions on how the programs may be used and describes their limitations; in addition, program input and output are described, and example problems are presented. A discussion of computational algorithms and flow charts of the WIDOWAC programs and major subroutines is also given.

  11. Applications of Multiconductor Transmission Line Theory to the Prediction of Cable Coupling. Volume 7. Digital Computer Programs for the Analysis of Multiconductor Transmission Lines

    DTIC Science & Technology

    1977-07-01

    on an IBM 370/165 computer at The University of Kentucky using the Fortran IV, G level compiler and should be easily implemented on other computers...order as the columns of T. 3.5.3 Subroutines NROOT and EIGEN Subroutines NROOT and EIGEN are a set of subroutines from the IBM Scientific Subroutine...November 1975). [10] System/360 Scientific Subroutine Package, Version III, Fifth Edition (August 1970), IBM Corporation, Technical Publications

  12. IWR-MAIN Water Use Forecasting System. Version 5.1. User’s Manual and System Description

    DTIC Science & Technology

    1987-12-01

    Crosschecks for Input Data 1-68 11-1 Organization of the IWR-MAIN System H-8 11-2 Example of Econometric Demand Model 11-9 11-3 Example of Unit Use Coefficient...Unaccounted (entry does not affect default Loss and free service calculations) Y Conservation Data City Name: Test City USA Fl-Hetp, F2-return to monu, F4...socioeconomic data. 1-11 (1) Internal Growth Models The IWR-MAIN program contains a subroutine called GROWTH which uses econometric growth models based on

  13. AQUA-USERS: AQUAculture USEr Driven Operational Remote Sensing Information Services

    NASA Astrophysics Data System (ADS)

    Laanen, Marnix; Poser, Kathrin; Peters, Steef; de Reus, Nils; Ghebrehiwot, Semhar; Eleveld, Marieke; Miller, Peter; Groom, Steve; Clements, Oliver; Kurekin, Andrey; Martinez Vicente, Victor; Brotas, Vanda; Sa, Carolina; Couto, Andre; Brito, Ana; Amorim, Ana; Dale, Trine; Sorensen, Kai; Boye Hansen, Lars; Huber, Silvia; Kaas, Hanne; Andersson, Henrik; Icely, John; Fragoso, Bruno

    2015-12-01

    The FP7 project AQUA-USERS provides the aquaculture industry with user-relevant and timely information based on the most up-to-date satellite data and innovative optical in-situ measurements. Its key purpose is to develop an application that brings together satellite information on water quality and temperature with in-situ observations as well as relevant weather prediction and met-ocean data. The application and its underlying database are linked to a decision support system that includes a set of (user-determined) management options. Specific focus is on the development of indicators for aquaculture management including indicators for harmful algae bloom (HAB) events. The methods and services developed within AQUA-USERS are tested by the members of the user board, who represent different geographic areas and aquaculture production systems.

  14. Investigation on low velocity impact resistance of SMA composite material

    NASA Astrophysics Data System (ADS)

    Hu, Dianyin; Zhang, Long; Wang, Rongqiao; Zhang, Xiaoyong

    2016-04-01

    A method to improve low velocity impact resistance of aeroengine composite casing using shape memory alloy's properties of shape memory(SM) and super-elasticity(SE) is proposed in this study. Firstly, a numerical modeling of SMA reinforced composite laminate under low velocity impact load with impact velocity of 10 m/s is established based on its constitutive model implemented by the VUMAT subroutine of commercial software ABAQUS. Secondly, the responses of SMA composite laminate including stress and deflection distributions were achieved through transient analysis under low velocity impact load. Numerical results show that both peak stress and deflection values of SMA composite laminate are less than that without SMA, which proves that embedding SMA into the composite structure can effectively improve the low velocity impact performance of composite structure. Finally, the influence of SM and SE on low velocity impact resistance is quantitatively investigated. The values of peak stress and deflection of SMA composite based on SM property decrease by 18.28% and 9.43% respectively, compared with those without SMA, instead of 12.87% and 5.19% based on SE. In conclusion, this proposed model described the impact damage of SMA composite structure and turned to be a more beneficial method to enhance the impact resistance by utilizing SM effect.

  15. On Using Homogeneous Polynomials To Design Anisotropic Yield Functions With Tension/Compression Symmetry/Assymetry

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Soare, S.; Cazacu, O.; Yoon, J. W.

    With few exceptions, non-quadratic homogeneous polynomials have received little attention as possible candidates for yield functions. One reason might be that not every such polynomial is a convex function. In this paper we show that homogeneous polynomials can be used to develop powerful anisotropic yield criteria, and that imposing simple constraints on the identification process leads, aposteriori, to the desired convexity property. It is shown that combinations of such polynomials allow for modeling yielding properties of metallic materials with any crystal structure, i.e. both cubic and hexagonal which display strength differential effects. Extensions of the proposed criteria to 3D stressmore » states are also presented. We apply these criteria to the description of the aluminum alloy AA2090T3. We prove that a sixth order orthotropic homogeneous polynomial is capable of a satisfactory description of this alloy. Next, applications to the deep drawing of a cylindrical cup are presented. The newly proposed criteria were implemented as UMAT subroutines into the commercial FE code ABAQUS. We were able to predict six ears on the AA2090T3 cup's profile. Finally, we show that a tension/compression asymmetry in yielding can have an important effect on the earing profile.« less

  16. On Using Homogeneous Polynomials To Design Anisotropic Yield Functions With Tension/Compression Symmetry/Assymetry

    NASA Astrophysics Data System (ADS)

    Soare, S.; Yoon, J. W.; Cazacu, O.

    2007-05-01

    With few exceptions, non-quadratic homogeneous polynomials have received little attention as possible candidates for yield functions. One reason might be that not every such polynomial is a convex function. In this paper we show that homogeneous polynomials can be used to develop powerful anisotropic yield criteria, and that imposing simple constraints on the identification process leads, aposteriori, to the desired convexity property. It is shown that combinations of such polynomials allow for modeling yielding properties of metallic materials with any crystal structure, i.e. both cubic and hexagonal which display strength differential effects. Extensions of the proposed criteria to 3D stress states are also presented. We apply these criteria to the description of the aluminum alloy AA2090T3. We prove that a sixth order orthotropic homogeneous polynomial is capable of a satisfactory description of this alloy. Next, applications to the deep drawing of a cylindrical cup are presented. The newly proposed criteria were implemented as UMAT subroutines into the commercial FE code ABAQUS. We were able to predict six ears on the AA2090T3 cup's profile. Finally, we show that a tension/compression asymmetry in yielding can have an important effect on the earing profile.

  17. WASP: A flexible FORTRAN 4 computer code for calculating water and steam properties

    NASA Technical Reports Server (NTRS)

    Hendricks, R. C.; Peller, I. C.; Baron, A. K.

    1973-01-01

    A FORTRAN 4 subprogram, WASP, was developed to calculate the thermodynamic and transport properties of water and steam. The temperature range is from the triple point to 1750 K, and the pressure range is from 0.1 to 100 MN/m2 (1 to 1000 bars) for the thermodynamic properties and to 50 MN/m2 (500 bars) for thermal conductivity and to 80 MN/m2 (800 bars) for viscosity. WASP accepts any two of pressure, temperature, and density as input conditions. In addition, pressure and either entropy or enthalpy are also allowable input variables. This flexibility is especially useful in cycle analysis. The properties available in any combination as output include temperature, density, pressure, entropy, enthalpy, specific heats, sonic velocity, viscosity, thermal conductivity, surface tension, and the Laplace constant. The subroutine structure is modular so that the user can choose only those subroutines necessary to his calculations. Metastable calculations can also be made by using WASP.

  18. Generalized environmental control and life support system computer program (G1894), phase 3

    NASA Technical Reports Server (NTRS)

    Mcenulty, R. E.

    1978-01-01

    The work performed during Phase 3 of the Generalized Environmental Control Life Support System (ECLSS) Computer Program is reported. Phase 3 of this program covered the period from December 1977 to September 1978. The computerized simulation of the Shuttle Orbiter ECLSS was upgraded in the following areas: (1) the payload loop of the Shuttle simulation was completely recoded and checked out; (2) the Shuttle simulation water and freon loop initialization logic was simplified to permit easier program input for the user; (3) the computerized simulation was modified to accept the WASP subroutine, which is a subroutine to evaluate thermal properties of water and freon; (4) the 1108 operating system was upgraded by LEC; (5) the Shuttle simulation was modified to permit failure cases which simulate zero component flow values; and (6) the Shuttle SEPS version was modified and secure files were setup on the 1108 and 1110 systems to permit simulation runs to be made from remote terminals.

  19. Raster graphics display library

    NASA Technical Reports Server (NTRS)

    Grimsrud, Anders; Stephenson, Michael B.

    1987-01-01

    The Raster Graphics Display Library (RGDL) is a high level subroutine package that give the advanced raster graphics display capabilities needed. The RGDL uses FORTRAN source code routines to build subroutines modular enough to use as stand-alone routines in a black box type of environment. Six examples are presented which will teach the use of RGDL in the fastest, most complete way possible. Routines within the display library that are used to produce raster graphics are presented in alphabetical order, each on a separate page. Each user-callable routine is described by function and calling parameters. All common blocks that are used in the display library are listed and the use of each variable within each common block is discussed. A reference on the include files that are necessary to compile the display library is contained. Each include file and its purpose are listed. The link map for MOVIE.BYU version 6, a general purpose computer graphics display system that uses RGDL software, is also contained.

  20. Computer routines for probability distributions, random numbers, and related functions

    USGS Publications Warehouse

    Kirby, W.

    1983-01-01

    Use of previously coded and tested subroutines simplifies and speeds up program development and testing. This report presents routines that can be used to calculate various probability distributions and other functions of importance in statistical hydrology. The routines are designed as general-purpose Fortran subroutines and functions to be called from user-written main progress. The probability distributions provided include the beta, chi-square, gamma, Gaussian (normal), Pearson Type III (tables and approximation), and Weibull. Also provided are the distributions of the Grubbs-Beck outlier test, Kolmogorov 's and Smirnov 's D, Student 's t, noncentral t (approximate), and Snedecor F. Other mathematical functions include the Bessel function, I sub o, gamma and log-gamma functions, error functions, and exponential integral. Auxiliary services include sorting and printer-plotting. Random number generators for uniform and normal numbers are provided and may be used with some of the above routines to generate numbers from other distributions. (USGS)

  1. Computer routines for probability distributions, random numbers, and related functions

    USGS Publications Warehouse

    Kirby, W.H.

