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1

Nonlinear Analysis of Bonded Composite Single-LAP Joints  

NASA Technical Reports Server (NTRS)

This study presents a semi-analytical solution method to analyze the geometrically nonlinear response of bonded composite single-lap joints with tapered adherend edges under uniaxial tension. The solution method provides the transverse shear and normal stresses in the adhesive and in-plane stress resultants and bending moments in the adherends. The method utilizes the principle of virtual work in conjunction with von Karman s nonlinear plate theory to model the adherends and the shear lag model to represent the kinematics of the thin adhesive layer between the adherends. Furthermore, the method accounts for the bilinear elastic material behavior of the adhesive while maintaining a linear stress-strain relationship in the adherends. In order to account for the stiffness changes due to thickness variation of the adherends along the tapered edges, their in-plane and bending stiffness matrices are varied as a function of thickness along the tapered region. The combination of these complexities results in a system of nonlinear governing equilibrium equations. This approach represents a computationally efficient alternative to finite element method. Comparisons are made with corresponding results obtained from finite-element analysis. The results confirm the validity of the solution method. The numerical results present the effects of taper angle, adherend overlap length, and the bilinear adhesive material on the stress fields in the adherends, as well as the adhesive, of a single-lap joint

Oterkus, E.; Barut, A.; Madenci, E.; Smeltzer, S. S.; Ambur, D. R.

2004-01-01

2

Analysis of single lap adhesive composite joints with delaminated adherends  

Microsoft Academic Search

Polymer composites have high potential for applications in repair of aerospace structures. Adhesively bonded composite patches minimize balance and clearance problems on control surfaces and can be readily formed to complex aircraft contours. Delamination in composites can be detrimental to joint performance and durability and should be accounted for in joint design. In this work, a simple engineering model is

Minghao Qin; Yuris A. Dzenis

2003-01-01

3

Effect of stitching on the strength of bonded composite single lap joints  

NASA Technical Reports Server (NTRS)

An experimental investigation has been conducted to determine the effect of stitching on the static and fatigue failure load of bonded composite single lap joints. The variables considered in the static tests included adherend thickness, overlap length, stitch spacing, and number of rows of stitches. A limited fatigue program was conducted for one configuration to compare the fatigue life of stitched and unstitched joints. Up to a 38 percent improvement in static failure load and an order of magnitude increase in fatigue life compared with unstiffened results are obtained by a single row of stitches near the end of the overlap. Additional rows of stitching or different stitch spacing has little effect on static joint failure load. Thicker adherends and larger overlap length result in larger improvements in static failure load with stitching. Further research is needed to refine the stitching process in order to obtain the maximum improvements in joint failure load.

Sawyer, J. W.

1983-01-01

4

Shear Strength of Single Lap Joint Aluminium-Thermoplastic Natural Rubber (Al-TPNR) Laminated Composite  

NASA Astrophysics Data System (ADS)

In this work, we studied the effect of surface treatment on the aluminium surface and a coupling agent to improve adhesion between aluminium with organic polymer. Thermoplastic natural rubber (TPNR) matrix was prepared by melt blending of natural rubber (NR), liquid natural rubber (LNR) compatibilizer, linear low density polyethylene (LLDPE) and polyethylene grafted maleic anhydride (PE-g-MAH). The PEgMAH concentration used was varied from 0% - 25%. In addition, the aluminium surface was pre-treated with 3-glycidoxy propyl trimethoxy silane (3-GPS) to enhance the mechanical properties of laminated composite. It was found that the shear strength of single lap joint Al-TPNR laminated composite showing an increasing trend as a function of PE-g-MAH contents for the 3-GPS surface treated aluminium. Moreover, the scanning electron microscope (SEM) revealed that the strength improvement was associated with the chemical state of the compound involved.

Muzakkar, M. Z.; Ahmad, S.; Yarmo, M. A.; Jalar, A.; Bijarimi, M.

2013-04-01

5

Biomimetic-inspired joining of composite with metal structures: A survey of natural joints and application to single lap joints  

NASA Astrophysics Data System (ADS)

Joining composites with metal parts leads, inevitably, to high stress concentrations because of the material property mismatch. Since joining composite to metal is required in many high performance structures, there is a need to develop a new multifunctional approach to meet this challenge. This paper uses the biomimetics approach to help develop solutions to this problem. Nature has found many ingenious ways of joining dissimilar materials and making robust attachments, alleviating potential stress concentrations. A literature survey of natural joint systems has been carried out, identifying and analysing different natural joint methods from a mechanical perspective. A taxonomy table was developed based on the different methods/functions that nature successfully uses to attach dissimilar tissues (materials). This table is used to understand common themes or approaches used in nature for different joint configurations and functionalities. One of the key characteristics that nature uses to joint dissimilar materials is a transitional zone of stiffness in the insertion site. Several biomimetic-inspired metal-to-composite (steel-to-CFRP), adhesively bonded, Single Lap Joints (SLJs) were numerically investigated using a finite element analysis. The proposed solutions offer a transitional zone of stiffness of one joint part to reduce the material stiffness mismatch at the joint. An optimisation procedure was used to identify the variation in material stiffness which minimises potential failure of the joint. It was found that the proposed biomimetic SLJs reduce the asymmetry of the stress distribution along the adhesive area.

Avgoulas, Evangelos Ioannis; Sutcliffe, Michael P. F.

2014-03-01

6

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

Microsoft Academic Search

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.

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

2011-01-01

7

Fatigue strength of a single lap joint SPR-bonded  

NASA Astrophysics Data System (ADS)

In the last years, hybrid joints, meaning with this the joints which consist in combining a traditional mechanical joint to a layer of adhesive, are gradually attracting the attention of various sectors of the construction of vehicles and transportation industries, for their better performance compared to just mechanical joints (self-piercing riveting SPR, riveting, and so on) or just to bonded joints. The paper investigates the fatigue behavior of a single lap joint self-piercing riveted (SPR) and bonded throughout fatigue tests. The considered geometric configuration allowed the use of two rivets placed longitudinally; an epoxy resin was used as adhesive. In the first part of the work static characterization of the joints was carried out through tensile tests. Then fatigue tests were made with the application of different levels of load. The fatigue curves were also obtained at the varying the distance between the two rivets in order to better assess the joint strength for a given length of overlap.

di Franco, G.; Fratini, L.; Pasta, A.

2011-05-01

8

Modified single lap joint (MSLJ) test configuration for the determination of adhesive fracture energy  

Microsoft Academic Search

In this work, a modification has been proposed to the traditional single lap joint (SLJ) configuration, to overcome the wide scatter in the fracture toughness measurement due to adhesive fillets. This modification, referred to as the Modified Single Lap Joint (MSLJ), is made by implanting end pre-cracks in the adhesive layer at the center of the bond line in a

S. B. Kumar; I. Sridhar; S. Sivashanker; Asim Bag; S. O. Osiyemi

2005-01-01

9

Bond strength for adhesive-bonded single-lap joints  

Microsoft Academic Search

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

L. Tong

1996-01-01

10

An Experimental Study of Fatigue Strength for Adhesively Bonded Tubular Single Lap Joints  

Microsoft Academic Search

In this paper, manufacturing technology of the tubular single lap adhesive joint was studied to obtain reliable and optimal joint quality. In addition, a surface preparation method and a bonding process for the joint were devised. The effect of the adhesive thickness and the adherend roughness on the fatigue strength of the joint was experimentally investigated. From experiments, it has

Dai Gil Lee; Ki Soo Kim; Yong-Taek Im

1991-01-01

11

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

Microsoft Academic Search

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

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

2003-01-01

12

The determination of dynamic strength of single lap joints using the split Hopkinson pressure bar  

Microsoft Academic Search

The current investigation focuses on the determination of the strength of adhesive-bonded single lap joints under impact with the use of a split Hopkinson pressure bar (Kolsky bar). For this, experiments were conducted at different loading rates, for identical metallic adherends bonded by a two-part epoxy adhesive. Four different types of specimens were adopted, all with a given adhesive thickness.

Oishik Sen; Srinivasan Arjun Tekalur; Clarence Jilek

2011-01-01

13

Development of a Failure Model for the Adhesively Bonded Tubular Single Lap Joint  

Microsoft Academic Search

The accurate calculation of the stresses and torque capacities of adhesively bonded joints is not possible without understanding the failure phenomena of the adhesive joints and the nonlinear behavior of the adhesive.In this paper, an adhesive failure model of the adhesively bonded tubular single lap joint with steel-steel adherends was proposed to predict the torque capacity accurately.The model incorporated the

Su Jeong Lee; Dai Gil Lee

1992-01-01

14

A critical examination of stresses in an elastic single lap joint  

NASA Technical Reports Server (NTRS)

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.

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

1979-01-01

15

A Single-Lap Joint Adhesive Bonding Optimization Method Using Gradient and Genetic Algorithms  

NASA Technical Reports Server (NTRS)

A natural process for any engineer, scientist, educator, etc. is to seek the most efficient method for accomplishing a given task. In the case of structural design, an area that has a significant impact on the structural efficiency is joint design. Unless the structure is machined from a solid block of material, the individual components which compose the overall structure must be joined together. The method for joining a structure varies depending on the applied loads, material, assembly and disassembly requirements, service life, environment, etc. Using both metallic and fiber reinforced plastic materials limits the user to two methods or a combination of these methods for joining the components into one structure. The first is mechanical fastening and the second is adhesive bonding. Mechanical fastening is by far the most popular joining technique; however, in terms of structural efficiency, adhesive bonding provides a superior joint since the load is distributed uniformly across the joint. The purpose of this paper is to develop a method for optimizing single-lap joint adhesive bonded structures using both gradient and genetic algorithms and comparing the solution process for each method. The goal of the single-lap joint optimization is to find the most efficient structure that meets the imposed requirements while still remaining as lightweight, economical, and reliable as possible. For the single-lap joint, an optimum joint is determined by minimizing the weight of the overall joint based on constraints from adhesive strengths as well as empirically derived rules. The analytical solution of the sin-le-lap joint is determined using the classical Goland-Reissner technique for case 2 type adhesive joints. Joint weight minimization is achieved using a commercially available routine, Design Optimization Tool (DOT), for the gradient solution while an author developed method is used for the genetic algorithm solution. Results illustrate the critical design variables as a function of adhesive properties and convergences of different joints based on the two optimization methods.

Smeltzer, Stanley S., III; Finckenor, Jeffrey L.

1999-01-01

16

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

SciTech Connect

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.

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

17

A two-dimensional stress analysis of single-lap adhesive joints of dissimilar adherends subjected to tensile loads  

Microsoft Academic Search

Single-lap adhesive joints of dissimilar adherends subjected to tensile loads are analyzed as a three-body contact problem using the two-dimensional theory of elasticity. In the numerical calculations, the effects of Young's modulus ratio between different adherends, the ratio of the adherend thicknesses, the ratio of the adherend lengths, and the adhesive thickness on the contact stress distributions at the interfaces

Toshiyuki Sawa; Jiemin Liu; Katsuyuki Nakano; Junnya Tanaka

2000-01-01

18

On joint strengths, peel stresses and failure modes in adhesively bonded double-strap and supported single-lap GFRP joints  

Microsoft Academic Search

This paper presents the results of an experimental investigation conducted to characterize the joint strengths, peel stresses and failure modes in adhesively bonded double-strap and supported single-lap glass fiber-reinforced polymer (GFRP) joints. The joints were composed of pultruded GFRP adherends having the same stiffness as the members that would be used in FRP bridge decks. The design parameters investigated in

H. K. Lee; S. H. Pyo; B. R. Kim

2009-01-01

19

Nd:Yag laser irradiation of single lap joints made by polyethylene and polyethylene doped by carbon nanomaterials  

NASA Astrophysics Data System (ADS)

Thermoplastic polyethylene can be welded by the transmission laser welding technique (TTLW) that exhibits some process related benefits with respect other conventional joining methods. This justifies its large use in wide fields, from the automotive to medical or domestic appliances. In this research, we studied single lap joints made by polyethylene pure and filled with carbon nanomaterials (0.2% in weight) to make the polymer laser absorbent. The joints were irradiated by a Nd:YAG laser operating at 1064 nm (first harmonic) with an intensity of 107 W/cm2 and 1 ÷ 30Hz, a maximum pulse energy of 300mJ and a laser spot of ? 1 cm2 (no focusing lens were employed). The joints were characterized by morphological analysis, mechanical shear tests and calorimetric analysis. The results suggested that the laser exposition time must be opportunely balanced in order to avoid a poor adhesion between the polymer sheets and to realized efficient joints. In particular the mechanical test showed that the laser exposition time of 40 seconds is the best conditions to obtain the highest shear strength of the joints of 140 N. After too prolonged laser exposure times, degrading phenomena starts.

Visco, A. M.; Brancato, V.; Cutroneo, M.; Torrisi, L.

2014-04-01

20

Effect of spew geometry on stresses in single lap adhesive joints  

Microsoft Academic Search

Spew is defined as the portion of adhesive that is squeezed out from the lap area and forms a bead at the lap ends as the two substrates are assembled. Spew is always present in an adhesive joint, but is usually neglected in the stress analysis of adhesively bonded joints. As known, the presence of spews can reduce peak stresses

T. P. Lang; P. K. Mallick

1998-01-01

21

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

Microsoft Academic Search

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

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

2010-01-01

22

Global-Local Finite Element Analysis of Bonded Single-Lap Joints  

NASA Technical Reports Server (NTRS)

Adhesively bonded lap joints involve dissimilar material junctions and sharp changes in geometry, possibly leading to premature failure. Although the finite element method is well suited to model the bonded lap joints, traditional finite elements are incapable of correctly resolving the stress state at junctions of dissimilar materials because of the unbounded nature of the stresses. In order to facilitate the use of bonded lap joints in future structures, this study presents a finite element technique utilizing a global (special) element coupled with traditional elements. The global element includes the singular behavior at the junction of dissimilar materials with or without traction-free surfaces.

Kilic, Bahattin; Madenci, Erdogan; Ambur, Damodar R.

2004-01-01

23

STRESS ANALYSIS OF THIN ADHESIVE BONDING DISSIMILAR ADHERENDS SINGLE LAP JOINTS  

Microsoft Academic Search

In recent years, adhesives have been widely used to bond dissimilar material members particularly in aircraft and automobile structures. If the adhesive layer is very small compared with adherends, a more refined mesh model is needed for FEA modeling. That will take a lot of CPU-time to compute solution. However, there is a method to solve the adhesive lap joints

Thongchai Fongsamootr; Charoenyut Dechwayukul

24

Analysis of adhesive bonded composite lap joints with transverse stitching  

Microsoft Academic Search

The effect of transverse stitching on the stresses in the adhesive is investigated using an adhesive sandwich model with nonlinear adhesive properties and a transverse stitching model for adhesive bonded composite single-lap and double-lap joints. Numerical results indicate that, among all stitching parameters, thread pretension and stitch density have significant effect on the peel stresses in the adhesive; increase in

L. Tong; L. K. Jain

1996-01-01

25

Monitoring of fatigue crack growth in composite adhesively bonded joints using Fiber Bragg Gratings  

Microsoft Academic Search

Optical sensors, like Fiber Bragg Gratings (FBG), can be easily embedded into composite structures, thus obtaining structures with health monitoring capabilities. In this work, fatigue crack growth in adhesively bonded joints of thick composite laminates was experimentally investigated using FBG. An array of equally spaced sensors was applied to the side of a single lap tapered joint, in order to

Andrea Bernasconi; Michele Carboni; Lorenzo Comolli

2011-01-01

26

Modelling the environmental degradation of adhesively bonded aluminium and composite joints using a CZM approach  

Microsoft Academic Search

The long-term durability of adhesively bonded aluminium, composite and dissimilar substrate joints exposed to humid environments has been investigated. Failure of the joints was modelled with a cohesive zone model (CZM) approach where the governing parameters were determined from fracture mechanics test specimens saturated in a range of humid environments. The reduction in residual strength of an aluminium single lap

C. D. M. Liljedahl; A. D. Crocombe; M. A. Wahab; I. A. Ashcroft

2007-01-01

27

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

Microsoft Academic Search

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

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

2006-01-01

28

Influence of the Adhesive, the Adherend and the Overlap on the Single Lap Shear Strength  

Microsoft Academic Search

The single lap joint is the most studied joint in the literature in terms of both theory and practice. It is easy to manufacture and the lap shear strength is a useful value for strength assessment and quality control. Simple design rules exist such as the one present in standard ASTM 1002 or in a recent paper by Adams and

Lucas F M da Silva; J E Ramos; M V Figueiredo; T R Strohaecker

29

Failure of transversely stitched RTM lap joints  

Microsoft Academic Search

An experimental evaluation has been undertaken to investigate the effect of transverse stitching on the strength of composite single-lap joints. Balanced single-lap joints were considered, and the lay-up for the adherends was (0\\/ ±45\\/90)s. Specimens were stitched with Kevlar® thread in a zigzag pattern and were manufactured by using the resin-transfer moulding (RTM) technique. Experimental results indicated that stitched joints

L. Tong; L. K. Jain; K. H. Leong; D. Kelly; I. Herszberg

1998-01-01

30

Stiffness behaviour due to fracture in adhesively bonded composite-to-aluminum joints II. Experimental  

Microsoft Academic Search

Experimental testing of composite-to-aluminum single-lap joints has been performed to verify the theoretical model proposed in Part I. Using specimens bonded with a flexible and a rigid adhesive, tests were conducted at room temperature and ?40°C. Results show that the joint stiffness is more affected by the response of the adherends to the test temperature than by the modulus of

James F. P Owens; Pearl Lee-Sullivan

2000-01-01

31

Delamination and Stitched Failure in Stitched Composite Joints.  

National Technical Information Service (NTIS)

The effect of stitches on the failure of a single lap joint configuration was determined in a combined experimental and finite element study. The experimental program was conducted to determine debond growth under static monotonic loading. The stitches we...

E. H. Glaessgen I. S. Raju C. C. Poe

1999-01-01

32

Progressive damage analysis of composite bolted joints with liquid shim layers using constant and continuous degradation models  

Microsoft Academic Search

The structural behaviour of a single-lap, single-bolt composite joint is investigated using a three-dimensional finite element model. In contrast to previous investigations the influence of a liquid shim layer, added between the two laminates, on strength and structural behaviour of the joints is investigated by virtual testing. The finite element model is validated with experimental data. The experiments point out

C. Hühne; A.-K. Zerbst; G. Kuhlmann; C. Steenbock; R. Rolfes

2010-01-01

33

Nonlinear Analysis of Bonded Composite Tubular Lap Joints  

NASA Technical Reports Server (NTRS)

The present study describes a semi-analytical solution method for predicting the geometrically nonlinear response of a bonded composite tubular single-lap joint subjected to general loading conditions. The transverse shear and normal stresses in the adhesive as well as membrane stress resultants and bending moments in the adherends are determined using this method. The method utilizes the principle of virtual work in conjunction with nonlinear thin-shell theory to model the adherends and a cylindrical shear lag model to represent the kinematics of the thin adhesive layer between the adherends. The kinematic boundary conditions are imposed by employing the Lagrange multiplier method. In the solution procedure, the displacement components for the tubular joint are approximated in terms of non-periodic and periodic B-Spline functions in the longitudinal and circumferential directions, respectively. The approach presented herein represents a rapid-solution alternative to the finite element method. The solution method was validated by comparison against a previously considered tubular single-lap joint. The steep variation of both peeling and shearing stresses near the adhesive edges was successfully captured. The applicability of the present method was also demonstrated by considering tubular bonded lap-joints subjected to pure bending and torsion.

Oterkus, E.; Madenci, E.; Smeltzer, S. S., III; Ambur, D. R.

2005-01-01

34

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

NASA Technical Reports Server (NTRS)

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.

Barclay, D. L.

1980-01-01

35

Test and analysis of Celion 3000/PMR-15, graphite/polyimide bonded composite joints: Data report  

NASA Technical Reports Server (NTRS)

Standard single lap, double lap and symmetric step lap bonded joints of Celion 3000/PMR-15 graphite/polyimide composite were evaluated. Composite to composite and composite to titanium joints were tested at 116 K (-250 F), 294 K (70 F) and 561 K (550 F). Joint parameters evaluated are lap length, adherend thickness, adherend axial stiffness, lamina stacking sequence and adherend tapering. Advanced joint concepts were examined to establish the change in performance of preformed adherends, scalloped adherends and hybrid systems. The material properties of the high temperature adhesive, designated A7F, used for bonding were established. The bonded joint tests resulted in interlaminar shear or peel failures of the composite and there were very few adhesive failures. Average test results agree with expected performance trends for the various test parameters. Results of finite element analyses and of test/analysis correlations are also presented.

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

1982-01-01

36

The Analysis of Adhesively Bonded Advanced Composite Joints Using Joint Finite Elements  

NASA Technical Reports Server (NTRS)

The design and sizing of adhesively bonded joints has always been a major bottleneck in the design of composite vehicles. Dense finite element (FE) meshes are required to capture the full behavior of a joint numerically, but these dense meshes are impractical in vehicle-scale models where a course mesh is more desirable to make quick assessments and comparisons of different joint geometries. Analytical models are often helpful in sizing, but difficulties arise in coupling these models with full-vehicle FE models. Therefore, a joint FE was created which can be used within structural FE models to make quick assessments of bonded composite joints. The shape functions of the joint FE were found by solving the governing equations for a structural model for a joint. By analytically determining the shape functions of the joint FE, the complex joint behavior can be captured with very few elements. This joint FE was modified and used to consider adhesives with functionally graded material properties 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. 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. Furthermore, the capability to model non-linear adhesive constitutive behavior with large rotations was developed, and progressive failure of the adhesive was modeled by re-meshing the joint as the adhesive fails. Results predicted using the joint FE was compared with experimental results for various joint configurations, including double cantilever beam and single lap joints.

Stapleton, Scott E.; Waas, Anthony M.

2012-01-01

37

Optimal tubular adhesive-bonded lap joint of the carbon fiber epoxy composite shaft  

NASA Astrophysics Data System (ADS)

The effects of the adhesive thickness and the adherend surface roughness on the fatigue strength of a tubular adhesive-bonded single lap joint were investigated using fatigue test specimens whose adherends were made of S45C carbon steel. Results of fatigue tests showed that the optimal arithmetic surface roughness of the adherends is about 2 microns and the optimal adhesive thickness is about 0.15 mm. Using these values, the prototype torsional adhesive joints were manufactured for power transmission shafts of an automotive vehicle or a small helicopter, and static tests under torque were performed on a single-lap joint, a single-lap joint with scarf, a double-lap joint, and a double-lap joint with scarf. It was found that the double-lap joint was superior among the joints, in terms of torque capacity and manufacturing cost.

Kim, Ki S.; Kim, Won T.; Lee, Dai G.; Jun, Eui J.

38

Analytical and Experimental Studies of the Debonding of Stitched and Unstitched Composite Joints  

Microsoft Academic Search

The effect of stitches on the failure of a single lap joint configuration was determined in a combined experimental and finite element study. The experimental program was conducted to determine debond growth under static monotonic loading. The stitches were shown to delay the initiation of the debond and provide load transfer after total debonding of the lap joint. The experimentally

E. H. Glaessgen; I. S. Raju; C. C. Poe Jr

2002-01-01

39

Assessment of adhesively bonded joints subjected to surface damage by paint removal  

Microsoft Academic Search

Purpose – To provide a basis for making assessment of the safety of adhesively bonded joints after they have been de-painted by a dry abrasive method or a wet chemical method. Design\\/methodology\\/approach – Stress analysis by a finite element method has been conducted for metal\\/composite and composite\\/composite joints in a single lap configuration. The effects of degradation of composite and

Shantanu C. Prabhune; Ramesh Talreja

2007-01-01

40

Mechanical Properties of Nanoclay Reinforced Epoxy Adhesive Bonded Joints Made with Composite Materials  

Microsoft Academic Search

This study was intended to characterize the mechanical properties of nanoclay filled epoxy adhesive single lap joints under both static (tensile) and dynamic (impact) loadings. The nanoclay contents were 1, 3 and 5 wt% of epoxy resin (Araldite LY5052). The nanoclay particles were dispersed in the epoxy resin by a stirring device and then the mixture of resin and clay

S. M. R. Khalili; M. Tavakolian; A. Sarabi

2010-01-01

41

Optimal tubular adhesive-bonded lap joint of the carbon fiber epoxy composite shaft  

Microsoft Academic Search

The effects of the adhesive thickness and the adherend surface roughness on the fatigue strength of a tubular adhesive-bonded single lap joint were investigated using fatigue test specimens whose adherends were made of S45C carbon steel. Results of fatigue tests showed that the optimal arithmetic surface roughness of the adherends is about 2 microns and the optimal adhesive thickness is

Ki S. Kim; Won T. Kim; Dai G. Lee; Eui J. Jun

1992-01-01

42

Predicting the Fatigue Life of Adhesively-Bonded Joints  

Microsoft Academic Search

The fatigue behaviour of adhesively-bonded joints, which consisted of an epoxy-film adhesive bonding fibre-composite substrates, has been studied. Using a double-cantilever beam specimen, the rate of crack growth per cycle has been measured as a function of the maximum strain-energy release rate, Gmax. These data have then been modelled, and used to predict the fatigue lifetime of bonded single-lap joints.

A. J. Kinloch; S. O. Osiyemi

1993-01-01

43

Experimental–numerical studies of transverse impact response of adhesively bonded lap joints in composite structures  

Microsoft Academic Search

Adhesively bonded joints in structures are subjected to in-plane and out-of-plane loads. In this work, the response of a balanced, single-lap adhesively bonded joint to a transverse normal impact load was investigated by means of LS-DYNA 3D finite element software and supporting experiments. The finite element model is based on cohesive failure in the bonded joint when the ultimate failure

Uday K. Vaidya; Abhay R. S. Gautam; Mahesh Hosur; Piyush Dutta

2006-01-01

44

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

NASA Astrophysics Data System (ADS)

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.

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

45

Preloaded Composite-Strut/End-Fitting Joint  

NASA Technical Reports Server (NTRS)

Proposed structural joint between composite strut and metal end fitting strong and light in weight. Joint configured to distribute stresses fairly uniformly, with little interlaminar stress. Composite-strut/metal-fitting joint built up integrally with strut in layup process. Joint remains tight under reversals of loads and changes in temperature.

Monitor, Dean S.

1990-01-01

46

Analysis of multifastener composite joints  

NASA Technical Reports Server (NTRS)

A new numerical procedure for determining load proportioning in multiple-hole mechanical joints in composite plates is presented. The joints are loaded in double lap fashion in tension with pins through the holes. The commercial finite-element program ABAQUS is used to predict the load proportioning among holes using two independent plane stress finite-element models, one representing the composite inner lap and one representing the two steel outer laps, interacting through rigid circular surfaces. The circular surfaces effectively represent rigid pins. Load proportioning is predicted for a number of geometries. Excellent correlation with experimental data is obtained. Experimental and computed surface strains are also found to compare well. The assumption of a radial cosine distribution of contact stress between pin and hole is shown to be substantially in error for some holes.

Griffin, O. H., Jr.; Hyer, M. W.; Yalamanchili, S. R.; Shuart, M. J.; Prasad, C. B.; Cohen, D.

1992-01-01

47

Load transfer in composite bolted joints  

NASA Technical Reports Server (NTRS)

The study deals with composite bolted joints, specifically those required to transmit primary loads. Consideration is given to the ultimate load capacity of quasi-isotropic bolted joint specimens as a function of the width of the joint, the diameter of the bolt, the joint thickness, and the number of bolts. Emphasis is placed on the effect of adding a second bolt, in tandem, on the load capacity of the joint.

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

1980-01-01

48

Ceramic matrix composite-metal brazed joints  

Microsoft Academic Search

A silicon nitride fibre-reinforced cordierite glass ceramic matrix composite has been brazed to titanium and stainless steel in argon with four different interlayer materials, copper, nickel, tungsten and a metal matrix composite (mmc). Joints were tested in shear and all but one failed in the ceramic composite. The highest strength joint, using a metal matrix interlayer to join cmc to

D. G. Dixon

1995-01-01

49

Delamination and Stitched Failure in Stitched Composite Joints  

NASA Technical Reports Server (NTRS)

The effect of stitches on the failure of a single lap joint configuration was determined in a combined experimental and finite element study. The experimental program was conducted to determine debond growth under static monotonic loading. The stitches were shown to delay the initiation of the debond and provide load transfer beyond the load necessary to completely debond the stitched lap joint. The experimentally determined debond length vs. applied load was used as an input parameter in the finite element analysis of both configurations. The strain energy release rates at the debond from were calculated using plate finite elements. Nonlinear fastener elements were used to model the stitches and multipoint constraints were used to model the contact problem. Models of the unstitched configuration showed significant values of modes I and II across the width of the joint and showed that mode III is zero at the centerline but increases near the free edge. Models of the stitched configuration showed that the stitches were effective in reducing mode I to zero, but had less of an effect on modes II and III.

Glaessgen, E. H.; Raju, I. S.; Poe, C. C., Jr.

1999-01-01

50

Interactive Composite Joint Design. Part 1.  

National Technical Information Service (NTIS)

A computing technique was developed to determine the feasibility of combining the several batch computer programs for the analysis of composite joints into one interactive computer program utilizing graphics display. This approach proved successful and pr...

C. G. Dietz L. J. Hart-Smith M. K. Smith

1978-01-01

51

Glue-Composite Joints in Technology.  

National Technical Information Service (NTIS)

The book deals with a new progressive method for joining of structural aluminum alloy elements production of composite, permanent, glued welded, glued riveted and glued threaded joints of high strength (especially under cyclic load), life, tightness and c...

V. N. Shavyrin N. K. Andreev A. A. Itskovich

1970-01-01

52

Planar scarf joints in composite repair  

NASA Technical Reports Server (NTRS)

This study examined the effects of varying certain important geometric parameters on the stresses in an adhesive repair of a thin composite laminate. The repair, a planar scarf joint with a doubler, was studied using finite element methods at scarf angles of 6 deg and 12 deg, damage lengths between 2.5 mm and 25 mm and doubler overlaps between 10 mm and 40 mm. Finite element models also showed that significant stress peaks occur at the ends of the scarf joint adhesive, similar to shear lag phenomena in lap joints. A bending model of the planar scarf joint with a doubler, based on mechanics of materials theory, was also developed.

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

1978-01-01

53

Adhesive joint and composites modeling in SIERRA.  

SciTech Connect

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.

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

2005-11-01

54

Nondestructive inspection in adhesive-bonded joint CFRP using pulsed phase thermography  

NASA Astrophysics Data System (ADS)

Many forms of damages in fiber reinforcement polymer (FRP) composites are difficult to detect because they occurs in subsurface layers of the composites. One challenging need for inspection capabilities is in adhesively bonded joints between composite components, a common location of premature failure in aerospace structures. This paper investigates pulsed phase thermography (PPT) imaging of fatigue damage in these adhesively bonded joints. Simulated defects were created to calibrate parameters for fatigue loading conditions, PPT imaging parameters, and a damage sizing algorithm for carbon fiber reinforced polymer (CFRP) single lap joints. Afterwards, lap joint specimens were fabricated with varying quality of manufacturing. PPT imaging of the pristine specimens revealed defects such as air bubbles, adhesive thickness variations, and weak bonding surface between the laminate and adhesive. Next, fatigue testing was performed and acquired PPT imaging data identified fatigue induced damage prior to final failure cycles. After failure of each sample, those images were confirmed by visual inspections of failure surface.

Shin, P. H.; Webb, S. C.; Peters, K. J.

2013-05-01

55

Critical joints in large composite aircraft structure  

NASA Technical Reports Server (NTRS)

A program was conducted at Douglas Aircraft Company to develop the technology for critical structural joints of composite wing structure that meets design requirements for a 1990 commercial transport aircraft. The prime objective of the program was to demonstrate the ability to reliably predict the strength of large bolted composite joints. Ancillary testing of 180 specimens generated data on strength and load-deflection characteristics which provided input to the joint analysis. Load-sharing between fasteners in multirow bolted joints was computed by the nonlinear analysis program A4EJ. This program was used to predict strengths of 20 additional large subcomponents representing strips from a wing root chordwise splice. In most cases, the predictions were accurate to within a few percent of the test results. In some cases, the observed mode of failure was different than anticipated. The highlight of the subcomponent testing was the consistent ability to achieve gross-section failure strains close to 0.005. That represents a considerable improvement over the state of the art.

Nelson, W. D.; Bunin, B. L.; Hart-Smith, L. J.

1983-01-01

56

Behavior of bolted joints in composite laminates  

SciTech Connect

This investigation characterizes bolted joint strength in Kevlar/epoxy and graphite/epoxy (0/45/90/-45)/sub 25/ composite laminates. The fundamental problem of a single bolt hole loaded symmetrically in tension is addressed. The first objective is to generalize the relationships between width, edge distance, hole size, thickness, washer diameter, and degree of lateral constraint with bolted joint strength based on experimental observations. The second objective is to numerically predict the same observation using only lamina properties. The effective laminate behavior is calculated with a nonlinear laminate analysis based on the material and the stacking sequence. The effective laminate properties are input into a nonlinear finite-element analysis to model the bolted joint. The degree of lateral surface constraint is also included in the analysis. The predicted bolted-joint failure regions and strengths were consistent with the experimental data, although improved nonlinear constitutive finite-element models are needed. The analysis is useful in predicting critical width, edge distance,and washer sizes needed to optimize bolted joint strength.

Jurf, R.A.

1986-01-01

57

An improved 2D model for bonded composite joints  

Microsoft Academic Search

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

Randolph A. Odi; Clifford M. Friend

2004-01-01

58

Mechanically fastened joints in woven fabric composites  

NASA Technical Reports Server (NTRS)

Strength analysis for composite bolted joints involves the mating of a stress analysis with an appropriate mode specific failure criterion for each of the primary failure modes. The stress analysis and failure criteria are independent of each other and can be manipulated separately in order to optimize the strength analysis package formed by their coupling. Material properties tests were conducted on rubber toughened graphite-epoxy material to measure the basic strength and stiffness in the warp and fill directions and in shear. Test matrices are summarized for investigations of laminate configuration, stacking sequence, fastener diameter, edge distance, fastener half spacing, laminate thickness, and fastener torque. A three dimensional finite element analysis computer program was written and failure criteria for net tension, shearout, and bearing were determined.

