New approach to the generation of orthogonal body-fitted meshes and its application to non-steady plane-strain ideal plastic flow

Author(s):  
Shu-Peng Cai ◽  
Zhong-Jin Wang
2005 ◽  
Vol 21 (7) ◽  
pp. 1322-1345 ◽  
Author(s):  
K CHUNG ◽  
W LEE ◽  
O RICHMOND ◽  
S ALEXANDROV

2007 ◽  
Vol 340-341 ◽  
pp. 211-216
Author(s):  
Mitsutoshi Kuroda

In this study, effects of typical texture components observed in rolled aluminum alloy sheets (i.e. Copper, Brass, S, Cube and Goss texture components) on plastic flow localization are studied. The material response is described by a generalized Taylor-type polycrystal model, in which each grain is characterized in terms of an elastic-viscoplastic continuum slip constitutive relation. First, forming limits of thin sheet set by sheet necking are predicted using a Marciniak–Kuczynski (M–K-) type approach. It is shown that only the Cube texture component yields forming limits higher than that for a random texture in the biaxial stretch range. Next, three-dimensional shear band analyses are performed, using a three-dimensional version of M–K-type model, but the overall deformation mode is restricted to a plane strain state. From this simple model analysis, two important quantities regarding shear band formation are obtained: i.e. the critical strain at the onset of shear banding and the corresponding orientation of shear band. It is concluded that the Cube texture component is said to be a shear band free texture, while some texture components exhibit significantly low resistance to shear band formation. Finally, shear band developments in plane strain pure bending of sheet specimens with the typical textures are studied.


1997 ◽  
Vol 20 (1) ◽  
pp. 165-186
Author(s):  
F. Labropulu ◽  
O. P. Chandna

A new approach for the determination of exact solutions of steady plane infinitely conductingMHDaligned flows is presented. In this approach, the(ξ,ψ)- or the(η,ψ)- coordinates is used to obtain exact solutions of these flows whereψ=(x,y)is the streamfunction andw=ξ(x,y)+iη(x,y)is an analytic function ofz=x+iy.


It is usual to regard glass as a purely brittle solid and this has been taken for granted in almost all past papers on the mechanical strength, static fatigue, and ageing properties of glasses. However, in the present note this approach is rejected as being incompatible with experimental evidence of plastic flow in glass, and incapable of explaining the strengths observed. Instead a completely new approach is attempted in which glass is treated as an elastic-plastic solid and a complete theory of glass flow and strength is developed. The note summarizes the contents of three papers soon to be published which develop these ideas in more detail, and readers are referred to these three papers (Marsh 1964 a , b , c ) for full experimental and theoretical support of the ideas presented here. In brittle fracture theory glass is expected to exhibit its theoretical cohesive strength if it is flaw-free (e. g. untouched glass fibre), but if handled surface cracks are introduced and the strength should fall to a value predicted either by the Griffith (1920) energy balance equation or by the known stress concentration factor at the crack tip. Secondary effects such as static fatigue and ageing can then be explained as stress corrosion phenomena.


2005 ◽  
Vol 495-497 ◽  
pp. 69-76 ◽  
Author(s):  
X.B. Wang

Peak strength, mechanical behavior, and shear band (SB) of anisotropic jointed rock (JR) were modeled by Fast Lagrangian Analysis of Continua (FLAC). The failure criterion of rock was a composite Mohr-Coulomb criterion with tension cut-off and the post-peak constitutive relation was linear strain-softening. An inclined joint was treated as square elements of ideal plastic material beyond the peak strength. A FISH function was written to find automatically elements in the joint. For the lower or higher joint inclination (JI), the higher peak strength and more apparent strain-softening behavior are observed; the failure of JR is due to the slip along the joint and the new generated SBs initiated at joint’s two ends. For the lower JI, the slope of softening branch of stress-strain curve is not concerned with JI since the new and longer SBs’s inclination is not dependent on JI, as can be qualitatively explained by previous analytical solution of post-peak slope of stress-strain curve for rock specimen subjected to shear failure in uniaxial compression based on gradient-dependent plasticity. For the higher JI, the post-peak stress-strain curve becomes steeper as JI increases since the contribution of the new SBs undergoing strain-softening behavior to axial strain of JR increases with JI. For the moderate JI, the lower strength and ideal plastic behavior beyond the elastic stage are found, reflecting that the inclined joint governs the deformation of JR. The present numerical prediction on anisotropic peak strength in plane strain compression qualitatively agrees with triaxial experimental tests of many kinds of rocks. Comparison of the present numerical prediction on JI corresponding to the minimum peak strength of JR and the oversimplified theoretical result by Jaeger shows that Jaeger’s formula has overestimated the value of JI.


1956 ◽  
Vol 23 (3) ◽  
pp. 444-450
Author(s):  
L. W. Hu

Abstract This investigation deals with a study of the plastic behavior of anisotropic metals. By extending Hill’s theory of plastic flow of anisotropic metals, plastic stress-strain relations for anisotropic materials with strain hardening are developed. Applications of these relations are also made to plane-stress and plane-strain problems with anisotropy. The effect of anisotropy on the stress distribution and on the pressure to produce yielding in a thick-walled cylinder under internal pressure is discussed. The influence of anisotropy on the interpretation of conventional biaxial tension-tension and tension-torsion tests is also considered in this study.


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