    1980-01-01

    Use of previously codes and tested subroutines simplifies and speeds up program development and testing. This report presents routines that can be used to calculate various probability distributions and other functions of importance in statistical hydrology. The routines are designed as general-purpose Fortran subroutines and functions to be called from user-written main programs. The probability distributions provided include the beta, chisquare, gamma, Gaussian (normal), Pearson Type III (tables and approximation), and Weibull. Also provided are the distributions of the Grubbs-Beck outlier test, Kolmogorov 's and Smirnov 's D, Student 's t, noncentral t (approximate), and Snedecor F tests. Other mathematical functions include the Bessel function I (subzero), gamma and log-gamma functions, error functions and exponential integral. Auxiliary services include sorting and printer plotting. Random number generators for uniform and normal numbers are provided and may be used with some of the above routines to generate numbers from other distributions. (USGS)

  2. One Dimensional Analysis of Inertially Confined Plasmas.

    DTIC Science & Technology

    1982-03-01

    Confinement Fuel Pellet’ - 3 2 General Flowchart for Program MOXNEX 8 3 General Program Organization of Subroutine ALPHA1 - 1J- 4 Values of <ov...is dumped in the current cell. Subprogram ALPHA1 calls 14 other subroutines to complete its tasks. General program organization is seen in Figure 3...OEROSITION T Figure 3. General Program Organization of Subroutine ALPHA1 6. Subroutine HTFLX. This subroutine computes the energy transfer

  3. Do recreational cannabis users, unlicensed and licensed medical cannabis users form distinct groups?

    PubMed

    Sznitman, Sharon R

    2017-04-01

    This study aims to gain a more nuanced perspective on the differences between recreationally and medically motivated cannabis use by distinguishing between people who use cannabis for recreational purposes, unlicensed and licensed medical users. Data collection was conducted online from a convenience sample of 1479 Israeli cannabis users. Multinomial regression analysis compared unlicensed medical users (38%) with recreational (42%) and licensed medical (5.6%) users in terms of sociodemographics, mode, frequency and problematic cannabis use. There were more variables distinguishing unlicensed from licensed users than there were distinguishing features between unlicensed and recreational users. Recreational users were more likely to be male, less likely to eat cannabis, to use cannabis frequently and to use alone and before midday than unlicensed users. Licensed users were older than unlicensed users, they reported less hours feeling stoned, less cannabis use problems and they were more likely to report cannabis use patterns analogous of medication administration for chronic problems (frequent use, vaping, use alone and use before midday). This study suggests that a sizable proportion of cannabis users in Israel self-prescribe cannabis and that licensed medical cannabis users differ from unlicensed users. This is, in turn, suggestive of a rigorous medicalized cannabis program that does not function as a backdoor for legal access to recreational use. However, due to methodological limitations this conclusion is only suggestive. The most meaningful differences across recreational, unlicensed and licensed users were mode and patterns of use rather than cannabis use problems. Current screening tools for cannabis use problems may, however, not be well suited to assess such problems in medically motivated users. Indeed, when screening for problematic cannabis use there is a need for a more careful consideration of whether or not cannabis use is medically motivated

  4. Epidemics of HIV, HCV and syphilis infection among synthetic drugs only users, heroin-only users and poly-drug users in Southwest China.

    PubMed

    Su, Shu; Mao, Limin; Zhao, Jinxian; Chen, Liang; Jing, Jun; Cheng, Feng; Zhang, Lei

    2018-04-26

    The number of poly-drug users who mix use heroin and synthetic drugs (SD) is increasing worldwide. The objective of this study is to measure the risk factors for being infected with hepatitis C (HCV), human immunodeficiency virus (HIV) and syphilis among SD-only users, heroin-only users and poly-drug users. A cross-sectional study was conducted in 2015 from a national HIV surveillance site in Southwest China, 447 poly-drug, 526 SD-only and 318 heroin-only users were recruited. Poly-drug users have higher drug-use frequency, higher rates of drug-sharing and unsafe sexual acts than other users (p < 0.05). About a third (36.7%) of poly-drug users experienced sexual arousal due to drug effects, which is higher than the rate among other drug users. Poly-drug users had the highest prevalence of HIV (10.5%) and syphilis (3.6%), but heroin-only users had the highest prevalence of HCV (66.0%) (all p < 0.05) among three groups. Logistic regression shows among poly-drug users, having sex following drug consumption and using drugs ≥1/day were the major risk factors for both HIV (Adjusted odds ratio (AOR) = 2.4, 95% CI [1.8-3.4]; 2.3, [1.6-3.1]) and syphilis infection (AOR = 4.1, [2.1-6.9]; 3.9, [1.8-5.4]). Elevated risk of both HIV and syphilis infection have been established among poly-drug users.

  5. ITS user services document

    DOT National Transportation Integrated Search

    2005-01-01

    Intelligent Transportation System (ITS) user services are surface transportation services that can be provided by some aspect of ITS. These ITS user services document what ITS should do from the user's perspective. A broad range of users are consider...

  6. How to Develop a User Interface That Your Real Users Will Love

    ERIC Educational Resources Information Center

    Phillips, Donald

    2012-01-01

    A "user interface" is the part of an interactive system that bridges the user and the underlying functionality of the system. But people sometimes forget that the best interfaces will provide a platform to optimize the users' interactions so that they support and extend the users' activities in effective, useful, and usable ways. To look at it…

  7. Speaking of Users: On User Discourses in the Field of Public Libraries

    ERIC Educational Resources Information Center

    Hedemark, Ase; Hedman, Jenny; Sundin, Olof

    2005-01-01

    Introduction: The aim of the study reported is to examine user discourses identified in the Swedish public library field. The following questions are posed: What user discourses can be found and what characterises them? How are users categorised and what does this categorisation imply? The departure point in this paper is that the ways users are…

  8. RT-PCR quantification of periodontal pathogens in crack users and non-users.

    PubMed

    Casarin, M; Antoniazzi, R P; Vaucher, R A; Feldens, C A; Zanatta, F B

    2017-04-01

    To compare counts of Aggregatibacter actinomycetemcomitans, Prevotella intermedia, Porphyromonas gingivalis and Fusobacterium nucleatum between crack users and non-users. A cross-sectional study was conducted involving seventy-four crack cocaine users and eighty-one non-users matched for age, gender and tobacco use. Demographic and clinical variables were analysed. Subgingival bacterial samples were collected from four sites with the greatest probing depths and were analysed using real-time polymerase chain reaction. No significant difference was found in the prevalence of total counts for each bacterial species analysed between groups. However, crack users had a 1.85 (95% CI: 1.03-3.31), 2.19 (95% CI 1.24-3.88), 2.53 (95% CI 1.27-5.04) and 2.40 (95% CI 1.22-4.75) greater probability of having the higher counts (≥75th percentile) for Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia and Fusobacterium nucleatum, respectively. Although some crack users had higher (>75th percentile) bacterial counts for Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia and Fusobacterium nucleatum, total counts did not differ between crack users and non-users, leading to the hypothesis that the higher occurrence of periodontitis on crack users may be related to other non-bacterial factors. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. Cognitive function and mood in MDMA/THC users, THC users and non-drug using controls.

    PubMed

    Lamers, C T J; Bechara, A; Rizzo, M; Ramaekers, J G

    2006-03-01

    Repeated ecstasy (MDMA) use is reported to impair cognition and cause increased feelings of depression and anxiety. Yet, many relevant studies have failed to control for use of drugs other than MDMA, especially marijuana (THC). To address these confounding effects we compared behavioural performance of 11 MDMA/THC users, 15 THC users and 15 non-drug users matched for age and intellect. We tested the hypothesis that reported feelings of depression and anxiety and cognitive impairment (memory, executive function and decision making) are more severe in MDMA/THC users than in THC users. MDMA/THC users reported more intense feelings of depression and anxiety than THC users and non-drug users. Memory function was impaired in both groups of drug users. MDMA/THC users showed slower psychomotor speed and less mental flexibility than non-drug users. THC users exhibited less mental flexibility and performed worse on the decision making task compared to non-drug users but these functions were similar to those in MDMA/THC users. It was concluded that MDMA use is associated with increased feelings of depression and anxiety compared to THC users and non-drug users. THC users were impaired in some cognitive abilities to the same degree as MDMA/THC users, suggesting that some cognitive impairment attributed to MDMA is more likely due to concurrent THC use.

  10. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Rybicki, E.F.; Sutrick, J.S.

    During the second quarter of Phase II, efforts were directed toward three tasks. One was including a subroutine to calculate pressure in the proppant transport model and preparing a users guide and tape for the computer program TUPROP1. The second was directed toward the proppant tracking capability of the program. The last task was combining the fracture geometry model and the proppant transport model. Progress on each of these areas is described. 5 refs., 1 fig., 5 tabs.

  11. Updraft Fixed Bed Gasification Aspen Plus Model

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    2007-09-27

    The updraft fixed bed gasification model provides predictive modeling capabilities for updraft fixed bed gasifiers, when devolatilization data is available. The fixed bed model is constructed using Aspen Plus, process modeling software, coupled with a FORTRAN user kinetic subroutine. Current updraft gasification models created in Aspen Plus have limited predictive capabilities and must be "tuned" to reflect a generalized gas composition as specified in literature or by the gasifier manufacturer. This limits the applicability of the process model.

  12. Program Aids Creation Of X-Y Plots

    NASA Technical Reports Server (NTRS)

    Jeletic, James F.

    1993-01-01

    VEGAS computer program enables application programmers to create X-Y plots in various modes through high-level subroutine calls. Modes consist of passive, autoupdate, and interactive modes. In passive mode, VEGAS takes input data, produces plot, and returns control to application program. In autoupdate mode, forms plots and automatically updates them as more information received. In interactive mode, displays plot and provides popup menus for user to alter appearance of plot or to modify data. Written in FORTRAN 77.

  13. CASPER: A GENERALIZED PROGRAM FOR PLOTTING AND SCALING DATA

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lietzke, M.P.; Smith, R.E.

    A Fortran subroutine was written to scale floating-point data and generate a magnetic tape to plot it on the Calcomp 570 digital plotter. The routine permits a great deal of flexibility, and may be used with any type of FORTRAN or FAP calling program. A simple calling program was also written to permit the user to read in data from cards and plot it without any additional programming. Both the Fortran and binary decks are available. (auth)

  14. A Computer Code for Swirling Turbulent Axisymmetric Recirculating Flows in Practical Isothermal Combustor Geometries

    NASA Technical Reports Server (NTRS)

    Lilley, D. G.; Rhode, D. L.

    1982-01-01

    A primitive pressure-velocity variable finite difference computer code was developed to predict swirling recirculating inert turbulent flows in axisymmetric combustors in general, and for application to a specific idealized combustion chamber with sudden or gradual expansion. The technique involves a staggered grid system for axial and radial velocities, a line relaxation procedure for efficient solution of the equations, a two-equation k-epsilon turbulence model, a stairstep boundary representation of the expansion flow, and realistic accommodation of swirl effects. A user's manual, dealing with the computational problem, showing how the mathematical basis and computational scheme may be translated into a computer program is presented. A flow chart, FORTRAN IV listing, notes about various subroutines and a user's guide are supplied as an aid to prospective users of the code.

  15. Do You Know Your Music Users' Needs? A Library User Survey that Helps Enhance a User-Centered Music Collection

    ERIC Educational Resources Information Center

    Lai, Katie; Chan, Kylie

    2010-01-01

    While many surveys aim primarily at measuring general user satisfaction, this survey is dedicated to understanding music users' needs, usage patterns, and preferences towards various collections. Findings showed dissimilar use behavior and perceived importance of materials between academic- and performance-oriented music users. Needs for different…

  16. Reasons for not using ecstasy: a qualitative study of non-users, ex-light users and ex-moderate users

    PubMed Central

    2012-01-01

    Background Although ecstasy is often consumed in the electronic music scene, not everyone with the opportunity to use it chooses to do so. The objective of this study was to understand the reasons for non-use or the cessation of use, which could provide information for public health interventions. Methods A qualitative reference method was used. Our “snowball” sample group consisted of 53 people who were split into three subgroups: non-users (NU, n = 23), ex-light users (EX-L, n = 12) and ex-moderate users (EX-M, n = 18). Individual, semi-structured interviews were conducted, transcribed and subjected to content analysis with the aid of NVivo8. Results Adverse health effects and personal values were given as reasons for non-use in the three groups. Non-users (NU) and ex-light users (EX-L) provided reasons that included fear of possible effects as well as moral, family and religious objections. Ex-moderate users (EX-M) cited reasons related to health complications and concomitant withdrawal from the electronic music scene. However, most of the ex-moderate users did not rule out the possibility of future use. Conclusions Potential effects and undesirable consequences appear to guide the decisions within the different groups. Prevention might target these motivations. Individuals who have used ecstasy indicate that social and environmental factors are the most important factors. PMID:22583984

  17. User interface support

    NASA Technical Reports Server (NTRS)

    Lewis, Clayton; Wilde, Nick

    1989-01-01

    Space construction will require heavy investment in the development of a wide variety of user interfaces for the computer-based tools that will be involved at every stage of construction operations. Using today's technology, user interface development is very expensive for two reasons: (1) specialized and scarce programming skills are required to implement the necessary graphical representations and complex control regimes for high-quality interfaces; (2) iteration on prototypes is required to meet user and task requirements, since these are difficult to anticipate with current (and foreseeable) design knowledge. We are attacking this problem by building a user interface development tool based on extensions to the spreadsheet model of computation. The tool provides high-level support for graphical user interfaces and permits dynamic modification of interfaces, without requiring conventional programming concepts and skills.

