Sample records for composite single-lap joints

  1. The effect of a spew fillet on adhesive stress distributions in laminated composite single-lap joints

    Microsoft Academic Search

    J. Morton

    1995-01-01

    A laminated composite single-lap joint without a spew fillet, subjected to tensile loading, is investigated experimentally and numerically. By directly comparing the experimentally- and numerically-determined deformations of the single-lap joints with and without a fillet, the effect of a spew fillet on adhesive stress distributions is discussed. Moiré interferometry is used to measure the in-plane surface deformation of the overlap

  2. Three-dimensional stress analysis of bolted single-lap composite joints

    Microsoft Academic Search

    Tomas Ireman

    1998-01-01

    A three-dimensional finite element model of bolted composite joints has been developed to determine non-uniform stress distributions through the thickness of composite laminates in the vicinity of a bolt hole. An experimental programme was conducted to measure deformations, strains, and bolt load on test specimens for validation of the numerical model developed. Strains in the radial direction at different radii

  3. Effect of adherend's rigidity on the shear strength of single lap adhesive joints

    Microsoft Academic Search

    P. N. B. Reis; J. A. M. Ferreira; F. Antunes

    2011-01-01

    The present paper compares the tensile shear strength of single-lap joints with different adherends. Three materials were combined in the single lap joints: a carbon\\/epoxy laminated composite, a high elastic limit steel and the 6082-T6 aluminium alloy. The shear strength of joints was influenced by the adherend stiffness and the highest shear strengths were obtained using high stiffness adherend materials.

  4. A Semi-Analytical Method for Determining the Energy Release Rate of Cracks in Adhesively-Bonded Single-Lap Composite Joints

    NASA Technical Reports Server (NTRS)

    Yang, Charles; Sun, Wenjun; Tomblin, John S.; Smeltzer, Stanley S., III

    2007-01-01

    A semi-analytical method for determining the strain energy release rate due to a prescribed interface crack in an adhesively-bonded, single-lap composite joint subjected to axial tension is presented. The field equations in terms of displacements within the joint are formulated by using first-order shear deformable, laminated plate theory together with kinematic relations and force equilibrium conditions. The stress distributions for the adherends and adhesive are determined after the appropriate boundary and loading conditions are applied and the equations for the field displacements are solved. Based on the adhesive stress distributions, the forces at the crack tip are obtained and the strain energy release rate of the crack is determined by using the virtual crack closure technique (VCCT). Additionally, the test specimen geometry from both the ASTM D3165 and D1002 test standards are utilized during the derivation of the field equations in order to correlate analytical models with future test results. The system of second-order differential field equations is solved to provide the adherend and adhesive stress response using the symbolic computation tool, Maple 9. Finite element analyses using J-integral as well as VCCT were performed to verify the developed analytical model. The finite element analyses were conducted using the commercial finite element analysis software ABAQUS. The results determined using the analytical method correlated well with the results from the finite element analyses.

  5. Failure strength prediction for adhesively bonded single lap joints

    NASA Astrophysics Data System (ADS)

    Rahman, Niat Mahmud

    For adhesively bonded joint, failure strength depends on many factors such as material properties (both adhesive and adherend), specimen geometries, test environments, surface preparation procedures, etc. Failure occurs inside constitutive materials or along joint interfaces. Based on location, adhesively bonded failure mode can be classified as adhesive failure mode, cohesive failure mode and adherend failure mode. Failure mode directly affects the failure strength of joint. For last eight decades, researchers have developed analytical, empirical or semi-empirical methods capable of predicting failure strength for adhesively bonded joints generating either cohesive failure or adherend failure. Applicability of most of the methods is limited to particular cases. In this research, different failure modes for single lap joints (SLJs) were generated experimentally using epoxy based paste adhesive. Based on experimental data and analytical study, simplified failure prediction methods were developed for each failure mode. For adhesive failure mode, it is observed that peel stress distributions concur along interface near crack initiation points. All SLJs for this test endured consistent surface treatments. Geometric parameters of the joints were varied to study their effect on failure strength. Peel stress distributions were calculated using finite analysis (FEA). Based on peel stress distribution near crack initiation point, a failure model is proposed. Numerous analytical, empirical and semi-empirical models are available for predicting failure strengths of SLJs generating cohesive failures. However, most of the methods in the literature failed to capture failure behavior of SLJs having thickness of adhesive layer as variable. Cohesive failure mode was generated experimentally using aluminum as adherend and epoxy adhesive considering thickness of adhesive layers as variable within SLJs. Comparative study was performed among various methods. It was observed that experimentally measured crack tip opening angles (CTOA) using DCB tests and CTOAs extracted from FEA using SLJs at failure loads follow similar trend when adhesive thickness was considered as variable. A factor was proposed to accommodate differences. Proposed method was also adopted for SLJs with overlap length as variable. Reasons for discrepancies were identified for such case. For generating adherend failure, graphite fiber epoxy composite was used as adherend. To avoid singularity, an area based approach was adopted. It is considered that failure within composite adherend occurs when size of the damaged zone reaches a critical value. This value was determined using test data and then FEA of SLJ. Using this hypothesis, various strength of material based failure models were tested for SLJs with different geometries. According to the study, Azzi-Tsai model works well for SLJs having different geometric parameters. Only composite failure parallel to interface and within the first ply was considered here.

  6. Optimal Design of the Adhesively-Bonded Tubular Single Lap Joint

    Microsoft Academic Search

    Su Jeong Lee; Dai Gil Lee

    1995-01-01

    In this paper, a method for the optimal design of the adhesively-bonded tubular single lap joint was proposed based on the failure model of the adhesively-bonded tubular single lap joint. The failure model incorporated the nonlinear mechanical behavior of the adhesive as well as the different failure modes in which the adhesive failure mode changed from bulk shear failure, via

  7. Tensile Strength of Single Lap Joint and Scarf Joint between CFRP and Carbon Steel

    Microsoft Academic Search

    Chiaki Sato; Kozo Ikegami

    1992-01-01

    The strength of single lap joints and scarf joints between carbon cloth laminated plastics (CFRP) and carbon steel bonded with epoxy resin was investigated both analytically and experimentally. The stress and strain distributions under tensile loads of the joints were analyzed by applying the elastic finite element method.The strength of the joints was predicted by applying the strength law of

  8. Bond strength for adhesive-bonded single-lap joints

    Microsoft Academic Search

    L. Tong

    1996-01-01

    Summary Arbitrarily nonlinear stress-strain behaviour in both shear and peel for adhesive are utilised to formulate two coupled nonlinear governing equations for an adhesive-adherend sandwich of single-lap type. For a balanced adhesive-adherend sandwich, the two equations can be integrated, and simple formulas for bond strength are developed for characterising pure shear, peel and mixed failure in adhesive. These formulas define

  9. Use of a single lap shear test to characterize composite-to-concrete or composite-to-steel bonded interfaces

    Microsoft Academic Search

    Sylvain Chataigner; Jean-Francois Caron; Karim Benzarti; Marc Quiertant; Christophe Aubagnac

    2011-01-01

    Adhesively bonded composite reinforcements are increasingly being used for civil engineering structures. For an adequate use of such a technique, a better knowledge is needed regarding the stress transfer mechanisms involved in polymer joints. This article introduces a single lap shear test for the characterization of the composite-to-concrete or composite-to-steel bonded assemblies. In the first part, an extensive description of

  10. Dynamic response of adhesively bonded single-lap joints with a void subjected to harmonic peeling

    E-print Network

    Vaziri, Ashkan

    Dynamic response of adhesively bonded single-lap joints with a void subjected to harmonic peeling is evaluated. The bonded joint is modelled as a Euler­Bernoulli beam joined with an adhesive and constrained overall length of the bonded joint t adhesive thickness w width of the beams yi transverse displacement

  11. Effect of metal as part of fillet on the tensile shear strength of adhesively bonded single lap joints

    Microsoft Academic Search

    Min You; Yong Zheng; Xiao-Ling Zheng; Wen-Jun Liu

    2003-01-01

    The effect of fillet containing metallic components on the strength of adhesively bonded single lap joints has been undertaken by alternating the shape and size of metallic components as a part of fillet or whole fillet at the end of the joints. Mild carbon steel and epoxy structural adhesive were used to prepare single lap-shear joints. Three types of steel

  12. A critical examination of stresses in an elastic single lap joint

    NASA Technical Reports Server (NTRS)

    Cooper, P. A.; Sawyer, J. W.

    1979-01-01

    The results of an approximate nonlinear finite-element analysis of a single lap joint are presented and compared with the results of a linear finite-element analysis, and the geometric nonlinear effects caused by the load-path eccentricity on the adhesive stress distributions are determined. The results from finite-element, Goland-Reissner, and photoelastic analyses show that for a single lap joint the effect of the geometric nonlinear behavior of the joint has a sizable effect on the stresses in the adhesive. The Goland-Reissner analysis is sufficiently accurate in the prediction of stresses along the midsurface of the adhesive bond to be used for qualitative evaluation of the influence of geometric or material parametric variations. Detailed stress distributions in both the adherend and adhesive obtained from the finite-element analysis are presented to provide a basis for comparison with other solution techniques.

  13. Investigation of aluminum single lap adhesively bonded joints

    Microsoft Academic Search

    M. Luci?; A. Stoi?; I. B. Mažurani?

    Purpose: The purpose of research was to find an optimum overlap length ensuring the settled bearing performance of adhesive bonded joint. At the optimum overlap length it is possible to reach a maximum load bearing capacity using a minimum quantity of applied adhesive. Design\\/methodology\\/approach: In accordance with experimental test results, an optimum overlap length was achieved. In numerical analysis, the

  14. Strain measurement within a single-lap joint using embedded strain gages

    NASA Technical Reports Server (NTRS)

    Tuttle, M. E.; Barthelemy, B. M.; Brinson, H. F.

    1984-01-01

    An experimental method used to measure the in-plane normal-axial strains produced within a single-lap joint is described in which a resistance-foil strain gage is embedded within the joint prior to curing of the adhesive. Nominal dimensions of the titanium Ti-6-4 adherends were 0.13 x 2.5 x 12.7 cm and an overlap of 2.5 cm was used. The joint was bonded with FM-300 structural adhesive. The average ultimate shear strength of the gaged specimens and control specimens was 16.1 MPa and 14.1 MPa. A significant advantage of the proposed method is that strains internal to the joint are measured, rather than strains at an external edge. The presence of the gage was found to be not detrimental to bond performance.

  15. Effect of temperature on the shear strength of aluminium single lap bonded joints for high temperature applications

    Microsoft Academic Search

    M. D. Banea; L. F. M. da Silva; R. D. S. G. Campilho

    2012-01-01

    An experimental and numerical investigation into the shear strength behaviour of adhesive single lap joints (SLJs) was carried out in order to understand the effect of temperature on the joint strength. The adherend material used for the experimental tests was an aluminium alloy in the form of thin sheets, and the adhesive used was a high-strength high temperature epoxy. Tensile

  16. Stress-Strain Analysis of Single-Lap Tensile Loaded Adhesive Joints

    SciTech Connect

    Raos, Pero; Kozak, Drazan; Lucic, Mirjana [University of Osijek, Mechanical Engineering Faculty in Slavonski Brod, Trg Ivane Brlic-Mazuranic 2, HR-35000 Slavonski Brod (Croatia)

    2007-05-17

    Both, experimental investigation and finite element analysis of single-lap adhesive joints subjected to tension have been done to find out an optimal overlap length. As the adherend material aluminum was considered with the two component high-strength engineering adhesive for the bonding of the layers. The thickness of the sheet metal layer was 1,95 mm, while adhesive was 0,15 mm thick. The width of all thin plates was 30 mm, but the overlap length varied as 15, 20, 30, 40 and 60 mm. Real mechanical properties of all materials in the joint have been determined experimentally. Obtained results proved that the overlap length affects directly the joint tensile strength, where an optimum value of overlap length can be defined. Finite element analysis of stress and strain fields could help to determine the moment when the crack initiates at the joint overlap end. In such a manner, complex mechanisms of failure of adhesive joints could be better understood.

  17. Correlation of single lap joint strength, and deformation with joint resistance, surface, and cure conditions

    Microsoft Academic Search

    E. Sancaktar; R. Gomatam

    2000-01-01

    For achieving a reliable adhesive bond, the adhesive must properly wet the surface asperities on the adherend before any other physical or chemical phenomena can take place. The physical phenomenon of mechanical interlocking is related to the surface morphology of the adherend. Generally, a rough surface increases adhesive joint strength, by enhancing the surface area and the extent of mechanical

  18. Analysis of manufacturing parameters on the shear strength of aluminium adhesive single-lap joints

    Microsoft Academic Search

    A. M. Pereira; J. M. Ferreira; F. V. Antunes; P. J. Bártolo

    2010-01-01

    An experimental and numerical investigation into the shear strength behaviour of aluminium alloy adhesive lap joints was carried out in order to understand the effect of geometrical and manufacturing parameters on the strength of adhesive bonding joints, with the aim of optimizing shear strength. The adherend material used for the experimental tests was an aluminium alloy in the form of

  19. Dynamic strain distribution measurement and crack detection of an adhesive-bonded single-lap joint under cyclic loading using embedded FBG

    NASA Astrophysics Data System (ADS)

    Ning, Xiaoguang; Murayama, Hideaki; Kageyama, Kazuro; Wada, Daichi; Kanai, Makoto; Ohsawa, Isamu; Igawa, Hirotaka

    2014-10-01

    In this study, the dynamic strain distribution measurement of an adhesive-bonded single-lap joint was carried out in a cyclic load test using a fiber Bragg grating (FBG) sensor embedded into the adhesive/adherend interface along the overlap length direction. Unidirectional carbon fiber reinforced plastic (CFRP) substrates were bonded by epoxy resin to form the joint, and the FBG sensor was embedded into the surface of one substrate during its curing. The measurement was carried out with a sampling rate of 5 Hz by the sensing system, based on the optical frequency domain reflectometry (OFDR) throughout the test. A finite element analysis (FEA) was performed for the measurement evaluation using a three-dimensional model, which included the embedded FBG sensor. The crack detection method, based on the longitudinal strain distribution measurement, was introduced and performed to estimate the cracks that occurred at the adhesive/adherend interface in the test.

  20. Properties and failure mechanisms of pinned composite lap joints in monotonic and cyclic tension

    Microsoft Academic Search

    P. Chang; A. P. Mouritz; B. N. Cox

    2006-01-01

    The effect of through-thickness reinforcement by fibrous pins on the static tensile strength, fatigue life and failure mechanisms of single lap joints made of carbon\\/epoxy composite is investigated. Pinning is highly effective in increasing the ultimate strength, elongation limit and fatigue life. Improvements to the monotonic and fatigue properties are attributed to transitions in the failure mechanisms, from unstable joint

  1. Numerical study of lap joints with composite adhesives and composite adherends subjected to in-plane and transverse loads

    Microsoft Academic Search

    S. M. R. Khalili; M. R. Pirouzhashemi; A. Shokuhfar; R. K. Mittal

    2008-01-01

    In this paper, single lap joints for joining fibre composites were modeled and a three-dimensional finite element method was used to study the joint strength under in-plane tensile and out-of-plane loadings. The behaviour of all the members was assumed to be linear elastic. The adherends were considered to be orthotropic materials while the adhesive could be neat resin or reinforced

  2. Study of joint designing on composite structures

    NASA Astrophysics Data System (ADS)

    Kazushi, Haruna

    In this paper, strength design techniques of CFRP mechanical joints and adhesively bonded joints were examined. Remarkable stress concentration generates at the mechanical hole edge and the adhesive edge, therefore an unskillful design of joints often causes a reduction in the strength of composite structures. In mechanical joints, a study on predicting the joint strength has been performed, but bearing failure that is most important failure mode for designing joints can not be predicted. So in this paper, the strength prediction method in consideration with bearing failure was examined. On the other hand, the criterion using the intensity of stress singularity was suggested in adhesive joints, but it was clarified in this paper, that this method can not be applied the prediction of the final failure strength. So the critical stress distribution of single-lap adhesive bonded carbon/epoxy joints was examined to obtain the failure criterion of the final failure. Moreover the simulation method for an internal stress generated by cure shrinkage of adhesive was also examined. In the proposed method for mechanical joint, 2-parameter criterion, that is combined the characteristic length with the Yamada-Sun criterion, was applied and the characteristic length for compression was determined from "bearing failure test" that was newly conceived to take bearing failure into consideration. In case of adhesive joints, it was thought that 2-parameter criterion was effective. So the prediction method using 2-parameter criterion was applied to other adhesive joints. Good agreement was obtained between predicted and experimental results in both mechanical and adhesive joints. And it was cleared that an internal stress could be simulated by the proposed method. Moreover, in mechanical joints, the most suitable stacking sequence, the reduction technique of interlaminar stress, and the elevation of joint strength by application of high toughness matrix were also shown. Consequently, mechanical and adhesively joints in composite structures could be designed and basic data for high reliable design could be established.

  3. Non destructive evaluation of adhesively bonded carbon fiber reinforced composite lap joints with varied bond quality

    NASA Astrophysics Data System (ADS)

    Vijayakumar, R. L.; Bhat, M. R.; Murthy, C. R. L.

    2012-05-01

    Structural adhesive bonding is widely used to execute assemblies in automobile and aerospace structures. The quality and reliability of these bonded joints must be ensured during service. In this context non destructive evaluation of these bonded structures play an important role. Evaluation of adhesively bonded composite single lap shear joints has been attempted through experimental approach. Series of tests, non-destructive as well as destructive were performed on different sets of carbon fiber reinforced polymer (CFRP) composite lap joint specimens with varied bond quality. Details of the experimental investigations carried out and the outcome are presented in this paper.

  4. Design, fabrication and test of graphite/polyimide composite joints and attachments for advanced aerospace vehicles

    NASA Technical Reports Server (NTRS)

    Barclay, D. L.

    1980-01-01

    Results of an experimental program to develop several types of graphite/polyimide (GR/PI) bonded and bolted joints for lightly loaded flight components for advanced space transportation systems and high speed aircraft are presented. Tasks accomplished include: a literature survey; design of static discriminator specimens; design allowables testing; fabrication of test panels and specimens; small specimen testing; and standard joint testing. Detail designs of static discriminator specimens for each of the four major attachment types are presented. Test results are given for the following: (1) transverse tension of Celion 3000/PMR-15 laminate; (2) net tension of a laminate for both a loaded and unloaded bolt hole; (3) comparative testing of bonded and co-cured doublers along with pull-off tests of single and double bonded angles; (4) single lap shear tests, transverse tension and coefficient of thermal expansion tests of A7F (LARC-13 amide-imide modified) adhesive; and (5) tension tests of standard single lap, double lap, and symmetric step lap bonded joints. Also, included are results of a finite element analysis of a single lap bonded composite joint.

  5. Three-Dimensional Solutions for Contact Area in Laminated Composite Pinned Joints with Symmetric and Non-Symmetric Stacking Sequences

    NASA Astrophysics Data System (ADS)

    Javadi, H.; Rajabi, I.; Yavari, V.; Kadivar, M. H.

    The aim of this study is computing and evaluating the behavior of the laminated composite plate at the contact area in single lap, mechanically fastened joints. The analyses involve three dimensional finite element models performed by ABAQUS 6.4-PR11 code to evaluate the stress distribution in contact surface, separation angle, the magnitude and location of maximum radial stress. Results are determined for composite laminates with different layer configurations and attempts are made to validate the models with previous works. For cross ply and angle ply configurations only symmetric stacking sequences are used while for quasi-isotropic laminate both symmetric and non-symmetric models are generated. In cross-ply laminate symmetric separation about bearing plane could be found while in quasi-isotropic and angle-ply laminates non-symmetric separation occurs. Also, the separation angle is less than 90° in symmetric laminates and greater than 90° in some plies of non-symmetric laminates.

  6. Advances in the analysis and design of adhesive-bonded joints in composite aerospace structures

    NASA Technical Reports Server (NTRS)

    Hart-Smith, L. J.

    1974-01-01

    Several aspects of adhesive-bonded joint analysis and design are presented from the reference of size of structure or load intensity. This integrates the individual characterizations of double-lap, single-lap, stepped-lap, tapered-lap and scarf joints. The paper includes an overview of bonded joint selection from the standpoints of design, fabrication, and processing, each bearing in mind the influence of such considerations on the strength of the joint. A case study is presented of the optimization of a specific relatively thick titanium-to-graphite epoxy stepped-lap joint, using the digital computer analysis program A4EG. The factors accounted for are adhesive plasticity, adherend stiffness imbalance, adherend thermal mismatch, and change of material properties within the range of temperature environment and with load direction. The strength increases obtainable by refining the initial design are demonstrated.

  7. Conception axiomatique des joints hybrides a recouvrement simple en materiaux composites

    NASA Astrophysics Data System (ADS)

    Ouellet, Marc

    Minimizing weight is a primary objective in every system design in the aerospace and automotive industry. Therefore, the use of composite materials has become an integral part of the design of mechanical components. However, in composite structure design, their complexity normally makes it impossible to design them as a single part. This leads to the necessity of using joints. Sadly, these joints introduce discontinuities in the stress distribution within the components and are often the sites of stress concentration. Therefore, they may limit the performance of a structure, in addition to increasing the overall mass significantly due to the use of mechanical fasteners such as bolts and rivets. This is why bonded joints are increasingly popular. They are much lighter than bolted or riveted joints and are often more rigid. Unfortunately, it is very difficult to inspect a bonded joint for defects since the presence of cracks in the adhesive cannot be observed with the naked eye. The main objective of this work is to propose a new design methodology for hybrid joints. To accomplish this, it is necessary to establish reliable analysis tools to improve our understanding of the behavior of these joints when subjected to an external force. A better understanding of the interactions between the parameters is also required. To improve our knowledge on the subject, a literature review was conducted. This review was structured as to emphasize on the behavior of hybrid single lap joints when subjected to an external force in tension. Following this literature review, an analysis of the stress distribution within the joint was carried out using a finite element model. The model and the results were compared with those from two papers in order to validate the quality of representation. Subsequently, a modification was made to an existing analytical model in order to add the bolts' preload as a parameter. These two models, namely the finite element model and the analytical model, were then used for a sensitivity study using a design of experiments. To perform this analysis, a kriging model was used to reduce the computing time. Finally, the hybrid single lap joint was analyzed using axiomatic design in order to propose new approach to design these joints. The results of this work can be divided into three parts. First, an analytical model identified in the literature review has been improved to take into account the bolts' preload. The results are satisfactory within the limitations of the original model. It must be pointed out that this model does not consider the non-linear behavior of materials used in the joint, which can lead to poor reliability when highly non-linear materials are used. The sensitivity analysis carried out using the analytical model and the finite element model identified the influence of the parameters on the mechanical performances of the joint. It should be noted that the width of the joint is one of the most important parameter, as well as the thickness of the adherents. The sensitivity analysis also identified the notable effect of the radial clearance of the bolt shank. This parameter should be minimized in order to maximize performances. Finally, the geometry obtained with the axiomatic design and through physical integration reduced the maximum peel stress considerably. The use of washers based on Belleville springs allowed to significantly increase the area affected by the bolts' preload. Therefore, this final geometry should significantly increase the maximum external load that can be supported by the joint and increase its fatigue life. Finally, an improved geometry was proposed using the theory of axiomatic design. The use of chamfers at the ends of the adherents, the addition of modified washers and the use of a stiffer adhesive between the two bolts have significantly reduced the maximum peel stress in the adhesive layer. These changes have also increased the rigidity of the joint. However, analyzes have not demonstrated a decrease in the maximum shear stress inside the adhesive. Therefore, further

  8. Adhesive joint and composites modeling in SIERRA.

    SciTech Connect

    Ohashi, Yuki; Brown, Arthur A.; Hammerand, Daniel Carl; Adolf, Douglas Brian; Chambers, Robert S.; Foulk, James W., III (.,; )

    2005-11-01

    Polymers and fiber-reinforced polymer matrix composites play an important role in many Defense Program applications. Recently an advanced nonlinear viscoelastic model for polymers has been developed and incorporated into ADAGIO, Sandia's SIERRA-based quasi-static analysis code. Standard linear elastic shell and continuum models for fiber-reinforced polymer-matrix composites have also been added to ADAGIO. This report details the use of these models for advanced adhesive joint and composites simulations carried out as part of an Advanced Simulation and Computing Advanced Deployment (ASC AD) project. More specifically, the thermo-mechanical response of an adhesive joint when loaded during repeated thermal cycling is simulated, the response of some composite rings under internal pressurization is calculated, and the performance of a composite container subjected to internal pressurization, thermal loading, and distributed mechanical loading is determined. Finally, general comparisons between the continuum and shell element approaches for modeling composites using ADAGIO are given.

  9. An improved 2D model for bonded composite joints

    Microsoft Academic Search

    Randolph A. Odi; Clifford M. Friend

    2004-01-01

    A growing number of structural applications and repairs require strong adhesively bonded joints between composite parts. The viability of the finite elements method (FEM) for the design and analysis of such joints has been shown by several researchers (Composites 13(1982) 29, mechanics and mechanisms of damage in composites and multi-materials, ESIS11, Mechanical Engineering Publications, London, 1991, Structural adhesive joints in

  10. 21 CFR 888.3100 - Ankle joint metal/composite semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 false Ankle joint metal/composite semi-constrained cemented prosthesis... § 888.3100 Ankle joint metal/composite semi-constrained cemented prosthesis...Identification. An ankle joint metal/composite semi-constrained cemented...

  11. 21 CFR 888.3100 - Ankle joint metal/composite semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 2012-04-01 false Ankle joint metal/composite semi-constrained cemented...Prosthetic Devices § 888.3100 Ankle joint metal/composite semi-constrained cemented...a) Identification. An ankle joint metal/composite...

  12. 21 CFR 888.3340 - Hip joint metal/composite semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Hip joint metal/composite semi-constrained...Prosthetic Devices § 888.3340 Hip joint metal/composite semi-constrained...prosthesis. (a) Identification. A hip joint metal/composite...

  13. Autonomous sensing of composites with carbon nanotubes for structural health monitoring

    NASA Astrophysics Data System (ADS)

    Liu, Yingtao; Yekani Fard, Masoud; Rajadas, Abhishek; Chattopadhyay, Aditi

    2012-04-01

    The development of structural health monitoring techniques leads to the integration of sensing capability within engineering structures. This study investigates the application of multi walled carbon nanotubes in polymer matrix composites for autonomous damage detection through changes in electrical resistance. The autonomous sensing capabilities of fiber reinforced nanocomposites are studied under multiple loading conditions including tension loads. Single-lap joints with different joint lengths are tested. Acoustic emission sensing is used to validate the matrix crack propagation. A digital image correlation system is used to measure the shear strain field of the joint area. The joints with 1.5 inch length have better autonomous sensing capabilities than those with 0.5 inch length. The autonomous sensing capabilities of nanocomposites are found to be sensitive to crack propagation and can revolutionize the research on composite structural health management in the near future.

  14. Capacity prediction of welded timber joints

    Microsoft Academic Search

    Till Vallée; Thomas Tannert; Christelle Ganne-Chedville

    Linear vibration welding of timber structural elements provides new opportunities to potentially achieve structural joints.\\u000a This paper investigates to which extent welded joints can be considered for load-bearing structural joints. On the basis of\\u000a a series of experimental and numerical investigations on a series of welded single-lap joints, failure modes were identified,\\u000a and the associated failure criterion was quantified. A

  15. Simplified procedures for designing adhesively bonded composite joints

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.; Murthy, P. L. N.

    1991-01-01

    Procedures for the preliminary design for composite adhesive joints are described. Typical joints, their respective free body diagrams, and approximate equations for estimating the stresses in each of these typical joints are summarized. Equations are also presented to check the critical conditions of the joint such as minimum length, maximum adhesive shear stress, and peel-off stress. To illustrate the procedure, sample designs are described in step-by-step fashion for a butt joint with single doubler subjected to static loads, cyclic loads, and environmental effects. The results show that unsymmetric adhesive joints are inefficient and should be avoided, and hygrothermal environments and cyclic loads dramatically reduce the structural integrity of the joint and require several joint lengths compared with those for static load with no environmental effects.

  16. Simplified procedures for designing adhesively bonded composite joints

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.; Murthy, P. L. N.

    1989-01-01

    Procedures for the preliminary design of composite adhesive joints are described. Typical joints, their respective free body diagrams, and approximate equations for estimating the stresses in each of these typical joints are summarized. Equations are also presented to check the critical conditions of the joint such as minimum length, maximum adhesive shear stress, and peel-off stress. To illustrate the procedure, sample designs are described in step-by-step fashion for a butt joint with single doubler subjected to static loads, cyclic loads, and environmental effects. The results show that unsymmetric adhesive joints are inefficient and should be avoided, and hygrothermal environments and cyclic loads dramatically reduce the structural integrity of the joint and require several joint lengths compared with those for static load with no environmental effects.

  17. A generalised damage model for constant amplitude fatigue loading of adhesively bonded joints

    Microsoft Academic Search

    H. Khoramishad; A. D. Crocombe; K. B. Katnam; I. A. Ashcroft

    2010-01-01

    The fatigue resistance of adhesively bonded joints is an important aspect of reliable structural design in many sectors. In this paper, the effect of load ratio on the fatigue behaviour of adhesively bonded joints was investigated using both experimental and numerical approaches. Single lap joints were tested under cyclic loading at different load ratios and load levels to characterise their

  18. Fatigue of boron-aluminum composites bonds and joints

    NASA Technical Reports Server (NTRS)

    Hersh, M. S.

    1973-01-01

    Study examines effects of boron filament diameter on bonds and joints in boron-aluminum composite. Data include static strength, fatigue, and dynamic moduli of elasticity. Manson-Coffin analyses and metallurgical and fracture surface evaluation were also performed.

  19. The effects of inherent flaws on the time and rate dependent failure of adhesively bonded joints

    NASA Technical Reports Server (NTRS)

    Sancaktar, E.; Padgilwar, S.

    1982-01-01

    Inherent flaws, as well as the effects of rate and time, are shown by tests on viscoelastic adhesive-bonded single lap joints to be as critical in joint failure as environmental and stress concentration effects, with random inherent flaws and loading rate changes resulting in an up to 40% reduction in joint strength. It is also found that the asymptotic creep stress, below which no delayed failure may occur, may under creep loading be as much as 45% less than maximum adhesive strength. Attention is given to test results for the case of titanium-LARC-3 adhesive single-lap specimens.

  20. Functionally Graded Adhesives for Composite Joints

    NASA Technical Reports Server (NTRS)

    Stapleton, Scott E.; Waas, Anthony M.; Arnold, Steven M.

    2012-01-01

    Adhesives with functionally graded material properties are being considered for use in adhesively bonded joints to reduce the peel stress concentrations located near adherend discontinuities. Several practical concerns impede the actual use of such adhesives. These include increased manufacturing complications, alterations to the grading due to adhesive flow during manufacturing, and whether changing the loading conditions significantly impact the effectiveness of the grading. An analytical study is conducted to address these three concerns. An enhanced joint finite element, which uses an analytical formulation to obtain exact shape functions, is used to model the joint. Furthermore, proof of concept testing is conducted to show the potential advantages of functionally graded adhesives. In this study, grading is achieved by strategically placing glass beads within the adhesive layer at different densities along the joint.

  1. Predicting the service-life of adhesively-bonded joints

    Microsoft Academic Search

    A. J. Curley; H. Hadavinia; A. J. Kinloch; A. C. Taylor

    2000-01-01

    A fracture-mechanics approach has been used to predict the cyclic-fatigue performance of the adhesively-bonded single-lap joint and a typical bonded component, represented by an adhesively-bonded `top-hat' box-beam joint. The joints were tested under cyclic-fatigue loading in either a `wet' or `dry' environment, respectively. Several steps were needed to predict the cyclic-fatigue lifetime of these joints. Firstly, fracture-mechanics tests were used

  2. Assessment of the fatigue life of aluminium spot-welded and weld-bonded joints

    Microsoft Academic Search

    A. M. Pereira; J. A. M. Ferreira; F. V. Antunes; P. J. Bártolo

    2012-01-01

    In modern machinery and automobile structures weight reduction and increased durability are the main issues in design. In these applications, lap welded and\\/or bonded joints are widely used; therefore, tools are needed to accurately predict their fatigue life. This paper is concerned with the fatigue strength of single lap joints formed with thin plates of 6082-T6 aluminium alloy using a

  3. The strength of metal-matrix composite joints

    SciTech Connect

    Burr, A.; Yang, J.Y.; Levi, C.G.; Leckie, F.A. [Univ. of California, Santa Barbara, CA (United States). Dept. of Materials and Mechanical Engineering] [Univ. of California, Santa Barbara, CA (United States). Dept. of Materials and Mechanical Engineering

    1995-09-01

    The mechanical performance of model butt joints between Al-matrix composites reinforced with continuous alumina fibers has been investigated. The joints consisted of thin metal interlayers of varying geometries and thicknesses, normal to the fiber preforms with prescribed discontinuities in them, thus ensuring matrix continuity through the interlayer and minimization of processing defects normally introduced in actual joining operations. Tensile strengths for reference composite specimens with volume fractions in the 60{+-}5 vol.% range were on the order of 700 MPa, compared with a matrix yield strength of {sigma}{sub 0}{approx}100 MPa. Measured joint strengths were {approximately}250 MPa for interlayers of uniform thickness (60 and 300 {micro}m) wherein plane strain conditions predominated, and {approximately}170 MPa for interlayers of variable thickness ({le} 6.4 mm) wherein conditions changed from plane strain to plane stress. The predominant mode of failure was interfacial debonding at an estimated local stress of {approximately}260 MPa. An upper limit to the joint strength was identified as arising from unstable cavitation in the metal interlayer, expected at a stress of {approximately}4{sigma}{sub 0}. Possible avenues to increase the joint strength to a level consistent with that of the composite are discussed in light of the understanding of failure mechanisms emerging from these model configurations.

  4. Influence of film thickness on joint bend strength of a ceramic\\/resin composite joint

    Microsoft Academic Search

    Margareta K. Molin; Stig L. Karlsson; Mette S. Kristiansen

    1996-01-01

    Objectives. The purpose of this study was to evaluate the influence of different film thicknesses of resin composite luting agents on the joint bend strength of a ceramic\\/resin interface.Methods. Mirage FLC (Chamelon Dental Products) and Vita Cerec (Coltène AG) duo cement were used in combination with the ceramic materials, Mirage and Vita Cerec blocks. Cement layers with thicknesses of 20

  5. Tensile strength of simulated and welded butt joints in W-Cu composite sheet

    NASA Technical Reports Server (NTRS)

    Moore, Thomas J.; Watson, Gordon K.

    1994-01-01

    The weldability of W-Cu composite sheet was investigated using simulated and welded joints. The welded joints were produced in a vacuum hot press. Tensile test results showed that simulated joints can provide strength and failure mode data which can be used in joint design for actual weldments. Although all of the welded joints had flaws, a number of these joints were as strong as the W-Cu composite base material.

  6. Thermally Conductive Metal-Tube/Carbon-Composite Joints

    NASA Technical Reports Server (NTRS)

    Copeland, Robert J.

    2004-01-01

    An improved method of fabricating joints between metal and carbon-fiber-based composite materials in lightweight radiators and heat sinks has been devised. Carbon-fiber-based composite materials have been used in such heat-transfer devices because they offer a combination of high thermal conductivity and low mass density. Metal tubes are typically used to carry heat-transfer fluids to and from such heat-transfer devices. The present fabrication method helps to ensure that the joints between the metal tubes and the composite-material parts in such heat-transfer devices have both (1) the relatively high thermal conductances needed for efficient transfer of heat and (2) the flexibility needed to accommodate differences among thermal expansions of dissimilar materials in operation over wide temperature ranges. Techniques used previously to join metal tubes with carbon-fiber-based composite parts have included press fitting and bonding with epoxy. Both of these prior techniques have been found to yield joints characterized by relatively high thermal resistances. The present method involves the use of a solder (63 percent Sn, 37 percent Pb) to form a highly thermally conductive joint between a metal tube and a carbon-fiber-based composite structure. Ordinarily, the large differences among the coefficients of thermal expansion of the metal tube, solder, and carbon-fiber-based composite would cause the solder to pull away from the composite upon post-fabrication cooldown from the molten state. In the present method, the structure of the solder is modified (see figure) to enable it to deform readily to accommodate the differential thermal expansion.

  7. Fatigue Performance of Marine Composite Doubler Plate Joints under Random Load Spectra

    Microsoft Academic Search

    Steven P. Blake; Roberto A. Lopez-Anido; Fadi W. El-Chiti

    Composite structures commonly fail at secondary bonded joints due to crack propagation at the bond line of the joint. The crack propagation response of second- ary bonded doubler plate joints in fiber-reinforced poly- mer (FRP) composite panels was investigated due to va- riable amplitude fatigue produced by vessel design spec- tra loads. The doubler plate joints were analyzed with respect

  8. ElastoPlastic Failure Analysis of Composite Bolted Joints

    Microsoft Academic Search

    Yoshifumi Tsujimoto; Dale Wilson

    1986-01-01

    An elasto-plastic finite element analysis of pin loaded joints in laminated composites has been investigated and comparisons made with both existing 2-D linear elastic plane stress analytical solutions and experimental results for a graphite\\/epoxy laminate. The finite element analysis included nonlinear material behavior after initial failure by assuming an elastic-perfectly plastic bimodular material model. Laminated plate theory was used to

  9. Non-destructive testing of structural composites and adhesively bonded composite joints: pulsed thermography

    Microsoft Academic Search

    J. A. Schroeder; T. Ahmed; B. Chaudhry; S. Shepard

    2002-01-01

    Structural adhesive bonding is an enabling technology for the implementation of composite assemblies in automotive applications. Therefore, the quality and reliability of the composite bond must be assured. An advanced thermal non-destructive test (NDT) method, pulsed thermography, was evaluated for its capability to assess joint quality in an adhesively bonded composite pickup truck box. Pulsed thermography, used under in-plant, pre-production

  10. Effect of Composite Substrates on the Mechanical Behavior of Brazed Joints in Metal-Composite System

    NASA Technical Reports Server (NTRS)

    Singh, M.; Morscher, Gregory N.; Shpargel, Tarah; Asthana, Rajiv

    2006-01-01

    Advanced composite components are being considered for a wide variety of demanding applications in aerospace, space exploration, and ground based systems. A number of these applications require robust integration technologies to join dissimilar materials (metalcomposites) into complex structural components. In this study, three types of composites (C-C, C-SiC, and SiC-SiC) were vacuum brazed to commercially pure Ti using the active metal braze alloy Cusil-ABA (63Ag-35.3Cu-1.75Ti). Composite substrates with as fabricated and polished surfaces were used for brazing. The microstructure and composition of the joint, examined using scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS), showed sound metallurgical bonding in all systems. The butt strap tensile (BST) test was performed on bonded specimens at room and elevated temperatures. Effect of substrate composition, interlaminar properties, and surface roughness on the mechanical properties and failure behavior of joints will be discussed.

  11. Introductory fatigue tests on welded joints in high strength steel and aluminium improved by various methods including ultrasonic impact treatment (UIT)

    Microsoft Academic Search

    NORWEGIAN DELEGATION; P. J. Haagensen; E. S. Statnikov; L. Lopez-Martinez

    This paper summarizes fatigue test on high strength steel specimens in the as-welded condition and specimens treated by ultrasonic impact treatment, TIG dressing and a combination of TIG dressing and ultrasonic impact treatment. Single lap joint specimens in 6 mm aluminium plate material were tested in the as-welded, hammer peened, needle peened and ground condition. Aluminium joints with longitudinal stiffeners

  12. Mechanically fastened joints in composite laminates: Evaluation of load bearing capacity

    Microsoft Academic Search

    A. A. Pisano; P. Fuschi

    2011-01-01

    Mechanical fasteners, commonly used in many advanced engineering applications dealing with composite laminates, play the main role of transferring loads between the linked structural elements. The present study, focused on pinned-joints, explores the possibility of applying a direct method for evaluating the joint’s strength as well as for predicting some of the more common joint’s failure mechanisms. A limit analysis

  13. Adhesively-bonded joints in metallic alloys, polymers and composite materials: Mechanical and environmental durability performance

    Microsoft Academic Search

    A. Baldan

    2004-01-01

    The factors affecting the mechanical and environmental durability (or stability), and performance of the adhesively bonded joints in various adherends including metallic alloys, polymers and composite materials are studied in detail. The primary function of a joint is to transfer load from one structural member to another. In most bonded joints the load transfer takes place through interfacial shear. At

  14. Stability analysis and robust composite controller synthesis for flexible joint robots

    Microsoft Academic Search

    H. D. Taghirad; M. A. Khosravi

    2006-01-01

    In this paper the control of flexible joint manipulators is studied in detail. The model of N -axis flexible joint manipulators is derived and reformulated in the form of singular perturbation theory and an integral manifold is used to separate fast dynamics from slow dynamics. A composite control algorithm is proposed for the flexible joint robots, which consists of two

  15. Joint IFAS Committee on Tenure, Permanent Status, and Promotion Issues I. Committee Composition

    E-print Network

    Jawitz, James W.

    1 Joint IFAS Committee on Tenure, Permanent Status, and Promotion Issues I. Committee Composition, and promotion packet. Joint committee: 6 in favor; 0 opposed; 0 abstained. IFAS Faculty Assembly: voted in favor with no official teaching appointment. Joint committee: 6 in favor; 0 opposed; 0 abstained. IFAS Faculty Assembly

  16. Ultrasonic inspection of adhesive joints of composite pipelines

    NASA Astrophysics Data System (ADS)

    de Almeidaa, Priscila Duarte; Alcoforado Rebello, João Marcos; Pereira, Gabriela Ribeiro; Soares, Sérgio Damasceno; Fernandez, Roman

    2014-02-01

    Composite pipelines are an attractive solution when traditional materials are not suitable for this purpose, which happens frequently at aggressive environments and also where the structural weight is a limiting factor. This work studies the application of the ultrasonic technique at the detection of defects as lack of adhesive and lack of adhesion, commonly found in adhesive joints of glass fiber reinforced plastic (GFRP) pipelines applied at onshore and offshore facilities. Computational simulations were conducted in CIVA 11software (beta version) in order to obtain the best possible configuration for the inspections, applying the pulse-echo technique. Experimental results were compared to these simulations and several transducers were tested. An inspection methodology and reference blocks were developed for the calibration of the inspections. Some samples were selected for cutting in order to compare the ultrasonic results and the real condition of the joints. Results show that smaller frequencies are suitable for the inspection of this material and focused probes present more accurate results.