Wilson, D. W.; Bozarth, M. J.; Pipes, R. B.

1983-01-01

59

Adhesive Bonding Characterization of Composite Joints for Cryogenic Usage  

NASA Technical Reports Server (NTRS)

The development of polymer composite cryogenic tanks is a critical step in creating the next generation of launch vehicles. Future reusable launch vehicles need to minimize the gross liftoff weight (GLOW). This weight reduction is possible due to the large reduction in weight that composite materials can provide over current aluminum technology. In addition to composite technology, adhesively bonded joints potentially have several benefits over mechanically fastened joints, such as weight savings and cryogenic fluid containment. Adhesively bonded joints may be used in several areas of these cryogenic tanks, such as in lobe-to-lobe joints (in a multi-lobe concept), skirt-to-tank joint, strut-to-tank joint, and for attaching stringers and ring frames. The bonds, and the tanks themselves, must be able to withstand liquid cryogenic fuel temperatures that they contain. However, the use of adhesively bonded composite joints at liquid oxygen and hydrogen temperatures is largely unknown and must be characterized. Lockheed Martin Space Systems Company, Michoud Operations performed coupon-level tests to determine effects of material selection, cure process parameters, substrate surface preparation, and other factors on the strength of these composite joints at cryogenic temperatures. This led to the selection of a material and process that would be suitable for a cryogenic tank. KEY WORDS: Composites, Adhesive Bonding, Cryogenics

Graf, Neil A.; Schieleit, Gregory F.; Biggs, Robert

2000-01-01

60

The Efficient Design of Adhesive Bonded Joints  

Microsoft Academic Search

A concise method of analysis is used to study the numerous parameters influencing the stress distribution within the adhesive of a single lap joint. The formulation includes transverse shear and normal strain deformations. Both isotropic or anisotropic material systems of similar or dissimilar adherends are analysed. Results indicate that the primary Young's modulus of the adherend, the overlap length, and

W. James Renton; Jack R. Vinson

1975-01-01

61

Stress Analysis and Strength Prediction of Adhesively Bonded Composite Joints.  

National Technical Information Service (NTIS)

The state of the art in the stress analysis and strength prediction of adhesively bonded composite joints is presented. A generalized coordinate finite element analysis based on rectangular, cylindrical and wedge solid elements is developed and utilized f...

N. Rastogi A. E. Bogdanovich S. R. Soni

1998-01-01

62

Fabrication and mechanical properties of braided composite truss joint  

NASA Astrophysics Data System (ADS)

T-shape braided graphite/epoxy composite truss joints were fabricated by applying the conventional braiding technique and introducing three-dimensional taking up mechanism. This braided construction could be fabricated without cutting the fibers. As braided fabric could be inserted the longitudinal fiber (middle-end-fiber), this fabric was similar to triaxial woven fabrics. The T-shape composite truss joints that had braided construction with the middle-end-fibers were also fabricated. The mechanical properties of these T-shape composite truss joints were evaluated. It was clear that the middle-end-fibers were effective to improve the mechanical properties of T-shape braided composite truss joint.

Kobayashi, Hideteru; Nakama, Nobuhito; Maekawa, Zenichiro; Hamada, Hiroyuki; Fujita, Akihiro; Uozumi, Tadashi

63

Functionally Graded Adhesives for Composite Joints  

NASA Technical Reports Server (NTRS)

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.

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

2012-01-01

64

Thermomigration in SnPb composite flip chip solder joints  

NASA Astrophysics Data System (ADS)

We have used composite flip chip solder joints to study thermomigration. The composite solder joint has 97Pb3Sn on the Si side and eutectic 37Pb63Sn on the substrate side. Redistribution of Sn and Pb occurs in thermomigration, and we found that Sn has moved to the Si side (the hot end) and Pb to the substrate side (the cold end). We estimate the driving force that a temperature gradient of 1000 °C/cm or a temperature difference of 10 °C across a solder joint of 100 ?m in diameter is sufficient to induce the thermomigration.

Huang, Annie T.; Gusak, A. M.; Tu, K. N.; Lai, Yi-Shao

2006-04-01

65

Predicting the service-life of adhesively-bonded joints  

Microsoft Academic Search

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

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

2000-01-01

66

Critical composite joint subcomponents: Analysis and test results  

NASA Technical Reports Server (NTRS)

This program has been conducted to develop the technology for critical structural joints of a composite wing structure meeting design requirements for a 1990 commercial transport aircraft. A prime objective of the program was to demonstrate the ability to reliably predict the strength of large bolted composite joints. Load sharing between bolts in multirow joints was computed by a nonlinear analysis program (A4FJ) which was used both to assess the efficiency of different joint design concepts and to predict the strengths of large test articles representing a section from a wing root chord-wise splice. In most cases, the predictions were accurate to within a few percent of the test results. A highlight of these tests was the consistent ability to achieve gross-section failure strains on the order of 0.005 which represents a considerable improvement over the state of the art. The improvement was attained largely as the result of the better understanding of the load sharing in multirow joints provided by the analysis. The typical load intensity on the structural joints was about 40 to 45 thousand pound per inch in laminates having interspersed 37 1/2-percent 0-degree plies, 50-percent + or - 45-degrees plies and 12 1/2-percent 90-degrees plies. The composite material was Toray 300 fiber and Ciba-Geigy 914 resin, in the form of 0.010-inch thick unidirectional tape.

Bunin, B. L.

1983-01-01

67

21 CFR 888.3490 - Knee joint femorotibial metal/composite non-constrained cemented prosthesis.  

Code of Federal Regulations, 2010 CFR

...Knee joint femorotibial metal/composite non-constrained cemented...joint femorotibial metal/composite non-constrained cemented...polyethylene with carbon fibers composite and are intended for use with bone cement (§...

2009-04-01

68

21 CFR 888.3490 - Knee joint femorotibial metal/composite non-constrained cemented prosthesis.  

Code of Federal Regulations, 2010 CFR

...Knee joint femorotibial metal/composite non-constrained cemented...joint femorotibial metal/composite non-constrained cemented...polyethylene with carbon fibers composite and are intended for use with bone cement (§...

2010-04-01

69

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

Code of Federal Regulations, 2010 CFR

...888.3340 Hip joint metal/composite semi-constrained cemented...Identification. A hip joint metal/composite semi-constrained cemented...molecular weight polyethylene with carbon fibers composite. Both components are...

2010-04-01

70

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

Code of Federal Regulations, 2010 CFR

...3100 Ankle joint metal/composite semi-constrained cemented...Identification. An ankle joint metal/composite semi-constrained cemented...molecular weight polyethylene with carbon fibers composite, and is limited to those...

2009-04-01

71

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

Code of Federal Regulations, 2010 CFR

...3100 Ankle joint metal/composite semi-constrained cemented...Identification. An ankle joint metal/composite semi-constrained cemented...molecular weight polyethylene with carbon fibers composite, and is limited to those...

2010-04-01

72

21 CFR 888.3500 - Knee joint femorotibial metal/composite semi-constrained cemented prosthesis.  

Code of Federal Regulations, 2010 CFR

...Knee joint femorotibial metal/composite semi-constrained cemented...knee joint femorotibial metal/composite semi-constrained cemented...molecular weight polyethylene with carbon-fibers composite and is limited to those...

2010-04-01

73

21 CFR 888.3500 - Knee joint femorotibial metal/composite semi-constrained cemented prosthesis.  

Code of Federal Regulations, 2010 CFR

...Knee joint femorotibial metal/composite semi-constrained cemented...knee joint femorotibial metal/composite semi-constrained cemented...molecular weight polyethylene with carbon-fibers composite and is limited to those...

2009-04-01

74

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

Code of Federal Regulations, 2010 CFR

...888.3340 Hip joint metal/composite semi-constrained cemented...Identification. A hip joint metal/composite semi-constrained cemented...molecular weight polyethylene with carbon fibers composite. Both components are...

2009-04-01

75

Experimentation and Analysis of Composite Scarf Joint.  

National Technical Information Service (NTIS)

Composite bonded scarf repairs were examined by experimentally measuring and analytically predicting the residual curing strains and strains due to mechanical loading. To accomplish this a three prong approach was used: a full strain field through a repai...

B. M. Cook

2005-01-01

76

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

Microsoft Academic Search

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

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

2012-01-01

77

Hot melt joints for carbon fibre reinforced composites  

Microsoft Academic Search

The electric conductivity of carbon fibers and EVA thermoplastic adhesives in composite materials are exploited in a method for melting and\\/or hardening joint bonds. The joining method is based on the simultaneous use of electrical energy and mechanical pressure in joining sections of CFRP materials by means of hot melts. The EVA hot melt is used as a model adhesive

C. Netze; W. Michaeli

1990-01-01

78

Thermally Conductive Metal-Tube/Carbon-Composite Joints  

NASA Technical Reports Server (NTRS)

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.

Copeland, Robert J.

2004-01-01

79

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

NASA Technical Reports Server (NTRS)

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.

Moore, Thomas J.; Watson, Gordon K.

1994-01-01

80

Structural Health Monitoring of Adhesively Bonded Composite Joints  

NASA Astrophysics Data System (ADS)

In recent years, many aerospace organizations have researched and implemented composite materials to achieve better fuel efficiency as well as reduced maintenance cost. In addition to the use of composites, manufacturers are investigating the use of adhesive bonded joints and composite patch bonded repairs to extend the life of their in-service aircraft. Adhesive joints are superior to traditional mechanical fasteners as they reduce stress concentration zones and overall part count. However, the integrity of an adhesive joint is difficult to inspect. Inspection of adhesive joints may be carried out using interrogation technology such as Structural Health Monitoring (SHM). This thesis focuses on the evaluation of Acoustic-Ultrasonic (AU) SHM technique for the detection of crack and disbond growth. In addition to AU, Capacitance Disbond Detection Technique (CDDT) and the Surface Mountable Crack Detection System (SMCDS) were evaluated for the detection disbonds. Results of the AU system demonstrated that AU technology may be used to detect and quantify crack and disbond growth. It was also found that SMCDS and CDDT both complement each other, as SMCDS identified the location of disbond while CDDT quantify disbond.

Habib, Fady

81

Fatigue resistance of composite joints with countersunk composite and metal fasteners  

Microsoft Academic Search

Composite bolted joints were tested in cyclic loading to obtain results of the joint resistance to fatigue. Specimen plates manufactured from a carbon fibre\\/epoxy material system were joined by fasteners of three different types: composite, titanium torque-set, and titanium Huck-comp. Strain gauge measurements were carried out to analyse strain distribution and the load transfer between the bolt rows. An extensometer

Roman Starikov; Joakim Schön

2002-01-01

82

Adhesive Characterization and Progressive Damage Analysis of Bonded Composite Joints  

NASA Technical Reports Server (NTRS)

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 indicate that the model is capable of predicting the interactions of damage modes that lead to the failure of the joint.

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

2014-01-01

83

Experimental study on semi-rigid composite joints with steel beams and precast hollowcore slabs  

Microsoft Academic Search

The concept of semi-rigid composite connection has been widely researched in the past; however, most of the researches are limited to composite joints with metal deck flooring and solid concrete slabs. Composite construction incorporating precast concrete hollowcore slabs (HCU) is a recently developed composite floor system for buildings. The research on the structural behaviour of the semi-rigid composite joints with

F. Fu; D. Lam

2006-01-01

84

Resistance welding of thermoplastic composites skin\\/stringer joints  

Microsoft Academic Search

An experimental investigation of resistance welding of APC-2\\/AS4 PEEK\\/carbon fibre composite using a stainless steel mesh heating element is presented. A special specimen geometry, the skin\\/stringer configuration, was used to represent a typical reinforced aerospace structural joint. The specimens consisted of a flange, representing a stringer or frame, welded onto a skin laminate. The effects of the welding parameters such

M. Dubé; P. Hubert; A. Yousefpour; J. Denault

2007-01-01

85

Comportement mecanique des joints boulonnes en composites verre-polyester  

NASA Astrophysics Data System (ADS)

Glass fibre-reinforced polyester composite materials are being extensively used for general-purpose applications. For highly loaded structures, bolted joints are generally the preferred assembly method. However, bolted joints are usually the weakest link in a structure and they must therefore be designed with care. Specifically, the joint geometry, reinforcement type and lay-up should be chosen on a rational basis, otherwise the assembly may fail prematurely. The present study is concerned with the study of these material parameters. The mechanical response of bolted assemblies is studied for a range of six glass fibre-reinforced polyester laminates with reinforcements and lay-ups that are typical for general-purpose applications. In order to assess how changes in joint width or in joint end distance affect the behaviour of the joint, tests were carried out on three coupon geometries. In accordance with the standard test method ASTM D5961, a single-bolt double lap bolted joint configuration was used for the experimental characterisation. We investigated how the displacement measurement could best be made because currently there is a whole range of approaches in use and it is clear that the measured displacement quantity directly affects the stiffness values. A 3-D finite element model indicated that bolt deformation and fixture deformations affected the measured coupon displacement. The bearing stiffness was reduced by 26% on average when the width was reduced from six to two times the hole diameter. For the assemblies with a width of two times the hole diameter (w/D = 2) the bearing stiffness increased clearly with the tensile modulus of the tested materials. Both the experimental and numerical bearing stiffness values were much lower than those predicted by joint flexibility formulas. Hence, our results indicate that these joint flexibility formulas should be adapted if they are intended to be used for design of general-purpose glass fibre-reinforced polyester structures with bolt-hole clearance. The different material/geometry combinations led to very diverse failure modes and strengths, ranging from catastrophic low strength failures to progressive high strength failures. All the small coupons (w/D = 2; e/D = 3) failed catastrophically by tension. We observed that important characteristics of the bearing response such as damage stress, ultimate strength, failure mode and post-failure behaviour were related to reinforcement types and their stacking sequence. (Abstract shortened by UMI.)

Vangrimde, Bart

86

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

Microsoft Academic Search

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

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

87

Probabilistic Evaluation of Bolted Joints in Polymer Matrix Composites  

NASA Technical Reports Server (NTRS)

Computational methods are described to probabilistically simulate fracture in bolted composite structures. Progressive fracture is simulated via an innovative approach independent of stress intensity factors and fracture toughness. The effect on structure damage of design variable uncertainties is quantified. The Fast Probability Integrator is used to assess the scatter in the composite structure response before and after damage. Sensitivity of the response to design variables is evaluated. The methods are demonstrated for bolted joint polymer matrix composite panels under end loads. The effects of fabrication process are included in the simulation of damage in the bolted panel. The results show that the most effective way to reduce the end displacement at fracture is to control the load and ply thickness.

Chamis, C. C.; Minnetyan, L.

1997-01-01

88

Cyclic stress durability testing of lap shear joints exposed to hot-wet conditions  

Microsoft Academic Search

Adhesively bonded single lap shear joints are often required to transfer fluctuating loads in service, yet the majority of accelerated durability tests are carried out using either no load, or a sustained load. A number of researchers have emphasised the need for the development of faster and more realistic techniques for comparing the durability of different adhesive-pretreatment combinations. The aim

Paul Briskham; Gordon Smith

2000-01-01

89

Static Strength Characteristics of Mechanically Fastened Composite Joints  

NASA Technical Reports Server (NTRS)

The analysis of mechanically fastened composite joints presents a great challenge to structural analysts because of the large number of parameters that influence strength. These parameters include edge distance, width, bolt diameter, laminate thickness, ply orientation, and bolt torque. The research presented in this report investigates the influence of some of these parameters through testing and analysis. A methodology is presented for estimating the strength of the bolt-hole based on classical lamination theory using the Tsai-Hill failure criteria and typical bolthole bearing analytical methods.

Fox, D. E.; Swaim, K. W.

1999-01-01

90

Enhancement of Composite Scarf Joint Interface Strength Through Carbon Nanotube Reinforcement.  

National Technical Information Service (NTIS)

The objective of this research is to investigate the potentially significant improvement to scarf joint bonding achieved through the dispersion of carbon nanotubes along the interface of the composite joint. The study examines various factors that may aff...

R. E. Slaff

2007-01-01

91

SCARF Joint Technique with Cocured and Precured Patches for Composite Repair.  

National Technical Information Service (NTIS)

The scarf joint technique is one of the latest techniques used for repairing composite aircraft structures. This paper describes scarf joints comprised of vacuum and autoclave precured and cocured fiber glass epoxy patches bonded to autoclave and vacuum p...

F. Elaldi S. Lee R. F. Scott

1995-01-01

92

[Experimental studies on polyacetal composites for joint prosthesis].  

PubMed

Composite polymer resin is one of the most promising materials for its excellent bio-functions. The purpose of the present studies is to prove the applicability of polyacetal composites as a biomaterial for joint prostheses from in vivo as well as in vitro experiments. Materials and methods: The polymeric materials tested in the studies were acetal copolymer resin (POM) reinforced with 20% carbon fiber (CR20), POM with 10% fluorine powder (YF 10), POM alone, ultra high molecular weight polyethylene (UHMWPE) and UHMWPE reinforced with 10% carbon fiber (Poly two). Experiment I: Evaluation of biocompatibility in vivo by injecting polymeric powders into the abdominal cavity of mice, and in vitro with a tissue culture method. Experiment II: Friction and wear tests with a slider and a plate under different lubricants, the slider was made of stainless steel or ceramic. Coefficient of friction and specific wear rate were measured, and the wear surface was observed with scanning electron microscope (SEM). Müller type acetabular cups used for the simulation test were made of reinforced POMs, UHMWPE, and Poly two. A walk simulator was made to test the tribological behavior of hip joint prostheses in which the frictional counterpart was made of ceramic. Roughness of the wear surface, and ultimate frictional torque were measured and the surface microstructure was observed with SEM. Experiment III: Application for joint replacement. As a first step, screwshaped test pieces were inserted into the proximal end of the tibia of Beagle dogs, and ultimate rotating torque was measured to investigate the degree of fixation of reinforced POMs to the bone. A hip joint prosthesis of self-locking and cementless type was made and implanted in 12 dogs. Nine dogs were sacrificed more than 24 weeks after the implantation and investigated radiographically and histopathologically. Results and conclusions: Reinforced POMs showed similar biocompatibility as other biomaterials for joint prostheses. In the combination with ceramic, the coefficient of CR20 tends to decrease with the increase of load and prolapsed time. SEM findings showed low specific wear. After the simulation test, the surface of CR20 cup became smoother. Poly two showed almost the same frictional torque as CR20, but its reinforced carbon fibers seem to be easily drifted away from the wear surface. The CR20 test pieces showed as firm fixation to the bone as those of stainless steel. The implantation tests were excellent in 2 and good in 3 dogs at the point of fixation of the socket with the bone out of 9 dogs tested.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:6520501

Maeda, M

1984-09-01

93

Enhancement of composite scarf joint interface strength through carbon nanotube reinforcement  

Microsoft Academic Search

It was investigated whether there was a potentially significant improvement to scarf joint bonding that was achieved through\\u000a the dispersion of carbon nanotubes (CNTs) along the interface of the composite joint. The study examined various factors that\\u000a might affect CNT-reinforced joint interface strength. Each composite joint consisted of a vinyl-ester matrix base (DERAKANE\\u000a 510-A) interlaced with a carbon fiber weave

Y. W. Kwon; R. Slaff; S. Bartlett; T. Greene

2008-01-01

94

Lamb wave propagation in Z-pin reinforced co-cured composite pi-joints  

Microsoft Academic Search

This paper presents an initial study on Lamb wave propagation characteristics in z-pin reinforced, co-cured composite pi-joints for the purposes of structural health monitoring (SHM). Pi-joint test articles were designed and created to replicate a co-cured, all composite skin-spar joint found within a typical aircraft wing structure. Because pi-joints exhibit various complex damage modes, formal studies are required if SHM

Eric D. Swenson; Som R. Soni; Hitesh Kapoor

2010-01-01

95

Joint Composite-Rotation Adiabatic-Sweep Isotope Filtration  

PubMed Central

Joint composite-rotation adiabatic-sweep isotope filter are derived by combining the composite-rotation [A. C. Stuart, K. A. Borzilleri, J. M. Withka, and A. G. Palmer, J. Am. Chem. Soc. 121, 5346–5347 (1999)] and adiabatic-sweep [C. Zwahlen, P. Legault, S. J. F. Vincent, J. Greenblatt, R. Konrat, and L. E. Kay, J. Am. Chem. Soc. 119, 6711–6721 (1997); ?. Kup?e and R. Freeman, J. Magn. Reson. 127, 36–48 (1997)] approaches. The joint isotope filters have improved broadband filtration performance, even for extreme values of the one-bond 1H-13C scalar coupling constants in proteins and RNA molecules. An average Hamiltonian analysis is used to describe evolution of the heteronuclear scalar coupling interaction during the adiabatic sweeps within the isotope filter sequences. The new isotope filter elements permit improved selective detection of NMR resonance signals originating from 1H spins attached to an unlabeled natural abundance component of a complex in which other components are labeled with 13C and 15N isotopes.

Valentine, Elizabeth R.; Ferrage, Fabien; Massi, Francesca; Cowburn, David; Palmer, Arthur G.

2007-01-01

96

Mixed mode failure criteria for a glass\\/epoxy composite and an adhesively bonded composite\\/composite joint  

Microsoft Academic Search

Mixed mode initiation failure criteria for the delamination of a glass\\/epoxy composite and its composite\\/composite bonded joint are compared. Tests were conducted under mode I (DCB), mode II (ENF) and mixed mode I\\/II (MMB) loading. Mode partitioning was performed using beam theory. The initiation failure point was defined both by the non-linearity point on the load\\/displacement curve and by the

F. Ducept; P. Davies; D. Gamby

2000-01-01

97

The strain energy release rates in adhesively bonded balanced and unbalanced specimens and lap joints  

Microsoft Academic Search

An analytical model is developed to determine the strain energy release rate in adhesive joints of various configurations such as the double-cantilever beam and single-lap joints. The model is based on asymptotic analysis of adhesive layer stresses and Irwin’s crack closure integral. Closed-form solutions are presented for balanced and unbalanced joints under mode I, II and mixed-mode I\\/II that take

Khaled Shahin; Farid Taheri

2008-01-01

98

Isothermal low cycle fatigue behavior of Sn8Zn3Bi on single shear solder joint  

Microsoft Academic Search

Tin-zinc solder with the low melting temperature below 200 °C is an attractive alternative to eutectic tin-lead. The addition of bismuth improves wettability of Sn-Zn alloy. Low cycle isothermal mechanical fatigue testing of solder joints of Sn-8Zn-3Bi (wt%) and Sn-37Pb were tested in a solder joint of single lap shear sample with a multi-functional Instron 4458-Microtester. Solder joints around 0.5mm

Peng Sun; Cristina Andersson; Liqiang Cao; Zhonghe Lai; Zhaonian Cheng; Xicheng Wei; Johan Liu

2005-01-01

99

Performance of Adhesive Joints 1996-1999. Project PAJ2. Dynamic Performanace of Adhesively Bonded Joints. Report No. 3. Proposed Draft for the Revision of ISO 11003-2. The Thick-Adherend Shear Test Method.  

National Technical Information Service (NTIS)

This part of ISO 11003 specifies a test method for determining the shear behavior of an adhesive in a single lap joint bonded assembly when subjected to a tensile force. The test is performed on a specimens consisting of thick, rigid adherends, with a sho...

G. D. Dean

1997-01-01

100

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

Microsoft Academic Search

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

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

2011-01-01

101

Effect of Adhesive Ductility on Cyclic Debond Mechanism in Composite-to-Composite Bonded Joints  

Microsoft Academic Search

An investigation of an adhesively bonded composite joint with a brittle adhesive was conducted to characterize both the static and fatigue debond growth mechanism under mode I and mixed mode I-II loadings. The bonded system consisted of graphite\\/epoxy adherends bonded with FM-400 adhesive. Two specimen types were tested: (1) a double-cantilever-beam specimen for mode I loading and (2) a cracked-lap-shear

S. Mall; K. T. Yun

1987-01-01

102

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

Microsoft Academic Search

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

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

2008-01-01

103

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

Microsoft Academic Search

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

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

2009-01-01

104

Effect of service environments on adhesively bonded joints in composite structures  

Microsoft Academic Search

The models employed in the present computational methods for evaluating severe service-environment effects on adhesively bonded joints in composites are based on composite analyses and structural mechanics, encompassing nonlinear environmental degradation. The methods are demonstrated for the case of a butt joint with a single doubler, subjected to the environmental effects as well as static and cyclic loads. The highest

S. N. Singhal; C. C. Chamis; P. L. N. Murthy

1992-01-01

105

Analytical Model for Shear Strengthening of RC Beam-Column Joints Using Composite Materials  

Microsoft Academic Search

An analytical model, based on principal tensile stresses vs. joint shear deformation rules, for the evaluation of reinforced concrete (RC) joints strengthened with fibre reinforced polymer (FRP) composite materials is presented. For this purpose, existing model available in literature is simplified and step-by-step iterative procedure is given which separately evaluates the shear contributions provided by the composite material and by

S. Pampanin

106

Adhesion of Geopolymer Bonded Joints Considering Surface Treatments  

Microsoft Academic Search

In this study the adhesion properties of a geopolymer-based adhesive on metallic substrates are investigated, considering different surface conditions. Mechanical treatments (grit-blasting and sand-blasting) and chemical treatments (nitro-phosphoric acid and silanization) were performed on steel and aluminium plates. Single lap joint specimens were tested in order to access the influence of these pretreatments on the shear bond strength. The surfaces

S. De Barros; J. R. De Souza; K. C. Gomes; E. M. Sampaio; N. P. Barbosa; S. M. Torres

2012-01-01

107

Experimental Investigation of Composite Pressure Vessel Performance and Joint Stiffness for Pyramid and Inverted Pyramid Joints  

NASA Technical Reports Server (NTRS)

The focus of this study is on the suitability in the application of classical laminate theory analysis tools for filament wound pressure vessels with adhesive laminated joints in particular: pressure vessel wall performance, joint stiffness and failure prediction. Two 18-inch diameter 12-ply filament wound pressure vessels were fabricated. One vessel was fabricated with a 24-ply pyramid laminated adhesive double strap butt joint. The second vessel was fabricated with the same number of plies in an inverted pyramid joint. Results from hydrostatic tests are presented. Experimental results were used as input to the computer programs GENLAM and Laminate, and the output compared to test. By using the axial stress resultant, the classical laminate theory results show a correlation within 1% to the experimental results in predicting the pressure vessel wall pressure performance. The prediction of joint stiffness for the two adhesive joints in the axial direction is within 1% of the experimental results. The calculated hoop direction joint stress resultant is 25% less than the measured resultant for both joint configurations. A correction factor is derived and used in the joint analysis. The correction factor is derived from the hoop stress resultant from the tank wall performance investigation. The vessel with the pyramid joint is determined to have failed in the joint area at a hydrostatic pressure 33% value below predicted failure. The vessel with the inverted pyramid joint failed in the wall acreage at a hydrostatic pressure within 10% of the actual failure pressure.

Verhage, Joseph M.; Bower, Mark V.; Gilbert, Paul A. (Technical Monitor)

2001-01-01

108

Vibration Analysis for Damage Detection in Metal-to-Metal Adhesive Joints  

Microsoft Academic Search

Vibration based non-destructive evaluation shows promise for damage detection in metal-to-metal adhesive joints. This research\\u000a investigates an experimental technique to diagnose damage in single-lap adhesive joints subject to cyclical tensile loading.\\u000a Vibration analysis reveals that damage can be correlated with changes in identified modal damping ratios. Constant amplitude\\u000a forcing functions are employed to eliminate amplitude-dependent nonlinearities in the dynamic response

P. Pandurangan; G. D. Buckner

2006-01-01

109

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

NASA Technical Reports Server (NTRS)

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.

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

2007-01-01

110

Strengths of composite-to-metal double-lap bolted joints  

Microsoft Academic Search

A three-dimensional analysis was proposed to study the through-the-thickness clamping effect on the bearing failure of double-lap bolted laminated composite joints. Experiments were first performed to characterize the material response due to bearing failure in composite bolted joints with and without lateral clamp-up supports. Composite plates made of T800H\\/3900-2 graphite\\/epoxy were selected in the tests, and various washer sizes and

Hsien-Tang Sun

1998-01-01

111

Analysis of Bonded Joints Between the Facesheet and Flange of Corrugated Composite Panels  

NASA Technical Reports Server (NTRS)

This paper outlines a method for the stress analysis of bonded composite corrugated panel facesheet to flange joints. The method relies on the existing HyperSizer Joints software, which analyzes the bonded joint, along with a beam analogy model that provides the necessary boundary loading conditions to the joint analysis. The method is capable of predicting the full multiaxial stress and strain fields within the flange to facesheet joint and thus can determine ply-level margins and evaluate delamination. Results comparing the method to NASTRAN finite element model stress fields are provided illustrating the accuracy of the method.

Yarrington, Phillip W.; Collier, Craig S.; Bednarcyk, Brett A.

2008-01-01

112

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

NASA Technical Reports Server (NTRS)

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.

Higgins, John E.; Pelham, Larry

2008-01-01

113

Tensile behavior of bonded scarf joints between composite adherends  

NASA Technical Reports Server (NTRS)

Tensile tests of bonded scarf joints indicate that shallow angle joints are sensitive to slight adherend tip bluntness. For scarf angles ranging from 9.2 to 1.1 degrees stress concentrations from blunt adherend tips significantly limit the increased strength expected from larger bond area. The bonded joints fail by two failure modes depending on the scarf angle. Although most of the joints in this study were scarfed by a surface grinder, small angle scarfs can be cut very accurately with a hand held rotary bur.

Adkins, David W.; Pipes, R. Byron

1989-01-01

114

Scarf Joint Modeling and Analysis of Composite Materials.  

National Technical Information Service (NTIS)

The objective of this study is to investigate joint strength of the scarf joint configuration, constructed from carbon and glass woven fabric hybrid laminates, with different material combinations. Glass/glass, glass/carbon, carbon/glass, and carbon/carbo...

A. Marron

2009-01-01

115

Scarf Joints of Composite Materials: Testing and Analysis  

NASA Astrophysics Data System (ADS)

The objective of this study is to develop a reliable computational model in order to investigate joint strengths of scarf joint configurations constructed from carbon-fiber and glass-fiber woven fabric laminates with different material combinations like glass/glass, glass/carbon, carbon/glass, and carbon/carbon under various loading conditions such as axial, bending moment and shear loading. Both experimental and computational studies are conducted. For the experimental study, specimens made of hybrid scarf joints using carbon-fiber and glass-fiber woven fabrics are tested under compressive loadings to determine their joint failure strengths. Computational models are then developed using the discrete resin layer model along with fracture mechanics and virtual crack closure techniques. The numerical models are validated against the experimental data. The validate models are used to predict the joint strengths under different loading conditions such as axial, shear, and bending moment loadings.

Kwon, Y. W.; Marrón, A.

2009-12-01

116

Thermal Effects on the Bearing Behavior of Composite Joints  

NASA Technical Reports Server (NTRS)

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.

Walker, Sandra Polesky

2001-01-01

117

Active Metal Brazing and Characterization of Brazed Joints in Titanium to Carbon-Carbon Composites  

NASA Technical Reports Server (NTRS)

The Ti-metal/C-C composite joints were formed by reactive brazing with three commercial brazes, namely, Cu-ABA, TiCuNi, and TiCuSiI. The joint microstructures were examined using optical microscopy and scanning electron microscopy (SEM) coupled with energy dispersive spectrometry (EDS). The results of the microstructure analysis indicate solute redistribution across the joint and possible metallurgical bond formation via interdiffusion, which led to good wetting and spreading. A tube-on-plate tensile test was used to evaluate joint strength of Ti-tube/ C-C composite joints. The load-carrying ability was greatest for the Cu-ABA braze joint structures. This system appeared to have the best braze spreading which resulted in a larger braze/C-C composite bonded area compared to the other two braze materials. Also, joint loadcarrying ability was found to be higher for joint structures where the fiber tows in the outer ply of the C-C composite were aligned perpendicular to the tube axis when compared to the case where fiber tows were aligned parallel to the tube axis.

Singh, M.; Shpargel, T. P.; Morscher, G. N.; Asthana, R.

2006-01-01

118

Seismic performance of steel reinforced ultra high-strength concrete composite frame joints  

NASA Astrophysics Data System (ADS)

To investigate the seismic performance of a composite frame comprised of steel reinforced ultra high-strength concrete (SRUHSC) columns and steel reinforced concrete (SRC) beams, six interior frame joint specimens were designed and tested under low cyclically lateral load. The effects of the axial load ratio and volumetric stirrup ratio were studied on the characteristics of the frame joint performance including crack pattern, failure mode, ductility, energy dissipation capacity, strength degradation and rigidity degradation. It was found that all joint specimens behaved in a ductile manner with flexural-shear failure in the joint core region while plastic hinges appeared at the beam ends. The ductility and energy absorption capacity of joints increased as the axial load ratio decreased and the volumetric stirrup ratio increased. The displacement ductility coefficient and equivalent damping coefficient of the joints fell between the corresponding coefficients of the steel reinforced concrete (SRC) frame joint and RC frame joint. The axial load ratio and volumetric stirrup ratio have less influence on the strength degradation and more influence on the stiffness degradation. The stiffness of the joint degrades more significantly for a low volumetric stirrup ratio and high axial load ratio. The characteristics obtained from the SRUHSC composite frame joint specimens with better seismic performance may be a useful reference in future engineering applications.

Yan, Changwang; Jia, Jinqing

2010-09-01

119

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

SciTech Connect

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.

