Analysis of Layer Waviness in Flat Compression-Loaded Thermoplastic Composite Laminates

1996 ◽  
Vol 118 (1) ◽  
pp. 63-70 ◽  
Author(s):  
Daniel O’Hare Adams ◽  
Michael W. Hyer
Keyword(s):  
Shear Stress ◽  
Compression Strength ◽  
Composite Laminates ◽  
Strength Reduction ◽  
Material Nonlinearity ◽  
Material Behavior ◽  
Thermoplastic Composite ◽  
Stress Strain ◽  
Strain Behavior ◽  
Tension And Compression

A finite element analysis was used to investigate layer waviness effects in flat compression-loaded composite laminates. Stress distributions in the vicinity of the layer waves as well as the locations and modes of failure were investigated. Two layer wave geometries were considered, each modeled within an otherwise wave-free thermoplastic composite laminate. These two wave geometries, classified as moderate and severe, corresponded to layer waves fabricated in actual laminates and tested under uniaxial compression loading. Material nonlinearities obtained from intralaminar shear and 0 and 90 deg tension and compression testing were incorporated into the analysis. The nonlinearity observed in the intralaminar shear stress-strain behavior was assumed to be valid for interlaminar shear stress-strain behavior, and the nonlinearity observed in the 90 deg tension and compression stress-strain behavior was assumed to be valid for interlaminar normal stress-strain behavior. Failure was predicted using a maximum stress failure theory. An interlaminar tension failure was predicted for the severe layer wave geometry, producing a large compression strength reduction in comparison to the wave-free laminate. Fiber compression failure was predicted for the moderate layer wave, producing only a slight compression strength reduction. Although significant material nonlinearity was present in the interlaminar compression and shear response of the material, the inclusion of material nonlinearity produced only slight decreases in predicted compression strengths relative to predictions based on linear material behavior.

Hyperelastic Muscle Simulation

2007 ◽  
Vol 345-346 ◽  
pp. 1241-1244 ◽  
Author(s):  
Mohd. Zahid Ansari ◽  
Sang Kyo Lee ◽  
Chong Du Cho
Keyword(s):  
Skeletal Muscle ◽  
Silicone Rubber ◽  
Soft Tissues ◽  
Material Model ◽  
Incompressible Material ◽  
Material Behavior ◽  
Rubber Tube ◽  
Stress Strain ◽  
Element Analysis ◽  
Strain Behavior

Biological soft tissues like muscles and cartilages are anisotropic, inhomogeneous, and nearly incompressible. The incompressible material behavior may lead to some difficulties in numerical simulation, such as volumetric locking and solution divergence. Mixed u-P formulations can be used to overcome incompressible material problems. The hyperelastic materials can be used to describe the biological skeletal muscle behavior. In this study, experiments are conducted to obtain the stress-strain behavior of a solid silicone rubber tube. It is used to emulate the skeletal muscle tensile behavior. The stress-strain behavior of silicone is compared with that of muscles. A commercial finite element analysis package ABAQUS is used to simulate the stress-strain behavior of silicone rubber. Results show that mixed u-P formulations with hyperelastic material model can be used to successfully simulate the muscle material behavior. Such an analysis can be used to simulate and analyze other soft tissues that show similar behavior.

Shear Stress–Strain Behavior of Ni-rich and Ti-rich Shape Memory Alloys at High Strain Rates

2014 ◽  
Vol 6 (9) ◽  
pp. 2024-2026 ◽  
Author(s):  
Sung Young ◽  
Jeoung-Han Kim ◽  
Yeon-Wook Kim ◽  
Dong-Teak Chung ◽  
Tae-Hyun Nam
Keyword(s):  
Shear Stress ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
High Strain ◽  
Strain Rates ◽  
High Strain Rates ◽  
Stress Strain ◽  
Strain Behavior