  17. Monitoring of Marine Grade Composite Doubler Plate Joints Using Embedded Fiber Optic Strain Sensors

    Microsoft Academic Search

    Rodrigo Silva-Muñoz; Roberto A. Lopez-Anido

    2008-01-01

    The objective of this paper was to develop a methodology for the structural health monitor- ing of composite joints based on strain measurements using distributed embedded fiber optic strain (FOS) sensors of the fiber Bragg grating (FBG) type. Secondary bonded woven E-glass\\/vinyl ester composite doubler plate joints were subjected to fatigue tension loading. The feasibility of monitoring delamination using embedded

  18. Structural health monitoring of marine composite structural joints using embedded fiber Bragg grating strain sensors

    Microsoft Academic Search

    Rodrigo A. Silva-Muñoz; Roberto A. Lopez-Anido

    2008-01-01

    This paper presents a method for the health monitoring of composite joints based on strain measure- ments using distributed embedded fiber Bragg grating (FBG) sensors. Secondary bonded woven E-glass\\/vinyl ester composite doubler plate joints were subjected to fatigue tension loading to induce sta- ble crack propagation. A finite element (FE) model was developed to correlate experimental strain mea- surements prior

  19. Structural health monitoring of marine composite structural joints using embedded fiber Bragg grating strain sensors

    Microsoft Academic Search

    Rodrigo A. Silva-Muñoz; Roberto A. Lopez-Anido

    2009-01-01

    This paper presents a method for the health monitoring of composite joints based on strain measurements using distributed embedded fiber Bragg grating (FBG) sensors. Secondary bonded woven E-glass\\/vinyl ester composite doubler plate joints were subjected to fatigue tension loading to induce stable crack propagation. A finite element (FE) model was developed to correlate experimental strain measurements prior to cyclic loading

  20. Applicability of the crack tip element analysis for damage prediction of composite T-joints

    Microsoft Academic Search

    F. Dharmawan; H. C. H. Li; I. Herszberg; S. John

    2008-01-01

    The expanding application of polymeric composite materials in the Aerospace industry has led to the extension of its application to other industries such as the marine industry. A typical joint between the hull and bulkhead used in a monocoque structure is known as a T-joint. It consists of composite overlaminates over a shaped fillet to allow the transmission of direct

  1. Effects of Different Braze Materials and Composite Substrates on Composite/Ti Joints

    NASA Technical Reports Server (NTRS)

    Morscher, Gregory N.; Singh, Mrityunjay; Asthana, Rajiv; Shpargel, Tarah

    2007-01-01

    An ever increasing number of applications require robust joining technologies of dissimilar materials. In this study, three types of ceramic composites (C-C, C-SiC, and SiC-SiC) were vacuum brazed to commercially pure Ti using the Cusil-ABA (63 Ag - 35.5 Cu - 1.75 Ti) active metal braze alloy. The study also compared composite specimens as-fabricated and after surface grinding/polishing. A butt-strap tensile shear strength test was used to evaluate the joined structures at room temperature, 270 and 500 C. The elevated temperatures represent possible use temperatures for some heat rejection type applications. Joint strength will be discussed in light of braze wetting and spreading properties, composite properties, and test temperature.

  2. Application of Pi Preform Composite Joints in Fabrication of NASA Composite Crew Module Demonstration Structure

    NASA Technical Reports Server (NTRS)

    Higgins, John E.; Pelham, Larry

    2008-01-01

    This paper will describe unique and extensive use of pre-woven and impregnated pi cross-sections in fabrication of a carbon composite demonstration structure for the Composite Crew Module (CCM) Program. The program is managed by the NASA Safety and Engineering Center with participants from ten NASA Centers and AFRL. Multiple aerospace contractors are participating in the design development, tooling and fabrication effort as well. The goal of the program is to develop an agency wide design team for composite habitable spacecraft. The specific goals for this development project are: a) To gain hands on experience in design, building and testing a composite crew module. b) To validate key assumptions by resolving composite spacecraft design details through fabrication and testing of hardware. This paper will focus on the design and fabrication issues supporting selection of the Lockheed Martin patented Pi pre-form to provide sound composite joints a numerous locations in the structure. This abstract is based on Preliminary Design data. The final design will continue to evolve through the fall of 2007 with fabrication mostly completed by conference date.

  3. Evaluation of weldability for resistance spot welded single-lap joint between GA780DP and hot-stamped 22MnB5 steel sheets

    Microsoft Academic Search

    Hong-Seok Choi; Geun-Hwan Park; Woo-Seung Lim; Byung-min Kim

    2011-01-01

    Recently, in the automotive industry, Al-coated boron steel sheets (22MnB5) have been used for hot stamping, and the use of\\u000a these sheets makes it possible to achieve a tensile strength of over 1,500 MPa, since a metallurgical transformation from\\u000a austenite to martensite occurs during the process. In this study, resistance spot welding (RSW) experiments were performed\\u000a in order to evaluate

  4. GUIDED WAVE PROPAGATION THROUGH COMPOSITE BONDED JOINTS Mohammad H. Sherafat1

    E-print Network

    Paris-Sud XI, Université de

    joint, Composite repair, Giuded wave propagation, Structural Health Monitoring(SHM), Disbond detection of specific strength and stiffness, susceptibility to hidden damage in composites is still a major point of concern. These types of damage in composite structures can significantly jeopardize their performance

  5. Microstructure and Mechanical Properties of Joints in Sintered SiC Fiber-Bonded Ceramics Brazed with Ag-Cu-Ti Alloy

    SciTech Connect

    Singh, Mrityunjay [NASA-Glenn Research Center, Cleveland; Matsunaga, Tadashi [ORNL; Lin, Hua-Tay [ORNL; Asthana, Rajiv [University of Wisconsin-Stout, Menomonie; Ishikawa, Toshihiro [Ube Industries, Ltd.

    2012-01-01

    Active metal brazing of a new high thermal conductivity sintered SiC-polycrystalline fiber-bonded ceramic (SA-Tyrannohex{reg_sign}) has been carried out using a Ti-containing Ag-Cu active braze alloy (Cusil-ABA{reg_sign}). The brazed composite joints were characterized using scanning electron microscopy coupled with energy-dispersive X-ray spectrometry (SEM-EDS). The results show that this material can be successfully joined using judiciously selected off-the shelf active braze alloys to yield metallurgically sound joints possessing high integrity. Uniform and continuous joints were obtained irrespective of differences in the fiber orientation in the substrate material. Detailed interfacial microanalysis showed that the titanium reacts with C and Si to form TiC layer and a Ti-Si compound, respectively. Furthermore, the evaluation of shear strength of the joints was also conducted at ambient and elevated temperatures in air using the single-lap offset (SLO) shear test. The perpendicular-type SA-Tyrannohex joints exhibited apparent shear strengths of about 42 MPa and 25 MPa at 650 C and 750 C, respectively. The fracture at the higher temperature occurred at the interface between the reaction-formed TiC layer and braze. This might be caused by generation of stress intensity when a shear stress was applied, according to {mu}-FEA simulation results.

  6. Microstructure and mechanical properties of joints in sintered SiC fiber-bonded ceramics brazed with Ag Cu Ti alloy

    SciTech Connect

    Singh, Mrityunjay [NASA-Glenn Research Center, Cleveland; Asthana, Rajiv [University of Wisconsin-Stout, Menomonie; Ishikawa, Toshihiro [Ube Industries, Ltd.; Matsunaga, Tadashi [Ube Industries, Ltd.; Lin, Hua-Tay [ORNL

    2012-01-01

    Active metal brazing of a new high thermal conductivity sintered SiC-polycrystalline fiber-bonded ceramic (SA-Tyrannohexs) has been carried out using a Ti-containing Ag Cu active braze alloy (Cusil-ABAs). The brazed composite joints were characterized using scanning electron microscopy coupled with energy-dispersive X-ray spectrometry (SEM EDS). The results show that this material can be successfully joined using judiciously selected off-the shelf active braze alloys to yield metallurgically sound joints possessing high integrity. Uniform and continuous joints were obtained irrespective of differences in the fiber orientation in the substrate material. Detailed interfacial microanalysis showed that the titanium reacts with C and Si to form TiC layer and a Ti Si compound, respectively. Furthermore, the evaluation of shear strength of the joints was also conducted at ambient and elevated temperatures in air using the single-lap offset (SLO) shear test. The perpendicular-type SA-Tyrannohex joints exhibited apparent shear strengths of about 42 MPa and 25 MPa at 650 1C and 750 1C, respectively. The fracture at the higher temperature occurred at the interface between the reactionformed TiC layer and braze. This might be caused by generation of stress intensity when a shear stress was applied, according to m-FEA simulation results.

  7. Failure analysis of woven kevlar fiber reinforced epoxy composites pinned joints

    Microsoft Academic Search

    Bülent Murat ?çten; Ramazan Karakuzu; M. Evren Toygar

    2006-01-01

    An investigation was performed to determine the failure mode and the failure load of mechanically fastened joints in woven kevlar epoxy composite plates. Two-dimensional finite element code is developed to predict damage initiation, progression and strength of joints. Hashin, Hoffman and Maximum Stress criteria were used in this failure analysis. Experiments were performed to find the failure load and to

  8. Post-Failure Analysis of Bolted Composite Joints in Tension or Shear-Out Mode Failure

    Microsoft Academic Search

    Fu-Kuo Chang; Kuo-Yen Chang

    1987-01-01

    A progressive damage model was developed for bolted joints in laminated composites which may fail in either tension mode or shear-out mode. The model is capable of assess ing damage accumulated in laminates with arbitrary ply orientations during mechanical loading and of predicting the ultimate strength of the joints which failed in tension or shear-out mode. The model consists of

  9. Damage prediction models for composite T-Joints in marine applications

    Microsoft Academic Search

    F. Dharmawan; S. John; H. C. H. Li; I. Herszberg

    For a monocoque hull structure, the bulkhead is used to separate the hull into many compartments. A typical joint between the hull and bulkhead used in such structure is known as a T- joint. It consists of composite overlaminates over a shaped fillet to allow the transmission of direct and membrane shear stresses. This paper describes the numerical solutions of

  10. THE ROLE OF SCARF ANGLE IN THE PERFORMANCE OF ALUMINUM MATRIX COMPOSITE JOINTS

    Microsoft Academic Search

    D. D. BRINK; C. G. LEVI; A. C. F. COCKS; F. A. LECKIE

    1997-01-01

    The role of geometry on the mechanical performance of scarf joints in Al-matrix composites reinforced with continuous polycrystalline alumina fibers was investigated. Model joints consisting of thin metal interlayers at varying scarf angles between composite sub-elements were designed, manufactured and tested to study the relevant deformation and failure phenomena. Specimens were produced by pressurized infiltration of molten Al-4.5%Mg into fiber

  11. Thermal Effects on the Bearing Behavior of Composite Joints

    NASA Technical Reports Server (NTRS)

    Walker, Sandra Polesky

    2001-01-01

    Thermal effects on the pin-bearing behavior of an IM7/PET15 composite laminate are studied comprehensively. A hypothesis presents factors influencing a change in pin-bearing strength with a change in temperature for a given joint design. The factors include the change in the state of residual cure stress, the material properties, and the fastener fit with a change in temperature. Experiments are conducted to determine necessary lamina and laminate material property data for the IM7/PET15 being utilized in this study. Lamina material properties are determined between the assumed stress free temperature of 460 F down to -200 F. Laminate strength properties are determined for several lay-ups at the operating temperatures of 350 F, 70 F, and -200 F. A three-dimensional finite element analysis model of a composite laminate subject to compressive loading is developed. Both the resin rich layer located between lamina and the thermal residual stresses present in the laminate due to curing are determined to influence the state of stress significantly. Pin-bearing tests of several lay-ups were conducted to develop an understanding on the effect of temperature changes on the pin-bearing behavior of the material. A computational study investigating the factors influencing pin-bearing strength was performed. A finite element model was developed and used to determine the residual thermal cure stresses in the laminate containing a hole. Very high interlaminar stress concentrations were observed two elements away from the hole boundary at all three operating temperatures. The pin-bearing problem was modeled assuming a rigid frictionless pin and restraining only radial displacements at the hole boundary. A uniform negative pressure load was then applied to the straight end of the model. A solution, where thermal residual stresses were combined with the state of stress due to pin-bearing loads was evaluated. The presence of thermal residual stresses intensified the interlaminar stresses predicted at the hole boundary in the pin-bearing problem. This dissertation shows that changes in material properties drives pin-bearing strength degradation with increasing temperature.

  12. A Study of Structural Composite Tee Joints in Small Boats

    Microsoft Academic Search

    R. A. Shenoi; F. L. M. Violette

    1990-01-01

    The paper examines the influence of joint geometry on the ability to transfer out-of-plane loads for a hull bulkhead joint in small boats. The hull bulkhead assemblies have been designed on the basis of sandwich beam and laminated plate theories. An analytical solution has also been developed to predict the failure load. Experimental speci mens have been produced and tested

  13. Torque Limit for Bolted Joint for Composites. Part A; TTTC Properties of Laminated Composites

    NASA Technical Reports Server (NTRS)

    Zhao, Yi

    2003-01-01

    The existing design code for torque limit of bolted joints for composites at Marshall Space Flight Center is MSFC-STD-486B, which was originally developed in 1960s for metallic materials. The theoretical basis for this code was a simplified mechanics analysis, which takes into account only the bolt, nut and washers, but not the structural members to be connected. The assumption was that metallic materials would not fail due to the bearing stress at the contact area between washer and the mechanical member. This is true for metallic materials; but for composite materials the results could be completely different. Unlike most metallic materials, laminated composite materials have superior mechanical properties (such as modulus and strength) in the in-plane direction, but not in the out-of-plane, or through-the-thickness (TTT) direction. During the torquing, TTT properties (particularly compressive modulus and compressive strength) play a dominant role in composite failure. Because of this concern, structural design engineers at Marshall are currently using a compromised empirical approach: using 50% of the torque value for composite members. Companies like Boeing is using a similar approach. An initial study was conducted last summer on this topic to develop theoretical model(s) that takes into consideration of composite members. Two simplified models were developed based on stress failure criterion and strain failure criterion, respective. However, these models could not be used to predict the torque limit because of the unavailability of material data, specifically, through-the-thickness compression (TTTC) modulus and strength. Therefore, the task for this summer is to experimentally determine the TTTC properties. Due to the time limitation, only one material has been tested: IM7/8552 with [0 degrees,plus or minus 45 degrees, 90 degree ] configuration. This report focuses the test results and their significance, while the experimentation will be described in a separate report by Mr. Kris Kostreva.

  14. Design, Fabrication and Test of Graphite/Polyimide Composite Joints and Attachments for Advanced Aerospace Vehicles

    NASA Technical Reports Server (NTRS)

    Cushman, J. B.

    1981-01-01

    Standard and advanced bonded joint concepts were evaluated to develop a data base for the design and analysis of advanced composite joints for use at elevated temperatures (561K (550F)). Design concepts for specific joint applications and the fundamental parameters controlling the static strength characteristics of such joints were identified. Test results are presented for rail shear and sandwich beam compression tests and tension tests of moisture conditioned specimens and bonded on "T" sections. Coefficients of thermal expansion data are presented for A7F (LARC 13 Amide-imide modified) adhesion. Static discriminator test results for type 1 and type 2 bonded and bolted preliminary attachment concepts are presented and discussed.

  15. Critical joints in large composite primary aircraft structures. Volume 1: Technical summary

    NASA Technical Reports Server (NTRS)

    Bunin, Bruce L.

    1985-01-01

    A program was conducted at Douglas Aircraft Company to develop the technology for critical joints in composite wing structure that meets all the design requirements of a 1990 commercial transport aircraft. In fulfilling this objective, analytical procedures for joint design and analysis were developed during Phase 1 of the program. Tests were conducted at the element level to supply the empirical data required for methods development. Large composite multirow joints were tested to verify the selected design concepts and for correlation with analysis predictions. The Phase 2 program included additional tests to provide joint design and analysis data, and culminated with several technology demonstration tests of a major joint area representative of a commercial transport wing. The technology demonstration program of Phase 2 is discussed. The analysis methodology development, structural test program, and correlation between test results and analytical strength predictions are reviewed.

  16. Electromigration performance of Pb-free solder joints in terms of solder composition and joining path

    NASA Astrophysics Data System (ADS)

    Seo, Sun-Kyoung; Kang, Sung K.; Cho, Moon Gi; Lee, Hyuck Mo

    2010-07-01

    The electromigration (EM) performance of Pb-free solder joints is investigated in terms of solder composition (Sn-0.5Cu vs. Sn-1.8Ag) and joining path to Cu vs. Ni(P) under bump metallization (UBM). In the double-sided joints of Ni(P)/solder/Cu, the micro-structure of solder joints and the interfacial intermetallic compound (IMC) layers are significantly affected by solder composition and joining path. The as-reflowed microstructure of Sn-0.5Cu joints consists of small columnar grains with thin IMC layers at both UBM interfaces, independent of the joining path, while Sn-1.8Ag joints have a few large grains of low-angle grain boundaries with thick IMC layers when joined first to Ni(P) UBM, but a few 60° twins with thin IMC layers when joined first to Cu UBM. The EM stressing under high current densities at 150°C reveals that Sn-1.8Ag joints have a superior lifetime compared to Sn-0.5Cu joints. In addition, the EM lifetime of Sn-1.8Ag joints reflowed first on Ni(P) UBM is the longest among four groups of the solder joints examined.

  17. Design, Fabrication, and Characterization of High Temperature Joints in Ceramic Composites

    NASA Technical Reports Server (NTRS)

    Singh, M.

    1999-01-01

    Ceramic joining has been recognized as one of the enabling technologies for the successful utilization of ceramic components in a number of demanding, high temperature applications. Various joint design philosophies and design issues have been discussed along with an affordable, robust ceramic joining technology (ARCJoinT). A wide variety of silicon carbide-based composite materials, in different shapes and sizes, have been joined using this technology. This technique is capable of producing joints with tailorable thickness and composition. The room and high temperature mechanical properties and fractography of ceramic joints have been reported. These joints maintain their mechanical strength up to 1200C in air. This technology is suitable for the joining of large and complex shaped ceramic composite components and with certain modifications, can be applied to repair of ceramic components damaged in service.

  18. Structural testing of the North Wind 250 composite rotor joint

    SciTech Connect

    Musial, W; Link, H [National Renewable Energy Lab., Golden, CO (United States); Coleman, C [Northern Power Systems, Moretown, VT (United States)

    1994-05-01

    The North Wind 250 wind turbine is under development at Northern Power Systems (NPS) in Moretown, VT. The turbine uses a unique, flow-through, teetered-rotor design. This design eliminates structural discontinuities at the blade/hub interface by fabricating the rotor as one continuous structural element. To accomplish this, the two blade spars are joined at the center of the rotor using a proprietary bonding technique. Fatigue tests were conducted on the full-scale rotor joint at the National Renewable Energy Laboratory (NREL). Subsequent tests are now underway to test the full-scale rotor and hub assembly to verify the design assumptions. The test articles were mounted in dedicated test fixtures. For the joint test, a constant moment was generated across the joint and parent material. Hydraulic actuators applied sinusoidal loading to the test article at levels equivalent to 90% of the extreme wind load for over one million cycles. When the loading was increased to 112% of the extreme wind load, the joint failed by buckling. Strain levels were monitored at 14 locations inside and outside of the blade joint during the test. The tests were used to qualify this critical element of the rotor for field testing and to provide information needed to improve the structural design of the joint.

  19. The influence of adhesive composition on mechanical and electrical properties of joints between SMDs and PCBs

    Microsoft Academic Search

    Ryszard Kisiel

    2000-01-01

    The main goal of this paper is to establish how conductive adhesive composition will influence the electrical and mechanical properties of joints between SMDs and PCBs. Eight conductive adhesive compositions were investigated. The design of experiments methodology based on Taguchi orthogonal array was applied to compose the best adhesive properties for SMT. Two types of polymer matrix were applied. Two

  20. Laser ablation assisted adhesive bonding of automotive structural composites

    SciTech Connect

    Boeman, R.G.; Paulauskas, F.L.; Warren, C.D.

    1999-07-03

    Laser ablation has been evaluated as a surface pretreatment prior to adhesive bonding. In prior experimental work, it was observed that when adhesively bonded, composite, single lap shear samples fail, the fracture often occurs at either the adhesive/adherend interface or in the resin rich surface layer of the composite. These two areas represent the weakest portion of the joint. Laser ablation pretreatment generates areas where the resin on the composite surface is selectively removed leaving behind exposed reinforcing fibers which are the major load bearing members of the composite. In a subsequent adhesive bonding operation, this allows portions of the fibers to be encapsulated in the adhesive while other portions of the fiber remain in the composite resin. This type of pretreatment permits fibers to bridge and reinforce the interface between adhesive and adherend. A secondary benefit is the removal of surface contaminantes by pyrolysis. Microscopic observation of laser ablated surfaces indicates a prominent, fiber rich area. Results of the mechanical evaluation indicated that the lap shear strength for laser ablated samples was significantly higher than specimens with no pretreatment or with solvent cleaning only, but were slightly lower than specimens that were mechanically roughened and cleaned with solvents prior to bonding.

  1. Time and Temperature-Dependent Failures of a Metal-to-Composites Bonded Joint with PMMA Adhesive Material

    Microsoft Academic Search

    Sangwook Sihn; Yasushi Miyano; Masayuki Nakada; Stephen W. Tsai

    2003-01-01

    A metal–composite bonded joint with a PMMA adhesive material was fabricated and tested under various loading conditions to help a short-term and long-term design of the bonded-jointed structures. The bonded joint is composed of a cast-iron rod and a GFRP composite pipe as adherends, and ductile PMMA as adhesive material (Plexus AO425). Tubular-lap bonded joints were fabricated conveniently and consistently

  2. Critical joints in large composite primary aircraft structures. Volume 2: Technology demonstration test report

    NASA Technical Reports Server (NTRS)

    Bunin, Bruce L.

    1985-01-01

    A program was conducted to develop the technology for critical structural joints in composite wing structure that meets all the design requirements of a 1990 commercial transport aircraft. The results of four large composite multirow bolted joint tests are presented. The tests were conducted to demonstrate the technology for critical joints in highly loaded composite structure and to verify the analytical methods that were developed throughout the program. The test consisted of a wing skin-stringer transition specimen representing a stringer runout and skin splice on the wing lower surface at the side of the fuselage attachment. All tests were static tension tests. The composite material was Toray T-300 fiber with Ciba-Geigy 914 resin in 10 mil tape form. The splice members were metallic, using combinations of aluminum and titanium. Discussions are given of the test article, instrumentation, test setup, test procedures, and test results for each of the four specimens. Some of the analytical predictions are also included.

  3. Thermal-mechanical fatigue test apparatus for metal matrix composites and joint attachments

    Microsoft Academic Search

    L. J. Westfall; D. W. Petrasek

    1985-01-01

    Two thermal-mechanical fatigue (TMF) test facilities were designed and developed, one to test tungsten fiber reinforced metal matrix composite specimens at temperature up to 1430C (2600F) and another to test composite\\/metal attachment bond joints at temperatures up to 760C (1400 F). The TMF facility designed for testing tungsten fiber reinforced metal matrix composites permits test specimen temperature excursions from room

  4. Experimental determination of the effects of moisture on composite-to-composite adhesive joints

    NASA Technical Reports Server (NTRS)

    Deiasi, R. J.; Schulte, R. L.

    1981-01-01

    The primary mode of moisture ingress into bonded composite joints is determined using a nuclear probe for deuterium (NPD) to measure the localized D2O content along the length of the adhesive (FM-300 and EA-9601) and through the thickness of bonded composite speciments. Calculated diffusivities and NPD measured equilibrium moisture contents are used to predict the moisture profiles along the length of the adhesives as a function of exposure time, temperature, and relative humidity. These results are compared with the observed moisture profiles to evaluate the extent of enhanced edge diffusion. The FM-300 adhesive exhibits good agreement between measured and predicted profiles at 49 C, 70% and 90% RH, and 77 C, 70% RH. At 77 C, 90% RH, the measured moisture content near the adhesive edge is substantially larger than the predicted level. The EA-9601 adhesive also shows good agreement at 49 C, 70% and 90% RH, but at 77 C, the concentration of D20 near the edges is enhanced at each humidity level. The effect of moisture content on the bond shear strength at room temperature and at elevated temperature is evaluated.

  5. The role of scarf angle in the performance of aluminum matrix composite joints

    SciTech Connect

    Brink, D.D.; Levi, C.G.; Cocks, A.C.F.; Leckie, F.A. [Univ. of California, Santa Barbara, CA (United States)] [Univ. of California, Santa Barbara, CA (United States)

    1997-07-01

    The role of geometry on the mechanical performance of scarf joints in Al-matrix composites reinforced with continuous polycrystalline alumina fibers was investigated. Model joints consisting of thin metal interlayers at varying scarf angles between composite sub-elements were designed, manufactured and tested to study the relevant deformation and failure phenomena. Specimens were produced by pressurized infiltration of molten Al-4.5%Mg into fiber preforms containing prescribed discontinuities. In this way, matrix continuity through the interlayer was ensured and defects normally introduced in actual joining operations were minimized. Reference composite specimens were produced in the same actual joining operations were minimized. Reference composite specimens were produced in the same manner and exhibited tensile strengths of the order of 700 MPa, compared with a matrix yield strength, {sigma}{sub 0}, of approximately 100 MPa. The strength of the scarf joints with aspect ratios of 17--48 and angles below 45{degree} was relatively constant, {approximately}310 {+-} 10 MPa, but increased at higher angles, reaching over 485 MPa at 75{degree}. Failure of these joints was typically by debonding at the composite-interlayer interface. A simple analytical model suggests that failure occurs when the stress normal to the interlayer reaches a critical value, although the details of the debonding mechanism are still unclear. Conditions leading to a transition from debond failure to plastic collapse in joints of low aspect ratios are also discussed.

  6. Adhesive strength and tensile fracture of Ni particle enhanced Sn–Ag composite solder joints

    Microsoft Academic Search

    H. T. Lee; Y. H. Lee

    2006-01-01

    This study forms composite solders by adding 0.5–3wt% of Ni particles in situ to Sn–3.5wt%Ag lead-free solder. Cu\\/solder\\/Cu specimens are prepared by dipping two Cu rods into a solder bath to produce a solder joint. Some of the joint specimens are retained in the as-soldered condition, while the others are aged at 150°C for 100, 200, 400, or 500h, respectively.

  7. Three-dimensional contact stress analysis of a composite laminate with bolted joint

    Microsoft Academic Search

    Wen-Hwa Chen; Shyh-Shiaw Lee; Jyi-Tyan Yeh

    1995-01-01

    Based on an incremental restricted variational principle formulated and the transformation matrix derived from three-dimensional contact kinematic conditions, a general but effective finite element technique satisfying various contact conditions is established for the three-dimensional contact stress analysis of a composite laminate with bolted joint. The double-lap bolted joint in the thin graphite\\/epoxy laminate of [450\\/–4590]s lay-up or in the thick

  8. CFRP\\/titanium hybrid material for improving composite bolted joints

    Microsoft Academic Search

    B. Kolesnikov; L. Herbeck; A. Fink

    2008-01-01

    The structural joining remains an essential challenge for the development of composite aerospace structures: every structural interconnection means a disturbance of an optimized structure resulting in an increase in overall structural weight. The lightweight potential of advanced, high-performance fiber composite materials is affected more strongly by mechanical fastening techniques than by conventional metallic materials due to the low shear and

  9. Bearing-Bypass Loading On Bolted Composite Joints

    NASA Technical Reports Server (NTRS)

    Crews, John H.; Naik, Rajiv-Vikas A.

    1989-01-01

    Unexpected interaction between effects of bypass and bearing loads reported. Combined experimental and analytical study described in NASA technical memorandum conducted to investigate effects of simultaneous bearing and bypass loading on graphite/epoxy laminate. Results important in emerging technology of composites for use in wide range of applications. Includes applications in aircraft, boats, and automobiles, in which bolted connections to composites increasingly important.

  10. Fatigue properties of jointed wood composites Part I Statistical analysis, fatigue master curves and constant life diagrams

    Microsoft Academic Search

    I. P. Bond; M. P. Ansell

    1998-01-01

    The primary aim of this work was to assess the fatigue performance of scarf-jointed laminated wood composites used to manufacture wind turbine blades and establish simple fatigue design procedures. Laminates made from poplar (Populus canadensis\\/serotina), Khaya (Khaya ivorensis) and beech (Fagus sylvatica), incorporating typical scarf joints, were assessed under reversed loading (R =-1). Scarf joints were found to be great

  11. Thermal-Stress Reducer For Metal/Composite Joint

    NASA Technical Reports Server (NTRS)

    Glinski, Robert L.

    1993-01-01

    Simple insert called "thermal link" reduces stresses caused by mismatches between thermal expansions of metal part and nonmetallic part made of fiber/matrix composite material. Link conceived for use in casing of advanced jet engine.

  12. Structural Performance Evaluation of Composite-To-Steel Weld Bonded Joint

    SciTech Connect

    Shah, Bhavesh [General Motors Corporation-R& D; Frame, Barbara J [ORNL; Dove, Caroline [ACC, USCAR; Fuchs, Hannes [Multimatic Engineering

    2010-01-01

    The Automotive Composites Consortium (ACC), a collaboration of Chrysler, Ford, General Motors, and the US Department of Energy is conducting a focal project to demonstrate the use of composite materials in high volume structural applications such as an underbody capable of carrying crash loads. One of the critical challenges is to attach the composite part to the steel structure in a high-volume automotive manufacturing environment and meet the complex requirements for crash. Weld-bonding, a combination of adhesive bonding and spot welding, was selected as the primary joining method. A novel concept of bonding doubler steel strips to composite enabled the spot welding to the steel structure, ensuring the compability with the OEM assembly processes. The structural performance of the joint, including durability, was assessed via analytical and physical testing under quasi-static loading at various temperatures. This paper discusses the results of the experiments designed to generate key modeling parameters for Finite Element Analysis of the joint.

  13. Ultimate strength of high-load-capacity composite bolted joints

    NASA Technical Reports Server (NTRS)

    Hyer, M. W.; Lightfoot, M. C.

    1979-01-01

    Presented are the results of a series of tests initiated to obtain baseline data on the load-carrying capacity of bolted joints designed to carry large loads, specifically up to 222 kN (50 kips). The major testing purposes were to determine the load carrying capacity as a function of the width and thickness of the joint and the diameter and number of bolts, and to observe the failure mode. A total of 100 tests were conducted on three different specimen configurations. The specimens were fabricated from a T300/5208 fiber/resin system in a quasi-isotropic lay-up. The results presented indicate that for a given ratio of specimen width to hole diameter, the specimens with the smaller holes sustained a higher net-section tensile stress before failure. In addition, for a given ratio of specimen width to hole diameter, the thinner specimens withstood a higher net-section stress. No attempt has been made to correlate the results with theoretical predictions.

  14. Mechanical behavior of a glass-fiber reinforced composite to steel joint for ships

    NASA Astrophysics Data System (ADS)

    Li, Xiaowen; Li, Ping; Lin, Zhuang; Yang, Dongmei

    2015-03-01

    The use of a glass-fiber reinforced composite in marine structures is becoming more common, particularly due to the potential weight savings. The mechanical response of the joint between a glass-fiber reinforced polymer (GRP) superstructure and a steel hull formed is examined and subsequently modified to improve performance through a combined program of modeling and testing. A finite-element model is developed to predict the response of the joint. The model takes into account the contact at the interface between different materials, progressive damage, large deformation theory, and a non-linear stress-strain relationship. To predict the progressive failure, the analysis combines Hashin failure criteria and maximum stress failure criteria. The results show stress response has a great influence on the strength and bearing of the joint. The Balsawood-steel interface is proved to be critical to the mechanical behavior of the joint. Good agreement between experimental results and numerical predictions is observed.

  15. Fatigue analysis of thin AlMgSi welded joints under constant and variable amplitude block loadings

    Microsoft Academic Search

    J. A. M Pinho-da-Cruz; J. A. M Ferreira; J. D. M Costa; L. F. P Borrego

    2003-01-01

    This paper reports the fatigue behaviour of thin AlMgSi1 aluminium alloy weldments and the improvement in fatigue strength due to post-weld treatments. Several fatigue tests were performed using two distinct types of thin welded joints, T and single lap, manufactured using a 6xxx series aluminium alloy, and the efficiency of fatigue life improvement techniques, such as post-weld heat treatment and

  16. Static and Fatigue Strength Evaluations for Bolted Composite/Steel Joints for Heavy Vehicle Chassis Components

    SciTech Connect

    Sun, Xin; Stephens, Elizabeth V.; Herling, Darrell R.

    2004-09-14

    In May 2003, ORNL and PNNL began collaboration on a four year research effort focused on developing joining techniques to overcome the technical issues associated with joining lightweight materials in heavy vehicles. The initial focus of research is the development and validation of joint designs for a composite structural member attached to a metal member that satisfy the structural requirements both economically and reliably. Huck-bolting is a common joining method currently used in heavy truck chassis structures. The initial round of testing was conducted to establish a performance benchmark by evaluating the static and fatigue behavior of an existing steel/steel chassis joint at the single huck-bolt level. Both tension and shear loading conditions were considered, and the resulting static and fatigue strengths will be used to guide the joint design for a replacement composite/steel joint. A commercially available, pultruded composite material was chosen to study the generic issues related to composite/steel joints. Extren is produced by STRONGWELL, and it is a combination of fiberglass reinforcement and thermosetting polyester or vinyl ester resin systems. Extren sheets of 3.2 mm thick were joined to 1.4 mm SAE1008 steel sheets with a standard grade 5 bolt with 6.35 mm diameter. Both tension and shear loading modes were considered for the single hybrid joint under static and fatigue loading conditions. Since fiberglass reinforced thermoset polymer composites are a non-homogenous material, their strengths and behavior are dependent upon the design of the composite and reinforcement. The Extren sheet stock was cut along the longitudinal direction to achieve maximum net-section strength. The effects of various manufacturing factors and operational conditions on the static and fatigue strength of the hybrid joint were modeled and experimentally verified. It was found that loading mode and washer size have significant influence on the static and fatigue strength of the hybrid joint. The effect of different fatigue test frequencies on the sample temperature and the resulting fatigue life was also examined.

  17. Mechanical Performance and Parameter Sensitivity Analysis of 3D Braided Composites Joints

    PubMed Central

    Wu, Yue; Nan, Bo; Chen, Liang

    2014-01-01

    3D braided composite joints are the important components in CFRP truss, which have significant influence on the reliability and lightweight of structures. To investigate the mechanical performance of 3D braided composite joints, a numerical method based on the microscopic mechanics is put forward, the modeling technologies, including the material constants selection, element type, grid size, and the boundary conditions, are discussed in detail. Secondly, a method for determination of ultimate bearing capacity is established, which can consider the strength failure. Finally, the effect of load parameters, geometric parameters, and process parameters on the ultimate bearing capacity of joints is analyzed by the global sensitivity analysis method. The results show that the main pipe diameter thickness ratio ?, the main pipe diameter D, and the braided angle ? are sensitive to the ultimate bearing capacity N. PMID:25121121

  18. Lamb wave propagation in a restricted geometry composite pi-joint specimen

    NASA Astrophysics Data System (ADS)

    Blackshire, James L.; Soni, Som

    2012-05-01

    The propagation of elastic waves in a material can involve a number of complex physical phenomena, resulting in both subtle and dramatic effects on detected signal content. In recent years, the use of advanced methods for characterizing and imaging elastic wave propagation and scattering processes has increased, where for example the use of scanning laser vibrometry and advanced computational models have been used very effectively to identify propagating modes, scattering phenomena, and damage feature interactions. In the present effort, the propagation of Lamb waves within a narrow, constrained geometry composite pi-joint structure are studied using 3D finite element models and scanning laser vibrometry measurements, where the effects of varying sample thickness, complex joint curvatures, and restricted structure geometries are highlighted, and a direct comparison of computational and experimental results are provided for simulated and realistic geometry composite pi-joint samples.

  19. Measurement of damping of graphite epoxy composite materials and structural joints

    NASA Technical Reports Server (NTRS)

    Crocker, Malcolm J.; Rao, Mohan D.; Raju, P. K.; Yan, Xinche

    1989-01-01

    The damping capacity of graphite epoxy materials and structural joints was evaluated. The damping ratio of different composite specimens and bonded joints were systematically evaluated under normal atmospheric conditions and in a vacuum environment. Free and forced vibration test methods were employed for measuring the damping ratios. The effect of edge support conditions on the damping value of a composite tube specimen was studied by using a series of experiments performed on the specimen with different edge supports. It was found that simulating a free-free boundary conditions by having no constraints at the ends gives the lowest value of the material damping of the composite. The accuracy of the estimation of the damping ratio value was improved by using a curve-fitting technique on the response data obtained through measurement. The effect of outgassing (moisture desorption) on the damping capacity was determined by measuring the damping ratio of the tube specimen in a vacuum environment before and after outgassing had occurred. The effects of high and low temperatures on the damping was also investigated by using a series of experiments on tube and beam specimens. An analytical model to study the vibrations of a bonded lap joint system was formulated. Numerical results were generated for different overlap ratios of the system. These were compared with experimental results. In order to determine the influence of bonded joints on the material damping capacity, experiments were conducted on bonded lap-jointed and double-butt-jointed specimens. These experimental results were compared with simple beam specimens with no joints.

  20. Health monitoring of marine composite structural joints using fibre optic sensors

    Microsoft Academic Search

    H. C. H. Li; I. Herszberg; C. E. Davis; A. P. Mouritz; S. C. Galea

    2006-01-01

    This paper describes a methodology for the health monitoring of composite marine joint structures based on strain measurements under operational loading using embedded fibre Bragg grating sensors. Finite element modelling indicated that the presence of a disbond significantly altered the bond-line longitudinal strain distribution. This was verified qualitatively through an experimental test program. The experimental results are examined in relation

  1. Loaded carbon composite scarf joints subject to impact

    Microsoft Academic Search

    Stefanie Feih; Andrew J. Gunnion; Henry C. H. Li; Israel Herszberg

    Bonded composite scarf repairs are often used when a flush surface is required for aerodynamic or stealth reasons. Such repairs on the external surface of an aircraft are subject to the same impact risk as that of the parent structure. Consequently, it is essential to assess their durability in the case of impact. A previous preliminary experimental study found an

  2. Parametric study of scarf joints in composite structures

    Microsoft Academic Search

    Andrew J. Gunnion; Israel Herszberg

    2006-01-01

    Bonded scarf or stepped repairs are used in composite structures when high strength recovery is needed or when there is a requirement for a flush surface to satisfy aerodynamic or stealth requirements. Scarf repairs are complex to design and require the removal of significant parent structure, particularly for thick skins.A parametric finite element (FE) model has been developed to allow

  3. SIMULATION OF PROGRESSIVE DAMAGE IN BOLTED COMPOSITE JOINTS

    Microsoft Academic Search

    Hannes Koerber; Pedro P. Camanho

    Recently, a continuum based progressive damage model for fiber-reinforced composites became available in the commercial finite element code ABAQUS. The implemented model uses the Hashin damage initiation criteria (1,2) and damage evolution is based on the work of Matzenmiller (3) and Camanho and Davila (4). The \\

  4. Disbond monitoring in adhesive joints using shear stress optical fiber sensors

    NASA Astrophysics Data System (ADS)

    Sulejmani, Sanne; Sonnenfeld, Camille; Geernaert, Thomas; Luyckx, Geert; Mergo, Pawel; Urbanczyk, Waclaw; Chah, Karima; Thienpont, Hugo; Berghmans, Francis

    2014-07-01

    We present dedicated shear stress optical fiber sensors for in situ disbond monitoring of adhesive bonds. The shear stress sensitivity of these sensors is about 60 pm MPa-1, which corresponds to a shear strain sensing resolution of 50 ??. By integrating a combination of three such sensors in the adhesive bond line of a single lap joint, we can assess the internal shear stress distribution when the joint is tensile loaded. Disbonding of this joint was initiated by cyclic tensile loading, and the sensor responses were monitored during this process. Our results show that this sensing system can detect disbonds as small as 100 ?m.

  5. Design, fabrication, installation and flight service evaluation of a composite cargo ramp skin on a model CH-53 helicopter

    NASA Technical Reports Server (NTRS)

    Lowry, D. W.; Rich, M. J.

    1983-01-01

    The installation of a composite skin panel on the cargo ramp of a CH-530 marine helicopter is discussed. The composite material is of Kevlar/Epoxy (K/E) which replaces aluminum outer skins on the aft two bays of the ramp. The cargo ramp aft region was selected as being a helicopter airframe surface subjected to possible significant field damage and would permit an evaluation of the long term durability of the composite skin panel. A structural analysis was performed and the skin shears determined. Single lap joints of K/E riveted to aluminum were statically tested. The joint tests were used to determine bearing allowables and the required K/E skin gage. The K/E skin panels riveted to aluminum edge members were tested in a shear fixture to confirm the allowable shear and bearing strengths. Impact tests were conducted on aluminum skin panels to determine energy level and damage relationship. The K/E skin panels of various ply orientations and laminate thicknesses were then impacted at similar energy levels. The results of the analysis and tests were used to determine the required K/E skin gages in each of the end two bays of the ramp.

  6. Loading Analysis of Composite Wind Turbine Blade for Fatigue Life Prediction of Adhesively Bonded Root Joint

    NASA Astrophysics Data System (ADS)

    Salimi-Majd, Davood; Azimzadeh, Vahid; Mohammadi, Bijan

    2015-06-01

    Nowadays wind energy is widely used as a non-polluting cost-effective renewable energy resource. During the lifetime of a composite wind turbine which is about 20 years, the rotor blades are subjected to different cyclic loads such as aerodynamics, centrifugal and gravitational forces. These loading conditions, cause to fatigue failure of the blade at the adhesively bonded root joint, where the highest bending moments will occur and consequently, is the most critical zone of the blade. So it is important to estimate the fatigue life of the root joint. The cohesive zone model is one of the best methods for prediction of initiation and propagation of debonding at the root joint. The advantage of this method is the possibility of modeling the debonding without any requirement to the remeshing. However in order to use this approach, it is necessary to analyze the cyclic loading condition at the root joint. For this purpose after implementing a cohesive interface element in the Ansys finite element software, one blade of a horizontal axis wind turbine with 46 m rotor diameter was modelled in full scale. Then after applying loads on the blade under different condition of the blade in a full rotation, the critical condition of the blade is obtained based on the delamination index and also the load ratio on the root joint in fatigue cycles is calculated. These data are the inputs for fatigue damage growth analysis of the root joint by using CZM approach that will be investigated in future work.

  7. Cohesive Laws and Progressive Damage Analysis of Composite Bonded Joints, a Combined Numerical/Experimental Approach

    NASA Technical Reports Server (NTRS)

    Girolamo, Donato; Davila, Carlos G.; Leone, Frank A.; Lin, Shih-Yung

    2015-01-01

    The results of an experimental/numerical campaign aimed to develop progressive damage analysis (PDA) tools for predicting the strength of a composite bonded joint under tensile loads are presented. The PDA is based on continuum damage mechanics (CDM) to account for intralaminar damage, and cohesive laws to account for interlaminar and adhesive damage. The adhesive response is characterized using standard fracture specimens and digital image correlation (DIC). The displacement fields measured by DIC are used to calculate the J-integrals, from which the associated cohesive laws of the structural adhesive can be derived. A finite element model of a sandwich conventional splice joint (CSJ) under tensile loads was developed. The simulations, in agreement with experimental tests, indicate that the model is capable of predicting the interactions of damage modes that lead to the failure of the joint.

  8. Delamination-Debond Behaviour of Composite T- Joints in Wind Turbine Blades

    NASA Astrophysics Data System (ADS)

    Gulasik, H.; Coker, D.

    2014-06-01

    Wind turbine industry utilizes composite materials in turbine blade structural designs because of their high strength/stiffness to weight ratio. T-joint is one of the design configurations of composite wind turbine blades. T-joints consist of a skin panel and a stiffener co-bonded or co-cured together with a filler material between them. T-joints are prone to delaminations between skin/stiffener plies and debonds between skin-stiffener-filler interfaces. In this study, delamination/debond behavior of a co-bonded composite T-joint is investigated under 0° pull load condition by 2D finite element method. Using Abaqus® commercial FE software, zero-thickness cohesive elements are used to simulate delamination/debond in ply interfaces and bonding lines. Pulling load at 0° is applied and load-displacement behavior and failure scenario are observed. The failure sequence consists of debonding of filler/stringer interface during one load drop followed by a second drop in which the 2nd filler/stringer debonds, filler/skin debonding and skin delamination leading to total loss of load carrying capacity. This type of failure initiation has been observed widely in the literature. When the debond strength is increased 30%, failure pattern is found to change in addition to increasing the load capacity by 200% before total loss of loading carrying capacity occurs. Failure initiation and propagation behavior, initial and max failure loads and stress fields are affected by the property change. In all cases mixed-mode crack tip loading is observed in the failure initiation and propagation stages. In this paper, the detailed delamination/debonding history in T-joints is predicted with cohesive elements for the first time.