  18. Growth on demand: Reviewing the mechanobiology of stretched skin

    PubMed Central

    Zöllner, Alexander M.; Holland, Maria A.; Honda, Kord S.; Gosain, Arun K.; Kuhl, Ellen

    2013-01-01

    Skin is a highly dynamic, autoregulated, living system that responds to mechanical stretch through a net gain in skin surface area. Tissue expansion uses the concept of controlled overstretch to grow extra skin for defect repair in situ. While the short-term mechanics of stretched skin have been studied intensely by testing explanted tissue samples ex vivo, we know very little about the long-term biomechanics and mechanobiology of living skin in vivo. redHere we explore the long-term effects of mechanical stretch on the characteristics of living skin using a mathematical model for skin growth. We review the molecular mechanisms by which skin responds to mechanical loading and model their effects collectively in a single scalar-valued internal variable, the surface area growth. redThis allows us to adopt a continuum model for growing skin based on the multiplicative decomposition of the deformation gradient into a reversible elastic and an irreversible growth part.redTo demonstrate the inherent modularity of this approach, we implement growth as a user-defined constitutive subroutine into the general purpose implicit finite element program Abaqus/Standard. To illustrate the features of the model, we simulate the controlled area growth of skin in response to tissue expansion with multiple filling points in time. Our results demonstrate that the field theories of continuum mechanics can reliably predict the manipulation of thin biological membranes through mechanical overstretch. Our model could serve as a valuable tool to rationalize clinical process parameters such as expander geometry, expander size, filling volume, filling pressure, and inflation timing to minimize tissue necrosis and maximize patient comfort in plastic and reconstructive surgery. While initially developed for growing skin, our model can easily be generalized to arbitrary biological structures to explore the physiology and pathology of stretch-induced growth of other living systems such as hearts

  19. Customization of user interfaces to reduce errors and enhance user acceptance.

    PubMed

    Burkolter, Dina; Weyers, Benjamin; Kluge, Annette; Luther, Wolfram

    2014-03-01

    Customization is assumed to reduce error and increase user acceptance in the human-machine relation. Reconfiguration gives the operator the option to customize a user interface according to his or her own preferences. An experimental study with 72 computer science students using a simulated process control task was conducted. The reconfiguration group (RG) interactively reconfigured their user interfaces and used the reconfigured user interface in the subsequent test whereas the control group (CG) used a default user interface. Results showed significantly lower error rates and higher acceptance of the RG compared to the CG while there were no significant differences between the groups regarding situation awareness and mental workload. Reconfiguration seems to be promising and therefore warrants further exploration. Copyright © 2013 Elsevier Ltd and The Ergonomics Society. All rights reserved.

  20. Experiences of User Involvement in Mental Health Settings: User Motivations and Benefits.

    PubMed

    Neech, Sophie G B; Scott, Helen; Priest, Helena M; Bradley, Eleanor J; Tweed, Alison E

    2018-05-12

    Despite guidance promoting user involvement, meaningful involvement continues to be debated within services. To effectively implement involvement, it is important to acknowledge why users devote time to such activities. This study explores user representatives' experiences of involvement, including motivations and personal benefits. Thirteen user representatives involved in activities such as staff training and interviews were recruited from a UK National Health Service mental health Trust during 2015. Themes within semi-structured interviews were developed using constructivist grounded theory analysis. Memo-writing, process and focused coding, and core categories supported development of the conceptual framework of being a user representative. Being a user representative was inextricably linked to wellness, yet staff governed opportunities. Making a difference to others and giving back were initial motivating factors. Experiences depended on feeling valued, and the theme of transition captured shifts in identity. User representatives reported increased confidence and wellbeing when supported by staff. However, involvement triggered mental health difficulties, and identified need for regular monitoring and reflection of involvement activities and practice. Services should consider coproduction, where users and staff agree together on involvement definitions. Dedicated involvement workers are crucial to supporting individual wellbeing and monitoring involvement. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  1. Will the User Sink or Swim?: Utilisation of User Education Resources to Advantage.

    ERIC Educational Resources Information Center

    Condon, Patrick

    This discussion centers on the role of libraries in providing postsecondary students and other users with instruction in the use of library resources. It reviews the history of library user education, examines the effects of hard economic times on library instruction, and describes User Education Resources (USER), an Australian database containing…

  2. FEAMAC-CARES Software Coupling Development Effort for CMC Stochastic-Strength-Based Damage Simulation

    NASA Technical Reports Server (NTRS)

    Nemeth, Noel N.; Bednarcyk, Brett A.; Pineda, Evan; Arnold, Steven; Mital, Subodh; Murthy, Pappu; Walton, Owen

    2015-01-01

    Reported here is a coupling of two NASA developed codes: CARES (Ceramics Analysis and Reliability Evaluation of Structures) with the MACGMC composite material analysis code. The resulting code is called FEAMACCARES and is constructed as an Abaqus finite element analysis UMAT (user defined material). Here we describe the FEAMACCARES code and an example problem (taken from the open literature) of a laminated CMC in off-axis loading is shown. FEAMACCARES performs stochastic-strength-based damage simulation response of a CMC under multiaxial loading using elastic stiffness reduction of the failed elements.

  3. Standards for the user interface - Developing a user consensus. [for Space Station Information System

    NASA Technical Reports Server (NTRS)

    Moe, Karen L.; Perkins, Dorothy C.; Szczur, Martha R.

    1987-01-01

    The user support environment (USE) which is a set of software tools for a flexible standard interactive user interface to the Space Station systems, platforms, and payloads is described in detail. Included in the USE concept are a user interface language, a run time environment and user interface management system, support tools, and standards for human interaction methods. The goals and challenges of the USE are discussed as well as a methodology based on prototype demonstrations for involving users in the process of validating the USE concepts. By prototyping the key concepts and salient features of the proposed user interface standards, the user's ability to respond is greatly enhanced.

  4. MADS Users' Guide

    NASA Technical Reports Server (NTRS)

    Moerder, Daniel D.

    2014-01-01

    MADS (Minimization Assistant for Dynamical Systems) is a trajectory optimization code in which a user-specified performance measure is directly minimized, subject to constraints placed on a low-order discretization of user-supplied plant ordinary differential equations. This document describes the mathematical formulation of the set of trajectory optimization problems for which MADS is suitable, and describes the user interface. Usage examples are provided.

  5. Meshing of a Spiral Bevel Gearset with 3D Finite Element Analysis

    NASA Technical Reports Server (NTRS)

    Bibel, George D.; Handschuh, Robert

    1996-01-01

    Recent advances in spiral bevel gear geometry and finite element technology make it practical to conduct a structural analysis and analytically roll the gearset through mesh. With the advent of user specific programming linked to 3D solid modelers and mesh generators, model generation has become greatly automated. Contact algorithms available in general purpose finite element codes eliminate the need for the use and alignment of gap elements. Once the gearset is placed in mesh, user subroutines attached to the FE code easily roll the gearset through mesh. The method is described in detail. Preliminary results for a gearset segment showing the progression of the contact lineload is given as the gears roll through mesh.

  6. SEEK: A FORTRAN optimization program using a feasible directions gradient search

    NASA Technical Reports Server (NTRS)

    Savage, M.

    1995-01-01

    This report describes the use of computer program 'SEEK' which works in conjunction with two user-written subroutines and an input data file to perform an optimization procedure on a user's problem. The optimization method uses a modified feasible directions gradient technique. SEEK is written in ANSI standard Fortran 77, has an object size of about 46K bytes, and can be used on a personal computer running DOS. This report describes the use of the program and discusses the optimizing method. The program use is illustrated with four example problems: a bushing design, a helical coil spring design, a gear mesh design, and a two-parameter Weibull life-reliability curve fit.

  7. TankSIM: A Cryogenic Tank Performance Prediction Program

    NASA Technical Reports Server (NTRS)

    Bolshinskiy, L. G.; Hedayat, A.; Hastings, L. J.; Moder, J. P.; Schnell, A. R.; Sutherlin, S. G.

    2015-01-01

    Developed for predicting the behavior of cryogenic liquids inside propellant tanks under various environmental and operating conditions. Provides a multi-node analysis of pressurization, ullage venting and thermodynamic venting systems (TVS) pressure control using axial jet or spray bar TVS. Allows user to combine several different phases for predicting the liquid behavior for the entire flight mission timeline or part of it. Is a NASA in-house code, based on FORTRAN 90-95 and Intel Visual FORTRAN compiler, but can be used on any other platform (Unix-Linux, Compaq Visual FORTRAN, etc.). The last Version 7, released on December 2014, included detailed User's Manual. Includes the use of several RefPROP subroutines for calculating fluid properties.

  8. Crack-cocaine users have less family cohesion than alcohol users.

    PubMed

    Marchi, Nino C; Scherer, Juliana N; Pachado, Mayra P; Guimarães, Luciano S; Siegmund, Gerson; de Castro, Melina N; Halpern, Silvia; Benzano, Daniela; Formigoni, Maria L; Cruz, Marcelo; Pechansky, Flavio; Kessler, Felix H

    2017-01-01

    Many studies correlate characteristics of family functioning and the development of drug addiction. This study sought to evaluate and compare the family environment styles of two groups of psychoactive substance users: 1) alcohol-only users and 2) crack-cocaine users. Three hundred and sixty-four users of alcohol, crack-cocaine, and other drugs, recruited from research centers in four Brazilian capitals participated in this study. Subjects were evaluated through the Family Environment Scale and the Addiction Severity Index, 6th version (ASI-6). ASI-6 t-scores were compared by analysis of variance (ANOVA) and post-hoc tests. A final model was obtained using a logistic regression analysis. All analyses were adjusted for partner, age, and psychiatric t-score. We found a significant difference between groups in the cohesion subscale (p = 0.044). The post-hoc test revealed a difference of 1.06 points (95%CI 0.11-2.01) between groups 1 (6.45±0.28) and 2 (5.38±0.20). No significant between-group differences were observed in the other subscales. However, categorical analyses of variables regarding family dynamic showed that crack users more often reported that sometimes people in their family hit each other (30.4% vs. 13.2%, p = 0.007) and that people in their family frequently compared each other regarding work and/or school achievement (57.2% vs. 42.6%, p = 0.041). These results suggest that families of crack-cocaine users are less cohesive than families of alcohol users. This type of family environment may affect treatment outcome, and should thus be adequately approached.