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

120

An Investigation of the Tensile Strength of a Composite-To-Metal Adhesive Joint  

Microsoft Academic Search

The present study examines the feasibility of a simple concept composite-to-metal butt joint through the performance of both\\u000a numerical and experimental studies. The composite part is made of glass\\/epoxy unidirectional layers made with the vacuum bag\\u000a method. The geometry of the joint is typical for marine applications and corresponds to a low stiffness ratio. Two major parameters\\u000a are investigated, namely

Nicholas G. Tsouvalis; Vassilios A. Karatzas

2011-01-01

121

Sensitivity of embedded fibre optic Bragg grating sensors to disbonds in bonded composite ship joints  

Microsoft Academic Search

The potential application of embedded fibre optic Bragg grating strain sensors for the health monitoring of adhesively bonded composite ship joints is investigated in this paper. Bragg grating sensors were embedded at various locations along the interface of adhesively bonded glass-reinforced plastic composite joints with artificially introduced disbonds to assess their capability to detect bond-line damage under in-plane shear and

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

2004-01-01

122

The joint capsule: structure, composition, ageing and disease.  

PubMed

The joint capsule is vital to the function of synovial joints. It seals the joint space, provides passive stability by limiting movements, provides active stability via its proprioceptive nerve endings and may form articular surfaces for the joint. It is a dense fibrous connective tissue that is attached to the bones via specialised attachment zones and forms a sleeve around the joint. It varies in thickness according to the stresses to which it is subject, is locally thickened to form capsular ligaments, and may also incorporate tendons. The capsule is often injured, leading to laxity, constriction and/or adhesion to surrounding structures. It is also important in rheumatic disease, including rheumatoid arthritis and osteoarthritis, crystal deposition disorders, bony spur formation and ankylosing spondylitis. This article concentrates on the specialised structures of the capsule--where capsular tissues attach to bone or form part of the articulation of the joint. It focuses on 2 joints: the rat knee and the proximal interphalangeal (PIP) joint of the human finger. The attachments to bone contain fibrocartilage, derived from the cartilage of the embryonic bone rudiment and rich in type II collagen and glycosaminoglycans. The attachment changes with age, when type II collagen spreads into the capsular ligament or tendon, or pathology--type II collagen is lost from PIP capsular attachments in rheumatoid arthritis. Parts of the capsule that are compressed during movement adapt by becoming fibrocartilaginous. Such regions accumulate cartilage-like glycosaminoglycans and may contain type II collagen, especially in aged material.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7928639

Ralphs, J R; Benjamin, M

1994-06-01

123

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

NASA Technical Reports Server (NTRS)

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.

Zhao, Yi

2003-01-01

124

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

NASA Technical Reports Server (NTRS)

The development of several types of graphite/polyimide (GR/PI) bonded and bolted joints is reported. The program consists of two concurrent tasks: (1) design and test of specific built up attachments; and (2) evaluation of standard advanced bonded joint concepts. A data base for the design and analysis of advanced composite joints for use at elevated temperatures (561K (550 deg F)) to design concepts for specific joining applications, and the fundamental parameters controlling the static strength characteristics of such joints are evaluated. Data for design and build GR/PI of lightly loaded flight components for advanced space transportation systems and high speed aircraft are presented. Results for compression and interlaminar shear strengths of Celion 6000/PMR-15 laminates are given. Static discriminator test results for type 3 and type 4 bonded and bolted joints and final joint designs for TASK 1.4 scale up fabrication and testing are presented.

1981-01-01

125

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

NASA Technical Reports Server (NTRS)

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 1200 C 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.

Singh, M.

1999-01-01

126

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

NASA Technical Reports Server (NTRS)

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.

Singh, M.

1999-01-01

127

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

NASA Technical Reports Server (NTRS)

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.

Bunin, Bruce L.

1985-01-01

128

Experimental Study of the Compression Response of Fluted-Core Composite Panels with Joints  

NASA Technical Reports Server (NTRS)

Fluted-core sandwich composites consist of integral angled web members spaced between laminate face sheets, and may have the potential to provide benefits over traditional sandwich composites for certain aerospace applications. However, fabrication of large autoclave-cured fluted-core cylindrical shells with existing autoclaves will require that the shells be fabricated in segments, and joined longitudinally to form a complete barrel. Two different longitudinal fluted-core joint designs were considered experimentally in this study. In particular, jointed fluted-core-composite panels were tested in longitudinal compression because longitudinal compression is the primary loading condition in dry launch-vehicle barrel sections. One of the joint designs performed well in comparison with unjointed test articles, and the other joint design failed at loads approximately 14% lower than unjointed test articles. The compression-after-impact (CAI) performance of jointed fluted-core composites was also investigated by testing test articles that had been subjected to 6 ft-lb impacts. It was found that such impacts reduced the load-carrying capability by 9% to 40%. This reduction is dependent on the joint concept, component flute size, and facesheet thickness.

Schultz, Marc R.; Rose, Cheryl A.; Guzman, J. Carlos; McCarville, Douglas; Hilburger, Mark W.

2012-01-01

129

Crack detection in adhesive joints: use of strain gages in aggressive environments  

Microsoft Academic Search

A large three-dimensional finite element model was used to predict the response of miniature resistance strain gages to the initiation and growth of center and corner cracks in the fillet of an asymmetric single lap-shear joint. Experiments were conducted to assess the feasibility of the technique under conditions of accelerated durability testing. Drift in the strain-gage output complicated the interpretation

M. Papini; J. K. Spelt

1992-01-01

130

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

NASA Technical Reports Server (NTRS)

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.

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

1981-01-01

131

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

SciTech Connect

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.

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

132

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

Microsoft Academic Search

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

L. J. Westfall; D. W. Petrasek

1985-01-01

133

Interdisciplinary approach to predictive modeling of structural adhesive bonding, chromic acid anodized Ti-6Al-4V: its characterization and its single lap bond strength to heat-resistant adhesives. Summary report, January 1982-June 1987  

SciTech Connect

Anodized titanium-aluminum-vanadium adhesive bonds exhibit improved corrosion resistance and a higher strength-to-weight ratio compared to conventional metal-bonding techniques for primary and/or secondary structural applications. This work was conducted to identify chromic acid (CA) anodization and bond process conditions that produced durable, structural applications. This work was conducted to identify chromic acid (CA) anodization and bond process conditions which produced durable, structural anodized titanium-aluminum-vanadium single lap bonds and to understand why these conditions were necessary. Heat-resistant adhesives tested had reported service temperatures greater than 423K, and were: polysulfone; polyethersulfone;polyphenylquinoxaline; polyetherimide, both unfilled and 20% glass filled; and 50% calcium-carbonate-filled polyimide. Hydrofluoric acid (HF) added to the CA anodization solution was necessary to produce structural bonds. Chromic acid hydrogen fluoride oxide was more porous, and thicker than the CA anodic oxide perhaps promoting physical and oxide/adhesive interphase mechanical interlock.

Skiles, J.A.; Wightman, J.P.

1987-06-01

134

Thermal-Stress Reducer For Metal/Composite Joint  

NASA Technical Reports Server (NTRS)

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.

Glinski, Robert L.

1993-01-01

135

Characterization of Brazed Joints of C-C Composite to Cu-clad-Molybdenum  

NASA Technical Reports Server (NTRS)

Carbon-carbon composites with either pitch+CVI matrix or resin-derived matrix were joined to copper-clad molybdenum using two active 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 de-lamination in resin-derived C-C composite due to its low inter-laminar shear strength. Extensive braze penetration of the inter-fiber channels in the pitch+CVI C-C composites was observed. The relatively low brazing temperatures (<950 C) precluded melting of the clad layer and restricted the redistribution of alloying elements but led to metallurgically sound composite joints. The Knoop microhardness (HK) distribution across the joint interfaces revealed sharp gradients at the Cu-clad-Mo/braze interface and higher hardness in Ticusil (approx.85-250 HK) than in Cusil-ABA (approx.50-150 HK). These C-C/Cu-clad-Mo joints with relatively low thermal resistance may be promising for thermal management applications.

Singh, M.; Asthana, R.

2008-01-01

136

Design, Fabrication, and Testing of Ceramic Joints for High Temperature SiC/SiC Composites  

NASA Technical Reports Server (NTRS)

Various issues associated with the design and mechanical evaluation of joints of ceramic matrix composites are discussed. The specific case of an affordable, robust ceramic joining technology (ARCJoinT) to join silicon carbide (CG-Nicalon(sup TM)) fiber-reinforced-chemically vapor infiltrated (CVI) silicon carbide matrix composites is addressed. Experimental results are presented for the time and temperature dependence of the shear strength of these joints in air up to 1200 C. From compression testing of double-notched joint specimens with a notch separation of 4 mm, it was found that the apparent shear strength of the joints decreased from 92 MPa at room temperature to 71 MPa at 1200 C. From shear stress-rupture testing in air at 1200 C it was found that the shear strength of the joints decreased rapidly with time from an initial shear strength of 71 to 17.5 MPa after 14.3 hr. The implications of these results in relation to the expected long-term service life of these joints in applications at elevated temperatures are discussed.

Singh, Mrityunjay; Lara-Curzio, Edgar

2000-01-01

137

SIMULATION OF PROGRESSIVE DAMAGE IN BOLTED COMPOSITE JOINTS  

Microsoft Academic Search

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 \\

Hannes Koerber; Pedro P. Camanho

138

Health monitoring of composite repairs and joints using optical fibres  

Microsoft Academic Search

With the increasing use of composite bonded repairs to ageing aircraft there is a growing need to monitor their in-service health. One approach is to incorporate various in situ health monitoring systems within the repair. This paper summarises a collaborative research program between the Australian Defence Science and Technology Organisation (DSTO) and the DSTO Centre of Expertise in Structural Mechanics

R Jones; S Galea

2002-01-01

139

Mechanical Characterization of Reactively Brazed Metal-Composite Joints for Heat Rejection Systems  

NASA Technical Reports Server (NTRS)

The joining of metal tubes to composite plates is required for heat-rejection components in several space applications. Currently a number of different braze compositions are being evaluated as to their effectiveness. Such tube-plate configurations cannot be represented by traditional methods of testing, e.g., lap joints. The joined region is not between two flat surfaces, but rather between a flat surface and a curved surface. Therefore, several tests have been employed to ascertain the effectiveness of the different braze approaches in tension and in shear that are both simple and representative of the actual system and relatively straightforward in analysis. The results of these "tube tests" will be discussed for the three different braze compositions, Cu-ABA, Ti-Cu-Sil, and Ti-Cu-Ni. In addition, fracture analysis of the failed joints was performed and offers insights into the cause of joint failure and the distinctions which need to be made between the "strength" of a joint versus the "load carrying ability" of a joint.

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

2005-01-01

140

Studies on the Performance of RC Beam-Column Joints Strengthened Using Different Composite Materials  

NASA Astrophysics Data System (ADS)

Many reinforced concrete structures in our country are in a deteriorated or distressed state. Hence strengthening such structures or reducing the load limit on them is becoming necessary to extend their service life. Beam-column joint is the crucial zone in a reinforced concrete moment resisting frame since it is subjected to large forces during severe ground shaking. In the present study, an attempt has been made to determine the cost-effective composite material and optimum number of layers of composite material for strengthening beam-column joints. Specimens were strengthened using ferrocement, glass fibre reinforced polymer (GFRP) and carbon fibre reinforced polymer (CFRP) and studied their behaviour under static as well as cyclic loading. It was found that the rotation at ultimate moment of all the strengthened beam-column joints were greater than that of the control specimens. The specimens strengthened with more number of layers of strengthening material showed better moment-rotation characteristics. The joints strengthened using GFRP showed better performance in terms of ultimate load, moment rotation characteristics, ductility, energy absorption capacity and strength-to-cost ratio, when compared to that of the specimens strengthened with other composite materials. However, CFRP strengthened specimens showed good ductility and better cracking characteristics and prevented the failure at the joint.

Sheela, S.; Anu Geetha, B.

2012-02-01

141

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

SciTech Connect

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.

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

2010-01-01

142

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

NASA Technical Reports Server (NTRS)

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 760F (1400F). The TMF facility designed for testing tungsten fiber reinforced metal matrix composites permits test specimen temperature excursions from room temperature to 1430C (2600F) with controlled heating and loading rates. A strain-measuring device measures the strain in the test section of the specimen during each heating and cooling cycle with superimposed loads. Data is collected and recorded by a computer. The second facility is designed to test composite/metal attachment bond joints and to permit heating to a maximum temperature of 760C (1400F) within 10 min and cooling to 150C (300F) within 3 min. A computer controls specimen temperature and load cycling.

Westfall, Leonard J.; Petrasek, Donald W.

1988-01-01

143

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

NASA Technical Reports Server (NTRS)

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 temperature to 1430C (2600F) with controlled heating and loading rates. A strain-measuring device measures the strain in the test section of the specimen during each heating and cooling cycle with superimposed loads. Data is collected and recorded by a computer. The second facility is designed to test composite/metal attachment bond joints and to permit heating to a maximum temperature of 760C (1400F) within 10 min and cooling to 150C (300F) within 3 min. A computer controls specimen temperature and load cycling.

Westfall, L. J.; Petrasek, D. W.

1985-01-01

144

Fabrication and Testing of Durable Redundant and Fluted-Core Joints for Composite Sandwich Structures  

NASA Technical Reports Server (NTRS)

The development of durable bonded joint technology for assembling composite structures is an essential component of future space technologies. While NASA is working toward providing an entirely new capability for human space exploration beyond low Earth orbit, the objective of this project is to design, fabricate, analyze, and test a NASA patented durable redundant joint (DRJ) and a NASA/Boeing co-designed fluted-core joint (FCJ). The potential applications include a wide range of sandwich structures for NASA's future launch vehicles. Three types of joints were studied -- splice joint (SJ, as baseline), DRJ, and FCJ. Tests included tension, after-impact tension, and compression. Teflon strips were used at the joint area to increase failure strength by shifting stress concentration to a less sensitive area. Test results were compared to those of pristine coupons fabricated utilizing the same methods. Tensile test results indicated that the DRJ design was stiffer, stronger, and more impact resistant than other designs. The drawbacks of the DRJ design were extra mass and complex fabrication processes. The FCJ was lighter than the DRJ but less impact resistant. With barely visible but detectable impact damages, all three joints showed no sign of tensile strength reduction. No compression test was conducted on any impact-damaged sample due to limited scope and resource. Failure modes and damage propagation were also studied to support progressive damage modeling of the SJ and the DRJ.

Lin, Shih-Yung; Splinter, Scott C.; Tarkenton, Chris; Paddock, David A.; Smeltzer, Stanley S.; Ghose, Sayata; Guzman, Juan C.; Stukus, Donald J.; McCarville, Douglas A.

2013-01-01

145

Adhesively bonded lap joints from pultruded GFRP profiles. Part I: stress–strain analysis and failure modes  

Microsoft Academic Search

Quasi-static axial tension experiments were performed in a laboratory environment on epoxy bonded, balanced double-lap and single-lap joints from pultruded GFRP flat sections. Full-scale specimens were used to avoid size effects. Parameters investigated were the overlap length (from 50 to 200mm), the adhesive layer thickness (from 1 to 3mm) and the adherend thickness (from 3 to 12mm). On nine of

Thomas Keller; Till Vallée

2005-01-01

146

An experimental study of the insert joint strength of composite sandwich structures  

Microsoft Academic Search

This paper addresses an experimental study of the pull-out and shear failure loads of composite sandwich insert joints. For specimen fabrication, a Nomex honeycomb core and a carbon–epoxy composite were used. The film-type adhesive FM73 was used for core and face co-cured bonding. Specimen sizes are 120×120mm2 for the pull-out test and 60×120mm2 for the shear loading test. About 80

Keun-Il Song; Ji-Young Choi; Jin-Hwe Kweon; Jin-Ho Choi; Kwang-Soo Kim

2008-01-01

147

Numerical analysis of mechanical testing for evaluating shear strength of SiC\\/SiC composite joints  

Microsoft Academic Search

As examples of the most typical methods to determine the shear strength of SiC\\/SiC composite joints, the asymmetrical four point bending test of a butt-joined composite, the tensile test of a lap-joined composite, and the compression test of a double-notched composite joint were analyzed by using a finite element method with the interface element. From the results, it was found

H. Serizawa; D. Fujita; C. A. Lewinsohn; M. Singh; H. Murakawa

2007-01-01

148

Challenges and Opportunities in Design, Fabrication, and Testing of High Temperature Joints in Ceramics and Ceramic Composites  

NASA Technical Reports Server (NTRS)

Ceramic joining has been recognized as an enabling technology for successful utilization of advanced ceramics and composite materials. A number of joint design and testing issues have been discussed for ceramic joints in silicon carbide-based ceramics and fiber-reinforced composites. These joints have been fabricated using an affordable, robust ceramic joining technology (ARCJoinT). The microstructure and good high temperature mechanical capability (compressive and flexural strengths) of ceramic joints in silicon carbide-based ceramics and composite materials are reported.

Singh, M.; Levine, S. R. (Technical Monitor)

2001-01-01

149

Diagnosis of Sacroiliac Joint Pain: Validity of individual provocation tests and composites of tests  

Microsoft Academic Search

Previous research indicates that physical examination cannot diagnose sacroiliac joint (SIJ) pathology. Earlier studies have not reported sensitivities and specificities of composites of provocation tests known to have acceptable inter-examiner reliability. This study examined the diagnostic power of pain provocation SIJ tests singly and in various combinations, in relation to an accepted criterion standard. In a blinded criterion-related validity design,

Mark Laslett; Charles N. Aprill; Barry McDonald; Sharon B. Young

2005-01-01

150

Alterations in mineral composition observed in osteoarthritic joints of cynomolgus monkeys  

Microsoft Academic Search

Osteoarthritis (OA) is a prevalent joint disease that affects more than 40 million Americans and is characterized by degeneration of the articular cartilage and thickening of the underlying subchondral bone. Although subchondral bone thickening has been implicated in articular cartilage degeneration, very little is known about the composition of subchondral bone in OA. In the present study, infrared microspectroscopy (IRMS)

Lisa M Miller; Jaclyn Tetenbaum Novatt; David Hamerman; Cathy S Carlson

2004-01-01

151

Impact induced composite delamination: state and parameter identification via joint and dual extended Kalman filters  

Microsoft Academic Search

We present and compare the joint and dual variants of the extended Kalman filter for coupled state and parameter identification problems. With reference to nonlinear dynamics of layered composites, we assume that the elastic properties of the laminae are known, whereas the softening constitutive law of the interlaminar phases adopted to simulate delamination needs to be calibrated. Purpose of this

Stefano Mariani; Alberto Corigliano

2005-01-01

152

Joint Composition: The Collaborative Letter Writing of a Scribe and His Client in Mexico.  

ERIC Educational Resources Information Center

Presents a detailed description of a scribe and his client in Mexico producing a letter through "joint composition," a term used to refer to letter-writing episodes involving two or more active participants. Shows how the participants negotiated their points of view and pooled their knowledge to produce a specific type of document. (PA)

Kalman, Judy

1996-01-01

153

Disbond monitoring in adhesive joints using shear stress optical fiber sensors  

NASA Astrophysics Data System (ADS)

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.

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

2014-07-01

154

Design/Analysis of Metal/Composite Bonded Joints for Survivability at Cryogenic Temperatures  

NASA Technical Reports Server (NTRS)

A major design and analysis challenge for the JWST ISM structure is the metal/composite bonded joints that will be required to survive down to an operational ultra-low temperature of 30K (-405 F). The initial and current baseline design for the plug-type joint consists of a titanium thin walled fitting (1-3mm thick) bonded to the interior surface of an M555/954-6 composite truss square tube with an axially stiff biased lay-up. Metallic fittings are required at various nodes of the truss structure to accommodate instrument and lift-point bolted interfaces. Analytical experience and design work done on metal/composite bonded joints at temperatures below liquid nitrogen are limited and important analysis tools, material properties, and failure criteria for composites at cryogenic temperatures are virtually nonexistent. Increasing the challenge is the difficulty in testing for these required tools and parameters at 30K. A preliminary finite element analysis shows that failure due to CTE mismatch between the biased composite and titanium or aluminum is likely. Failure is less likely with Invar, however an initial mass estimate of Invar fittings demonstrates that Invar is not an automatic alternative. In order to gain confidence in analyzing and designing the ISM joints, a comprehensive joint development testing program has been planned and is currently running. The test program is designed for the correlation of the analysis methodology, including tuning finite element model parameters, and developing a composite failure criterion for the effect of multi-axial composite stresses on the strength of a bonded joint at 30K. The testing program will also consider stress mitigation using compliant composite layers and potential strength degradation due to multiple thermal cycles. Not only will the finite element analysis be correlated to the test data, but the FEA will be used to guide the design of the test. The first phase of the test program has been completed and the preliminary analysis has been revisited based on the test data In this work, we present an overview of the test plan, results today, and resulting design improvements.

Bartoszyk, Andrew E.

2004-01-01

155

Anatomy of the rat knee joint and fibre composition of a major articular nerve.  

PubMed

Several recent reports discuss the role of joint nerves in arthritis. Many of these are based on studies in the rat. The aim of this study is to examine the anatomy of the rat knee joint, in search for a primary articular nerve, and to analyze the fibre composition of that nerve. The results show that the structure of the joint differs in some respects from the human knee. At the upper end of the bony patella a cartilaginous patella extends proximally, forming the anterior wall of the suprapatellar bursa. Distinct collateral ligaments are integrated in the joint capsule. The extensor digitorum longus muscle bridges the knee joint, originating from the lateral femoral epicondyle. The well-developed menisci contain pyramid-shaped ossicles. The cruciate ligaments are arranged like in the human knee. A large posterior (PAN) and a small medial (MAN) articular nerve can be identified. The PAN is composed of some 400 axons, about 80% of which are unmyelinated. All myelinated fibres are sensory. They present a unimodal size spectrum with a size range of 1-8 microns, and a predominance of small fibres. Specific denervations indicate that about 1/3 of the unmyelinated axons represent afferents, and some 2/3 are sympathetic efferents. Interestingly, neonatal capsaicin treatment did not influence the number of unmyelinated PAN axons. The functional significance of the numerous unmyelinated sympathetic and sensory PAN axons in the normal knee joint remains to be elucidated. PMID:2048758

Hildebrand, C; Oqvist, G; Brax, L; Tuisku, F

1991-04-01

156

An investigation of mechanical behavior and failure mechanisms of composite T-joints with transverse stitching  

NASA Astrophysics Data System (ADS)

A new low cost damage tolerant method of joining load-bearing composite structures using two-dimensional dry fabric preforms with transverse stitching and a novel fiber insertion process with resin transfer molding has recently been developed, however, knowledge of strength prediction and failure mechanisms is not well understood. In this investigation, fundamental knowledge of T-joint mechanical behavior was developed through detailed experimental, numerical, and post failure analyses. Experiments were conducted under flexure, tension, and shear loads and failed specimens were examined to discern failure modes. T-joint constituent elastic and strength properties were experimentally determined. Elastic properties were used as input to the finite element analysis and strength properties were used as limiting values in the T-joint failure analysis. Linear elastic, nonlinear elastic, and progressive damage finite element models were developed under each load condition. T-joint numerical models are shown to predict experimental behavior through ultimate load. Damage accumulation was characterized based on experimental, numerical, and post failure analyses. A parametric finite element analysis was conducted and design curves were derived to demonstrate the effect of varying key T-joint interface parameters on mechanical behavior under each load condition. Results of this research enable the application of T-joints with transverse stitching to future products and predictive finite element models developed herein reduce the structural testing required to validate these designs.

Stickler, Patrick Bickford

2001-07-01

157

An Innovative Joint Structure for Brazing Cf/SiC Composite to Titanium Alloy  

NASA Astrophysics Data System (ADS)

In view of aerospace applications, an innovative structure for joining a Ti alloy to carbon fiber reinforced silicon carbide has been developed. This is based on the perforation of the CMC material, and this procedure results in six-fold increase of the shear strength of the joint compared to the unprocessed CMC. The joint is manufactured using the active brazing technique and TiCuAg as filler metal. Sound joints without defects are produced and excellent wetting of both the composite ceramic and the metal is observed. The mechanical shear tests show that failure occurs always within the ceramic material and not at the joint. At the CMC/filler, Ti from the filler metal interacts with the SiC matrix to form carbides and silicides. In the middle of the filler region depletion of Ti and formation of Ag and Cu rich regions are observed. At the filler/Ti alloy interface, a layered structure of the filler and Ti alloy metallic elements is formed. For the perforation to have a significant effect on the improvement of the shear strength of the joint appropriate geometry is required.

Hernandez, X.; Jiménez, C.; Mergia, K.; Yialouris, P.; Messoloras, S.; Liedtke, V.; Wilhelmi, C.; Barcena, J.

2014-05-01

158

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

NASA Technical Reports Server (NTRS)

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.

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

1983-01-01

159

Experimental and numerical failure analysis of pinned-joints in composite materials  

Microsoft Academic Search

In this paper, failure load and failure mode of glass-epoxy composite plates with single and double parallel pinned-joints have analysed experimentally and numerically. Two variables were investigated during analyses; the distance from the free edge of plate to the diameter of the first hole (E\\/D) ratio (2, 3, 4, 5), and the width of the specimen to the diameter of

Alaattin Akta?; Hüseyin ?mrek; Yusuf Cunedio?lu

2009-01-01

160

Delamination damage analyses of adhesively bonded lap shear joints in laminated FRP composites  

Microsoft Academic Search

Three-dimensional non-linear finite ele- ment analyses have been carried out to evaluate the out-of-plane stresses in the\\u000a adhesive layer existing between the lap and the strap adherends of the Lap Shear Joint (LSJ) in laminated FRP composites for\\u000a varied delamination lengths. The delaminations are presumed to be pre-embedded in the thin resin rich layer existing between\\u000a the first and second

S. K. Panigrahi; B. Pradhan

2007-01-01

161

Fatigue crack growth in adhesively bonded composite-metal double-lap joints  

Microsoft Academic Search

This paper presents experimental and numerical investigations of the fatigue crack initiation and growth mechanism in metal-to-composite bonded double-lap joints. Fatigue tests were conducted under tension dominated loading, with crack lengths being measured optically. Examination of the fracture surface using scanning electron microscope revealed that fatigue cracks were near the interface between the co-cured adhesive and the first ply of

P. T Cheuk; L Tong; C. H Wang; A Baker; P Chalkley

2002-01-01

162

Fatigue failure characterisation of resistance-welded thermoplastic composites skin\\/stringer joints  

Microsoft Academic Search

An experimental investigation characterising the fatigue failure mechanisms of resistance-welded thermoplastic composites skin\\/stringer joints is presented. Unidirectional (UD) and quasi-isotropic adherends were welded using stainless steel meshes as heating elements. The specimen geometry consisted of a flange laminate, representing a stringer, welded onto a skin laminate. In order to avoid current leakage to the electrically conductive adherends, a ceramic-coated heating

M. Dubé; P. Hubert; A. Yousefpour; J. Denault

2009-01-01

163

Stress and failure analysis of mechanically fastened joints in composite laminates  

Microsoft Academic Search

The literature published on single mechanically fastened joints in fiber-reinforced plastics is reviewed. A finite-element model is developed to predict the response of pin-loaded composite plates. The model takes into account contact at the pin–hole interface, progressive damage, large deformation theory, and a non-linear shear stress–strain relationship. To predict the progressive ply failure, the analysis combines Hashin and the maximum

Marie-Laure Dano; Guy Gendron; André Picard

2000-01-01

164

Bolted Double-Lap Composite Joints Under Mechanical and Thermal Loading  

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

165

Fatigue in mechanically fastened composite and metallic joints; Proceedings of the Symposium, Charleston, SC, Mar. 18, 19, 1985  

SciTech Connect

The present conference considers advanced fastener technology for composite and metallic joints, a fatigue life-enhancing and high interference bushing installation employing the 'ForceMate' technique, fatigue life improvement by cold working fastener holes in 7050 aluminum alloy, the fatigue strength of bolted and adhesively bonded structural steel joints, and the effect of load transfer on the fatigue of mechanically fastened metallic joints. Also discussed are the evaluation of a stochastic initial fatigue quality model for fastener holes, the experimental characterization of cracks at open holes and in rounded-end straight attachment lugs, the fatigue of riveted metallic joints, an enhanced stop-drill repair procedure for cracked structures, the influence of fastener flexibility on load transfer and fatigue life prediction in multiple row joints, the strength and lifetime of bolted laminates, and the fatigue of bolted continuous-fiber/sheet-molding-compound composite-metal joints.

Potter, J.M.

1986-01-01

166

The Effect of Composite Patches on the Failure of Adhesively-Bonded Joints Under Bending Moment  

NASA Astrophysics Data System (ADS)

In this study, it was aimed to compare mechanical behavior of double-strap joints with aluminum (AA2024-T3) or 16-ply laminate of carbon/epoxy composite (T300/934) patches of different orientation angles at their overlap area subjected to bending moment. For this purpose, AA2024-T3 aluminum was used as adherend, while the adhesive was a two-part paste (DP 460). Six different types of joint samples were subjected to bending moment. The effect of patch material on failure load and stress distribution was examined experimentally and numerically. In the numerical analysis, the composite patches were assumed to behave linearly elastic, while adherend and adhesive layers were assumed to be nonlinear. It was found that the data obtained from 3-D finite element analysis were coherent with experimental results. Meanwhile, experiments showed that fiber orientation angles of the patches markedly affected the failure load of joints, failure mode and stress distributions appeared in adhesive and composite.

Akpinar, Salih

2013-12-01

167

The effect of joint design and volume fraction on friction welding properties of A360\\/SiC(p) composites  

Microsoft Academic Search

This research uses a rotation friction welding system with 360Al and 360Al\\/5v-%-10v-% (v-% = volume fraction percent) SiC particulate composites utilizing both identical and different materials and two joint designs. In joint design 1, one side is a lead angle and the other is a plane. In joint design 2, both sides are planes. From the experiment, it was noted

C. B. Lin; C. K. Mu; W. W. Wu; C. H. Hung

1999-01-01

168

Transfer of a composite island homodigital distal interphalangeal joint to replace the proximal interphalangeal joint. Technique and case report.  

PubMed

The authors present an original technique of PIP joint reconstruction by an homo-digital island compound DIP joint transfer. The transfer consists of joint, capsule, volar plate, and ligaments. The distal joint is fused and the islanded joint interposed at the PIP level. In our clinical case, a flexion of 80 degrees was obtained with an extension lack of 15 degrees. This salvage procedure can be useful in selected well motivated patients. It provides rapid bone healing, good lateral stability, potential for growth in children, long term preservation of cartilage and acceptable range of motion. PMID:1705134

Foucher, G; Lenoble, E; Sammut, D

1990-01-01

169

Combined In-Plane and Through-the-Thickness Analysis for Failure Prediction of Bolted Composite Joints.  

National Technical Information Service (NTIS)

Although two-dimensional methods provide accurate predictions of contact stresses and bolt load distribution in bolted composite joints with multiple bolts, they fail to capture the effect of thickness on the strength prediction. Typically, the plies clos...

V. Kradinov E. Madenci D. R. Ambur

2004-01-01

170

Three-dimensional finite element analysis of double-lap composite adhesive bonded joint using submodeling approach  

Microsoft Academic Search

Three-dimensional stress analysis is performed for double-lap composite-to-composite adhesive bonded joint exposed to uniaxial extension. The submodeling approach using 27-node solid element available in the recent versions of abaqus is utilized. Principal objectives are: to explore computational advantages provided by the multi-step submodeling approach and perform a comprehensive numerical study of three-dimensional (3D) stress variations in the joint structure, considering

A. E. Bogdanovich; I. Kizhakkethara

1999-01-01

171

Seismic Retrofit of Reinforced Concrete Beam Column T-Joints in Bridge Piers with FRP Composite Jackets  

Microsoft Academic Search

Synopsis: The research described encompasses laboratory as well as in-situ testing of reinforced concrete beam-column joints and multicolumn bridge piers rehabilitated with FRP composite jackets. Fourteen RC beam-column joint tests were performed and a design equation was developed which determines the thickness of the FRP composite jacket and the orientation of the fibers for maximum effectiveness in enhancing shear capacity

C. P. Pantelides; J. Gergely

172

Design, fabrication and test of graphite/polymide composite joints and attachments: Summary  

NASA Technical Reports Server (NTRS)

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 561K (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 589K (600 F)) and thermal cycled (116K to 589K (-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 589K (600 F) for 125 hours.

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

1983-01-01

173

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

NASA Technical Reports Server (NTRS)

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.

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

1982-01-01

174

Mixed-mode cyclic debonding of adhesively bonded composite joints. M.S. Thesis  

NASA Technical Reports Server (NTRS)

A combined experimental-analytical investigation to characterize the cyclic failure mechanism of a simple composite-to-composite bonded joint is conducted. The cracked lap shear (CLS) specimens of graphite/epoxy adherend bonded with EC-3445 adhesive are tested under combined mode 1 and 2 loading. In all specimens tested, fatigue failure occurs in the form of cyclic debonding. The cyclic debond growth rates are measured. The finite element analysis is employed to compute the mode 1, mode 2, and total strain energy release rates (i.e., GI, GII, and GT). A wide range of mixed-mode loading, i.e., GI/GII ranging from 0.03 to 0.38, is obtained. The total strain energy release rate, G sub T, appeared to be the driving parameter for cyclic debonding in the tested composite bonded system.

Rezaizadeh, M. A.; Mall, S.

1985-01-01

175

Analytical and Numerical Results for an Adhesively Bonded Joint Subjected to Pure Bending  

NASA Technical Reports Server (NTRS)

A one-dimensional, semi-analytical methodology that was previously developed for evaluating adhesively bonded joints composed of anisotropic adherends and adhesives that exhibit inelastic material behavior is further verified in the present paper. A summary of the first-order differential equations and applied joint loading used to determine the adhesive response from the methodology are also presented. The method was previously verified against a variety of single-lap joint configurations from the literature that subjected the joints to cases of axial tension and pure bending. Using the same joint configuration and applied bending load presented in a study by Yang, the finite element analysis software ABAQUS was used to further verify the semi-analytical method. Linear static ABAQUS results are presented for two models, one with a coarse and one with a fine element meshing, that were used to verify convergence of the finite element analyses. Close agreement between the finite element results and the semi-analytical methodology were determined for both the shear and normal stress responses of the adhesive bondline. Thus, the semi-analytical methodology was successfully verified using the ABAQUS finite element software and a single-lap joint configuration subjected to pure bending.