  9. Multitechnique monitoring of fatigue damage in adhesively bonded composite lap-joints

    NASA Astrophysics Data System (ADS)

    Karpenko, Oleksii; Koricho, Ermias; Khomenko, Anton; Dib, Gerges; Haq, Mahmoodul; Udpa, Lalita

    2015-03-01

    The requirement for reduced structural weight has driven the development of adhesively bonded joints. However, a major issue preventing their full acceptance is the initiation of premature failure in the form of a disbond between adherends, mainly due to fatigue, manufacturing flaws or impact damage. This work presents the integrated approach for in-situ monitoring of degradation of the adhesive bond in the GFRP composite lap-joint using ultrasonic guided waves and dynamic measurements from strategically embedded FBG sensors. Guided waves are actuated with surface mounted piezoelectric elements and mode tuning is used to provide high sensitivity to the degradation of the adhesive layer parameters. Composite lap-joints are subjected to fatigue loading, and data from piezoceramic transducers are collected at regular intervals to evaluate the progression of damage. Results demonstrate that quasi-static loading affects guided wave measurements considerably, but FBG sensors can be used to monitor the applied load levels and residual strains in the adhesive bond. The proposed technique shows promise for determining the post-damage stiffness of adhesively bonded joints.

  10. Bolted Double-Lap Composite Joints Under Mechanical and Thermal Loading

    NASA Technical Reports Server (NTRS)

    Kradinov, V.; Barut, A.; Madenci, E.; Walker, Sandra P. (Technical Monitor)

    2000-01-01

    This study concerns the determination of the contact stresses and contact region around bolt holes and the bolt load distribution in single- and double-lap joints of composite laminates with arbitrarily located bolts under general mechanical loading conditions and uniform temperature change. The unknown contact stress distribution and contact region between the bolt and laminates and the interaction among the bolts require the bolt load distribution, as well as the contact stresses, to be as part of the solution. The present method is based on the complex potential theory and the variational formulation in order to account for bolt stiffness, bolt-hole clearance, and finite geometry of the composite laminates.

  11. Standard Guide for Acousto-Ultrasonic Assessment of Composites, Laminates, and Bonded Joints

    E-print Network

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 This guide explains the rationale and basic technology for the acousto-ultrasonic (AU) method. Guidelines are given for nondestructive evaluation (NDE) of flaws and physical characteristics that influence the mechanical properties and relative strength of composite structures (for example, filament-wound pressure vessels), adhesive bonds (for example, joints between metal plates), and interlaminar and fiber/matrix bonds in man-made composites and natural composites (for example, wood products). 1.2 This guide covers technical details and rules that must be observed to ensure reliable and reproducible quantitative AU assessments of laminates, composites, and bonded structures. The underlying principles, prototype apparatus, instrumentation, standardization, examination methods, and data analysis for such assessments are covered. Limitations of the AU method and guidelines for taking advantage of its capabilities are cited. 1.3 The objective of AU is to assess subtle flaws and associated strength variatio...

  12. Dynamic measurement of inside strain distributions in adhesively bonded joints by embedded fiber Bragg grating sensor

    NASA Astrophysics Data System (ADS)

    Murayama, Hideaki; Ning, Xiaoguang; Kageyama, Kazuro; Wada, Daichi; Igawa, Hirotaka

    2014-05-01

    Long-length fiber Bragg grating (FBG) with the length of about 100 mm was embedded onto the surface of a carbon fiber reinforced plastics (CFRP) substrate and two CFRP adherends were joined by adhesive to form an adhesive bonded single-lap joint. The joint was subjected to 0.5 Hz cyclic tensile load and longitudinal strain distributions along FBG were measured at 5 Hz by the fiber-optic distributed sensing system based on optical frequency domain reflectometry (OFDR). We could successfully monitor the strain distributions accurately with high spatial resolution of around 1 mm.

  13. Design, fabrication and test of graphite/polyimide composite joints and attachments. [spacecraft control surfaces

    NASA Technical Reports Server (NTRS)

    Cushman, J. B.; Mccleskey, S. F.; Ward, S. H.

    1982-01-01

    The design, analysis, and testing performed to develop four types of graphite/polyimide (Gr/PI) bonded and bolted composite joints for lightly loaded control surfaces on advanced space transportation systems that operate at temperatures up to 561 K (550 F) are summarized. Material properties and small specimen tests were conducted to establish design data and to evaluate specific design details. Static discriminator tests were conducted on preliminary designs to verify structural adequacy. Scaled up specimens of the final joint designs, representative of production size requirements, were subjected to a series of static and fatigue tests to evaluate joint strength. Effects of environmental conditioning were determined by testing aged (125 hours at 589 K (600 F)) and thermal cycled (116 K to 589 K (-250 F to 600 F), 125 times) specimens. It is concluded Gr/PI joints can be designed and fabricated to carry the specified loads. Test results also indicate a possible resin loss or degradation of laminates after exposure to 589 K (600 F) for 125 hours.

  14. Damage prognosis of adhesively-bonded joints in laminated composite structural components of unmanned aerial vehicles

    SciTech Connect

    Farrar, Charles R [Los Alamos National Laboratory; Gobbato, Maurizio [UCSD; Conte, Joel [UCSD; Kosmatke, John [UCSD; Oliver, Joseph A [UCSD

    2009-01-01

    The extensive use of lightweight advanced composite materials in unmanned aerial vehicles (UAVs) drastically increases the sensitivity to both fatigue- and impact-induced damage of their critical structural components (e.g., wings and tail stabilizers) during service life. The spar-to-skin adhesive joints are considered one of the most fatigue sensitive subcomponents of a lightweight UAV composite wing with damage progressively evolving from the wing root. This paper presents a comprehensive probabilistic methodology for predicting the remaining service life of adhesively-bonded joints in laminated composite structural components of UAVs. Non-destructive evaluation techniques and Bayesian inference are used to (i) assess the current state of damage of the system and, (ii) update the probability distribution of the damage extent at various locations. A probabilistic model for future loads and a mechanics-based damage model are then used to stochastically propagate damage through the joint. Combined local (e.g., exceedance of a critical damage size) and global (e.g.. flutter instability) failure criteria are finally used to compute the probability of component failure at future times. The applicability and the partial validation of the proposed methodology are then briefly discussed by analyzing the debonding propagation, along a pre-defined adhesive interface, in a simply supported laminated composite beam with solid rectangular cross section, subjected to a concentrated load applied at mid-span. A specially developed Eliler-Bernoulli beam finite element with interlaminar slip along the damageable interface is used in combination with a cohesive zone model to study the fatigue-induced degradation in the adhesive material. The preliminary numerical results presented are promising for the future validation of the methodology.

  15. Probabilistic Simulation of Progressive Fracture in Bolted-Joint Composite Laminates

    NASA Technical Reports Server (NTRS)

    Minnetyan, L.; Singhal, S. N.; Chamis, C. C.

    1996-01-01

    This report describes computational methods to probabilistically simulate fracture in bolted composite structures. An innovative approach that is independent of stress intensity factors and fracture toughness was used to simulate progressive fracture. The effect of design variable uncertainties on structural damage was also quantified. A fast probability integrator assessed the scatter in the composite structure response before and after damage. Then the sensitivity of the response to design variables was computed. General-purpose methods, which are applicable to bolted joints in all types of structures and in all fracture processes-from damage initiation to unstable propagation and global structure collapse-were used. These methods were demonstrated for a bolted joint of a polymer matrix composite panel under edge loads. The effects of the fabrication process were included in the simulation of damage in the bolted panel. Results showed that the most effective way to reduce end displacement at fracture is to control both the load and the ply thickness. The cumulative probability for longitudinal stress in all plies was most sensitive to the load; in the 0 deg. plies it was very sensitive to ply thickness. The cumulative probability for transverse stress was most sensitive to the matrix coefficient of thermal expansion. In addition, fiber volume ratio and fiber transverse modulus both contributed significantly to the cumulative probability for the transverse stresses in all the plies.

  16. Influence of the properties of externally bonded CFRP on the shear behavior of concrete\\/composite adhesive joints

    Microsoft Academic Search

    E. Ferrier; M. Quiertant; K. Benzarti; P. Hamelin

    2010-01-01

    This paper concerns the strengthening of concrete structures with externally bonded composite reinforcement, and focuses mainly on the influence of the FRP characteristics on the mechanical behavior of the composite to concrete interface. An experimental investigation was conducted, based on the characterization of such bonded assemblies and using a double lap joint shear test. Twelve different series of specimens were

  17. Finite Element Analysis of Composite Joint Configurations with Gaps and Overlaps

    NASA Technical Reports Server (NTRS)

    Krueger, Ronald

    2014-01-01

    The goal of the current study is to identify scenarios for which thermal and moisture effects become significant in the loading of a composite structure. In the current work, a simple configuration was defined, and material properties were selected. A Fortran routine was created to automate the mesh generation process. The routine was used to create the models for the initial mesh refinement study. A combination of element length and width suitable for further studies was identified. Also, the effect of the overlap length and gap length on computed shear and through-thickness stresses along the bondline of the joints was studied for the mechanical load case. Further, the influence of neighboring gaps and overlaps on these joint stresses was studied and was found to be negligible. The results suggest that for an initial study it is sufficient to focus on one configuration with fixed overlap and gap lengths to study the effects of mechanical, thermal and moisture loading and combinations thereof on computed joint stresses

  18. A Multi-Objective Advanced Design Methodology of Composite Beam-to-Column Joints Subjected to Seismic and Fire Loads

    SciTech Connect

    Pucinotti, Raffaele [Department of Mechanics and Materials, Mediterranean University of Reggio Calabria, loc. Feo di Vito, Reggio Calabria, 89126 (Italy); Ferrario, Fabio; Bursi, Oreste S. [Department of Mechanical and Structural Engineering, University of Trento, via Mesiano 7, Trento, 38050 (Italy)

    2008-07-08

    A multi-objective advanced design methodology dealing with seismic actions followed by fire on steel-concrete composite full strength joints with concrete filled tubes is proposed in this paper. The specimens were designed in detail in order to exhibit a suitable fire behaviour after a severe earthquake. The major aspects of the cyclic behaviour of composite joints are presented and commented upon. The data obtained from monotonic and cyclic experimental tests have been used to calibrate a model of the joint in order to perform seismic simulations on several moment resisting frames. A hysteretic law was used to take into account the seismic degradation of the joints. Finally, fire tests were conducted with the objective to evaluate fire resistance of the connection already damaged by an earthquake. The experimental activity together with FE simulation demonstrated the adequacy of the advanced design methodology.

  19. Analysis of the stress-strain state in single overlap joints using piezo-ceramic actuators

    NASA Astrophysics Data System (ADS)

    P?ltânea, Veronica; P?ltânea, Gheorghe; Popovici, Dorina; Jiga, Gabriel; Papanicolaou, George

    2014-05-01

    In this paper is presented a 2D approach to finite element modeling and an analytical calculus of a single lap bonded joint. As adherent material were selected a sheet of wood, aluminum and titanium. For adhesive part were selected Bison Super Wood D3 in case of the wood single lap joint and an epoxy resin type DGEBA-TETA for gluing together aluminum and titanium parts. In the article is described a combined method, which consists in the placement of the piezoelectric actuator inside of the adhesive part, in order to determine the tensile stress in the overlap joint. A comparison between the analytical and numerical results has been achieved through a multiphysics modeling - electrical and mechanical coupled problem. The technique used to calculate the mechanical parameters (First Principal Stress, displacements) was the three-point bending test, where different forces were applied in the mid-span of the structure, in order to maintain a constant displacement rate. The length of the overlap joint was modified from 20 to 50 mm.

  20. Friction of composite cushion bearings for total knee joint replacements under adverse lubrication conditions.

    PubMed

    Stewart, T; Jin, Z M; Fisher, J

    1997-01-01

    Conventional joint replacements consist of a polished metallic or ceramic component articulating against a layer of polyethylene. Although the friction in the contact between these articulating surfaces is low, polyethylene wear is produced as a result of a boundary/mixed lubrication regime. Wear debris is generated by direct asperity contact, abrasion, adhesion and fatigue, and has been shown to cause adverse tissue reactions which can lead to joint failure. The introduction of soft compliant materials, similar in stiffness to articular cartilage, has shown that with cyclic loading and relative motion between the articulating surfaces typical of normal walking, a fluid film can be maintained through combined entraining and squeeze-film actions, and hence wear can be minimized. For 95 per cent of the time, however, we are not walking but standing still or moving slowly. A pendulum simulator has been used in the present study to investigate the effect of adverse tribological conditions which may lead to fluid film breakdown, such as severe cyclic loading, particularly in the swing phase, reduced sliding velocity, reduced stroke length and start-up after a period of constant loading. Friction of a model composite cushion knee bearing, manufactured from a graded modulus (20-1000 MPa) layer of polyurethane, sliding against a polished metal cylinder has been measured for various lubricants and the results have been analysed using a Stribeck assessment. Severe cyclic loading, decreased sliding velocity and decreased stroke length have been found to limit the degree of fluid entrainment previously allowed during the swing phase of normal walking, thus allowing breakdown of fluid films and elevated levels of friction and surface damage. Soft layer joint replacements must therefore be designed to operate with thick elastohydrodynamic fluid films to provide some degree of protection when tribological conditions become severe, or alternatively incorporate alternative boundary or mixed lubrication mechanisms. This study quantifies a potential limitation of the cushion bearing concept. PMID:9509883

  1. Methodology for optimal configuration in structural health monitoring of composite bonded joints

    NASA Astrophysics Data System (ADS)

    Quaegebeur, N.; Micheau, P.; Masson, P.; Castaings, M.

    2012-10-01

    In this study, a structural health monitoring (SHM) strategy is proposed in order to detect disbonds in a composite lap-joint. The structure under study is composed of a carbon fiber reinforced polymer (CFRP) bonded to a titanium plate and artificial disbonds are simulated by inserting Teflon tapes of various dimensions within the joint. In situ inspection is ensured by piezoceramics bonded to the structure to generate and measure guided waves. Theoretical propagation and through-thickness stress distribution are first studied in order to determine damage sensitivity with respect to the mode and frequency of the generated guided wave. The optimal configuration of the system in terms of piezoceramic size, shape and inter-unit spacing is then validated using finite element modeling (FEM) in 3D. Experimental assessment of propagation characteristics is conducted using laser Doppler vibrometer (LDV) in order to justify theoretical and numerical assumptions and pitch-catch measurements are then performed to validate the efficient detection of the damage and accurate estimation of its size.

  2. Structural tests and development of a laminar flow control wing surface composite chordwise joint

    NASA Technical Reports Server (NTRS)

    Lineberger, L. B.

    1984-01-01

    The dramatic increases in fuel costs and the potential for periods of limited fuel availability provided the impetus to explore technologies to reduce transport aircraft fuel consumption. NASA sponsored the Aircraft Energy Efficiency (ACEE) program beginning in 1976 to develop technologies to improve fuel efficiency. The Lockheed-Georgia Company accomplished under NAS1-16235 Laminar-Flow-Control (LFC) Wing Panel Structural Design and Development (WSSD); design, manufacturing, and testing activities. An in-depth preliminary design of the baseline 1993 LFC wing was accomplished. A surface panel using the Lockheed graphite/epoxy integrated LFC wing box structural concept was designed. The concept was shown by analysis to be structurally efficient and cost effective. Critical details of the surface and surface joint was demonstrated by fabricating and testing complex, concept selection specimens. The Lockheed-Georgia Company accomplishments, Development of LFC Wind Surface Composite Structures (WSCS), are documented. Tests were conducted on two CV2 panels to verify the static tension and fatigue strength of LFC wing surface chordwise joints.

  3. Simplified linear and non-linear analysis of stepped and scarfed adhesive-bonded lap-joints between composite laminates

    Microsoft Academic Search

    Flemming Mortensen; Ole Thybo Thomsen

    1997-01-01

    This paper presents a newly developed unified approach for the analysis and design of adhesive-bonded stepped and scarfed lap-joints. The adherends are modelled as beams or wide plates in cylindrical bending, and are considered as generally orthotropic laminates using classical laminate theory. Consequently, adherends made as asymmetric and unbalanced composite laminates can be included in the analysis. The adhesive layer

  4. Flaw Tolerance in Lap Shear Brazed Joints. Part 1

    NASA Technical Reports Server (NTRS)

    Flom, Yury; Wang, Liqin; Obenschain, Arthur F. (Technical Monitor)

    2002-01-01

    Vacuum brazing is a viable process to achieve strong permanent and hermetic joints in space. As in any joining process, brazed Joints have various imperfections and defects. It is important to understand the impact that flaws have on the load carrying capacity and performance of the brazed joints. This study focuses on the behavior of lap shear joints due to their engineering importance in brazed aerospace structures. In Part 1 an average shear strength capabilitY and failure modes of the single lap joints are explored. Specimens comprised of 0.090 inch thick 347 stainless steel sheet brazed with pure silver are tested in accordance with the AWS C3.2 standard. Comparison of the measured loads and average shear stresses at failure with the Finite Element Analysis (FEA) of the same specimens as a function of the overlap lengths shows excellent correlation between the experimental and calculated values for the defect-free lap joints. In Part 2, various flaws will be introduced in the test specimens to simulate lack of braze coverage in the lap joints. Mechanical testing and FEA will be performed on these joints to verify if behavior of ductile ]appoints containing flaws is similar to the joints with the reduced braze area. Finally, in Part 3, the results obtained in Part 1 and 2 will be applied to the brazed assembly to evaluate a load carrying capability of the structural lap joint containing defects.

  5. Joint Strength Control at the Fiber/Matrix Interface during the Production of Polymer Composite Materials Reinforced with High Performance Fibers

    NASA Astrophysics Data System (ADS)

    Kudinov, Vladimir V.; Korneeva, Natalia V.

    2010-06-01

    The paper presents the results obtained in the study of the joint strength between polymer matrix and high performance polyethylene fiber. The fiber/matrix joints simulate the unit cell of the fiber-reinforced composite materials. Effect of heat treatment on the composite properties at the interface was estimated by a multifilament wet-pull-out method. It was found that the joint strength may be increased with the help of extra heart treatment. Both the energy to peak load and the energy to failure for CM joints at various stages of loading were determined.

  6. Effect of filler metal composition on the strength of yttria stabilized zirconia joints brazed with Pd-Ag-CuOx

    SciTech Connect

    Darsell, Jens T.; Weil, K. Scott

    2008-09-08

    The Ag-CuOx system is of interest to be used to be used as an air braze filler metal for joining high temperature electrochemical devices. Previous work has shown that the melting temperatures can be increased by adding palladium to Ag-CuOx and it is expected that this may aid high temperature stability. This work compares the room temperature bend strength of joints made between yttria-stabilized zirconia (YSZ) air brazed using Ag-CuOx without palladium and with 5 and 15mol% palladium additions. It has been found that in general palladium decreases joint strength, especially in low copper oxide compositions filler metals. At high copper oxide contents, brittle fracture through both copper oxide rich phases and the YSZ limits joint strength.

  7. Microstructure and the elemental and phase compositions of the diffusion joint of grade 45 steel through a powder layer

    NASA Astrophysics Data System (ADS)

    Zeer, G. M.; Zelenkova, E. G.; Belousov, O. V.; Koroleva, Yu. P.; Fedorova, E. N.; Mikheev, A. A.

    2015-04-01

    The microstructures of the transition zone and the powder layer, the concentration distribution of chemical elements across a diffusion joint, and the microhardness of the grade 45 steel-Ni powder layer-grade 45 steel layered composite materials fabricated by diffusion welding at various temperatures are studied. It is shown that the deposition of a nickel sublayer on steel and the application of a submicron nickel powder as an activating layer make it possible to form a high-quality diffusion joint at a temperature of 850°C, which is ~0.6 of the melting temperature of nickel (which has the lowest melting temperature in the given composite material). The sintering of a nickel powder and the formation of a transition zone between the nickel layer and steel occur simultaneously in a solid phase during diffusion joining. The transition zone consists of an ?-Fe solid solution and the FeNi3 compound.

  8. Strength and Mechanics of Bonded Scarf Joints for Repair of Composite Materials

    NASA Technical Reports Server (NTRS)

    Pipes, R. B.; Adkins, D. W.

    1982-01-01

    Experimental and analytical investigations of scarf joints indicate that slight bluntness of adherend tips induces adhesive stress concentrations which significantly reduce joint strength, and the stress distribution through the adhesive thickness is non-uniform and has significant stress concentrations at the ends of the joint. The laminate stacking sequence can have important effects on the adhesive stress distribution. A significant improvement in joint strength is possible by increasing overlap at the expense of raising the repair slightly above the original surface. Although a surface grinder was used to make most experimental specimens, a hand held rotary bur can make a surprisingly good scarf. Scarf joints wit doublers on one side, such as might be used for repair, bend under tensile loads and may actually be weaker than joints without doublers.

  9. Analysis of a Preloaded Bolted Joint in a Ceramic Composite Combustor

    NASA Technical Reports Server (NTRS)

    Hissam, D. Andy; Bower, Mark V.

    2003-01-01

    This paper presents the detailed analysis of a preloaded bolted joint incorporating ceramic materials. The objective of this analysis is to determine the suitability of a joint design for a ceramic combustor. The analysis addresses critical factors in bolted joint design including preload, preload uncertainty, and load factor. The relationship between key joint variables is also investigated. The analysis is based on four key design criteria, each addressing an anticipated failure mode. The criteria are defined in terms of margin of safety, which must be greater than zero for the design criteria to be satisfied. Since the proposed joint has positive margins of safety, the design criteria are satisfied. Therefore, the joint design is acceptable.

  10. Modelling the joint variability of grain size and chemical composition in sediments

    NASA Astrophysics Data System (ADS)

    Bloemsma, M. R.; Zabel, M.; Stuut, J. B. W.; Tjallingii, R.; Collins, J. A.; Weltje, G. J.

    2012-12-01

    The geochemical composition of siliciclastic sediments correlates strongly with grain size. Hence, geochemical composition may serve as a grain-size proxy. In the absence of grain-size variations, geochemical data of siliciclastic sediments may be used to characterise size-independent processes, i.e., sediment provenance, weathering, mixing, shape/density sorting and diagenesis. In general, however, geochemical data sets contain both types of information. In order to formalise interpretation of geochemical data, we propose a mathematical method to decompose the total geochemical variability of a series of genetically related specimens into a grain-size dependent (the shared signal) and a grain-size independent part (the residual signal). The former may serve as a proxy for grain size whereas the latter represents geochemical variability that would have been observed if all sediments would have had the same grain-size distribution. The two data sets are jointly decomposed by means of Partial Least Squares (PLS) and orthogonal projection. Subsequently, the presence of significant grain-size independent geochemical variability in the residual signal is determined in a statistically rigorous manner using a ?2-test. Using a synthetic example, we show that the residual record effectively reveals an imposed provenance signal which could not have been resolved from the geochemical or grain-size data sets individually. We analysed the relation between grain size and geochemical composition in three Quaternary marine sediment cores located offshore West Africa and South America (GeoB7920-2, GeoB9508-5 and GeoB7139-2). Both sites are characterised by biogenic sediment input, in addition to fluvial and aeolian sediment input from the continent. It was found that all cores show a strong, but different correlation between the mean grain size and the bulk geochemical composition. These results demonstrate that geochemical grain-size proxies are empirical and site-specific. It was also found that the geochemical and grain-size data in cores GeoB7920-2 and GeoB7139-2 do not contain unique information, whereas in core GeoB9508-5 Ti varies independently from the grain size. This residual Ti-signal correlates with the transport mechanism, as demonstrated by statistically different values of aeolian and fluvial-dominated sediments. However, a unique interpretation of this residual signal in terms of the postulated grain-size independent mechanisms could not be provided without additional information. We conclude that the proposed model facilitates identification and validation of different element ratios as grain-size proxies and, more importantly, as proxies for size-independent processes. For this reason, the model paves the way for rigorous analysis of multi-proxy data, which are widely used in palaeoceanographic and palaeoclimatic research.

  11. Effects of load proportioning on the capacity of multiple-hole composite joints

    NASA Technical Reports Server (NTRS)

    Hyer, M. W.; Chastain, P. A.

    1985-01-01

    This study addresses the issue of adjusting the proportion of load transmitted by each hole in a multiple-hole joint so that the joint capacity is a maximum. Specifically two-hole-in-series joints are examined. The results indicate that when each hole reacts 50% of the total load, the joint capacity is not a maximum. One hole generally is understressed at joint failure. The algorithm developed to determine the load proportion at each hole which results in maximum capacity is discussed. The algorithm includes two-dimensional finite-element stress analysis and failure criteria. The algorithm is used to study the effects of joint width, hole spacing, and hole to joint-end distance on load proportioning and capacity. To study hole size effects, two hole diameters are considered. Three laminates are considered: a quasi-isotropic laminate; a cross-ply laminate; and a 45 degree angle-ply laminate. By proportioning the load, capacity can be increased generally from 5 to 10%. In some cases a greater increase is possible.

  12. Stresses in adhesively bonded joints - A closed-form solution

    NASA Technical Reports Server (NTRS)

    Delale, F.; Erdogan, F.; Aydinoglu, M. N.

    1981-01-01

    The general plane strain problem of adhesively bonded structures consisting of two different, orthotropic adherends is considered, under the assumption that adherend thicknesses are constant and small in relation to the lateral dimensions of the bonded region, so that they may be treated as plates. The problem is reduced to a system of differential equations for the adhesive stresses which is solved in closed form, with a single lap joint and a stiffened plate under various loading conditions being considered as examples. It is found that the plate theory used in the analysis not only predicts the correct trend for adhesive stresses but gives surprisingly accurate results, the solution being obtained by assuming linear stress-strain relations for the adhesive.

  13. Effect of the axial stress and the magnetic field on the critical current and the electric resistance of the joints between HTS coated conductors

    NASA Astrophysics Data System (ADS)

    Konstantopoulou, K.; Sarazin, M.; Granados, X.; Y Pastor, J.; Obradors, X.

    2015-06-01

    High temperature superconducting (HTS) wires require a detailed characterization of the possible degradation of their properties by handling at room temperature as well as during their service life, establishing the limits for associated functional devices and systems. In this paper, we study the mechanical behavior of spliced joints between commercial HTS coated conductors based on YBCO at room (300 K) and service temperatures (77 K). Single lap shear tests were performed and the evolution of the critical current and electric resistivity of the joints were measured. The complete strain field for the tape and joints was also obtained by digital image correlation. In addition, tensile tests under an external magnetic field were performed, and the effect of the applied field on the critical current and electric resistivity of the joints were studied. Finally, finite element simulations were employed to reproduce the distribution of the stress field developed in the spliced joint samples during axial loading.

  14. Active Metal Brazing and Characterization of Brazed Joints in C-C and C-SiC Composites to Copper-Clad-Molybdenum System

    NASA Technical Reports Server (NTRS)

    Singh, M.; Asthana, R.

    2008-01-01

    Carbon/carbon composites with CVI and resin-derived matrices, and C/SiC composites reinforced with T-300 carbon fibers in a CVI SiC matrix were joined to Cu-clad Mo using two Ag-Cu braze alloys, Cusil-ABA (1.75% Ti) and Ticusil (4.5% Ti). The brazed joints revealed good interfacial bonding, preferential precipitation of Ti at the composite/braze interface, and a tendency toward delamination in resin-derived C/C composite. Extensive braze penetration of the inter-fiber channels in the CVI C/C composites was observed. The Knoop microhardness (HK) distribution across the C/C joints indicated sharp gradients at the interface, and a higher hardness in Ticusil than in Cusil-ABA. For the C/SiC composite to Cu-clad-Mo joints, the effect of composite surface preparation revealed that ground samples did not crack whereas unground samples cracked. Calculated strain energy in brazed joints in both systems is comparable to the strain energy in a number of other ceramic/metal systems. Theoretical predictions of the effective thermal resistance suggest that such joined systems may be promising for thermal management applications.

  15. Evaluation of Bolt Bearing Behavior of Highly Loaded Composite Joints at Elevated Temperature

    Microsoft Academic Search

    Hafiz Ahmad; W. S. Johnson; W. A. Counts

    2003-01-01

    The high load intensities and elevated temperature in the wing and fuselage of a supersonic transport aircraft will result in bolted joints stack-up thickness much greater than the current subsonic transport aircraft. Bolt bearing– bypass tests were conducted to develop a database and a bearing–bypass stress interaction for the design community. All test coupons are IM7\\/PETI-5 quasi-isotropic laminates (64 plies)

  16. Design, fabrication and test of graphite/polyimide composite joints and attachments for advanced aerospace vehicles

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Principal program activities dealt with the literature survey, design of joint concepts, assessment of GR/PI material quality, fabrication of test panels and specimens, and small specimen testing. Bonded and bolted designs are presented for each of the four major attachment types. Quality control data are presented for prepreg Lots 2W4651 and 3W2020. Preliminary design allowables test results for tension tests and compression tests of laminates are also presented.

  17. Surface modifications of nylon/carbon fiber composite for improving joint adhesion

    SciTech Connect

    Wu, R.; Liao, S.L.; Tong, T.S.; Young, J.T. [UCL, ITRI, Hsinchu (Taiwan, Province of China)

    1996-12-31

    Various methods were used to modify the nylon/carbon fiber composite surfaces, including grit blasting, flame and plasma pretreatments. The surfaces of nylon composites after pretreatments were characterized by contact angle measurements, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). XPS results show that several functional groups were formed after plasma and flame pretreatments. The scanning electron microscope (SEM) photographs suggest that the blasting pretreatment increased the surface roughness of nylon composites. All these surface pretreatments dramatically increased the lap shear strength if proper operation conditions were used. The reasons for the increase of lap shear strength were explained.

  18. High conductivity composite flip-chip joints and silver-indium bonding to bismuth telluride for high temperature applications

    NASA Astrophysics Data System (ADS)

    Lin, Wen P.

    Two projects are reported. First, the barrier layer and silver (Ag)-indium (In) transient liquid phase (TLP) bonding for thermoelectric (TE) modules at high temperature were studied, and followed with a survey of Ag microstructure and grain growth kinetics. Second, the high electrical conductivity joint materials bonded by both Ag-AgIn TLP and solid-state bonding processes for small size flip-chip applications were designed. In the first project, barrier and Ag-In TLP bonding layer for TE module at high temperature application were studied. Bismuth telluride (Bi2 Te3) and its alloys are used as materials for a TE module. A barrier/bonding composite was developed to satisfy the TE module for high temperature operation. Titanium (Ti)/ gold (Au) was chosen as the barrier layers and an Ag-rich Ag-In joint was chosen as the bonding layer. An electron-beam evaporated Ti layer was selected as the barrier layer. An Ag-In fluxless TLP bonding process was developed to bond the Bi 2Te3 chips to the alumina substrates for high temperature applications. To prepare for bonding, the Bi2Te3 chips were coated with a Ti/Au barrier layer followed by a Ag layer. The alumina substrates with titanium-tungsten (TiW)/Au were then electroplated with the Ag/In/Ag structure. These Bi2Te3 chips were bonded to alumina substrates at a bonding temperature of 180ºC with a static pressure as low as 100psi. The resulting void-free joint consists of five regions: Ag, (Ag), Ag2In, (Ag), and Ag, where (Ag) is Ag-rich solid solution with In atoms in it and Ag is pure Ag. This joint has a melting temperature higher than 660ºC, and it manages the coefficient of thermal expansion (CTE) mismatch between the Bi2Te3 and alumina substrate. The whole Ti/Au barrier layer and Ag-In bonding composite between Bi 2Te3 and alumina survived after an aging test at 250°C for 200 hours. The Ag-In joint transformed from Ag/(Ag)/Ag2In/(Ag)/Ag to a more reliable (Ag) rich layer after the aging test. Ag thin films were grown on various substrates and annealed at different conditions. The substrates include alumina metalized with TiW/Au, Bi 2Te3 metalized with palladium (Pd)/Au, silicon (Si) metalized with chromium (Cr)/Au, Si metalized with Pd/Au, 304 stainless steel metalized with nickel (Ni), and copper (Cu). The pre-exponential factor and activation energy of Ag grown on alumina/TiW/Au and Si/Cr/Au at 250-450°C were deduced from experimental results as 1.26cm2/s and 153kJ/mol, and as 0.07cm2/s and 140kJ/mol, respectively. In the second project, we studied the Ag-AgIn bonding and solid-state bonding. Several joint materials and bonding systems were studied with small dimenstion (10?m and 40mum) flip-chip designs, which include Ag joint with Ag-In transient liquid phase bonding, and Ag, Ag/Au and Cu/Au interconnections with solid-state bonding. The 40?m Ag-AgIn flip-chip interconnect process occurs at 180°C. An array of 50x50 Ag flip-chip joints with a 100?m pitch and 40?m joint diameter was created and bonded to the Cu substrate by depositing Ag/In/Ag at 180°C. The joint has a structure of Ag/(Ag)/Ag2In/(Ag) that connects the Si chip to the Cu substrate. The whole joint layer has a minimum melting temperature at 660°C. Cu/Au, Ag/Au, and Ag flip-chip interconnects were bonded to Cu substrate by solid-state bonding. The Cu substrate here was emulated as Cu electrodes on a package substrate. During the solid-state bonding process, heat and pressure were applied, and the bonding was done in a 100 torr vacuum. In the Cu/Au and Ag/Au flip-chip solid-state bonding experiments, an array of Cu/Au or Ag/Au interconnects with columns of 40mum x 40mum were created by photolithography and electroplating processes, and then bonded to the Cu substrate using a solid-state bonding process at 200°C with a static pressure of 250-400psi. The corresponding load for each column was set to as low as 0.22-0.35g. Cross section SEM images show that Cu/Au columns were all well bonded to the Cu substrate without any voids or cracks. The measured fracture force of Cu/Au and Ag/Au flip-chips wer

  19. A Study of Hybrid Insulation Composition Joint using Gas and Solid Insulator for Gas Insulated Power Equipment

    NASA Astrophysics Data System (ADS)

    Shinkai, Hiroyuki; Goshima, Hisashi; Yashima, Masafumi

    SF6 is used as the main insulation gas for gas-insulated switchgear (GIS), but it has recently become a gas that must be restricted because of its greenhouse effect. To date, we have studied the insulation characteristics of compressed N2 and CO2 as a possible alternative for SF6. We have reported that N2 or CO2 must be pressurized up to 2.0MPa when it is used as a substitute for SF6 of 0.5MPa. Therefore, we have proposed a hybrid insulation composition that uses the gas and solid insulators. Because the central conductor of GIS is the covered by solid insulator in this composition, the high-pressure gas of 2.0MPa is not needed. However, the joint of the solid insulator becomes the weak point for discharge development. In this paper, we describe the effective configuration for the improvement of withstand voltage on the basis of the experiment. As a result, the most effective connector was made of resin without an implanted electrode and the configuration was the case without the solid-solid interface between the solid insulator of the central conductor and the resin connector. In this experiment, the improvement of the breakdown electric field of the hybrid composition was 44% or more compared with the case of only gas insulation (conventional method). In addition, a further improvement can be expected by optimizing the insulation creepage distance and configuration.

  20. Evolution equations for the joint probability of several compositions in turbulent combustion

    SciTech Connect

    Bakosi, Jozsef [Los Alamos National Laboratory

    2010-01-01

    One-point statistical simulations of turbulent combustion require models to represent the molecular mixing of species mass fractions, which then determine the reaction rates. For multi-species mixing the Dirichlet distribution has been used to characterize the assumed joint probability density function (PDF) of several scalars, parametrized by solving modeled evolution equations for their means and the sum of their variances. The PDF is then used to represent the mixing state and to obtain the chemical reactions source terms in moment closures or large eddy simulation. We extend the Dirichlet PDF approach to transported PDF methods by developing its governing stochastic differential equation (SDE). The transport equation, as opposed to parametrizing the assumed PDF, enables (1) the direct numerical computation of the joint PDF (and therefore the mixing model to directly account for the flow dynamics (e.g. reaction) on the shape of the evolving PDF), and (2) the individual specification of the mixing timescales of each species. From the SDE, systems of equations are derived that govern the first two moments, based on which constraints are established that provide consistency conditions for material mixing. A SDE whose solution is the generalized Dirichlet PDF is also developed and some of its properties from the viewpoint of material mixing are investigated. The generalized Dirichlet distribution has the following advantages over the standard Dirichlet distribution due to its more general covariance structure: (1) its ability to represent differential diffusion (i.e. skewness) without affecting the scalar means, and (2) it can represent both negatively and positively correlated scalars. The resulting development is a useful representation of the joint PDF of inert or reactive scalars in turbulent flows: (1) In moment closures, the mixing physics can be consistently represented by one underlying modeling principle, the Dirichlet or the generalized Dirichlet PDF, and (2) based on the SDEs transported PDF mixing models for multi-species diffusion can be constructed by specifying the SDE coefficients.

  1. Extracellular matrix stiffness and composition jointly regulate the induction of malignant phenotypes in mammary epithelium

    NASA Astrophysics Data System (ADS)

    Chaudhuri, Ovijit; Koshy, Sandeep T.; Branco da Cunha, Cristiana; Shin, Jae-Won; Verbeke, Catia S.; Allison, Kimberly H.; Mooney, David J.

    2014-10-01

    In vitro models of normal mammary epithelium have correlated increased extracellular matrix (ECM) stiffness with malignant phenotypes. However, the role of increased stiffness in this transformation remains unclear because of difficulties in controlling ECM stiffness, composition and architecture independently. Here we demonstrate that interpenetrating networks of reconstituted basement membrane matrix and alginate can be used to modulate ECM stiffness independently of composition and architecture. We find that, in normal mammary epithelial cells, increasing ECM stiffness alone induces malignant phenotypes but that the effect is completely abrogated when accompanied by an increase in basement-membrane ligands. We also find that the combination of stiffness and composition is sensed through ?4 integrin, Rac1, and the PI3K pathway, and suggest a mechanism in which an increase in ECM stiffness, without an increase in basement membrane ligands, prevents normal ?6?4 integrin clustering into hemidesmosomes.

  2. Modeling of fracture and durability of paste-bonded composite joints subjected to hygro-thermal-mechanical loading

    NASA Astrophysics Data System (ADS)

    Harris, David Lee

    The objective of the research is to characterize the behavior of composite/composite joints with paste adhesive using both experimental testing and analytical modeling. In comparison with the conventional tape adhesive, joining composites using paste adhesive provides several advantages. The carbon fiber laminate material systems employed in this study included IM7 carbon fibers and 977-3 epoxy matrix assembled in prepreg tape, and AS4 carbon fibers and 977-3 epoxy matrix as a five-harness satin weave. The adhesive employed was EA 9394 epoxy. All laminates and test specimens were fabricated and inspected by Boeing using their standard propriety procedures. Three types of test specimens were used in the program. They were bonded double-lap shear (DLS), bonded double cantilever beam (DCB) and bonded interlaminar tension (ILT) specimens. A group of specimens were conditioned at elevated temperature and humidity in an environmental chamber at Boeing's facility and their moisture absorption recorded with time. Specimens were tested at room temperature dry and elevated temperatures. DCB and DLS specimens were tested in fatigue as well as static conditions. Two-dimensional finite element models of the three configurations were developed for determining stresses and strains using the ABAQUS finite element package code. Due to symmetry, only the one-half of the specimen needed to be considered thus reducing computational time. The effect of the test fixture is not taken into account instead equivalent distributed stresses are applied directly on the composite laminates. For each of the specimen, the distribution of Mises stress and the first strain invariant J1 are obtained to identify potential failure locations within a specimen.

  3. Metabolism and composition of the canine anterior cruciate ligament relate to differences in knee joint mechanics and predisposition to ligament rupture

    Microsoft Academic Search

    Eithne J. Comerford; John F. Tarlton; John F. Innes; Kenneth A. Johnson; Andrew A. Amis; Allen J. Bailey

    2005-01-01

    Purpose: The objective of this study was to determine whether differences in the composition and metabolism of the extracellular matrix (ECM) in canine anterior cruciate ligaments (ACLs) might relate to mechanical properties of the canine knee. Variations in ACL biochemistry and knee mechanics could account for divergent predispositions to ligament rupture.Methods: Eleven knee joints were obtained from both cadaveric Labrador

  4. Measurement of adhesive joint fracture properties as a function of environmental degradation

    SciTech Connect

    Wylde, J.W.; Spelt, J.K. [Univ. of Toronto, Ontario (Canada)

    1996-12-31

    The increased use of structural adhesives in industry would benefit from a comprehensive failure load prediction tool to ensure competent design. The work of Fernlund and Spelt has proposed a fracture envelope that relates the critical strain energy release rate to the nominal phase angle of loading. The work of Plasinus and Spelt extended this work to incorporate the viscoelastic effect of the adhesive. The objective of the present research is to incorporate the effects of temperature and water absorption into the prediction of adhesive joint fracture. Ample evidence exists to demonstrate the notion that absorbed water has an effect predominantly detrimental, on the strength of an adhesive joint. Past work was concentrated on degrading typical, in service joints such as the Single Lap Shear (SLS) joint or the Cracked Lap Shear (CLS) joint. Since water is absorbed through the exposed edges, typically small in area compared to the volume of the joint, degradation times are usually long and the water concentration varies both with time and spatially throughout the joint. In this research, a novel method of degrading adhesive fracture specimens to a spatially constant degradation condition is being used to incorporate environmental effects into the fracture load prediction tool of Spelt et al.

  5. Effect of radial clearance between bolt and washer on the bearing strength of composite bolted joints

    SciTech Connect

    Herrington, P.D.; Sabbaghian, M. (Louisiana State University, Baton Rouge (United States))

    1992-01-01

    When composite materials are bolted together, the relative diameters of the bolt hole, the constraining washer and the bolt itself have a profound effect on the ultimate bearing strength. Previous studies have investigated the effects of clearance between the bolt and the hole diameter. In this study, the effect of the difference between the bolt diameter and the inside diameter of the washer, which provides the lateral constraint at the edge of the hole, is examined. To explain the significant variation of bearing strength with bolt-to-washer clearance, a model is proposed to explain the mechanics of load transfer and the lateral deformation at the edge of the hole. The test results, using a quasi-isotropic graphite epoxy laminate, support the proposed model and provide data for designers. 16 refs.

  6. A novel approach to predict the pin load distribution of multiple bolt-jointed composite laminate based on the circuit model

    NASA Astrophysics Data System (ADS)

    Yang, Xiankun; Chen, Haoyuan; Cheng, Linan; Zheng, Xitao

    2011-11-01

    The circuit model was applied to predict the pin load distribution of composite multiple bolt-joint structure. The load, flexibility and deformation of the mechanics model were equivalent to the current, resistance and voltage of the circuit model, respectively. Based on the above assumption, it could be found that the Hooke's law and the deformation compatibility equation in the origin mechanics model transformed into the Ohm's law and the voltage balance equation in the new circuit model. This approach translated the complex model of composite multiple bolt-jointed into a simple circuit model which consisted of some series circuits and parallel circuits. The analysis of the new circuit model had formed n-1 independence voltage balance equations and a current balance equation, thus, the current and load of each bolt could be calculated. In the new model, power sources which were added as required in some branch circuits could also simulate the clearance or interference in the origin model. Compared with the result of the multiple bolt-joints composite laminate test, the new approach could make an excellent performance to estimate the load distribution.