  9. FAST User Guide

    NASA Technical Reports Server (NTRS)

    Walatka, Pamela P.; Clucas, Jean; McCabe, R. Kevin; Plessel, Todd; Potter, R.; Cooper, D. M. (Technical Monitor)

    1994-01-01

    The Flow Analysis Software Toolkit, FAST, is a software environment for visualizing data. FAST is a collection of separate programs (modules) that run simultaneously and allow the user to examine the results of numerical and experimental simulations. The user can load data files, perform calculations on the data, visualize the results of these calculations, construct scenes of 3D graphical objects, and plot, animate and record the scenes. Computational Fluid Dynamics (CFD) visualization is the primary intended use of FAST, but FAST can also assist in the analysis of other types of data. FAST combines the capabilities of such programs as PLOT3D, RIP, SURF, and GAS into one environment with modules that share data. Sharing data between modules eliminates the drudgery of transferring data between programs. All the modules in the FAST environment have a consistent, highly interactive graphical user interface. Most commands are entered by pointing and'clicking. The modular construction of FAST makes it flexible and extensible. The environment can be custom configured and new modules can be developed and added as needed. The following modules have been developed for FAST: VIEWER, FILE IO, CALCULATOR, SURFER, TOPOLOGY, PLOTTER, TITLER, TRACER, ARCGRAPH, GQ, SURFERU, SHOTET, and ISOLEVU. A utility is also included to make the inclusion of user defined modules in the FAST environment easy. The VIEWER module is the central control for the FAST environment. From VIEWER, the user can-change object attributes, interactively position objects in three-dimensional space, define and save scenes, create animations, spawn new FAST modules, add additional view windows, and save and execute command scripts. The FAST User Guide uses text and FAST MAPS (graphical representations of the entire user interface) to guide the user through the use of FAST. Chapters include: Maps, Overview, Tips, Getting Started Tutorial, a separate chapter for each module, file formats, and system

  10. Graphic Enhancement of the Aircraft Penetration Model for Use as an Analytic Tool.

    DTIC Science & Technology

    1983-03-01

    internal web of subroutines linked by a ’nervous sytem’ of labelled common blocks." [Ref. 23] Once the user prescribes the parameters for a particular...10 MI4 - ww (A~’ - 0 z . l J- 6,- L a-. 1- ’..u.. - V):LA r w iJ..W 0 d4- Z 9- wtv 4)Lj.J.44 I---M. .. j jU- Wix it 9I’-wku SAXw. Q.3 t- Vd I)4.J13v)v

  11. Graphical User Interfaces and Library Systems: End-User Reactions.

    ERIC Educational Resources Information Center

    Zorn, Margaret; Marshall, Lucy

    1995-01-01

    Describes a study by Parke-Davis Pharmaceutical Research Library to determine user satisfaction with the graphical user interface-based (GUI) Dynix Marquis compared with the text-based Dynix Classic Online Public Access Catalog (OPAC). Results show that the GUI-based OPAC was preferred by endusers over the text-based OPAC. (eight references) (DGM)

  12. Staradmin -- Starlink User Database Maintainer

    NASA Astrophysics Data System (ADS)

    Fish, Adrian

    The subject of this SSN is a utility called STARADMIN. This utility allows the system administrator to build and maintain a Starlink User Database (UDB). The principal source of information for each user is a text file, named after their username. The content of each file is a list consisting of one keyword followed by the relevant user data per line. These user database files reside in a single directory. The STARADMIN program is used to manipulate these user data files and automatically generate user summary lists.

  13. Computing Lives And Reliabilities Of Turboprop Transmissions

    NASA Technical Reports Server (NTRS)

    Coy, J. J.; Savage, M.; Radil, K. C.; Lewicki, D. G.

    1991-01-01

    Computer program PSHFT calculates lifetimes of variety of aircraft transmissions. Consists of main program, series of subroutines applying to specific configurations, generic subroutines for analysis of properties of components, subroutines for analysis of system, and common block. Main program selects routines used in analysis and causes them to operate in desired sequence. Series of configuration-specific subroutines put in configuration data, perform force and life analyses for components (with help of generic component-property-analysis subroutines), fill property array, call up system-analysis routines, and finally print out results of analysis for system and components. Written in FORTRAN 77(IV).

  14. Construct User Guide

    DTIC Science & Technology

    2012-11-01

    validation using calibrated grounding. In 2007 BRIMS Conference Proceedings, Norfolk, VA. Simon, H. A. (1957). Administrative Behavior: A study of...Construct will write the output to the directory specified by the path name. Users should ensure that if they have opened any output files (e.g., in Excel... open an input file, it will exit and close. There are times when an error message is not present to the user in this situation! Users should ensure

  15. VIRTUAL FRAME BUFFER INTERFACE

    NASA Technical Reports Server (NTRS)

    Wolfe, T. L.

    1994-01-01

    Large image processing systems use multiple frame buffers with differing architectures and vendor supplied user interfaces. This variety of architectures and interfaces creates software development, maintenance, and portability problems for application programs. The Virtual Frame Buffer Interface program makes all frame buffers appear as a generic frame buffer with a specified set of characteristics, allowing programmers to write code which will run unmodified on all supported hardware. The Virtual Frame Buffer Interface converts generic commands to actual device commands. The virtual frame buffer consists of a definition of capabilities and FORTRAN subroutines that are called by application programs. The virtual frame buffer routines may be treated as subroutines, logical functions, or integer functions by the application program. Routines are included that allocate and manage hardware resources such as frame buffers, monitors, video switches, trackballs, tablets and joysticks; access image memory planes; and perform alphanumeric font or text generation. The subroutines for the various "real" frame buffers are in separate VAX/VMS shared libraries allowing modification, correction or enhancement of the virtual interface without affecting application programs. The Virtual Frame Buffer Interface program was developed in FORTRAN 77 for a DEC VAX 11/780 or a DEC VAX 11/750 under VMS 4.X. It supports ADAGE IK3000, DEANZA IP8500, Low Resolution RAMTEK 9460, and High Resolution RAMTEK 9460 Frame Buffers. It has a central memory requirement of approximately 150K. This program was developed in 1985.

  16. User Data Spectrum Theory: Collecting, Interpreting, and Implementing User Data in Organizations

    ERIC Educational Resources Information Center

    Peer, Andrea Jo

    2017-01-01

    Organizations interested in increasing their user experience (UX) capacity lack the tools they need to know how to do so. This dissertation addresses this challenge via three major research efforts: 1) the creation of User Data Spectrum theory and a User Data Spectrum survey for helping organizations better invest resources to grow their UX…

  17. Service user involvement in cancer care: the impact on service users

    PubMed Central

    Cotterell, Phil; Harlow, Gwen; Morris, Carolyn; Beresford, Peter; Hanley, Bec; Sargeant, Anita; Sitzia, John; Staley, Kristina

    2011-01-01

    Abstract Background  Service user involvement is embedded in the United Kingdom’s National Health Service, but knowledge about the impact of involvement on service users, such as the benefits and challenges of involvement, is scant. Our research addresses this gap. Objective  To explore the personal impact of involvement on the lives of service users affected by cancer. Design  We conducted eight focus groups with user groups supplemented by nine face‐to‐face interviews with involved individuals active at a local, regional and national level. Thematic analysis was conducted both independently and collectively. Setting and participants  Sixty‐four participants, engaged in involvement activities in cancer services, palliative care and research, were recruited across Great Britain. Results  We identified three main themes: (i) ‘Expectations and motivations for involvement’– the desire to improve services and the need for user groups to have a clear purpose, (ii) ‘Positive aspects of involvement’– support provided by user groups and assistance to live well with cancer and (iii) ‘Challenging aspects of involvement’– insensitivities and undervaluing of involvement by staff. Conclusions  This study identified that involvement has the capacity to produce varied and significant personal impacts for involved people. Involvement can be planned and implemented in ways that increase these impacts and that mediates challenges for those involved. Key aspects to increase positive impact for service users include the value service providers attach to involvement activities, the centrality with which involvement is embedded in providers’ activities, and the capacity of involvement to influence policy, planning, service delivery, research and/or practice. PMID:21029279

  18. User Antennas

    NASA Technical Reports Server (NTRS)

    Jamnejad, Vahraz; Cramer, Paul

    1990-01-01

    The following subject areas are covered: (1) impact of frequency change of user and spacecraft antenna gain and size; (2) basic personal terminal antennas (impact of 20/30 GHz frequency separation; parametric studies - gain, size, weight; gain and figure of merit (G/T); design data for selected antenna concepts; critical technologies and development goals; and recommendations); and (3) user antenna radiation safety concerns.

  19. VizieR Online Data Catalog: Radiative forces for stellar envelopes (Seaton, 1997)

    NASA Astrophysics Data System (ADS)

    Seaton, M. J.; Yan, Y.; Mihalas, D.; Pradhan, A. K.

    2000-02-01

    (1) Primary data files, stages.zz These files give data for the calculation of radiative accelerations, GRAD, for elements with nuclear charge zz. Data are available for zz=06, 07, 08, 10, 11, 12, 13, 14, 16, 18, 20, 24, 25, 26 and 28. Calculations are made using data from the Opacity Project (see papers SYMP and IXZ). The data are given for each ionisation stage, j. They are tabulated on a mesh of (T, Ne, CHI) where T is temperature, Ne electron density and CHI is abundance multiplier. The files include data for ionisation fractions, for each (T, Ne). The file contents are described in the paper ACC and as comments in the code add.f (2) Code add.f This reads a file stages.zz and creates a file acc.zz giving radiative accelerations averaged over ionisation stages. The code prompts for names of input and output files. The code, as provided, gives equal weights (as defined in the paper ACC) to all stages. Th weights are set in SUBROUTINE WEIGHTS, which could be changed to give any weights preferred by the user. The dependence of diffusion coefficients on ionisation stage is given by a function ZET, which is defined in SUBROUTINE ZETA. The expressions used for ZET are as given in the paper. The user can change that subroutine if other expressions are preferred. The output file contains values, ZETBAR, of ZET, averaged over ionisation stages. (3) Files acc.zz Radiative accelerations computed using add.f as provided. The user will need to run the code add.f only if it is required to change the subroutines WEIGHTS or ZETA. The contents of the files acc.zz are described in the paper ACC and in comments contained in the code add.f. (4) Code accfit.f This code gives gives radiative accelerations, and some related data, for a stellar model. Methods used to interpolate data to the values of (T, RHO) for the stellar model are based on those used in the code opfit.for (see the paper OPF). The executable file accfit.com runs accfit.f. It uses a list of files given in accfit

  20. NASCAP user's manual, 1978

    NASA Technical Reports Server (NTRS)

    Cassidy, J. J., III

    1978-01-01

    NASCAP simulates the charging process for a complex object in either tenuous plasma (geosynchronous orbit) or ground test (electron gun source) environment. Program control words, the structure of user input files, and various user options available are described in this computer programmer's user manual.

  1. Dependence and resistance in community mental health care-Negotiations of user participation between staff and users.

    PubMed

    Femdal, I; Knutsen, I R

    2017-10-01

    WHAT IS KNOWN ON THE SUBJECT?: Implementation of user participation is described as a change from a paternalistic healthcare system to ideals of democratization where users' voices are heard in relational interplays with health professionals. The ideological shift involves a transition from welfare dependency and professional control towards more active service-user roles with associated rights and responsibilities. A collaborative relationship between users and professionals in mental health services is seen as important by both parties. Nevertheless, the health professionals find it challenging in practice to reorient their roles and to find productive ways to cooperate. WHAT THIS PAPER ADDS TO EXISTING KNOWLEDGE?: This study illuminates how user participation is negotiated and involves multiple and shifting subject positions in the collaboration between users and professionals in community mental health care. By taking different positions, the relationship between users and professionals develops through dynamic interaction. This study challenges understandings of equality and implicit "truths" in user participation by illuminating subtle forms of power and dilemmas that arise in user-professional negotiations. WHAT ARE THE IMPLICATIONS FOR PRACTICE?: Instead of denying the appearance of power, it is important to question the execution of power in the interplay between users and professionals. Focusing on the negotiation processes between users and professionals is important for increasing reflection on and improving understanding of the dynamic in collaboration and speech. By focusing on negotiations, power can be used in productive ways in user-professional relationships. Introduction Implementation of user participation is considered important in today's mental health care. Research shows, however, that user participation lacks clarity and provokes uncertainty regarding shifting roles. Aim To investigate negotiation of user participation in a microstudy of

  2. Perspectives on User Satisfaction Surveys.

    ERIC Educational Resources Information Center

    Cullen, Rowena

    2001-01-01

    Discusses academic libraries, digital environments, increasing competition, the relationship between service quality and user satisfaction, and user surveys. Describes the SERVQUAL model that measures service quality and user satisfaction in academic libraries; considers gaps between user expectations and managers' perceptions of user…

  3. Flight dynamics analysis and simulation of heavy lift airships. Volume 5: Programmer's manual

    NASA Technical Reports Server (NTRS)

    Ringland, R. F.; Tischler, M. B.; Jex, H. R.; Emmen, R. D.; Ashkenas, I. L.

    1982-01-01

    The Programmer's Manual contains explanations of the logic embodied in the various program modules, a dictionary of program variables, a subroutine listing, subroutine/common block/cross reference listing, and a calling/called subroutine cross reference listing.