Smeltzer, Stanley S., III; Lundgren, Eric

2006-01-01

176

Numerical analysis of mechanical testing for evaluating shear strength of SiC/SiC composite joints  

NASA Astrophysics Data System (ADS)

As examples of the most typical methods to determine the shear strength of SiC/SiC composite joints, the asymmetrical four point bending test of a butt-joined composite, the tensile test of a lap-joined composite, and the compression test of a double-notched composite joint were analyzed by using a finite element method with the interface element. From the results, it was found that the shear strength in the asymmetrical bending test was controlled by both the surface energy and the shear strength at the interface regardless of their combination while the strength in the tensile test or the compression test was governed by the surface energy when both the surface energy and the shear strength were large. Also, the apparent shear strength of the composite joint obtained experimentally appeared to be affected by the combination of the surface energy and the shear strength at the interface.

Serizawa, H.; Fujita, D.; Lewinsohn, C. A.; Singh, M.; Murakawa, H.

2007-08-01

177

The effect of joint design and volume fraction on friction welding properties of A360/SiC(p) composites  

SciTech Connect

This research uses a rotation friction welding system with 360Al and 360Al/5v-%-10v-% (v-% = volume fraction percent) SiC particulate composites utilizing both identical and different materials and two joint designs. In joint design 1, one side is a lead angle and the other is a plane. In joint design 2, both sides are planes. From the experiment, it was noted that using joint design 1 achieved better joint strength. The joint strength is best with 360Al-360Al and worst with 360Al/10v-%-360Al/10v-% SiC particulate composites. 360Al-360Al has a ductile fracture with dimples, while the 360Al/10v-%-360Al/10v-% SiC particulate composite has a low-ductile fracture. The 360Al/10v-%-360Al/10v-% SiC particulate composites are fractured in the Zpl zone, while the others are fractured in the interface between the Zpl zone and the Zpd zone. For the joint systems using different materials, the fracture is in the interface between the Zpl zone and Zpd zone, where the quantity of SiC particulate is higher. In the heat-affected zone (HAZ) for identical materials, the Zpl hardness value is smaller than Zud; for the different materials, the hardness in Zpl is half of the two Zud hardness total values.

Lin, C.B.; Mu, C.K.; Wu, W.W.; Hung, C.H. [Tamkang Univ. (Taiwan, Province of China). Dept. of Mechanical Engineering

1999-03-01

178

Probabilistic Simulation of Progressive Fracture in Bolted-Joint Composite Laminates  

NASA Technical Reports Server (NTRS)

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.

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

1996-01-01

179

An experimental study on fatigue life of interference-fit composite joint  

NASA Astrophysics Data System (ADS)

An experimental study on fatigue life of an interference-fit composite joint is presented. The experimental results show that suitable interference can increase fatigue life in comparison with the push-fit case. For the material and the laying studied, when the interference is 2 percent, the fatigue life is increased 2-3 times. An explanation for the result is given. In order to obtain the current result, some methods of processing and assembling are emphasized in the experiment. An explanation is given for the definition of fatigue life limitation and the choice of the best interference.

Liu, Ping; Zhang, Kaida

1991-12-01

180

Interaction of mixed mode loading on cyclic debonding in adhesively bonded composite joints  

NASA Technical Reports Server (NTRS)

A combined experimental and analytical investigation of an adhesively-bonded composite joint was conducted to characterize the fracture mode dependence of cyclic debonding. The system studied consisted of graphite/epoxy adherends bonded with EC 3445 adhesive. Several types of specimens are tested which provide the cyclic debond growth rate measurements under various load conditions: mode 1, mixed mode 1 to 2, and mostly mode 2. This study shows that the total strain-energy-release rate is the governing factor for cyclic debonding.

Mall, S.; Rezaizadeh, M. A.; Ramamurthy, G.

1985-01-01

181

Experimental structural health monitoring of Z-fibre reinforced co-cured composite pi-joints using Lamb wave propagation  

Microsoft Academic Search

The goal of this research is to establish a methodology for damage detection in unreinforced and z-fiber reinforced cocured composite pi- joints using lamb wave based structural health monitoring technique. Because of the lack of natural reinforcement in the thickness direction, delamination has been a predominant failure mode besides other failure modes in laminated composites. Z-fiber reinforcement is one of

Hitesh Kapoor; Som R. Soni

2009-01-01

182

Design of low residual stress joints between 3D CC composites and Glidcop copper for divertor applications  

NASA Astrophysics Data System (ADS)

An innovative approach to modeling the interfacial residual stress between CC Composites and Glidcop copper is proposed. The model predictions were consistent with experimental observations in ceramic-metal joints where it was easier to visualize cracking, and later extended to carbon-Glidcop copper joints. A variety of interface designs were investigated. The numerical predictions were consistent with experimental results in the Glidcop-ISO63 graphite system but less consistent in the C?C composite-Glidcop copper system. This inconsistency is presently attributed to the inhomogeneous nature of C?C composite in contrast to ISO63 graphite or Si 3N 4 ceramic. A joint design based on the numerical results, comprising of grooves in the Glidcop copper and metallic interlayers appeared to alleviate the residual stresses sufficiently enough to allow bonding between C?C composite and Glidcop copper.

Guha, Sumit; Kiousis, Panos; Loutfy, Raouf; Watson, Robert D.

1995-03-01

183

The study of lifetime of polymer and composite bone joint screws under cyclical loads and in vitro conditions  

Microsoft Academic Search

The “strain-life time” method has been adapted for life-time prediction of polymer and composite bone joint screws. Mechanical\\u000a and fatigue properties of screws made of biostable (polysulfone), biosorbable (poly(lactide-co-glycolide) and short carbon\\u000a fibre reinforced polymer composite materials have been examined in this study. The lifetime predictions under in vitro conditions were calculated for polymer and composite implants. The forecasting of

Ch?opek Jan; Kmita Grzegorz

2005-01-01

184

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

NASA Astrophysics Data System (ADS)

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.

Pucinotti, Raffaele; Ferrario, Fabio; Bursi, Oreste S.

2008-07-01

185

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

SciTech Connect

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.

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

186

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

187

Test results for composite specimens and elements containing joints and cutouts  

NASA Technical Reports Server (NTRS)

A program was conducted to develop the technology for joints and cutouts in a composite fuselage that meets all design requirements of a large transport aircraft for the 1990s. An advanced trijet derivative of the DC-10 was selected as the baseline aircraft. Design and analysis of a 30-foot-long composite fuselage barrel provided a realistic basis for the test effort. The primary composite material was Hexcel F584 resin on 12 K IM6 fiber, in tape and broadgoods form. Fiberglass broadgoods were used in E-glass and S-glass fiber form in the cutout region of some panels. Additionally, injection-molded chopped graphite fiber/PEEK was used for longeron-to-frame shear clips. The test effort included four groups of test specimens, beginning with coupon specimens of mono-layer and cross-piled laminates, progressing through increasingly larger and more complex specimens, and ending with two 4- by 5-foot curved fuselage side panels. One of the side panels incorporated a transverse skin splice, while the second included two cabin window cutouts.

Sumida, P. T.; Madan, R. C.; Hawley, A. V.

1988-01-01

188

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

NASA Technical Reports Server (NTRS)

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.

Lineberger, L. B.

1984-01-01

189

Guided-wave-based damage detection in a composite T-joint using 3D scanning laser Doppler vibrometer  

NASA Astrophysics Data System (ADS)

Composite T-joints are commonly used in modern composite airframe, pressure vessels and piping structures, mainly to increase the bending strength of the joint and prevents buckling of plates and shells, and in multi-cell thin-walled structures. Here we report a detailed study on the propagation of guided ultrasonic wave modes in a composite T-joint and their interactions with delamination in the co-cured co-bonded flange. A well designed guiding path is employed wherein the waves undergo a two step mode conversion process, one is due to the web and joint filler on the back face of the flange and the other is due to the delamination edges close to underneath the accessible surface of the flange. A 3D Laser Doppler Vibrometer is used to obtain the three components of surface displacements/velocities of the accessible face of the flange of the T-joint. The waves are launched by a piezo ceramic wafer bonded on to the back surface of the flange. What is novel in the proposed method is that the location of any change in material/geometric properties can be traced by computing a frequency domain power flow along a scan line. The scan line can be chosen over a grid either during scan or during post-processing of the scan data off-line. The proposed technique eliminates the necessity of baseline data and disassembly of structure for structural interrogation.

Kolappan Geetha, Ganesh; Roy Mahapatra, D.; Srinivasan, Gopalakrishnan

2012-03-01

190

Design aid for shear strengthening of reinforced concrete T-joints using carbon fiber reinforced plastic composites  

NASA Astrophysics Data System (ADS)

The research presented in the present work focuses on the shear strengthening of beam column joints using carbon fiber composites, a material considered in seismic retrofit in recent years more than any other new material. These composites, or fiber reinforced polymers, offer huge advantages over structural steel reinforced concrete or timber. A few of these advantages are the superior resistance to corrosion, high stiffness to weight and strength to weight ratios, and the ability to control the material's behavior by selecting the orientation of the fibers. The design and field application research on reinforced concrete cap beam-column joints includes analytical investigations using pushover analysis; design of carbon fiber layout, experimental tests and field applications. Several beam column joints have been tested recently with design variables as the type of composite system, fiber orientation and the width of carbon fiber sheets. The surface preparation has been found to be critical for the bond between concrete and composite material, which is the most important factor in joint shear strengthening. The final goal of this thesis is to develop design aids for retrofitting reinforced concrete beam column joints. Two bridge bents were tested on the Interstate-15 corridor. One bent was tested in the as-is condition. Carbon fiber reinforced plastic composite sheets were used to externally reinforce the second bridge bent. By applying the composite, the displacement ductility has been doubled, and the bent overall lateral load capacity has been increased as well. The finite element model (using DRAIN-2DX) was calibrated to model the actual stiffness of the supports. The results were similar to the experimental findings.

Gergely, Ioan

191

The cyclic fatigue behavior of adhesive joints  

NASA Astrophysics Data System (ADS)

In the last six months we have: (1) Concentrated our efforts on the fatigue failure of carbon-fiber PEEK/AFl63 lap joints, and in particular we have started to predict the life time of single-lap joints under cyclic fatigue loading. The analysis is based on data obtained from double cantilever beam (DCB) fracture mechanics tests; (2) Further, we have been successful in measuring the rate of crack growth in lap joints during fatigue fracture using ultrasonic scanning; (3) Preliminary test data on the static fracture of glass-fiber reinforced poly(phenylene sulphide) (PPS)/AF163 joints have also been studied; and (4) A comparison has been made in computing the critical strain energy release rate G(sub c) for the glass-fiber PPS/AF163 joints based on the compliance method, beam theory and corrected beam theory. The last method accounts for large non-linear deflections and the associated crack root rotations along with the necessary corrections for the increase in stiffness introduced by the presence of end blocks.

Kinloch, A. J.; Toh, T.

1995-06-01

192

An inelastic analysis methodology for bonded joints with shear deformable, anisotropic adherends  

NASA Astrophysics Data System (ADS)

The development of a one-dimensional analysis method for evaluating adhesively bonded joints composed of anisotropic adherends and adhesives that exhibit nonlinear material behavior is presented. The strain and resulting stress field in a general, bonded joint overlap are determined by using a variable-step, finite-difference solution algorithm to iteratively solve a system of first-order differential equations. Applied loading is given by a system of combined extensional, bending, and shear loads that are applied to the edge of the joint overlap. Adherends are assumed to behave as linear, cylindrically-bent plates using classical laminated plate theory that includes the effects of first-order transverse shear deformation. This provides a capability for modeling differences in the transverse shear modulus between each adherend. Using the deformation theory of plasticity and a modified von-Mises yield criterion, inelastic material behavior is modeled in the adhesive layer. Results for the proposed method are verified using the single-lap joint geometry against previous results from the literature and shown to be in excellent agreement. Convergence of the strain and stress fields determined using the finite-difference solver are described as a function of the number of evaluation points along the length of the joint. Additionally, design studies using the single-lap joint are presented that investigate the effects of changes to the joint overlap, adherend thickness, laminate stacking sequence of the adherend, adherend material properties, and adhesive material properties. Results from the design studies established a nonlinear relationship between changes in the bending and axial stiffness of the adherends due to laminate ply manipulations and a reduction in the inelastic adhesive strain and shear stress responses. Additionally, a minimal effect on the adhesive strain and stress responses was demonstrated by the results from the bonded joint models that had a difference between the transverse shear stiffness of the upper and lower adherends.

Smeltzer, Stanley S., III

2003-06-01

193

Thermal analysis for resistance welding of large-scale thermoplastic composite joints  

NASA Astrophysics Data System (ADS)

The need for effective and reliable joining methods continues to grow as the use of thermoplastic composites becomes widespread. It is now possible to join large-scale components with the development of an automated sequential resistance welding process. The thermal history generated by the heating element placed at the interface between adherends determines the quality and performance of the welded joint. This article presents a thermal analysis for the resistance welding of large-scale components that overcomes the limitations of previous models. To simulate welding of the interface, a heat generation term was incorporated that accounts for the Joule heating of graphite fibers in the heating element. A parametric study was conducted to investigate the influence of welding parameters and assess the uniformity of interface temperatures. Components were joined by the resistance welding process to obtain experimental verification. Regions of localized overheating where potential current leakage may occur were identified as a function of process parameters. Insights on promoting more uniform heating for the resistance welding process are discussed.

Holmes, Scott T.; Gillespie, John W., Jr.

1993-06-01

194

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

SciTech Connect

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.

Darsell, Jens T.; Weil, K. Scott

2008-09-08

195

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

NASA Technical Reports Server (NTRS)

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.

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

1982-01-01

196

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

NASA Technical Reports Server (NTRS)

The design and evaluation of built-up attachments and bonded joint concepts for use at elevated temperatures is documented. Joint concept screening, verification of GR/PI material, fabrication of design allowables panels, definition of test matrices, and analysis of bonded and bolted joints are among the tasks completed. The results provide data for the design and fabrication of lightly loaded components for advanced space transportation systems and high speed aircraft.

Koumal, D. E.

1979-01-01

197

The use of a cohesive zone model to study the fracture of fibre composites and adhesively-bonded joints  

Microsoft Academic Search

Analytical solutions for beam specimens used in fracture-mechanics testing of composites and adhesively-bonded joints typically\\u000a use a beam on an elastic foundation model which assumes that a non-infinite, linear-elastic stiffness exists for the beam\\u000a on the elastic foundation in the region ahead of the crack tip. Such an approach therefore assumes an elastic-stiffness model\\u000a but without the need to assume

B. R. K. Blackman; H. Hadavinia; A. J. Kinloch; J. G. Williams

2003-01-01

198

Creep measurements on SnAgCu solder joints in different compositions and after mechanical and thermal treatment  

Microsoft Academic Search

Solder joints are still the main conductor element between electronic components and carrier substrates. The visco-plastic behaviour of the particle strengthened SnAgCu solder alloys depends strongly on its composition. Additionally, the mechanical behaviour is influenced by solder condition after the soldering reflow process. Further influencing factors are dissolution of metal from the connection pad area, cooling rate, volume, thermal or

Mike Röllig; Steffen Wiese; Karsten Meier; Klaus-Jürgen Wolter

2008-01-01

199

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

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

200

Electromigration and thermomigration studies in composite high lead and eutectic tin-lead flip chip solder joint  

NASA Astrophysics Data System (ADS)

The effect of thermomigration and the combination effect of thermomigration and electromigration have been studied in composite SnPb flip chip solder joints. Because Al line on the silicon chip side is the major heat source exerted on flip chip solder joint, temperature gradient across the joint is induced when a long Al line is stressed with high current density. Under a estimated temperature gradient of 1000°C/cm, Sn-rich and Pb-rich phase separation is found to occur. Experimental results have shown that Sn-rich phase accumulates at the hot side and Pb-rich phase accumulates at the cold side after thermomigration. When solder bumps are current high current density, thermomigration was found to accompany electromigration. Not only Pb-rich phase migrated toward the anode side and Sn-rich phase migrated toward the cathode side due to electromigration, Sn-rich phase was found to migrate along the top of solder joint due to thermomigration. It was found that as void propagates along the top of the solder joint, current crowding region shifts with the tip of the void. This created a local hot spot and thus a lateral temperature gradient was induced for thermomigration to occur. To isolate the thermal effect from the current effect, ac stressing at 60 Hz was also utilized. Interestingly, ac seems to have an effect other than thermal effect due to the difference in microstructure evolution between pure thermomigration and ac case after stressing. Further investigation at different frequency is needed to fully understand the effect of ac. Furthermore, analysis was performed to explain the phenomena of phase separation and phase reversal in the solder joint considering a constraint volume within underfill. Both Kirkendall effect and back stress were considered. Finally, detail morphological change after thermomigration and electromigration were investigated. Grain refinement was found to occur at a certain stressing condition. Production of entropy and morphological instability were utilized to explain the phenomenon.

Huang, Annie Tzuyu

201

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

NASA Technical Reports Server (NTRS)

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.

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

1985-01-01

202

Stresses in adhesively bonded joints - A closed-form solution  

NASA Technical Reports Server (NTRS)

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.

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

1981-01-01

203

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

NASA Technical Reports Server (NTRS)

Bonded and bolted designs are presented for each of four major attachment types. Prepreg processing problems are discussed and quality control data are given for lots 2W4604, 2W4632 and 2W4643. Preliminary design allowables test results for tension tests and compression tests of laminates are included. The final small specimen test matrix is defined and the configuration of symmetric step-lap joint specimens are shown. Finite element modeling studies of a double lap joint were performed to evaluate the number of elements required through the adhesive thickness to assess effects of various joint parameters on stress distributions. Results of finite element analyses assessing the effect of an adhesive fillet on the stress distribution in a double lap joint are examined.

Skoumal, D. E.

1980-01-01

204

Effects of Carbon Nanomaterial Reinforcement on Composite Joints Under Cyclic and Impact Loading.  

National Technical Information Service (NTIS)

This study investigated the influence of Multi-Walled Carbon Nanotubes (MWCNTs) and Carbon Nanofibers (CNFs) reinforcement on the behavior of Carbon Fiber Reinforced Polymer (CFRP) joint interface under cyclic and impact loading. Test coupons with pre-cra...

M. H. Tan

2012-01-01

205

Mechanical properties and microstructure of 2.5D (shallow straight-joint) quartz fibers-reinforced silica composites by silicasol-infiltration-sintering  

Microsoft Academic Search

2.5D (shallow straight-joint) quartz fibers-reinforced silica composites were successfully prepared by silicasol-infiltration-sintering method. The composites were sintered at 450°C and the density of the composite was up to 1.70g\\/cm3 after 11 infiltration-sintering cycles. The characteristics of 2.5D (shallow straight-joint) structure were determined. Flexural strength and shear strength of the composites were investigated along the warp and weft directions. The undulation

Yong Liu; Jianxun Zhu; Zhaofeng Chen; Yun Jiang; Chengdong Li; Binbin Li; Long Lin; Tianru Guan; Zhaohai Chen

206

Experimental Behaviour of Exterior Beam-Column Joint Subassemblies Retrofitted Using GFRP Composites  

Microsoft Academic Search

Most of the experimental studies available in the literature on the seismic behaviour of poorly detailed beam-column joint subassemblies prior to and after retrofit intervention have concentrated on the 2-dimensional response, thus subjecting the specimen to uni-directional cyclic loading. In addition, the attention has been typically given to interior (fully or partially confined) beam-column joint subassemblies, with limited information on

S. Pampanin

207

Experimental study of RC beam–column joints strengthened using CFRP composites  

Microsoft Academic Search

This paper presents an experimental study to strengthen the shear capacity of non-seismic joints using Carbon Fiber Reinforced Plastic (CFRP) materials. Eight exterior RC beam–column joint specimens including a non-seismic specimen, a seismic specimen and six retrofitted specimens with different configurations of CFRP sheets were developed and tested to find out an effective way to improve the seismic performance of

Kien Le-Trung; Kihak Lee; Jaehong Lee; Do Hyung Lee; Sungwoo Woo

2010-01-01

208

Reliability aspects of a composite bolted scarf joint. [in wing skin splice  

NASA Technical Reports Server (NTRS)

The design, fabrication, static test, and fatigue test of both tension and compression graphite-epoxy candidates for a wing splice representative of a next-generation transport aircraft was the objective of the reported research program. A single-scarf bolted joint was selected as the design concept. Test specimens were designed and fabricated to represent an upper-surface and a lower-surface panel containing the splice. The load spectrum was a flight-by-flight random-load history including ground-air-ground loads. The results of the fatigue testing indicate that, for this type of joint, the inherent fatigue resistance of the laminate is reflected in the joint behavior and, consequently, the rate of damage accumulation is very slow under realistic fatigue loadings.

Reed, D. L.; Eisenmann, J. R.

1975-01-01

209

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)

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.

Singh, M.; Asthana, R.

2008-01-01

210

Experimental and numerical failure analysis of carbon\\/epoxy laminated composite joints under different conditions  

Microsoft Academic Search

The aim of this study is to investigate the effects of preload moment, moisture and interference-fit on bearing strength and failure mode in pin-jointed and bolted carbon–epoxy plates which were subjected to a traction force. Two different geometrical parameters, end distance to pin diameter ratio (E\\/D) and width to pin diameter ratio (W\\/D), were considered experimentally. E\\/D and W\\/D ratios

Servet Kapti; Onur Sayman; Mustafa Ozen; Semih Benli

2010-01-01

211

PERFORMANCE OF CORNER RC BEAM-COLUMN JOINTS UP GRADED WITH CFRP COMPOSITES UNDER SEISMIC LOADING  

Microsoft Academic Search

In the last four decades several research papers have been published on the effect of seismic loads on poorly detailed reinforced concrete beam-column joints, typical of pre-seismic code designed moment resisting frames (1-5). A detailed review of literature shows that systematic studies to deter- mine the behavior of the FRP repaired\\/upgraded members under cyclic loading are still limited. More- over,

Saleh H. ALSAYED; Yousef A. AL-SALLOUM; Tarek H. ALMUSALLAM; Nadeem A. SIDDIQUI

212

A Progressive Damage Model for Mechanically Fastened Joints in Composite Laminates  

Microsoft Academic Search

A three-dimensional finite element model is developed to predict damage progression and strength of mechanically fastened joints in carbon fibre-reinforced plastics that fail in the bearing, tension and shear-out modes. The model is based on a three-dimensional finite element model, on a three-dimensional failure criterion and on a constitutive equation that takes into account the effects of damage on the

P. P. Camanho; F. L. Matthews

1999-01-01

213

High density polyethylene/graphite nano-composites for total hip joint replacements: processing and in vitro characterization.  

PubMed

The main objective of the present study is to investigate how the thermal, rheological, mechanical and cytotoxicity behavior of High Density Polyethylene (HDPE) can be changed by the addition of graphite nano particles (GNPs) at different contents. The HDPE/GNPs composites were prepared using melt blending in a co-rotating intermeshing twin screw extruder. The in vitro tests results showed that the original material (HDPE) and all HDPE/GNPs composites do not exhibit any cytotoxicity to the WISH cell line. The microscopic examination of the nano-composite tensile-fractured surface found a good distribution of GNPs in the HDPE matrix. The Differential Scanning Calorimetry (DSC) results indicated that the crystallization percentage increased by adding GNPs to HDPE up to 4%. The XRD patterns of the HDPE/GNPs composites showed an increase in peak intensity compared to neat HDPE. This increase echoed the crystallinity results obtained from DSC. The rheological tests showed that the complex viscosity of the HDPE increased as the percentage of GNPs increased due to the restriction of the molecular mobility. The tensile test results showed that with increasing the GNPs content, Young's modulus and the yield strength of the HDPE/GNPs composite increased while the strain at fracture decreased. Finally, the preliminary results of the abrasion test indicated that the abrasion rate decreased by increasing the GNPs ratio up to 4% content. The prepared HDPE/GNPs composites appear to have fairly good comprehensive properties that make them a good candidate as a bearing material for the total joint replacement. PMID:21783148

Fouad, H; Elleithy, Rabeh

2011-10-01

214

Combined In-Plane and Through-the-Thickness Analysis for Failure Prediction of Bolted Composite Joints  

NASA Technical Reports Server (NTRS)

Although two-dimensional methods provide accurate predictions of contact stresses and bolt load distribution in bolted composite joints with multiple bolts, they fail to capture the effect of thickness on the strength prediction. Typically, the plies close to the interface of laminates are expected to be the most highly loaded, due to bolt deformation, and they are usually the first to fail. This study presents an analysis method to account for the variation of stresses in the thickness direction by augmenting a two-dimensional analysis with a one-dimensional through the thickness analysis. The two-dimensional in-plane solution method based on the combined complex potential and variational formulation satisfies the equilibrium equations exactly, and satisfies the boundary conditions and constraints by minimizing the total potential. Under general loading conditions, this method addresses multiple bolt configurations without requiring symmetry conditions while accounting for the contact phenomenon and the interaction among the bolts explicitly. The through-the-thickness analysis is based on the model utilizing a beam on an elastic foundation. The bolt, represented as a short beam while accounting for bending and shear deformations, rests on springs, where the spring coefficients represent the resistance of the composite laminate to bolt deformation. The combined in-plane and through-the-thickness analysis produces the bolt/hole displacement in the thickness direction, as well as the stress state in each ply. The initial ply failure predicted by applying the average stress criterion is followed by a simple progressive failure. Application of the model is demonstrated by considering single- and double-lap joints of metal plates bolted to composite laminates.

Kradinov, V.; Madenci, E.; Ambur, D. R.

2004-01-01

215

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

SciTech Connect

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.

Bakosi, Jozsef [Los Alamos National Laboratory

2010-01-01

216

Construction of tissue-engineered osteochondral composites and repair of large joint defects in rabbit.  

PubMed

In this study, a novel three-dimensional (3D) heterogeneous/bilayered scaffold was constructed to repair large defects in rabbit joints. The scaffold includes two distinct but integrated layers corresponding to the cartilage and bone components. The upper layer consists of gelatin, chondroitin sulphate and sodium hyaluronate (GCH), and the lower layer consists of gelatin and ceramic bovine bone (GCBB). The two form a 3D bilayered scaffold (GCH-GCBB), which mimics the natural osteochondral matrix for use as a scaffold for osteochondral tissue engineering. The purpose of this study was to evaluate the efficacy of this novel scaffold, combined with chondrocytes and bone marrow stem cells (BMSCs) to repair large defects in rabbit joints. Thirty-six large defects in rabbit femoral condyles were created; 12 defects were treated with the same scaffold combined with cells (group A); another 12 defects were treated with cell-free scaffolds (group B); the others were untreated (group C). At 6 and 12?weeks, in group A hyaline-like cartilage formation could be observed by histological examination; the newly formed cartilage, which stained for type II collagen, was detected by RT-PCR at high-level expression. Most of the GCBB was replaced by bone, while little remained in the underlying cartilage. At 36?weeks, GCBB was completely resorbed and a tidemark was observed in some areas. In contrast, groups B and C showed no cartilage formation but a great amount of fibrous tissue, with only a little bone formation. In summary, this study demonstrated that a novel scaffold, comprising a top layer of GCH, having mechanical properties comparable to native cartilage, and a bottom layer composed of GCBB, could be used to repair large osteochondral defects in joints. Copyright © 2012 John Wiley & Sons, Ltd. PMID:22777833

Deng, Tianzheng; Lv, Jing; Pang, Jianliang; Liu, Bing; Ke, Jie

2014-07-01

217

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

Code of Federal Regulations, 2013 CFR

...cobalt-chromium-molybdenum, and a tibial resurfacing component fabricated from ultra-high molecular weight polyethylene with carbon fibers composite, and is limited to those prostheses intended for use with bone cement (§ 888.3027). (b)...

2013-04-01

218

Composite allotransplantations of knee joint, larynx, uterus, abdominal wall, face and penis.  

PubMed

One of the most important and most spectacular achievements in the field of medicine in the past 10 years are new possibilities of tissue reconstruction with help of composite tissue transplantation. As long as the upper limb transplantation can be considered as standard therapeutic procedures, the status of other composite tissue transplantations is still unclear. The aim of the work is to present a review of the actual situation in the field. PMID:18290563

Che?mo?ski, Adam; Jab?ecki, Jerzy; Sycz, Zbigniew

2007-01-01

219

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

NASA Astrophysics Data System (ADS)

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

Lin, Wen P.

220

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

SciTech Connect

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 is unacceptable for potential use in a high temperature electrochemical device. An alternative braze alloy composition designed for oxidation resistance has been developed to join ferritic stainless steel to a variety of electrochemically active ceramic membranes including YSZ, nickel oxide, and mixed conducting perovskite oxides. The results of this study to date will be discussed.

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

2003-05-15

221

Structural health monitoring of composite T-joints for assessing the integrity of damage zones  

NASA Astrophysics Data System (ADS)

This paper uses one category of Structural Health Monitoring (SHM) which uses strain variation across a structure as the key to damage detection. The structure used in this study was made from Glass Fibre Reinforced Plastic (GFRP). This paper discusses a technique developed called "Global Neural network Architecture Incorporating Sequential Processing of Internal sub Networks (GNAISPIN)" to predict the presence of multiple damage zones, determine their positions and also predict the extent of damage. Finite Element (FE) models of T-joints, used in ship structures, were created using MSC Patran(R) . These FE models were created with delaminations embedded at various locations across the bond-line of the structure. The resulting strain variation across the surface of the structure was observed. The validity of the Finite Element model was then verified experimentally. GNAISPIN was then used in tandem with the Damage Relativity Analysis Technique to predict and estimate the presence of multiple delaminations.

Kesavan, A.; Deivasigamani, M.; John, S.; Herszberg, I.

2006-04-01

222

Effect of Adherend Thickness and Mixed Mode Loading on Debond Growth in Adhesively Bonded Composite Joints  

Microsoft Academic Search

Symmetric and unsymmetric double cantilever beam (DCB) specimens were tested and analyzed to assess the effect of (1) adherend thickness and (2) a predominantly mode I mixed mode loading on cyclic debond growth and static fracture toughness. The specimens were made of unidirectional composite (T300\\/5208) adherends bonded together with EC3445 structural adhesive. The thickness was 8, 16 or 24 plies.

P. D. Mangalgiri; W. S. Johnson; R. A. Everett Jr

1987-01-01

223

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

NASA Astrophysics Data System (ADS)

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.

Harris, David Lee

224

Stresses in adhesively bonded joints: A closed form solution. [plate theory  

NASA Technical Reports Server (NTRS)

The plane strain of adhesively bonded structures which consist of two different orthotropic adherents is considered. Assuming that the thicknesses of the adherends are constant and are small in relation to the lateral dimensions of the bonded region, the adherends are treated as plates. The transverse shear effects in the adherends and the in-plane normal strain in the adhesive are taken into account. The problem is reduced to a system of differential equations for the adhesive stresses which is solved in closed form. A single lap joint and a stiffened plate under various loading conditions are considered as examples. To verify the basic trend of the solutions obtained from the plate theory a sample problem is solved by using the finite element method and by treating the adherends and the adhesive as elastic continua. The plate theory not only predicts the correct trend for the adhesive stresses but also gives rather surprisingly accurate results.

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

1980-01-01

225

Joint analysis of continental and regional background environments in the Western Mediterranean: PM1 and PM10 concentrations and composition  

NASA Astrophysics Data System (ADS)

The complete chemical composition of atmospheric particulate matter (PM1 and PM10) from a continental (Montsec, MSC, 1570 m a.s.l.) and a regional (Montseny, MSY, 720 m a.s.l.) background site in the Western Mediterranean Basin (WMB) were jointly studied for the first time for a relatively long-term series (January 2010-March 2013). Differences on average PM concentration and composition and on seasonal variation between both sites were attributed to: distance to anthropogenic sources, altitude, height evolution of the planetary boundary layer (PBL) throughout the year, variations in the air mass origin, and changes in meteorology. The diverse meteorological episodes showed different influence at regional and continental scale. When long-range transport from Central and Eastern Europe and from North Africa occurs, the continental background site is frequently more influenced, thus indicating a preferential transport at high altitude layers. Conversely, the regional background was more influenced by regional processes. In winter, anticyclonic conditions enhance the stagnation of air masses with the consequent accumulation of pollutants at regional scale in the WMB, whereas the continental background site remains in the free troposphere. Totally different conditions drive the aerosol phenomenology in summer. Weak pressure gradients and elevated insolation generate recirculation of air masses and enhances the development of the PBL, causing the aging of aerosols and incrementing pollutant concentrations over a larger area, including the continental background. This is reflected in a more similar relative composition and absolute concentrations of PM components at both regional and continental background environments in the warmer season Peculiarities of the WMB are: (a) high relevance of African dust transport and regional dust resuspension; (b) low biomass burning contribution; (c) low summer nitrate concentrations; and (d) high aerosol homogenization in summer.

Ripoll, A.; Minguillón, M. C.; Pey, J.; Pérez, N.; Querol, X.; Alastuey, A.

2014-06-01

226

A Simulated Annealing Procedure for the Joint Inversion of Spectroscopic and Compositional Data.  

NASA Astrophysics Data System (ADS)

A simulated annealing algorithm capable of inverting thermal emission spectra and compositional data acquired from a common geologic target has been developed. The inversion allows for the identification and proportion estimation of low concentration mineral endmembers. This method will be especially applicable to the 2007 Mars Mobile Geobiology Explorer equipped with an emission spectrometer for mineralogical analyses and a Laser Induced Breakdown Spectrometer for the remote acquisition of elemental information. The coupled inversion is cast as a multidimensional minimization problem where the hyperspace volume to be investigated is defined by the library endmembers at the disposal of the algorithm. This is a vector space in which exists all possible combinations of the library endmembers, with the endmember suite serving as an orthogonal set of basis vectors that span the hyperspace. The goal of the minimization is to locate the hyperspace coordinate that has the lowest associated model error value. This will correspond to the best possible model composition and mineralogy that can be generated by linearly mixing members of the endmember mineral suite. As opposed to standard unmixing routines, the simulated annealing algorithm is flexible enough to minimize any type of model error function. This allows the algorithm to interpret elemental analyses at any level of rigor, including elemental presence, relative abundances, abundance ratios, or exact mole percent. A synthetic data set was developed and systematically degraded with noise of various form and magnitude prior to being inverted with the simulated annealing algorithm as well as two purely spectral unmixing procedures. The simulated annealing procedure outperformed both of the alternate algorithms with an overall factor of two improvement in the mean sum of squares of deviations in the solution parameters. The detailed results from synthetic data inversions as well as the analysis of laboratory data will be presented.