  7. A novel approach to predict the pin load distribution of multiple bolt-jointed composite laminate based on the circuit model

    NASA Astrophysics Data System (ADS)

    Yang, Xiankun; Chen, Haoyuan; Cheng, Linan; Zheng, Xitao

    2012-04-01

    The circuit model was applied to predict the pin load distribution of composite multiple bolt-joint structure. The load, flexibility and deformation of the mechanics model were equivalent to the current, resistance and voltage of the circuit model, respectively. Based on the above assumption, it could be found that the Hooke's law and the deformation compatibility equation in the origin mechanics model transformed into the Ohm's law and the voltage balance equation in the new circuit model. This approach translated the complex model of composite multiple bolt-jointed into a simple circuit model which consisted of some series circuits and parallel circuits. The analysis of the new circuit model had formed n-1 independence voltage balance equations and a current balance equation, thus, the current and load of each bolt could be calculated. In the new model, power sources which were added as required in some branch circuits could also simulate the clearance or interference in the origin model. Compared with the result of the multiple bolt-joints composite laminate test, the new approach could make an excellent performance to estimate the load distribution.

  8. Effect of current crowding and Joule heating on electromigration-induced failure in flip chip composite solder joints tested at room temperature

    NASA Astrophysics Data System (ADS)

    Nah, J. W.; Suh, J. O.; Tu, K. N.

    2005-07-01

    The electromigration of flip chip solder joints consisting of 97Pb-3Sn and 37Pb-63Sn composite solders was studied under high current densities at room temperature. The mean time to failure and failure modes were found to be strongly dependent on the change in current density. The composite solder joints did not fail after 1month stressed at 4.07×104A/cm2, but failed after just 10h of current stressing at 4.58×104A/cm2. At a slightly higher current stressing of 5.00×104A/cm2, the composite solder joints failed after only 0.6h due to melting. Precipitation and growth of Cu6Sn5 at the cathode caused the Cu under bump metallurgy to be quickly consumed and resulted in void formation at the contact area. The void reduced the contact area and displaced the electrical path, affecting the current crowding and Joule heating inside the solder bump. Significant Joule heating inside solder bumps can cause melting of the solder and quick failure. The effect of void propagation on current crowding and Joule heating was confirmed by simulation.

  9. Joint swelling

    MedlinePLUS

    Swelling of a joint ... Joint swelling may occur along with joint pain . The swelling may cause the joint to appear larger or abnormally shaped. Joint swelling can cause pain or stiffness. After an ...

  10. Adhesively-bonded joints and repairs in metallic alloys, polymers and composite materials: Adhesives, adhesion theories and surface pretreatment

    Microsoft Academic Search

    A. Baldan

    2004-01-01

    In the present paper, the following topics are reviewed in detail: (a) the available adhesives, as well as their recent advances, (b) thermodynamic factors affecting the surface pretreatments including adhesion theories, wettability, surface energy, (c) bonding mechanisms in the adhesive joints, (d) surface pretreatment methods for the adhesively bonded joints, and as well as their recent advances, and (e) combined

  11. The composition of coding joints formed in V(D)J recombination is strongly affected by the nucleotide sequence of the coding ends and their relationship to the recombination signal sequences.

    PubMed Central

    Ezekiel, U R; Sun, T; Bozek, G; Storb, U

    1997-01-01

    V(D)J recombination proceeds in two stages. Precise cleavage at the border of the conserved recombination signal sequences (RSSs) and the coding ends results in flush double-stranded signal ends and coding ends terminating in hairpins. In the second stage, the signal and coding ends are processed into signal and coding joints. Coding ends containing certain nucleotide homopolymers affect the efficiency of V(D)J recombination. In this study, we have tested the effect of small changes in coding-end nucleotide composition on the frequency of coding- and signal joint formation. Furthermore, we have determined the sequences of coding joints resulting from recombination of coding ends with different compositions. We found that the presence of two T nucleotides 5' of both RSSs, but not a single T, reduces the frequency of signal joint formation, i.e., interferes with the cleavage stage of V(D)J recombination. However, coding-joint processing is sensitive even to a single T. Both the sequence of the coding ends and the particular RSS (12-mer or 23-mer) with which the coding end is associated affect the final composition of the coding joints. Thus, the presence of P nucleotides, the conservation of one undeleted coding end, the formation of joints without any deletions, and the template-dependent insertion of nucleotides are strongly influenced by the coding-end nucleotide composition and/or RSS association. The implications of these results with respect to the processing of coding ends are discussed. PMID:9199354

  12. Microstructure and Shear Strength in Brazing Joint of Mo-Cu Composite with 304 Stainless Steel by Ni-Cr-P Filler Metal

    NASA Astrophysics Data System (ADS)

    Wang, Juan; Wang, Jiteng; Li, Yajiang; Zheng, Deshuang

    2015-07-01

    The brazing of Mo-Cu composite and 304 stainless steel was carried out in vacuum with Ni-Cr-P filler metal at 980 °C for 20 min. Microstructure in Mo-Cu/304 stainless steel joint was investigated by field-emission scanning electron microscope (FE-SEM) with energy dispersive spectrometer (EDS) and shear strength was measured by shearing test. The results indicate that shear strength of the Mo-Cu/304 stainless steel joint is about 155 MPa. There forms eutectic structure of ?-Ni solid solution with Ni3P in the braze seam. Ni-Cu(Mo) and Ni-Fe solid solution are at the interface beside Mo-Cu composite and 304 stainless steel, respectively. Shear fracture exhibits mixed ductile-brittle fracture feature with trans-granular fracture, ductile dimples and tearing edges. Fracture originates from the interface between brazing seam and Mo-Cu composite and it propagates to the braze seam due to the formation of brittle Ni5P2 and Cr3P precipitation.

  13. Electro-optically responsive composites of gold nanospheres in 5CB liquid crystal under direct current and alternating current joint action

    NASA Astrophysics Data System (ADS)

    Hadjichristov, Georgi B.; Marinov, Yordan G.; Petrov, Alexander G.; Bruno, Emanuela; Marino, Lucia; Scaramuzza, Nicola

    2014-02-01

    Direct current (DC) electro-optical (EO) control of transmitted laser beam intensity based on EO controlled coherent light scattering and diffraction by stationary longitudinal texture pattern (LTP) is achieved in planar-oriented cells with a composite mixture of polymer-coated gold spherical nanoparticles (Au-NPs) with a mean diameter of about 12 nm and the room-temperature nematic pentylcyanobiphenyl (5CB). At relatively low DC voltage of about 5 V, the effective scattering/diffraction by Au-NPs/5CB composites leads to a spatial spreading of transmitted coherent light from a low-power continuous wave laser beam, resulting in a drastic reduction of its local intensity. The effect is polarization dependent and is strongest when the polarization of the input laser beam is along the LTP. The EO response of Au-NPs/5CB mixtures is studied under DC and alternating current (AC) joint action with the aim of the potential use of these composite materials as EO controlled diffusers. The specific V-shaped sharp dip in the DC voltage-dependent coherent light transmittance of Au-NPs/5CB planar films, as well as the possibility for erasing the scattering/diffractive LTP in the films by joint low AC voltage, can be useful for EO applications in the field of process control and for detection of weak dynamic electric fields.

  14. Hypermobile joints

    MedlinePLUS

    ... hypermobile joints have an increased risk for joint dislocation and other problems. Extra care may be needed ... the joint? Is there any history of joint dislocation, difficulty walking, or difficulty using the arms? Further ...

  15. Bonded composite to metal scarf joint performance in an aircraft landing gear drag strut. [for Boeing 747 aircraft

    NASA Technical Reports Server (NTRS)

    Howell, W. E.

    1974-01-01

    The structural performance of a boron-epoxy reinforced titanium drag strut, which contains a bonded scarf joint and was designed to the criteria of the Boeing 747 transport, was evaluated. An experimental and analytical investigation was conducted. The strut was exposed to two lifetimes of spectrum loading and was statically loaded to the tensile and compressive design ultimate loads. Throughout the test program no evidence of any damage in the drag strut was detected by strain gage measurements, ultrasonic inspection, or visual observation. An analytical study of the bonded joint was made using the NASA structural analysis computer program NASTRAN. A comparison of the strains predicted by the NASTRAN computer program with the experimentally determined values shows excellent agreement. The NASTRAN computer program is a viable tool for studying, in detail, the stresses and strains induced in a bonded joint.

  16. Structural FEM analysis of the strut-to-fuselage joint of a two-seat composite aircraft

    SciTech Connect

    Vargas-Rojas, Erik, E-mail: erikvargasrojas@hotmail.com; Camarena-Arellano, Diego, E-mail: erikvargasrojas@hotmail.com; Hernández-Moreno, Hilario, E-mail: erikvargasrojas@hotmail.com [IPN, ESIME Ticomán, Av. Ticomán 600, Col. San José Ticomán 07340 (Mexico)

    2014-05-15

    An analysis of a strut-to-fuselage joint is realized in order to evaluate the zones with a high probability of failure by means of a safety factor. The whole section is analyzed using the Finite Element Method (FEM) so as to estimate static resistance behavior, therefore it is necessary a numerical mock-up of the section, the mechanical properties of the Carbon-Epoxy (C-Ep) material, and to evaluate the applied loads. Results of the analysis show that the zones with higher probability of failure are found around the wing strut and the fuselage joint, with a safety factor lower than expected in comparison with the average safety factor used on aircrafts built mostly with metals.

  17. Seismic retrofitting of damaged exterior beam–column joints using fibre reinforced plastic composite–steel plate combined technique

    Microsoft Academic Search

    Saptarshi Sasmal; Balthasar Novák; K. Ramanjaneyulu; V. Srinivas; Constanze Roehm; N. Lakshmanan; Nagesh R. Iyer

    2010-01-01

    A conventional gravity load design philosophy for reinforced concrete (RC) structures has been slowly replaced by seismic design since the 1970s. But, till recently, capacity design and ductile detailing were not strictly implemented in practice in many developing countries which are prone to seismic hazard. In the present study, performance of exterior beam–column joints designed based on ductile and non-ductile

  18. The Effect of Composition on the Wetting Behavior and Joint Strength of the Ag-CuO Reactive Air Braze

    Microsoft Academic Search

    K. Scott Weil; Christopher A. Coyle; Jin Yong Y. Kim; John S. Hardy

    2003-01-01

    One of the challenges in manufacturing solid-state electrochemical devices is in joining the ceramic and metallic components such that the resulting joint is rugged, hermetic, and stable under continuous high temperature operation in an oxidizing atmosphere. A well proven method of joining dissimilar materials is by brazing. Unfortunately many of the commercially available ceramic-to-metal braze alloys exhibit oxidation behavior which

  19. Density, temperature, and composition of the North American lithosphere—New insights from a joint analysis of seismic, gravity, and mineral physics data: 2. Thermal and compositional model of the upper mantle

    NASA Astrophysics Data System (ADS)

    Tesauro, Magdala; Kaban, Mikhail K.; Mooney, Walter D.; Cloetingh, Sierd A. P. L.

    2014-12-01

    and compositional variations of the North American (NA) lithospheric mantle are estimated using a new inversion technique introduced in Part 1, which allows us to jointly interpret seismic tomography and gravity data, taking into account depletion of the lithospheric mantle beneath the cratonic regions. The technique is tested using two tomography models (NA07 and SL2013sv) and different lithospheric density models. The first density model (Model I) reproduces the typical compositionally stratified lithospheric mantle, which is consistent with xenolith samples from the central Slave craton, while the second one (Model II) is based on the direct inversion of the residual gravity and residual topography. The results obtained, both in terms of temperature and composition, are more strongly influenced by the input models derived from seismic tomography, rather than by the choice of lithospheric density Model I versus Model II. The final temperatures estimated in the Archean lithospheric root are up to 150°C higher than in the initial thermal models obtained using a laterally and vertically uniform "fertile" compositional model and are in agreement with temperatures derived from xenolith data. Therefore, the effect of the compositional variations cannot be neglected when temperatures of the cratonic lithospheric mantle are estimated. Strong negative compositional density anomalies (<-0.03 g/cm3), corresponding to Mg # (100 × Mg/(Mg + Fe)) >92, characterize the lithospheric mantle of the northwestern part of the Superior craton and the central part of the Slave and Churchill craton, according to both tomographic models. The largest discrepancies between the results based on different tomography models are observed in the Proterozoic regions, such as the Trans Hudson Orogen (THO), Rocky Mountains, and Colorado Plateau, which appear weakly depleted (>-0.025 g/cm3 corresponding to Mg # ˜91) when model NA07 is used, or locally characterized by high-density bodies when model SL2013sv is used. The former results are in agreement with those based on the interpretation of xenolith data. The high-density bodies might be interpreted as fragments of subducted slabs or of the advection of the lithospheric mantle induced from the eastward-directed flat slab subduction. The selection of a seismic tomography model plays a significant role when estimating lithospheric density, temperature, and compositional heterogeneity. The consideration of the results of more than one model gives a more complete picture of the possible compositional variations within the NA lithospheric mantle.

  20. Joint strength in RCS frames 

    E-print Network

    Kirby, Cynthia Dawn

    1998-01-01

    for the addition of a RC slab, cover plates, and band plates. Results indicated that the addition of a reinforced concrete slab compositely connected to the steel beams framing into a typical RCS joints as defined by the ASCE guidelines (1994), improved the joint...

  1. Evaluation of a high temperature adhesive for fabricating graphite/PMR-15 polyimide structures

    NASA Technical Reports Server (NTRS)

    Hill, S. G.; Cushman, J. B.

    1985-01-01

    Tests are conducted to measure shear strength, shear modulus and flatwise tensile strength of the A7F (amide-imide modified LARC-13) adhesive system. An investigation is also conducted to determine the effect of geometric material parameters, and elevated temperature on the static strength of standard joints. Single-lap and double-lap composite joints, and single, double and step lap composite to metal joints are characterized. A series of advanced joints consisting of preformed adherends, adherends with scalloped edges and joints with hybrid interface plies are tested and compared to baseline single and double-lap designs.

  2. Joining of polypropylene/polypropylene and glass fiber reinforced polypropylene composites

    NASA Astrophysics Data System (ADS)

    Zhang, Jianguang

    Joining behavior of polypropylene (PP) to PP and long glass fiber reinforced polypropylene (LFT) to LFT were investigated. Adhesive bonding was used to join PP/PP. Both adhesive bonding and ultrasonic welding were used to join LFT/LFT. Single-lap shear testing and low velocity impact (LVI) testing were used to evaluate the performance of bonded structures. The two-part acrylic adhesive DP8005 was determined to be the best among the three adhesive candidates, which was attributed to its low surface energy. The impact resistance of LFT/LFT joints, normalized with respect to thickness, was higher than that of PP/PP joints because of higher stiffness of LFT/LFT joints. The stress states in the adhesive layer of adhesively bonded structures were analyzed using ANSYS and LS-DYNA to simulate the single-lap shear testing and LVI testing, respectively. The shear and peel stresses peaked at the edges of the adhesive layer. Compared to LFT/LFT joints, higher peel stress occurred in the adhesive layer in the PP/PP joints in tension. Impact response of adhesively bonded structures as evaluated by LS-DYNA showed good agreement with the experimental results. The effect of weld time and weld pressure on the shear strength of ultrasonically welded LFT/LFT was evaluated. With higher weld pressure, less time was required to obtain a complete weld. At longer weld times, lower weld pressure was required. From the 15 weld conditions studied, a weld map was obtained that provides conditions to achieve a complete weld. Nanoindentation was used to evaluate the effect of ultrasonic weld on the modulus and hardness of the PP matrix. Modulus and hardness of the PP matrix were slightly decreased by ultrasonic welding possibly due to the decrease in the molecular weight. The temperature profile in LFT/LFT in the transverse direction during ultrasonic welding was analyzed by two ANSYS-based thermal models: (a) one in which heat generated by interfacial friction was treated as a heat flux and (b) one in which heat was generated in a thin slab at the interface. The weld map obtained from the thin slab model was closer to the one obtained experimentally.

  3. Composition.

    ERIC Educational Resources Information Center

    Nemanich, Donald, Ed.

    1974-01-01

    The articles in this special issue of the "Illinois English Bulletin" concern the state of composition instruction at the secondary and college levels. The titles and authors are "Monologues or Dialogues? A Plea for Literacy" by Dr. Alfred J. Lindsey, "Teaching Composition: Curiouser and Curiouser" by Denny Brandon, and "Teaching Writing to High…

  4. The mechanics and tribology of fretting fatigue with application to riveted lap joints

    NASA Astrophysics Data System (ADS)

    Szolwinski, Matthew Paul

    Fretting is the synergistic combination of wear, corrosion, and fatigue damage mechanisms driven by the partial slip of contacting surfaces. The surface microslip and near-surface contact stresses associated with fretting can lead to severe reduction in service lifetimes of contacting components as diversified as bearings, turbine blades and mechanically-fastened joints, both structural and biological. This tribologically induced degradation has come under close scrutiny by those responsible for maintaining aging fleets of both commercial and military aircraft. Thus a critical need exists for predicting fretting crack nucleation in riveted aluminum. aircraft joints. Fulfilling this need requires characterizing both the near-surface mechanics and intimately-related tribology of fretting. To this end, a well characterized experimental setup has been developed to generate carefully controlled and monitored fretting contacts to investigate the nature of the near-surface conditions. Included in this investigation were in-situ observations of the fretting contact stress field via a non-invasive thermal imaging technique and a characterization of the evolution of friction under partial slip conditions. With specific qualitative and quantitative understanding of these near-surface conditions, a series of fretting fatigue experiments have been conducted to validate a mechanics-based model for predicting fretting fatigue crack nucleation. Finally, efforts have been directed toward extending this understanding of fretting crack nucleation to riveted aircraft structure through modeling of the riveting process and a related experimental program designed to link riveting process parameters and fretting damage in single-lap joint structures. This work focuses specifically on determination of the residual stresses induced during rivet installation and the morphological characterization of fretting fatigue damage in the riveted test specimens manufactured under controlled conditions.

  5. Analytical modeling of composite steel-concrete frame systems 

    E-print Network

    Atahan, Ali Osman

    1996-01-01

    of reinforced concrete or composite steel shapes encased in reinforced concrete (SRC), structural steel beams, and composite beam-column joints. To facilitate the modeling of inelastic deformations in joint regions, a panel element capable of representing joint...

  6. Analytical Study on Adhesively Bonded Joints Using Peeling Test and Symmetric Composite Models Based on Bernoulli-Euler and Timoshenko Beam Theories for Elastic and Viscoelastic Materials

    E-print Network

    Su, Ying-Yu

    2012-02-14

    Adhesively bonded joints have been investigated for several decades. In most analytical studies, the Bernoulli-Euler beam theory is employed to describe the behaviour of adherends. In the current work, three analytical models are developed...

  7. Simulation and Analysis of Residual Stress in the Graded Interlayer of MoSi 2 Composite\\/316L Stainless Steel Joint

    Microsoft Academic Search

    Jinfu Xu; Haifei Wu; Xuebin Zhang; Youjin Fei; Yifu Ye; Wen Li

    2008-01-01

    We reported the simulation and the analysis of the residual stress within the graded interlayered joints of MoSi2 to 316L stainless steel fabricated by spark plasma-sintering (SPS) technique. The residual stress in the joints was analyzed\\u000a by the finite element ANSYS code. The results show that the maximum radial and axial residual tension stresses first decrease\\u000a and then increase with

  8. Method of forming a joint

    DOEpatents

    Butt, Darryl Paul; Cutler, Raymond Ashton; Rynders, Steven Walton; Carolan, Michael Francis

    2006-08-22

    A method of joining at least two sintered bodies to form a composite structure, including providing a first multicomponent metallic oxide having a perovskitic or fluorite crystal structure; providing a second sintered body including a second multicomponent metallic oxide having a crystal structure of the same type as the first; and providing at an interface a joint material containing at least one metal oxide containing at least one metal identically contained in at least one of the first and second multicomponent metallic oxides. The joint material is free of cations of Si, Ge, Sn, Pb, P and Te and has a melting point below the sintering temperatures of both sintered bodies. The joint material is heated to a temperature above the melting point of the metal oxide(s) and below the sintering temperatures of the sintered bodies to form the joint. Structures containing such joints are also disclosed.

  9. ACEE composite structures technology

    NASA Technical Reports Server (NTRS)

    Klotzsche, M. (compiler)

    1984-01-01

    The NASA Aircraft Energy Efficiency (ACEE) Composite Primary Aircraft Structures Program has made significant progress in the development of technology for advanced composites in commercial aircraft. Commercial airframe manufacturers have demonstrated technology readiness and cost effectiveness of advanced composites for secondary and medium primary components and have initiated a concerted program to develop the data base required for efficient application to safety-of-flight wing and fuselage structures. Oral presentations were compiled into five papers. Topics addressed include: damage tolerance and failsafe testing of composite vertical stabilizer; optimization of composite multi-row bolted joints; large wing joint demonstation components; and joints and cutouts in fuselage structure.

  10. Composites

    NASA Astrophysics Data System (ADS)

    Chmielewski, M.; Nosewicz, S.; Pietrzak, K.; Rojek, J.; Strojny-N?dza, A.; Mackiewicz, S.; Dutkiewicz, J.

    2014-11-01

    It is commonly known that the properties of sintered materials are strongly related to technological conditions of the densification process. This paper shows the sintering behavior of a NiAl-Al2O3 composite, and its individual components sintered separately. Each kind of material was processed via the powder metallurgy route (hot pressing). The progress of sintering at different stages of the process was tested. Changes in the microstructure were examined using scanning and transmission electron microscopy. Metal-ceramics interface was clean and no additional phases were detected. Correlation between the microstructure, density, and mechanical properties of the sintered materials was analyzed. The values of elastic constants of NiAl/Al2O3 were close to intermetallic ones due to the volume content of the NiAl phase particularly at low densities, where small alumina particles had no impact on the composite's stiffness. The influence of the external pressure of 30 MPa seemed crucial for obtaining satisfactory stiffness for three kinds of the studied materials which were characterized by a high dense microstructure with a low number of isolated spherical pores.

  11. Joint Projects / Joint Seminars October 2013

    E-print Network

    Fuchs, Clemens

    Joint Projects / Joint Seminars October 2013 Information Sheet Bilateral Programs (MoU) ­ Joint Projects (JP) / Joint Seminars (JS) FWF has signed bilateral agreements ­ so called "Memorandums of Understanding" (MoU) ­ with several international partner organisations. These agreements usually aim at jointly

  12. Commentary: With Shifting Joints Torsten Anders

    E-print Network

    Miranda, Eduardo Reck

    the listener. I applied virtual instruments, physical models comprised of cells and their connections With Shifting Joints Instrumentation Eight-channel tape piece Duration approx. 11 min. Date of Composition-channel tape piece With Shifting Joints, I composed instrumental articula- tions and placed them around

  13. Deformation behavior of model MMC scarf joints

    Microsoft Academic Search

    D. D Brink; J. C Mailand; C. G Levi; F. A Leckie

    2000-01-01

    The mechanical response of metal interlayers constrained between two fiber-reinforced MMC (metal–matrix composites) sub-elements was investigated. The fibers were polycrystalline Al2O3, discontinuous at the joint, embedded in Al–4.5Mg, that was continuous through the joint and constituted both the composite matrix and the interlayer material. The specimens were produced by pressurized melt infiltration and comprised interlayers oriented from 0 to 75°

  14. Joint assembly

    NASA Technical Reports Server (NTRS)

    Wilson, Andrew (Inventor); Punnoose, Andrew (Inventor); Strausser, Katherine (Inventor); Parikh, Neil (Inventor)

    2010-01-01

    A joint assembly is provided which includes a drive assembly and a swivel mechanism. The drive assembly features a motor operatively associated with a plurality of drive shafts for driving auxiliary elements, and a plurality of swivel shafts for pivoting the drive assembly. The swivel mechanism engages the swivel shafts and has a fixable element that may be attached to a foundation. The swivel mechanism is adapted to cooperate with the swivel shafts to pivot the drive assembly with at least two degrees of freedom relative to the foundation. The joint assembly allows for all components to remain encased in a tight, compact, and sealed package, making it ideal for space, exploratory, and commercial applications.

  15. Improved microstructure and mechanical properties in gas tungsten arc welded aluminum joints by using graphene nanosheets/aluminum composite filler wires.

    PubMed

    Fattahi, M; Gholami, A R; Eynalvandpour, A; Ahmadi, E; Fattahi, Y; Akhavan, S

    2014-09-01

    In the present study, different amounts of graphene nanosheets (GNSs) were added to the 4043 aluminum alloy powders by using the mechanical alloying method to produce the composite filler wires. With each of the produced composite filler wires, one all-weld metal coupon was welded using the gas tungsten arc (GTA) welding process. The microstructure, mechanical properties and fracture surface morphology of the weld metals have been evaluated and the results are compared. As the amount of GNSs in the composition of filler wire is increased, the microstructure of weld metal was changed from the dendritic structure to fine equiaxed grains. Furthermore, the tensile strength and microhardness of weld metal was improved, and is attributed to the augmented nucleation and retarded growth. From the results, it was seen that the GNSs/Al composite filler wire can be used to improve the microstructure and mechanical properties of GTA weld metals of aluminum and its alloys. PMID:24981209

  16. Joint x-ray

    MedlinePLUS

    X-ray - joint; Arthrography; Arthrogram ... x-ray technologist will help you position the joint to be x-rayed on the table. Once in place, pictures are taken. The joint may be moved into other positions for more ...

  17. Joint Aspiration (Arthrocentesis)

    MedlinePLUS

    ... the joint. It is usually due to a bacterial infection in the joint. Joint aspiration helps to diagnose ... at the time of the test. If a bacterial infection such as septic arthritis is suspected, a culture ...

  18. Joint Instability and Osteoarthritis

    PubMed Central

    Blalock, Darryl; Miller, Andrew; Tilley, Michael; Wang, Jinxi

    2015-01-01

    Joint instability creates a clinical and economic burden in the health care system. Injuries and disorders that directly damage the joint structure or lead to joint instability are highly associated with osteoarthritis (OA). Thus, understanding the physiology of joint stability and the mechanisms of joint instability-induced OA is of clinical significance. The first section of this review discusses the structure and function of major joint tissues, including periarticular muscles, which play a significant role in joint stability. Because the knee, ankle, and shoulder joints demonstrate a high incidence of ligament injury and joint instability, the second section summarizes the mechanisms of ligament injury-associated joint instability of these joints. The final section highlights the recent advances in the understanding of the mechanical and biological mechanisms of joint instability-induced OA. These advances may lead to new opportunities for clinical intervention in the prevention and early treatment of OA. PMID:25741184

  19. The joint intersection probability

    Microsoft Academic Search

    Y. H. Hatzor; A. Feintuch

    2005-01-01

    In this paper a practical method to apply block theory is presented. Block theory provides the removable joint pyramids from a given free surface regardless of the number of joints in any joint intersection. While robust, the application of the theory in real practice is hampered by the large outcome space of possibly removable joint pyramids consisting of k mutually

  20. Joint analysis of quantitative trait loci and major-effect causative mutations affecting meat quality and carcass composition traits in pigs

    PubMed Central

    2011-01-01

    Background Detection of quantitative trait loci (QTLs) affecting meat quality traits in pigs is crucial for the design of efficient marker-assisted selection programs and to initiate efforts toward the identification of underlying polymorphisms. The RYR1 and PRKAG3 causative mutations, originally identified from major effects on meat characteristics, can be used both as controls for an overall QTL detection strategy for diversely affected traits and as a scale for detected QTL effects. We report on a microsatellite-based QTL detection scan including all autosomes for pig meat quality and carcass composition traits in an F2 population of 1,000 females and barrows resulting from an intercross between a Pietrain and a Large White-Hampshire-Duroc synthetic sire line. Our QTL detection design allowed side-by-side comparison of the RYR1 and PRKAG3 mutation effects seen as QTLs when segregating at low frequencies (0.03-0.08), with independent QTL effects detected from most of the same population, excluding any carrier of these mutations. Results Large QTL effects were detected in the absence of the RYR1 and PRKGA3 mutations, accounting for 12.7% of phenotypic variation in loin colour redness CIE-a* on SSC6 and 15% of phenotypic variation in glycolytic potential on SSC1. We detected 8 significant QTLs with effects on meat quality traits and 20 significant QTLs for carcass composition and growth traits under these conditions. In control analyses including mutation carriers, RYR1 and PRKAG3 mutations were detected as QTLs, from highly significant to suggestive, and explained 53% to 5% of the phenotypic variance according to the trait. Conclusions Our results suggest that part of muscle development and backfat thickness effects commonly attributed to the RYR1 mutation may be a consequence of linkage with independent QTLs affecting those traits. The proportion of variation explained by the most significant QTLs detected in this work is close to the influence of major-effect mutations on the least affected traits, but is one order of magnitude lower than effect on variance of traits primarily affected by these causative mutations. This suggests that uncovering physiological traits directly affected by genetic polymorphisms would be an appropriate approach for further characterization of QTLs. PMID:21875434

  1. Identifying compositional and structural changes in spongy and subchondral bone from the hip joints of patients with osteoarthritis using Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Buchwald, Tomasz; Niciejewski, Krzysztof; Kozielski, Marek; Szybowicz, Miros?aw; Siatkowski, Marcin; Krauss, Hanna

    2012-01-01

    Raman microspectroscopy was used to examine the biochemical composition and molecular structure of extracellular matrix in spongy and subchondral bone collected from patients with clinical and radiological evidence of idiopathic osteoarthritis of the hip and from patients who underwent a femoral neck fracture, as a result of trauma, without previous clinical and radiological evidence of osteoarthritis. The objectives of the study were to determine the levels of mineralization, carbonate accumulation and collagen quality in bone tissue. The subchondral bone from osteoarthritis patients in comparison with control subject is less mineralized due to a decrease in the hydroxyapatite concentration. However, the extent of carbonate accumulation in the apatite crystal lattice increases, most likely due to deficient mineralization. The alpha helix to random coil band area ratio reveals that collagen matrix in subchondral bone is more ordered in osteoarthritis disease. The hydroxyapatite to collagen, carbonate apatite to hydroxyapatite and alpha helix to random coil band area ratios are not significantly changed in the differently loaded sites of femoral head. The significant differences also are not visible in mineral and organic constituents' content in spongy bone beneath the subchondral bone in osteoarthritis disease.

  2. The use of nickel/aluminum explosively reactive nanolayers as localized heat sources in solder joints

    NASA Astrophysics Data System (ADS)

    Tong, Michael Shou-Ming

    Although solder reflow continues to be the current state of the art in joining technology, conventional reflow makes use of furnace heating, in which all components must be exposed to temperatures higher than the melting temperature of the solder. Damaging temperature sensitive components and thermal stresses involved in joining materials of different thermal expansion coefficients are critical drawbacks in using furnace heating. An alternative heat source is provided by Ni/Al reactive nanolayer foils, which is a material comprised of thousands of alternating, nanoscale layers of Al and Ni. A small pulse of energy in the form of an electric spark ignites the reaction by initiating interlayer atomic diffusion. The reaction between these layers is exothermic, releasing enough heat to allow the reaction to propagate through the remainder of the sample. Due to its shape and localized nature of heat released, solder can be melted without heating layers beyond the solder, such as temperature sensitive bond components. In this study, a process is developed to integrate Ni/Al reactive nanolayer foils into bond structures using materials in current technologies. Si/solder/Si and Cu/solder/Cu solder joints are fabricated by reactive nanolayer soldering and are used to study the microstructure and mechanical properties. The microstructural and chemical analysis are performed using scanning and transmission electron microscopy and as well as X-Ray diffraction and energy dispersive analysis, respectively. Single-lap shear testing, through-thickness tensile testing, in-situ nanocompression, and nanoindentation are used to characterize the mechanical strength. Ni/Al nanolayers become a single phase, nanocrystalline NiAl phase as a result of the explosive reaction. The wetting of Sn-based solders is good on this layer, as evidenced by the interlocking branched microstructure as well as the formation of Ni3Sn4 at the interface. A joint shear strength of approximately 30 MPa was yielded when the initial temperature was 70°C and the applied pressure was 15 MPa. In-situ nanocompression results show the direct observation of <110> slip and nanoindentation analysis showed that the NiAI layer has large compressive residual stress.

  3. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1979-01-01

    A multifaceted program is described in which aeronautical, mechanical, and materials engineers interact to develop composite aircraft structures. Topics covered include: (1) the design of an advanced composite elevator and a proposed spar and rib assembly; (2) optimizing fiber orientation in the vicinity of heavily loaded joints; (3) failure mechanisms and delamination; (4) the construction of an ultralight sailplane; (5) computer-aided design; finite element analysis programs, preprocessor development, and array preprocessor for SPAR; (6) advanced analysis methods for composite structures; (7) ultrasonic nondestructive testing; (8) physical properties of epoxy resins and composites; (9) fatigue in composite materials, and (10) transverse thermal expansion of carbon/epoxy composites.

  4. Design\\/analysis of the JWST ISIM bonded joints for survivability at cryogenic temperatures

    Microsoft Academic Search

    Andrew Bartoszyk; John Johnston; Charles Kaprielian; Jonathan Kuhn; Cengiz Kunt; Benjamin Rodini; Daniel Young

    2005-01-01

    A major design and analysis challenge for the JWST ISIM structure is thermal survivability of metal\\/composite adhesively bonded joints at the cryogenic temperature of 30K (-405°F). Current bonded joint concepts include internal invar plug fittings, external saddle titanium\\/invar fittings and composite gusset\\/clip joints all bonded to hybrid composite tubes (75mm square) made with M55J\\/954-6 and T300\\/954-6 prepregs. Analytical experience and

  5. Arch & Chord Joint Detail; Crossbracing Center Joint Detail; Chord, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Arch & Chord Joint Detail; Crossbracing Center Joint Detail; Chord, Panel Post, Tie & Diagonal Brace Joint Detail; Chord, Panel Post, Tie & Crossbracing Joint Detail - Dunlapsville Covered Bridge, Spanning East Fork Whitewater River, Dunlapsville, Union County, IN

  6. Temporomandibular Joint Dysfunction

    MedlinePLUS

    The temporomandibular joint (TMJ) connects your jaw to the side of your head. When it works well, it enables you to ... For people with TMJ dysfunction, problems with the joint and muscles around it may cause Pain that ...

  7. The effect of controlled shot peening on fusion welded joints

    Microsoft Academic Search

    Nur Azida Che Lah; Aidy Ali; Napsiah Ismail; Lim Poon Chai; Abdul Aziz Mohamed

    2010-01-01

    This work examines the effect of controlled shot peening (CSP) treatment on the fatigue strength of an ASTM A516 grade 70 carbon steel welded joint. Metallurgical modifications, hardness, elemental compositions, and internal discontinuities, such as porosity, inclusions, lack of penetration, and undercut found in treated and untreated fusion welded joints, were characterized. The fatigue results of as-welded and peened skimmed

  8. Sacroiliac joint pain - aftercare

    MedlinePLUS

    The sacroiliac joint (SIJ) is a term used to describe the place where the sacrum and the iliac bones join. The ... The main purpose of the joint is to connect the spine and the pelvis. As a result, there is very little movement at the sacroiliac joint. Listed ...

  9. Hybrid CFRP\\/titanium bolted joints: Performance assessment and application to a spacecraft payload adaptor

    Microsoft Academic Search

    A. Fink; P. P. Camanho; J. M. Andrés; E. Pfeiffer; A. Obst

    2010-01-01

    This paper presents an experimental investigation of the mechanical response and the industrial manufacturability of CFRP–titanium hybrid laminates using the example of a spacecraft payload adaptor. The local hybridization with metal within a bolted joint region of composite laminates is proven to be an effective method of increasing the mechanical joint efficiency of highly loaded bolted joints. High-strength titanium foils

  10. A Study of the Effect of Adhesive and Matrix Stiffnesses on the Axial, Normal, and Shear Stress Distributions of a Boron-epoxy Reinforced Composite Joint. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Howell, W. E.

    1974-01-01

    The mechanical properties of a symmetrical, eight-step, titanium-boron-epoxy joint are discussed. A study of the effect of adhesive and matrix stiffnesses on the axial, normal, and shear stress distributions was made using the finite element method. The NASA Structural Analysis Program (NASTRAN) was used for the analysis. The elastic modulus of the adhesive was varied from 345 MPa to 3100 MPa with the nominal value of 1030 MPa as a standard. The nominal values were used to analyze the stability of the joint. The elastic moduli were varied to determine their effect on the stresses in the joint.

  11. Design/Analysis of the JWST ISIM Bonded Joints for Survivability at Cryogenic Temperatures

    NASA Technical Reports Server (NTRS)

    Bartoszyk, Andrew; Johnston, John; Kaprielian, Charles; Kuhn, Jonathan; Kunt, Cengiz; Rodini,Benjamin; Young, Daniel

    1990-01-01

    A major design and analysis challenge for the JWST ISIM structure is thermal survivability of metal/composite bonded joints below the cryogenic temperature of 30K (-405 F). Current bonded joint concepts include internal invar plug fittings, external saddle titanium/invar fittings and composite gusset/clip joints all bonded to M55J/954-6 and T300/954-6 hybrid composite tubes (75mm square). Analytical experience and design work done on metal/composite bonded joints at temperatures below that of liquid nitrogen are limited and important analysis tools, material properties, and failure criteria for composites at cryogenic temperatures are sparse in the literature. Increasing this challenge is the difficulty in testing for these required tools and properties at cryogenic temperatures. To gain confidence in analyzing and designing the ISIM joints, a comprehensive joint development test program has been planned and is currently running. The test program is designed to produce required analytical tools and develop a composite failure criterion for bonded joint strengths at cryogenic temperatures. Finite element analysis is used to design simple test coupons that simulate anticipated stress states in the flight joints; subsequently the test results are used to correlate the analysis technique for the final design of the bonded joints. In this work, we present an overview of the analysis and test methodology, current results, and working joint designs based on developed techniques and properties.

  12. Adhesion study of thermoplastic polyimides with Ti-6Al-4V alloy and PEEK-graphite composites

    SciTech Connect

    Yoon Taeho.

    1991-01-01

    High glass transition (e.g. 360C) melt processable thermoplastic polyimide homopolymers and poly(imide-siloxane) segmented copolymers were prepared from a number of diamines and dianhydrides via solution imidization, polydimethylsilxane segment incorporation and molecular weight control with non-reactive phthalimide end-groups. The adhesive bond performance of these polyimides was investigated as a function of molecular weight, siloxane incorporation, residual solvent, test temperature, and polyimide structure via single-lap shear samples prepared from treated Ti-6Al-4V alloy adherends and compression-molded film adhesives of scrim-cloth adhesives. The adhesive bond strengths increased greatly with siloxane-segment incorporation at 10, 20 and 30 wt% and decreased slightly with total polymer molecular weight. As the test temperature was increased, adhesive bond strength increased, decreased or showed a maximum at some temperatures depending on the polyimide structure and siloxane content. The poly(imide-30% siloxane) segmented copolymer and a miscible poly(ether-imide) also demonstrated excellent adhesive bond strength with poly(arylene ether ketone) PEEK{reg sign}-graphite composites.

  13. Mechanics of Suture Joints

    NASA Astrophysics Data System (ADS)

    Li, Yaning; Song, Juha; Ortiz, Christine; Boyce, Mary; Ortiz group/DMSE/MIT Team; Boyce group/ME/MIT Team

    2011-03-01

    Biological sutures are joints which connect two stiff skeletal or skeletal-like components. These joints possess a wavy geometry with a thin organic layer providing adhesion. Examples of biological sutures include mammalian skulls, the pelvic assembly of the armored fish Gasterosteus aculeatus (the three-spined stickleback), and the suture joints in the shell of the red-eared slider turtle. Biological sutures allow for movement and compliance, control stress concentrations, transmit loads, reduce fatigue stress and absorb energy. In this investigation, the mechanics of the role of suture geometry in providing a naturally optimized joint is explored. In particular, analytical and numerical micromechanical models of the suture joint are constructed. The anisotropic mechanical stiffness and strength are studied as a function of suture wavelength, amplitude and the material properties of the skeletal and organic components, revealing key insights into the optimized nature of these ubiquitous natural joints.

  14. Campylobacter Prosthetic Joint Infection

    PubMed Central

    Vasoo, Shawn; Schwab, Jeramy J.; Cunningham, Scott A.; Robinson, Trisha J.; Cass, Joseph R.; Berbari, Elie F.; Walker, Randall C.; Osmon, Douglas R.

    2014-01-01

    A 75-year-old man was diagnosed with probable Campylobacter jejuni prosthetic knee infection after a diarrheal illness. Joint aspirate and operative cultures were negative, but PCR of prosthesis sonicate fluid was positive, as was stool culture. Nineteen additional cases of Campylobacter prosthetic joint infection reported in the literature are reviewed. PMID:24523462

  15. Joint Newspaper Operating Agreements.

    ERIC Educational Resources Information Center

    Parsons, Marie

    The number of competing daily newspapers in American cities has dwindled until only about 50 cities boast two papers. Of the newspapers in those cities, 23 now maintain separate editorial operations but have joint printing, advertising, and circulation departments. The concept of joint operation is 50 years old, dating from the Depression years…

  16. Compound solder joints

    NASA Technical Reports Server (NTRS)

    Batista, R. I.; Simonson, R. B.

    1976-01-01

    Joining technique prevents contamination, may be used to join dissimilar metal tubes, minimizes fluid and gas entrapment, expedites repairs, and can yield joints having leakage rates less than 0.000001 standard cubic cm He/min. Components of joint are solder sleeve, two solder rings, Teflon sleeve, and tubing to be joined.

  17. Acromioclavicular joint disease.

    PubMed

    Mcdonald, Scott; Hopper, Melanie A

    2015-07-01

    The acromioclavicular joint is an important component of the shoulder girdle experiencing significant loading during normal activities of daily living. The joint is frequently subjected to trauma and as a synovial articulation can become involved in rheumatoid arthritis and the seronegative arthropathies. PMID:26021590

  18. Active brazing carbon\\/carbon composite to TC4 with Cu and Mo composite interlayers

    Microsoft Academic Search

    Youqiong Qin; Jicai Feng

    2009-01-01

    Active filler metal (TiZrNiCu) was used to increase the wettability and Cu and Mo composite interlayers were added to release residual stress and increase the mechanical properties of TC4–C\\/C composite joints. The mechanical properties of the brazed joints were measured by shear strength testing. The effects of brazing parameters on the microstructures of the brazed joint were investigated by SEM,

  19. JOINT ELECTRICAL & COMPUTER ENGINEERING AND

    E-print Network

    JOINT ELECTRICAL & COMPUTER ENGINEERING AND PHYSICS COLLOQUIUM "Speckle Statistics, Coherence confirmation of the increase in the well- defined polarization state of the output radiation. In the joint

  20. Compliant Joints For Robots

    NASA Technical Reports Server (NTRS)

    Kerley, James J., Jr.

    1990-01-01

    Compliant joints devised to accommodate misalignments of tools and/or workpieces with respect to robotic manipulators. Has characteristics and appearance of both universal-joint and cable-spring-type flexible shaft coupling. Compliance derived from elastic properties of short pieces of cable. Compliance of joint determined by lengths, distances between, relative orientations, thickness of strands, number of strands, material, amount of pretwist, and number of short pieces of cable. Worm-drive mechanism used to adjust lengths to vary compliance as needed during operation.

  1. Panel Post & Diagonal Brace Joint Detail; Crossbracing Center Joint ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Panel Post & Diagonal Brace Joint Detail; Crossbracing Center Joint Detail; Chord, Panel Post, Tie Bar, & Diagonal Brace Joint Detail; Chord, Tie Bar, & Crossbracing Joint Detail - Medora Bridge, Spanning East Fork of White River at State Route 235, Medora, Jackson County, IN

  2. Joint fluid Gram stain

    MedlinePLUS

    Gram stain of joint fluid ... result means no bacteria are present on the Gram stain. Note: Normal value ranges may vary slightly ... Abnormal results mean bacteria were seen on the Gram stain. This may be a sign of a ...