  4. Comparison of sensory, physiological, personality, and cultural attributes in regular spicy food users and non-users.

    PubMed

    Ludy, Mary-Jon; Mattes, Richard D

    2012-02-01

    Some individuals savor spicy foods, while others avoid them. Reasons underlying this range of hedonic responses are unknown. The purpose of this study was to explore the basis for individual differences in preference for spicy foods. Regular spicy food users (n=13) and non-users (n=12) were characterized for selected sensory, physiological, personality, and cultural attributes. Individual differences between users and non-users were primarily related to sensory and cultural attributes (i.e., a higher proportion of users reported consuming spicy foods since childhood and users rated spicy foods as more palatable and were better able to discriminate this burn than non-users). Users and non-users exhibited comparable responsiveness to noxious pressure pain, oral tactile sensitivity, and auditory sensitivity, varying only in responsiveness to oral thermal heat (i.e., users were more sensitive to increases than non-users). Studied personality traits did not vary between users and non-users. These findings suggest that prior experience, rather than physiological adaptation or personality differences, may best predict preference for spicy foods. These findings are of public health interest, given that spicy food consumption is reported to confer weight management and food safety benefits. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. Numerical analysis of stiffened shells of revolution. Volume 4: Engineer's program manual for STARS-2S shell theory automated for rotational structures - 2 (statics) digital computer program

    NASA Technical Reports Server (NTRS)

    Svalbonas, V.; Ogilvie, P.

    1973-01-01

    The engineering programming information for the digital computer program for analyzing shell structures is presented. The program is designed to permit small changes such as altering the geometry or a table size to fit the specific requirements. Each major subroutine is discussed and the following subjects are included: (1) subroutine description, (2) pertinent engineering symbols and the FORTRAN coded counterparts, (3) subroutine flow chart, and (4) subroutine FORTRAN listing.

  6. Efficient spares matrix multiplication scheme for the CYBER 203

    NASA Technical Reports Server (NTRS)

    Lambiotte, J. J., Jr.

    1984-01-01

    This work has been directed toward the development of an efficient algorithm for performing this computation on the CYBER-203. The desire to provide software which gives the user the choice between the often conflicting goals of minimizing central processing (CPU) time or storage requirements has led to a diagonal-based algorithm in which one of three types of storage is selected for each diagonal. For each storage type, an initialization sub-routine estimates the CPU and storage requirements based upon results from previously performed numerical experimentation. These requirements are adjusted by weights provided by the user which reflect the relative importance the user places on the resources. The three storage types employed were chosen to be efficient on the CYBER-203 for diagonals which are sparse, moderately sparse, or dense; however, for many densities, no diagonal type is most efficient with respect to both resource requirements. The user-supplied weights dictate the choice.

  7. Are medical marijuana users different from recreational users? The view from primary care.

    PubMed

    Roy-Byrne, Peter; Maynard, Charles; Bumgardner, Kristin; Krupski, Antoinette; Dunn, Chris; West, Imara I; Donovan, Dennis; Atkins, David C; Ries, Richard

    2015-10-01

    Marijuana is currently approved for medical use in 23 states. Both clinicians and the lay public have questioned whether users of marijuana for medical purposes are different from users of marijuana for recreational purposes. This study examined similarities and differences in important clinical characteristics between users of medical marijuana and users of recreational marijuana. The sample consisted of 868 adult primary care patients in Washington State, who reported use of medical marijuana (n = 131), recreational marijuana (n = 525), or drugs other than marijuana (n = 212). Retention was over 87% at 3-, 6-, 9-, and 12-month assessments. The majority of medical, psychiatric, substance use, and service utilization characteristic comparisons were not significant. However, medical marijuana users had significantly more medical problems, a significantly larger proportion reported >15 days medical problems in the past month, and significantly smaller proportions reported no pain and no mobility limitations (p < .001). Medical marijuana users also had significantly lower drug problem severity, lower alcohol problem severity, and significantly larger proportions reported using marijuana alone and concomitant opioid use only (p < .001). There was no significant difference between medical and recreational users in the percentage using marijuana with at least two additional substances (48% vs. 58%, respectively, p = .05). Although our results suggest that there are few distinct differences between medical and recreational users of marijuana, the differences observed, while mostly very small in effect size (<.2), are consistent with at least some medical users employing marijuana to relieve symptoms and distress associated with medical illness. © American Academy of Addiction Psychiatry.

  8. Preliminary ISIS users manual

    NASA Technical Reports Server (NTRS)

    Grantham, C.

    1979-01-01

    The Interactive Software Invocation (ISIS), an interactive data management system, was developed to act as a buffer between the user and host computer system. The user is provided by ISIS with a powerful system for developing software or systems in the interactive environment. The user is protected from the idiosyncracies of the host computer system by providing such a complete range of capabilities that the user should have no need for direct access to the host computer. These capabilities are divided into four areas: desk top calculator, data editor, file manager, and tool invoker.

  9. Technologies for physical activity self-monitoring: a study of differences between users and non-users

    PubMed Central

    Åkerberg, Anna; Söderlund, Anne; Lindén, Maria

    2017-01-01

    Background Different kinds of physical activity (PA) self-monitoring technologies are used today to monitor and motivate PA behavior change. The user focus is essential in the development process of this technology, including potential future users such as representatives from the group of non-users. There is also a need to study whether there are differences between the groups of users and non-users. The aims of this study were to investigate possible differences between users and non-users regarding their opinions about PA self-monitoring technologies and to investigate differences in demographic variables between the groups. Materials and methods Participants were randomly selected from seven municipalities in central Sweden. In total, 107 adults responded to the Physical Activity Products Questionnaire, which consisted of 22 questions. Results Significant differences between the users and non-users were shown for six of the 20 measurement-related items: measures accurately (p=0.007), measures with high precision (p=0.024), measures distance (p=0.020), measures speed (p=0.003), shows minutes of activity (p=0.004), and shows geographical position (p=0.000). Significant differences between the users and non-users were also found for two of the 29 encouragement items: measures accurately (p=0.001) and has long-term memory (p=0.019). Significant differences between the groups were also shown for level of education (p=0.030) and level of physical exercise (p=0.037). Conclusion With a few exceptions, the users and the non-users in this study had similar opinions about PA self-monitoring technologies. Because this study showed significant differences regarding level of education and level of physical exercise, these demographic variables seemed more relevant to investigate than differences in opinions about the PA self-monitoring technologies. PMID:28280399

  10. Software Development for a Satellite Signal Analyzer

    DTIC Science & Technology

    1979-12-01

    uses this mode index. BUTLI3(18,6) 1*4 Is an array of button num- bers used by the subroutine KTLSIM to simulate the user pushing bottons by...either the program SATCOM will be executed, or if HOLD was previously pushed, the array BUTLIS is used to sim- ulate the pushing of the bottons on...in branch 1 to the AW /WSC-3 has to be on. Branches 1-3 provide power to the lab benches, rack 0-6, and uninterruptable power to the time code

  11. An Automated System for the Control of, and Data Acquisition from Multiphoton Ionization and Fluorescence Lifetime Measurements.

    DTIC Science & Technology

    1986-09-01

    Quanta- Ray company , which also supplied the laser used for the multiphoton work. The, burner was mounted on a translator stage from Velmex, Inc...and no longer exists as a process in the system. When the user analysis program has completed, the lifetime program is again automatically re-started...KCHAR) RETURN 100 FORMAT(I3) 101 FORMAT(F7.2) END SUBROUTINE LAB4 FODA SE"oteD C This routine puts the label "INTEGRAL FROM DATA SET" on the MDP C screen

  12. User's manual for FRAC3D: Supplement to report on stress analysis for structures with surface cracks

    NASA Technical Reports Server (NTRS)

    Bell, J. C.; Hopper, A. T.; Hayes, P. A.

    1978-01-01

    The FRAC3D computer program, designed for use in analyzing stresses in structures (including plates, bars, or blocks) which may contain part-circular surface cracks or embedded circular cracks is described. Instructions are provided for preparing input, including that for the supporting programs LATTICE and MATSOL as well as for FRAC3D. The course of a substantial illustrative calculation is shown with both input and output. The formulas underlying the calculations are summarized and related to the subroutines in which they are used. Many issues of strategy in using this program for analysing stresses around surface cracks are elucidated.

  13. Thermo-mechanical Modelling of Pebble Beds in Fusion Blankets and its Implementation by a Return-Mapping Algorithm

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gan, Yixiang; Kamlah, Marc

    In this investigation, a thermo-mechanical model of pebble beds is adopted and developed based on experiments by Dr. Reimann at Forschungszentrum Karlsruhe (FZK). The framework of the present material model is composed of a non-linear elastic law, the Drucker-Prager-Cap theory, and a modified creep law. Furthermore, the volumetric inelastic strain dependent thermal conductivity of beryllium pebble beds is taken into account and full thermo-mechanical coupling is considered. Investigation showed that the Drucker-Prager-Cap model implemented in ABAQUS can not fulfill the requirements of both the prediction of large creep strains and the hardening behaviour caused by creep, which are of importancemore » with respect to the application of pebble beds in fusion blankets. Therefore, UMAT (user defined material's mechanical behaviour) and UMATHT (user defined material's thermal behaviour) routines are used to re-implement the present thermo-mechanical model in ABAQUS. An elastic predictor radial return mapping algorithm is used to solve the non-associated plasticity iteratively, and a proper tangent stiffness matrix is obtained for cost-efficiency in the calculation. An explicit creep mechanism is adopted for the prediction of time-dependent behaviour in order to represent large creep strains in high temperature. Finally, the thermo-mechanical interactions are implemented in a UMATHT routine for the coupled analysis. The oedometric compression tests and creep tests of pebble beds at different temperatures are simulated with the help of the present UMAT and UMATHT routines, and the comparison between the simulation and the experiments is made. (authors)« less

  14. From the Users' Perspective-The UCSD Libraries User Survey Project.

    ERIC Educational Resources Information Center

    Talbot, Dawn E.; Lowell, Gerald R.; Martin, Kerry

    1998-01-01

    Discussion of a user-driven survey conducted at the University of California, San Diego libraries focuses on the methodology that resulted in a high response rate. Highlights goals for the survey, including acceptance of data by groups outside the library and for benchmarking data; planning; user population; and questionnaire development. (LRW)

  15. New Users | Center for Cancer Research

    Cancer.gov

    New Users Becoming a Core Facilities User The following steps are applicable to anyone who would like to become a user of the CCR SAXS Core facilities. All users are required to follow the Core Facilty User Polices.

  16. 7 CFR 29.425 - Submission and disposition of pesticide residues and end user(s) certification.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false Submission and disposition of pesticide residues and... Miscellaneous § 29.425 Submission and disposition of pesticide residues and end user(s) certification. (a) Completion of certification: The importer shall complete a pesticide residue and end user(s) certification on...

  17. 7 CFR 29.425 - Submission and disposition of pesticide residues and end user(s) certification.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Submission and disposition of pesticide residues and... Miscellaneous § 29.425 Submission and disposition of pesticide residues and end user(s) certification. (a) Completion of certification: The importer shall complete a pesticide residue and end user(s) certification on...

  18. 7 CFR 29.425 - Submission and disposition of pesticide residues and end user(s) certification.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Submission and disposition of pesticide residues and... Miscellaneous § 29.425 Submission and disposition of pesticide residues and end user(s) certification. (a) Completion of certification: The importer shall complete a pesticide residue and end user(s) certification on...

  19. 7 CFR 29.425 - Submission and disposition of pesticide residues and end user(s) certification.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Submission and disposition of pesticide residues and... Miscellaneous § 29.425 Submission and disposition of pesticide residues and end user(s) certification. (a) Completion of certification: The importer shall complete a pesticide residue and end user(s) certification on...

  20. User Preferences in Image Map Using

    NASA Astrophysics Data System (ADS)

    Vondráková, A.; Vozenilek, V.