Seelos, F. P.; Arvidson, R. E.

2001-12-01

227

Microstructure and Phase Composition of a Low-Power YAG Laser-MAG Welded Stainless Steel Joint  

NASA Astrophysics Data System (ADS)

This article presents multipass hybrid welding of austenitic stainless steel (ASS) structure by using the low-power Nd:YAG laser-metal active gas (MAG) arc hybrid welding method. The purpose of this work is to investigate and qualify the effects of multipass hybrid welding of ASS structure on the microstructure, phase composition, weld postheat influence, and weld bead (WB) precipitated phase. The results demonstrated that sound welded joints without any solidification and shrinkage defects could be obtained after welding. The top and the bottom portions of the workpieces were joined completely. At room temperature, the microstructures of different regions in WB were different and the WB microstructures were composed of columnar ?-austenite and ?-ferrite phases. The fraction of ?-ferrite decreased from 20% to 10%, and its morphology changed orderly from lath, skeleton, vermicular to reticular with an increase in the number of welding cycles. Because of the influence of postweld heat, the weld metal phase chemistry at 3 mm distance from the top of the WB surface underwent a notable modification that corresponded to an evolution of the partition coefficients toward the parent metal values. This indicated corrosion resistance of the microstructure is equivalent to that of the parent metal.

Huang, R. S.; Kang, L.; Ma, X.

2008-12-01

228

Study on the anti-wear performance of Ni-base composite coating sucker joint that contains nano-diamond and nano-polytetrafluoroethylene.  

PubMed

With the development of oilfields, the problem of eccentric wear between casing and sucker rod in rod-pumped wells operation is more and more severe. Investigations on the eccentric wear show that the abrasion of sucker rod joint is more serious than the sucker rod itself. A new method of producing the Ni-base composite coating that contains nano-diamond and nano-polytetrafluoroethylene (PTFE) on sucker joint obtained by electrodeposition is presented in this paper. The test results show that the anti-wear performance and hardness of the sucker rod improve significantly with the increase of nano-diamond. The addition of nano-PTFE particle is useful in reducing the friction factor. Field tests demonstrate that the life of the sucker rod joint is increased and the maintenance cycle of the rod-pumped well is prolonged. PMID:19441509

Wang, Wei-Zhang; Yan, Xiang-Zhen; Wang, Hai-Wen; Wang, Ming-Bo

2009-02-01

229

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

Microsoft Academic Search

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

A. Baldan

2004-01-01

230

Effect of welding speed on mechanical strength of friction welded joint of YSZ–alumina composite and 6061 aluminum alloy  

Microsoft Academic Search

Successful application of ceramics in many devices and structures requires some type of ceramic metal joining. All applications require a high-strength metal–ceramic bond. Even successful joint formation does not guarantee mechanical soundness of the joint. The inherent differences in physical properties between the ceramic and the metal make it extremely difficult to find an effective joining process that maintains the

M. B. Uday; M. N. Ahmad Fauzi; H. Zuhailawati; A. B. Ismail

2011-01-01

231

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

NASA Astrophysics Data System (ADS)

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.

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

2014-02-01

232

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

NASA Technical Reports Server (NTRS)

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.

Howell, W. E.

1974-01-01

233

Characterization of Sn7In4.1Ag0.5Cu solder in lead-free composite solder joints of LTCC\\/PWB assembly  

Microsoft Academic Search

Purpose – The purpose of this paper is to present a novel Sn7In4.1Ag0.5Cu\\/Plastic Core Solder Ball\\/Sn4Ag0.5Cu composite solder joint configuration for second-level ball grid array (BGA) interconnections of low temperature co-fired ceramic (LTCC) modules and the thermal fatigue durability of the configuration. The purpose of using the Sn7In4.1Ag0.5Cu solder was to increase the creep\\/fatigue resistance of critical regions on the

O. Nousiainen; T. Kangasvieri; R. Rautioaho; J. Vähäkangas

2008-01-01

234

AN EXPERIMENTAL STUDY ON USING CFRP COMPOSITES TO INCREASE SHEAR STRENGTH OF RC BEAM-COLUMN JOINTS  

Microsoft Academic Search

Past experiences from recent earthquakes indicate that shear failures of beam-column connections were one of the main reasons causing significant damages and collapses of RC structures subjected to earthquake loadings. Many researchers and engineers have conducted to propose an effective way to improve the joint shear strength of beam-column connections. This paper presents an experimental study to strengthen the capacity

Kihak Lee

235

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

NASA Astrophysics Data System (ADS)

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.

Vargas-Rojas, Erik; Camarena-Arellano, Diego; Hernández-Moreno, Hilario

2014-05-01

236

Computer?based problem?solving: the effects of group composition and social skills on a cognitive, joint action task  

Microsoft Academic Search

Research concerning joint action for problem?solving on computer?based tasks in schools shows an increasing awareness that social context factors must be accounted for if cognitive development is to be effective. This study focuses on boys and girls working in single?sex or mixed?sex groups, and training for social skills as context factors and how these foci affect performance at the beginning

Peter Kutnick

1997-01-01

237

Effect of the combination of electromigration and thermomigration on phase migration and partial melting in flip chip composite SnPb solder joints  

NASA Astrophysics Data System (ADS)

Composite SnPb flip chip solder joints are used to study the combined effect of electromigration and thermomgration. The study showed that electromigration have led to the redistribution of Sn-rich phase and Pb-rich phase and displaced the low melting Sn-rich phase to the downward electron current crowding region in the contact area on the chip side. A pancake-type void forms and propagates at the contact interface and is accompanied by the migration of the Sn-rich phase followed by the partial melting of the solder joint. The migration of the Sn-rich phase was unexpected, and the location of the melting was unpredicted. We propose here that the migration of Sn-rich phase in the contact area is caused by thermomigration in the lateral direction owing to the existence of a localized hot spot at the current crowding region. The melting behavior is time dependent because it requires an incubation time for void formation, void propagation, and phase migration. Finally, the partial melting at the Sn-rich region occurs due to a large Joule heating at the end of the void growth before an electrical opening takes place.

Huang, Annie T.; Tu, K. N.; Lai, Yi-Shao

2006-08-01

238

Analysis of bonded joints. [shear stress and stress-strain diagrams  

NASA Technical Reports Server (NTRS)

A refined elastic analysis of bonded joints which accounts for transverse shear deformation and transverse normal stress was developed to obtain the stresses and displacements in the adherends and in the bond. The displacements were expanded in terms of polynomials in the thicknesswise coordinate; the coefficients of these polynomials were functions of the axial coordinate. The stress distribution was obtained in terms of these coefficients by using strain-displacement and stress-strain relations. The governing differential equations were obtained by integrating the equations of equilibrium, and were solved. The boundary conditions (interface or support) were satisfied to complete the analysis. Single-lap, flush, and double-lap joints were analyzed, along with the effects of adhesive properties, plate thicknesses, material properties, and plate taper on maximum peel and shear stresses in the bond. The results obtained by using the thin-beam analysis available in the literature were compared with the results obtained by using the refined analysis. In general, thin-beam analysis yielded reasonably accurate results, but in certain cases the errors were high. Numerical investigations showed that the maximum peel and shear stresses in the bond can be reduced by (1) using a combination of flexible and stiff bonds, (2) using stiffer lap plates, and (3) tapering the plates.

Srinivas, S.

1975-01-01

239

High density polyethylene\\/graphite nano-composites for total hip joint replacements: Processing and in vitro characterization  

Microsoft Academic Search

The main objective of the present study is to investigate how the thermal, rheological, mechanical and cytotoxicity behavior of High Density Polyethylene (HDPE) can be changed by the addition of graphite nano particles (GNPs) at different contents. The HDPE\\/GNPs composites were prepared using melt blending in a co-rotating intermeshing twin screw extruder. The in vitro tests results showed that the

H. Fouad; Rabeh Elleithy

2011-01-01

240

Compound joint: A novel design principle to improve strain allowables of FRP composite stringer run-outs  

Microsoft Academic Search

A novel design principle is presented and tested, which is able to significantly improve the crack initiation loads of composite panels with stringer terminations. Taking advantage of the stable crack growth in such structures, an artificial crack is introduced which promotes synergistic load transfer of the bolts with the bond-line, drastically reducing the strain energy release rate at the run-out

V. A. Imperiale; E. Cosentino; P. M. Weaver; I. P. Bond

2010-01-01

241

Adhesively bonded lap-joints for the composite-steel shell structure of high-speed vehicles  

Microsoft Academic Search

Recently the design and manufacture of lightweight train structures have become important in order to increase speed. Composite train structures have many advantages over conventional steel or aluminum train structures because of their high specific strength, modulus and high damping capacity, which is beneficial for NVH (noise, vibration and harshness).From the structures of high-speed trains, the upper car-body is a

Jin Min Choi

1997-01-01

242

Pin-on-disc evaluation of self-reinforced composite poly(methyl methacrylate) for total joint replacements.  

PubMed

Femoral components of hip replacements are commonly anchored in the femur with bone cement or poly(methyl methacrylate) (PMMA). Wear or fracture of bone cement can lead to loosening of the femoral component, which drastically affects the success and longevity of hip replacements. Self-reinforced composite PMMA (SRC-PMMA) has been previously developed for potential use, as a precoat material for hip replacements. The composite consists of high strength fibers that have been shown to have greatly improved mechanical properties over bulk PMMA. The goal of this work was to examine SRC-PMMA for improved wear properties, as a function of processing temperature. Pin-on-disc tests were used to characterize and rank the wear rates of SRC-PMMA and PMMA. Composites made with higher processing temperatures had significantly lower wear rates than do PMMA at a significance level of p < or = 0.05. The lowest wear rate was 8.2 microg/m, at a processing temperature of 136 degrees C, compared to a wear rate for PMMA of 13.3 microg/m. At the lowest processing temperature (105 degrees C), a wear rate higher than PMMA was found, and failure was dominated by fiber delamination. In the more completely processed samples (122 degrees C < or = T < or = 150 degrees C), wear rates were equivalent to or better than PMMA, and smoother and more homogenous wear was noted in wear tracks. Fatigue cracks were prominent at higher processing temperatures or when the wear pin was riding orthogonal to fibers. Wear particles were collected and examined. Wear particle diameter and aspect ratio showed no correlation to processing temperature, but were similar to particles retrieved from human tissue samples. PMID:16544304

Peers, William J; Wright-Charlesworth, Debra D; Miskioglu, Ibrahim

2006-10-01

243

Glycosaminoglycan components in temporomandibular joint synovial fluid as markers of joint pathology  

Microsoft Academic Search

Purpose: This study investigated the correlation between temporomandibular joint (TMJ) disease and the composition of glycosaminoglycans (GAGs) components in the synovial fluid (SF).Materials and Methods: Synovial fluid (SF) was obtained from 30 TMJs of 28 female patients diagnosed as having a displaced disc with reduction (WR) (seven joints), a displaced disc without reduction (WOR) (13 joints), osteoarthritis (OA) (five joints),

Takanori Shibata; Ken-Ichiro Murakami; Eiro Kubota; Hiroshi Maeda

1998-01-01

244

On the use of quasi-dynamic modeling for composite material structures: Analysis of adhesively bonded joints with midplane asymmetry and transverse shear deformation  

Microsoft Academic Search

Adhesively bonded joints offer an attractive alternative to bolted\\/riveted approaches to joining load bearing elements because of potential weight savings and enhanced joint strength efficiency. However, modeling of these joints including substrate asymmetry, anisotropy, thickness variation, transverse shear deformation, hygrothermal growth, and complicated models for the adhesive layer can prove to be very unwieldy. This paper presents a solution methodology

Joshua Radice; Jack Vinson

2006-01-01

245

Composites  

NSDL National Science Digital Library

In this activity, learners explore how composites work by creating and testing their own composite for an imaginary company. This activity shows learners that composites are simply materials that are made up of two or more visibly distinct substances. Use this activity to talk about how composites are everywhere in our lives.

Research, Cornell C.

2003-01-01

246

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

NASA Technical Reports Server (NTRS)

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.

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

1985-01-01

247

Joint Problems  

MedlinePLUS

... ankles and toes. Other types of arthritis include gout or pseudogout. Sometimes, there is a mechanical problem ... for more information on osteoarthritis, rheumatoid arthritis and gout. How Common are Joint Problems? Osteoarthritis, which affects ...

248

Characterization and Prediction of Fracture within Solder Joints and Circuit Boards  

NASA Astrophysics Data System (ADS)

Double cantilever beam (DCB) specimens with distinct intermetallic microstructures and different geometries were fractured under different mode ratios of loading, psi, to obtain critical strain energy release rate, Jc. The strain energy release rate at crack initiation, Jci, increased with phase angle, psi, but remained unaffected by the joint geometry. However, the steady-state energy release rate, Jcs, increased with the solder layer thickness. Also, both the Jci and Jcs decreased with the thickness of the intermetallic compound layer. Next, mode I and mixed-mode fracture tests were performed on discrete (l=2 mm and l=5 mm) solder joints arranged in a linear array between two copper bars to evaluate the J = Jci (psi) failure criteria using finite element analysis. Failure loads of both the discrete joints and the joints in commercial electronic assemblies were predicted reasonably well using the J ci from the continuous DCBs. In addition, the mode-I fracture of the discrete joints was simulated with a cohesive zone model which predicted reasonably well not only the fracture loads but also the overall load-displacement behavior of the specimen. Additionally, the Jci calculated from FEA were verified estimated from measured crack opening displacements in both the continuous and discrete joints. Finally, the pad-crater fracture mode of solder joints was characterized in terms of the Jci measured at various mode ratios, psi. Specimens were prepared from lead-free chip scale package-PCB assemblies and fractured at low and high loading rates in various bending configurations to generate a range of mode ratios. The specimens tested at low loading rates all failed by pad cratering, while the ones tested at higher loading rates fractured in the brittle intermetallic layer of the solder. The J ci of pad cratering increased with the phase angle, psi, but was independent of surface finish and reflow profile. The generality of the J =Jci(psi) failure criterion to predict pad cratering fracture was then demonstrated by predicting the fracture loads of single lap-shear specimens made from the same assemblies.

Nadimpalli, Siva Prasad Varma

249

Pyrothermal treatment of welded joints  

SciTech Connect

The results of investigation of the structure and distribution of residual stresses in welded joints in pipes after heat treatment, which includes heating of the surface being treated due to combustion of plates formed from a thermite-type material of pyrotechnic composition, placed around the perimeter of the welded joint, and also an assessment of the level of residual stresses prior to and after pyrotechnic treatment demonstrated the promising nature of the proposed method. 5 refs., 5 figs.

Serikov, S.V.; Idiyatullin, R.S.; Myakushkin, S.N.; Yaufman, V.V.

1992-03-01

250

The Shear Strength and Fracture Behavior of Sn-Ag- xSb Solder Joints with Au/Ni-P/Cu UBM  

NASA Astrophysics Data System (ADS)

This study investigates the effects of Sb addition on the shear strength and fracture behavior of Sn-Ag-based solders with Au/Ni-P/Cu underbump metallization (UBM) substrates. Sn-3Ag- xSb ternary alloy solder joints were prepared by adding 0 wt.% to 10 wt.% Sb to a Sn-3.5Ag alloy and joining them with Au/Ni-P/Cu UBM substrates. The solder joints were isothermally stored at 150°C for up to 625 h to study their microstructure and interfacial reaction with the UBM. Single-lap shear tests were conducted to evaluate the mechanical properties, thermal resistance, and failure behavior. The results show that UBM effectively suppressed intermetallic compound (IMC) formation and growth during isothermal storage. The Sb addition helped to refine the Ag3Sn compounds, further improving the shear strength and thermal resistance of the solders. The fracture behavior evolved from solder mode toward the mixed mode and finally to the IMC mode with increasing added Sb and isothermal storage time. However, SnSb compounds were found in the solder with 10 wt.% Sb; they may cause mechanical degradation of the solder after long-term isothermal storage.

Lee, Hwa-Teng; Hu, Shuen-Yuan; Hong, Ting-Fu; Chen, Yin-Fa

2008-06-01

251

Joint pain  

Microsoft Academic Search

Joint pain may result from traumas or repeated microtraumas, as in sports injuries. Pain in osteoarthritis starts before any\\u000a objective finding. It has been demonstrated that in the first stages of this disease, pain is due to intraosseous venous engorgement\\u000a for the earlier thickening of the cortical bone under the articular cartilage. The mechanisms of inflammatory pain are more\\u000a complex

Massimo Zoppi; Elisabetta Beneforti

1999-01-01

252

Joint inversion of shear wave travel time residuals and geoid and depth anomalies for long-wavelength variations in upper mantle temperature and composition along the Mid-Atlantic Ridge  

NASA Technical Reports Server (NTRS)

Measurements were carried out for SS-S differential travel time residuals for nearly 500 paths crossing the northern Mid-Atlantic Ridge, assuming that the residuals are dominated by contributions from the upper mantle near the surface bounce point of the reflected phase SS. Results indicate that the SS-S travel time residuals decrease linearly with square root of age, to an age of 80-100 Ma, in general agreement with the plate cooling model. A joint inversion was formulated of travel time residuals and geoid and bathymetric anomalies for lateral variation in the upper mantle temperature and composition. The preferred inversion solutions were found to have variations in upper mantle temperature along the Mid-Atlantic Ridge of about 100 K. It was calculated that, for a constant bulk composition, such a temperature variation would produce about a 7-km variation in crustal thickness, larger than is generally observed.

Sheehan, Anne F.; Solomon, Sean C.

1991-01-01

253

Shear strengthening of beam-column joints  

Microsoft Academic Search

Shear failure of beam-column joints is identified as the principal cause of collapse of many moment-resisting frame buildings during recent earthquakes. Effective and economical rehabilitation techniques for the upgrade of the joint shear-resistance capacity in existing structures are needed. The objective of this research is to develop effective selective rehabilitation schemes for reinforced concrete beam-column joints using advanced composite materials.

Ahmed Ghobarah; A. Said

2002-01-01

254

Composite  

NASA Astrophysics Data System (ADS)

Particle distribution and hot workability of an in situ Al-TiCp composite were investigated. The composite was fabricated by an in situ casting method using the self-propagating high-temperature synthesis of an Al-Ti-C system. Hot-compression tests were carried out, and power dissipation maps were constructed using a dynamic material model. Small globular TiC particles were not themselves fractured, but the clustering and grain boundary segregation of the particles contributed to the cracking of the matrix by causing the debonding of matrix/particle interfaces and providing a crack propagation path. The efficiency of power dissipation increased with increasing temperature and strain rate, and the maximum efficiency was obtained at a temperature of 723 K (450 °C) and a strain rate of 1/s. The microstructural mechanism occurring in the maximum efficiency domain was dynamic recrystallization. The role of particles in the plastic flow and the microstructure evolution were discussed.

Kim, Su-Hyeon; Cho, Young-Hee; Lee, Jung-Moo

2014-06-01

255

Composites  

NASA Astrophysics Data System (ADS)

Ca3Co4O9 is one of the most promising p-type thermoelectric materials because of its high dimensionless figure of merit ZT. However, polycrystalline Ca3Co4O9 ceramics shows lower ZT value than that for single crystal Ca3 Co4O9 due to its higher electrical resistivity ?. Mikami et al. have reported that the addition of Ag to Ca3Co4O9 ceramics could successfully reduce ? and enhance the power factor. On the other hand, Ohtaki et al. reported that a composite structure could be highly effective to reduce ? for ZnO dually doped with Al and Ga. In this work, we tried to enhance the power factor and reduce ? by forming Ca3Co4O9/[Ca2(Co0.65Cu0.35)2O4]0.624CoO2 composite structure. As a result, the ZT value for Ca3Co4O9/[Ca2(Co0.65Cu0.35)2O4]0.624CoO2 composites reached 0.164 at 700 °C, which was 40 % higher than the value for Ca3Co4O9.

Obata, Kohei; Chonan, Yasunori; Komiyama, Takao; Abe, Kazunori; Aoyama, Takashi; Yamaguchi, Hiroyuki; Sugiyama, Shigeaki

2014-06-01

256

ACEE composite structures technology  

NASA Technical Reports Server (NTRS)

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.

Klotzsche, M. (compiler)

1984-01-01

257

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

PubMed

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

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

2014-09-01

258

Metallurgical reactions in composite 90Pb10Sn\\/lead-free solder joints and their effect on reliability of LTCC\\/PWB assembly  

Microsoft Academic Search

Use of 90Pb10Sn solder as a noncollapsible sphere material with 95.5Sn 4Ag0.5Cu and SnInAgCu lead-free solders is investigated.\\u000a Practical reflow conditions led to strong Pb dissolution into liquid solder, resulting in >20 at.% Pb content in the original\\u000a lead-free solders. The failure mechanism of the test joints is solder cracking due to thermal fatigue, but the characteristic\\u000a lifetime of 90Pb10Sn\\/SnInAgCu

O. Nousiainen; J. Putaala; T. Kangasvieri; R. Rautioaho; J. Vähäkangas

2006-01-01

259

Process robustness of single lap ultrasonic welding of thin, dissimilar materials  

Microsoft Academic Search

Fusion welding processes, such as resistance welding and laser welding, face difficulties in welding thin layers of dissimilar materials. Ultrasonic welding overcomes many of these difficulties by using high frequency vibration and pressure to input energy into the affected area to create a solid state weld. This paper presents a process robustness study of ultrasonic welding of thin metal sheets.

T. H. Kim; J. Yum; S. J. Hu; J. P. Spicer; J. A. Abell

2011-01-01

260

INVESTIGATION OF SINGLE LAP SCREW SHEAR CONNECTION IN FIRE WITH FINITE ELEMENT MODELLING  

Microsoft Academic Search

The load bearing steel deck is used in insulated metal deck roofing system for industrial buildings with low-pitched roof areas. The steel sheeting sections are connected to the underlying purlins or more commonly straight to the steel trusses by self-drilling or self- tapping screws. The behavior of sheeting connections is important in fire conditions because of the maximum compression force

W. Lu; P. Mäkeläinen; J. Outinen

261

Static strength of riveted joints in Fibre Metal Laminates  

NASA Astrophysics Data System (ADS)

The ultimate strength of riveted joints utilizing fiber metal laminates (FML), a composite of aluminum alloy and glass or aramid prepreg layers, is investigated both analytically and experimentally. A structural analysis of the static strength of the joints, the failure modes including delamination, the effects of residual stress, and the application of a computer program to the design of joints are described.

Slagter, W. J.

1994-04-01

262

End effects in scarf joints  

NASA Technical Reports Server (NTRS)

Scarf joints with small scarf angles are especially sensitive to stiffness mismatch between adherends and to adherend tip bluntness. Pre-assembly breakage of an adherend tip where it is only a few microns thick can cause significant reduction in joint strength. Mathematically, the reason for such sensitivity is that the solutions to the governing differential equation develop boundary layer character when the scarf angles are small. The boundary layers are regions with large adhesive stresses. Experimental strength data for laminated composite adherends agree with the results of this analysis.

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

1985-01-01

263

Jointness: A Selected Bibliography.  

National Technical Information Service (NTIS)

JDEIS is the Joint Doctrine, Education and Training Community Electronic Information System. It encompasses a searchable Joint Doctrine Database, a Joint Education section that includes the JPME Prospective Research Topics Database, as well as award-winni...

L. Garder

2010-01-01

264

Joint Advanced Warfighting School.  

National Technical Information Service (NTIS)

When the United States employs military power, it does so as a joint force. The cornerstone for effective joint force employment remains Service competency, but truly effective Service warfighters must think, plan and fight jointly. The key to developing ...

J. M. Davis K. C. Bowen L. W. Schonenberg

2003-01-01

265

Understanding Joint Warfighting Experiments.  

National Technical Information Service (NTIS)

In October 1998 the United States Joint Forces Command (USJFCOM) established a Joint Warfighting Experimentation program to support Joint Concept Development. Experimentation is the unique scientific method for establishing whether hypothesized concepts a...

R. A. Kass

2001-01-01

266

Arthritis: Metacarpophalangeal (MP) Joint  

MedlinePLUS

... Z Hand Anatomy Find a Hand Surgeon Arthritis - MP Joint Email to a friend * required fields From * ... drift (See Figure 2). When arthritis affects the MP joints, the condition is called MP joint arthritis. ...

267

Simulation of automotive wrist pin joint and tribological studies of tin coated Al-Si alloy, metal matrix composites and nitrogen ceramics under mixed lubrication  

Microsoft Academic Search

Development of automotive engines with high power output demands the application of high strength materials with good tribological properties. Metal matrix composites (MMC's) and some nitrogen ceramics are of interest to replace some conventional materials in the piston\\/pin\\/connecting rod design. A simulation study has been developed to explore the possibility to employ MMC's as bearing materials and ceramics as journal

Qian Wang

1993-01-01

268

Joint Research and Development of Industrial Technology, an international research collaboration for fiscal 1997. Utilization of 3D-woven C/C composite materials to machine components.  

National Technical Information Service (NTIS)

A polygonal mirror in a printer and the main shaft of a high-speed milling machine are used as models for the development of technology for applying C/C (carbon/carbon) composite materials to machine components that are required to turn at high speeds. Va...

1998-01-01

269

Spacesuit mobility joints  

NASA Technical Reports Server (NTRS)

Joints for use in interconnecting adjacent segments of an hermetically sealed spacesuit which have low torques, low leakage and a high degree of reliability are described. Each of the joints is a special purpose joint characterized by substantially constant volume and low torque characteristics. Linkages which restrain the joint from longitudinal distension and a flexible, substantially impermeable diaphragm of tubular configuration spanning the distance between pivotally supported annuli are featured. The diaphragms of selected joints include rolling convolutions for balancing the joints, while various joints include wedge-shaped sections which enhance the range of motion for the joints.

Vykukal, H. C. (inventor)

1978-01-01

270

Analysis and design of structural bonded joints  

Microsoft Academic Search

This is the first book to focus on failure prediction, damage tolerance, optimum design and stitched joining technology for composite materials. Not only is it the first book to discuss failure mechanisms and predictions of metal and composite bonded joints using both strength of materials and fracture mechanics methods, but also examined are the analysis, design and manufacturing of stitched

L. Tong; G. P. Steven

1999-01-01

271

[Vascularized joint transfer for finger joint reconstruction].  

PubMed

In a retrospective clinical study 16 vascularized joint transfers to the hand with an average follow-up of 8.2 (3 - 15) years were evaluated. The finger joint defect was caused by trauma in 12 patients, tumour in 2 patients and infection and congenital deformity in 1 patient each. There were 14 men and 2 women. The mean age range was 26 (2 - 42) years. In 6 cases a partial vascularized joint transfer was carried out, with the transplant being harvested in two cases from non-replantable finger according to the "tissue bank concept" according to Chase and in the other two cases from the PIP-joint of the second toe. In 10 patients a complete vascularized joint transfer was carried out, with the joint being harvested from the hand in 6 cases and from the 2nd toe in 4 cases. The following criteria were evaluated: active range of motion (neutral-0-method), postoperative arthritis, growth and complications. Active range of motion of the transplanted joint was for partial PIP-joint transfer Ex/Flex 0/20/65 degrees und for partial MP-joint transfer 0/20/30 degrees . After DIP-to-PIP-joint transposition active range of motion was measured Ex/Flex 0/20/60 degrees , after PIP-to-PIP transposition 0/30/60 degrees , PIP-to-MP-transposition 0/20/80 degrees and after MP-to-MP-transposition 0/20/57 degrees . The results after microvascular PIP-joint transfer from the 2nd toe for PIP-joint reconstruction were 0/25/58 degrees for PIP-joint reconstruction and 0/15/70 degrees for MP-joint reconstruction. Arthritic changes could be seen in 3 out of 4 patients with partial vascularized joint transfer. In all complete joint transfers there was no clinical and radiological evidence of arthritis even after 15 years. In the two skeletal immature patients at the time of transfer, normal growth compared to the contralateral donor site could be seen. In 8 out of 14 patients complications occurred. In 4 cases tendolysis of the extensor tendon was necessary. In 4 patients skeletal malalignment (3 x sagittal plane, 1 x rotation) was diagnosed. In one patient flexor pulley reconstruction was necessary in order to correct a bowstring deformity. Indications for vascularized joint transfer at the finger in children is set because of lack of therapy option offering normal growth potential. In adults vascularized joint transfer is indicated in case of contraindication for prosthetic joint replacement or arthrodesis. PMID:17724645

Hierner, R; Berger, A K; Shen, Z-L

2007-08-01

272

Proprioception and joint stability  

Microsoft Academic Search

In the present paper the current clinical knowledge about proprioception is given for the shoulder, knee, ankle, elbow and the radiocarpal joint. Proprioceptive capabilities are decreased after joint injuries such as ACL or meniscus tears, shoulder dislocation, ankle sprain and in joints with degenerative joint disease. Some surgical procedures seem to restore the proprioceptive abilities; others do not. Elastic knee

J. Jerosch; M. Prymka

1996-01-01

273

[Total joint arthroplasty].  

PubMed

Control of the disease activity is enabled due to the progress of drug therapy for rheumatoid arthritis. However, surgical treatments are necessary for unresponsive cases to the drug or for achieving higher QOL, and we can attain more tight control or cure by combination of drug therapy and surgical treatments. Total joint arthroplasty provides indolence, mobility, stability and is an useful joint reconstruction method. Shoulder and elbow joint work as a reach function together, and total joint arthroplasty become adaptation when extensive joint destruction or severe pain occurrs. With the usage of biologic agents joint repair is possible in small joints, but if the joint destruction progress in weight-bearing joints, repair is impossible and total joint arthroplasty can be required. PMID:23961679

Mibe, Junya; Yamamoto, Kengo

2013-07-01

274

Design and test of lightweight sandwich T-joint for naval ships  

Microsoft Academic Search

Within the EUCLID project, ‘Survivability, Durability and Performance of Naval Composite Structures’, one task is to develop improved fibre composite joints for naval ship super structures. One type of joint in such a super structure is a T-joint between sandwich panels. An existing design consists of panels joined by filler and overlaminates of the same thickness as the skin laminates.

Helmuth Toftegaard; Aage Lystrup

2005-01-01

275

Butt Joint Tool Commissioning  

SciTech Connect

ITER Central Solenoid uses butt joints for connecting the pancakes in the CS module. The principles of the butt joining of the CICC were developed by the JAPT during CSMC project. The difference between the CSMC butt joint and the CS butt joint is that the CS butt joint is an in-line joint, while the CSMC is a double joint through a hairpin jumper. The CS butt joint has to carry the hoop load. The straight length of the joint is only 320 mm, and the vacuum chamber around the joint has to have a split in the clamp shell. These requirements are challenging. Fig.1 presents a CSMC joint, and Fig.2 shows a CS butt joint. The butt joint procedure was verified and demonstrated. The tool is capable of achieving all specified parameters. The vacuum in the end was a little higher than the target, which is not critical and readily correctable. We consider, tentatively that the procedure is established. Unexpectedly, we discover significant temperature nonuniformity in the joint cross section, which is not formally a violation of the specs, but is a point of concern. All testing parameters are recorded for QA purposes. We plan to modify the butt joining tool to improve its convenience of operation and provide all features necessary for production of butt joints by qualified personnel.

Martovetsky, N N

2007-12-06

276

Pressure suit joint analyzer  

NASA Technical Reports Server (NTRS)

A measurement system for simultaneously measuring torque and angular flexure in a pressure suit joint is described. One end of a joint under test is held rigid. A torque transducer is pivotably supported on the other movable end of a joint. A potentiometer is attached to the transducer by an arm. The wiper shaft of the potentiometer is gripped by a reference arm that rotates the wiper shaft the same angle as the flexure of joint. A signal is generated by the potentiometer which is representative of the joint flexure. A compensation circuit converts the output of the transducer to a signal representative of joint torque.

Vykukal, H. C.; Webbon, B. W. (inventors)

1982-01-01

277

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

NASA Astrophysics Data System (ADS)

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.

Tong, Michael Shou-Ming

278

Jointness A Selected Bibliography.  

National Technical Information Service (NTIS)

To assist researchers in a better understanding of how the United States armed services work together, the U.S. Army War College Library presents Jointness: A Selected Bibliography. A revised and updated version of our earlier bibliographies on jointness,...

2000-01-01

279

Large displacement spherical joint  

DOEpatents

A new class of spherical joints has a very large accessible full cone angle, a property which is beneficial for a wide range of applications. Despite the large cone angles, these joints move freely without singularities.

Bieg, Lothar F. (Albuquerque, NM); Benavides, Gilbert L. (Albuquerque, NM)

2002-01-01

280

Joints and Movements.  

National Technical Information Service (NTIS)

The report contains an explanation of anatomical concepts of joints and movements necessary in biomedical and physical therapy education. Upon completion of pamphlet, reader will be able to: (1) identify movements at any joint in the human body, (2) diffe...