  3. Noninfectious joint disease in cattle.

    PubMed

    Nichols, Sylvain; Lardé, Hélène

    2014-03-01

    Osteochondrosis causes variable degrees of joint effusion and lameness. Arthroscopic debridement of the lesions provides the best long-term outcome. Articular fracture or joint instability following collateral ligament rupture causes severe joint effusion and lameness. Internal fixation combined with external coaptation is the treatment of choice. Degenerative joint disease in young animals has a guarded prognosis. Arthroscopy combined with medical therapy may slow down the disease process. Degenerative joint disease involving the distal interphalangeal joint has a good prognosis following joint resection. PMID:24534666

  4. The Composition of Coding Joints Formed in V(D)J Recombination Is Strongly Affected by the Nucleotide Sequence of the Coding Ends and Their Relationship to the Recombination Signal Sequences

    Microsoft Academic Search

    UTHAYASHANKER R. EZEKIEL; TIANHE SUN; GRAZYNA BOZEK; URSULA STORB

    1997-01-01

    V(D)J recombination proceeds in two stages. Precise cleavage at the border of the conserved recombination signal sequences (RSSs) and the coding ends results in flush double-stranded signal ends and coding ends terminating in hairpins. In the second stage, the signal and coding ends are processed into signal and coding joints. Coding ends containing certain nucleotide homopolymers affect the efficiency of

  5. An Affordable Approach for Robust Design of Thick Laminated Composite Structure

    E-print Network

    Chen, Wei

    component for hip joint arthroplasty. The solution yields the robust design of a composite hip implant, composite structure design, hip implant #12;3 1. Introduction With a thick laminated composite structure

  6. A Systems Biology Approach to Synovial Joint Lubrication in Health, Injury, and Disease

    PubMed Central

    Hui, Alexander Y.; McCarty, William J.; Masuda, Koichi; Firestein, Gary S.; Sah, Robert L.

    2013-01-01

    The synovial joint contains synovial fluid (SF) within a cavity bounded by articular cartilage and synovium. SF is a viscous fluid that has lubrication, metabolic, and regulatory functions within synovial joints. SF contains lubricant molecules, including proteoglycan-4 and hyaluronan. SF is an ultrafiltrate of plasma with secreted contributions from cell populations lining and within the synovial joint space, including chondrocytes and synoviocytes. Maintenance of normal SF lubricant composition and function are important for joint homeostasis. In osteoarthritis, rheumatoid arthritis, and joint injury, changes in lubricant composition and function accompany alterations in the cytokine and growth factor environment and increased fluid and molecular transport through joint tissues. Thus, understanding the synovial joint lubrication system requires a multi-faceted study of the various parts of the synovial joint and their interactions. Systems biology approaches at multiple scales are being used to describe the molecular, cellular, and tissue components and their interactions that comprise the functioning synovial joint. Analyses of the transcriptome and proteome of SF, cartilage, and synovium suggest that particular molecules and pathways play important roles in joint homeostasis and disease. Such information may be integrated with physicochemical tissue descriptions to construct integrative models of the synovial joint that ultimately may explain maintenance of health, recovery from injury, or development and progression of arthritis. PMID:21826801

  7. Resistance welding graphite-fiber composites

    NASA Technical Reports Server (NTRS)

    Lamoureux, R. T.

    1980-01-01

    High-strength joints are welded in seconds in carbon-reinfored thermoplastic beams. Resistance-welding electrode applies heat and pressure to joint and is spring-loaded to follow softening material to maintain contact; it also holds parts together for cooling and hardening. Both transverse and longitudinal configurations can be welded. Adhesive bonding and encapsulation are more time consuming methods and introduce additional material into joint, while ultrasonic heating can damage graphite fibers in composite.

  8. New Joint Sealants. Criteria, Design and Materials.

    ERIC Educational Resources Information Center

    Building Research Inst., Inc., Washington, DC.

    Contents include--(1) sealing concrete joints, (2) sealing glass and metal joints, (3) metal and glass joint sealants from a fabricator's viewpoint, (4) a theory of adhesion for joint sealants, (5) geometry of simple joint seals under strain, (6) joint sealant specifications from a manufacturer's viewpoint, (7) joint sealant requirements from an…

  9. Joint for deployable structures

    NASA Technical Reports Server (NTRS)

    Craighead, N. D., II; Preliasco, R. J.; Hult, T. D. (inventors)

    1985-01-01

    A joint is described for connecting a pair of beams to pivot them between positions in alignment or beside one another, which is of light weight and which operates in a controlled manner. The joint includes a pair of fittings and at least one center link having opposite ends pivotally connected to opposite fittings and having axes that pass through centerplates of the fittings. A control link having opposite ends pivotally connected to the different fittings controls their relative orientations, and a toggle assemly holds the fittings in the deployed configuration wherein they are aligned. The fittings have stops that lie on one side of the centerplane opposite the toggle assembly.

  10. Joining of polymer composite materials

    SciTech Connect

    Magness, F.H.

    1990-11-01

    Under ideal conditions load bearing structures would be designed without joints, thus eliminating a source of added weight, complexity and weakness. In reality the need for accessibility, repair, and inspectability, added to the size limitations imposed by the manufacturing process and transportation/assembly requirements mean that some minimum number of joints will be required in most structures. The designer generally has two methods for joining fiber composite materials, adhesive bonding and mechanical fastening. As the use of thermoplastic materials increases, a third joining technique -- welding -- will become more common. It is the purpose of this document to provide a review of the available sources pertinent to the design of joints in fiber composites. The primary emphasis is given to adhesive bonding and mechanical fastening with information coming from documentary sources as old as 1961 and as recent as 1989. A third, shorter section on composite welding is included in order to provide a relatively comprehensive treatment of the subject.

  11. Joints in a Cornstarch Analog

    NSDL National Science Digital Library

    Juliet Crider

    Joints are very important to problems in applied geology (fluid flow, slope stability), but three-dimensional exposures of simple joint sets are not readily accessible from my campus. I developed this exercise based on the experiments of Miller (2001) to give students hands-on practice describing and interpreting joints. For the exercise, I prepare a cornstarch-water mixture a few days in advance and pour it into plastic petri dishes. I add a "flaw" to each dish (typically a small pebble). As the cornstarch dries, vertical joints develop. In class, each group of 3-4 students is provided a petri dish of desiccated cornstarch. Students are asked to draw a map of the joints, paying particular attention to intersection angles. (The joints curve to intersect at 90 degrees.) They determine relative ages of the joints using abutting relationships. (Typically 3-6 generations of joints.) Students next dissect the sample and describe the surface textures of the larger joints and the location of the flaw. The cornstarch produces beautiful plumose structure (hackles). Students then interpret the joint propagation direction from the surface textures, and note the origin of the joint. (Typically, a first- or second-generation joint initiates at the flaw.) Students discuss the role of flaws in the initiation of joints in their groups.

  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. Clad metal joint closure

    SciTech Connect

    Siebert, O.W.

    1985-04-09

    A plasma arc spray overlay of cladding metals is used over joints between clad metal pieces to provide a continuous cladding metal surface. The technique permits applying an overlay of a high melting point cladding metal to a cladding metal surface without excessive heating of the backing metal.

  14. CARTILAGE, BONES, AND JOINTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cartilage is a special type of connective tissue that is of extreme importance in embryonic development, serving as the model upon which true bone is later formed. Cartilage also persists in adult animals, primarily as articular cartilage which cushions the interface between adjacent bones or joint...

  15. Joint publication: Department of

    E-print Network

    Watson, Craig A.

    century. The first law to protect consumers was passed in 1906, and Charles Dadant is credited with getJoint publication: Florida Department of Agriculture & Consumer Services University of Florida Florida Department of Agriculture & Consumer Services 1911 SW 34 Street PO Box 147100 Gainesville, FL

  16. Dolphin Skeleton (Gliding Joint)

    NSDL National Science Digital Library

    Ketan Patel (California State University, Fullerton; )

    2007-07-14

    The dolphin is built to be sleek. Its body is made of almost entirely backbone (a gliding joint) which makes it very flexible under water. The ribs protect the inner organs of the dolphin and the tail beats from side to side, thrusting the animal forward.

  17. Joint Honours AFRICAN STUDIES

    E-print Network

    Miall, Chris

    : The Joint Honours African Studies degree programme at Birmingham is broad, combining arts and social Office - Retail management - Aid work with Save the Children - Probation work - Welfare rights worker - Computer programmer - NGO work in Kurdistan - Work with adults who have learning disabilities - Research

  18. Joint Institute Marine and Atmospheric

    E-print Network

    Hawai'i at Manoa, University of

    Joint Institute for Marine and Atmospheric Research NATIONALOCEA NIC AND ATMOSPHERIC ADMINISTRATION Contribution 00-328 #12;ii This research is funded by Cooperative Agreement Number NA67RJ0154 between the Joint

  19. Tensile Properties, Collagen Content, and Crosslinks in Connective Tissues of the Immature Knee Joint

    Microsoft Academic Search

    Sriram V. Eleswarapu; Donald J. Responte; Kyriacos A. Athanasiou; Alejandro Almarza

    2011-01-01

    BackgroundThe major connective tissues of the knee joint act in concert during locomotion to provide joint stability, smooth articulation, shock absorption, and distribution of mechanical stresses. These functions are largely conferred by the intrinsic material properties of the tissues, which are in turn determined by biochemical composition. A thorough understanding of the structure-function relationships of the connective tissues of the

  20. Hybrid titanium–CFRP laminates for high-performance bolted joints

    Microsoft Academic Search

    P. P. Camanho; A. Fink; A. Obst; S. Pimenta

    2009-01-01

    This paper presents an experimental and numerical investigation of the mechanical response of bolted joints manufactured using new hybrid composite laminates based on the substitution of CFRP plies with titanium plies. The local hybridization of the material is proposed to increase the efficiency of the bolted joints in CFRP structures. Two modeling strategies, based on non-linear finite element methods, are

  1. Cellular Pressure-Actuated Joint

    NASA Technical Reports Server (NTRS)

    McGuire, John R.

    2003-01-01

    A modification of a pressure-actuated joint has been proposed to improve its pressure actuation in such a manner as to reduce the potential for leakage of the pressurizing fluid. The specific joint for which the modification is proposed is a field joint in a reusable solid-fuel rocket motor (RSRM), in which the pressurizing fluid is a mixture of hot combustion gases. The proposed modification could also be applicable to other pressure-actuated joints of similar configuration.

  2. A Biomimetic Structural Health Monitoring Approach Using Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Liu, Yingtao; Rajadas, Abhishek; Chattopadhyay, Aditi

    2012-07-01

    A self-sensing nanocomposite material has been developed to track the presence of damage in complex composite structures. Multiwalled carbon nanotubes are integrated with polymer matrix to develop a novel bonding material with sensing capabilities. The changes of the piezoresistance in the presence of damage are used to monitor the condition of bonded joints, where the usual bonding material is replaced by the self-sensing nanocomposite. The feasibility of this concept is investigated through experiments conducted on single-lap joints subject to monotonic tensile loading conditions. The results show that the self-sensing nanocomposite is sensitive to crack propagation within the matrix material. An acoustic emission-based sensing technique has been used to validate these results and shows good correlation with damage growth. A digital image correlation system is used to measure the shear strain field in the joint area.

  3. Phase 1 Program Joint Report

    NASA Technical Reports Server (NTRS)

    Nield, George C. (Editor); Vorobiev, Pavel Mikhailovich (Editor)

    1999-01-01

    This report consists of inputs from each of the Phase I Program Joint Working Groups. The Working Groups were tasked to describe the organizational structure and work processes that they used during the program, joint accomplishments, lessons learned, and applications to the International Space Station Program. This report is a top-level joint reference document that contains information of interest to both countries.

  4. Joint Communiqu Progress against the

    E-print Network

    1 Joint Communiqué Progress against the Joint Statement of Cooperation between Kalimantan Timur the Joint Statement of Cooperation of 16 September 2010 designed to develop closer ties between Kalimantan the following areas: Livestock Following the 2010 Livestock Workshop held in Balikpapan, a Kalimantan Timur

  5. Joint Seminar UNIVERSITY OF GEORGIA

    E-print Network

    Wang, Lily

    Joint Seminar UNIVERSITY OF GEORGIA DEPARTMENT OF STATISTICS DEPARTMENT OF EPIDEMIOLOGY longitudinal covariates are involved in the modeling of the survival data. A joint likelihood approach has been data. However, in the presence of left truncation, there are additional challenges for the joint

  6. JOINT PERFORMANCE Guide for Optimum

    E-print Network

    July 2012 JOINT PERFORMANCE Guide for Optimum of Concrete Pavements #12; #12;Guide for Optimum Joint Performance of Concrete Pavements i Technical Report Documentation Page 1. Report No. 2. Report Date Guide for Optimum Joint Performance of Concrete Pavements July 2012 6. Performing

  7. Muscular forces affect the glycosaminoglycan content of joint cartilage.

    PubMed

    Ganse, Bergita; Zange, Jochen; Weber, Tobias; Pohle-Fröhlich, Regina; W Johannes, Bernd; Hackenbroch, Matthias; Rittweger, Jörn; Eysel, Peer; Koy, Timmo

    2015-06-01

    Background and purpose - Unloading alters the thickness of joint cartilage. It is unknown, however, to what extent unloading leads to a loss of glycosaminoglycans (GAGs) in the cartilage tissue. We hypothesized that muscle forces, in addition to axial loading, are necessary to maintain the joint cartilage GAG content of the knee and the upper and lower ankle. Patients and methods - The HEPHAISTOS orthosis was worn unilaterally by 11 men (mean age 31 (23-50) years old) for 56 days. The orthosis reduces activation and force production of the calf muscles while it permits full gravitational loading of the lower leg. MRI measurements of the knee and ankle were taken before the intervention, during the intervention (on day 49), and 14 days after the end of the intervention. Cartilage segmentation was conducted semiautomatically for the knee joint (4 segments) and for the upper (tibio-talar) and lower (subtalar) ankle joints (2 segments each). Linear mixed-effects (LME) models were used for statistical analysis. Results - 8 volunteers completed the MRI experiment. In the lower ankle joint, differences in ?T1 were found between the end of the intervention and 14 days after (p = 0.004), indicating a decrease in GAG content after reloading. There were no statistically significant differences in ?T1 values in the knee and upper ankle joints. Interpretation - Our findings suggest that in addition to gravitational load, muscular forces affect cartilage composition depending on the local distribution of forces in the joints affected by muscle contraction. PMID:25417835

  8. Muscular forces affect the glycosaminoglycan content of joint cartilage

    PubMed Central

    Ganse, Bergita; Zange, Jochen; Weber, Tobias; Pohle-Fröhlich, Regina; Johannes, Bernd W; Hackenbroch, Matthias; Rittweger, Jörn; Eysel, Peer; Koy, Timmo

    2015-01-01

    Background and purpose Unloading alters the thickness of joint cartilage. It is unknown, however, to what extent unloading leads to a loss of glycosaminoglycans (GAGs) in the cartilage tissue. We hypothesized that muscle forces, in addition to axial loading, are necessary to maintain the joint cartilage GAG content of the knee and the upper and lower ankle. Patients and methods The HEPHAISTOS orthosis was worn unilaterally by 11 men (mean age 31 (23–50) years old) for 56 days. The orthosis reduces activation and force production of the calf muscles while it permits full gravitational loading of the lower leg. MRI measurements of the knee and ankle were taken before the intervention, during the intervention (on day 49), and 14 days after the end of the intervention. Cartilage segmentation was conducted semiautomatically for the knee joint (4 segments) and for the upper (tibio-talar) and lower (subtalar) ankle joints (2 segments each). Linear mixed-effects (LME) models were used for statistical analysis. Results 8 volunteers completed the MRI experiment. In the lower ankle joint, differences in ?T1 were found between the end of the intervention and 14 days after (p = 0.004), indicating a decrease in GAG content after reloading. There were no statistically significant differences in ?T1 values in the knee and upper ankle joints. Interpretation Our findings suggest that in addition to gravitational load, muscular forces affect cartilage composition depending on the local distribution of forces in the joints affected by muscle contraction. PMID:25417835

  9. 47 CFR 76.912 - Joint certification.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...912 Joint certification. (a) Franchising authorities may apply for joint...data collection, and ratemaking. Franchising authorities jointly certified to regulate...independent rate decisions. (b) Franchising authorities may apply for joint...

  10. 47 CFR 76.912 - Joint certification.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...912 Joint certification. (a) Franchising authorities may apply for joint...data collection, and ratemaking. Franchising authorities jointly certified to regulate...independent rate decisions. (b) Franchising authorities may apply for joint...

  11. Joint Degrees & Promotion towards European Students

    E-print Network

    Di Pillo, Gianni

    Joint Degrees & Promotion towards European Students 26 June 2014 MATTEA CAPELLI & ALESSANDRA GALLERANO INTERNATIONAL OFFICE #12;Joint Degrees and Promotion towards European students Joint degrees guidelines and template for agreements Support to student participation Promotion of Joint Degrees towards

  12. On Joint Coding for Watermarking and Encryption Neri Merhav

    E-print Network

    Merhav, Neri

    On Joint Coding for Watermarking and Encryption Neri Merhav Department of Electrical Engineering the additional ingredient of protecting the secrecy of the watermark against an unauthorized party, which has in reconstructing the watermark by the legitimate receiver, the compressibility of the composite signal (with

  13. Effect of replacing soybean protein with protein from porcupine joint vetch (Aeschynomene histrix BRA 9690) and stylo (Stylosanthes guianensis Composite) leaf meal on growth performance of native (Moo Lath) Lao pigs.

    PubMed

    Phengsavanh, Phonepaseuth; Lindberg, Jan Erik

    2013-11-01

    The effect of replacing soybean crude protein (CP) with legume leaf meal (LLM) CP on feed intake, growth performance and carcass traits was studied in native female Moo Lath Lao pigs. The diets comprised one traditional diet (T) without soybean meal, one control diet (C) with soybean meal and six diets iso-nitrogenous with diet C in which soybean protein was replaced (33, 66 and 100 % of CP) with LLM CP from porcupine joint vetch (PLM) or Stylosanthes (SLM). Feed and water were offered ad libitum. Replacing soybean CP with LLM CP reduced (P??0.05) on feed conversion ratio (FCR). Increasing the replacement rate of soybean CP with LLM CP had a negative linear effect (P?joint vetch can be used as a CP source to partially replace soybean meal CP in the diet of growing native female Moo Lath Lao pigs. PMID:23846768

  14. Composite drill pipe

    DOEpatents

    Leslie, James C. (Fountain Valley, CA); Leslie, II, James C. (Mission Viejo, CA); Heard, James (Huntington Beach, CA); Truong, Liem (Anaheim, CA), Josephson; Marvin (Huntington Beach, CA), Neubert; Hans (Anaheim, CA)

    2008-12-02

    A composite pipe segment is formed to include tapered in wall thickness ends that are each defined by opposed frustoconical surfaces conformed for self centering receipt and intimate bonding contact within an annular space between corresponding surfaces of a coaxially nested set of metal end pieces. The distal peripheries of the nested end pieces are then welded to each other and the sandwiched and bonded portions are radially pinned. The composite segment may include imbedded conductive leads and the axial end portions of the end pieces are shaped to form a threaded joint with the next pipe assembly that includes a contact ring in one pipe assembly pierced by a pointed contact in the other to connect the corresponding leads across the joint.

  15. Achieving joint benefits from joint implementation

    SciTech Connect

    Moomaw, W.R. [Tufts Univ., Medford, MA (United States)

    1995-11-01

    Joint Implementation (JI) appears to have been born with Applied Energy Services Guatemala project in 1988. That project, to plant 52 million trees, protect existing forests from cutting and fire, and enhance rural development, is being implemented by CARE Guatemala to offset 120 per cent of the emissions of a small coal burning power plant that has been built in Connecticut. Since that time, several utilities and governments have initiated additional projects. Not all of these necessarily consist of tree planting in other countries, but may consist of energy efficiency or energy conservation programs designed to reduce carbon emissions by at least as much as the additional releases from a new facility. All JI projects share the characteristic of linking the release of greenhouse gases in an industrial country with an offset that reduces or absorbs a comparable amount in another country. The emitter in the industrial country is willing to pay for the reduction elsewhere because costs are less than they would be at home.

  16. Laboratory characterization of rock joints

    SciTech Connect

    Hsiung, S.M.; Kana, D.D.; Ahola, M.P.; Chowdhury, A.H.; Ghosh, A. [Southwest Research Inst., San Antonio, TX (United States). Center for Nuclear Waste Regulatory Analyses

    1994-05-01

    A laboratory characterization of the Apache Leap tuff joints under cyclic pseudostatic and dynamic loads has been undertaken to obtain a better understanding of dynamic joint shear behavior and to generate a complete data set that can be used for validation of existing rock-joint models. Study has indicated that available methods for determining joint roughness coefficient (JRC) significantly underestimate the roughness coefficient of the Apache Leap tuff joints, that will lead to an underestimation of the joint shear strength. The results of the direct shear tests have indicated that both under cyclic pseudostatic and dynamic loadings the joint resistance upon reverse shearing is smaller than that of forward shearing and the joint dilation resulting from forward shearing recovers during reverse shearing. Within the range of variation of shearing velocity used in these tests, the shearing velocity effect on rock-joint behavior seems to be minor, and no noticeable effect on the peak joint shear strength and the joint shear strength for the reverse shearing is observed.

  17. Composite structural materials. [fiber reinforced composites for aircraft structures

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberly, S. E.

    1981-01-01

    Physical properties of fiber reinforced composites; structural concepts and analysis; manufacturing; reliability; and life prediction are subjects of research conducted to determine the long term integrity of composite aircraft structures under conditions pertinent to service use. Progress is reported in (1) characterizing homogeneity in composite materials; (2) developing methods for analyzing composite materials; (3) studying fatigue in composite materials; (4) determining the temperature and moisture effects on the mechanical properties of laminates; (5) numerically analyzing moisture effects; (6) numerically analyzing the micromechanics of composite fracture; (7) constructing the 727 elevator attachment rib; (8) developing the L-1011 engine drag strut (CAPCOMP 2 program); (9) analyzing mechanical joints in composites; (10) developing computer software; and (11) processing science and technology, with emphasis on the sailplane project.

  18. Collective and joint intention

    Microsoft Academic Search

    Raimo Tuomela; Joint Intentions

    2000-01-01

    The paper discussed and analyzes collective and joint intentions of various strength. Thus there are subjectively shared collective\\u000a intentions and intersubjectively shared collective intentions as well as collective intentions which are objectively and intersubjectively\\u000a shared. The distinction between collective and private intentions is considered from several points of view. Especially, it\\u000a is emphasized that collective intentions in the full sense

  19. Joint measurements and Bell inequalities

    E-print Network

    Wonmin Son; Erika Andersson; Stephem M. Barnett; M. S. Kim

    2005-09-20

    Joint quantum measurements of non-commuting observables are possible, if one accepts an increase in the measured variances. A necessary condition for a joint measurement to be possible is that a joint probability distribution exists for the measurement. This fact suggests that there may be a link with Bell inequalities, as these will be satisfied if and only if a joint probability distribution for all involved observables exists. We investigate the connections between Bell inequalities and conditions for joint quantum measurements to be possible. Mermin's inequality for the three-particle Greenberger-Horne-Zeilinger state turns out to be equivalent to the condition for a joint measurement on two out of the three quantum systems to exist. Gisin's Bell inequality for three co-planar measurement directions, meanwhile, is shown to be less strict than the condition for the corresponding joint measurement.

  20. Development of a satellite structure with the sandwich T-joint

    Microsoft Academic Search

    Byoung Jung Kim; Dai Gil Lee

    2010-01-01

    In this study, a monocoque satellite structure composed of many composite sandwich panels, which consist of two carbon fiber\\/epoxy composite faces and an aluminum honeycomb core, was designed to reduce structural mass and to improve static and dynamic structural rigidity. To join composite sandwich panels with T-shape joints, a new I-shape side insert, which was fixed inside the composite sandwich

  1. Creep in shear of experimental solder joints

    SciTech Connect

    Tribula, D.; Morris, J.W. Jr.

    1989-09-01

    Thermal fatigue failures of solder joints in electronic devices are a great concern in the electronics industry. Since the fatigue load is often in shear the details of thermal fatigue failure in shear are of particular interest. Recent work indicates that similar failure mechanisms operate in both thermal fatigue in shear and unidirectional creep in shear. Additionally, since the operative temperatures during thermal fatigue represent high solder homologous temperatures, creep deformation is certainly involved. These factors and the relative ease of conducting creep experiments encourage the study of solder joints under shear creep conditions. This work presents steady state shear creep rate vs shear stress data for several solder compositions, including the binary eutectic alloy and Pb-Sn alloyed with small amounts of Bi, Cd, In, and Sb, in a joint configuration. These data indicate that conventional creep mechanisms operate in the temperature and shear strain rate ranges studied. Extensive microstructural information is also reported. The microstructural evolution under creep conditions indicates that the instability of the as-cast binary Pb-Sn eutectic microstructure initiates creep failure. Changes of the as-solidified microstructure with the third element addition are reported as are the microstructural responses of each of these alloys to creep deformation. The efficacy of postponing the microstructural instability with the addition of small amounts of ternary elements is discussed. 27 refs., 13 figs., 1 tab.

  2. On representations for joint moments using a joint coordinate system.

    PubMed

    O'Reilly, Oliver M; Sena, Mark P; Feeley, Brian T; Lotz, Jeffrey C

    2013-11-01

    In studies of the biomechanics of joints, the representation of moments using the joint coordinate system has been discussed by several authors. The primary purpose of this technical brief is to emphasize that there are two distinct, albeit related, representations for moment vectors using the joint coordinate system. These distinct representations are illuminated by exploring connections between the Euler and dual Euler bases, the "nonorthogonal projections" presented in a recent paper by Desroches et al. (2010, "Expression of Joint Moment in the Joint Coordinate System," ASME J. Biomech. Eng., 132(11), p. 11450) and seminal works by Grood and Suntay (Grood and Suntay, 1983, "A Joint Coordinate System for the Clinical Description of Three-Dimensional Motions: Application to the Knee," ASME J. Biomech. Eng., 105(2), pp. 136-144) and Fujie et al. (1996, "Forces and Moment in Six-DOF at the Human Knee Joint: Mathematical Description for Control," Journal of Biomechanics, 29(12), pp. 1577-1585) on the knee joint. It is also shown how the representation using the dual Euler basis leads to straightforward definition of joint stiffnesses. PMID:24008987

  3. Composite Nonwovens

    Microsoft Academic Search

    Dipayan Das; Arun Kumar Pradhan; R. Chattopadhyay; S. N. Singh

    2012-01-01

    The term ‘composite nonwovens’ refers to a category of materials different from ‘nonwoven composites’, which consist of a resinous matrix reinforced by an embedded nonwoven fabric. Many scientists would like to rename ‘composite nonwovens’ as ‘soft nonwoven composites’ and ‘nonwoven composites’ as ‘hard nonwoven composites’. Composite nonwovens are created by a modern and innovative industry employing nonwoven technologies to bring

  4. Posttraumatic Temporomandibular Joint Disorders

    PubMed Central

    Giannakopoulos, Helen E.; Quinn, Peter D.; Granquist, Eric; Chou, Joli C.

    2009-01-01

    The temporomandibular joint (TMJ) has many essential functions. None of its components are exempt from injury. Facial asymmetry, malocclusion, disturbances in growth, osteoarthritis, and ankylosis can manifest as complications from trauma to the TMJ. The goals of initial treatment include achievement of pretraumatic function, restoration of facial symmetry, and resolution of pain. These same objectives hold true for late repairs and reconstruction of the TMJ apparatus. Treatment is demanding, and with opposing approaches. The following article explores various treatment options for problems presenting as a result of a history of trauma to the TMJ. PMID:22110802

  5. Joint bone radiobiology workshop

    SciTech Connect

    Tomich, P.A. (ed.)

    1991-01-01

    The Joint Bone Radiobiology Workshop was held on July 12--13, 1991 in Toronto, Canada. This document contains the papers presented at the meeting. The five sections were: Dose-effects, Endogenous Cofactors, Tumorigenesis, New Methods and Medical Implications. The papers covered risk assessment, tissue distribution of radionuclides, lifetime studies, biological half-lifes, the influence of age at time of exposure, tumor induction by different radionuclides, microscopic localization of radionuclides, and nuclear medicine issues including tissue distribution in the skeleton and bone marrow transplantation. (MHB)

  6. Patellofemoral Joint Disorders

    PubMed Central

    Stalker, Robert

    1987-01-01

    Knee pain is a common presenting complaint by athletes and the general population. Disorders of the patellofemoral joint are responsible for most of these disorders. Abnormal patellar tracking is thought to be the principal cause. Patellar tracking is influenced by a number of dynamic and static factors. These can be assessed with a careful history and physical examination. A treatment program can be designed to alter the precipitating factors. Lower-extremity malalignment, principally hyperpronation of the foot, is believed to be a major cause of abnormal patellar tracking. Conservative treatment programs have had successful results, and less emphasis is now being placed on surgical procedures. PMID:21263850

  7. Temporomandibular Joint Disorders

    NSDL National Science Digital Library

    Patient Education Institute

    This patient education program explains temporomandibular joint disorders (TMJ). It reviews the anatomy of the jaw, plus symptoms, causes, diagnosis, and treatment options for TMJ disorders. This resource is a MedlinePlus Interactive Health Tutorial from the National Library of Medicine, designed and developed by the Patient Education Institute. NOTE: This tutorial requires a special Flash plug-in, version 4 or above. If you do not have Flash, you will be prompted to obtain a free download of the software before you start the tutorial. You will also need an Acrobat Reader, available as a free download, in order to view the Reference Summary.

  8. Bladder operated robotic joint

    NASA Technical Reports Server (NTRS)

    Robertson, Glen A. (inventor)

    1993-01-01

    This invention is a robotic joint which is operated by inflatable bladders and which can be used in applications where it is desired to move or hold an object. A support block supports an elongated plate to which is pivotally attached a finger. A tension strip passes over a lever attached to the finger and is attached at its ends to the support block on opposite sides of the plate. Bladders positioned between the plate and the tension strip on opposite sides of the plate can be inflated by pumps to pivot the finger, with one of the bladders being inflated while the other is being deflated.

  9. Metal to ceramic sealed joint

    DOEpatents

    Lasecki, John V. (Livonia, MI); Novak, Robert F. (Farmington Hills, MI); McBride, James R. (Ypsilanti, MI)

    1991-01-01

    A metal to ceramic sealed joint which can withstand wide variations in temperature and maintain a good seal is provided for use in a device adapted to withstand thermal cycling from about 20 to about 1000 degrees C. The sealed joint includes a metal member, a ceramic member having an end portion, and an active metal braze forming a joint to seal the metal member to the ceramic member. The joint is positioned remote from the end portion of the ceramic member to avoid stresses at the ends or edges of the ceramic member. The sealed joint is particularly suited for use to form sealed metal to ceramic joints in a thermoelectric generator such as a sodium heat engine where a solid ceramic electrolyte is joined to metal parts in the system.

  10. Strength of Welded Aircraft Joints

    NASA Technical Reports Server (NTRS)

    Brueggeman, W C

    1937-01-01

    This investigation is a continuation of work started in 1928 and described in NACA-TR-348 which shows that the insertion of gusset plates was the most satisfactory way of strengthening a joint. Additional tests of the present series show that joints of this type could be improved by cutting out the portion of the plate between the intersecting tubes. T and lattice joints in thin-walled tubing 1 1/2 by 0.020 inch have somewhat lower strengths than joints in tubing of greater wall thickness because of failure by local buckling. In welding the thin-walled tubing, the recently developed "carburizing flux" process was found to be the only method capable of producing joints free from cracks. The "magnetic powder" inspection was used to detect cracks in the joints and flaws in the tubing.

  11. OIG targets contractual joint ventures.

    PubMed

    O'Hare, Patrick K

    2003-09-01

    A recent OIG Special Advisory Bulletin raises questions for providers involved in joint ventures. The Bulletin describes several characteristics that the OIG views as potentially suspect, including a referral stream controlled by the provider initiating the joint venture and the use of a wholly owned subsidiary of the provider to bill and collect for services. According to the OIG, profits paid by the subsidiary to the provider owner in such "suspect contractual joint ventures" could constitute illegal remuneration for referrals. PMID:14503145

  12. Joint custody: solution or illusion?

    PubMed

    Benedek, E P; Benedek, R S

    1979-12-01

    Although the phrase "joint custody" is in popular use, the concept lacks standard definitin; parents who express interest in this form of disposition have widely differing objectives and expectations. The authors discuss the need for determining the primary objectives of the parties involved and for exploring the potential for achieving these through joint custody as well as through other alternatives. They examine the benefits of joint custody as well as the risks engendered by this type of arrangement and make a number of specific recommendations. They conclude that joint custody should be considered and explored, together with other available alternatives, and awarded only in appropriate cases. PMID:507203

  13. Biofluid lubrication for artificial joints 

    E-print Network

    Pendelton, Alice Mae

    2009-05-15

    This research investigated biofluid lubrication related to artificial joints using tribological and rheological approaches. Biofluids studied here represent two categories of fluids, base fluids and nanostructured biofluids. ...

  14. Metacarpophalangeal joint arthroscopy: indications revisited.

    PubMed

    Choi, Alexander K Y; Chow, Esther C S; Ho, P C; Chow, Y Y

    2011-08-01

    Arthroscopic surgery has become the gold standard for the diagnosis and treatment of major joint disorders. With advancement in arthroscopic technique, arthroscopy has become feasible in most human joints, even those as small as the finger joints. The metacarpophalangeal joint (MCPJ) can become spacious with simple traction, the intra-articular anatomy is simple, and its major structures can be easily visualized and identified. However, MCPJ arthroscopy has never been popular. This article describes our experience with MCPJ arthroscopy and seeks to establish its role in clinical practice. PMID:21871361

  15. Rotary Joint for Heat Transfer

    NASA Technical Reports Server (NTRS)

    Shauback, R.

    1986-01-01

    Rotary joint exchanges heat between two heat pipes - one rotating and one stationary. Joint accommodates varying heat loads with little temperature drop across interface. According to concept, heat pipe enters center of disklike stationary section of joint. There, wicks in central artery of heat pipe separate into multiple strands that lead to concentric channels on rotaryinterface side of stationary disk. Thin layer of liquid sodium/potassium alloy carries heat from one member of rotary joint to other. Liquid conducts heat efficiently while permitting relative motion between members. Polypropylene rings contain liquid without interfering with rotation.

  16. Jointly Sponsored Research Program

    SciTech Connect

    Everett A. Sondreal; John G. Hendrikson; Thomas A. Erickson

    2009-03-31

    U.S. Department of Energy (DOE) Cooperative Agreement DE-FC26-98FT40321 funded through the Office of Fossil Energy and administered at the National Energy Technology Laboratory (NETL) supported the performance of a Jointly Sponsored Research Program (JSRP) at the Energy & Environmental Research Center (EERC) with a minimum 50% nonfederal cost share to assist industry in commercializing and effectively applying highly efficient, nonpolluting energy systems that meet the nation's requirements for clean fuels, chemicals, and electricity in the 21st century. The EERC in partnership with its nonfederal partners jointly performed 131 JSRP projects for which the total DOE cost share was $22,716,634 (38%) and the nonfederal share was $36,776,573 (62%). Summaries of these projects are presented in this report for six program areas: (1) resource characterization and waste management, (2) air quality assessment and control, (3) advanced power systems, (4) advanced fuel forms, (5) value-added coproducts, and (6) advanced materials. The work performed under this agreement addressed DOE goals for reductions in CO{sub 2} emissions through efficiency, capture, and sequestration; near-zero emissions from highly efficient coal-fired power plants; environmental control capabilities for SO{sub 2}, NO{sub x}, fine respirable particulate (PM{sub 2.5}), and mercury; alternative transportation fuels including liquid synfuels and hydrogen; and synergistic integration of fossil and renewable resources.

  17. Glenohumeral Joint Injections

    PubMed Central

    Gross, Christopher; Dhawan, Aman; Harwood, Daniel; Gochanour, Eric; Romeo, Anthony

    2013-01-01

    Context: Intra-articular injections into the glenohumeral joint are commonly performed by musculoskeletal providers, including orthopaedic surgeons, family medicine physicians, rheumatologists, and physician assistants. Despite their frequent use, there is little guidance for injectable treatments to the glenohumeral joint for conditions such as osteoarthritis, adhesive capsulitis, and rheumatoid arthritis. Evidence Acquisition: We performed a comprehensive review of the available literature on glenohumeral injections to help clarify the current evidence-based practice and identify deficits in our understanding. We searched MEDLINE (1948 to December 2011 [week 1]) and EMBASE (1980 to 2011 [week 49]) using various permutations of intra-articular injections AND (corticosteroid OR hyaluronic acid) and (adhesive capsulitis OR arthritis). Results: We identified 1 and 7 studies that investigated intra-articular corticosteroid injections for the treatment of osteoarthritis and adhesive capsulitis, respectively. Two and 3 studies investigated the use of hyaluronic acid in osteoarthritis and adhesive capsulitis, respectively. One study compared corticosteroids and hyaluronic acid injections in the treatment of osteoarthritis, and another discussed adhesive capsulitis. Conclusion: Based on existing studies and their level of evidence, there is only expert opinion to guide corticosteroid injection for osteoarthritis as well as hyaluronic acid injection for osteoarthritis and adhesive capsulitis. PMID:24427384

  18. Joint collaborative technology experiment

    NASA Astrophysics Data System (ADS)

    Wills, Michael; Ciccimaro, Donny; Yee, See; Denewiler, Thomas; Stroumtsos, Nicholas; Messamore, John; Brown, Rodney; Skibba, Brian; Clapp, Daniel; Wit, Jeff; Shirts, Randy J.; Dion, Gary N.; Anselmo, Gary S.

    2009-05-01

    Use of unmanned systems is rapidly growing within the military and civilian sectors in a variety of roles including reconnaissance, surveillance, explosive ordinance disposal (EOD), and force-protection and perimeter security. As utilization of these systems grows at an ever increasing rate, the need for unmanned systems teaming and inter-system collaboration becomes apparent. Collaboration provides a means of enhancing individual system capabilities through relevant data exchange that contributes to cooperative behaviors between systems and enables new capabilities not possible if the systems operate independently. A collaborative networked approach to development holds the promise of adding mission capability while simultaneously reducing the workload of system operators. The Joint Collaborative Technology Experiment (JCTE) joins individual technology development efforts within the Air Force, Navy, and Army to demonstrate the potential benefits of interoperable multiple system collaboration in a force-protection application. JCTE participants are the Air Force Research Laboratory, Materials and Manufacturing Directorate, Airbase Technologies Division, Force Protection Branch (AFRL/RXQF); the Army Aviation and Missile Research, Development, and Engineering Center Software Engineering Directorate (AMRDEC SED); and the Space and Naval Warfare Systems Center - Pacific (SSC Pacific) Unmanned Systems Branch operating with funding provided by the Joint Ground Robotics Enterprise (JGRE). This paper will describe the efforts to date in system development by the three partner organizations, development of collaborative behaviors and experimentation in the force-protection application, results and lessons learned at a technical demonstration, simulation results, and a path forward for future work.

  19. Low temperature joining of ceramic composites

    DOEpatents

    Barton, Thomas J. (Ames, IA); Anderson, Iver E. (Ames, IA); Ijadi-Maghsoodi, Sina (Ames, IA); Nosrati, Mohammad (Ames, IA); Unal, Ozer (Ames, IA)

    2001-04-10

    A method of joining similar or dissimilar ceramic and ceramic composite materials, such as SiC continuous fiber ceramic composites, at relatively low joining temperatures uses a solventless, three component bonding agent effective to promote mechanical bond toughness and elevated temperature strength to operating temperatures of approximately 1200 degrees C. The bonding agent comprises a preceramic precursor, an aluminum bearing powder, such as aluminum alloy powder, and mixtures of aluminum metal or alloy powders with another powder, and and boron powder in selected proportions. The bonding agent is disposed as an interlayer between similar or dissimilar ceramic or cermaic composite materials to be joined and is heated in ambient air or inert atmosphere to a temperature not exceeding about 1200 degrees C. to form a strong and tough bond joint between the materials. The bond joint produced is characterized by a composite joint microstructure having relatively soft, compliant aluminum bearing particulate regions dispersed in a ceramic matrix.

  20. Low temperature joining of ceramic composites

    DOEpatents

    Barton, T.J.; Anderson, I.E.; Ijadi-Maghsoodi, S.; Nosrati, M.; Unal, O.

    1999-07-13

    A method of joining similar or dissimilar ceramic and ceramic composite materials, such as SiC continuous fiber ceramic composites, at relatively low joining temperatures uses a solventless, three component bonding agent effective to promote mechanical bond toughness and elevated temperature strength to operating temperatures of approximately 1200 C. The bonding agent comprises a preceramic precursor, an aluminum bearing powder, such as aluminum alloy powder, and mixtures of aluminum metal or alloy powders with another powder, and boron powder in selected proportions. The bonding agent is disposed as an interlayer between similar or dissimilar ceramic or ceramic composite materials to be joined and is heated in ambient air or inert atmosphere to a temperature not exceeding about 1200 C to form a strong and tough bond joint between the materials. The bond joint produced is characterized by a composite joint microstructure having relatively soft, compliant aluminum bearing particulate regions dispersed in a ceramic matrix. 3 figs.

  1. Brazing of sheet composite materials with aluminium matrix

    NASA Astrophysics Data System (ADS)

    Khorunov, V. F.; Kuchuk-Iatsenko, V. S.; Dykhno, I. S.; Kasatkina, N. V.

    The technique of brazing composite sheets with an aluminum matrix is investigated for Al matrices with either stainless steel or boron fibers. Brazing is compared to other joining techniques, and the relationship between heating and pressure levels is studied by characterizing the joint qualities microscopically. Solder composition is similarly analyzed, and brazing recommendations are given for ranges of joint sizes. Calculations of the temperature fields for the brazing of these composite materials yield specific-heat input data. Optimal brazing modes thus derived for the Al-matrix composites yield joints free of the intermetallide phases that degrade the performance of brazed structures. The tensile strength of the optimized joints is shown to be good relative to the strength of the original composites with Al matrices.

  2. Active joints for microrobot limbs

    Microsoft Academic Search

    M. Elwenspoek; L. Smith; B. Hok

    1992-01-01

    In this contribution we propose an electrostatic actuator for active joints. The active joint consists of two plates, one of which is a bilayer and bent by the bimorph effect. The plates are clamped to each other at one edge. A voltage between the plates leads to a very large field at the clamp where the plates are in intimate

  3. Robotic joint experiments under ultravacuum

    NASA Technical Reports Server (NTRS)

    Borrien, A.; Petitjean, L.

    1988-01-01

    First, various aspects of a robotic joint development program, including gearbox technology, electromechanical components, lubrication, and test results, are discussed. Secondly, a test prototype of the joint allowing simulation of robotic arm dynamic effects is presented. This prototype is tested under vacuum with different types of motors and sensors to characterize the functional parameters: angular position error, mechanical backlash, gearbox efficiency, and lifetime.

  4. International Joint Commission

    NSDL National Science Digital Library

    The International Joint Commission was created by Canada and the United States "because they recognized that each country is affected by the other's actions in lake and river systems along the border. The two countries cooperate to manage these waters wisely and to protect them for the benefit of today's citizens and future generations." Visitors to the site can read about great lakes water quality issues, great lakes exports, water levels, news releases, publications, view maps, and much more. One of the latest publications available on the site includes the proceeding from a workshop entitled Addressing Atmospheric Mercury: Science and Policy. This extensive site is well organized and written, giving anyone living near or interested in the great lakes a good source for timely and important information.

  5. Smart material joint band

    NASA Astrophysics Data System (ADS)

    Tucchio, Michael A.; Stoodt, Robert A.; Livsey, Robert A.