    2016-06-01

    In the process of map making, the attention is given to the resulting image map (to be accurate, readable, and suit the primary purpose) and its user aspects. Current cartography understands the user issues as all matters relating to user perception, map use and also user preferences. Most commercial cartographic production is strongly connected to economic circumstances. Companies are discovering user's interests and market demands. However, is it sufficient to focus just on the user's preferences? Recent research on user aspects at Palacký University Olomouc addresses a much wider scope of user aspects. The user's preferences are very often distorting - the users think that the particular image map is kind, beautiful, and useful and they wants to buy it (or use it - it depends on the form of the map production). But when the same user gets the task to use practically this particular map (such as finding the shortest way), so the user concludes that initially preferred map is useless, and uses a map, that was worse evaluated according to his preferences. It is, therefore, necessary to evaluate not only the correctness of image maps and their aesthetics but also to assess the user perception and other user issues. For the accomplishment of such testing, eye-tracking technology is a useful tool. The research analysed how users read image maps, or if they prefer image maps over traditional maps. The eye tracking experiment on the comparison of the conventional and image map reading was conducted. The map readers were asked to solve few simple tasks with either conventional or image map. The readers' choice of the map to solve the task was one of investigated aspect of user preferences. Results demonstrate that the user preferences and user needs are often quite different issues. The research outcomes show that it is crucial to implement map user testing into the cartographic production process.

  1. User acquaintance with mobile interfaces.

    PubMed

    Ehrler, Frederic; Walesa, Magali; Sarrey, Evelyne; Wipfli, Rolf; Lovis, Christian

    2013-01-01

    Handheld technology finds slowly its place in the healthcare world. Some clinicians already use intensively dedicated mobile applications to consult clinical references. However, handheld technology hasn't still broadly embraced to the core of the healthcare business, the hospitals. The weak penetration of handheld technology in the hospitals can be partly explained by the caution of stakeholders that must be convinced about the efficiency of these tools before going forward. In a domain where temporal constraints are increasingly strong, caregivers cannot loose time on playing with gadgets. All users are not comfortable with tactile manipulations and the lack of dedicated peripheral complicates entering data for novices. Stakeholders must be convinced that caregivers will be able to master handheld devices. In this paper, we make the assumption that the proper design of an interface may influence users' performances to record information. We are also interested to find out whether users increase their efficiency when using handheld tools repeatedly. To answer these questions, we have set up a field study to compare users' performances on three different user interfaces while recording vital signs. Some user interfaces were familiar to users, and others were totally innovative. Results showed that users' familiarity with smartphone influences their performances and that users improve their performances by repeating a task.

  2. NMCS Information Processing System 360 Formatted File System (NIPS 360 FFS). Users Manual. Volume 1. Introduction to File Concepts

    DTIC Science & Technology

    1978-09-01

    input source language (other than ?S). Used in double form, negates an FFT spcification for a subroutine. / (Slash) Used to separate numeric digits (V-l...1) represents the digits 1-999 and also digits followed by a letter, e.g., LINE1OA ’. Th, E311owing name prefiKes are not allowed: PSSQ, VSEr, VSZ...b ZERO OUT 6 LA 6,12 (6) ADD 12 TO 6 PUT IN REG b 4’MOVF INPUT DATE rC WORK APEA, REFORMAT DD AND YY 0C)NVERr TWO DIGIT MONTH TO SYMBOLIC THREE

  3. Examining Marijuana User and Non-User Prototypes in Formative Research for Prevention Campaigns

    ERIC Educational Resources Information Center

    Comello, Maria Leonora G.; Slater, Michael D.

    2010-01-01

    We report on research--both quantitative and qualitative--conducted to explore perceptions of prototypes of marijuana users, as well as the extent to which self-prototype congruence predicted marijuana use intention. Results of a survey of undergraduates (N = 139) showed that prototypes of users and non-users differed in terms of key attributes,…

  4. Gender differences in self-reported anxiety, depression, and somatization among ecstasy/MDMA polydrug users, alcohol/tobacco users, and nondrug users.

    PubMed

    Milani, Raffaella M; Parrott, Andy C; Turner, John J D; Fox, Helen C

    2004-07-01

    Previous research has found gender differences in both psychological and physiological responses to drugs. The present investigation explores gender variability in patterns of drug use in relation to self-reported depression, anxiety, and somatization. The current study confirms that heavy illegal drug users are represented by a preponderance of males than females. However, within each drug group category, females generally reported higher psychopathology scores than males. This was significant for all three subscales in the alcohol/tobacco group, for depression scores in the alcohol/tobacco, cannabis/alcohol, and light Ecstasy users group, and for depression scores for the alcohol group. Interestingly, in the male sample, drug users reported higher symptom ratings than nondrug users, whereas women's scores remained constant across drug groups. Copyright 2004 Elsevier Ltd.

  5. Helping Users Help Themselves.

    ERIC Educational Resources Information Center

    O'Malley, Claire E.

    This discussion of the design of user-initiated help systems in computers focuses on the information that users actively seek to help them with their tasks, with emphasis on how to help users ask the questions that will bridge the gap between the initial internal (mental) form of the query and their information need as expressed by the system.…

  6. FEAMAC/CARES Stochastic-Strength-Based Damage Simulation Tool for Ceramic Matrix Composites

    NASA Technical Reports Server (NTRS)

    Nemeth, Noel; Bednarcyk, Brett; Pineda, Evan; Arnold, Steven; Mital, Subodh; Murthy, Pappu; Bhatt, Ramakrishna

    2016-01-01

    Reported here is a coupling of two NASA developed codes: CARES (Ceramics Analysis and Reliability Evaluation of Structures) with the MAC/GMC (Micromechanics Analysis Code/ Generalized Method of Cells) composite material analysis code. The resulting code is called FEAMAC/CARES and is constructed as an Abaqus finite element analysis UMAT (user defined material). Here we describe the FEAMAC/CARES code and an example problem (taken from the open literature) of a laminated CMC in off-axis loading is shown. FEAMAC/CARES performs stochastic-strength-based damage simulation response of a CMC under multiaxial loading using elastic stiffness reduction of the failed elements.

  7. Stochastic-Strength-Based Damage Simulation Tool for Ceramic Matrix Composite

    NASA Technical Reports Server (NTRS)

    Nemeth, Noel; Bednarcyk, Brett; Pineda, Evan; Arnold, Steven; Mital, Subodh; Murthy, Pappu

    2015-01-01

    Reported here is a coupling of two NASA developed codes: CARES (Ceramics Analysis and Reliability Evaluation of Structures) with the MAC/GMC (Micromechanics Analysis Code/ Generalized Method of Cells) composite material analysis code. The resulting code is called FEAMAC/CARES and is constructed as an Abaqus finite element analysis UMAT (user defined material). Here we describe the FEAMAC/CARES code and an example problem (taken from the open literature) of a laminated CMC in off-axis loading is shown. FEAMAC/CARES performs stochastic-strength-based damage simulation response of a CMC under multiaxial loading using elastic stiffness reduction of the failed elements.

  8. User-generated online health content: a survey of Internet users in the United Kingdom.

    PubMed

    O'Neill, Braden; Ziebland, Sue; Valderas, Jose; Lupiáñez-Villanueva, Francisco

    2014-04-30

    The production of health information has begun to shift from commercial organizations to health care users themselves. People increasingly go online to share their own health and illness experiences and to access information others have posted, but this behavior has not been investigated at a population level in the United Kingdom. This study aims to explore access and production of user-generated health content among UK Internet users and to investigate relationships between frequency of use and other variables. We undertook an online survey of 1000 UK Internet users. Descriptive and multivariate statistical analyses were used to interpret the data. Nearly one-quarter of respondents (23.7%, 237/1000) reported accessing and sharing user-generated health content online, whereas more than 20% (22.2%, 222/1000) were unaware that it was possible to do this. Respondents could be divided into 3 groups based on frequency of use: rare users (78.7%, 612/778) who accessed and shared content less than weekly, users (13.9%, 108/778) who did so weekly, and superusers (7.5%, 58/778) who did so on a daily basis. Superusers were more likely to be male (P<.001) and to be employed (P<.001), but there were no differences between the groups with respect to educational level (P=.99) or health status (P=.63). They were more likely to use the Internet for varied purposes such as banking and shopping (P<.001). Although this study found reasonably widespread access of user-generated online health content, only a minority of respondents reported doing so frequently. As this type of content proliferates, superusers are likely to shape the health information that others access. Further research should assess the effect of user-generated online content on health outcomes and use of health services by Internet users.

  9. User-Generated Online Health Content: A Survey of Internet Users in the United Kingdom

    PubMed Central

    Ziebland, Sue; Valderas, Jose; Lupiáñez-Villanueva, Francisco

    2014-01-01

    Background The production of health information has begun to shift from commercial organizations to health care users themselves. People increasingly go online to share their own health and illness experiences and to access information others have posted, but this behavior has not been investigated at a population level in the United Kingdom. Objective This study aims to explore access and production of user-generated health content among UK Internet users and to investigate relationships between frequency of use and other variables. Methods We undertook an online survey of 1000 UK Internet users. Descriptive and multivariate statistical analyses were used to interpret the data. Results Nearly one-quarter of respondents (23.7%, 237/1000) reported accessing and sharing user-generated health content online, whereas more than 20% (22.2%, 222/1000) were unaware that it was possible to do this. Respondents could be divided into 3 groups based on frequency of use: rare users (78.7%, 612/778) who accessed and shared content less than weekly, users (13.9%, 108/778) who did so weekly, and superusers (7.5%, 58/778) who did so on a daily basis. Superusers were more likely to be male (P<.001) and to be employed (P<.001), but there were no differences between the groups with respect to educational level (P=.99) or health status (P=.63). They were more likely to use the Internet for varied purposes such as banking and shopping (P<.001). Conclusions Although this study found reasonably widespread access of user-generated online health content, only a minority of respondents reported doing so frequently. As this type of content proliferates, superusers are likely to shape the health information that others access. Further research should assess the effect of user-generated online content on health outcomes and use of health services by Internet users. PMID:24784798

  10. The PANTHER User Experience

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Coram, Jamie L.; Morrow, James D.; Perkins, David Nikolaus

    2015-09-01

    This document describes the PANTHER R&D Application, a proof-of-concept user interface application developed under the PANTHER Grand Challenge LDRD. The purpose of the application is to explore interaction models for graph analytics, drive algorithmic improvements from an end-user point of view, and support demonstration of PANTHER technologies to potential customers. The R&D Application implements a graph-centric interaction model that exposes analysts to the algorithms contained within the GeoGraphy graph analytics library. Users define geospatial-temporal semantic graph queries by constructing search templates based on nodes, edges, and the constraints among them. Users then analyze the results of the queries using bothmore » geo-spatial and temporal visualizations. Development of this application has made user experience an explicit driver for project and algorithmic level decisions that will affect how analysts one day make use of PANTHER technologies.« less

  11. FRED user's manual

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Shilling, J.

    1984-02-01

    FRED, the friendly editor, is a screen-based structured editor. This manual is intended to serve the needs of a wide range of users of the FRED text editor. Most users will find it sufficient to read the introductory material in section 2, supplemented with the full command set description in section 3. Advanced users may wish to change the keystroke sequences which invoke editor commands. Section 4 describes how to change key bindings and how to define command macros. Some users may need to modify a language description or create an entirely new language description for use with FRED. Sectionmore » 5 describes the format of the language descriptions used by the editor, and describes how to construct a language grammar. Section 6 describes known portability problems of the FRED editor and should concern only system installation personnel. The editor points out syntax errors in the file being edited and does automatic pretty printing.« less

  12. An improved biometrics-based remote user authentication scheme with user anonymity.

    PubMed

    Khan, Muhammad Khurram; Kumari, Saru

    2013-01-01

    The authors review the biometrics-based user authentication scheme proposed by An in 2012. The authors show that there exist loopholes in the scheme which are detrimental for its security. Therefore the authors propose an improved scheme eradicating the flaws of An's scheme. Then a detailed security analysis of the proposed scheme is presented followed by its efficiency comparison. The proposed scheme not only withstands security problems found in An's scheme but also provides some extra features with mere addition of only two hash operations. The proposed scheme allows user to freely change his password and also provides user anonymity with untraceability.

