Mechanical Deformation Modeling of Diamond/Gaas Structures

1996 ◽  
Vol 445 ◽  
Author(s):  
Nickolaos Strifas ◽  
Aris Christou

AbstractIn this study a finite strain elastic-plastic finite element analysis is performed on diamond/GaAs structures. A series of models based upon the principal of superposition are proposed to investigate the mechanical deformation and thermal stress behavior of the diamond/gas structure due to coefficients of thermal expansions (CTE) mismatches. The interfacial shear and peeling stresses in multilayered stacks subjected to uniform temperature variation are studied. Finite strain elastic – plastic analysis is performed on a crack which lies on the interface between the diamond and gas materials. The ductile fracture from the tip of the interface crack, the stress and strain fields and distribution of microvoid volume fraction are analyzed.

Author(s):  
C. Dumitras ◽  
I. Cozminca

The electromagnetic forming has the advantage of a minimum forming time, but this is a major obstacle in determining the process’s history of the forming workpiece. Both experimental and theoretical known analysis methods for this process give a discret array of data (only for the displacements). One considers it is more adequate to use the finite element method in studying this process. The main advantage of the finite element analysis is given by the fact that it shows the stress and strain fields in a continuous way during the deformation process. Also, it offers a model from which one can predict the final shape of the part and the possible crack zones. One present a compared study of the experimental and the simulated results achieved of the free bulging aluminum specimens by electromagnetic impulses.


2019 ◽  
Vol 962 ◽  
pp. 210-217
Author(s):  
Yong Ming Guo ◽  
Nozomi Fukae

It is well known that the properties of materials are a function of their microstructural parameters. The FEM is a good selection for studies of three-dimensional microstructure-property relationships. In this research, the elastic-plastic micromechanical response of the particle volume fraction of two-phase materials have been calculated using a commercial software package of the FEM, some new knowledges on the microstructure-property relationships have obtained.


2013 ◽  
Vol 351-352 ◽  
pp. 854-859 ◽  
Author(s):  
Fan Wang ◽  
Zhi Feng Luo ◽  
Sheng Hao Mo

The article introduces the application of the large universally used finite element analysis software ABAQUS in elastic-plastic analysis of the cast-steel joints in building structure. Using the cast-steel joint of a large reticulated shell structure in Shenzhen as an example, the article explains how to import the joint model into ABAQUS and start the finite element analysis, and finally get the elastic-plastic analysis results, thus provide the reference for engineering design, analysis and optimize design of cast-steel joints.


1992 ◽  
Vol 114 (2) ◽  
pp. 222-228 ◽  
Author(s):  
W. Jiang

This paper is concerned with the elastic-plastic analysis of tubes subjected to variable loads. The yield condition for a material having residual stress and strain is first derived. Then by incremental method, the stresses and strains of the tube at any loading stage can be found. A closed-form solution is achieved as an example of tubes incurring ratchetting, and a general program is developed to make the theory applicable to complex loading situations.


1997 ◽  
Vol 119 (2) ◽  
pp. 332-341 ◽  
Author(s):  
E. R. Kral ◽  
K. Komvopoulos

A three-dimensional finite element analysis of a rigid sphere sliding on an elastic-plastic layered medium is presented. Results for the subsurface stress and strain fields are given for a perfectly adhering layer with an elastic modulus and yield stress both two and four times that of the substrate, and contact loads 100 and 200 times the initial yield load of the substrate material. Sliding is simulated to distances of approximately two to three times the initial contact radius. The sphere is modeled by contact elements, and the interface friction coefficient is assumed equal to 0.1 and 0.25. The effects of layer material properties, contact friction, and normal load on the sliding and residual stresses in the layer and the substrate are examined. The distributions of tensile stresses in the layered medium and shear stresses at the layer/substrate interface are presented and their significance for crack initiation and layer decohesion is discussed. Reyielding during unloading is also analyzed for different material properties and contact loads.


2021 ◽  
Author(s):  
Steven M. Smith ◽  
David N. Hutula

Abstract The Twice-Yield method is an elastic-plastic finite element analysis (FEA) pioneered by Professor Arturs Kalnins at Lehigh University which approximates the stabilized cyclic response that would otherwise be obtained from a cycle-by-cycle elastic-plastic FEA. The Twice-Yield method is used to evaluate the load range conditions which occur between any two load states from the stabilized cyclic structural response. The rigorous implementation of the Twice-Yield method requires special handling of material properties. In particular, the method requires the average of the properties corresponding to the two load states. This paper documents a detailed technical basis of the Twice-Yield method’s implementation in Abaqus including the special handling of material properties. An assessment of the Twice-Yield method is performed based on analyzing a thermally shocked stepped pipe. Included in the assessment are comparisons of the cycle-by-cycle elastic-plastic FEA results and the Twice-Yield method elastic-plastic FEA results. The comparisons show the efficacy of the Twice-Yield method as a viable cyclic elastic-plastic analysis method.


2015 ◽  
Vol 12 (05) ◽  
pp. 1550030 ◽  
Author(s):  
Satyanarayan Patel ◽  
Rahul Vaish ◽  
Vishal Singh Chauhan ◽  
Chris Bowen

Object Oriented Finite Element Analysis (OOF2) is used to predict the thermal and mechanical properties of Al – MgO composites. In this work, three compositions of composites containing 5%, 10% and 15% MgO (by volume) are studied. The influence of MgO volume fraction is examined in terms of effective Young's modulus and coefficient of thermal expansion of the composites. In addition, the stress and strain contours are plotted, which are helpful to understand the mechanical behavior of these composites. It is noted that the properties of composites are improved because of the presence of MgO . However, local stresses increase with filler content.


1975 ◽  
Vol 42 (2) ◽  
pp. 269-273 ◽  
Author(s):  
S. N. Atluri ◽  
A. S. Kobayashi ◽  
J. S. Cheng

This paper deals with the finite-strain, finite-element analysis of the states of stress and strain in the vicinity of a blunt indenter applied to the exposed surface of the pia-arachnoid of an anesthetized rhesus monkey.


Author(s):  
Nobuyoshi Yanagida ◽  
Masaaki Tanaka ◽  
Norimichi Yamashita ◽  
Yukinori Yamamoto

Alternative stress evaluation criteria suitable for Finite Element Analysis (FEA) proposed by Okamoto et al. [1],[2] have been studied by the Committee on Three Dimensional Finite Element Stress Evaluation (C-TDF) in Japan. Thermal stress ratchet criteria in plastic FEA are now under consideration. Two criteria are proposed: (1) Evaluating variations in plastic strain increments, and (2) Evaluating the width of the area in which Mises equivalent stress exceeds 3Sm. To verify of these criteria, we selected notched cylindrical vessel models as prime elements. To evaluate the effect of the local peak stress distribution on these criteria, cylindrical vessels with a semicircular notch on the outer surface were selected for this analysis. We used two notch configurations for our analysis, and the stress concentration factor for the notches was set to 1.5 and 2.0. We conducted elastic-plastic analysis to evaluate the ratchet limit. Sustained pressure and alternating enforced longitudinal displacements which causes secondary stress were used as parameters for the elastic-plastic analysis. We found that when no ratchet was observed, the equivalent plastic strain increments decreased and the area in which Mises equivalent stress exceeds 3Sm are below the certain range.


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