    1993-12-01

    The present invention relates to an improved connector for joining two tubular members together. The connector is formed by a plurality of longitudinally extending fingers extending from an end of one of the tubular members and at least one locking groove in the other of the tubular members for receiving the fingers. The connector further includes a circumferentially extending wire member which is received in a notch in a head portion of each of the plurality of fingers. The wire member is preferably formed from a shape memory alloy and has an original circumference less than the circumference of a circle formed by the notches in the head portions of the fingers. The connector includes apertures through which electric wires may be connected to the shape memory alloy ring member so as to cause the shape memory alloy ring member to return to its original shape and allow release of the joint connection.

  6. Smart material joint band

    NASA Astrophysics Data System (ADS)

    Tucchio, Michael A.; Stoodt, Robert A.; Livsey, Robert A.

    1994-11-01

    The present invention relates to an improved connector for joining two tubular members together. The connector is formed by a plurality of longitudinally extending fingers extending from an end of one of tubular members and at least one locking groove in the other of the tubular members for receiving the fingers. The connector further includes a circumferentially extending wire member which is received in a notch in a head portion of each of the plurality of fingers. The wire member is preferably formed from a shape memory alloy and has an original circumference less than the circumference of a circle formed by the notches in a head portions of the fingers. The connector includes apertures through which electric wires may be connected to the shape memory alloy ring member so as to cause the shape memory alloy ring member to return to its original shape and allow release of the joint connection.

  7. McNU'97 Symposium on Mechanics of Composites

    E-print Network

    Masud, Arif

    shells, postbuckling of composite shells, impact-induced damage and delamination, ortho- tropicPreface McNU'97 Symposium on Mechanics of Composites This issue of the journal consists of a selected list of papers presented at the Symposium on Mechanics of Composites of the McNU'97 Joint ASME

  8. Arthritis at the shoulder joint.

    PubMed

    Sankaye, Prashant; Ostlere, Simon

    2015-07-01

    The shoulder is a complex joint with numerous structures contributing to mobility and stability. Shoulder pain is a common clinical complaint that may be due to a wide spectrum of disorders including rotator cuff disease, instability, and arthropathy. Primary osteoarthritis of the shoulder joint is uncommon because it is a non-weight-bearing joint. Significant osteoarthritis of the glenohumeral joint is unusual in the absence of trauma, and the detection of advanced degenerative changes in patients without a known history of trauma should alert the clinician to search for other disorders. This article reviews the pathogenesis, clinical manifestations, and key imaging findings of the common categories of the arthritis affecting the glenohumeral joint. PMID:26021591

  9. 12 CFR 347.107 - Joint ventures.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 2010-01-01 false Joint ventures. 347.107 Section 347.107...REGULATIONS AND STATEMENTS OF GENERAL POLICY INTERNATIONAL BANKING § 347.107 Joint ventures. (a) Joint ventures. If a bank, directly or...

  10. 29 CFR 791.2 - Joint employment.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Joint employment. 791.2 Section 791...INTERPRETATION NOT DIRECTLY RELATED TO REGULATIONS JOINT EMPLOYMENT RELATIONSHIP UNDER FAIR LABOR STANDARDS ACT OF 1938 § 791.2 Joint employment. (a) A single...

  11. 29 CFR 791.2 - Joint employment.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Joint employment. 791.2 Section 791...INTERPRETATION NOT DIRECTLY RELATED TO REGULATIONS JOINT EMPLOYMENT RELATIONSHIP UNDER FAIR LABOR STANDARDS ACT OF 1938 § 791.2 Joint employment. (a) A single...

  12. 29 CFR 791.2 - Joint employment.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Joint employment. 791.2 Section 791...INTERPRETATION NOT DIRECTLY RELATED TO REGULATIONS JOINT EMPLOYMENT RELATIONSHIP UNDER FAIR LABOR STANDARDS ACT OF 1938 § 791.2 Joint employment. (a) A single...

  13. Study on microstructure and mechanical properties of 304 stainless steel joints by TIG, laser and laser TIG hybrid welding

    Microsoft Academic Search

    Jun Yan; Ming Gao; Xiaoyan Zeng

    2010-01-01

    This paper investigated the microstructure and mechanical properties of 304 stainless steel joints by tungsten inert gas (TIG) welding, laser welding and laser-TIG hybrid welding. The X-ray diffraction was used to analyze the phase composition, while the microscopy was conducted to study the microstructure characters of joints. Finally, tensile tests were performed and the fracture surfaces were analyzed. The results

  14. Development of cryogenic rotatable heat transfer joints

    NASA Astrophysics Data System (ADS)

    Sadunas, J. A.; Backovsky, Z. F.; Wilson, D. E.

    1992-07-01

    A summary of cryogenic rotatable heat transfer joint technology development, at Rockwell International Space Division, is presented. Starting with the flight qualified radiative joint on the RM-20B IR sensor of the early 70's, leading to rotatable heat pipe joint, gas conductive joints, rolling-contact-conductance joints, and the more recent work on development and evaluation of cryogenic rotatable seals and mechanical interfaces. Potential applications, joint design optimization, heat transfer, seal leakage and torque test data are presented.

  15. Joining of polypropylene\\/polypropylene and glass fiber reinforced polypropylene composites

    Microsoft Academic Search

    Jianguang Zhang

    2005-01-01

    Joining behavior of polypropylene (PP) to PP and long glass fiber reinforced polypropylene (LFT) to LFT were investigated. Adhesive bonding was used to join PP\\/PP. Both adhesive bonding and ultrasonic welding were used to join LFT\\/LFT. Single-lap shear testing and low velocity impact (LVI) testing were used to evaluate the performance of bonded structures. The two-part acrylic adhesive DP8005 was

  16. Failure mode and ageing of steel/epoxy joints

    NASA Astrophysics Data System (ADS)

    De'Nève, B.; Delamar, M.; Nguyen, T. T.; Shanahan, M. E. R.

    1998-09-01

    Torsional adhesive joints were made using a filled DGEBA based epoxy resin cured with dicyandiamide (DDA). Ageing, both of the joints and the bulk adhesive, was effected at 40, 55 and 70°C at ca. 98% relative humidity. Joint strength was monitored after various ageing periods. Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS) were used to analyze the adhesive and joint fracture surfaces. It was found that the adhesive composition near the adherent (zinc-electrocoated and bare steel) was modified compared with the bulk material. Before ageing there appeared to be an enrichment in hardener (DDA) near the adherent/adhesive interface and apparently adhesive failures were indeed interfacial. During ageing, the formation of ester groups subsequently transformed into carboxylates was observed. After ageing for up to 11?000 h, joints using a zinc electrocoated steel adherent showed fracture near the interface brought about by the modification of the adhesive. For longer ageing periods, failure occurred in a corrosion layer mixed with adhesive. A slightly better performance observed with the zinc electrocoated adherents has been attributed to the migration of Zn or Zn species into the adhesive during ageing.

  17. Structure and properties of welded joints from various titanium alloys

    Microsoft Academic Search

    A. A. Popov; A. G. Illarionov; M. A. Khorev; N. A. Drozdova

    1992-01-01

    Metallographic, x-ray diffraction, x-ray microspectral and hardness testing techniques have been used to examine the changes in the structure, phase composition, microhardness and the distribution of alloying elements in the parent metal and in the heat affected zone and in the seams of welded joints formed from various titanium alloys (VT6-OT4, VT6-VT20, VT23-OT4, VT23-VT6, VT23-VT19 and VT23-VT32) in the post

  18. Joint numerical ranges, quantum maps, and joint numerical shadows

    E-print Network

    Eugene Gutkin; Karol Zyczkowski

    2012-10-12

    We associate with k hermitian N\\times N matrices a probability measure on R^k. It is supported on the joint numerical range of the k-tuple of matrices. We call this measure the joint numerical shadow of these matrices. Let k=2. A pair of hermitian N\\times N matrices defines a complex N\\times N matrix. The joint numerical range and the joint numerical shadow of the pair of hermitian matrices coincide with the numerical range and the numerical shadow, respectively, of this complex matrix. We study relationships between the dynamics of quantum maps on the set of quantum states, on one hand, and the numerical ranges, on the other hand. In particular, we show that under the identity resolution assumption on Kraus operators defining the quantum map, the dynamics shrinks numerical ranges.

  19. Models for jointed rock structures

    NASA Astrophysics Data System (ADS)

    Heuze, F. E.; Barbour, T. G.

    1981-03-01

    Models for axisymmetric interfaces found in shaft and footing designs, and for the dilatant effects of rock joints, as encountered in underground caverns and reinforced rock slopes are presented. The models were incorporated into a finite element program, and test case analyses were performed. Use of the models can lead to safer estimates of footing settlements and shaft lining stresses, as well as to more economical design of rock reinforcement. Because the dilatant joint provides a refined estimate of joint opening and closing, it can be applied to the analysis of hard rock hydraulics, in which the flow is very sensitive to fracture aperture.

  20. Damage detection in composites by ZnO sensors

    Microsoft Academic Search

    H. J. Viljoen; N. F. J. van Rensburg

    1996-01-01

    The development of composites with self-diagnostic capabilities is based on the analysis of a mathematical model of the structure. The method is illustrated for a vibrating cantilevered plate and analyzed considering damping. Damage is modeled as an elastic joint, and the spectrum of natural frequencies is calculated for different positions and magnitudes of the elastic joint. Small sensors consisting of

  1. Arthritis: joints inflamed.

    PubMed

    Casey, Georgina

    2015-06-01

    ARTHRITIS IS a generic term for inflammatory joint disease. There are various forms of arthritis, including osteoarthritis, rheumatoid arthritis and spondyloarthritis. Arthritis can be a chronic debilitating condition or a transient effect of bacterial or viral infections. As a chronic condition, arthritis can cause loss of quality of life, disability and, with rheumatoid disease, early death. The economic burden of arthritis, in terms of management and loss of productivity due to disability, is high and set to increase with the ageing population. Recent advances in our understanding of the causes and progression of a number of forms of arthritis have raised hopes of better management and possible remission. Pharmacotherapy has moved from symptom management to addressing underlying disease processes. However, therapies that prevent or cure arthritis remain elusive. Current care for people with arthritis relies on a multidisciplinary approach and substantial pharmacological intervention. Nurses have a key role to play in guiding patients through treatment, ensuring they receive optimal therapy to reduce the impact of arthritis and its management on their lives. PMID:26168559

  2. Acromioclavicular joint cyst formation.

    PubMed

    Hiller, Andrew D; Miller, Joshua D; Zeller, John L

    2010-03-01

    Acromioclavicular joint (ACJ) cysts are an uncommon and unusual sequela associated with shoulder pathophysiology. The majority of literature on ACJ cysts consists of individual case reports with no definitive literature review currently available. In addition to a comprehensive literature review, four clinical cases are presented in this report. First described by Craig (1984), a total of 41 cases have been previously reported in the literature. Of these cases, five occurred with the rotator cuff musculature intact. The remaining 36 cases of ACJ cysts occurred in patients with a complete tear/avulsion of the rotator cuff. Previous attempts at compiling a complete record of all reported cases have combined several distinct conditions into a single category. This article presents two distinct etiologies for the pathogenesis of ACJ cyst formation. In the presence of an intact rotator cuff, a Type 1 cyst can form superficially and be limited to the ACJ. Following a massive or traumatic tear of the rotator cuff, mechanical instability of the humeral head can cause a deterioration of the inferior acromioclavicular capsule (cuff tear arthropathy) and an overproduction of synovial fluid. Overtime, a "geyser" of fluid can form between the glenohumeral and the ACJ, forming a Type 2 cyst. This differentiation and categorization is essential for appropriate classification and treatment. PMID:20069645

  3. Joint services electronics program

    NASA Astrophysics Data System (ADS)

    Peters, Leon, Jr.

    1992-11-01

    The report represents the fifteenth annual summary of The Ohio State University Joint Services Electronics Program (JSEP). The transfer of the compact range identification technology initiated under JSEP support for time domain studies continues to make large advances. We are also assisting Rockwell (Tulsa) to update their RCS facilities. This work is on a subcontract to the ESL from the Air Force. This has lead to involvement in the study of Ultra Wide Band radar systems. The research activities devoted to the Generalized Ray and Gaussian Beams continues. Our JSEP research continues to be expanded by external funding. This program is being expanded by use of such funds which are more focussed on the requirements of the sponsors which includes both the Air Force and the Navy. Our JSEP research continues to focus on electromagnetic related topics. There are four major electromagnetics areas that were pursued in the past year. The Diffraction Studies Work Unit has initiated research on a time domain version of the Uniform Theory of Diffraction. A second topic under the Diffraction Studies Work Unit involves further extensions of the generalized resistive boundary condition and the generalized impedance boundary condition. These have been applied to scattering from a chiral slab. A third topic of interest is the diffraction from a corner. A fourth task involves the reflection/diffraction of a Gaussian beam. This represents an approach to replace the usual ray optics solution for very complex geometries where the versatile ray optics solution becomes cumbersome.

  4. Retort braze bonding of borsic/aluminum composite sheet to titanium

    NASA Technical Reports Server (NTRS)

    Webb, B. A.; Dolowy, J. F., Jr.

    1975-01-01

    Braze bonding studies between Borsic/aluminum composite and titanium sheet were conducted to establish acceptable brazing techniques and to assess potential joint efficiencies. Excellent braze joints were produced which exhibited joint strengths exceeding 117 MPa (17,000 psi) and which retained up to 2/3 of this strength at 589 K (600 F). Noticeable composite strength degradation resulting from the required high temperature braze cycle was found to be a problem.

  5. Osteochondral Lesions of Major Joints

    PubMed Central

    Durur-Subasi, Irmak; Durur-Karakaya, Afak; Yildirim, Omer Selim

    2015-01-01

    This paper provides information about osteochondral lesions (OCL) and example cases of OCL occurring in major joints, some of which are rarely seen. This simple tutorial is presented in question and answer format. PMID:26180500

  6. MISR JOINT_AS Data

    Atmospheric Science Data Center

    2014-07-21

    ... reported on various geographic grids depending on the data product. Parameters from multiple orbits are combined to make complete ... The Joint Aerosol product provides a monthly global statistical summary of MISR Level 2 aerosol optical depth retrievals on a 5 ...

  7. The complexity of joint computation

    E-print Network

    Drucker, Andrew Donald

    2012-01-01

    Joint computation is the ubiquitous scenario in which a computer is presented with not one, but many computational tasks to perform. A fundamental question arises: when can we cleverly combine computations, to perform them ...

  8. Father by law: Effects of joint legal custody on nonresident fathers’ involvement with children

    Microsoft Academic Search

    Judith A. Seltzer

    1998-01-01

    Family membership and household composition do not always coincide. Joint legal custody after divorce formalizes the relationship\\u000a between fathers and children who live apart. Policymakers hope that explicit acknowledgment of nonresident fathers’ rights\\u000a and responsibilities will increase their involvement with their children. I use prospective data from the National Survey\\u000a of Families and Households to examine the association between joint

  9. Fatigue strength improvement of MIG-welded joint by shot peening

    Microsoft Academic Search

    Nur Azida Che Lah; Aidy Ali

    2011-01-01

    In this study, the effect of controlled shot peening (CSP) treatment on the fatigue strength of an ASTM A516 grade 70 carbon steel MIG-welded joint has been studied quantitatively. Metallurgical modifications, hardness, elemental compositions, and internal discontinuities, such as porosity and inclusions found in treated and untreated fusion welded joints, were characterized. The fatigue results of as-welded and peened skimmed

  10. Joint probabilities and quantum cognition

    NASA Astrophysics Data System (ADS)

    de Barros, J. Acacio

    2012-12-01

    In this paper we discuss the existence of joint probability distributions for quantumlike response computations in the brain. We do so by focusing on a contextual neural-oscillator model shown to reproduce the main features of behavioral stimulus-response theory. We then exhibit a simple example of contextual random variables not having a joint probability distribution, and describe how such variables can be obtained from neural oscillators, but not from a quantum observable algebra.

  11. Joint probabilities and quantum cognition

    SciTech Connect

    Acacio de Barros, J. [Liberal Studies, 1600 Holloway Ave., San Francisco State University, San Francisco, CA 94132 (United States)

    2012-12-18

    In this paper we discuss the existence of joint probability distributions for quantumlike response computations in the brain. We do so by focusing on a contextual neural-oscillator model shown to reproduce the main features of behavioral stimulus-response theory. We then exhibit a simple example of contextual random variables not having a joint probability distribution, and describe how such variables can be obtained from neural oscillators, but not from a quantum observable algebra.

  12. Blood-Induced Joint Damage

    PubMed Central

    Roosendaal, Goris; Jansen, Nathalie W.D.; Lafeber, Floris P.J.G.; Mastbergen, Simon C.

    2013-01-01

    Objective: Four days of blood exposure leads to irreversible cartilage damage in vitro. In contrast, intermittent intra-articular blood injections twice a week during 4 weeks (mimicking micro-bleeds) in a canine model resulted in transient damage only. In this study, it was evaluated whether acute joint bleeds are more harmful than micro-bleeds in a canine model of knee arthropathy. Design: Seven dogs received 4 sequential daily intra-articular blood injections twice in 2 weeks (mimicking 2 acute 4-day joint bleeds). Seven other dogs received the same blood load but in a total of 8 injections intermittently over the 4-week period with at least 1 day in between (mimicking micro-bleeds over the same timespan). Contralateral knees served as controls. Ten weeks after the last injection cartilage matrix turnover and synovial inflammation were evaluated. Results: Only after the acute joint bleeds the release of newly formed and total (resident) cartilage matrix glycosaminoglycans were increased (P = 0.04 and P = 0.01, respectively). Furthermore, in animals with the acute joint bleeds cartilage glycosaminoglycan content was decreased (P = 0.01) and not in animals with micro-bleeds. Mild synovial inflammation was observed in both groups (both P < 0.0001) but was not different between groups. Conclusions: In contrast to micro-bleeds, 2 acute joint bleeds lead to prolonged cartilage damage independent of the level of synovial inflammation. This model suggests that micro-bleeds are less devastating than acute joint bleeds with respect to joint damage, which might be of relevance to treatment of joint bleeds in clinical practice.

  13. Joint probabilities and quantum cognition

    E-print Network

    de Barros, J Acacio

    2012-01-01

    In this paper we discuss the existence of joint probability distributions for quantum-like response computations in the brain. We do so by focusing on a contextual neural-oscillator model shown to reproduce the main features of behavioral stimulus-response theory. We then exhibit a simple example of contextual random variables not having a joint probability distribution, and describe how such variables can be obtained from neural oscillators, but not from a quantum observable algebra.

  14. 5, 163185, 2008 Joint effect of the

    E-print Network

    Paris-Sud XI, Université de

    investigated. Joint effect of the WPWP and EPWP on ENSO was examined based on a joint effect index, which by the WPWP and EPWP on ENSO, and the joint effect of both warm pools must be considered. A joint index of 1 global climate abnormity and serious drought or flood, and cold calamity in many regions of the world

  15. Acromioclavicular joint reconstruction: complications and innovations.

    PubMed

    Brand, Jefferson C; Lubowitz, James H; Provencher, Matthew T; Rossi, Michael J

    2015-05-01

    Minimally invasive anatomic reconstruction of the acromioclavicular joint is a technically challenging procedure. The repair must be sufficiently strong and reconstitute the joint as closely as possible. This includes restoration of both superior-inferior stability, and the often overlooked anterior-posterior stability, of the acromioclavicular joint. There is no gold standard treatment for acromioclavicular joint separation. PMID:25953219

  16. Degenerative joint disease in captive waterfowl

    Microsoft Academic Search

    L. A. Degernes; P. S. Lynch; H. L. Shivaprasad

    2011-01-01

    A retrospective study was conducted to evaluate degenerative joint disease (DJD) in captive waterfowl that died or were euthanized at Fresno's Chaffee Zoo in Fresno, California, USA from 2001 to 2005. Of these, 16 out of 33 birds (48%) had DJD in one or both stifle (femoral–tibiotarsal joint; n = 13), hock (tibiotarsal–tarsometatarsal joint; n = 4), or toe joints

  17. Young Children's Understanding of Joint Commitments

    ERIC Educational Resources Information Center

    Grafenhain, Maria; Behne, Tanya; Carpenter, Malinda; Tomasello, Michael

    2009-01-01

    When adults make a joint commitment to act together, they feel an obligation to their partner. In 2 studies, the authors investigated whether young children also understand joint commitments to act together. In the first study, when an adult orchestrated with the child a joint commitment to play a game together and then broke off from their joint

  18. 7 CFR 97.14 - Joint applicants.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...Agriculture 3 2012-01-01 2012-01-01 false Joint applicants. 97.14 Section 97.14 Agriculture...VARIETY AND PROTECTION The Application § 97.14 Joint applicants. (a) Joint owners shall file a joint application by...

  19. Joint Press Release TWELFTH ITER NEGOTIATION MEETING

    E-print Network

    Joint Press Release TWELFTH ITER NEGOTIATION MEETING Jeju, Korea, 6 December th 2005 Delegations on an Agreement on the joint implementation of the ITER international fusion energy project. This was the first/6/05 1:21 PMDraft Joint News Release Page 1 of 2http://www.iter.org/N_12_Joint_Press_Release.htm #12

  20. 7 CFR 97.14 - Joint applicants.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...Agriculture 3 2014-01-01 2014-01-01 false Joint applicants. 97.14 Section 97.14 Agriculture...VARIETY AND PROTECTION The Application § 97.14 Joint applicants. (a) Joint owners shall file a joint application by...

  1. 7 CFR 97.14 - Joint applicants.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...Agriculture 3 2011-01-01 2011-01-01 false Joint applicants. 97.14 Section 97.14 Agriculture...VARIETY AND PROTECTION The Application § 97.14 Joint applicants. (a) Joint owners shall file a joint application by...

  2. 7 CFR 97.14 - Joint applicants.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...Agriculture 3 2013-01-01 2013-01-01 false Joint applicants. 97.14 Section 97.14 Agriculture...VARIETY AND PROTECTION The Application § 97.14 Joint applicants. (a) Joint owners shall file a joint application by...

  3. The interplay of microstructure, geometry, and stress state on the mechanical performance of MMC joints

    NASA Astrophysics Data System (ADS)

    Brink, Damon Douglas

    Model MMC joints were fabricated to provide an avenue for assessing the failure mechanisms which limit the performance of composite joints. The joints consisted of aluminum matrix composite subelements separated by thin metal interlayers, and were manufactured by pressure infiltration of an Al-4.5% Mg alloy into preforms of polycrystalline alumina fibers containing planar discontinuities. This technique minimized processing defects and ensured interface integrity. The high degree of constraint and concurrent buildup of large hydrostatic stresses in the metal interlayers allowed simple butt joints to support applied loads in excess of two times the metal yield strength. The composite-interlayer interface fails at these stress levels due to the nucleation, growth, and coalescence of voids at the fiber ends. The performance of joints with interlayers inclined at various scarf angles was investigated and revealed that the applied load at failure increased substantially when the interlayers were inclined at angles greater than 45°. The strain to failure also increases significantly under these conditions, although strength remains limited by the load carrying capacity of the composite-interlayer interface. The change in performance is due to the dependence of the interlayer stress state on scarf angle, an effect modeled with both analytical and finite element techniques. Microstructural changes associated with varying scarf angles are also discussed. The addition of particulate reinforcement to the interlayers provides an alternative manner in which to change the interlayer stress state. Model butt joints with reinforced interlayers exhibited strength increases of up to 50% over unreinforced joints. More importantly, joint strength was not limited by failure along the composite-interlayer interface when particles were present. Failure instead occurred through the reinforced interlayer, often at substantially higher loads. The change in failure mode is associated with changes in the interlayer stress state on two length scales, as has been demonstrated with finite element calculations of the entire joint and individual fiber ends. A macroscopic description of the interface stress state was found to correlate with fracture in all the model joint specimens tested. The criterion is based on work by Rice and Tracey [69RiT], and accounts for the growth and coalescence of voids under different combinations of hydrostatic stress and plastic strain. In addition, stresses normal to individual fiber ends were found to be consistent between joints with varying scarf angles when this criterion was satisfied.

  4. Fatigue strength improvement of MIG-welded joint by shot peening

    NASA Astrophysics Data System (ADS)

    Azida Che Lah, Nur; Ali, Aidy

    2011-02-01

    In this study, the effect of controlled shot peening (CSP) treatment on the fatigue strength of an ASTM A516 grade 70 carbon steel MIG-welded joint has been studied quantitatively. Metallurgical modifications, hardness, elemental compositions, and internal discontinuities, such as porosity and inclusions found in treated and untreated fusion welded joints, were characterized. The fatigue results of as-welded and peened skimmed joints were compared. It was observed that the effect of the CSP and skimming processes improved the fatigue life of the fusion weld by 63% on MIG-welded samples.

  5. How joint is the joint attention of apes and human infants? Malinda Carpenter

    E-print Network

    Carpenter, M.alinda

    How joint is the joint attention of apes and human infants? Malinda Carpenter Josep Call Department In press, Agency and joint attention, H.S. Terrace & J. Metcalfe (Eds.). New York: Oxford University Press. #12;The jointness of joint attention 2 Abstract In this chapter we first argue (following Tomasello

  6. Ceramic vane drive joint

    DOEpatents

    Smale, Charles H. (Indianapolis, IN)

    1981-01-01

    A variable geometry gas turbine has an array of ceramic composition vanes positioned by an actuating ring coupled through a plurality of circumferentially spaced turbine vane levers to the outer end of a metallic vane drive shaft at each of the ceramic vanes. Each of the ceramic vanes has an end slot of bow tie configuration including flared end segments and a center slot therebetween. Each of the vane drive shafts has a cross head with ends thereof spaced with respect to the sides of the end slot to define clearance for free expansion of the cross head with respect to the vane and the cross head being configured to uniformly distribute drive loads across bearing surfaces of the vane slot.

  7. An analysis of a joint shear model for jointed media with orthogonal joint sets; Yucca Mountain Site Characterization Project

    SciTech Connect

    Koteras, J.R.

    1991-10-01

    This report describes a joint shear model used in conjunction with a computational model for jointed media with orthogonal joint sets. The joint shear model allows nonlinear behavior for both joint sets. Because nonlinear behavior is allowed for both joint sets, a great many cases must be considered to fully describe the joint shear behavior of the jointed medium. An extensive set of equations is required to describe the joint shear stress and slip displacements that can occur for all the various cases. This report examines possible methods for simplifying this set of equations so that the model can be implemented efficiently form a computational standpoint. The shear model must be examined carefully to obtain a computationally efficient implementation that does not lead to numerical problems. The application to fractures in rock is discussed. 5 refs., 4 figs.

  8. STS payloads mission control study continuation phase A-1. Volume 2-C, task 3: Identification of joint activities and estimation of resources in preparation for joint flight operations

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Payload mission control concepts are developed for real time flight operations of STS. Flight planning, training, simulations, and other flight preparations are included. Payload activities for the preflight phase, activity sequences and organizational allocations, and traffic and experience factors to establish composite man-loading for joint STS payload activities are identified for flight operations from 1980 to 1985.

  9. Unsharp measurements and joint measurability

    E-print Network

    H. S. Karthik; A. R. Usha Devi; A. K. Rajagopal

    2015-05-16

    We give an overview of joint unsharp measurements of non-commuting observables using positive operator valued measures (POVMs). We exemplify the role played by joint measurability of POVMs in entropic uncertainty relation for Alice's pair of non-commuting observables in the presence of Bob's entangled quantum memory. We show that Bob should record the outcomes of incompatible (non-jointly measurable) POVMs in his quantum memory so as to beat the entropic uncertainty bound. In other words, in addition to the presence of entangled Alice-Bob state, implementing incompatible POVMs at Bob's end is necessary to beat the uncertainty bound and hence, predict the outcomes of non-commuting observables with improved precision. We also explore the implications of joint measurability to {\\em validate} a moment matrix constructed from average pairwise correlations of three dichotomic non-commuting qubit observables. We prove that a classically acceptable moment matrix -- which ascertains the existence of a legitimate joint probability distribution for the outcomes of all the three dichotomic observables -- could be realized if and only if compatible POVMs are employed.

  10. Strength of welded copper joints

    SciTech Connect

    Kuzyukova, A.N.; Fedorenko, M.I.; Kovalenko, N.I.; Zelik, E.I.

    1983-07-01

    A coefficient of the strength of welded joints in structures of copper and its alloys made by manual arc welding are known. At the Severedonetsk Branch of the Institute of Chemical Engineering the strength coefficients were determined for welded joints made of MZR (phosphorous-deoxydized) copper produced by manual argonarc welding. Optimum welding regimes were selected, and specimens of strips tested for tensile strength. Metallographic investigations showed significant grain growth in the zone of thermal influence. The results of mechanical tests are given. The results are verified by the fabrication of nine models. All the models ruptured in the zone of thermal influence, confirming results that the zone of thermal influence was the weak point in the welded joints in copper.

  11. A review of ceramic bearing materials in total joint arthroplasty.

    PubMed

    Bal, B S; Garino, J; Ries, M; Rahaman, M N

    2007-01-01

    Bearings made of ceramics have ultra-low wear properties that make them suitable for total hip arthroplasty (THA) and total knee arthroplasty (TKA). When compared to cobalt chrome (CoCr)-on-polyethylene (PE) articulations, ceramics offer drastic reductions in bearing wear rates. Lower wear rates result in fewer wear particles produced by the articulating surfaces. In theory, this should reduce the risk of periprosthetic osteolysis and premature implant loosening, thereby contributing to the longevity of total joints. In addition to ceramics, other alternative bearing couples, such as highly cross-linked PE (XLPE) and metal-on-metal also offer less wear than CoCr-on-PE articulations in total joint arthroplasty. Alumina and zirconia ceramics are familiar to orthopaedic surgeons since both materials have been used in total joints for several decades. While not new in Europe, alumina-on-alumina ceramic total hips have only recently become available for widespread use in the United States from various orthopaedic implant manufacturers. As the search for the ideal total joint bearing material continues, composite materials of existing ceramics, metal-on-ceramic articulations, and new ceramic technologies will offer more choices to the arthroplasty surgeon. The objective of this paper is to present an overview of material properties, clinical applications, evolution, and limitations of ceramic materials that are of interest to the arthroplasty surgeon. PMID:19197839

  12. Composite Load Model Evaluation

    SciTech Connect

    Lu, Ning; Qiao, Hong (Amy)

    2007-09-30

    The WECC load modeling task force has dedicated its effort in the past few years to develop a composite load model that can represent behaviors of different end-user components. The modeling structure of the composite load model is recommended by the WECC load modeling task force. GE Energy has implemented this composite load model with a new function CMPLDW in its power system simulation software package, PSLF. For the last several years, Bonneville Power Administration (BPA) has taken the lead and collaborated with GE Energy to develop the new composite load model. Pacific Northwest National Laboratory (PNNL) and BPA joint force and conducted the evaluation of the CMPLDW and test its parameter settings to make sure that: • the model initializes properly, • all the parameter settings are functioning, and • the simulation results are as expected. The PNNL effort focused on testing the CMPLDW in a 4-bus system. An exhaustive testing on each parameter setting has been performed to guarantee each setting works. This report is a summary of the PNNL testing results and conclusions.

  13. Joint service EOD robotics program

    NASA Astrophysics Data System (ADS)

    Hacker, Kurt; Brezina, Byron; DeBolt, Chris

    2006-05-01

    Within the military, the Explosive Ordnance Disposal (EOD) community has been an early adopter of robotic capabilities. The Joint Service EOD (JSEOD) Program is in the process of fielding its third generation of robotic systems to the EOD technicians. Robots have been an invaluable asset to the EOD technician, and they have been critical to operations in Iraq as we prosecute the IED problem. This paper provides a brief history of past EOD robotic systems, a description of currently fielded and supported systems, and the future of robotic programs within the Joint Service EOD community.

  14. [Divorce and joint physical custody].

    PubMed

    Golse, B

    2014-04-01

    This work first recalls the definition of joint physical custody, as well as the current legal procedure for obtaining it, its practical implementation, the financial implications for parents, and finally some statistics. Some psychological and psychopathological reflections on the impact of divorce on children are then presented before considering the question of joint physically custody with regard to attachment theory and depending on the age of the child (a great caution seems to be required before three years). The article concludes with a brief discussion of parental alienation syndrome. PMID:24630624

  15. Torque Limits for Fasteners in Composites

    NASA Technical Reports Server (NTRS)

    Zhao, Yi

    2002-01-01

    The two major classes of laminate joints are bonded and bolted. Often the two classes are combined as bonded-bolted joints. Several characteristics of fiber reinforced composite materials render them more susceptible to joint problems than conventional metals. These characteristics include weakness in in-plane shear, transverse tension/compression, interlaminar shear, and bearing strength relative to the strength and stiffness in the fiber direction. Studies on bolted joints of composite materials have been focused on joining assembly subject to in-plane loads. Modes of failure under these loading conditions are net-tension failure, cleavage tension failure, shear-out failure, bearing failure, etc. Although the studies of torque load can be found in literature, they mainly discussed the effect of the torque load on in-plane strength. Existing methods for calculating torque limit for a mechanical fastener do not consider connecting members. The concern that a composite member could be crushed by a preload inspired the initiation of this study. The purpose is to develop a fundamental knowledge base on how to determine a torque limit when a composite member is taken into account. Two simplified analytical models were used: a stress failure analysis model based on maximum stress criterion, and a strain failure analysis model based on maximum strain criterion.

  16. Plastic working of laminated composite materials

    Microsoft Academic Search

    S. V. Voronov; D. G. Devoino

    1982-01-01

    Plastic working can be successfully employed for increasing the strength of the joint in a laminated composite material whose components react with each other during high-speed cladding, with the formation of brittle intermetallic compouds. At the same time, by suitable choice of reduction and mismatch, it is possible to produce straight bimetallic strips by rolling them with mismatched peripheral roll

  17. Joint service EOD robotics program

    Microsoft Academic Search

    Kurt Hacker; Byron Brezina; Chris DeBolt

    2006-01-01

    Within the military, the Explosive Ordnance Disposal (EOD) community has been an early adopter of robotic capabilities. The Joint Service EOD (JSEOD) Program is in the process of fielding its third generation of robotic systems to the EOD technicians. Robots have been an invaluable asset to the EOD technician, and they have been critical to operations in Iraq as we

  18. OBSERVATION DIRECT DES JOINTS INTERGRANULAIRES.

    E-print Network

    Boyer, Edmond

    OF INTERFACES D. A. SMITH Department of Metallurgy, University of Oxford, Parks Road, Oxford, England. RCsum6 interfaciales conservent I'ordre dans les joints et leurs propriCtCs peuvent contrbler les processus qui se transmission electron microscopy. Interfacial dislocations conserve the order at boundaries and their behaviour

  19. [Metabolic bone and joint diseases].

    PubMed

    Endo, Itsuro

    2014-10-01

    Metabolic bone and joint diseases in adults include osteomalacia, rheumatoid arthritis, gouty arthritis. Recently, the newest molecular biology procedures and the clinical observation studies can produce good results for understanding of these diseases. From this perspective, the author introduced updated information of the pathophysiology, the latest diagnostic criteria and the therapy of these diseases. PMID:25509803

  20. Space station rotary joint mechanisms

    NASA Technical Reports Server (NTRS)

    Driskill, Glen W.

    1986-01-01

    The mechanism which will be used on the space station to position the solar arrays and radiator panels for Sun pointing and Sun avoidance is described. The unique design features will be demonstrated on advanced development models of two of the joints being fabricated under contract to NASA-MSFC.

  1. [Fetal bone and joint disorders].

    PubMed

    Jakobovits, Akos

    2008-12-21

    The article discusses the physiology and pathology of fetal bone and joint development and functions. The bones provide static support for the body. The skull and the bones of spinal column encase the central and part of the peripheral nervous system. The ribs and the sternum shield the heart and the lungs, while the bones of the pelvis protect the intraabdominal organs. Pathological changes of these bony structures may impair the functions of the respective systems or internal organs. Movements of the bones are brought about by muscles. The deriving motions are facilitated by joints. Bony anomalies of the extremities limit their effective functions. Apart from skeletal and joint abnormalities, akinesia may also be caused by neurological, muscular and skin diseases that secondarily affect the functions of bones and joints. Such pathological changes may lead to various degrees of physical disability and even to death. Some of the mentioned anomalies are recognizable in utero by ultrasound. The diagnosis may serve as medical indication for abortion in those instances when the identified abnormality is incompatible with independent life. PMID:19073454

  2. Offered jointly with International Business

    E-print Network

    Offered jointly with Master in International Business #12;.02 Welcome to Barcelona Welcome to UPF where business, culture and social life drive the community. Barcelona has one of the world's highest. Master in International Business #12;ESCI, Escola Superior de Comerç Internacional www.esci.upf.edu .03

  3. JD MADR Joint Degree Description

    E-print Network

    Berdichevsky, Victor

    ) are considered equivalent to two core MADR courses, DR 7220 (Neutral Intervention) and DR 7210 (Negotiation (Alternative Dispute Resolution) are equivalent, to the core MADR courses of DR 7210 (Negotiation), DR 7220. Sample Schedule For JD/MADR Joint Degree YEAR 1: Fall Semester Total Cr. JD Cr. MADR Cr. LEX 6100 - Civil

  4. Plating To Reinforce Welded Joints

    NASA Technical Reports Server (NTRS)

    Otousa, J. E.

    1982-01-01

    Electrodeposition used to strengthen welded joints gouged, nicked, or suffered other mechanical damage. Plating cell, typically of acrylic plastic such as poly (Methylmetacrylate), is assembled around part to be plated. Areas not to be plated are masked with plater's tape. Weld area is plated in standard nickel-plating process.

  5. Methods of jointing ceramic pipes

    Microsoft Academic Search

    I. I. Arkhipov; Z. O. Nemchenok

    1975-01-01

    In Czechoslovakia the ceramic pipes are jointed with the help of rubber sealing rings. The rings have a reinforced core and two internal flaps. In the cuff of the ring a steel reinforcement is pressed which hinders its deformation during mounting. The ring has a conical shape and when installed in the neck of a pipe, it clamps by itself.

  6. The Joint Gravity Model 3

    Microsoft Academic Search

    B. D. Tapley; M. M. Watkins; J. C. Ries; G. W. Davis; R. J. Eanes; S. R. Poole; H. J. Rim; B. E. Schutz; C. K. Shum; R. S. Nerem; F. J. Lerch; J. A. Marshall; S. M. Klosko; N. K. Pavlis; R. G. Williamson

    1996-01-01

    An improved Earth geopotential model, complete to spherical harmonic degree and order 70, has been determined by combining the Joint Gravity Model 1 (JGM 1) geopotential coefficients, and their associated error covariance, with new information from SLR, DORIS, and GPS tracking of TOPEX\\/Poseidon, laser tracking of LAGEOS 1, LAGEOS 2, and Stella, and additional DORIS tracking of SPOT 2. The

  7. Chicken Skeleton - Gliding Joint (Skull)

    NSDL National Science Digital Library

    Ketan Patel (California State University, Fullerton; Student, Biological Sciences)

    2007-07-28

    The chicken uses its beak to pick up small pieces of food from the ground. The gliding joint at the base of the skull allows the chicken to move its head in different directions. It can also defend itself by pecking.

  8. Sea Lion Skeleton (Gliding Joint)

    NSDL National Science Digital Library

    Ketan Patel (California State University, Fullerton; Student, B)

    2007-07-14

    Sea lions are vertebrates with both backbones and ribs. The backbone is a gliding joint, allowing the animal to be flexible, while the ribs main function is to protect it's inner organs. The short tail helps to balance the animal while walking on land.

  9. Joint measurements and Svetlichny's inequality

    E-print Network

    Yang Xiang; Wei Ren

    2010-12-27

    We prove that the Svetlichny's inequality can be derived from the existence of joint measurements and the principle of no-signaling. Then we show that, on the basis of quantum measurement assumption, it would imply the breach of causality if the magnitude of violation of Svetlichny's inequality exceeds quantum bound.

  10. Design Methodology for Scarf Repairs to Composite Structures

    Microsoft Academic Search

    C. H. Wang; A. Gunnion

    Scarf repairs are the preferred method of repairing thick composite structures, especially when externally bonded patches can no longer meet the stiffness, strength, and flushness requirements. Present designs of scarf repairs are based on two-dimensional analyses of scarf joints, assuming a uniform stress distribution along the scarf. This report presents an improve design methodology for designing scarf repairs to composite

  11. RESIDUAL STRESS EFFECTS IN FRACTURE OF COMPOSITES AND ADHESIVES

    E-print Network

    Nairn, John A.

    RESIDUAL STRESS EFFECTS IN FRACTURE OF COMPOSITES AND ADHESIVES JOHN A. NAIRN ABSTRACT Because, they inevitably develop residual thermal stresses. When designing composites or adhesive joints, it is important to account for these residual stresses. It is not the magnitude of the residual stresses that matters

  12. Dimensionally stable graphite-fiber-reinforced composite mirror technology

    Microsoft Academic Search

    James P. Gormican; Shel Kulick; Eldon P. Kasl; Laura B. Abplanalp

    1993-01-01

    Lightweight, high performance optical systems have historically relied upon ultralightweight optical components to achieve high stiffness, low weight, high quality optical surfaces exhibiting high thermal stability. Composite Optics, Incorporated (COI) has independently pursued state-of-the-art graphite fiber reinforce composite (GFRC) substrates for microwave and infrared (IR) applications. Eastman Kodak Company (Kodak) and COI have participated in a joint evaluation of hybrid

  13. Tests on riveted joints in sheet duralumin

    NASA Technical Reports Server (NTRS)

    Rettew, H F; Thumin, G

    1923-01-01

    In making tension tests, the slippage of the joints was noted at three points across each joint. In addition, stress strain curves were obtained for plain tension specimens, and a chemical analysis was made of the sheet.

  14. Joint Disorders - Multiple Languages: MedlinePlus

    MedlinePLUS

    ... ?????????? ?????? ??????? - ??????? Bilingual PDF Health Information Translations Bosnian (Bosanski) Home Care After Total Joint Replacement ... zamjene zgloba - Bosanski (Bosnian) Bilingual PDF Health Information Translations Chinese - Simplified (????) Home Care After Total Joint ...

  15. 30 CFR 36.24 - Engine joints.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...OF MINING PRODUCTS APPROVAL REQUIREMENTS FOR PERMISSIBLE MOBILE DIESEL-POWERED TRANSPORTATION EQUIPMENT Construction and Design Requirements § 36.24 Engine joints. (a) Cylinder head. The joint between the cylinder...

  16. 30 CFR 36.24 - Engine joints.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...OF MINING PRODUCTS APPROVAL REQUIREMENTS FOR PERMISSIBLE MOBILE DIESEL-POWERED TRANSPORTATION EQUIPMENT Construction and Design Requirements § 36.24 Engine joints. (a) Cylinder head. The joint between the cylinder...

  17. Shear-Joint Capability Versus Bolt Clearance

    NASA Technical Reports Server (NTRS)

    Lee, H. M.

    1994-01-01

    NASA Technical Memorandum presents theoretical study of relationships between load-bearing capabilities of shear joints that comprise plates clamped together by multiple bolts and clearances between bolts and boltholes in those joints.

  18. Joint Honours BA in Philosophy and Political Science 120 credits (4 years) 3 credits = 1 course Valid for the 20142015 academic year.

    E-print Network

    Sankoff, David

    Joint Honours BA in Philosophy and Political Science ­ 120 credits (4 years) 3 credits = 1 course Fiction ENG1121 Literature and Composition II: Drama and Poetry Firstprogram JointHonoursBAinPhilosophyandPoliticalScience to Political Science Recommended course1 : POL1102 Politics and Globalization PHI2170 Logic I PHI2174 Ethics

  19. Utilisation de la dpendance du comportement de l'adhsif vis--vis de la pression hydrostatique pour optimiser la capacit des joints colls

    E-print Network

    Paris-Sud XI, Université de

    joint courbe semble prometteur. Abstract Structural adhesive bonding is nowadays often used in the field techniques to realize new composite structures. Yet, structural adhesive bonding induces stress as shear stress optimisation for adhesively bonded joints. In this article, the role of the hydrostatic

  20. Graphite composite tape in beam-pumped oil wells

    SciTech Connect

    Hensley, H.N.; Tanner, C.J.