  13. User's manual for MacPASCO

    NASA Technical Reports Server (NTRS)

    Lucas, S. H.; Davis, R. C.

    1992-01-01

    A user's manual is presented for MacPASCO, which is an interactive, graphic, preprocessor for panel design. MacPASCO creates input for PASCO, an existing computer code for structural analysis and sizing of longitudinally stiffened composite panels. MacPASCO provides a graphical user interface which simplifies the specification of panel geometry and reduces user input errors. The user draws the initial structural geometry and reduces user input errors. The user draws the initial structural geometry on the computer screen, then uses a combination of graphic and text inputs to: refine the structural geometry; specify information required for analysis such as panel load and boundary conditions; and define design variables and constraints for minimum mass optimization. Only the use of MacPASCO is described, since the use of PASCO has been documented elsewhere.

  14. Perceptions of parental bonding in freebase cocaine users versus non-illicit drug users

    PubMed Central

    Pettenon, Márcia; Kessler, Felix Henrique Paim; Guimarães, Luciano S. P.; Pedroso, Rosemeri Siqueira; Hauck, Simone; Pechansky, Flavio

    2014-01-01

    Background & objectives: Evidence has suggested that parenting styles have peculiar characteristics in families with drug-related issues. This study was undertaken to investigate the perception of crack (smoke cocaine) users and non-users about parental bonding quality regarding care and control in Brazil. Methods: A total of 198 hospitalized crack users and 104 users of any non-illicit drug were assessed using the Parental Bonding Instrument (PBI), the sixth version of the Addiction Severity Index (ASI) and Mini International Neuropsychiatric Interview (MINI). Results: Adjusted logistic regression analysis showed that crack users were more likely (ORadj = 9.68; 95% CI: 2.82, 33.20) to perceive neglectful mothers, as well as more likely (ORadj = 4.71, 95% CI: 2.17, 10.22) to perceive controlling and affectionless fathers in comparison with non-illicit drug users who were more likely to perceive optimal parenting. Interpretation & conclusions: Our findings indicate that the perception of neglectful mothers and affectionless controlling fathers may be associated with the tendency of the children to be less resilient when facing stressful events, leading them to a greater risk to use crack. PMID:25109717

  15. The GPRIME approach to finite element modeling

    NASA Technical Reports Server (NTRS)

    Wallace, D. R.; Mckee, J. H.; Hurwitz, M. M.

    1983-01-01

    GPRIME, an interactive modeling system, runs on the CDC 6000 computers and the DEC VAX 11/780 minicomputer. This system includes three components: (1) GPRIME, a user friendly geometric language and a processor to translate that language into geometric entities, (2) GGEN, an interactive data generator for 2-D models; and (3) SOLIDGEN, a 3-D solid modeling program. Each component has a computer user interface of an extensive command set. All of these programs make use of a comprehensive B-spline mathematics subroutine library, which can be used for a wide variety of interpolation problems and other geometric calculations. Many other user aids, such as automatic saving of the geometric and finite element data bases and hidden line removal, are available. This interactive finite element modeling capability can produce a complete finite element model, producing an output file of grid and element data.

  16. Utilization Possibilities of Area Definition in User Space for User-Centric Pervasive-Adaptive Systems

    NASA Astrophysics Data System (ADS)

    Krejcar, Ondrej

    The ability to let a mobile device determine its location in an indoor environment supports the creation of a new range of mobile information system applications. The goal of my project is to complement the data networking capabilities of RF wireless LANs with accurate user location and tracking capabilities for user needed data prebuffering. I created a location based system enhancement for locating and tracking users of indoor information system. User position is used for data prebuffering and pushing information from a server to his mobile client. All server data is saved as artifacts (together) with its indoor position information. The area definition for artifacts selecting is described for current and predicted user position along with valuating options for artifacts ranging. Future trends are also discussed.

  17. STS pilot user development program

    NASA Technical Reports Server (NTRS)

    Mcdowell, J. R.

    1977-01-01

    Full exploitation of the STS capabilities will be not only dependent on the extensive use of the STS for known space applications and research, but also on new, innovative ideas of use originating with both current and new users. In recognition of this, NASA has been engaged in a User Development Program for the STS. The program began with four small studies. Each study addressed a separate sector of potential new users to identify techniques and methodologies for user development. The collective results established that a user development function was not only feasible, but necessary for NASA to realize the full potential of the STS. This final report begins with a description of the overall pilot program plan, which involved five specific tasks defined in the contract Statement of Work. Each task is then discussed separately; but two subjects, the development of principal investigators and space processing users, are discussed separately for improved continuity of thought. These discussions are followed by a summary of the primary results and conclusions of the Pilot User Development Program. Specific recommendations of the study are given.

  18. Aztec user`s guide. Version 1

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hutchinson, S.A.; Shadid, J.N.; Tuminaro, R.S.

    1995-10-01

    Aztec is an iterative library that greatly simplifies the parallelization process when solving the linear systems of equations Ax = b where A is a user supplied n x n sparse matrix, b is a user supplied vector of length n and x is a vector of length n to be computed. Aztec is intended as a software tool for users who want to avoid cumbersome parallel programming details but who have large sparse linear systems which require an efficiently utilized parallel processing system. A collection of data transformation tools are provided that allow for easy creation of distributed sparsemore » unstructured matrices for parallel solution. Once the distributed matrix is created, computation can be performed on any of the parallel machines running Aztec: nCUBE 2, IBM SP2 and Intel Paragon, MPI platforms as well as standard serial and vector platforms. Aztec includes a number of Krylov iterative methods such as conjugate gradient (CG), generalized minimum residual (GMRES) and stabilized biconjugate gradient (BICGSTAB) to solve systems of equations. These Krylov methods are used in conjunction with various preconditioners such as polynomial or domain decomposition methods using LU or incomplete LU factorizations within subdomains. Although the matrix A can be general, the package has been designed for matrices arising from the approximation of partial differential equations (PDEs). In particular, the Aztec package is oriented toward systems arising from PDE applications.« less

  19. Quality user support: Supporting quality users

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Woolley, T.C.

    1994-12-31

    During the past decade, fundamental changes have occurred in technical computing in the oil industry. Technical computing systems have moved from local, fragmented quantity, to global, integrated, quality. The compute power available to the average geoscientist at his desktop has grown exponentially. Technical computing applications have increased in integration and complexity. At the same time, there has been a significant change in the work force due to the pressures of restructuring, and the increased focus on international opportunities. The profile of the user of technical computing resources has changed. Users are generally more mature, knowledgeable, and team oriented than theirmore » predecessors. In the 1990s, computer literacy is a requirement. This paper describes the steps taken by Oryx Energy Company to address the problems and opportunities created by the explosive growth in computing power and needs, coupled with the contraction of the business. A successful user support strategy will be described. Characteristics of the program include: (1) Client driven support; (2) Empowerment of highly skilled professionals to fill the support role; (3) Routine and ongoing modification to the support plan; (4) Utilization of the support assignment to create highly trained advocates on the line; (5) Integration of the support role to the reservoir management team. Results of the plan include a highly trained work force, stakeholder teams that include support personnel, and global support from a centralized support organization.« less

  20. Evaluation of Rankine cycle air conditioning system hardware by computer simulation

    NASA Technical Reports Server (NTRS)

    Healey, H. M.; Clark, D.

    1978-01-01

    A computer program for simulating the performance of a variety of solar powered Rankine cycle air conditioning system components (RCACS) has been developed. The computer program models actual equipment by developing performance maps from manufacturers data and is capable of simulating off-design operation of the RCACS components. The program designed to be a subroutine of the Marshall Space Flight Center (MSFC) Solar Energy System Analysis Computer Program 'SOLRAD', is a complete package suitable for use by an occasional computer user in developing performance maps of heating, ventilation and air conditioning components.

  1. Moments of inclination error distribution computer program

    NASA Technical Reports Server (NTRS)

    Myler, T. R.

    1981-01-01

    A FORTRAN coded computer program is described which calculates orbital inclination error statistics using a closed-form solution. This solution uses a data base of trajectory errors from actual flights to predict the orbital inclination error statistics. The Scott flight history data base consists of orbit insertion errors in the trajectory parameters - altitude, velocity, flight path angle, flight azimuth, latitude and longitude. The methods used to generate the error statistics are of general interest since they have other applications. Program theory, user instructions, output definitions, subroutine descriptions and detailed FORTRAN coding information are included.

  2. An Improved Biometrics-Based Remote User Authentication Scheme with User Anonymity

    PubMed Central

    Kumari, Saru

    2013-01-01

    The authors review the biometrics-based user authentication scheme proposed by An in 2012. The authors show that there exist loopholes in the scheme which are detrimental for its security. Therefore the authors propose an improved scheme eradicating the flaws of An's scheme. Then a detailed security analysis of the proposed scheme is presented followed by its efficiency comparison. The proposed scheme not only withstands security problems found in An's scheme but also provides some extra features with mere addition of only two hash operations. The proposed scheme allows user to freely change his password and also provides user anonymity with untraceability. PMID:24350272

  3. LIMS user acceptance testing.

    PubMed

    Klein, Corbett S

    2003-01-01

    Laboratory Information Management Systems (LIMS) play a key role in the pharmaceutical industry. Thorough and accurate validation of such systems is critical and is a regulatory requirement. LIMS user acceptance testing is one aspect of this testing and enables the user to make a decision to accept or reject implementation of the system. This paper discusses key elements in facilitating the development and execution of a LIMS User Acceptance Test Plan (UATP).

  4. Aircraft Hydraulic Systems Dynamic Analysis

    DTIC Science & Technology

    1977-10-01

    WHEQUT) for a Quincke tube resonator was revised. A similar subroutine was developed to simulate a hydraulic syscem acoustic filter available commer...input datt’l. Tlhe’ .il l t ’p. ol ý", nel-, r , ’li l t io (11 WAý: alq I SO ij•jI Ld t 0 t l• 11 ’ W11 I’ ( Quincke tube) subroutine. With these...studying pump hanger torque, precompression, decompression WHEQUT Subroutine 1) Revised, made corrections to, and ran Quincke tube subroutine (WHEQUT) b

  5. Enabling User Preferences Through Data Exchange

    DOT National Transportation Integrated Search

    1997-08-01

    This paper describes a process, via user- air traffic management (ATM) data : exchange, for enabling user preferences in an ATM-based system. User : preferences may be defined in terms of a four-dimensional (4D) user-preferred : trajectory, or a seri...

  6. Thermal-mechanical modeling of laser ablation hybrid machining

    NASA Astrophysics Data System (ADS)

    Matin, Mohammad Kaiser

    2001-08-01

    materials and contact between workpiece and tool. The theoretical formulation associated with LAHM for solving the thermal-mechanical problem using the finite element method is presented. The thermal formulation is incorporated in the user defined subroutines called by ABAQUS/Standard. The mechanical portion is modeled using ABAQUS/Explicit's general capabilities of modeling interactions involving contact and separation. The results obtained from the FEA simulations showed that the cutting force decrease considerably in both LAEM Surface Absorption (LARM-SA) and LAHM volume absorption (LAHM-VA) models relative to LAM model. It was observed that the HAZ can be expanded or narrowed depending on the laser speed and power. The cutting force is minimal at the last extent of the HAZ. In both the models the laser ablates material thus reducing material stiffness as well as relaxing the thermal stress. The stress values obtained showed compressive yield stress just below the ablated surface and chip. The failure occurs by conventional cutting where tensile stress exceeds the tensile strength of the material at that temperature. In this hybrid machining process the advantages of both the individual machining processes were realized.