P. Jacoby-Lockhart H. B. Slotnick

1979-01-01

281

1970 ÖNCES? BETONARME KÖ?E KOLON-K?R?? BA?LANTILARININ KARBON L?FL? POL?MERLERLE Ç?FT EKSENL? YÜKLEMEYE KAR?I GÜÇLEND?R?LMES? BIDIRECTIONAL LOADING OF PRE1970 RC CORNER BEAM-COLUMN JOINTS BEFORE AND AFTER REHABILITATION WITH CFRP COMPOSITES  

Microsoft Academic Search

This paper presents the results of an experimental investigation examining the efficacy of carbon fiber-reinforced polymer (CFRP) composites for rehabilitating nonseismically designed reinforced concrete corner beam-column joints with moderate or severe damage. Two full-scale corner beam-column-slab specimens, identically designed using materials and detailing deficiencies typical of pre-1970 construction, were first subjected to reverse cyclic bidirectional loading, then rehabilitated via a

Lawrence F. KAHN; Abdul-Hamid ZUREICK

2007-01-01

282

The effect of controlled shot peening on fusion welded joints  

Microsoft Academic Search

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

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

2010-01-01

283

Fatigue fracture of fully saturated bonded joints  

Microsoft Academic Search

The objective of this study was to compare the fatigue crack growth characteristics of adhesively bonded joints at several temperatures in air and salt water. Motivated by current trends in automotive structures, the specimens consisted of urethane adhesive bonding composite adherends with swirled glass fibers in an isocyanurate matrix. A modified cracked lap shear configuration under four-point bending was used

Kenneth M. Liechti; G. Alexis Arzoumanidis; Soo-Jae Park

2002-01-01

284

Active rigidity joint  

NASA Astrophysics Data System (ADS)

Unimorph active rigidity joints, constructed from Shape Memory Alloy and Shape Memory Polymer and capable of bending actuation, are reported in this work. An embedded aluminum shim was added to each joint as a structural element to facilitate actuation. Joints were actuated using ohmic Tri-Phase and pulse heating processes with different results. It appeared that openloop position control could be achieved using pulse heating. Actuator improvements and future experiments are proposed.

Geeng, Franklin; Manzo, Justin; Garcia, Ephrahim

2010-03-01

285

Experimental characterization of deployable trusses and joints  

NASA Technical Reports Server (NTRS)

The structural dynamic properties of trusses are strongly affected by the characteristics of joints connecting the individual beam elements. Joints are particularly significant in that they are often the source of nonlinearities and energy dissipation. While the joints themselves may be physically simple, direct measurement is often necessary to obtain a mathematical description suitable for inclusion in a system model. Force state mapping is a flexible, practical test method for obtaining such a description, particularly when significant nonlinear effects are present. It involves measurement of the relationship, nonlinear or linear, between force transmitted through a joint and the relative displacement and velocity across it. An apparatus and procedure for force state mapping are described. Results are presented from tests of joints used in a lightweight, composite, deployable truss built by the Boeing Aerospace Company. The results from the joint tests are used to develop a model of a full 4-bay truss segment. The truss segment was statically and dynamically tested. The results of the truss tests are presented and compared with the analytical predictions from the model.

Ikegami, R.; Church, S. M.; Keinholz, D. A.; Fowler, B. L.

1987-01-01

286

Tape Joint Stiffness.  

National Technical Information Service (NTIS)

This redport evaluates the stiffness for a standard tape-joint structural connection. This stiffness is frequently necessary when modeling a structure (e.g., a shock model). In general, for a standard cylindrical tape joint, the stiffness is 1.2 times gre...

R. P. Rechard

1986-01-01

287

Behavior of jointed pipelines  

Microsoft Academic Search

Experimental data on the axial, bending and torsional behavior of ductile cast iron pipes with rubber gasket joints is presented. Analytical expressions are provided which predict the resistance mechanisms and behavior of the joints. The bending mechanism is found to be quite different from the axial and torsional mechanism. By repeating the tests in a specially designed soil box, the

Singhal

1984-01-01

288

Investigation of joint disease  

Microsoft Academic Search

The role of nuclear medicine in the diagnosis and management of the major arthropathies is critically reviewed, with particular reference to osteoarthritis, rheumatoid and similar forms of arthritis, ankylosing spondylitis, non-specific back pain, gout, the neuropathic joint, avascular necrosis, infection and the consequences of prosthetic joint insertion. Attention is drawn both to practical applications and deficiencies in current techniques and

M. V. Merrick

1992-01-01

289

Bone and joint infections  

Microsoft Academic Search

Infections involving bone and joint are a significant cause of morbidity and mortality. They can result in prolonged hospital stays, long courses of systemic antibiotics and frequently will require surgical intervention. In this review we will cover the commonest infections seen clinically. We have also chosen to divide the review into two sections; infections involving native tissue\\/joints and infections relating

Tom Darton; Robert Townsend

2010-01-01

290

Campylobacter prosthetic joint infection.  

PubMed

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

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

2014-05-01

291

Prosthetic Elbow Joint.  

National Technical Information Service (NTIS)

An artificial manually positionable elbow joint for use in an upper extremity, above-elbow, prosthetic which provides a locking feature that is easily controlled by the wearer is described. The instant elbow joint is very strong and durable to withstand t...

B. Weddendorf

1992-01-01

292

Joint warfare system (JWARS)  

Microsoft Academic Search

The Joint Warfare System (JWARS) is a campaign-level model of military operations that is currently being developed under contract by the Office of the Secretary of Defense (OSD) for use by OSD, the Joint Staff, the Services, and the War fighting Commands. The behavior of military forces can be simulated from ports of embarkation through to their activities in combat.

A. Simlote

2003-01-01

293

General joint laxity  

Microsoft Academic Search

General joint laxity is measured with the hyperextensometer, and by analyzing the values obtained in a group of European subjects norm curves are drawn up related to age and sex. The values found in various orthopedic diseases are put into these curves, and the importance of general joint laxity is discussed.

L. Dubs; N. Gschwend

1988-01-01

294

Joint Seal Materials.  

National Technical Information Service (NTIS)

Three major experimental field installations of approximately 7 types of joint sealing materials were used to compare and evaluate the products of numerous sealant manufacturers. The sealants were placed in contraction joints (3/8 in. x 2 in.) which were ...

J. G. F. Hiss J. R. Lambert W. M. McCarty

1968-01-01

295

Composite structural materials  

NASA Technical Reports Server (NTRS)

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.

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

1979-01-01

296

Superconducting cable joint resistance  

SciTech Connect

This paper reports on results of a parametric study of the 4.2 K resistance of lap joints between two 27-strand cables of multifilamentary Nb{sub 3}Sn wire. All joints were between ribbon terminations made rolling copper-encapsulated cable ends flat. Resistances as functions of current were inferred from current decay time constants of cable-in-conduit conductor loops connected by the joints. The resistances of twenty three samples were measured (range of 0.2 to 3 n{Omega}). It was found that lap joint resistance was a function of current. The influences of solder versus no solder, solder thickness, indium versus tin-lead, ribbon surface oxidation, solder flux, cable twist pitch, wire chrome plating, clamping pressure during heat treatment, ribbon aspect ratio, and joint length are reported.

Herbelot, O.; Steeves, M.M.; Hoening, M.O. (Massachusetts Inst. of Tech., Cambridge, MA (United States). Plasma Fusion Center)

1991-03-01

297

MISR JOINT_AS Data  

MISR Data and Information Joint Aerosol Product (JOINT_AS) The MISR Level 3 Products are ... campaigns at daily and monthly time scales. The Joint Aerosol product provides a monthly global statistical summary of MISR Level 2 ...

2014-03-24

298

Cover For Duct Expansion Joint  

NASA Technical Reports Server (NTRS)

Size and shape of cover reduces stress and increases strength. Cover for expansion joints on duct-work seals tightly while accommodating movement of joint. Provides ample bonding area on both members of joint.

Brown, A. R.

1988-01-01

299

Appendicular joint dislocations.  

PubMed

This study defines the incidence and epidemiology of joint dislocations and subluxations of the appendicular skeleton. All patients presenting acutely to hospital with a dislocation or subluxation of the appendicular skeleton from a defined population were included in the study. There were 974 dislocations or subluxations over one year between the 1st November 2008 and the 31st October 2009. There was an overall joint dislocation incidence of 157/10(5)/year (188/10(5)/year in males and 128/10(5)/year in females). Males demonstrated a bimodal distribution with a peak incidence of 446/10(5)/year at 15-24 years old and another of 349/10(5)/year in those over 90 years. Females demonstrate an increasing incidence from the seventh decade with a maximum incidence of 520/10(5)/year in those over 90 years. The most commonly affected joints are the glenohumeral (51.2/10(5)/year), the small joints of the hand (29.9/10(5)/year), the patellofemoral joint (21.6/10(5)/year), the prosthetic hip (19.0/10(5)/year), the ankle (11.5/10(5)/year), the acromioclavicular joint (8.9/10(5)/year) and the elbow (5.5/10(5)/year). Unlike fractures, dislocations are more common in the both the most affluent and the most socially deprived sections of the population. Joint disruptions are more common than previously estimated. PMID:23433660

Hindle, Paul; Davidson, Eleanor K; Biant, Leela C; Court-Brown, Charles M

2013-08-01

300

Pressure vessel flex joint  

NASA Technical Reports Server (NTRS)

An airtight, flexible joint is disclosed for the interfacing of two pressure vessels such as between the Space Station docking tunnel and the Space Shuttle Orbiter bulkhead adapter. The joint provides for flexibility while still retaining a structural link between the two vessels required due to the loading created by the internal/external pressure differential. The joint design provides for limiting the axial load carried across the joint to a specific value, a function returned in the Orbiter/Station tunnel interface. The flex joint comprises a floating structural segment which is permanently attached to one of the pressure vessels through the use of an inflatable seal. The geometric configuration of the joint causes the tension between the vessels created by the internal gas pressure to compress the inflatable seal. The inflation pressure of the seal is kept at a value above the internal/external pressure differential of the vessels in order to maintain a controlled distance between the floating segment and pressure vessel. The inflatable seal consists of either a hollow torus-shaped flexible bladder or two rolling convoluted diaphragm seals which may be reinforced by a system of straps or fabric anchored to the hard structures. The joint acts as a flexible link to allow both angular motion and lateral displacement while it still contains the internal pressure and holds the axial tension between the vessels.

Kahn, Jon B. (inventor)

1992-01-01

301

Compliant Joints For Robots  

NASA Technical Reports Server (NTRS)

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.

Kerley, James J., Jr.

1990-01-01

302

Joint Injection/Aspiration  

MedlinePLUS

... bursa or tendon sheath to treat bursitis and tendonitis, respectively. What benefit is derived from a joint ... conditions, such as rheumatoid arthritis, psoriatic arthritis, gout, tendonitis, bursitis and, occasionally, osteoarthritis. What usually is injected ...

303

Joint Contingency Contracting.  

National Technical Information Service (NTIS)

The purpose of this Master of Business Administration (MBA) Professional Report is to investigate and analyze the means by which Contingency Contracting Officers (CCO) can effectively operate in a Joint contingency environment and to validate the Defense ...

E. K. Johnson B. H. Paton E. W. Threat L. A. Haptonstall

2005-01-01

304

Joint Aspiration (Arthrocentesis)  

MedlinePLUS

... arthritis, or JRA), systemic lupus erythematosus (SLE), and Lyme disease. Joint aspiration is diagnostic but it also can ... Parents MORE ON THIS TOPIC Evaluate Your Child's Lyme Disease Risk Juvenile Idiopathic Arthritis Living With Lupus Bones, ...

305

Temporomandibular Joint, Open  

MedlinePLUS

... Dental Research Loan Repayment Programs NIH Loan Repayment Programs ... glide along the joint socket of the temporal bone. The condyles slide back to their original position when we close our mouths. To keep ...

306

Acromioclavicular Joint Separations.  

National Technical Information Service (NTIS)

Acromioclavicular (AC) joint separations are common injuries of the shoulder girdle, especially in the young and active population. Typically the mechanism of this injury is a direct force against the lateral aspect of the adducted shoulder, the magnitude...

F. Martetschlaeger P. J. Millett R. J. Warth T. R. Gaskill

2013-01-01

307

Heuristics for Joint Architecting.  

National Technical Information Service (NTIS)

There is no question that Department of Defense and chairman of the Joint Chiefs of Staff directives have increased the development of operational and systems architectures. The DoD Architectural Framework (DoDAF) and its associated governing publications...

A. Piepkorn G. J. Miller J. Kennedy R. Mills T. Wieser

2006-01-01

308

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 ...

309

Joint Contact Stress  

PubMed Central

A joint's normal mechanical history contributes to the maintenance of articular cartilage and underlying bone. Loading facilitates the flow of nutrients into cartilage and waste products away, and additionally provides the mechanical signals essential for normal cell and tissue maintenance. Deleteriously low or high contact stresses have been presumed to result in joint deterioration, and particular aspects of the mechanical environment may facilitate repair of damaged cartilage. For decades, investigators have explored static joint contact stresses (under some more or less arbitrary condition) as a surrogate of the relevant mechanical history. Contact stresses have been estimated in vitro in many joints and in a number of species, although only rarely in vivo. Despite a number of widely varying techniques (and spatial resolutions) to measure these contact stresses, reported ranges of static peak normal stresses are relatively similar from joint to joint across species, and in the range of 0.5 to 5.0 MPa. This suggests vertebrate diarthrodial joints have evolved to achieve similar mechanical design criteria. Available evidence also suggests some disorders of cartilage deterioration are associated with somewhat higher peak pressures ranging from 1-20 MPa, but overlapping the range of normal pressures. Some evidence and considerable logic suggests static contact stresses per se do not predict cartilage responses, but rather temporal aspects of the contact stress history. Static contact stresses may therefore not be a reasonable surrogate for biomechanical studies. Rather, temporal and spatial aspects of the loading history undoubtedly induce beneficial and deleterious biological responses. Finally, since all articular cartilage experiences similar stresses, the concept of a "weight-bearing" versus a "non-weight-bearing" joint seems flawed, and should be abandoned.

Brand, Richard A

2005-01-01

310

Prosthetic Joint Infections  

PubMed Central

Prosthetic joint infections represent a major therapeutic challenge for both healthcare providers and patients. This paper reviews the predisposing factors, pathogenesis, microbiology, diagnosis, treatment and prophylaxis of prosthetic joint infection. The most optimal management strategy should be identified based on a number of considerations including type and duration of infection, antimicrobial susceptibility of the infecting pathogen, condition of infected tissues and bone stock, patient wishes and functional status.

Aslam, Saima; Darouiche, Rabih O.

2012-01-01

311

High pressure ceramic joint  

DOEpatents

Many recuperators have components which react to corrosive gases and are used in applications where the donor fluid includes highly corrosive gases. These recuperators have suffered reduced life, increased service or maintenance, and resulted in increased cost. The present joint when used with recuperators increases the use of ceramic components which do not react to highly corrosive gases. Thus, the present joint used with the present recuperator increases the life, reduces the service and maintenance, and reduces the increased cost associated with corrosive action of components used to manufacture recuperators. The present joint is comprised of a first ceramic member, a second ceramic member, a mechanical locking device having a groove defined in one of the first ceramic member and the second ceramic member. The joint and the mechanical locking device is further comprised of a refractory material disposed in the groove and contacting the first ceramic member and the second ceramic member. The present joint mechanically provides a high strength load bearing joint having good thermal cycling characteristics, good resistance to a corrosive environment and good steady state strength at elevated temperatures.

Ward, Michael E. (Poway, CA); Harkins, Bruce D. (San Diego, CA)

1993-01-01

312

High pressure ceramic joint  

DOEpatents

Many recuperators have components which react to corrosive gases and are used in applications where the donor fluid includes highly corrosive gases. These recuperators have suffered reduced life, increased service or maintenance, and resulted in increased cost. The present joint when used with recuperators increases the use of ceramic components which do not react to highly corrosive gases. Thus, the present joint used with the present recuperator increases the life, reduces the service and maintenance, and reduces the increased cost associated with corrosive action of components used to manufacture recuperators. The present joint is comprised of a first ceramic member, a second ceramic member, a mechanical locking device having a groove defined in one of the first ceramic member and the second ceramic member. The joint and the mechanical locking device is further comprised of a refractory material disposed in the groove and contacting the first ceramic member and the second ceramic member. The present joint mechanically provides a high strength load bearing joint having good thermal cycling characteristics, good resistance to a corrosive environment and good steady state strength at elevated temperatures. 4 figures.

Ward, M.E.; Harkins, B.D.

1993-11-30

313

IJEMS: Iowa Joint Experiment in Microgravity Solidification  

NASA Technical Reports Server (NTRS)

The Iowa Joint Experiment in Microgravity Solidification (IJEMS) is a cooperative effort between Iowa State University and the University of Iowa to study the formation of metal-matrix composites in a microgravity environment. Of particular interest is the interaction between the solid/liquid interface and the particles in suspension. The experiment is scheduled to fly on STS-69, Space Shuttle Endeavor on August 3, 1995. This project is unique in its heavy student participation and cooperation between the universities involved.

Bendle, John R.; Mashl, Steven J.; Hardin, Richard A.

1995-01-01

314

Nondestructive Evaluation of Adhesively Bonded Joints  

NASA Technical Reports Server (NTRS)

The final report consists of 5 published papers in referred journals and a technical letter to the technical monitor. These papers include the following: (1) Comparison of the effects of debonds and voids in adhesive; (2) On the peak shear stresses in adhesive joints with voids; (3) Nondestructive evaluation of adhesively bonded joints by acousto-ultrasonic technique and acoustic emission; (4) Multiaxial fatigue life evaluation of tubular adhesively bonded joints; (5) Theoretical and experimental evaluation of the bond strength under peeling loads. The letter outlines the progress of the research. Also included is preliminary information on the study of nondestructive evaluation of composite materials subjected to localized heat damage. The investigators studied the effects of localized heat on unidirectional fiber glass epoxy composite panels. Specimens of the fiber glass epoxy composites were subjected to 400 C heat for varying lengths of time. The specimens were subjected to nondestructive tests. The specimens were then pulled to their failure and acoustic emission of these specimens were measured. The analysis of the data was continuing as of the writing of the letter, and includes a finite element stress analysis of the problem.

Nayeb-Hashemi, Hamid; Rossettos, J. N.

1997-01-01

315

Dissimilar metals joint evaluation  

NASA Technical Reports Server (NTRS)

Dissimilar metals tubular joints between 2219-T851 aluminum alloy and 304L stainless steel were fabricated and tested to evaluate bonding processes. Joints were fabricated by four processes: (1) inertia (friction) weldings, where the metals are spun and forced together to create the weld; (2) explosive welding, where the metals are impacted together at high velocity; (3) co-extrusion, where the metals are extruded in contact at high temperature to promote diffusion; and (4) swaging, where residual stresses in the metals after a stretching operation maintain forced contact in mutual shear areas. Fifteen joints of each type were prepared and evaluated in a 6.35 cm (2.50 in.) O.D. size, with 0.32 cm (0.13 in.) wall thickness, and 7.6 cm (3.0 in) total length. The joints were tested to evaluate their ability to withstand pressure cycle, thermal cycle, galvanic corrosion and burst tests. Leakage tests and other non-destructive test techniques were used to evaluate the behavior of the joints, and the microstructure of the bond areas was analyzed.

Wakefield, M. E.; Apodaca, L. E.

1974-01-01

316

Periprosthetic Joint Infections  

PubMed Central

Implantation of joint prostheses is becoming increasingly common, especially for the hip and knee. Infection is considered to be the most devastating of prosthesis-related complications, leading to prolonged hospitalization, repeated surgical intervention, and even definitive loss of the implant. The main risk factors to periprosthetic joint infections (PJIs) are advanced age, malnutrition, obesity, diabetes mellitus, HIV infection at an advanced stage, presence of distant infectious foci, and antecedents of arthroscopy or infection in previous arthroplasty. Joint prostheses can become infected through three different routes: direct implantation, hematogenic infection, and reactivation of latent infection. Gram-positive bacteria predominate in cases of PJI, mainly Staphylococcus aureus and Staphylococcus epidermidis. PJIs present characteristic signs that can be divided into acute and chronic manifestations. The main imaging method used in diagnosing joint prosthesis infections is X-ray. Computed tomography (CT) scan may assist in distinguishing between septic and aseptic loosening. Three-phase bone scintigraphy using technetium has high sensitivity, but low specificity. Positron emission tomography using fluorodeoxyglucose (FDG-PET) presents very divergent results in the literature. Definitive diagnosis of infection should be made by isolating the microorganism through cultures on material obtained from joint fluid puncturing, surgical wound secretions, surgical debridement procedures, or sonication fluid. Success in treating PJI depends on extensive surgical debridement and adequate and effective antibiotic therapy. Treatment in two stages using a spacer is recommended for most chronic infections in arthroplasty cases. Treatment in a single procedure is appropriate in carefully selected cases.

Lima, Ana Lucia L.; Oliveira, Priscila R.; Carvalho, Vladimir C.; Saconi, Eduardo S.; Cabrita, Henrique B.; Rodrigues, Marcelo B.

2013-01-01

317

Robotic Bladder Joint  

NASA Technical Reports Server (NTRS)

Reliable, lightweight robotic joint suitable for variety of applications, actuated hydraulically, without need for heavy mechanical cylinders or gears on joint itself. Includes two members; first member rotates about pin at end of second member. Includes cam, over which tension line stretched. Ends of tension line anchored at end of second member opposite end that holds pin. Bladder placed on each side of second member, squeezed between second member and tension line. Pressures and/or amounts of fluid in bladders controlled by use of conventional equipment like pumps, valves, and reservoirs. Bladder on one side inflated more than on other side; greater inflation on one side causes greater stretching of tension line on that side. Greater tension pulls on cam, turning first member toward that side. Angle of joint controlled by controlling differential inflation of two bladders.

Robertson, Glen A.

1995-01-01

318

Microstructural characterization of titanium to 304 stainless steel brazed joints  

SciTech Connect

The formation of intermetallic compounds in brazed joints between titanium and 304 stainless steel is of major concern, since they considerably degrade the joint properties. This research examined the vacuum brazing of commercially pure titanium to 304 stainless steel using two different silver-copper brazing filler metals. Pure copper and silver were used to prepare the brazing filler metals in these experiments. Special attention was given to the characterization of the different phases formed at the brazed joint and the effect of the intermetallic compounds on the mechanical properties of the brazed joints. Light and electron microscopy, electron probe microanalysis, microhardness, and shear testing were used to support the investigation. From the mechanical properties point of view, brazed joints using an eutectic composition filler metal (Ag-28 wt-% Cu) proved to be superior compared to the joints prepared with a filler metal of composition Ag-46 wt-% Cu. To maximize the shear strength of the joint, the brazing time must be optimized such that interfacial reactions, titanium-iron intermetallics formation are minimized.

Camargo, P.R.C.; Liu, S. (Colorado School of Mines, Golden, CO (United States). Center for Welding and Joining Research); Trevisan, R.E. (Univ. Estadual de Campinas, Saeo Paulo (Brazil). Dept. of Fabrication Engineering)

1993-12-01

319

New Joint Sealants. Criteria, Design and Materials.  

ERIC Educational Resources Information Center

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…

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

320

Joint Fires Training Guide for a Corps Joint Task Force.  

National Technical Information Service (NTIS)

A detailed analysis of responsibilities, inputs, processes, outputs, and interactions was conducted for the staff elements and cells involved in joint fires at the Corps Joint Task Force level. This research product documents that analysis. The purpose of...

J. F. Love

1998-01-01

321

Principles of Jointness.  

National Technical Information Service (NTIS)

Despite all the attention given to jointness since World War II, there is no comprehensive theory that underpins the concept in doctrine. This is unusual in light of the large body of literature on operational art. Most military practitioners find operati...

R. C. Rubel

2001-01-01

322

Periprosthetic Joint Infection  

Microsoft Academic Search

The orthopedic community has begun to witness a worrisome rise in the incidence of periprosthetic joint infections (PJIs) caused by resistant organisms. Besides other challenges associated with treating these infections, it appears that these infections may pose a higher cost compared to infections caused by sensitive organisms. Significantly higher cost of care for treatment of infections due to methicillin-resistant organisms

Javad Parvizi; Ian M. Pawasarat; Khalid A. Azzam; Ashish Joshi; Erik N. Hansen; Kevin J. Bozic

2010-01-01

323

Joints in a Cornstarch Analog  

NSDL National Science Digital Library

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.

Crider, Juliet

324

Comparison of 2 temporomandibular joint total joint prosthesis systems  

Microsoft Academic Search

Purpose: The study goal was to evaluate the comparative outcomes of patients treated with temporomandibular joint (TMJ) total joint prostheses, using either the Christensen prosthesis (TMJ Inc, Golden, CO) (CP) or the TMJ Concepts prosthesis (TMJ Concepts Inc, Camarillo, CA; formerly Techmedica Inc) (TP). Patients and Methods: Forty-five consecutive patients treated with either CP or TP total joint prostheses were

Larry M. Wolford; Douglas J. Dingwerth; Reena M. Talwar; Marcos C. Pitta

2003-01-01

325

What is Joint Interdependence Anyway.  

National Technical Information Service (NTIS)

There is much ado lately about the concept of 'joint interdependence' in future military operations. More than one four-star general has praised Operation Desert Storm's joint deconfliction; that is, the conduct of relatively independent service operation...

C. R. Paparone J. A. Crupi

2004-01-01

326

Increasing the Strength of Adhesively Bonded Joints by Tapering the Adherends  

SciTech Connect

Wind turbine blades are often fabricated with composite materials. These composite blades are frequently attached to a metallic structure with an adhesive bond. For the baseline composite-to-steel joint considered in this study, failure typically occurs when the adhesive debonds from the steel adherend. Previous efforts established that the adhesive peel stresses strongly influence the strength of these joints for both single-cycle and fatigue loading. This study focused on reducing the adhesive peel stresses present in these joints by tapering the steel adherends. Several different tapers were evaluated using finite element analysis before arriving at a final design. To confirm that the selected taper was an improvement to the existing design, the baseline joint and the modified joint were tested in both compression and tension. In these axial tests, the compressive strengths of the joints with tapered adherends were greater than those of the baseline joints for both single-cycle and low-cycle fatigue. In addition, only a minor reduction in tensile strength was observed for the joints with tapered adherends when compared to the baseline joints. Thus, the modification would be expected to enhance the overall performance of this joint.

GUESS,TOMMY R.; METZINGER,KURT E.

1999-09-09

327

Cellular Pressure-Actuated Joint  

NASA Technical Reports Server (NTRS)

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.

McGuire, John R.

2003-01-01

328

Double slotted socket spherical joint  

DOEpatents

A new class of spherical joints is disclosed. These spherical joints are capable of extremely large angular displacements (full cone angles in excess of 270.degree.), while exhibiting no singularities or dead spots in their range of motion. These joints can improve or simplify a wide range of mechanical devices.

Bieg, Lothar F. (Albuquerque, NM); Benavides, Gilbert L. (Albuquerque, NM)

2001-05-22

329

The Challenges of Joint Attention  

Microsoft Academic Search

This paper discusses the concept of joint at- tention and the dierent skills underlying its development. We argue that joint attention is much more than gaze following or simul- taneous looking because it implies a shared intentional relation to the world. The current state-of-the-art in robotic and computational models of the dierent prerequisites of joint attention is discussed in relation

Frederic Kaplan; Verena V. Hafner

2004-01-01

330

Glued joints in hardwood timber  

Microsoft Academic Search

The use of glued joints offers an option with ample aesthetic and functional possibilities in the design of wood structures. This type of joint is used since years 1970 in countries of North and Central Europe, for the design and construction of glulam (glued laminated timber) structures. This has led to diverse investigations in the experimental analysis of joints made

D Otero Chans; J. Estévez Cimadevila; E. Martín Gutiérrez

2008-01-01

331

Phase 1 Program Joint Report  

NASA Technical Reports Server (NTRS)

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.

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

1999-01-01

332

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

PubMed Central

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.

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

2013-01-01

333

Adhesively bonded lap joints from pultruded GFRP profiles. Part II: joint strength prediction  

Microsoft Academic Search

A method to predict the strength of adhesively bonded single and double lap joints from pultruded GFRP composite adherends subjected to quasi-static axial tensile loading is presented. The method is based on a quadratic through-thickness shear–tensile interaction failure criterion. The failure criterion was deduced from measured combined through-thickness tensile and shear strength values in the outer fiber-mat layer of the

Thomas Keller; Till Vallée

2005-01-01

334

Fatigue life prediction of bonded primary joints  

NASA Technical Reports Server (NTRS)

The validation of a proposed fatigue life prediction methodology was sought through the use of aluminum butt and scarf joint and graphite/epoxy butt joint specimens in a constant amplitude fatigue environment. The structural properties of the HYSOL 9313 adhesive system were obtained by mechanical test of molded heat adhesive specimens. Aluminum contoured double cantilever beam specimens were used to generate crack velocity versus stress intensity factor data. The specific objectives were: (1) to ascertain the feasibility of predicting fatigue failure of an adhesive in a primary bonded composite structure by incorporating linear elastic crack growth behavior; and (2) to ascertain if acoustic emission and/or compliance measurement techniques can be used to detect flaws.

Knauss, J. F.

1979-01-01

335

Shoulder joint tuberculosis  

PubMed Central

Summary Background: Despite the fact that joint tuberculosis is one of the most common forms of extrapulmonary tuberculosis, it is a disease entity that is very rare in Poland (less than 100 cases a year in the last 10 years). The symptoms are non-specific, and thus the disease is rarely taken into account in preliminary differential diagnosis. Case Report: A 68-year-old female patient was admitted to the Internal Diseases Clinic due to oedema and pain of the right shoulder joint. The pain has been increasing for about 8 months. Physical examination revealed increased circumference and elevated temperature of the right shoulder joint. Limb function was retained. The full range of radiological and laboratory diagnostic examinations was performed, including the biopsy of the affected tissue which revealed the presence of Mycobacterium tuberculosis in the bacterial culture. Clinical improvement was obtained after introduction of TB drugs. Conclusions: Radiological diagnostic methods (X-ray, CT scans, MRI scans) provide high precision monitoring of articular lesions. However, the decisive diagnosis requires additional laboratory tests as well as histopathological and bacteriological assays.

Ostrowska, Monika; Gietka, Jan; Nesteruk, Tomasz; Piliszek, Agnieszka; Walecki, Jerzy

2012-01-01

336

Ruscoe 983 Joint Sealant: Product Evaluation.  

National Technical Information Service (NTIS)

This report contains a product evaluation of Ruscoe's 983 joint sealant. Ruscoe 983 is an asphalt base single compound joint sealant. It contains an aluminum fortified adhesive and is designed for use on highway expansion joints, bridge joints, and random...

S. L. Tritsch T. M. Wolfe

1986-01-01

337

38 CFR 4.45 - The joints.  

Code of Federal Regulations, 2012 CFR

...The joints. As regards the joints the factors of disability...movement than normal (from flail joint, resections, nonunion of...movements smoothly. (f) Pain on movement, swelling...and ankle are considered major joints; multiple involvements of...

2012-07-01

338

38 CFR 4.45 - The joints.  

Code of Federal Regulations, 2010 CFR

...The joints. As regards the joints the factors of disability...movement than normal (from flail joint, resections, nonunion of...movements smoothly. (f) Pain on movement, swelling...and ankle are considered major joints; multiple involvements of...

2010-07-01

339

38 CFR 4.45 - The joints.  

Code of Federal Regulations, 2011 CFR

...The joints. As regards the joints the factors of disability...movement than normal (from flail joint, resections, nonunion of...movements smoothly. (f) Pain on movement, swelling...and ankle are considered major joints; multiple involvements of...

2011-07-01

340

49 CFR 213.121 - Rail joints.  

Code of Federal Regulations, 2013 CFR

...Transportation 4 2013-10-01 2013-10-01 false Rail joints. 213.121 Section 213.121 Transportation...SAFETY STANDARDS Track Structure § 213.121 Rail joints. (a) Each rail joint, insulated joint, and compromise...

2013-10-01

341

Testing of explosive welding and welded joints: joint mechanism and properties of explosive welded joints  

Microsoft Academic Search

In this study physical mechanism of explosive welding joint was analysed. The mechanism refers to wavy joint with interpass\\u000a and without one. Plastic strain, viscosity and acoustic waves were applied to explain the problem. The own model of the mechanism\\u000a of oxide removal for the direct joint and test results confirming the bonding mechanism were showed.

Bogumil Wronka

2010-01-01

342

Optimization and implementation of the smart joint actuator  

NASA Astrophysics Data System (ADS)

A new actuator system is being developed at the Cornell Laboratory of Intelligent Material Systems to address the problems of dynamic self-actuated shape change. This low profile actuator, known as the 'smart joint', is capable of maintaining rigidity in its nominal configuration, but can be actively strained to induce rotation at flexure joints. The joint is energetically efficient, only requiring power consumption during active morphing maneuvers used to move between shapes. The composite beam mechanism uses shape memory alloy (SMA) for strain actuation, with shape memory polymer (SMP) providing actively tailored rigidity due to its thermally varying properties. The first phase of the actuator development was modeling of the generic composite structure, proving analytically and computationally that the joint can produce useful work. The next phase focuses on optimization of this joint structure and usage, including ideal layering configurations and thicknesses in order to maximize various metrics specific to particular applications. Heuristic optimization using the simulated annealing algorithm is employed to best determine the structure of the joint at various scaling ratios, layering structures, and with varying external loading taken into account. The results are briefly compared to finite element models.

Manzo, Justin; Garcia, Ephrahim

2008-05-01

343

Laboratory characterization of rock joints  

SciTech Connect

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.

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

344

Soldering of mild steels: functional joints  

Microsoft Academic Search

In recent years, adhesive joints have replaced numerous soldered joints, especially in applications where electrical conductivity is not required from the members of the joint. Nevertheless, soldered joints are still used in applications ranging from electronics to high-technology components. The present work seeks to demonstrate that soldered joints, which can be considered as functional joints, have very good mechanical properties

F. Molleda; J. Mora; E. Carillo; B. G Mellor

2003-01-01

345

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

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

Phengsavanh, Phonepaseuth; Lindberg, Jan Erik

2013-11-01

346

A model for designing functionally gradient material joints  

SciTech Connect

An analytical, thin-plate layer model was developed to assist research and development engineers in the design of functionally gradient material (FGM) joints consisting of discrete steps between end elements of dissimilar materials. Such joints have long been produced by diffusion bonding using intermediates or multiple interlayers; welding, brazing or soldering using multiple transition pieces; and glass-to-glass or glass-to-metal bonding using multiple layers to produce matched seals. More recently, FGM joints produced by self-propagating high-temperature synthesis (SHS) are attracting the attention of researchers. The model calculates temperature distributions and associated thermally induced stresses, assuming elastic behavior, for any number of layers of any thickness or composition, accounting for critically important thermophysical properties in each layer as functions of temperature. It is useful for assuring that cured-in fabrication stresses from thermal expansion mismatches will not prevent quality joint production. The model`s utility is demonstrated with general design cases.