    1984-09-01

    A continuous, reelable graphite composite tape is being developed as an alternative to jointed sucker rods for use in beam pumped oil wells. Four units have been tested in wells. The composite tape is composed of graphite fibers, glass fabric, Kevlar fibers and vinylester resin. Graphite fibers have a high modulus of elasticity and provide the longitudinal stiffness needed to operate the downhole pump, while allowing a thin cross section flexible enough to be wound onto small diameter reels. This advanced graphite composite is the first practical, lightweight, reelable alternative to jointed sucker rods.

  1. Asphaltic compositions

    SciTech Connect

    Wright, W.E.; Zaweski, E.F.

    1987-02-24

    This patent describes an asphaltic composition of enhanced utility for vehicular pavement which composition comprises a road paving grade of asphalt in admixture with at least one alkylene dithiocarbamate. The composition is characterized by having a reduced increase in absolute viscosity to original absolute viscosity after thin film aging as measured by ASTM Test D 1754 at 140/sup 0/F.

  2. Re-Creation of Historical Chrysotile-Containing Joint Compounds

    PubMed Central

    Brorby, G. P.; Sheehan, P. J.; Berman, D. W.; Greene, J. F.; Holm, S. E.

    2008-01-01

    Chrysotile-containing joint compound was commonly used in construction of residential and commercial buildings through the mid 1970s; however, these products have not been manufactured in the United States for more than 30 years. Little is known about actual human exposures to chrysotile fibers that may have resulted from use of chrysotile-containing joint compounds, because few exposure and no health-effects studies have been conducted specifically with these products. Because limited amounts of historical joint compounds are available (and the stability or representativeness of aged products is suspect), it is currently impossible to conduct meaningful studies to better understand the nature and magnitude of potential exposures to chrysotile that may have been associated with historical use of these products. Therefore, to support specific exposure and toxicology research activities, two types of chrysotile-containing joint compounds were produced according to original formulations from the late 1960s. To the extent possible, ingredients were the same as those used originally, with many obtained from the original suppliers. The chrysotile used historically in these products was primarily Grade 7RF9 from the Philip Carey mine. Because this mine is closed, a suitable alternate was identified by comparing the sizes and mineral composition of asbestos structures in a sample of what has been represented to be historical joint compound (all of which were chrysotile) to those in samples of three currently commercially available Grade 7 chrysotile products. The re-created materials generally conformed to original product specifications (e.g. viscosity, workability, crack resistance), indicating that these materials are sufficiently representative of the original products to support research activities. PMID:18788019

  3. TECHNICAL NOTE: Observations on the use of a viscoelastic joint to provide noise reduced sonar domes

    NASA Astrophysics Data System (ADS)

    House, J. R.

    1997-10-01

    This paper concerns the noise and vibration advantages of an energy absorbing composite joint and its relevance to noise reduced glass reinforced polyester (GRP) sonar domes. Once installed on an operational boat, hydrodynamic flow and supporting structural induced vibrations cause the dome to vibrate, thus radiating noise and interfering with sonar sensor response. The results of a vibration transmissibility study on a GRP - steel interface are discussed as the first step in designing a composite viscoelastic joint that can act as a vibration sink to absorb flow generated and structure borne noise within GRP sonar domes. Preliminary investigations concerning the absorption of compressional waves by use of a tapered viscoelastic interlayer are discussed. It is shown that a tapered viscoelastic interlayer placed between a GRP beam and steel supporting substrate can produce a significant absorption of vibrational energy, reducing water borne radiated noise and providing a significantly quieter noise platform than conventional sonar jointing technology.

  4. Joint source based analysis of multiple brain structures in studying major depressive disorder

    NASA Astrophysics Data System (ADS)

    Ramezani, Mahdi; Rasoulian, Abtin; Hollenstein, Tom; Harkness, Kate; Johnsrude, Ingrid; Abolmaesumi, Purang

    2014-03-01

    We propose a joint Source-Based Analysis (jSBA) framework to identify brain structural variations in patients with Major Depressive Disorder (MDD). In this framework, features representing position, orientation and size (i.e. pose), shape, and local tissue composition are extracted. Subsequently, simultaneous analysis of these features within a joint analysis method is performed to generate the basis sources that show signi cant di erences between subjects with MDD and those in healthy control. Moreover, in a cross-validation leave- one-out experiment, we use a Fisher Linear Discriminant (FLD) classi er to identify individuals within the MDD group. Results show that we can classify the MDD subjects with an accuracy of 76% solely based on the information gathered from the joint analysis of pose, shape, and tissue composition in multiple brain structures.

  5. Composite structures; Proceedings of the 7th International Conference, Univ. of Paisley, United Kingdom, July 5-7, 1993

    Microsoft Academic Search

    I. H. Marshall

    1993-01-01

    The present volume on composite structures discusses energy absorbing structures, brittle matrix structures, damage tolerance, vibrations, and environmental effects. Attention is given to localized effects, shell structures, materials aspects, joints, and metal matrix composites. Topics addressed include design and development of anthromorphic robots with carbon fiber epoxy composite materials, failure analysis, buckling studies, and smart structures. Topics addressed include composite

  6. Biomechanical considerations in patellofemoral joint rehabilitation

    Microsoft Academic Search

    Lisa A. Steinkamp; Michael F. Dillingham; Mark D. Markel; Jennifer A. Hill; Kenton R. Kaufman

    1993-01-01

    Patellofemoral joint biomechanics during leg press and leg extension exercises were compared in 20 normal subjects (10 men, 10 women) aged 18 to 45 years. Knee moment, patellofemoral joint reaction force, and patellofemoral joint stress were calculated for each subject at four knee flexion angles (0°, 30°, 60°, and 90°) during leg press and leg extension exercises.All three parameters (knee

  7. of Concrete Pavements Joint PerformanCe

    E-print Network

    practitioners under- stand how to optimize concrete pavement joint perfor- mance through the identificationof Concrete Pavements Joint PerformanCe interim Guide for optimum JUNE 2012 #12;#12;Interim Guide for Optimum Joint Performance of Concrete Pavements i Technical Report Documentation Page 1. Report No. 2

  8. New insights in critical solder joint location

    Microsoft Academic Search

    Mitul Modi; Carolyn McCormick; Norman Armendariz

    2005-01-01

    Current numerical modeling approaches to assess BGA solder joint thermal mechanical fatigue, typically identify the max DNP (distance from neutral point) solder joint as the first to fail. An experimental and numerical analysis has shown that critical solder joints can be located interior to the max DNP location. In this work, FCBGA packages were subjected to accelerated thermal cycling stress.

  9. Translational stiffness of the replaced shoulder joint

    Microsoft Academic Search

    R. Oosterom; J. L. Herder; W. ?wi?szkowski; H. E. N. Bersee

    2003-01-01

    Results after a total shoulder arthroplasty in rheumatoid patients are poor, indicated by loosening of especially the glenoid component, bad joint functionality and the possibility of a joint dislocation. The failure mechanisms behind this are multiple, including patient, surgical and design factors. These results must be improved. At present, the optimal geometrical prosthesis component design, focused on joint conformity and

  10. 49 CFR 192.233 - Miter joints.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...MINIMUM FEDERAL SAFETY STANDARDS Welding of Steel in Pipelines § 192.233 Miter joints. (a) A miter joint on steel pipe to be operated at a pressure...than 3°. (b) A miter joint on steel pipe to be operated at a...

  11. 49 CFR 192.233 - Miter joints.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...MINIMUM FEDERAL SAFETY STANDARDS Welding of Steel in Pipelines § 192.233 Miter joints. (a) A miter joint on steel pipe to be operated at a pressure...than 3°. (b) A miter joint on steel pipe to be operated at a...

  12. 49 CFR 192.233 - Miter joints.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...MINIMUM FEDERAL SAFETY STANDARDS Welding of Steel in Pipelines § 192.233 Miter joints. (a) A miter joint on steel pipe to be operated at a pressure...than 3°. (b) A miter joint on steel pipe to be operated at a...

  13. Joints in deployable space truss structures

    NASA Technical Reports Server (NTRS)

    Rhodes, M.

    1988-01-01

    Since the response of deployable structural concepts being considered for the Large Deployable Reflector (LDR) backup structure will be dominated by the response of joints, the joint characteristics are significant. An overview is given of the research activities at LaRC on the static behavior of joints for deployable space truss structures. Since a pin-clevis-type joint will be utilized in deployable structures, an experimental research program to characterize the joint parameters which affect stiffness was conducted. An experimental research program was conducted on a second type of joint, referred to as a near-center latch joint. It was used in the center of members on the deployable truss structure for the Control of Flexible Structures (COFS) flight experiment. The test results of the near-center latch joint and the member with the joints indicated that the stiffness of the near-center joint is linear and stiffer than the stiffness of the total member, and that non-linearities in the stiffness characteristics of the total member were due to bending introduced at the ends of the member. The resulting data indicates that stiff linear folding joints can be designed and that bending load paths should be avoided whenever possible. In summary, for deployable structures, special attention to the joint and the structure design is required to minimize the undesirable structural non-linearities.

  14. Stabilization for chronic sternoclavicular joint instability.

    PubMed

    Lee, Sang-Uk; Park, Il-Jung; Kim, Young-Du; Kim, Yoon-Chung; Jeong, Changhoon

    2010-12-01

    We present a surgical reconstruction technique for chronic unstable sternoclavicular (SC) joint utilizing the tendon of sternocleidomastoid (SCM) muscle and additional augmentation utilizing the palmaris longus free tendon graft to secure the medial end of the clavicle to the first rib. This double stabilization procedure may strengthen the SC joint fixation for the chronic SC joint instability. PMID:20852846

  15. Navigating Joint Projects in Telephone Conversations

    ERIC Educational Resources Information Center

    Bangerter, Adrian; Clark, Herbert H.; Katz, Anna R.

    2004-01-01

    Conversation coordinates joint activities and the joint projects that compose them. Participants coordinate (1) vertical transitions on entering and exiting joint projects; and (2) horizontal transitions in continuing within them. Transitions are coordinated using project markers such as uh-huh, yeah, right, and okay. In the authors' proposal,…

  16. The frictional properties of joints in rock

    Microsoft Academic Search

    J. C. Jaeger

    1959-01-01

    Summary The conditions for sliding over artificial joint surfaces have been studied experimentally by cutting rock cylinders at various angles to their axes and studying slip over these surfaces in a triaxial testing apparatus. The types of joint used were: (i) filled with plaster to simulate a soft joint filling, (ii) bare surfaces ground approximately flat, and (iii) natural surfaces

  17. Septic arthritis of the acromioclavicular joint

    Microsoft Academic Search

    A. Blankstein; J. L. Amsallem; E. Rubinstein; H. Horoszowski; I. Farin

    1985-01-01

    A patient with isolated pyogenous arthritis of the acromioclavicular joint (A-C joint) caused by Streptococcus viridans is described. The patient had no underlying disease. Minor trauma preceded shortly the development of the septic process. The patient was treated successfully with surgical drainage and antibiotics. To our knowledge this is the first case report of septic arthritis of the A-C joint

  18. Evaluation and Treatment of Acromioclavicular Joint Injuries

    Microsoft Academic Search

    Augustus D. Mazzocca; Robert A. Arciero; James Bicos

    2007-01-01

    Acromioclavicular joint injuries and, more specifically, separations are commonplace both in general practice and during athletic participation. This article reviews the traditional classification as well as the clinical evaluation of patients with acute and chronic acromioclavicular joint separations. It also highlights many recent advances, principally in the anatomy and biomechanics of the acromioclavicular joint ligamentous complex. The concept of increases

  19. 32 CFR 536.54 - Joint tortfeasors.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...Defense 3 2012-07-01 2009-07-01 true Joint tortfeasors. 536.54 Section 536.54 National...Investigation and Processing of Claims § 536.54 Joint tortfeasors. When joint tortfeasors are liable, it is DA policy to...

  20. Joint News Release ELEVENTH ITER NEGOTIATIONS MEETING

    E-print Network

    Joint News Release ELEVENTH ITER NEGOTIATIONS MEETING CHENGDU , CHINA, 24OCTOBER 2005 Delegations of America met in CHENGDU on 24October 2005 to continue their work to reach agreement on the joint the project and its procurements, and the continuing joint drafting of the agreement on establishing

  1. 32 CFR 536.54 - Joint tortfeasors.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...Defense 3 2013-07-01 2013-07-01 false Joint tortfeasors. 536.54 Section 536.54 National...Investigation and Processing of Claims § 536.54 Joint tortfeasors. When joint tortfeasors are liable, it is DA policy to...

  2. 29 CFR 570.115 - Joint applicability.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Joint applicability. 570.115 Section 570...Labor Standards Act of 1938, as Amended Joint and Separate Applicability of Sections 12(a) and 12(c) § 570.115 Joint applicability. The child labor...

  3. 32 CFR 536.54 - Joint tortfeasors.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...Defense 3 2014-07-01 2014-07-01 false Joint tortfeasors. 536.54 Section 536.54 National...Investigation and Processing of Claims § 536.54 Joint tortfeasors. When joint tortfeasors are liable, it is DA policy to...

  4. 7 CFR 1956.110 - Joint debtors.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 2012-01-01 false Joint debtors. 1956.110 Section 1956.110...Settlement-Community and Business Programs § 1956.110 Joint debtors. Settlements may not be approved for one joint debtor unless approved for all...

  5. 7 CFR 1956.110 - Joint debtors.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 2014-01-01 false Joint debtors. 1956.110 Section 1956.110...Settlement-Community and Business Programs § 1956.110 Joint debtors. Settlements may not be approved for one joint debtor unless approved for all...

  6. 7 CFR 1956.110 - Joint debtors.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 2010-01-01 2009-01-01 true Joint debtors. 1956.110 Section 1956.110...Settlement-Community and Business Programs § 1956.110 Joint debtors. Settlements may not be approved for one joint debtor unless approved for all...

  7. JOINT DEGREE PROGRAMS DEFINITION AND POLICY

    E-print Network

    Omiecinski, Curtis

    1 JOINT DEGREE PROGRAMS DEFINITION AND POLICY: Within the fields of medicine and law, dual training for such complementary training can be demonstrated, the creation of a formal "Joint" degree program in which students or MD) offered at Penn State may be warranted. Such Joint degree programs enhance the educational

  8. Joint action: bodies and minds moving together

    E-print Network

    Richardson, Daniel C.

    Joint action: bodies and minds moving together Natalie Sebanz1 , Harold Bekkering2 and Gu¨ nther as individuals and as a species. Progress in understanding the cognitive and neural processes involved in joint perception and action in social context. In this article we outline how studies on joint attention, action

  9. Joint Seminar -Risk Management Institute and

    E-print Network

    Chaudhuri, Sanjay

    Joint Seminar - Risk Management Institute and Department of Finance Details of Seminar Date: 4 affine jump-diffusion models in capturing the joint dynamics of stock and option prices. We develop all the models we consider. Risk Management Institute Joint Seminar #12;

  10. Joint Kernel Learning for Supervised Image Segmentation

    E-print Network

    Yoo, Chang D.

    Joint Kernel Learning for Supervised Image Segmentation Jongmin Kim, Youngjoo Seo, Sanghyuk Park al- gorithm based on joint-kernelized structured prediction. In the proposed algorithm, correlation for struc- tured prediction were generally chosen to be linear with the model pa- rameter and joint feature

  11. 7 CFR 1956.110 - Joint debtors.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 2013-01-01 false Joint debtors. 1956.110 Section 1956.110...Settlement-Community and Business Programs § 1956.110 Joint debtors. Settlements may not be approved for one joint debtor unless approved for all...

  12. Joint Invariant Signatures Peter J. Olver

    E-print Network

    Olver, Peter

    Joint Invariant Signatures Peter J. Olver School of Mathematics University of Minnesota Minneapolis­Carlo Rota Abstract. A new, algorithmic theory of moving frames is applied to classify joint invariants and joint differential invariants of transformation groups. Equivalence and sym- metry properties

  13. 29 CFR 570.115 - Joint applicability.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Joint applicability. 570.115 Section 570...Labor Standards Act of 1938, as Amended Joint and Separate Applicability of Sections 12(a) and 12(c) § 570.115 Joint applicability. The child labor...

  14. 7 CFR 1956.110 - Joint debtors.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 2011-01-01 false Joint debtors. 1956.110 Section 1956.110...Settlement-Community and Business Programs § 1956.110 Joint debtors. Settlements may not be approved for one joint debtor unless approved for all...

  15. 29 CFR 570.115 - Joint applicability.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Joint applicability. 570.115 Section 570...Labor Standards Act of 1938, as Amended Joint and Separate Applicability of Sections 12(a) and 12(c) § 570.115 Joint applicability. The child labor...

  16. 38 CFR 4.66 - Sacroiliac joint.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...sharpening of the margins of the joint. Disability is manifest from...palpation and percussion over these joints, loss of normal quickness...flexion and extension of the hip. Traumatism is a rare cause...objective evidence of damage to the joint, and history of trauma...

  17. 38 CFR 4.66 - Sacroiliac joint.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...sharpening of the margins of the joint. Disability is manifest from...palpation and percussion over these joints, loss of normal quickness...flexion and extension of the hip. Traumatism is a rare cause...objective evidence of damage to the joint, and history of trauma...

  18. Evaluation of the Effect of Mega MSM on Improving Joint Function in Populations Experiencing Joint Degeneration

    PubMed Central

    Xu, Gang; Zhou, Tian; Gu, Yaqin; Wang, Qinping; Shariff, Mina; Gu, Pingping; Nguyen, Tuong; Shi, Rong; Rao, Jianyu

    2015-01-01

    Joint degeneration has become a commonplace problem in aging populations. The main clinical manifestations include joint pain, joint stiffness and joint swelling with functional disorder. Mega MSM is a nutritional supplement that may provide potential relief for joint problems associated with joint degeneration. The current experiment performed was a 12-week, randomized, double-blind, controlled study conducted on populations in China experiencing joint degeneration. The objective of the study was to determine whether the daily use of Mega MSM capsules could improve joint function, relieve symptoms of joint degeneration and improve the quality of life in aging populations. A total of 100 male and female participants over 50 years old who had at least one of the related symptoms of joint degeneration (joint pain, joint stiffness, joint swelling, difficulty walking, difficulty getting up from bed and difficulty going down stairs) were recruited and their symptoms of joint degeneration before and after the intervention were recorded. In this study, Mega MSM shows positive effects in improving joint function, relieving symptoms associated with joint degeneration and improving the quality of life in aging populations. PMID:26199577

  19. 26 CFR 1.6015-1 - Relief from joint and several liability on a joint return.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Relief from joint and several liability on a joint return. 1.6015-1 Section 1.6015-1...Returns Or Statements § 1.6015-1 Relief from joint and several liability on a joint return....

  20. Joint interaction with embedded concretions: joint loading congurations inferred from propagation paths

    E-print Network

    Engelder, Terry

    Joint interaction with embedded concretions: joint loading con®gurations inferred from propagation The interaction between propagating joints and embedded concretions in a Devonian black shale near Seneca Lake, NY, permits identi®cation of the loading con®gurations responsible for two joint sets of dierent ages striking

  1. 26 CFR 1.6015-1 - Relief from joint and several liability on a joint return.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 2012-04-01 false Relief from joint and several liability on a joint return. 1.6015-1 Section 1.6015-1...Returns Or Statements § 1.6015-1 Relief from joint and several liability on a joint return....

  2. 26 CFR 1.6015-1 - Relief from joint and several liability on a joint return.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Relief from joint and several liability on a joint return. 1.6015-1 Section 1.6015-1...Returns Or Statements § 1.6015-1 Relief from joint and several liability on a joint return....

  3. 26 CFR 1.6015-1 - Relief from joint and several liability on a joint return.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Relief from joint and several liability on a joint return. 1.6015-1 Section 1.6015-1...Returns Or Statements § 1.6015-1 Relief from joint and several liability on a joint return....

  4. Reduced tension sealant systems -- EIFS joint design properties and lamina stresses initiating substrate failure

    SciTech Connect

    Baerveldt, K. [Emseal Corp., Mississauga, Ontario (Canada)

    1996-12-31

    Canada Mortgage and Housing Corporation (CMHC) completed during 1994 a research program that investigated, amongst other aspects, joint design and sealant bond to EIF Systems. Eight different joint designs were tested as well as sealant bond strengths to the EIFS lamina (either finish or base coat). Polyurethane and silicone sealants as well as an impregnated expanding foam sealant composite were selected for testing based on the presumption of having either a low modulus characteristic, or of being representative of industry wide usage. Bond strength results indicated, that for the uniform samples tested, loads (stress) greater than 670 N (the cohesive strength of the EIFS lamina/EPS foam interface), will initiate substrate failure. Due to over-stressing of the EIFS lamina joint movement may occur without external visual signs. Capillaries or voids may be created either within the lamina or between basecoat and EPS foam that will effect short or long-term life expectancy. Of the joint design configurations tested, several could overly damage the EIFS lamina, even with limited movement. A series of joint designs has emerged based on either a binary sealant configuration or double joint with vented cavity (rain-screen principle) that show low lamina stress values. While these joints may not be fully pressure equalized rain-screen designs, the net effect is to prevent further moisture penetration into the EIF System.

  5. Interfacial metallurgy study of brazed joints between tungsten and fusion related materials for divertor design

    NASA Astrophysics Data System (ADS)

    Zhang, Yuxuan; Galloway, Alexander; Wood, James; Robbie, Mikael Brian Olsson; Easton, David; Zhu, Wenzhong

    2014-11-01

    In the developing DEMO divertor, the design of joints between tungsten to other fusion related materials is a significant challenge as a result of the dissimilar physical metallurgy of the materials to be joined. This paper focuses on the design and fabrication of dissimilar brazed joints between tungsten and fusion relevant materials such as EUROFER 97, oxygen-free high thermal conductivity (OFHC) Cu and SS316L using a gold based brazing foil. The main objectives are to develop acceptable brazing procedures for dissimilar joining of tungsten to other fusion compliant materials and to advance the metallurgical understanding within the interfacial region of the brazed joint. Four different butt-type brazed joints were created and characterised, each of which were joined with the aid of a thin brazing foil (Au80Cu19Fe1, in wt.%). Microstructural characterisation and elemental mapping in the transition region of the joint was undertaken and, thereafter, the results were analysed as was the interfacial diffusion characteristics of each material combination produced. Nano-indentation tests are performed at the joint regions and correlated with element composition information in order to understand the effects of diffused elements on mechanical properties. The experimental procedures of specimen fabrication and material characterisation methods are presented. The results of elemental transitions after brazing are reported. Elastic modulus and nano-hardness of each brazed joints are reported.

  6. 44 CFR 150.5 - Joint Public Safety Awards Board.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 2014-10-01 2014-10-01 false Joint Public Safety Awards Board. 150.5 Section...AWARDS TO PUBLIC SAFETY OFFICERS § 150.5 Joint Public Safety Awards Board. (a) A Joint Public Safety Awards Board (Joint...

  7. 44 CFR 150.5 - Joint Public Safety Awards Board.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 2013-10-01 2013-10-01 false Joint Public Safety Awards Board. 150.5 Section...AWARDS TO PUBLIC SAFETY OFFICERS § 150.5 Joint Public Safety Awards Board. (a) A Joint Public Safety Awards Board (Joint...

  8. Analysis of selected compression splice joint locations in a graphite-epoxy transport wing stub box

    Microsoft Academic Search

    Dawn C. Jegley

    1995-01-01

    Three critical compression splice joint locations in a stitched graphite-epoxy transport wing stub box have been analyzed to determine their expected structural performance. The wing box is representative of a section of a commercial transport wing box and was designed and constructed by McDonnell Douglas Aerospace Company as part of the NASA Advanced Composites Technology (ACT) program. The results of

  9. TECHNICAL NOTE: Observations on the use of a viscoelastic joint to provide noise reduced sonar domes

    Microsoft Academic Search

    J. R. House

    1997-01-01

    This paper concerns the noise and vibration advantages of an energy absorbing composite joint and its relevance to noise reduced glass reinforced polyester (GRP) sonar domes. Once installed on an operational boat, hydrodynamic flow and supporting structural induced vibrations cause the dome to vibrate, thus radiating noise and interfering with sonar sensor response. The results of a vibration transmissibility study

  10. Analysis of tongue and groove joints for thick laminatesq Karel Matous, George J. Dvorak*

    E-print Network

    Matous, Karel

    evaluation of local stresses in the adhesive and adherends is presented for a tongue-and-groove joint of a homogenized thick composite laminate to steel plate. The quasi-isotropic laminate is made of glass fabric/vinyl ester plies. Most results are obtained for elastic response of the Dexter-Hysol 9338 adhesive

  11. Milk lipid and protein traffic in mammary epithelial cells: joint and independent pathways

    E-print Network

    Boyer, Edmond

    Review Milk lipid and protein traffic in mammary epithelial cells: joint and independent pathways, France Abstract -- In mammary epithelial cells, milk lipids and proteins are synthesised in the same com. These processes assure a relatively constant composition of milk but it is not known whether lipid and protein

  12. Towards approximate models of coulomb frictional moments in: I) revolute pin joints and II) spherical-socket ball joints

    E-print Network

    of Engineering Science Simon Fraser University 8888 University Drive Burnaby, British Columbia Canada V5A 1S6 e consist of joints and linkages, and rotary joints are the most commonly used type of joints. Rotary joints

  13. End bearing and joint strengths of COM-PLY joists

    NASA Astrophysics Data System (ADS)

    Wittenberg, D. C.

    1981-07-01

    House framing with particleboard cores and veneer facings is evaluated. These COM-PLY composite materials were designed to be used interchangeably with conventional lumber and plywood in housing. The COM-PLY floor joists supported by four common methods were investigated: end bearing on wood plates, ledgers with end notching, end bearing on metal joist hangers, and nails only. End bearing and joint strength of COM-PLY joists proved satisfactory for all four common methods of support. Tabular data and illustrative photographs and drawings are provided.

  14. Ultrasonic Probing Of Complexly Shaped Joints

    NASA Technical Reports Server (NTRS)

    Madaras, Eric I.

    1993-01-01

    Technique developed involves use of ultrasonics to inspect first bond surfaces of solid-rocket-motor joints. By fitting pieces of insulating materials to mate exactly with complicated shapes of affected parts of insulation, complicated shapes redefined into simpler ones probed more easily. When technique used to insonify from insulation side, one readily detects difference between disbond and good bond. Same technique applied to field tang joints, field clevis joints, and aft-dome-to-fixed-nozzle-housing attachment points. Although developed for inspecting joints in solid rocket motors, also applicable to nondestructive evaluation of other complicated joints.

  15. Prevention of Periprosthetic Joint Infection

    PubMed Central

    Shahi, Alisina; Parvizi, Javad

    2015-01-01

    Prosthetic joint infection (PJI) is a calamitous complication with high morbidity and substantial cost. The reported incidence is low but it is probably underestimated due to the difficulty in diagnosis. PJI has challenged the orthopaedic community for several years and despite all the advances in this field, it is still a real concern with immense impact on patients, and the healthcare system. Eradication of infection can be very difficult. Therefore, prevention remains the ultimate goal. The medical community has executed many practices with the intention to prevent infection and treat it effectively when it encounters. Numerous factors can predispose patients to PJI. Identifying the host risk factors, patients’ health modification, proper wound care, and optimizing operative room environment remain some of the core fundamental steps that can help minimizing the overall incidence of infection. In this review we have summarized the effective prevention strategies along with the recommendations of a recent International Consensus Meeting on Surgical Site and Periprosthetic Joint Infection. PMID:26110171

  16. Metal-ceramic joint assembly

    DOEpatents

    Li, Jian (New Milford, CT)

    2002-01-01

    A metal-ceramic joint assembly in which a brazing alloy is situated between metallic and ceramic members. The metallic member is either an aluminum-containing stainless steel, a high chromium-content ferritic stainless steel or an iron nickel alloy with a corrosion protection coating. The brazing alloy, in turn, is either an Au-based or Ni-based alloy with a brazing temperature in the range of 9500 to 1200.degree. C.

  17. Boom and chassis articulation joints

    NASA Technical Reports Server (NTRS)

    Murphy, Joel T., Jr.; Nguyen, Vien; Turner, Bonnie; Wheeler, Bobby; Williams, Kimberlyn

    1992-01-01

    The primary goal of our design project was to develop articulation joints for the chassis and boom of the proof-of-concept lunar vehicle. This is an ongoing project and the work of previous student groups was extensively reviewed. Some of the ideas generated are variations of past proposals. Although the project is funded by NASA/USRA, it is totally a student design effort.

  18. Impact reliability of solder joints

    Microsoft Academic Search

    M. Date; T. Shoji; M. Fujiyoshi; K. Sato; K. N. Tu

    2004-01-01

    Owing to the impact reliability concern of portable devices, the impact toughness of solder joints was evaluated quantitatively by means of a miniature Charpy test, in which the shear rate was approximately 1 m\\/s. Four different solder balls (eutectic SnPb, near eutectic SnAgCu, eutectic SnZn and SnZnBi) were bonded to Cu or immersion Au\\/electroless Ni-P pads, and subsequently some of

  19. Spring joint with overstrain sensor

    NASA Technical Reports Server (NTRS)

    Phelps, Peter M. (Inventor); Gaither, Bryan W. (Inventor)

    2011-01-01

    A flexible joint may include a conductive compression spring and a pair of non-conductive spring cages disposed at opposite ends of the compression spring to support the compression spring. A conductive member disposed inside the compression spring may extend between the pair of spring cages. One end of the conductive member may be fixed for movement with one of the spring cages and another end of the conductive member may be fixed for movement with the other of the spring cages.

  20. Joint Commission on rock properties

    NASA Astrophysics Data System (ADS)

    A joint commission on Rock Properties for Petroleum Engineers (RPPE) has been established by the International Society of Rock Mechanics and the Society of Petroleum Engineers to set up data banks on the properties of sedimentary rocks encountered during drilling. Computer-based data banks of complete rock properties will be organized for sandstones (GRESA), shales (ARSHA) and carbonates (CARCA). The commission hopes to access data sources from members of the commission, private companies and the public domain.

  1. Posterior glenohumeral joint capsule contracture.

    PubMed

    Dashottar, Amitabh; Borstad, John

    2012-10-01

    Glenohumeral joint posterior capsule contracture may cause shoulder pain by altering normal joint mechanics. Contracture is commonly noted in throwing athletes but can also be present in nonthrowers. The cause of contracture in throwing athletes is assumed to be a response to the high amount of repetitive tensile force placed on the tissue, whereas the mechanism of contracture in nonthrowers is unknown. It is likely that mechanical and cellular processes interact to increase the stiffness and decrease the compliance of the capsule, although the exact processes that cause a contracture have not been confirmed. Cadaver models have been used to study the effect of posterior capsule contracture on joint mechanics and demonstrate alterations in range of motion and in humeral head kinematics. Imaging has been used to assess posterior capsule contracture, although standard techniques and quantification methods are lacking. Clinically, contracture manifests as a reduction in glenohumeral internal rotation and/or cross body adduction range of motion. Stretching and manual techniques are used to improve range of motion and often decrease symptoms in painful shoulders. PMID:24265649

  2. Analysis of truss, beam, frame, and membrane components. [composite structures

    NASA Technical Reports Server (NTRS)

    Knoell, A. C.; Robinson, E. Y.

    1975-01-01

    Truss components are considered, taking into account composite truss structures, truss analysis, column members, and truss joints. Beam components are discussed, giving attention to composite beams, laminated beams, and sandwich beams. Composite frame components and composite membrane components are examined. A description is given of examples of flat membrane components and examples of curved membrane elements. It is pointed out that composite structural design and analysis is a highly interactive, iterative procedure which does not lend itself readily to characterization by design or analysis function only.-

  3. Arthroscopically assisted acromioclavicular joint reconstruction.

    PubMed

    Baumgarten, Keith M; Altchek, David W; Cordasco, Frank A

    2006-02-01

    Arthroscopically assisted acromioclavicular joint reconstruction avoids the large incisions necessary with open reconstructions. This acromioclavicular joint reconstruction technique via the subacromial space does not violate the rotator interval or require screw removal. The patient is placed in a modified beach-chair position. The arthroscope is placed into the subacromial space, and a bursectomy is performed through a lateral subacromial portal. The coracoacromial ligament is released from the acromion with an electrocautery and an arthroscopic elevator. A nonabsorbable suture is passed through the coracoacromial ligament with a suture passer, and an arthroscopic suture grasper is used to deliver both ends of the suture out through the lateral portal. The coracoid is identified and isolated using a radiofrequency ablator placed through the anterior portal while visualizing through the lateral portal. A percutaneous shuttle device is passed through the skin superomedial to the coracoid. The shuttle is visualized entering superior to the coracoid and is passed just medial to the coracoid. Once the tip of the shuttle can be visualized in the recess inferior to the coracoid, the shuttle loop is advanced. A suture grasper is used to deliver both ends of the shuttle out through the anterior portal. A semitendinosus allograft is used to reconstruct the coracoclavicular ligament. A nonabsorbable suture is passed through both ends of the allograft. Three strands of nonabsorbable suture are braided together. The tendon and the braided suture are shuttled around the coracoid. At this point, both the braided suture and the allograft tendon enter the anterior portal, wrap around the coracoid base, and exit the anterior portal. A 3-cm incision is made over the distal clavicle. A hole is drilled through the clavicle with a 5-mm drill. A loop of 22-gauge wire is passed through the hole in the clavicle, and a looped suture is shuttled through the hole. A curved clamp is used to create a tunnel from the acromioclavicular joint, under the deltoid, to the anterior portal. The ends of the braided suture and the tendon sutures are grasped by the clamp and pulled out the acromioclavicular joint incision. The limbs of the braided suture and the tendon suture that pass medial to the coracoid are shuttled through the hole in the clavicle using the looped suture that was previously passed through the clavicle. The acromioclavicular joint is reduced by pushing down on the distal clavicle with a bone tamp while simultaneously lifting the acromion upward by superiorly loading the humerus at the elbow. Once the acromioclavicular joint is reduced or slightly over-reduced, the braided suture is tied down securely. The acromioclavicular joint should remain reduced even after the manual reduction maneuver is released. The semitendinosus allograft is tensioned around the distal end of the clavicle and sutured to itself with a nonabsorbable suture. The released coracoacromial ligament is retrieved from the clavicular incision and sutured to the distal clavicle and semitendinosus allograft. The incision is closed in standard fashion, and a sling is applied. PMID:16458813

  4. Composite Materials

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Composites are lighter and stronger than metals. Aramid fibers like Kevlar and Nomex were developed by DuPont Corporation and can be combined in a honeycomb structure which can give an airplane a light, tough structure. Composites can be molded into many aerodynamic shapes eliminating rivets and fasteners. Langley Research Center has tested composites for both aerospace and non-aerospace applications. They are also used in boat hulls, military shelters, etc.

  5. Age-related mobility loss is joint-specific: an analysis from 6,000 Flexitest results.

    PubMed

    Medeiros, Hugo Baptista de Oliveira; de Araújo, Denise Sardinha Mendes Soares; de Araújo, Claudio Gil Soares

    2013-12-01

    Although aging is commonly linked to a reduction in joint range of motion, it is unclear if all body joints behave similarly. To address this issue, the main purpose of this study was to compare age-related loss of mobility of seven body joints. A total of 6,000 participants (3,835 men and 2,165 women) aged 5 to 92 years took part in this study. The maximal passive range of motion of 20 movements was evaluated by Flexitest, and each movement was scored from 0 to 4. Composite scores were obtained for each of seven joints and for overall flexibility (Flexindex (FLX)) by adding individual movement scores. Confirming previous findings, FLX systematically decreased with aging (p < .001), with female participants being more flexible for all ages (p < 0.001) and having a more gradual, 0.6% vs. 0.8%/year, age reduction (p < .001). Starting at 30 and 40 years, respectively, for male and female participants, the relative contribution of each composite joint score to FLX dramatically changed. Shoulder contribution to FLX male's score went from 13.9% at 28 years of age to only 5.2% at 85 years of age. In general, proportionally, shoulder and trunk became less flexible, while elbow and knee mobility was preserved to a greater extent. Our findings indicated that age-related loss of mobility is rather joint-specific, which could be related to distinct routine usage patterns of the major body joints along life. PMID:23529505

  6. Energetic composites

    DOEpatents

    Danen, Wayne C. (Los Alamos, NM); Martin, Joe A. (Espanola, NM)

    1993-01-01

    A method for providing chemical energy and energetic compositions of matter consisting of thin layers of substances which will exothermically react with one another. The layers of reactive substances are separated by thin layers of a buffer material which prevents the reactions from taking place until the desired time. The reactions are triggered by an external agent, such as mechanical stress or an electric spark. The compositions are known as metastable interstitial composites (MICs). This class of compositions includes materials which have not previously been capable of use as energetic materials. The speed and products of the reactions can be varied to suit the application.

  7. Fiber-optic Raman Spectroscopy of Joint Tissues

    PubMed Central

    Esmonde-White, Karen A.; Esmonde-White, Francis W.L.; Morris, Michael D.

    2011-01-01

    In this study, we report adaptation of Raman spectroscopy for arthroscopy of joint tissues using a custom-built fiber optic probe. Differentiation of healthy and damaged tissue or examination of subsurface tissue, such as subchondral bone, is a challenge in arthroscopy because visual inspection may not provide sufficient contrast. Discrimination of healthy versus damaged tissue may be improved by incorporating point spectroscopy or hyperspectral imaging into arthroscopy where contrast is based on molecular structure or chemical composition. Articular joint surfaces of knee cadaveric human tissue and tissue phantoms were examined using a custom-designed Raman fiber optic probe. Fiber-optic Raman spectra were compared against reference spectra of cartilage, subchondral bone and cancellous bone collected using Raman microspectroscopy. In fiber-optic Raman spectra of the articular surface, there was an effect of cartilage thickness on recovery of signal from subchondral bone. At sites with intact cartilage, the bone mineralization ratio decreased but there was a minimal effect in the bone mineral chemistry ratios. Tissue phantoms were prepared as experimental models of the osteochondral interface. Raman spectra of tissue phantoms suggested that optical scattering of cartilage has a large effect on the relative cartilage and bone signal. Finite element analysis modeling of light fluence in the osteochondral interface confirmed experimental findings in human cadaveric tissue and tissue phantoms. These first studies demonstrate proof of principle for Raman arthroscopic measurement of joint tissues and provide a basis for future clinical or animal model studies. PMID:21359366

  8. Low-activation joining of SiC\\/SiC composites for fusion applications

    Microsoft Academic Search

    Charles H. Henager; R. J. Kurtz

    2011-01-01

    Research at PNNL has been directed at high-strength, low-activation joints using solid-state displacement reactions. This paper reports on further development and optimization of displacement reaction joints for the TITAN collaboration. The results reveal that fully dense and high-quality joints between SiC-composite bars are fabricated at 1623 K-1723 K using 30 MPa pressure in purified argon atmospheres. Scanning electron micrographs reveal

  9. Low-activation joining of SiC\\/SiC composites for fusion applications

    Microsoft Academic Search

    Charles H. Henager; Richard J. Kurtz; M. Ferraris

    2011-01-01

    Research at PNNL has been directed at high-strength, low-activation joints using solid-state displacement reactions. This paper reports on further development and optimization of displacement reaction joints for the TITAN collaboration. The results reveal that fully dense and high-quality joints between SiC-composite bars are fabricated at 1623K–1723K using 30MPa pressure in purified argon atmospheres. Scanning electron micrographs reveal typical interpenetrating phase

  10. Failure Predictions of Out-of-Autoclave Sandwich Joints with Delaminations under Flexure Loads

    NASA Technical Reports Server (NTRS)

    Nordendale, Nikolas; Goyal, Vinay; Lundgren, Eric; Patel, Dhruv; Farrokh, Babak; Jones, Justin; Fischetti, Grace; Segal, Kenneth

    2015-01-01

    An analysis and a test program was conducted to investigate the damage tolerance of composite sandwich joints. The joints contained a single circular delamination between the face-sheet and the doubler. The coupons were fabricated through out-of-autoclave (OOA) processes, a technology NASA is investigating for joining large composite sections. The four-point bend flexure test was used to induce compression loading into the side of the joint where the delamination was placed. The compression side was chosen since it tends to be one of the most critical loads in launch vehicles. Autoclave cure was used to manufacture the composite sandwich sections, while the doubler was co-bonded onto the sandwich face-sheet using an OOA process after sandwich panels were cured. A building block approach was adopted to characterize the mechanical properties of the joint material, including the fracture toughness between the doubler and facesheet. Twelve four-point-bend samples were tested, six in the sandwich core ribbon orientation and six in sandwich core cross-ribbon direction. Analysis predicted failure initiation and propagation at the pre-delaminated location, consistent with experimental observations. A building block approach using fracture analyses methods predicted failure loads in close agreement with tests. This investigation demonstrated a small strength reduction due to a flaw of significant size compared to the width of the sample. Therefore, concerns of bonding an OOA material to an in-autoclave material was mitigated for the geometries, materials, and load configurations considered.

  11. Quantification of Energy Release in Composite Structures

    NASA Technical Reports Server (NTRS)

    Minnetyan, Levon

    2003-01-01

    Energy release rate is usually suggested as a quantifier for assessing structural damage tolerance. Computational prediction of energy release rate is based on composite mechanics with micro-stress level damage assessment, finite element structural analysis and damage progression tracking modules. This report examines several issues associated with energy release rates in composite structures as follows: Chapter I demonstrates computational simulation of an adhesively bonded composite joint and validates the computed energy release rates by comparison with acoustic emission signals in the overall sense. Chapter II investigates the effect of crack plane orientation with respect to fiber direction on the energy release rates. Chapter III quantifies the effects of contiguous constraint plies on the residual stiffness of a 90 ply subjected to transverse tensile fractures. Chapter IV compares ICAN and ICAN/JAVA solutions of composites. Chapter V examines the effects of composite structural geometry and boundary conditions on damage progression characteristics.

  12. Quantification of Energy Release in Composite Structures

    NASA Technical Reports Server (NTRS)

    Minnetyan, Levon; Chamis, Christos C. (Technical Monitor)

    2003-01-01

    Energy release rate is usually suggested as a quantifier for assessing structural damage tolerance. Computational prediction of energy release rate is based on composite mechanics with micro-stress level damage assessment, finite element structural analysis and damage progression tracking modules. This report examines several issues associated with energy release rates in composite structures as follows: Chapter I demonstrates computational simulation of an adhesively bonded composite joint and validates the computed energy release rates by comparison with acoustic emission signals in the overall sense. Chapter II investigates the effect of crack plane orientation with respect to fiber direction on the energy release rates. Chapter III quantifies the effects of contiguous constraint plies on the residual stiffness of a 90 deg ply subjected to transverse tensile fractures. Chapter IV compares ICAN and ICAN/JAVA solutions of composites. Chapter V examines the effects of composite structural geometry and boundary conditions on damage progression characteristics.