  7. Becoming a medical marijuana user.

    PubMed

    Lankenau, Stephen E; Kioumarsi, Avat; Reed, Megan; McNeeley, Miles; Iverson, Ellen; Wong, Carolyn F

    2018-02-01

    Since marijuana became legal for medical use in California in 1996, reasons for medical use among medical marijuana patients (MMP) have become increasingly well described in qualitative studies. However, few studies have detailed how the use of marijuana for medical purposes fits into the broader career trajectories of either becoming a marijuana user or becoming a MMP, including the social influences on medical use. Young adult MMP (N=40) aged 18 to 26 years old were recruited in Los Angeles, CA in 2014-15 and administered a semi-structured interview that included questions focusing on marijuana use practices before and after becoming MMP. MMP were categorized into three trajectory groups: primarily medical users (n=30); primarily non-medical users (n=3); and medical users who transitioned to non-medical users (n=7). Most medical users discovered medicinal effects from marijuana in the context of non-medical use as adolescents prior to becoming MMP. Becoming a mature MMP followed interactions with dispensary staff or further self-exploration of medical uses and often involved a social process that helped confirm the legitimacy of medical use and identity as a medical user. In some cases, MMP transitioned back to non-medical users as health conditions improved or remained primarily non-medical users even after becoming MMP for reasons unrelated to health, e.g., protection against arrest. Becoming a medical marijuana user was an important career trajectory that was influenced by early discoveries of effective medicinal use, interaction with proponents of medical use at dispensaries, experiences with new kinds of medical use, and the demands of particular health condition requiring more or less treatment with marijuana. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Internet-Users and Internet Non-Users Attitude towards Research: A Comparative Study on Post-Graduate Students

    ERIC Educational Resources Information Center

    Noor ul Amin, Syed

    2017-01-01

    The purpose of the present study was to compare the Internet-user and Internet Non-user post-graduate students on their attitude towards research. The sample comprised 600 post graduate students (300 Internet-users and 300 Internet-Non-users) drawn from different faculties of University of Kashmir (J&K), India. Random sampling technique was…

  9. The TIMS Data User's Workshop

    NASA Technical Reports Server (NTRS)

    Kahle, Anne B. (Editor); Abbott, Elsa (Editor)

    1986-01-01

    A workshop was held to bring together all users of data from NASA's airborne Thermal Infrared Multispectral Scanner (TIMS). The purpose was to allow users to compare results, data processing algorithms, and problems encountered; to update the users on the latest instrument changes and idiosyncracies, including distribution of the TIMS investigation guide; to inform the users of the wide range of problems that are currently being tackled by other TIMS investigators; to explore ways to expand the user community; to discuss current areas where more basic research is required; and to discuss the future directions of NASA's thermal infrared remote sensing programs. Also discussed were: geology, land use, archeology; and data processing and noise research.

  10. Quality in End User Documentation.

    ERIC Educational Resources Information Center

    Morrison, Ronald

    1994-01-01

    Discusses quality in end-user documentation for computer applications and explains four approaches to improving quality in end-user documents. Highlights include online help, usability testing, technical writing elements, statistical approaches, and concepts relating to software quality that are also applicable to user manuals. (LRW)

  11. Disk Operating System User's Guide

    DOT National Transportation Integrated Search

    1972-05-01

    This document serves the purpose of bringing together in one place most of the information a user needs to use the DDP-516 Disk Operating System, (DOS). DOS is a core resident, one user, console-oriented operating system which allows the user to cont...

  12. A survey of users and non-users of a UK teaching hospital library and information service.

    PubMed

    Turtle, Kathleen M

    2005-12-01

    The Lancashire Teaching Hospitals NHS Trust was formed in 2002 with the merger of two existing trusts. The library services unified to create a new expanded service with 11 staff. The librarians wanted to test out users' opinions of the service, as a basis for a developmental strategy. They also wanted to find out to what extent they were offering a multi-disciplinary service, available to all staff. Therefore it was decided to include both users and non-users in the survey. A twenty-question questionnaire was sent out to a 10% sample of registered users in all staff categories. The same questionnaire was sent out to a 10% sample of non-users, with the help of the Human Resources Department. The library staff and facilities were generally well regarded. The stock needed expansion in various areas, especially allied health and biomedical science. Non-users were in fact often occasional or remote users. Other non-users needed informing that they were entitled to use the service. Further research is required, especially concerning the information needs of allied health and scientific staff. There is a need for stock expansion. A marketing strategy is required to capture the interest of potential users.

  13. 3DGRAPE/AL User's Manual

    NASA Technical Reports Server (NTRS)

    Sorenson, Reese L.; Alter, Stephen J.

    1995-01-01

    This document is a users' manual for a new three-dimensional structured multiple-block volume g generator called 3DGRAPE/AL. It is a significantly improved version of the previously-released a widely-distributed programs 3DGRAPE and 3DMAGGS. It generates volume grids by iteratively solving the Poisson Equations in three-dimensions. The right-hand-side terms are designed so that user-specific; grid cell heights and user-specified grid cell skewness near boundary surfaces result automatically, with little user intervention. The code is written in Fortran-77, and can be installed with or without a simple graphical user interface which allows the user to watch as the grid is generated. An introduction describing the improvements over the antecedent 3DGRAPE code is presented first. Then follows a chapter on the basic grid generator program itself, and comments on installing it. The input is then described in detail. After that is a description of the Graphical User Interface. Five example cases are shown next, with plots of the results. Following that is a chapter on two input filters which allow use of input data generated elsewhere. Last is a treatment of the theory embodied in the code.

  14. Frequent users of rural primary care: comparisons with randomly selected users.

    PubMed

    Mehl-Madrona, L E

    1998-01-01

    Frequent users of primary care have not been adequately characterized. The unique characteristics of this population was sought--why they come so often, what their care costs, and whether psychosocial factors play a role in their high utilization of health care. The billing system of a rural primary care clinic was used to find the frequency of visits for all patients attending the clinic for the previous 12 months. The 211 most frequent visitors were selected. A comparison group of 250 patients was drawn from the billing records using a random number generator. Charts were reviewed to compare diagnoses (by frequency), number of procedures, amount billed for care, amount received from those billings, number of psychotropic medications prescribed, and response to medication. A subgroup of each group was interviewed to confirm chart review findings and to inquire about personal reasons for coming to the clinic. Compared with patients who were random users, patients who were frequent users were more likely to come from the younger and older age groups, they averaged significantly more emergency department visits and visits to other specialists (P < 0.0001), and they had more mental health problems diagnosed (P < 0.01). Significantly more frequent users were insured by Medicaid and fewer were insured by Medicare. They had more detailed office visits and more laboratory tests. They received twice as much psychotherapy and had a higher percentage of problem-focused office visits. Chart audits and interviews of selected patients revealed that many nonmedical reasons were related to visits in addition to psychosocial stressors. Nonmedical factors are important among the most frequent users of a primary care clinic. Proposals to improve care for frequent users should consider the psychosocial needs of this population.

  15. End-Users: Dollars but Doubts.

    ERIC Educational Resources Information Center

    Arnold, Stephen E.

    1989-01-01

    Identifies existing categories of end users of online information retrieval systems, discusses problems that have been encountered by information providers and customers, and suggests strategies for capturing new end-user markets. Issues discussed include user cordial interfaces, CD-ROM products, ethics involved in information provision, and…

  16. Sustainable Land Imaging User Requirements

    NASA Astrophysics Data System (ADS)

    Wu, Z.; Snyder, G.; Vadnais, C. M.

    2017-12-01

    The US Geological Survey (USGS) Land Remote Sensing Program (LRSP) has collected user requirements from a range of applications to help formulate the Landsat 9 follow-on mission (Landsat 10) through the Requirements, Capabilities and Analysis (RCA) activity. The USGS is working with NASA to develop Landsat 10, which is scheduled to launch in the 2027 timeframe as part of the Sustainable Land Imaging program. User requirements collected through RCA will help inform future Landsat 10 sensor designs and mission characteristics. Current Federal civil community users have provided hundreds of requirements through systematic, in-depth interviews. Academic, State, local, industry, and international Landsat user community input was also incorporated in the process. Emphasis was placed on spatial resolution, temporal revisit, and spectral characteristics, as well as other aspects such as accuracy, continuity, sampling condition, data access and format. We will provide an overview of the Landsat 10 user requirements collection process and summary results of user needs from the broad land imagining community.

  17. SOL - SIZING AND OPTIMIZATION LANGUAGE COMPILER

    NASA Technical Reports Server (NTRS)

    Scotti, S. J.

    1994-01-01

    SOL is a computer language which is geared to solving design problems. SOL includes the mathematical modeling and logical capabilities of a computer language like FORTRAN but also includes the additional power of non-linear mathematical programming methods (i.e. numerical optimization) at the language level (as opposed to the subroutine level). The language-level use of optimization has several advantages over the traditional, subroutine-calling method of using an optimizer: first, the optimization problem is described in a concise and clear manner which closely parallels the mathematical description of optimization; second, a seamless interface is automatically established between the optimizer subroutines and the mathematical model of the system being optimized; third, the results of an optimization (objective, design variables, constraints, termination criteria, and some or all of the optimization history) are output in a form directly related to the optimization description; and finally, automatic error checking and recovery from an ill-defined system model or optimization description is facilitated by the language-level specification of the optimization problem. Thus, SOL enables rapid generation of models and solutions for optimum design problems with greater confidence that the problem is posed correctly. The SOL compiler takes SOL-language statements and generates the equivalent FORTRAN code and system calls. Because of this approach, the modeling capabilities of SOL are extended by the ability to incorporate existing FORTRAN code into a SOL program. In addition, SOL has a powerful MACRO capability. The MACRO capability of the SOL compiler effectively gives the user the ability to extend the SOL language and can be used to develop easy-to-use shorthand methods of generating complex models and solution strategies. The SOL compiler provides syntactic and semantic error-checking, error recovery, and detailed reports containing cross-references to show where

  18. User recommendation in healthcare social media by assessing user similarity in heterogeneous network.

    PubMed

    Jiang, Ling; Yang, Christopher C

    2017-09-01

    The rapid growth of online health social websites has captured a vast amount of healthcare information and made the information easy to access for health consumers. E-patients often use these social websites for informational and emotional support. However, health consumers could be easily overwhelmed by the overloaded information. Healthcare information searching can be very difficult for consumers, not to mention most of them are not skilled information searcher. In this work, we investigate the approaches for measuring user similarity in online health social websites. By recommending similar users to consumers, we can help them to seek informational and emotional support in a more efficient way. We propose to represent the healthcare social media data as a heterogeneous healthcare information network and introduce the local and global structural approaches for measuring user similarity in a heterogeneous network. We compare the proposed structural approaches with the content-based approach. Experiments were conducted on a dataset collected from a popular online health social website, and the results showed that content-based approach performed better for inactive users, while structural approaches performed better for active users. Moreover, global structural approach outperformed local structural approach for all user groups. In addition, we conducted experiments on local and global structural approaches using different weight schemas for the edges in the network. Leverage performed the best for both local and global approaches. Finally, we integrated different approaches and demonstrated that hybrid method yielded better performance than the individual approach. The results indicate that content-based methods can effectively capture the similarity of inactive users who usually have focused interests, while structural methods can achieve better performance when rich structural information is available. Local structural approach only considers direct connections

  19. 7 CFR 29.425 - Submission and disposition of pesticide residues and end user(s) certification.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... AGRICULTURE COMMODITY STANDARDS AND STANDARD CONTAINER REGULATIONS TOBACCO INSPECTION Regulations... a form approved by the Director for each lot of flue-cured or burley tobacco, including stems... end users so identified shall also complete an end user(s) certification until the tobacco is used in...

  20. Image-Processing Program

    NASA Technical Reports Server (NTRS)

    Roth, D. J.; Hull, D. R.

    1994-01-01

    IMAGEP manipulates digital image data to effect various processing, analysis, and enhancement functions. It is keyboard-driven program organized into nine subroutines. Within subroutines are sub-subroutines also selected via keyboard. Algorithm has possible scientific, industrial, and biomedical applications in study of flows in materials, analysis of steels and ores, and pathology, respectively.