Messler, R.W. Jr.; Jou, M.; Orling, T.T. [Rensselaer Polytechnic Inst., Troy, NY (United States)

1995-05-01

347

Shear induced toughening in bonded joints: experiments and analysis  

Microsoft Academic Search

Bonded joint specimens were fabricated from composite adherends and either an epoxy or a urethane adhesive. In mixed-mode fracture experiments, the epoxy bonded specimens generally failed by subinterfacial fracture in the composite, while specimens bonded with urethane failed very close to the adhesive\\/substrate interface. For the epoxy bonded specimens, fracture toughness did not change significantly with mode-mix, but for urethane

J. G. SWADENER; K. M. LIECHTI

2002-01-01

348

Least squares estimation of joint production functions by the differential evolution method of global optimization  

Microsoft Academic Search

Most of the studies relating to estimation of joint production functions have noted two difficulties: first that allocation of inputs to different outputs is not known, and the second that a method of estimation cannot have more than one dependent variable, which necessitates construction of a composite output transformation function. This study has conducted some simulation experiments on joint estimation

Sudhanshu Mishra

2007-01-01

349

Stress analysis of V-shaped expansion joints under internal pressure  

Microsoft Academic Search

A composite shell type, V-shaped expansion joint is analysed for the membrane and bending stresses induced in circumferential as well as meridian directions under internal pressure loading. The expansion joint consists of a toroidal shell of positive curvature, a conical shell and a toroidal shell of negative curvature, framing into a circular cylindrical pipe. Bending theory of shells of revolution

D. N. Paliwal; A. P. Upadhyaya

1997-01-01

350

Analysis of adhesive bonded joints: a unified approach  

Microsoft Academic Search

This paper presents a newly developed unified approach for the analysis and design of adhesive bonded 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 is modelled

F. Mortensen; O. T. Thomsen

2002-01-01

351

Efficiency of Beam–Column Joint Strengthened by FRP Laminates  

Microsoft Academic Search

The recent earthquakes have shown that the vulnerability and the defects of the concrete joints in beam– column framed structures were the main causes for many building collapses. Such vulnerability and defects are in general the consequences of many factors. External strengthening with composite materials represents an alternative and a sound and efficient technique to improve the performances and aptitude

N. Attari; S. Amziane; M. Chemrouk

2010-01-01

352

Fluid movement and joint capsule strains due to flexion in rabbit knees  

PubMed Central

Diarthrodial joints are freely moveable joints containing synovial fluid (SF) within a connective tissue joint capsule that allows for low-friction and low-wear articulation of the cartilaginous ends of long bones. Biomechanical cues from joint articulation regulate synoviocyte and cartilage biology via joint capsule strain, in turn altering the composition of SF. Joint flexion is clinically associated with pain in knees with arthritis and effusion, with the nociception possibly originating from joint capsule strain. The hypothesis of this study was that knee fluid volume distribution and joint capsule strain are altered with passive flexion in the rabbit model. The aims were to (a) determine the volume distribution of fluid in the joint at different total volumes and with flexion of rabbit knees ex vivo, (b) correlate the volume distribution for the ex vivo model to in vivo data, and (c) determine the strains at different locations in the joint capsule with flexion. During knee flexion, ~20% of anteriorly located joint fluid moved posteriorly, correlating well with the fluid motion observed in in vivo joints. Planar joint capsule principal strains were ~100% (tension) in the proximal–distal direction and ~ ?40% (shortening) in the circumferential direction, relative to the femur axis and 30° strain state. The joint capsule strains with flexion are consistent with the mechanics of the tendons and ligaments from which the capsule tissue is derived. The movement and mixing of SF volume with flexion determine the mechanical and biological fluid environment within the knee joint. Joint fluid movement and capsular strains affect synovial cell biology and likely modulate trans-synovial transport.

McCarty, William J.; Masuda, Koichi; Sah, Robert L.

2011-01-01

353

Bladder operated robotic joint  

NASA Technical Reports Server (NTRS)

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.

Robertson, Glen A. (inventor)

1993-01-01

354

Tarsometatarsal/Lisfranc joint.  

PubMed

Accurate early diagnosis with adequate reduction and maintenance of anatomic alignment of the dislocation or fracture within the Lisfranc joint complex have been found to be the key to successful outcomes regarding this injury. Because of the anatomic variations, the thin soft tissue envelop, and the abundance of ligamentous and capsular structures in the region, repair of these injuries can be a challenge. The classification systems used to describe these injuries aid in describing the mechanism of injury or displacement type present, which may aid in determining what treatment modality can provide the best outcome. PMID:22424486

DiDomenico, Lawrence A; Cross, Davi

2012-04-01

355

Resistance welding graphite-fiber composites  

NASA Technical Reports Server (NTRS)

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.

Lamoureux, R. T.

1980-01-01

356

Metal to ceramic sealed joint  

DOEpatents

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. 11 figures.

Lasecki, J.V.; Novak, R.F.; McBride, J.R.

1991-08-27

357

Metal to ceramic sealed joint  

DOEpatents

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.

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

1991-01-01

358

Glenohumeral Joint Injections  

PubMed Central

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.

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

2013-01-01

359

Jointly Sponsored Research Program  

SciTech Connect

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.

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

2009-03-31

360

[Aging of joint].  

PubMed

Joint disease is one of the most frequent causes of reaching a state requiring care by others. Thus, it is very important to cope with osteoarthritis (OA) in order to maintain the physical independence of elderly people. Xp findings of OA in the knee, which is the most commonly affected joint, do not correlate well with pain ; hence, on the diagnosis, MRI is useful to know the pathology of subchondral bone, cartilage or meniscus. In OA cartilage, increased degradation and decreased production of major matrix components, like type II collagen and aggrecan occur, as well as chondrocyte hypertrophy or apoptosis. In the meantime, general changes in the aging process, such as the changes of autophagy or energy metabolism, have also recently been reported. Since OA treatments at present are just against symptoms, like by NSAIDS or arthroplasty, the development of new treatment methods is expected, based on the clarification of the pathology, including consideration of the relations with aging of bone and muscles, or with metabolic syndrome. PMID:23268297

Matsui, Yasumoto; Harada, Atsushi

2013-01-01

361

Rotary Joints With Electrical Connections  

NASA Technical Reports Server (NTRS)

Power and data transmitted on many channels. Two different rotary joints equipped with electrical connections between rotating and stationary parts. One joint transmits axial thrust and serves as interface between spinning and nonspinning parts of Galileo spacecraft. Other is scanning (limitedrotation) joint that aims scientific instruments from nonspinning part. Selected features of both useful to designers of robots, advanced production equipment, and remotely controlled instruments.

Osborn, F. W.

1986-01-01

362

OIG targets contractual joint ventures.  

PubMed

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

O'Hare, Patrick K

2003-09-01

363

Disorders of the sacroiliac joint.  

PubMed

Controversies have surrounded the sacroiliac joint. The sacroiliac joint (SIJ) is a considerably complex and strong joint with limited mobility, mechanically serving as a force transducer and a shock absorber. Anatomical changes are seen in the SIJ throughout an individual's lifetime. The ligamentous system associated with the SIJ serves to enhance stability and offer proprioceptive feedback in context with the rich plexus of articular receptors. Stability in the SIJ is related to form and force closure. Movement in the SIJ is 3-D about an axis outside of the joint. The functional examination of the SIJ is related to a clinical triad. PMID:17134467

Sizer, Phillip S; Phelps, Valerie; Thompsen, Kirk

2002-03-01

364

Early Developments in Joint Action  

PubMed Central

Joint action, critical to human social interaction and communication, has garnered increasing scholarly attention in many areas of inquiry, yet its development remains little explored. This paper reviews research on the growth of joint action over the first 2 years of life to show how children become progressively more able to engage deliberately, autonomously, and flexibly in joint action with adults and peers. It is suggested that a key mechanism underlying the dramatic changes in joint action over the second year of life is the ability to reflect consciously on oneself and one’s behavior and volition and correspondingly, on the behavior, goals, and intentions of others.

Brownell, Celia A.

2012-01-01

365

Manipulators Subject to Joint Limits and Joint Velocity Limits  

Microsoft Academic Search

In this paper, a recurrent neural network called the dual neural network is proposed for online redundancy resolution of kinematically redundant manipulators. Physical constraints such as joint limits and joint velocity limits, together with the drift-free criterion as a secondary task, are incorporated into the problem formulation of redundancy resolution. Compared to other recurrent neural networks, the dual neural network

Yunong Zhang; Jun Wang; Youshen Xia

366

Problems and paradigms in joint pathology.  

PubMed Central

This short review outlines aspects of joints relevant to current problems in articular, connective tissue disease and describes the pathology of rheumatoid arthritis and osteoarthrosis. The synovial joints display greatly varying degrees of anatomical specialisation. There is also heterogeneity of microscopic structure, to illustrate which the synovial components of the sacroiliac joints are considered. The chondron is regarded as a functional unit of hyaline articular cartilage but the responses of this tissue in disease are strongly influenced by its avascularity and by the need for chondrocytes to communicate with each other and with their local and systemic environments. Hyaline cartilage is capable of molecular replacement or substitution but not of repair by regeneration; it can, however, be replaced by fibrocartilage. The bearing surfaces of hyaline articular cartilage are never planar or smooth. Rheumatoid arthritis is a paradigm of connective tissue disease. It is not only a systemic disorder which may abbreviate life but, characteristically, is an aseptic form of symmetric polyarthritis. The inheritance of HLA-DR beta 1 and of female sex predispose to rheumatoid arthritis but the cause is unknown; it may be viral. Central to the disease is destruction of articular cartilage by sustained inflammation in which activated macrophages and TH cells, possibly of restricted clonality, combine to release cytokines, proteinases and the mediators of inflammation. Osteoarthrosis is a synovial joint syndrome, not a single disease. It is characterised by a loss of and change in the composition of cartilage proteoglycans leading to failure of normal responses to stress. The results include cartilage fibrillation and loss, bone exposure and a clinical syndrome of pain and disability. Rare forms of heritable chondrodysplasia lead to premature osteoarthrosis but, in most instances, the cause of osteoarthrosis appears to be either excess, inappropriate or insufficient mechanical demand, or traumatic, infective, inflammatory, endocrine or metabolic disease. There remain idiopathic ('primary') cases in which no cause is demonstrable. Images Fig. 2 Fig. 3

Gardner, D L

1994-01-01

367

Cracking of continuous composite beams with precast decks  

Microsoft Academic Search

Analytical and experimental studies were performed to suggest the design basis for longitudinal prestress of continuous composite bridges with full-depth precast decks. In case of continuous bridges with precast decks, combination of two kinds of prestress should be used to introduce the compression at the joints in negative moment regions, especially the joint area behind shear pockets. Two continuous composite

C.-S Shim; S.-P Chang

2003-01-01

368

Corynebacterium Prosthetic Joint Infection  

PubMed Central

Identification of Corynebacterium species may be challenging. Corynebacterium species are occasional causes of prosthetic joint infection (PJI), but few data are available on the subject. Based on the literature, C. amycolatum, C. aurimucosum, C. jeikeium, and C. striatum are the most common Corynebacterium species that cause PJI. We designed a rapid PCR assay to detect the most common human Corynebacterium species, with a specific focus on PJI. A polyphosphate kinase gene identified using whole-genome sequence was targeted. The assay differentiates the antibiotic-resistant species C. jeikeium and C. urealyticum from other species in a single assay. The assay was applied to a collection of human Corynebacterium isolates from multiple clinical sources, and clinically relevant species were detected. The assay was then tested on Corynebacterium isolates specifically associated with PJI; all were detected. We also describe the first case of C. simulans PJI.

Cazanave, Charles; Greenwood-Quaintance, Kerryl E.; Hanssen, Arlen D.

2012-01-01

369

Passive Ball Capture Joint  

NASA Technical Reports Server (NTRS)

A passive ball capture joint has a sleeve with a plurality of bores distributed about a circumference thereof and formed therethrough at an acute angle relative to the sleeve's longitudinal axis. A spring-loaded retainer is slidingly fitted in each bore and is biased such that, if allowed, will extend at least partially into the sleeve to retain a ball therein. A ring, rotatably mounted about the bores, has an interior wall defining a plurality of shaped races that bear against the spring-loaded retainers. A mechanized rotational force producer is coupled to the ring. The ring can be rotated from a first position (that presses the retainers into the sleeve to lock the ball in place) to a second position (that allows the retainers to springback out of the sleeve to release the ball).

Cloyd, Richard A. (Inventor); Bryan, Thomas C. (Inventor)

2003-01-01

370

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.

371

Slip joint connector  

NASA Technical Reports Server (NTRS)

A slip joint connector for joining first and second structural elements together is presented. The connector has a first body member attachable to the first structural element and a second body member attachable to the second structural element. The first body member has a male protuberance including a conical portion and the second body member has a conical receptacle for cooperatively receiving the conical portion of the protuberance. The protuberance includes a bridging portion for spacing the conical portion from the remainder of the first body member and the second body member has a well communicating with the conical receptacle for receiving the bridging portion. The conical male portion internally carries a nut while the second body member may receive a bolt through the receptacle to be threadedly received by the nut to secure the first and second body members tightly together.

Thomas, Frank P. (inventor)

1994-01-01

372

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.

2008-08-27

373

Relationship between joint effusion, joint pain, and protein levels in joint lavage fluid of patients with internal derangement and osteoarthritis of the temporomandibular joint  

Microsoft Academic Search

Purpose: The purpose of this study was to investigate the relationship between the presence of joint effusion, joint pain, and protein levels in joint lavage fluid (JL) of patients with internal derangement (ID) and osteoarthritis (OA) of the temporomandibular joint (TMJ).Patients and Methods: Thirty-eight joints in 26 patients with ID and OA of the TMJ were studied. Magnetic resonance imaging

Tetsu Takahashi; Hirokazu Nagai; Hiroshi Seki; Masayuki Fukuda

1999-01-01

374

Failure Limiting Pipe Expansion Joint.  

National Technical Information Service (NTIS)

The patent application describes a failure limiting pipe expansion joint for fluid conduits. It comprises a bellows, single or multi-ply, welded into each pipe section, a ribbed inner sleeve welded to the pipe at one end of the expansion joint; an outer s...

F. A. Flint

1974-01-01

375

Exercise and the Knee Joint.  

ERIC Educational Resources Information Center

This report by the President's Council on Physical Fitness and Sports examines the effects of various forms of physical exercise on the knee joint which, because of its vulnerability, is especially subject to injury. Discussion centers around the physical characteristics of the joint, commonly used measurements for determining knee stability,…

Clarke, H. Harrison, Ed.

1976-01-01

376

Joint Targeting Planning Training Guide.  

National Technical Information Service (NTIS)

This guide resulted from an effort to develop a new approach to assessment and diagnostic training feedback in joint training. The guide resulted from a front-end analysis of joint targeting for an air campaign planning simulation. The analysis generated ...

J. F. Love

1998-01-01

377

Contraction Joint for Concrete Linings.  

National Technical Information Service (NTIS)

The invention relates to a contraction joint for use in forming a layer of concrete, and more particularly to a contraction joint for use in monolithic method of forming concrete linings suitable for use in water conveyance systems, such as canals or rese...

R. A. Hill T. J. Gorman

1988-01-01

378

Joint attention and language evolution  

Microsoft Academic Search

This study investigates how more advanced joint attentional mechanisms, rather than only shared attention between two agents and an object, can be implemented and how they influence the results of language games played by these agents. We present computer simulations with language games showing that adding constructs that mimic the three stages of joint attention identified in children's early development

Johan Kwisthout; Paul Vogt; Pim Haselager; Ton Dijkstra

2008-01-01

379

[Metacarpophalangeal joint injuries and sequelae].  

PubMed

Injuries of the metacarpophalangeal joints of the thumb and fingers are of a bony or ligamentous nature. They can heal without subsequent problems if correctly diagnosed and treated but incorrect or absent diagnostics and therapy can result in chronic instability, dislocation, fusion as well as subsequent arthritis and functional limitations. They can lead to substantial impairment of the gripping function. Fractures with inclusion of joints and with fragments sufficiently large for refixation are as a rule treated operatively just as differences in torsion and instability. Persisting instabilities are secondarily stabilized by ligamentoplasty and arthritis of the metacarpophalangeal joint of the thumb is treated by fusion. For metacarpophalangeal joints of the fingers the main concern is preserving motion. Established salvage operations for arthritis include denervation, resection arthroplasty and systematic arthrolysis for impairment of the joint and contractures with intact joint surfaces. Even in chronic conditions, with appropriate treatment good functional results for metacarpophalangeal joints of the thumb and fingers can be achieved. This article presents the current pathophysiological principles and concepts for diagnostics and therapy of acute and chronic injuries of the metacarpophalangeal joints of fingers and thumbs. PMID:24700083

Meier, R

2014-04-01

380

UV-cured adhesives for carbon fiber composite applications  

NASA Astrophysics Data System (ADS)

Carbon fiber composite materials are increasingly used in automobile, marine, and aerospace industries due to their unique properties, including high strength, high stiffness and low weight. However, due to their brittle characteristic, these structures are prone to physical damage, such as a bird strike or impact damage. Once the structure is damaged, it is important to have fast and reliable temporary repair until the permanent repair or replacement can take place. In this dissertation, UV-based adhesives were used to provide a bonding strength for temporary repair. Adhesively bonded patch repair is an efficient and effective method for temporary repair. In this study, precured patches (hard patches) and dry fabric patches with laminating resins (soft patches) were performed. UV-based epoxy adhesives were applied to both patch repair systems. For precured patch repair, the bonding strengths were investigated under different surface treatments for bonding area and different adhesives thicknesses. The shear stresses of different UV exposure times and curing times were tested. Besides, the large patch repair was investigated as well. For soft patch repair, the hand wet lay-up was applied due to high viscosity of UV resins. A modified single lap shear testing (ASTM D5868) was applied to determine the shear stress. The large patches used fiber glass instead of carbon fiber to prove the possibility of repair with UV epoxy resin by hand wet lay-up process. The hand lay-up procedure was applied and assisted by vacuum pressure to eliminate the air bubbles and consolidate the patches. To enhance the bonding strength and effective soft patch repair, vacuum assisted resin transferring molding (VaRTM) is the better option. However, only low viscosity resins can be operated by VaRTM. Hence, new UV-based adhesives were formulated. The new UV-based adhesives included photoinitiator (PI), epoxy and different solvents. Solvents were used to compound the photoinitiator into epoxy monomer. Acetone, tetrahydrofuran (THF) and chloroform were used as well as their anhydrous solvents. The UV exposure times and curing times of new UV-based resins were tested. FT-IR, DSC and DMA were used to investigate structure, glass transition temperatures(Tg) and properties of polymer. In summary, the UV-based adhesive was applied to adhesively bonded hard patch and soft patch repair. In addition, new UV-based resins were formulated for the VaRTM process. The in-field repair can be effective and efficient by using UV adhesives.

Lu, Hsiao-Chun

381

Shock transmissibility of threaded joints  

SciTech Connect

Sandia National Laboratories (SNL) designs mechanical systems with threaded joints that must survive high shock environments. These mechanical systems include penetrators that must survive soil and rock penetration; drilling pipe strings that must survive rock-cutting, shock environments; and laydown weapons that must survive delivery impact shock. This paper summarizes an analytical study and an experimental evaluation of compressive, one-dimensional, shock transmission through a threaded joint in a split Hopkinson bar configuration. Thread geometries were scaled to simulate large diameter threaded joints with loadings parallel to the axis of the threads. Both strain and acceleration were evaluated with experimental measurements and analysis. Analytical results confirm the experimental conclusions that in this split Hopkinson bar configuration, the change in the one-dimensional shock wave by the threaded joint is localized to a length equal to a few diameters` length beyond the threaded joint.

Hansen, N.R.; Bateman, V.I.; Brown, F.A.

1996-12-31

382

Temporomandibular joint reconstruction with total alloplastic joint replacement.  

PubMed

This paper is a preliminary paper which presents the early findings of an ongoing prospective trial on the use of the TMJ Concepts and Biomet Lorenz total joint replacement systems for the reconstruction of the temporomandibular joint (TMJ). Total alloplastic replacement of the TMJ has become a viable option for many people who suffer from TMJ disease where surgical reconstruction is indicated. Degenerative joint diseases such as osteoarthritis, rheumatoid arthritis, psoriatic arthritis, TMJ ankylosis, malunited condylar fractures and tumours can be successfully treated using this technique. There are a number of TMJ prostheses available. Two of the joint replacement products, which have been found to be most reliable and have FDA approval in the United States, are the TMJ Concepts system and the Biomet Lorenz system, and for this reason they are being investigated in this study. This study presents the findings of seven patients with a total of 12 joint replacements using either the TMJ Concepts system or the Biomet Lorenz joint system. Two patients (3 joints) had the TMJ Concepts system and five patients (9 joints) had the Biomet Lorenz system. Although still early, the results were generally pleasing, with the longest replacement having been in position for three years and the most recent six months. The average postoperative mouth opening was 29.7 mm (range 25-35 mm) with an average pain score of 1.7 (range 0-3, minimum score of 0 and maximum 10). Complications were minimal and related to sensory disturbance to the lip in one patient and joint dislocation in two patients. PMID:21332746

Jones, R H B

2011-03-01

383

The failure of fibre composites and adhesively bonded fibre composites under high rates of test  

Microsoft Academic Search

The failure of fibre composites and adhesively bonded fibre composites under high rates of test, up to rates of about 15 m s-1 were studied in detail. The present paper. Part I of the series, considers the experimental aspects of the mode I fracture of the fibre composite materials and joints. Part II will analyse the dynamic effects which are

B. R. K. Blackman; J. P. Dear; A. J. Kinloch; H. MacGillivray; Y. Wang; J. G. Williams; P. Yayla

1995-01-01

384

General joint hypermobility and temporomandibular joint derangement in adolescents.  

PubMed Central

Joint mobility was assessed in each member of an epidemiological sample of 96 girls and 97 boys, 17 years old, and graded by means of the hypermobility score of Beighton et al. Twenty two per cent of the girls and 3% of the boys could perform five or more of the nine manoeuvres. The prevalence of symptoms and signs of internal derangement in the temporomandibular joint was higher in adolescents with hypermobility of joints (score greater than or equal to 5/9). In subjects with a high mobility score oral parafunctions (overuse) correlated more strongly with several signs and symptoms of craniomandibular disorder than in those with a low score.

Westling, L; Mattiasson, A

1992-01-01

385

Three groups in the 28 joints for rheumatoid arthritis synovitis--analysis using more than 17,000 assessments in the KURAMA database.  

PubMed

Rheumatoid arthritis (RA) is a joint-destructive autoimmune disease. Three composite indices evaluating the same 28 joints are commonly used for the evaluation of RA activity. However, the relationship between, and the frequency of, the joint involvements are still not fully understood. Here, we obtained and analyzed 17,311 assessments for 28 joints in 1,314 patients with RA from 2005 to 2011 from electronic clinical chart templates stored in the KURAMA (Kyoto University Rheumatoid Arthritis Management Alliance) database. Affected rates for swelling and tenderness were assessed for each of the 28 joints and compared between two different sets of RA patients. Correlations of joint symptoms were analyzed for swellings and tenderness using kappa coefficient and eigen vectors by principal component analysis. As a result, we found that joint affected rates greatly varied from joint to joint both for tenderness and swelling for the two sets. Right wrist joint is the most affected joint of the 28 joints. Tenderness and swellings are well correlated in the same joints except for the shoulder joints. Patients with RA tended to demonstrate right-dominant joint involvement and joint destruction. We also found that RA synovitis could be classified into three categories of joints in the correlation analyses: large joints with wrist joints, PIP joints, and MCP joints. Clustering analysis based on distribution of synovitis revealed that patients with RA could be classified into six subgroups. We confirmed the symmetric joint involvement in RA. Our results suggested that RA synovitis can be classified into subgroups and that several different mechanisms may underlie the pathophysiology in RA synovitis. PMID:23555018

Terao, Chikashi; Hashimoto, Motomu; Yamamoto, Keiichi; Murakami, Kosaku; Ohmura, Koichiro; Nakashima, Ran; Yamakawa, Noriyuki; Yoshifuji, Hajime; Yukawa, Naoichiro; Kawabata, Daisuke; Usui, Takashi; Yoshitomi, Hiroyuki; Furu, Moritoshi; Yamada, Ryo; Matsuda, Fumihiko; Ito, Hiromu; Fujii, Takao; Mimori, Tsuneyo

2013-01-01

386

Provocative sacroiliac joint maneuvers and sacroiliac joint block are unreliable for diagnosing sacroiliac joint pain  

Microsoft Academic Search

Mapping studies of pain elicited by injections into the sacroiliac joints (SIJs) suggest that sacroiliac joint syndrome (SIJS) may manifest as low back pain, sciatica, or trochanteric pain. Neither patient-reported symptoms nor provocative SIJ maneuvers are sensitive or specific for SIJS when SIJ block is used as the diagnostic gold standard. This has led to increasing diagnostic use of SIJ

Jean-Marie Berthelot; Jean-Jacques Labat; Benoît Le Goff; François Gouin; Yves Maugars

2006-01-01

387

22 CFR 228.34 - Joint ventures.  

Code of Federal Regulations, 2010 CFR

...Relations 1 2010-04-01 2010-04-01 false Joint ventures. 228.34 Section 228.34 Foreign Relations...Suppliers of Services for USAID Financing § 228.34 Joint ventures. A joint venture or unincorporated association...

2010-04-01

388

38 CFR 4.45 - The joints.  

Code of Federal Regulations, 2010 CFR

...extremities, the interphalangeal, metatarsal and tarsal joints of the lower extremities, the cervical vertebrae, the dorsal vertebrae, and the lumbar vertebrae, are considered groups of minor joints, ratable on a parity with major joints. The...

2009-07-01

389

Regenerative Medicine and Restoration of Joint Function.  

National Technical Information Service (NTIS)

Currently amputation, arthrodesis (joint fusion), or joint replacement are used to treat a joint with an intra-articular fracture or destroyed by a combat injury. Generation of personalized, anatomically shaped biological implants formed using techniques ...

E. Toyserkani M. Hurtig P. Zalzal R. Kandel R. Pilliar

2012-01-01

390

Metallurgy and Metallography of Braze Joints.  

National Technical Information Service (NTIS)

Metallographic examination of braze joints involves standard metallographic procedures with a need for special attention to some unique characteristics of braze joints. These unique characteristics include very thin joints and dissimilar metal combination...

M. M. McDonald

1985-01-01

391

Free Vibration Characteristics of Hybrid SPR Beams  

NASA Astrophysics Data System (ADS)

This paper deals with torsional free vibration analysis of single lap-jointed encastre hybrid SPR beams. The finite element analyses are carried out using the commercially-available ANSYS FEA program. The focus of the analysis is to reveal the influence on the natural frequencies, natural frequency ratios and mode shapes of single lap-jointed encastre hybrid SPR beams caused by variations in the material properties of the adhesives. Numerical examples show that the torsional natural frequencies of single lap jointed encastre hybrid SPR beams increase significantly as the Young's modulus of the adhesive increase, but only slight change with an increase in Poisson's ratio. The mode shapes show that there are different deformations in the jointed section of the odd and even modes. These different deformations may result different dynamic response and different stress distributions.

He, Xiaocong; Dong, Biao; Zhu, Xunzhi

2010-05-01

392

Composite drill pipe  

DOEpatents

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.

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

393

Development of cryogenic rotatable heat transfer joints  

NASA Astrophysics Data System (ADS)

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.

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

1992-07-01

394

Qualification of improved joint heaters  

NASA Technical Reports Server (NTRS)

Qualification testing of the Redesigned Solid Rocket Motor improved igniter-to-case joint and field joint heaters was conducted on the fired TEM-04 static test motor and was completed on 7 Sep. 1989. The purpose of the test was to certify the installation and performance of the improved joint heaters for use on flight motors. The changes incorporated in the improved heaters improve durability and should reduce handling damage. The igniter-to-case joint and field joint primary heater circuits were subjected to five 20-hr ON cycles. The heater redundant circuits were then subjected to one 20-hr ON cycle. Voltage, current, and temperature set point values were maintained within the specified limits for both heaters during each ON cycle. When testing was complete, both heaters were removed and inspected. No discolorations or any other anomalies were found on either of the heaters. Based on the successful completion of this test, it is recommended that the improved igniter-to-case joint and field joint heaters be used on future flight motors.

Cook, M.

1989-01-01

395

Common Bolted Joint Analysis Tool  

NASA Technical Reports Server (NTRS)

Common Bolted Joint Analysis Tool (comBAT) is an Excel/VB-based bolted joint analysis/optimization program that lays out a systematic foundation for an inexperienced or seasoned analyst to determine fastener size, material, and assembly torque for a given design. Analysts are able to perform numerous what-if scenarios within minutes to arrive at an optimal solution. The program evaluates input design parameters, performs joint assembly checks, and steps through numerous calculations to arrive at several key margins of safety for each member in a joint. It also checks for joint gapping, provides fatigue calculations, and generates joint diagrams for a visual reference. Optimum fastener size and material, as well as correct torque, can then be provided. Analysis methodology, equations, and guidelines are provided throughout the solution sequence so that this program does not become a "black box:" for the analyst. There are built-in databases that reduce the legwork required by the analyst. Each step is clearly identified and results are provided in number format, as well as color-coded spelled-out words to draw user attention. The three key features of the software are robust technical content, innovative and user friendly I/O, and a large database. The program addresses every aspect of bolted joint analysis and proves to be an instructional tool at the same time. It saves analysis time, has intelligent messaging features, and catches operator errors in real time.

Imtiaz, Kauser

2011-01-01

396

[Cartilage joint transplantation (author's transl)].  

PubMed

The present day knowledge and the practical use of cartilage joint transplantation in the knee joint are reviewed. Apart from the refixation of cartilage-bone and pure cartilage fragments, autologous transplantation has not fulfilled the expectation anticipated from animal experiments. Apart from the question of the source of the graft, the final results depends primarily on the problems of the functional adjustment of the grafted cartilage in its new position and its nutrition. Homologous cartilagenous grafting can give extraordinarily good clinical results but they are not equal to those of a truely successful graft. In spite of this, future research in cartilage joint transplantation will be concentrated on homologous grafting. PMID:919841

Morscher, E

1977-01-01

397

DOUBLE CONTRAST VISUALIZATION OF JOINTS  

PubMed Central

Double contrast arthrography, a method in which a dye and then oxygen is injected, can be used to visualize pathologic changes in the knee joint, that otherwise cannot be recognized preoperatively. In 28 cases in which the procedure was carried out there was no evidence of damage owing to it. This method is worthy of consideration for visualization of conditions in the shoulder joint, hip, or any joint having a distensible cavity. ImagesFigure A.Figure B.Figure C.Figure D.Figure E.

Parker, Leon O.; DeLorimier, Alfred A.

1953-01-01

398

Periprosthetic joint infection: Current concept  

PubMed Central

Periprosthetic joint infection (PJI) is one of the most devastating and costly complications following total joint arthroplasty (TJA). Diagnosis and management of PJI is challenging for surgeons. There is no “gold standard” for diagnosis of PJI, making distinction between septic and aseptic failures difficult. Additionally, some of the greatest difficulties and controversies involve choosing the optimal method to treat the infected joint. Currently, there is significant debate as to the ideal treatment strategy for PJI, and this has led to considerable international variation in both surgical and nonsurgical management of PJI. In this review, we will discuss diagnosis and management of PJI following TJA and highlight some recent advances in this field.

Aggarwal, Vinay K; Rasouli, Mohammad R; Parvizi, Javad

2013-01-01

399

Composite structural materials. [fiber reinforced composites for aircraft structures  

NASA Technical Reports Server (NTRS)

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.

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

1981-01-01

400

Shear deformation in Sn3.5Ag and Sn3.6Ag1.0Cu solder joints subjected to asymmetric four-point bend tests  

Microsoft Academic Search

The shear deformation behavior of two lead-free solder compositions, Sn-3.5Ag (wt.%) and Sn-3.6Ag-1.0Cu (wt.%), both on copper substrates, was studied using an asymmetric four point bend technique. Four test joints were obtained from one master specimen of each composition, and each joint was subject to progressive loading, up to the maximum shear strength of the joint. One unstressed bar from

B. A. Cook; I. E. Anderson; J. L. Harringa; R. L. Terpstra; J. C. Foley; Ö. Ünal; F. C. Laabs

2001-01-01

401

Joint Technical Architecture - Air Force.  

National Technical Information Service (NTIS)

This Air Force instruction (AFI) implements Air Force Policy Directive (AFPD) 33-1, Command, Control, Communications, and Computer (C4) Systems. It mandates the Joint Technical Architecture - Air Force (JTA-AF) and describes implementation details, roles,...

2000-01-01

402

Intelligence Education for Joint Warfighting.  

National Technical Information Service (NTIS)

In June 1998 the Joint Military Intelligence College (JMIC) opened a new era by expanding education in this area for the military, intelligence professionals, and other members of the national security community at large with the introduction of an underg...

A. D. Clift

1999-01-01

403

Joint Surveillance System Distributed Tracker.  

National Technical Information Service (NTIS)

The Joint Surveillance System Distributed Tracker (JDT) was designed by Hughes Aircraft Company for use in a laboratory environment in conjunction with Command and Control experiments in support of the air defense initiative. The tracker provides a live a...

R. Leckie T. P. Humiston

1990-01-01

404

Cluster Joint Science Operations Centre.  

National Technical Information Service (NTIS)

The role that the Cluster Joint Science Operations Center (JSOC) will play in the scientific operations of the Cluster mission is described. This includes the coordination of operations and commanding of the Cluster payload and the dissemination of scienc...