612 Effects of Strain Rates on Stress-Strain Behavior of Adhesive Layer under Pure Shear Stress Conditions

2000 ◽  
Vol 2000.8 (0) ◽  
pp. 203-204
Author(s):  
Akinori FUJINAMI ◽  
Katsuhiko OSAKA ◽  
Takao WADA ◽  
Takehito FUKUDA ◽  
Makoto IMANAKA
Keyword(s):  
Shear Stress ◽  
Pure Shear ◽  
Adhesive Layer ◽  
Stress Conditions ◽  
Strain Rates ◽  
Stress Strain ◽  
Strain Behavior

Extension of a Material Model for Pipeline Steels

2012 ◽  
Author(s):  
James D. Hart ◽  
Nasir Zulfiqar ◽  
Joe Zhou ◽  
Keith Adams
Keyword(s):  
Pipe Steel ◽  
Material Behavior ◽  
Matched Pair ◽  
Pipe Material ◽  
Stress Space ◽  
Stress Strain ◽  
Fitting Procedure ◽  
Yield Functions ◽  
Tension And Compression ◽  
Longitudinal Tension

Pipeline steel stress-strain curves obtained from tension and compression testing of longitudinally and circumferentially oriented specimens of the pipe wall can be significantly different e.g., the pipe material is anisotropic. The anisotropic behavior can result from the manufacturing process (e.g., due to cold expansion of UOE pipe) and can also be influenced by strain aging effects (e.g., due to heated application of pipe coating materials). As described in previous work, the Mroz multilinear kinematic hardening plasticity theory has the ability to accurately model different types of anisotropic pipe material behavior including relatively “sharp” uniaxial circumferential tension response and relatively well-rounded uniaxial longitudinal tension and compression response. The stress-strain curve fitting is accomplished by essentially selecting the sizes and initial positions of elliptical von Mises yield functions in stress-space. A previously developed and published 8-parameter model is well-suited for fitting a matched pair of longitudinal tension (LT) and hoop tension (HT) stress-strain curves as might typically be available from a strain-based pipeline design project. Fitting a pair of “target” LT-HT stress-strain curves is accomplished using a “2-root” fitting procedure where the roots correspond to locations where the yield functions intercept the stress axes in two-dimensional (longitudinal-hoop) stress space. In this paper, the previously described 8-parameter/2-root fitting procedure is extended to a 10-parameter/3-root fitting procedure for situations where a matched “triple” of pipe steel stress-strain curves are available (e.g., LT, HT and longitudinal compression or LC). This extension allows for analysis of strain-based design conditions using an analytical pipe steel, which provides an accurate representation of the uniaxial longitudinal and circumferential stress-strain response of the pipeline material. This paper reviews the 8-parameter/2-root fitting procedure and outlines the extension to the 10-parameter/3-root fitting approach including example application.

Probabilistic Structural Analysis for Advanced Space Propulsion Systems

1990 ◽  
Vol 112 (2) ◽  
pp. 251-260 ◽  
Author(s):  
T. A. Cruse ◽  
J. F. Unruh ◽  
Y.-T. Wu ◽  
S. V. Harren
Keyword(s):  
Structural Analysis ◽  
Material Behavior ◽  
Nonlinear Material ◽  
Significant Advance ◽  
Space Propulsion ◽  
Stress Strain ◽  
Ongoing Research ◽  
Strain Behavior ◽  
Nonlinear Stress ◽  
Random Material Properties

This paper reports on recent extensions to ongoing research into probabilistic structural analysis modeling of advanced space propulsion system hardware. The advances concern probabilistic dynamic loading, and probabilistic nonlinear material behavior. In both cases, the reported work represents a significant advance in the state-of-the-art for these topics. Random, or probabilistic loading is normally concerned with the loading described in power spectral density (PSD) terms. The current work describes a method for incorporating random PSD’s along with random material properties, damping, and structural geometry. The probabilistic material response is concerned with the prediction of nonlinear stress-strain behavior for physical processes that can be linked to the original microstructure of the material. Such variables as grain size and orientation, grain boundary strength, etc., are treated as random, initial variables in generating stochastic stress-strain curves. The methodology is demonstrated for a creep simulation.

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