Yield conditions for incompressible isotropic and orthotropic materials with different yield stress in tension and compression

Meccanica ◽  
1967 ◽  
Vol 2 (2) ◽  
pp. 118-125 ◽  
Author(s):  
Michele Capurso
Keyword(s):  
Yield Stress ◽  
Orthotropic Materials ◽  
Tension And Compression ◽  
Isotropic And Orthotropic Materials ◽  
Yield Conditions

Isoparametric Graded Finite Elements for Nonhomogeneous Isotropic and Orthotropic Materials

2002 ◽  
Vol 69 (4) ◽  
pp. 502-514 ◽  
Author(s):  
Jeong-Ho Kim ◽  
G. H. Paulino
Keyword(s):  
Finite Elements ◽  
Material Property ◽  
Poisson’S Ratio ◽  
Orthotropic Plate ◽  
Poisson's Ratio ◽  
Orthotropic Materials ◽  
Finite Width ◽  
Infinite Length ◽  
Graded Materials ◽  
Isotropic And Orthotropic Materials

Graded finite elements are presented within the framework of a generalized isoparametric formulation. Such elements possess a spatially varying material property field, e.g. Young’s modulus E and Poisson’s ratio ν for isotropic materials; and principal Young’s moduli E11,E22, in-plane shear modulus G12, and Poisson’s ratio ν12 for orthotropic materials. To investigate the influence of material property variation, both exponentially and linearly graded materials are considered and compared. Several boundary value problems involving continuously nonhomogeneous isotropic and orthotropic materials are solved, and the performance of graded elements is compared to that of conventional homogeneous elements with reference to analytical solutions. Such solutions are obtained for an orthotropic plate of infinite length and finite width subjected to various loading conditions. The corresponding solutions for an isotropic plate are obtained from those for the orthotropic plate. In general, graded finite elements provide more accurate local stress than conventional homogeneous elements, however, such may not be the case for four-node quadrilateral (Q4) elements. The framework described here can serve as the basis for further investigations such as thermal and dynamic problems in functionally graded materials.

YIELD STRESS BASED ON NATURAL STRAIN THEORY UNDER CYCLIC TENSION-COMPRESSION LOAD AFTER LARGE SIMPLE SHEAR

2018 ◽  
Vol 5 (2) ◽  
Author(s):  
Yasuyuki Kato ◽  
Hiroki Uchida
Keyword(s):  
Yield Stress ◽  
Uniaxial Tension ◽  
Simple Shear ◽  
Strain Theory ◽  
Experimental Result ◽  
Cyclic Loads ◽  
Yield Behavior ◽  
Compression Load ◽  
Natural Strain ◽  
Tension And Compression

Many researches on the yield behavior under cyclic loads have been conducted for many years. However, almost these studies have been done within the range of relatively small size deformation. Hence, the detailed studies for yield phenomenon under cyclic loads after applying a large pre-deformation have not been sufficiently elucidated. Therefore, in the series of our studies, using test pieces of high purity tough pitch copper, the yield behavior generated under cyclic loads after applying the predeformation of large uniaxial tension or large simple shear have been investigated. However, as for the case that the type of pre-deformation differs from the type of deformation in the cyclic load, detailed studies have not been conducted yet. Hence, in the present study, the yield behavior generated under cyclic loads for tension and compression after applying a large pre-deformation of simple shear is examined based on Natural Strain theory. Furthermore, experimental results in the present study are compared with results of previous studies concerning cyclic loads for tension and compression after applying the large uniaxial tension. Consequently, it is revealed that the decreasing tendency of yield stress at the compression side appears more strongly as compared with the experimental result by previous study that the pre-deformity is a uniaxial tension.

scholarly journals Yield Stress Anomaly in B2 FeAl

1996 ◽  
Vol 460 ◽  
Author(s):  
K. Yoshimi ◽  
S. Hanada ◽  
M. H. Yoo
Keyword(s):  
Single Crystals ◽  
Yield Stress ◽  
Rate Sensitivity ◽  
Recovery Process ◽  
Peak Temperature ◽  
Positive Temperature ◽  
Slip Vector ◽  
Temperature Range ◽  
Tension And Compression ◽  
Increasing Temperature

ABSTRACTOur studies on yield stress anomaly of B2 FeAI single crystals are reviewed in this paper. A positive temperature dependence of yield stress, so-called “yield stress anomaly”, is observed in B2 FeAI in which excess vacancies are fully annealed out. Associated with the anomaly, characteristic asymmetry is found between tension and compression. While the strain-rate sensitivity is almost zero in the temperature range of the yield stress anomaly, the stress relaxation becomes significant with increasing temperature, indicating that a recovery process is thermally activated. It is ascertained by the two-surface trace analysis that slip transition from <111> direction at intermediate temperature to <100> at high temperature occurs around the peak temperature. Even at the peak temperature, in addition, operative slip vector for yielding is confirmed to be predominantly <111> by TEM. Also, it is observed that <111>-type superdislocations are frequently climb-dissociated in the temperature range of the anomaly. APB formation on {111} plane is energetically favorable, which is in agreement with the Flinn's calculation for the B2 superlattice that APB energy on {111} plane is lower than that on {110} plane. Such an anisotropy of APB energy would offer specific driving force for the climb dissociation on <111> superdislocations. On the basis of the observed results, the anomalous strengthening behavior of B2 FeAI single crystals is discussed.

A Fracture Theory for Brittle Anisotropic Materials

1974 ◽  
Vol 96 (2) ◽  
pp. 91-96 ◽  
Author(s):  
T. G. Priddy
Keyword(s):  
Orthotropic Materials ◽  
Necessary Condition ◽  
Material Strength ◽  
Interaction Coefficients ◽  
Cubic Equation ◽  
Simple Cubic ◽  
Failure Theory ◽  
Tension And Compression ◽  
Fracture Theory ◽  
Macroscopic Failure

This paper outlines the development of a general macroscopic failure theory. The result is a relatively simple cubic equation where interaction coefficients for tension-tension and compression-compression strengths may be defined separately. Approximations for biaxial and triaxial normal stress interactions are included to reduce the number of experimental data to nine for brittle three-dimensionally orthotropic materials and to two for brittle isotropic materials. A necessary condition that the theory closely describe brittle isotropic material strength is satisfied for a comprehensive set of cast iron biaxial strength data. The surface is graphically illustrated for various materials.

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