E. Dunford P. Vaughan E. Golton T. Dimbylow

1993-01-01

405

Joint state and parameter estimation  

NASA Technical Reports Server (NTRS)

Recent results are described concerning the problem of state reconstruction for a class of nonlinear distributed systems. The methods are then applied to the problem of joint state and parameter estimation. An example with the wave equation is presented.

Carmichael, N.; Quinn, M. D.

1983-01-01

406

Doctrine for Joint Civil Affairs.  

National Technical Information Service (NTIS)

This doctrine addresses the use of military civil affairs assets in planning and conducting joint CA activities across the range of military operations. Mission, policy determinants, and the relation of the government of the Country concerned to the Unite...

1995-01-01

407

Joint probabilities and quantum cognition  

NASA Astrophysics Data System (ADS)

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.

de Barros, J. Acacio

2012-12-01

408

The abnormal proximal tibiofibular joint.  

PubMed

Abnormalities of the proximal tibiofibular joint are infrequently encountered. Mostly instability occurs as a result of trauma. Four types of instability are distinguished: subluxation, anterolateral, posteromedial and superior dislocation. Four radiological methods designed to visualize abnormalities of the proximal tibiofibular joint are discussed. Special notice is given to the clinical relevance of a new method. Instability was demonstrated in 19 patients; 16 of these were treated by an operation. History, data obtained by physical examination and ways of treatment are discussed. PMID:6703874

Veth, R P; Kingma, L M; Nielsen, H K

1984-01-01

409

Structural joint damage in gout.  

PubMed

This article summarizes the structural damage that is observed in advanced gout and current understanding of the mechanisms by which this damage occurs. Interactions between monosodium urate crystals and cells within the joint are described as well as knowledge gained from imaging studies. Future research directions and potential therapeutic strategies for the prevention and treatment of joint damage in gout are also discussed. PMID:24703348

Chhana, Ashika; Dalbeth, Nicola

2014-05-01

410

[Temporomandibular joint pain: radiological diagnosis].  

PubMed

Pain in the temporomandibular joint is often the result of internal derangement, other causes are traumatic, functional or inflammatory processes. Conventional radiography is indicated in case of suspected trauma or for specialised preoperative measurements to plan the treatment of various facial dysplasias. MRI and CT should be used in the context with the results of clinical investigation and of axiography to differentiate the various functional and morphological abnormalities of this joint. PMID:11762260

Robinson, S; Peloschek, P; Schmid-Schwab, M; Piehslinger, E; Kainberger, F

2001-01-01

411

Composition and energy spectra of cosmic-ray primaries in the energy range 10 13-10 15 eV/particle observed by Japanese-Russian joint balloon experiment  

NASA Astrophysics Data System (ADS)

We report experimental results obtained by the emulsion chambers on board of the long duration balloon. We have been carrying out the trans-Siberian-continental balloon flight since 1995, and the results from 1995 to 1996 experiments are presented here. Total exposure of these two years amounts to 231.5 m 2 h at the average altitude of ˜32 km. The energy range covers 10-500 TeV for proton-primary, 3-70 TeV/n for helium-primary, and 1-5 TeV/n for Fe-group ( Z=26-28), though statistics of heavy components is not yet enough. Our preliminary data show that the spectra of the proton and the helium have nearly the same power indices ˜2.80, while those of heavier ones become gradually harder as the mass gets heavier, for instance the index is ˜2.70 for CNO-group and ˜2.55 for Fe-group. It is remarkable that a very high energy proton with multi-PeV is detected in 1995 experiment, and the estimated flux of this event coincides with a simple extrapolation from the energy spectrum with the power index 2.8 observed in the range 10-500 TeV. It indicates that there is no spectral break at around 100 TeV, in contrast to the maximum energy predicted by the current shock-wave acceleration model. This evidence requires some modification on the acceleration and/or propagation mechanism. Also we present all-particle spectrum and the average primary mass in the energy range 20-1000 TeV/particle. Our preliminary data show no drastic change in mass composition over the wide energy range, at least up to 1 PeV/particle, though the statistics is not yet enough to confirm it concretely. The flight performance and the procedure of the analysis, particularly the energy determination methods and the detection efficiency calculation are also given.

Apanasenko, A. V.; Sukhadolskaya, V. A.; Derbina, V. A.; Fujii, M.; Galkine, V. I.; Getsov, G. G.; Hareyama, M.; Ichimura, M.; Ito, S.; Kamioka, E.; Kitami, T.; Kobayashi, T.; Kolesnikov, V. D.; Kopenkin, V.; Kotunova, N. M.; Kuramata, S.; Kuriyama, Y.; Lapshin, V. I.; Managadze, A. K.; Matsutani, H.; Mikami, H.; Misnikova, N. P.; Mukhamedshin, R. A.; Namiki, M.; Nanjo, H.; Nazarov, S. N.; Nikolsky, S. I.; Ohe, T.; Ohta, S.; Osedlo, V. I.; Oshuev, D. S.; Podorozhny, D. M.; Publichenko, P. A.; Rakobolskaya, I. V.; Roganova, T. M.; Saito, M.; Sazhina, G. P.; Semba, H.; Shabanova, Yu. N.; Shibata, T.; Sugimoto, H.; Sveshnikova, L. G.; Takahashi, K.; Tsuchiya, T.; Taran, V. M.; Yajima, N.; Yamagami, T.; Yamamoto, K.; Yashin, I. V.; Zamchalova, E. A.; Zatsepin, G. T.; Zayarnaya, I. S.; Runjob Collaboration

2001-10-01

412

A Reconfigurable Robot With Lockable Cylindrical Joints  

Microsoft Academic Search

This paper presents a new conceptual design for reconfigurable robots. Unlike conventional reconfigurable robots, our design does not achieve reconfigurability by utilizing modular joints. Rather, the robot is equipped with passive joints, i.e., joints without actuator or sensor, which permit changing the Denavit-Hartenberg (DH) parameters such as the link length and twist angle. The passive joints will become controllable when

Farhad Aghili; Kourosh Parsa

2009-01-01

413

49 CFR 213.351 - Rail joints.  

Code of Federal Regulations, 2013 CFR

...Transportation 4 2013-10-01 2013-10-01 false Rail joints. 213.351 Section 213.351 Transportation...Operations at Track Classes 6 and Higher § 213.351 Rail joints. (a) Each rail joint, insulated joint, and compromise...

2013-10-01

414

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

Microsoft Academic Search

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

Jun Yan; Ming Gao; Xiaoyan Zeng

2010-01-01

415

Improved Stud Designs for Wood/Metal Joints  

NASA Technical Reports Server (NTRS)

Load-transfer capacities and resistances to fatigue increased. Series of high-strength bonded-stud designs developed for joining laminated wood to metal. Test results for bonded-stud designs demonstrated joint strengths approaching 10,000 to 12,000 psi (69 to 83 MPa) in ultimate strength and 5,000 psi (34 MPa) in high cycle fatigue strength of wood/epoxy composite achieved.

Faddoul, J. R.; Zuteck, M.; Skaper, G.

1987-01-01

416

Microstructure of neutron irradiated graphite/Cu joint  

SciTech Connect

A carbon-carbon composite brazed with OFHC copper divertor structure has been irradiated by neutrons at 673K to 10 dpa. After the irradiation, microstructures and transmutation in the substrate and in the joint interface region were investigated by TEM. Void formation, which results in a degradation of brazed material, was prominent in interfaces (between C/C and a filler metal or between copper phase and silver-copper phase) and in OFHC copper substrate. 6 refs., 5 figs.

Watanabe, H.; Yoshida, N. [Kyushu Univ., Fukuoka (Japan); Muroga, T. [National Inst. for Fusion Science, Nagoya (Japan); Akiba, M. [Japan Atomic Energy Research Inst., Ibaraki (Japan)

1996-12-31

417

Microstructure of neutron irradiated graphite\\/Cu joint  

Microsoft Academic Search

A carbon-carbon composite brazed with OFHC copper divertor structure has been irradiated by neutrons at 673K to 10 dpa. After the irradiation, microstructures and transmutation in the substrate and in the joint interface region were investigated by TEM. Void formation, which results in a degradation of brazed material, was prominent in interfaces (between C\\/C and a filler metal or between

H. Watanabe; N. Yoshida; T. Muroga; M. Akiba

1996-01-01

418

Management of acromioclavicular joint injuries.  

PubMed

Acromioclavicular joint injuries are among the most common shoulder girdle injuries in athletes and most commonly result from a direct force to the acromion with the arm in an adducted position. Acromioclavicular joint injuries often present with associated injuries to the glenohumeral joint, including an increased incidence of superior labrum anterior posterior (SLAP) tears that may warrant further evaluation and treatment. Anteroposterior stability of the acromioclavicular joint is conferred by the capsule and acromioclavicular ligaments, of which the posterior and superior ligaments are the strongest. Superior-inferior stability is maintained by the coracoclavicular (conoid and trapezoid) ligaments. Type-I or type-II acromioclavicular joint injuries have been treated with sling immobilization, early shoulder motion, and physical therapy, with favorable outcomes. Return to activity can occur when normal shoulder motion and strength are obtained and the shoulder is asymptomatic as compared with the contralateral normal extremity. The management of type-III injuries remains controversial and is individualized. While a return to the previous level of functional activity with nonsurgical treatment has been documented in a number of case series, surgical reduction and coracoclavicular ligament reconstruction has been associated with a favorable outcome and can be considered in patients who place high functional demands on their shoulders or in athletes who participate in overhead sports. Surgical management is indicated for high-grade (?type IV) acromioclavicular joint injuries to achieve anatomic reduction of the acromioclavicular joint, reconstruction of the coracoclavicular ligaments, and repair of the deltotrapezial fascia. Outcomes after surgical reconstruction of the coracoclavicular ligaments have been satisfactory with regard to achieving pain relief and return to functional activities, but further improvements in the biomechanical strength of these constructs are necessary to avoid loss of reduction and creep with cyclic loading. PMID:24382728

Li, Xinning; Ma, Richard; Bedi, Asheesh; Dines, David M; Altchek, David W; Dines, Joshua S

2014-01-01

419

Prosthetic Joint Infections in Elderly Patients  

Microsoft Academic Search

Although prosthetic joint infections (PJIs) occur in a small proportion of patients following total joint arthroplasty, they\\u000a have catastrophic consequences on morbidity and joint function and carry a high economic burden in the elderly patients.\\u000a \\u000a Clinical presentation of prosthetic joint infection is highly variable, and differentiating a painful joint arthroplasty secondary\\u000a to mechanical loosening from an indolent infection can be

Camelia E Marculescu; Elie F. Berbari; Douglas R. Osmon

420

Low temperature joining of ceramic composites  

DOEpatents

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.

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

1999-07-13

421

Low temperature joining of ceramic composites  

DOEpatents

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.

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

1999-01-12

422

Low temperature joining of ceramic composites  

DOEpatents

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.

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

423

Low temperature joining of ceramic composites  

DOEpatents

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 ceramic 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.

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

1999-07-13

424

Low temperature joining of ceramic composites  

DOEpatents

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 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 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. 3 figs.

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

1999-01-12

425

Strength evaluation of socket joints  

NASA Technical Reports Server (NTRS)

This report documents the development of a set of equations that can be used to provide a relatively simple solution for identifying the strength of socket joints and for most cases avoid the need of more lengthy analyses. The analytical approach was verified by comparison of the contact load distributions to results obtained from a finite element analysis. The contacting surfaces for the specific joint in this analysis are in the shape of frustrums of a cone and are representative of the tapered surfaces in the socket-type joints used to join segments of model support systems for wind tunnels. The results are in the form of equations that can be used to determine the contact loads and stresses in the joint from the given geometry and externally applied loads. Equations were determined to define the bending moments and stresses along the length of the joints based on strength and materials principles. The results have also been programmed for a personal computer and a copy of the program is included.

Rash, Larry C.

1994-01-01

426

Creep properties of eutectic Sn3.5Ag solder joints reinforced with mechanically incorporated Ni particles  

Microsoft Academic Search

The creep deformation behavior of eutectic Sn-3.5Ag based Ni particle rein forced composite solder joints was investigated.\\u000a The Ni particle reinforced composite solder was prepared by mechanically dispersing 15 vol.% of Ni particles into eutectic\\u000a Sn-3.5Ag solder paste. Static-loading creep tests were carried out on solder joint specimens at 25 C, 65 C, and 105 C, representing\\u000a homologous temperatures ranging

F. Guo; J. Lee; J. P. Lucas; K. N. Subramanian; T. R. Bieler

2001-01-01

427

Brazing of sheet composite materials with aluminium matrix  

NASA Astrophysics Data System (ADS)

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.

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

428

Elasto-Plastic Analysis of Tee Joints Using HOT-SMAC  

NASA Technical Reports Server (NTRS)

The Higher Order Theory - Structural/Micro Analysis Code (HOT-SMAC) software package is applied to analyze the linearly elastic and elasto-plastic response of adhesively bonded tee joints. Joints of this type are finding an increasing number of applications with the increased use of composite materials within advanced aerospace vehicles, and improved tools for the design and analysis of these joints are needed. The linearly elastic results of the code are validated vs. finite element analysis results from the literature under different loading and boundary conditions, and new results are generated to investigate the inelastic behavior of the tee joint. The comparison with the finite element results indicates that HOT-SMAC is an efficient and accurate alternative to the finite element method and has a great deal of potential as an analysis tool for a wide range of bonded joints.

Arnold, Steve M. (Technical Monitor); Bednarcyk, Brett A.; Yarrington, Phillip W.

2004-01-01

429

High-temperature non-eutectic indium-tin joints fabricated by a fluxless process  

Microsoft Academic Search

A new alternative solder joint made of a non-eutectic indium–tin (In–Sn) multilayer composite deposited in high vacuum is reported. The unique features of this design are that it is fluxless, oxidation-free, and more importantly the fabricated joint achieves a re-melting temperature significantly higher than the bonding temperature. The In–Sn non-eutectic multilayer structure with a thin gold film evaporated as a

Ricky W Chuang; Chin C Lee

2002-01-01

430

Brazed nickel\\/columbium dissimilar metal pipe joints for 720 C service  

Microsoft Academic Search

Direct brazing was investigated for fabricating Hastelloy X\\/Niobium alloy dissimilar metal pipe joints for possible use in a Brayton cycle space power system. These joints must remain leak-tight in space for up to seven years at 720°C (1328°F). Design and fabrication are complicated because of differences in composition and thermal expansion between the Ni- and Nb-base components. Two filler metals,

G. K. Watson; T. J. Moore

1977-01-01

431

Evaluation of cast-on-strap joints in lead-acid batteries  

Microsoft Academic Search

The effects of various processing parameters on the lug–strap joint quality of lead-acid auto-batteries are investigated using a laboratory scale cast-on-strap (C.O.S.) set-up. The results indicate that while good quality joints are easily obtained at low cooling rates, at high cooling rate all the C.O.S. parameters such as flux type, strap composition and melt temperature must be carefully controlled to

B. Niroumand; H. Mirzadeh; M. Reisi

2009-01-01

432

Experimental Joint Immobilization in Guinea Pigs. Effects on the Knee Joint.  

National Technical Information Service (NTIS)

In young and adult guinea pigs, the aftermath experimentally induced by the immobilization of the knee joint in hyperextended forced position was studied. Joint immobilization which varied from one to nine weeks was attained by plaster. Eighty knee joints...

J. P. Marcondesdesouza F. F. Machado A. Sesso V. Valeri

1980-01-01

433

Weapons Innovation and Joint System Development: A Case Study of the Joint STARS Program.  

National Technical Information Service (NTIS)

The Joint Surveillance Target Attack Radar System (Joint STARS) is an airborne system developed jointly by the Army and Air Force to provide real-time battlefield surveillance of stationary and moving ground targets. The developmental system made its debu...

S. W. Hill

1997-01-01

434

[Divorce and joint physical custody].  

PubMed

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

Golse, B

2014-04-01

435

Solder Joint Health Monitoring Testbed  

NASA Technical Reports Server (NTRS)

A method of monitoring the health of selected solder joints, called SJ-BIST, has been developed by Ridgetop Group Inc. under a Small Business Innovative Research (SBIR) contract. The primary goal of this research program is to test and validate this method in a flight environment using realistically seeded faults in selected solder joints. An additional objective is to gather environmental data for future development of physics-based and data-driven prognostics algorithms. A test board is being designed using a Xilinx FPGA. These boards will be tested both in flight and on the ground using a shaker table and an altitude chamber.

Delaney, Michael M.; Flynn, James G.; Browder, Mark E.

2009-01-01

436

Remission by composite scores in rheumatoid arthritis: are ankles and feet important?  

Microsoft Academic Search

Current treatment strategies aim to achieve clinical remission in order to prevent the long-term consequences of rheumatoid arthritis (RA). Several composite indices are available to assess remission. All of them include joint counts as the assessment of the major 'organ' involved in RA, but some employ reduced joint counts, such as the 28-joint count, which excludes ankles and feet. The

Theresa Kapral; Florian Dernoschnig; Klaus P Machold; Tanja Stamm; Monika Schoels; Josef S Smolen; Daniel Aletaha

2007-01-01

437

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

NASA Technical Reports Server (NTRS)

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 the finite element analyses of the splice joints are presented. The analysis results indicate that failure will not occur in the splice joint regions for loads less than the Design Ultimate Load of the wing box.

Jegley, Dawn C.

1995-01-01

438

Shear strength of beam–column joint with enlarged joint area  

Microsoft Academic Search

This paper presents planar joint enlargement for increasing the shear strength of sub-standard beam–column joint. Five beam–column specimens were tested under quasi-static cyclic loads. Two control specimens were tested. One was the beam–column joint without joint enlargement and the other was the beam–column joint strengthened by monolithically cast square enlargement. The other three specimens were strengthened by joint enlargements with

Amorn Pimanmas; Preeda Chaimahawan

2010-01-01

439

Flexible joints for thrust vector control  

NASA Technical Reports Server (NTRS)

Flexible joints have been used to achieve thrust vector control over a wide range of sizes of nozzles and have been demonstrated successfully in bench tests and static firings, and are operational on two motors. From these many joints the problems of flexible joints have been defined as establishment of the movable nozzle envelope, definition of the actuation power requirements, definition of the mechanical properties of joint materials, adhesive bonding, test methods, and quality control. These data and problem solutions are contained in a large number of reports. Data relating to joint configuration, design requirements, materials selection, joint design, structural analysis, manufacture, and testing are summarized.

Woodberry, R. F. H.

1975-01-01

440

SELECTIVE UPGRADE OF BEAM-COLUMN JOINTS WITH COMPOSITES  

Microsoft Academic Search

Many RC frames built without seismic provisions between the '50's and '70's need structural upgrade in order to match the minimum requirements of new building codes. Generally, the critical region of the strengthening design is represented by the beam-column connection. The strength hierarchy governs the upgrade requiring to protect the column and the panel so that the formation of a

A. Prota; A. Nanni; G. Manfredi; E. Cosenza

441

Active Metal Brazing of Carbon-Carbon Composites to Titanium  

NASA Technical Reports Server (NTRS)

The Ti-metal/C-C composite joints were formed by reactive brazing with three commercial brazes, namely, Cu-ABA, TiCuNi, and TiCuSil. The joint microstructures were examined using optical microscopy, and scanning electron microscopy (SEM) coupled with energy dispersive spectrometry (EDS). The results of the microstructure analysis indicate solute redistribution across the joint which led to good wetting, spreading, and metallurgical bond formation via interdiffusion.

Singh, M.; Shpargel, T. P.; Morscher, G.; Asthana, R.

2004-01-01

442

Reactive Brazing of Carbon-Carbon Composites to Titanium  

NASA Technical Reports Server (NTRS)

The Ti-metal/C-C composite joints were formed by reactive brazing with three commercial brazes, namely, Cu-ABA, TiCuNi, and TiCuSil. The joint microstructures were examined using optical microscopy, and scanning electron microscopy (SEM) coupled with energy dispersive spectrometry (EDS). The results of the microstructure analysis indicate solute redistribution across the joint and possible metallurgical bond formation via interdiffusion, which led to good wetting and spreading.

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

2004-01-01

443

Space Station Rotary Joint Mechanisms.  

National Technical Information Service (NTIS)

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 bei...

G. W. Driskill

1986-01-01

444

Space station rotary joint mechanisms  

NASA Technical Reports Server (NTRS)

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.

Driskill, Glen W.

1986-01-01

445

[Arthroscopy of the elbow joint].  

PubMed

A series of 31 patients who had elbow arthroscopy has been reviewed. Good results have been achieved after removal of loose bodies or post-traumatic hematoma. A danger of injury to periarticular structures due to the use of arthroscopic instruments, especially with pathologically decreased joint volume has been pointed out. PMID:9026412

Pawlas, R; Kio?basa, T; Chrobok, A

1996-01-01

446

Trends in biological joint resurfacing  

PubMed Central

The treatment of osteochondral lesions and osteoarthritis remains an ongoing clinical challenge in orthopaedics. This review examines the current research in the fields of cartilage regeneration, osteochondral defect treatment, and biological joint resurfacing, and reports on the results of clinical and pre-clinical studies. We also report on novel treatment strategies and discuss their potential promise or pitfalls. Current focus involves the use of a scaffold providing mechanical support with the addition of chondrocytes or mesenchymal stem cells (MSCs), or the use of cell homing to differentiate the organism’s own endogenous cell sources into cartilage. This method is usually performed with scaffolds that have been coated with a chemotactic agent or with structures that support the sustained release of growth factors or other chondroinductive agents. We also discuss unique methods and designs for cell homing and scaffold production, and improvements in biological joint resurfacing. There have been a number of exciting new studies and techniques developed that aim to repair or restore osteochondral lesions and to treat larger defects or the entire articular surface. The concept of a biological total joint replacement appears to have much potential. Cite this article: Bone Joint Res 2013;2:193–9.

Myers, K. R.; Sgaglione, N. A.; Grande, D. A.

2013-01-01

447

Preparation of soft solder joints  

Microsoft Academic Search

The preparation of solder joints in electronic applications is not easy because the solder is soft and often surrounded by hard and brittle materials. Smearing, scratching, and structural changes caused by the preparation as well as destruction of the specimens during preparation due to their filigree geometries make the procedure demanding. A sequence has been developed that enables the preparation

Günter Grossmann; Giovanni Nicoletti

1996-01-01

448

Tube Joint Leak Repair Coupling.  

National Technical Information Service (NTIS)

The coupling device consists of two split seals, one male split nut, one female split nut, and two alining pins. Each split nut is a two-piece section or two half-shell sections which are held together by a dove-tail joint and an alining pin. The male spl...

1968-01-01

449

Solders in Real Electronic Joints  

NASA Astrophysics Data System (ADS)

Undercooling and recalescence were studied using the differential scanning calorimetry (DSC) method on real electronic systems. Two solder pastes, Sn62.5Pb36.5Ag1 and Sn96.5Ag3Cu0.5, were used for preparation of electronic joints. Various combinations of these solders and soldering pads with different surface finishes such as Cu, Cu-Ni-Au, Cu-Sn, and Cu-Sn99Cu1 were used. During melting of both pastes, the Sn and Sn99Cu1 surface finishes immediately dissolved in the solder and the Cu surface coating was exposed to the melt. Therefore, practically the same undercooling was found for the Cu, Cu-Sn, and Cu-Sn99Cu1 coatings. The lowest undercooling was found for the Cu-Ni-Au surface finish for both solder pastes. If two separated electronic joints were made on the sample, two separate peaks were found in the DSC signal during solidification. In the sample with only one joint, only one exothermic peak was found. These findings were observed for all paste/surface finish combinations. These data were analyzed, showing that this effect is a consequence of undercooling and recalescence: Latent heat released during solidification of the joint increases the surrounding temperature and influences all the processes taking place.

Rudajevová, A.; Dušek, K.

2014-07-01

450

Cryopumping field joint can testing  

NASA Astrophysics Data System (ADS)

For long installations, vacuum jacketed piping often comes in 40 foot sections that are butt welded together in the field. A short can is then welded over the bare pipe connection to allow for insulation to be protected from the environment. Traditionally, the field joint is insulated with multilayer insulation and a vacuum is pulled on the can to minimize heat leak through the bare section and prevent frost from forming on the pipe section. The vacuum jacketed lines for the Ares I mobile launch platform were to be a combined 2000 feet long, with 60+ pipe sections and field joint cans. Historically, Kennedy Space Center has drilled a hole in the long sections to create a common vacuum with the field joint can to minimize maintenance on the vacuum jacketed piping. However, this effort looked at ways to use a passive system that didn't require a vacuum, but may cryopump to create its own vacuum. Various forms of aerogel, multilayer insulations, and combinations thereof were tested to determine the best method of insulating the field joint while minimizing maintenance and thermal losses.

Johnson, Wesley; Fesmire, James; Meneghelli, Barry

2012-06-01

451

Cryopumping Field Joint Can Testing  

NASA Technical Reports Server (NTRS)

For long installations, vacuum jacketed piping often comes in 40 foot sections that are butt welded together in the field. A short can is then welded over the bare pipe connection to allow for insulation to be protected from the environment. Traditionally, the field joint is insulated with multilayer insulation and a vacuum is pulled on the can to minimize heat leak through the bare section and prevent frost from forming on the pipe section. The vacuum jacketed lines for the Ares I mobile launch platform were to be a combined 2000 feet long, with 60+ pipe sections and field joint cans. Historically, Kennedy Space Center has drilled a hole in the long sections to create a common vacuum with the field joint can to minimize maintenance on the vacuum jacketed piping. However, this effort looked at ways to use a passive system that didn't require a vacuum, but may cryopump to create its own vacuum. Various forms of aerogel, multilayer insulations, and combinations thereof were tested to determine the best method of insulating the field joint while minimizing maintenance and thermal losses.

Johnson, Wesley L.; Fesmire, James E.; Meneghelli, Barry E.

2011-01-01

452

Nonoperative treatment ofacromioclavicular joint injuries  

Microsoft Academic Search

Nonoperative treatment is generally the choice for Type I and II acromioclavicular (AC) joint injuries. The situation issomewhat more controversial when Type III AC dislocations are considered, particularly with respect to athletes and heavy laborers. A number of recent studies have supported conservative treatment in these groups. There is general consensus as to the need for surgical intervention for Type

James N. Gladstone; Kevin E. Wilk; James R. Andrews

1997-01-01

453

[Arthrodesis of the talonavicular joint].  

PubMed

The talonavicular joint as part of the coxa pedis plays a pivotal role in the overall motion of the foot. The necessity for talonavicular fusion arises from isolated arthritis of posttraumatic, rheumatoid, degenerative, or idiopathic etiology. Posttraumatic arthritis is seen after malunited mid-tarsal (Chopart) fracture-dislocations and is frequently accompanied by malalignment due to an imbalance between the medial and lateral columns of the foot. In these cases a corrective arthrodesis becomes necessary. In cases of poor bone stock or arthritis of the calcaneocuboid joint, a double arthrodesis is preferred over isolated talonavicular fusion. Fusion with mini-plates is biomechanically superior to fusion with screws and especially staples, the latter being associated with non-union rates of up to 37%. Talonavicular fusion allows reproducible pain reduction in isolated arthritis with subjective patient satisfaction of between 86% and 100% in a literature review. The substantial reduction of movement in the triple joint complex leads to overload of the adjacent joints with development of arthritis in about 30% in the medium term. PMID:16193344

Rammelt, S; Marti, R K; Zwipp, H

2006-04-01

454

Automatic Locking Knee Brace Joint.  

National Technical Information Service (NTIS)

This invention is an apparatus for controlling the pivotal movement of a knee brace comprising a tang-and-clevis joint that has been uniquely modified. Both the tang and the clevis have a set of teeth that, when engaged, can lock the tang and the clevis t...

B. Weddendorf

1995-01-01

455

Interpersonal and intrapersonal coordinative modes for joint and single task performance.  

PubMed

In recent years, research in the field of social interactions has focused on the exploration of the coordinative structures that substantiate joint task performance. The current project explores whether interpersonal coordination during joint task performance gives rise to a joint coordinative structure across individuals, and whether such coordinative structures are affected by task demands. Principal component analysis (PCA) is used to identify relevant interpersonal and intrapersonal coordinative modes for the single and joint performance of a supra-postural task, which varied along its precision and role demands. In addition, cross-recurrence quantification analysis (CRQA) was combined with PCA in order to quantify the degree and stability of interpersonal coordination across intrapersonal coordinative modes. Results indicate that the composition and number of coordinative modes varied for joint compared to single performance, and that interpersonal coordination across the first coordinative mode increased in degree and stability for joint compared to single performance. Overall, these findings indicate that joint coordinative structures are affected by the nature of the task performed and the constraints it places on joint and single performance. PMID:22406503

Ramenzoni, Verónica C; Riley, Michael A; Shockley, Kevin; Baker, Aimee A

2012-10-01

456

Consequences of expansion joint bellows rupture.  

National Technical Information Service (NTIS)

Expansion joints are used in piping systems to accommodate pipe deflections during service and to facilitate fitup. Typically, the expansion joint bellows is the thinnest part of the pressure boundary, bellows rupture frequencies are typically several ord...

W. L. Daugherty R. F. Miller D. S. Cramer

1992-01-01

457

14 CFR 23.693 - Joints.  

Code of Federal Regulations, 2010 CFR

...COMMUTER CATEGORY AIRPLANES Design and Construction Control Systems § 23.693 Joints. Control system joints (in push-pull systems) that are subject to angular motion, except those in ball and roller bearing systems, must have a special...

2010-01-01

458

14 CFR 25.693 - Joints.  

Code of Federal Regulations, 2010 CFR

...TRANSPORT CATEGORY AIRPLANES Design and Construction Control Systems § 25.693 Joints. Control system joints (in push-pull systems) that are subject to angular motion, except those in ball and roller bearing systems, must have a...

2010-01-01

459

26 - LMFBR Flexible Pipe Joint Development.  

National Technical Information Service (NTIS)

Objective is the qualification of a PLBR-size primary loop flexible piping joint to the ASME Band PVC rules. Progress and activities are reported for: Class 1 flexible joint code approval support, engineering and design, material development, component te...

R. V. Anderson

1978-01-01

460

Decompression Sickness Affecting the Temporomandibular Joint.  

National Technical Information Service (NTIS)

Three cases of pain-only decompression sickness of the temporomandibular joint following altitude chamber exposure are presented. A detailed interview of each individual revealed no other joint involvement or other complaints. A careful neurologic examina...

F. W. Rudge

1990-01-01

461

Vibration Spectroscopy for Rigid Pavement Joint Assessment.  

National Technical Information Service (NTIS)

The study was conducted on the behavior of joints in concrete pavements, and on developing a non-destructive testing technique based on the frequency response of dynamically loaded joints. One of the objectives was to investigate the relationship between ...

L. Palmieri T. Krauthammer

1990-01-01

462

Bones, Muscles, and Joints: The Musculoskeletal System  

MedlinePLUS

... for example, allows for backward, forward, sideways, and rotating movement. Joints are classified by their range of ... the knees and elbows. Pivot joints allow a rotating or twisting motion, like that of the head ...

463

Arthrocentesis: the latest on joint pain relief.  

PubMed

Arthrocentesis is a procedure in the diagnostic workup and treatment of joint pain that has few complications. Analysis of joint fluid yields important treatment data. Corticosteroid and local anesthetic injections provide longer pain relief. PMID:23958670

Voll, Sandra K; Walsh, Joseph

2013-09-10

464

Side Clamped Beam (SCB) hinge system for delamination tests in beam-type composite specimens  

Microsoft Academic Search

The experimental study of composite delaminations and adhesive joints is usually carried out using beam-type specimens with bonded metallic fixtures to transfer the applied load. However, bonded joints between the composite specimen and the metallic parts might fail, especially under extreme temperature or fatigue test conditions. Moreover, the quality and alignment of the bonding procedure highly depends on the operator

J. Renart; N. Blanco; E. Pajares; J. Costa; S. Lazcano; G. Santacruz

2011-01-01

465

Seismic response of rock joints and jointed rock mass  

SciTech Connect

Long-term stability of emplacement drifts and potential near-field fluid flow resulting from coupled effects are among the concerns for safe disposal of high-level nuclear waste (HLW). A number of factors can induce drift instability or change the near-field flow patterns. Repetitive seismic loads from earthquakes and thermal loads generated by the decay of emplaced waste are two significant factors. One of two key technical uncertainties (KTU) that can potentially pose a high risk of noncompliance with the performance objectives of 10 CFR Part 60 is the prediction of thermal-mechanical (including repetitive seismic load) effects on stability of emplacement drifts and the engineered barrier system. The second KTU of concern is the prediction of thermal-mechanical-hydrological (including repetitive seismic load) effects on the host rock surrounding the engineered barrier system. The Rock Mechanics research project being conducted at the Center for Nuclear Waste Regulatory Analyses (CNWRA) is intended to address certain specific technical issues associated with these two KTUs. This research project has two major components: (i) seismic response of rock joints and a jointed rock mass and (ii) coupled thermal-mechanical-hydrological (TMH) response of a jointed rock mass surrounding the engineered barrier system (EBS). This final report summarizes the research activities concerned with the repetitive seismic load aspect of both these KTUs.

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

1996-06-01

466

Retort braze bonding of borsic/aluminum composite sheet to titanium  

NASA Technical Reports Server (NTRS)

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.

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

1975-01-01

467

Improvement of adhesive-bonded structural joints  

NASA Technical Reports Server (NTRS)

Investigation is described of methods for obtaining uniform shear stress distribution in adhesives used in double-lap bonded joints. Design rules for reducing adhesive peak shear stresses are listed. Test results of an analysis of straight-lap joint design and stepped-lap joint design are given.

Evensen, H. A.

1970-01-01

468

77 FR 39560 - International Joint Commission  

Federal Register 2010, 2011, 2012, 2013

...International Joint Commission International Joint Commission Invites...Upper Great Lakes Report The International Joint Commission (IJC...on the final report of its International Upper Great Lakes Study Board...Room A223, 1457 London Rd. MI, 7:00 pm EDT,...

2012-07-03