  13. Biotribology of artificial hip joints

    PubMed Central

    Di Puccio, Francesca; Mattei, Lorenza

    2015-01-01

    Hip arthroplasty can be considered one of the major successes of orthopedic surgery, with more than 350000 replacements performed every year in the United States with a constantly increasing rate. The main limitations to the lifespan of these devices are due to tribological aspects, in particular the wear of mating surfaces, which implies a loss of matter and modification of surface geometry. However, wear is a complex phenomenon, also involving lubrication and friction. The present paper deals with the tribological performance of hip implants and is organized in to three main sections. Firstly, the basic elements of tribology are presented, from contact mechanics of ball-in-socket joints to ultra high molecular weight polyethylene wear laws. Some fundamental equations are also reported, with the aim of providing the reader with some simple tools for tribological investigations. In the second section, the focus moves to artificial hip joints, defining materials and geometrical properties and discussing their friction, lubrication and wear characteristics. In particular, the features of different couplings, from metal-on-plastic to metal-on-metal and ceramic-on-ceramic, are discussed as well as the role of the head radius and clearance. How friction, lubrication and wear are interconnected and most of all how they are specific for each loading and kinematic condition is highlighted. Thus, the significant differences in patients and their lifestyles account for the high dispersion of clinical data. Furthermore, such consideration has raised a new discussion on the most suitable in vitro tests for hip implants as simplified gait cycles can be too far from effective implant working conditions. In the third section, the trends of hip implants in the years from 2003 to 2012 provided by the National Joint Registry of England, Wales and Northern Ireland are summarized and commented on in a discussion. PMID:25621213

  14. Structural and Damage Assessment of Multi-Section Modular Hybrid Composite Wind Turbine Blade 

    E-print Network

    Nanami, Norimichi

    2014-07-25

    computational design concept that includes a multi-section modular hybrid composite wind turbine blade with successful joints while maintaining structural integrity and stability requirements. The configuration of the blade will simplify manufacturing...

  15. Development and Characterization of Novel Alumina Based Ceramic Matrix Composites for Energy Efficient Sliding Applications

    E-print Network

    Paluri, Rajeshwari S. Lakshmi

    2012-10-19

    where high wear resistance is required, such as pump bearings, seal rings, valve seats, piston components, gears, cutting tool inserts and artificial joints. We propose to develop a novel alumina based ceramic composite to enhance its surface...

  16. Nano-Material Aspects of Shock Absorption in Bone Joints

    PubMed Central

    Tributsch, H; Copf, F; Copf, p; Hindenlang, U; Niethard, F.U; Schneider, R

    2010-01-01

    This theoretical study is based on a nano-technological evaluation of the effect of pressure on the composite bone fine structure. It turned out, that the well known macroscopic mechano-elastic performance of bones in combination with muscles and tendons is just one functional aspect which is critically supported by additional micro- and nano- shock damping technology aimed at minimising local bone material damage within the joints and supporting spongy bone material. The identified mechanisms comprise essentially three phenomena localised within the three–dimensional spongy structure with channels and so called perforated flexible tensulae membranes of different dimensions intersecting and linking them. Kinetic energy of a mechanical shock may be dissipated within the solid-liquid composite bone structure into heat via the generation of quasi-chaotic hydromechanic micro-turbulence. It may generate electro-kinetic energy in terms of electric currents and potentials. And the resulting specific structural and surface electrochemical changes may induce the compressible intra-osseal liquid to build up pressure dependent free chemical energy. Innovative bone joint prostheses will have to consider and to be adapted to the nano-material aspects of shock absorption in the operated bones. PMID:21625375

  17. Composite material

    Microsoft Academic Search

    Stacy A. Hutchens; Jonathan Woodward; Barbara R. Evans; Hugh M. ONeill

    2012-01-01

    A composite biocompatible hydrogel material includes a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa. A calcium comprising salt is disposed in at least some of the pores. The porous polymer matrix can comprise cellulose, including bacterial cellulose. The composite can be used as a bone graft

  18. Electrode compositions

    DOEpatents

    Block, J.; Fan, X.

    1998-10-27

    An electrode composition is described for use as an electrode in a non-aqueous battery system. The electrode composition contains an electrically active powder in a solid polymer and, as a dispersant, a C{sub 8}-C{sub 15} alkyl capped oligomer of a hexanoic acid that is electrochemically inert at 2.5--4.5 volts.

  19. Management of acromioclavicular joint injuries.

    PubMed

    Stucken, Charlton; Cohen, Steven B

    2015-01-01

    Although recent advances have been made in the treatment of acromioclavicular (AC) joint injuries, they are still challenging for shoulder surgeons. There is a consensus that type I and II injuries should be treated nonoperatively, whereas acute type IV, V, and VI injuries should be treated surgically. There is no algorithm for correctly diagnosing and treating type III injuries, but the current trend is toward nonoperative treatment except for those with persistent symptoms and functional limitations after a course of conservative management. If surgery is indicated, newer anatomic techniques of reconstructing the coracoclavicular (CC) and AC ligaments are recommended. PMID:25435035

  20. Space nuclear system expansion joints

    NASA Technical Reports Server (NTRS)

    Whitaker, W. D.; Shimazki, T. T.

    1973-01-01

    The engineering, design, and fabrication status of the expansion joint unit (EJU) to be employed in the NaK primary coolant piping loop of the 5-kwe Reactor thermoelectric system are described. Four EJU's are needed in the NaK primary coolant piping loop. The four EJU's which will be identical, utilize bellows as the flexing member, are hermetically sealed, and provide double containment. The bellows are of a nested-formed design, and are to be constructed of 1-ply thickness of 0.010-in. Inconel 718. The EJU's provide a minimum piping load margin of safety of +0.22.

  1. Factors to consider in joint prosthesis systems

    PubMed Central

    Wolford, Larry M.

    2006-01-01

    In joint reconstruction, the techniques and materials that provide the best outcomes for patients have been debated. The main points of controversy relate to the use of hemiarthroplasties versus total joint prostheses with metal-on-metal versus metal-on-polyethylene articulations. This article investigates these areas as well as the applicability of the techniques and materials and the complications that can occur. Hypersensitivity to materials used in joint prostheses is relatively common but often unrecognized. Although the discussion applies to all joints, the temporomandibular joint (TMJ) is emphasized. For TMJ reconstruction, metal-on-polyethylene articulation in total joint prostheses provides better treatment outcomes than metal-on-metal articulation. PMID:17252041

  2. Osteoarthritis joint pain: the cytokine connection.

    PubMed

    Miller, Rachel E; Miller, Richard J; Malfait, Anne-Marie

    2014-12-01

    Osteoarthritis is a chronic and painful disease of synovial joints. Chondrocytes, synovial cells and other cells in the joint can express and respond to cytokines and chemokines, and all of these molecules can also be detected in synovial fluid of patients with osteoarthritis. The presence of inflammatory cytokines in the osteoarthritic joint raises the question whether they may directly participate in pain generation by acting on innervating joint nociceptors. Here, we first provide a systematic discussion of the known proalgesic effects of cytokines and chemokines that have been detected in osteoarthritic joints, including TNF-?, IL-1, IL-6, IL-15, IL-10, and the chemokines, MCP-1 and fractalkine. Subsequently, we discuss what is known about their contribution to joint pain based on studies in animal models. Finally, we briefly discuss limited data available from clinical studies in human osteoarthritis. PMID:25066335

  3. Global-Local Finite Element Analysis for Thermo-Mechanical Stresses in Bonded Joints

    NASA Technical Reports Server (NTRS)

    Shkarayev, S.; Madenci, Erdogan; Camarda, C. J.

    1997-01-01

    An analysis of adhesively bonded joints using conventional finite elements does not capture the singular behavior of the stress field in regions where two or three dissimilar materials form a junction with or without free edges. However, these regions are characteristic of the bonded joints and are prone to failure initiation. This study presents a method to capture the singular stress field arising from the geometric and material discontinuities in bonded composites. It is achieved by coupling the local (conventional) elements with global (special) elements whose interpolation functions are constructed from the asymptotic solution.

  4. Effect of high temperature aging on bonded and weld bonded joints

    NASA Technical Reports Server (NTRS)

    Vaughan, R. W.

    1975-01-01

    Development of adhesives for applications requiring long-term service at temperatures up to 600 F is discussed. This development work utilizes polyimide (PI) and polyphenylquinoxaline (PPQ) resin technology worked out previously. The resultant adhesives are evaluated in structural joints of titanium, steel and composite adherends and in honeycomb sandwich panels. Suitable adhesives also are evaluated in weld bonded titanium alloy joints. Testing includes determination of long-term aging of stressed and unstressed specimens at temperatures from about 450 F to 600 F as well as under dynamic fatigue conditions.

  5. Properties of Underwater Coated Electrode Welded Joints

    Microsoft Academic Search

    Constantin Miholc?; Elena Scutelnicu; Aurelia Mihailescu

    The paper presents the results of two comparative studies concerning some properties of underwater air-water coated-electrode welded joints (fillet and butt joints). The testes were performed using normal strength naval steel and hydro-protected medium coated-electrode (Ti). The welding environmental factors were accorded to the Romanian Register of Shipping regulations. The mechanical properties and HV 10 hardness of the welded joints

  6. Advances in reconstruction of digital joints.

    PubMed

    Schenck, R R

    1997-01-01

    The recent development of dynamic traction provides several advantages for the treatment of intra-articular fractures of the hand: Ligamentotaxis reduces fracture fragments and realigns joint surfaces, Contracture of joint ligament and periarticular structures is prevented, Collapse of fracture fragments is prevented, Cartilage healing and regeneration are enhanced, Joint mobility is retained, Extensive surgery may be avoided, As Leonardo da Vinci stated, "To understand motion is to understand nature." PMID:9211036

  7. Hydraulic-Leak Detector for Hidden Joints

    NASA Technical Reports Server (NTRS)

    Anderson, G. E.; Loo, S.

    1986-01-01

    Slow leakage of fluid made obvious. Indicator consists of wick wrapped at one end around joint to be monitored. Wick absorbs hydraulic fluid leaking from joint and transmits to opposite end, located outside cover plate and visible to inspector. Leakage manifested as discoloration of outside end of wick. Indicator reveals leaks in hidden fittings on hydraulic lines. Fast inspection of joints without disassembly. Used in aerospace, petroleum, chemical, nuclear, and other industries where removing covers for inspection impossible, difficult, or time-consuming.

  8. Joint For Erectable and Collapsible Frames

    NASA Technical Reports Server (NTRS)

    Pelischek, T. E.

    1985-01-01

    Joint mechanism allows truss structure to be folded and stowed in small space. Mechanism includes hinge attached to two truss elements connected by two links, tension bar, and compression bar. When folded elements are released, springs in joint mechanism rotate truss elements about hinge and lock mechanism to form single member. Developed for structures erected in space (antennas, solar panels, solar sails, and masts), joint mechanism adaptable to window-opening struts, folding furniture and television antennas.

  9. Feature selection for automatic solder joint inspection

    E-print Network

    Lee, Cheng-Cheng

    1987-01-01

    . Special thanks go to the Program for Automation in Manufacturing (PAM), Texas AkM University System for their support of this research, Mr. Jim Creiman of Westinghouse Electric Corporation who provided the circuit hoards, and Mr. Paul Collier of Texas... little solder. ""hPI 'i' ', l(tsW Fig. . '3. i2 !iol~lrr p~inl wII h nsssInL l~ n(J. Fig. 3. 13 Solder joint with a pin hole. Fig. 3. 14 Solder joint with no solder. Fig. 3, 15 Solder joint with poor wetting on lead. Fig. 3. 16 Solder joint...

  10. Effects of joint capsule tissue on cartilage degradation in an in vitro joint injury model

    E-print Network

    Lin, Stephanie Norris, 1980-

    2004-01-01

    Osteoarthritis is a degenerative disease of the whole joint that affects an estimated 20.7 million Americans. Traumatic joint injury causes an increase in risk for the development of osteoarthritis. A previously developed ...

  11. Temporomandibular joint replacement periprosthetic joint infections: a review of early diagnostic testing options.

    PubMed

    Mercuri, L G

    2014-10-01

    The incidence of a periprosthetic joint infection is uncommon after total joint replacement. Since the clinical, psychological, and economic consequences of this complication are substantial, the development of management algorithms based on early diagnostic testing has been the subject of continued exploration in the orthopaedic literature. While there has been discussion of this topic in the total temporomandibular joint replacement literature and preliminary management algorithms have been established, no diagnostic testing protocols have been proposed or studied for the management of early and/or late periprosthetic joint infections. This paper will review the classification of periprosthetic joint infections, the associated risk factors, the clinical sensitivity and specificity of laboratory and imaging diagnostic studies and their utility in the management of early and late onset orthopaedic periprosthetic joint infections. This review may provide an initial framework for the use of early diagnostic testing for the management of total temporomandibular joint replacement periprosthetic joint infections and stimulate further investigation into this topic. PMID:25048029

  12. [The pathology of temporomandibular joint luxations--anatomical studies on temporomandibular joint preparations].

    PubMed

    Pinkert, R

    1976-01-01

    After a description of the published hypothesis of luxation and subluxation in the temporomandibular joint the preparations of five temporomandibular joints is described. The results refer to the movement of the discus and the capitulum mandibulae and to the effects of the musculus temporalis and of the facies articularis ossis temporalis. In addition a hypothesis is established according to which the temporomandibular-joint-luxation may be considered to occur in the menisco-condylar part of the joint. PMID:141833

  13. Analytical and experimental methods for adhesively bonded joints subjected to high temperatures

    NASA Astrophysics Data System (ADS)

    Gustafson, Peter A.

    2008-10-01

    Recent advances in material systems have expanded the temperature range over which adhesively bonded composite joints can be used. In this work, several tools are developed for use in modeling joints over a broad range of temperatures. First, a set of dimensionless parameters is established which can be used for analysis of joint performance for an orthotropic symmetric double lap joint. A critical dimensionless ratio of mechanical and thermal loads is identified. The ratio predicts characteristics of the resulting stress distribution. A bonded joint finite element is also developed, wherein a joint-specific finite element is formulated based on an analytical solution. The resulting element allows for mesh-independent joint evaluation and multi-joint simulation at a system or vehicle level. As a mid-level analysis technique, the element has significant predictive and cost advantages over the previously available methods. An advanced analysis technique, the discrete cohesive zone method, is developed and demonstrated in a general element formulation. Initially, the element is examined from the perspective of computational efficiency and robustness. Two efficient traction laws are formulated and are compared to a traction law that is in common use. The element is subsequently used to investigate the interactions of adhesive parameters in standard adhesive characterization experiments. This quantification of experimental sensitivities allows for a deliberate mapping of cumulative experimental results to an appropriate set of model constitutive parameters. With knowledge of the parameter interactions, a set of experimental results are interpreted to determine a set of adhesive constitutive parameters for T650/AFR-PE-4/FM680-1, a high temperature material system of current interest.

  14. Joint Control for Dummies: An Elaboration of Lowenkron's Model of Joint (Stimulus) Control

    ERIC Educational Resources Information Center

    Sidener, David W.

    2006-01-01

    The following paper describes Lowenkron's model of joint (stimulus) control. Joint control is described as a means of accounting for performances, especially generalized performances, for which a history of contingency control does not provide an adequate account. Examples are provided to illustrate instances in which joint control may facilitate…

  15. Damage Parameters of Adhesive Joints with General Triaxiality, Part 2: Scarf Joint Analysis

    Microsoft Academic Search

    M. M. Abdel Wahab; I. Hilmy; I. A. Ashcroft; A. D. Crocombe

    2011-01-01

    Based on the finite element results presented in part 1 of this paper, scarf joint was chosen for further experimental investigation in order to investigate triaxiality as a function of bondline angle. At laboratory scale, scarf joints can be manufactured relatively easy due to their simple geometry. In part 2 of this paper, scarf joints as well as additional jig\\/fixture

  16. Joint Attention in Autism: Teaching Smiling Coordinated with Gaze to Respond to Joint Attention Bids

    ERIC Educational Resources Information Center

    Krstovska-Guerrero, Ivana; Jones, Emily A.

    2013-01-01

    Children with autism demonstrate early deficits in joint attention and expressions of affect. Interventions to teach joint attention have addressed gaze behavior, gestures, and vocalizations, but have not specifically taught an expression of positive affect such as smiling that tends to occur during joint attention interactions. Intervention was…

  17. Composite Materials

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Langley Research Center researchers invented an advanced polymer, a chemical compound formed by uniting many small molecules to create a complex molecule with different chemical properties. The material is a thermoplastic polyimide that resists solvents. Other polymers of this generic type are soluble in solvents, thus cannot be used where solvents are present. High Technology Services (HTS), Inc. licensed technology and is engaged in development and manufacture of high performance plastics, resins and composite materials. Techimer Materials Division is using technology for composite matrix resins that offer heat resistance and protection from radiation, electrical and chemical degradation. Applications of new polymer include molding resins, adhesives and matrix resins for fiber reinforced composites.

  18. Chord, Tie Bar & Crossbracing Joint Detail in Plan; Crossbracing ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Chord, Tie Bar & Crossbracing Joint Detail in Plan; Crossbracing Center Joint Detail in Plan; Chord Joining Detail in Plan & Elevation; Chord, Panel Post, Tie Bar, & Diagonal Brace Joint Detail; Crossbracing Center Joint Detail in Section; Chord, Panel Post, Tie Bar & Horizontal Brace Joint Detail - Narrows Bridge, Spanning Sugar Creek at Old County Road 280 East, Marshall, Parke County, IN

  19. Performance of Dowel-Welded Wood Furniture Linear Joints

    Microsoft Academic Search

    C. Segovia; A. Pizzi

    2009-01-01

    Comparison of three types of furniture joints such as scarf joints, step butt joints and dovetail joints held together either by one or two welded dowels, glued dowels and steel nails showed that the dowels always gave better shear strength and greater stiffness than the steel nails. The results of welded dowels and glued dowel joints were found to be

  20. Seawater Composition

    NSDL National Science Digital Library

    This reference discusses the composition and chemistry of seawater, and how they affect organisms in the sea. Topics include salinity, temperature, density, dissolved gases, dissolved nutrients, and pH.

  1. Prime & Composites

    NSDL National Science Digital Library

    MHamblin

    2010-10-26

    Students will review the divisibility rules and learn how a prime number differs from a composite number Let's first review the Sieve of Erasthenes with a 100's chart. sieve of Erasthenes Now let's review the divisibility rules. divisibility tests What is a prime number? A prime number is a whole number with exactly two factors. prime number interactive Composite numbers are whole numbers with more than two factors. Have a pencil and paper ready to ...

  2. Composite Flowers

    NSDL National Science Digital Library

    Conrad, Jim

    This site, part of Jim Conrad's Backyard Nature Plant web page, discusses this very large family of plants, which includes the sunflower, dandelion, and chrysanthemum. Here you will find information about the composite family's flower structure and the three kinds of composite flowers: ray only, disk only, and ray and disk. There is also a section on how to analyze disk and ray flower structures.

  3. Hydride compositions

    DOEpatents

    Lee, Myung, W.

    1994-01-01

    Disclosed are a composition for use in storing hydrogen and a method for making the composition. The composition comprises a mixture of two or more hydrides, each hydride having a different series of hydrogen sorption isotherms that contribute to the overall isotherms of the mixture. The hydrides are chosen so that the isotherms of the mixture have regions wherein the H equilibrium pressure increases with increasing hydrogen, preferably linearly. The isotherms of the mixture can be adjusted by selecting hydrides with different isotherms and by varying the amounts of the individual hydrides, or both. Preferably, the mixture is made up of hydrides that have isotherms with substantially flat plateaus and in nearly equimolar amounts. The composition is activated by degassing, exposing to H, and then heating below the softening temperature of any of the constituents. When the composition is used to store hydrogen, its hydrogen content can be found simply by measuring P{sub H}{sub 2} and determining H/M from the isothermic function of the composition.

  4. An analytical algorithm with minimum joint velocity jump for redundant robots in the presence of locked-joint failures

    Microsoft Academic Search

    Zhao Jing; Li Qian

    2008-01-01

    The joint velocity jump for redundant robots in the presence of locked-joint failures is discussed in this paper. First, the analytical formula of the optimal joint velocity with minimum jump is derived, and its specific expressions for both all joint failure and certain single joint failure are presented. Then, the jump difference between the minimum jump solution and the least-norm

  5. Keeping international joint ventures stable and profitable

    Microsoft Academic Search

    Paul W. Beamish; Andrew C. Inkpen

    1995-01-01

    If international joint ventures are inherently unstable organizational forms, as researchers and managers have suggested, why do some ventures survive and prosper for many years? This article argues that foreign partners' knowledge of the local economic, political, and cultural environments is a critical factor in the stability of international joint ventures. When the foreign partner is no longer satisfied with

  6. Navstar Global Positioning System Joint Program Office

    NSDL National Science Digital Library

    Navstar Global Positioning System Joint Program Office

    The Navstar Global Positioning System Joint Program Office site provides links to Navstar and GPS, the Joint Program Office, user equipment, space segment, control segment, CSEL Program Office, acquisition logistics, contacts, resources, GPS program library, configuration management, system engineering, user equipment sustainment, and pseudo random noise requests.

  7. Joint Occupancy: Profiles of Significant Schools.

    ERIC Educational Resources Information Center

    Clinchy, Evans

    The concept of schools that pay for themselves by sharing facilities with other occupants is known variously as joint occupancy or mixed or multiple use of land and buildings. A financial saving is the obvious advantage of combining schools with housing, commercial space (retail or office), or community services and offices. In addition, joint

  8. The Role of Rehearsal in Joint Control

    ERIC Educational Resources Information Center

    Gutierrez, Rick D.

    2006-01-01

    Behavior analysts have offered accounts of the behavior involved in matching to sample and delayed matching to sample. But until recently have not offered a behavioral analysis of generalized matching-to-sample. The concept of joint control, however, seems especially suited to such an analysis The present study used a joint-control procedure to…

  9. CRITICAL POINT ANALYSIS OF JOINT DIAGONALIZATION CRITERIA

    Microsoft Academic Search

    Gen Hori; Jonathan H. Manton

    2003-01-01

    The stability and sensitivity of joint diagonalization criteria are analyzed using the Hessian of the criteria at their critical points. The sensitivity of some known joint diagonalization criteria is shown to be weak when they are applied to the matrices with closely placed eigenvalues. In such a situation, a large deviation in the diagonalizer cause a slight change in the

  10. Rolling-Convolute Joint For Pressurized Glove

    NASA Technical Reports Server (NTRS)

    Kosmo, Joseph J.; Bassick, John W.

    1994-01-01

    Rolling-convolute metacarpal/finger joint enhances mobility and flexibility of pressurized glove. Intended for use in space suit to increase dexterity and decrease wearer's fatigue. Also useful in diving suits and other pressurized protective garments. Two ring elements plus bladder constitute rolling-convolute joint balancing torques caused by internal pressurization of glove. Provides comfortable grasp of various pieces of equipment.

  11. High temperature ceramic/metal joint structure

    DOEpatents

    Boyd, Gary L. (Tempe, AZ)

    1991-01-01

    A high temperature turbine engine includes a hybrid ceramic/metallic rotor member having ceramic/metal joint structure. The disclosed joint is able to endure higher temperatures than previously possible, and aids in controlling heat transfer in the rotor member.

  12. Tracking of Human Body Joints using Anthropometry

    Microsoft Academic Search

    Alexei Gritai; Mubarak Shah

    2006-01-01

    We propose a novel approach for tracking of human joints based on anthropometric constraints. A human is modeled as a pictorial structure consisting of body landmarks (joints) and corresponding links between them. Anthropometric con- straints relate the landmarks of two persons if they are in the same posture. Given a test video, where an actor performs the same action as

  13. Stress Relaxation Processes in Wire Wrapped Joints

    Microsoft Academic Search

    P. Sollars; IAN H. CORBY

    1975-01-01

    A standard system of determining stress relaxation behavior in wrapped joints has been developed. The system uses extended length wrapped terminals with i00 turns of wire and monitors the elastic stress reduction in terms of the relaxation of axial twist in the terminal by means of an optical magnification technique. The effect of various joint parameters on stress relaxation behavior

  14. Joint Minorities Development Program (JMDP). Final Report.

    ERIC Educational Resources Information Center

    Organizing and Supportive Agency, Inc., Ithaca, NY.

    The Joint Minorities Development Program (JMDP) was a joint enterprise of Organizing and Supportive Agency, Inc. (OSA) and Human Interest Regarding Employment/Minorities Action Coalition (HIRE/MAC) to train black construction workers and organize them into a self-supportive construction cooperative. JMDP evolved in three stages. The first phase…

  15. A joint university library: vision and reality

    Microsoft Academic Search

    Christina Flemming

    2012-01-01

    Purpose – The purpose of this paper is to analyse a Finnish model of cooperation between universities – a joint university library. Design\\/methodology\\/approach – The paper is a case study. The vision for the joint university library Tritonia, the reality when the libraries of three universities merged in 2001 and the new merging in 2010, when two more universities joined

  16. The Joint Airborne Network Services Suite

    Microsoft Academic Search

    R. Trafton; S. V. Pizzi

    2006-01-01

    In this paper we present an approach for enabling the formation of a Joint Service, heterogeneous Airborne Network. Central to this approach will be the definition of a Joint Airborne Network Services Suite (JANSS). The JANSS will consist of a common set of integrated features and functions that can be implemented on all airborne platforms to enable those platforms to

  17. Joint Involvement Associated with Inflammatory Bowel Disease

    Microsoft Academic Search

    M. De Vos

    2009-01-01

    Joint involvement associated with inflammatory bowel disease (IBD) belongs to the concept of spondyloarthritis (SpA) and includes two types of arthritis: a peripheral arthritis characterized by the presence of pauciarticular asymmetrical arthritis affecting preferentially joints of lower extremities and an axial arthropathy including inflammatory back pain, sacroiliitis and ankylosing spondylitis (AS). Treatment of arthritis includes a short-term use of NSAIDs

  18. Environmental research joint ventures among manufactures

    Microsoft Academic Search

    John T. Scott

    1996-01-01

    This paper explores the reasons that firms form research joint ventures by focusing on a particular type of venture — namely, ventures that are developing new processes to reduce toxic air emissions. The legislative expression of government concern and intent to develop regulations for toxic chemicals prompts firms to join forces in joint ventures that address the problems posed by

  19. JOINT CONFERENCE SOUTHERN ASSOCIATION FOR CANADIAN STUDIES

    E-print Network

    Duchowski, Andrew T.

    JOINT CONFERENCE SOUTHERN ASSOCIATION FOR CANADIAN STUDIES ASSOCIATION OF QUEBEC STUDIES KENNESAW and the Association of Quebec Studies will be holding a joint conference at Kennesaw State University on April 13-14, 2012. This conference will be co-sponsored by The Clemson Canada Center at Clemson University

  20. Techniques and tests for measuring joint intensity

    Microsoft Academic Search

    1979-01-01

    Anomalous intense jointing has been cited as a reason for gas production from fractured shales, coal mine roof falls, some construction problems, and increased water-well yields. The Parsons lineament in West Virginia, was chosen to develop and test field and analytical methods for measuring joint intensity. Rocks of the Middle and Upper Devonian Chemung Group and Catskill Formation, and the

  1. Dynamic joint forces during knee isokinetic exercise

    Microsoft Academic Search

    Kenton R. Kaufman; Kai-Nan An; William J. Litchy; Bernard F. Morrey; Edmund Y. S. Chao

    1991-01-01

    This study analyzed forces in the tibiofemoral and pa tellofemoral joints during isokinetic exercise using an analytical biomechanical model. The results show that isokinetic exercise can produce large loads on these joints, especially during extension exercises. The tibio femoral compressive force (4.0 body weight) is approx imately equal to that obtained during walking but it occurs at 55° of knee

  2. Suspending and Reinstating Joint Activities with Dialogue

    ERIC Educational Resources Information Center

    Chevalley, Eric; Bangerter, Adrian

    2010-01-01

    Interruptions are common in joint activities like conversations. Typically, interrupted participants suspend the activity, address the interruption, and then reinstate the activity. In conversation, people jointly commit to interact and to talk about a topic, establishing these commitments sequentially. When a commitment is suspended, face is…

  3. Turin, May 2013 Swarm Joint Open Lab

    E-print Network

    Fagnani, Fabio

    .borra@polito.it #12;Turin, May 2013 Swarm Joint Open Lab Thesis proposal ________ Title Distributed optimization to obtain distributed algorithms able to perform optimal ECS, where each agent only needs local informationTurin, May 2013 Swarm Joint Open Lab Thesis proposal ________ Title Ottimizzazione distribuita per

  4. Complications Related to Metal-on-Metal Articulation in Trapeziometacarpal Joint Total Joint Arthroplasty

    PubMed Central

    Frølich, Christina; Hansen, Torben Bæk

    2015-01-01

    Adverse reactions to metal-on-metal (MoM) prostheses are well known from total hip joint resurfacing arthroplasty with elevated serum chrome or cobalt, pain and pseudo tumor formation. It may, however, also be seen after total joint replacement of the trapeziometacarpal joint using MoM articulation, and we present two cases of failure of MoM prostheses due to elevated metal-serum levels in one case and pseudo tumor formation in another case. Furthermore, we suggest a diagnostic algorithm for joint pain after MoM trapeziometacarpal joint replacement based on published experiences from MoM hip prostheses and adverse reactions to metal. PMID:26020592

  5. Complications Related to Metal-on-Metal Articulation in Trapeziometacarpal Joint Total Joint Arthroplasty.

    PubMed

    Frølich, Christina; Hansen, Torben Bæk

    2015-01-01

    Adverse reactions to metal-on-metal (MoM) prostheses are well known from total hip joint resurfacing arthroplasty with elevated serum chrome or cobalt, pain and pseudo tumor formation. It may, however, also be seen after total joint replacement of the trapeziometacarpal joint using MoM articulation, and we present two cases of failure of MoM prostheses due to elevated metal-serum levels in one case and pseudo tumor formation in another case. Furthermore, we suggest a diagnostic algorithm for joint pain after MoM trapeziometacarpal joint replacement based on published experiences from MoM hip prostheses and adverse reactions to metal. PMID:26020592

  6. [Arthrography of the temporomandibular joint].

    PubMed

    Coquel, P; Lepoutre, F; Dupas, P H; Rousie, D; Donazzan, M

    1990-01-01

    In 1989, opaque contrast arthrography of temporomandibular joint is still seldom used. A brief historical review of the procedure is presented here, and the technique of puncturing the menisco-condylar and menisco-temporal compartments is discussed. The value of injecting opaque contrast material into the lower compartment and carrying out kinetic and tomographic studies as well as bilateral examinations is stressed. Normal aspects are described with their variants, as well as pathological ones (reducible and non-reducible luxations, perforations, distension of the bilaminar zone, adhesions, etc.). Both the place of arthrography in relation to other investigations (TDM, IRM) and its indications for visualization of menisco-condylar problems are discussed. PMID:2309081

  7. Pressure-actuated joint system

    NASA Technical Reports Server (NTRS)

    McGuire, John R. (Inventor)

    2004-01-01

    A pressure vessel is provided that includes first and second case segments mated with one another. First and second annular rubber layers are disposed inboard of the first and second case segments, respectively. The second annular rubber layer has a slot extending from the radial inner surface across a portion of its thickness to define a main body portion and a flexible portion. The flexible portion has an interfacing surface portion abutting against an interfacing surface portion of the first annular rubber layer to follow movement of the first annular rubber layer during operation of the pressure vessel. The slot receives pressurized gas and establishes a pressure-actuated joint between the interfacing surface portions. At least one of the interfacing surface portions has a plurality of enclosed and sealed recesses formed therein.

  8. Joint Committee on Atomic Energy

    NSDL National Science Digital Library

    From 1946 to 1977, the Joint Committee on Atomic Energy (JAEC) was responsible for making "continuing studies of the activities of the Atomic Energy Commission and of problems relating to the development, use, and control of atomic energy." Over three decades, the Committee looked into peacetime uses of atomic energy, international agreements regarding atomic energy, and various mutual defense agreements. The good people at the Stanford University Libraries & Academic Information Resources (SULAIR) have created this text archive of over 144,000 pages of source materials from the hearings of this committee. Visitors may wish to start with the "About the Collection" area, as it provides a bit more information on the scope of the materials here. After this, visitors are welcome to perform a simple search across the collection, or they may also wish to browse around at their leisure. The site is rounded out by a list of additional sites and resources.

  9. Phosphorescent compositions, methods of making the compositions, and methods of using the compositions

    DOEpatents

    Jia, Weiyi; Wang, Xiaojun; Yen, William; Yen, Laurel C.; Jia, George D.

    2012-12-04

    Compositions, methods of making compositions, materials including compositions, crayons including compositions, paint including compositions, ink including compositions, waxes including compositions, polymers including compositions, vesicles including the compositions, methods of making each, and the like are disclosed.

  10. Phosphorescent compositions, methods of making the compositions, and methods of using the compositions

    DOEpatents

    Jia, Weiyi; Wang, Xiaojun; Jia, George D.; Lewis, Linda; Yen, Laurel C.

    2014-06-24

    Compositions, methods of making compositions, materials including compositions, crayons including compositions, paint including compositions, ink including compositions, waxes including compositions, polymers including compositions, vesicles including the compositions, methods of making each, and the like are disclosed.

  11. Temporomandibular joint involvement in ankylosing spondylitis

    PubMed Central

    Arora, Pallak; Amarnath, Janardhan; Ravindra, Setru Veerabhadrappa; Rallan, Mandeep

    2013-01-01

    Frequency of temporomandibular joint (TMJ) involvement in patients with ankylosing spondylitis (AS) has varied from 4% to 35%. It is more common in men and produces generalised stiffness in involved joints. Clinician should be suspicious of AS when a patient reports with painful restricted movements of joint, neck or back and with no trauma history. Conventional radiographic methods have allowed the demonstration of TMJ abnormalities in patients with AS, but CT is necessary to establish joint space relations and bony morphology. We describe a case of severe AS with TMJ involvement in a 40-year-old female patient and demonstrated TMJ changes on CT. A CT was able to demonstrate articular cartilage changes, disc- and joint abnormalities. Thus, if conventional radiographs in a symptomatic patient with rheumatic diseases are unable to demonstrate changes, CT can provide valuable additional information of the changes in the TMJ. PMID:23645650

  12. Robust Joining and Assembly of Ceramic Matrix Composites for High Temperature Applications

    NASA Technical Reports Server (NTRS)

    Singh, Mrityunjay

    2003-01-01

    Advanced ceramic matrix composites (CMCs) are under active consideration for use in a wide variety of high temperature applications within the aerospace, energy, and nuclear industries. The engineering designs of CMC components require fabrication and manufacturing of large and complex shaped parts of various thicknesses. In many instances, it is more economical to build up complex shapes by joining simple geometrical shapes. Thus, joining and attachment have been recognized as enabling technologies for successful utilization of ceramic components in various demanding applications. In this presentation, various challenges and opportunities in design, fabrication, and testing of high temperature joints in ceramic matrix composites will be presented. A wide variety of ceramic composites, in different shapes and sizes, have been joined using an affordable, robust ceramic joining technology (ARCJoinT). Microstructure and mechanical properties of joints in melt infiltrated and CVI Sic matrix composites will be reported. Various joint design philosophies and design issues in joining of composites will be discussed.

  13. Electronic hidden solder joint geometry characterization

    NASA Astrophysics Data System (ADS)

    Hsieh, Sheng-Jen

    2009-05-01

    To reduce the size of electronic equipment, multi-layer printed circuit board structures have become popular in recent years. As a result, the inspection of hidden solder joints between layers of boards has become increasingly difficult. Xray machines have been used for ball grid array (BGA) and hidden solder joint inspection; however, the equipment is costly and the inspection process is time consuming. In this paper, we investigate an active thermography approach to probing solder joint geometry. A set of boards having the same number of solder joints and amount of solder paste (0.061 g) was fabricated. Each solder joint had a different geometry. A semi-automated system was built to heat and then transfer each board to a chamber where an infrared camera was used to scan the board as it was cooling down. Two-thirds of the data set was used for model development and one-third was used for model evaluation. Both artificial neural network (ANN) and binary logistic regression models were constructed. Results suggest that solder joints with more surface area cool much faster than those with less surface area. In addition, both modeling approaches are consistent in predicting solder geometry; ANN had 85% accuracy and the regression model had 80%. This approach can potentially be used to test for cold solder joints prior to BGA assembly, since cold solder joints may have air gaps between the joint and the board and air is a poor heat conductor. Therefore, a cold solder joint may have a slower cooling rate than a normal one.

  14. Chord, Horizontal Tie Bar & Crossbracing Joint Details; Crossbracing Center ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Chord, Horizontal Tie Bar & Crossbracing Joint Details; Crossbracing Center Joint Detail; Chord, Panel Posts, Braces & Counterbrace Joint Detail - Brownsville Covered Bridge, Spanning East Fork Whitewater River (moved to Eagle Creek Park, Indianapolis), Brownsville, Union County, IN

  15. Chord Splicing & Joining Detail; Chord & CrossBracing Joint Details; ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Chord Splicing & Joining Detail; Chord & Cross-Bracing Joint Details; Cross Bracing Center Joint Detail; Chord & Diagonal Joint Detail - Vermont Covered Bridge, Highland Park, spanning Kokomo Creek at West end of Deffenbaugh Street (moved to), Kokomo, Howard County, IN

  16. 21 CFR 872.3940 - Total temporomandibular joint prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...Total temporomandibular joint prosthesis. 872.3940 Section 872...CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices...Total temporomandibular joint prosthesis. (a) Identification. A total temporomandibular joint prosthesis is a device that is...

  17. 21 CFR 872.3940 - Total temporomandibular joint prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...Total temporomandibular joint prosthesis. 872.3940 Section 872...CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices...Total temporomandibular joint prosthesis. (a) Identification. A total temporomandibular joint prosthesis is a device that is...

  18. 21 CFR 872.3940 - Total temporomandibular joint prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...Total temporomandibular joint prosthesis. 872.3940 Section 872...CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices...Total temporomandibular joint prosthesis. (a) Identification. A total temporomandibular joint prosthesis is a device that is...

  19. 21 CFR 872.3940 - Total temporomandibular joint prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...Total temporomandibular joint prosthesis. 872.3940 Section 872...CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices...Total temporomandibular joint prosthesis. (a) Identification. A total temporomandibular joint prosthesis is a device that is...

  20. 44 CFR 150.5 - Joint Public Safety Awards Board.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 false Joint Public Safety Awards Board. 150.5 Section 150.5 ...PREVENTION AND CONTROL PUBLIC SAFETY AWARDS TO PUBLIC SAFETY OFFICERS § 150.5 Joint Public Safety Awards Board. (a) A Joint Public...

  1. 21 CFR 888.3720 - Toe joint polymer constrained prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 2013-04-01 false Toe joint polymer constrained prosthesis. 888.3720...Prosthetic Devices § 888.3720 Toe joint polymer constrained prosthesis. (a) Identification. A toe joint polymer constrained prosthesis is a...

  2. The Cost of Jointness and How to Manage It

    E-print Network

    Dwyer, Morgan

    Although joint programs are typically formed to reduce costs, recent studies have suggested that joint programs experience larger cost growth than non-joint programs. To explain this phenomenon, we present a model that ...

  3. Exercises in radiological diagnosis of the cervicooccipital joint

    SciTech Connect

    Wackenheim, A.

    1985-01-01

    This book discusses the diagnostic radiology of joints of neck and skull. The contents are: Atlanto-occipital joint-Radiography Problems, exercises, etc.; and Atlanto-occipital joint-Radiography-Case studies.

  4. 14 CFR 13.217 - Joint procedural or discovery schedule.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 2012-01-01 false Joint procedural or discovery schedule. 13...FAA Civil Penalty Actions § 13.217 Joint procedural or discovery schedule. ...schedule. If the parties agree to a joint procedural or discovery schedule,...

  5. 14 CFR 406.139 - Joint procedural or discovery schedule.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 2010-01-01 false Joint procedural or discovery schedule. 406...Transportation Adjudications § 406.139 Joint procedural or discovery schedule. ...schedule. If the parties agree to a joint procedural or discovery schedule,...

  6. 12 CFR 330.9 - Joint ownership accounts.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 2013-01-01 false Joint ownership accounts. 330.9 Section...DEPOSIT INSURANCE COVERAGE § 330.9 Joint ownership accounts. (a) Separate insurance coverage. Qualifying joint accounts, whether owned as...

  7. 14 CFR 13.217 - Joint procedural or discovery schedule.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 2013-01-01 false Joint procedural or discovery schedule. 13...FAA Civil Penalty Actions § 13.217 Joint procedural or discovery schedule. ...schedule. If the parties agree to a joint procedural or discovery schedule,...

  8. 49 CFR 1503.627 - Joint procedural or discovery schedule.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Joint procedural or discovery schedule. 1503...Civil Penalty Actions § 1503.627 Joint procedural or discovery schedule. ...schedule. If the parties agree to a joint procedural or discovery schedule,...

  9. 49 CFR 1503.627 - Joint procedural or discovery schedule.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Joint procedural or discovery schedule. 1503...Civil Penalty Actions § 1503.627 Joint procedural or discovery schedule. ...schedule. If the parties agree to a joint procedural or discovery schedule,...

  10. 49 CFR 240.229 - Requirements for joint operations territory.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 2012-10-01 false Requirements for joint operations territory. 240.229 Section...Certification Process § 240.229 Requirements for joint operations territory. (a) Except for minimal joint operations provided for in paragraph...

  11. 50 CFR 452.09 - Consolidated and joint proceedings.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 false Consolidated and joint proceedings. 452.09 Section 452.09 Wildlife and Fisheries JOINT REGULATIONS (UNITED STATES FISH...SECRETARY § 452.09 Consolidated and joint proceedings. (a) When the...

  12. 14 CFR 406.139 - Joint procedural or discovery schedule.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 2014-01-01 false Joint procedural or discovery schedule. 406...Transportation Adjudications § 406.139 Joint procedural or discovery schedule. ...schedule. If the parties agree to a joint procedural or discovery schedule,...

  13. 14 CFR 13.217 - Joint procedural or discovery schedule.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 2014-01-01 false Joint procedural or discovery schedule. 13...FAA Civil Penalty Actions § 13.217 Joint procedural or discovery schedule. ...schedule. If the parties agree to a joint procedural or discovery schedule,...

  14. 77 FR 69619 - Draft Recommendations of Joint Outreach Team

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-20

    ...Administration Draft Recommendations of Joint Outreach Team AGENCY: Western Area Power...draft recommendations of Western/DOE Joint Outreach Team...draft recommendations of the Western/DOE Joint Outreach Team (JOT) for review and...

  15. 14 CFR 406.139 - Joint procedural or discovery schedule.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 2013-01-01 false Joint procedural or discovery schedule. 406...Transportation Adjudications § 406.139 Joint procedural or discovery schedule. ...schedule. If the parties agree to a joint procedural or discovery schedule,...

  16. 50 CFR 452.09 - Consolidated and joint proceedings.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 false Consolidated and joint proceedings. 452.09 Section 452.09 Wildlife and Fisheries JOINT REGULATIONS (UNITED STATES FISH...SECRETARY § 452.09 Consolidated and joint proceedings. (a) When the...

  17. 12 CFR 330.9 - Joint ownership accounts.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 2010-01-01 false Joint ownership accounts. 330.9 Section...DEPOSIT INSURANCE COVERAGE § 330.9 Joint ownership accounts. (a) Separate insurance coverage. Qualifying joint accounts, whether owned as...

  18. 49 CFR 240.229 - Requirements for joint operations territory.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 2014-10-01 false Requirements for joint operations territory. 240.229 Section...Certification Process § 240.229 Requirements for joint operations territory. (a) Except for minimal joint operations provided for in paragraph...

  19. 49 CFR 1503.627 - Joint procedural or discovery schedule.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Joint procedural or discovery schedule. 1503...Civil Penalty Actions § 1503.627 Joint procedural or discovery schedule. ...schedule. If the parties agree to a joint procedural or discovery schedule,...

  20. 14 CFR 13.217 - Joint procedural or discovery schedule.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 2010-01-01 false Joint procedural or discovery schedule. 13...FAA Civil Penalty Actions § 13.217 Joint procedural or discovery schedule. ...schedule. If the parties agree to a joint procedural or discovery schedule,...