材料三剪屈服准则研究

RESEARCH ON TRIPLE-SHEAR YIELD CRITERION FOR MATERIALS

在分析Tresca屈服准则和双剪屈服准则的基础上,通过考虑十二面体单元主剪面上所有三个主剪应力的共同作用,提出了材料的三剪屈服准则,并对该准则作了极限线分析、应力莫尔圆分析、中间主应力效应曲线分析和滑移面方向分析。结果表明,新准则与统一屈服准则一样表示的是一个屈服准则系列,其中Tresca屈服准则和vonMise屈服准则是该屈服准则的特例。但与双剪统一屈服准则不同,新屈服准则的极限线和中间主应力效应曲线是非线性的,能够描述材料的非线性屈服特性。另外,也克服了双剪统一屈服准则中存在的在某些特定应力状态下会得出双重滑移面并且滑移面方向会发生变化的问题。

A triple-shear yield criterion is proposed through analyzing the Tresca yield criterion and the twin-shear yield criterion by taking account of the combined actions of all three principal shear stresses acting on the dodecahedron element. The loci on the n plane and （σ1,σ2） plane, the Mohr circles on the （σ, τ） plane, the effective curves with the intermediates principal stress, and the slip directions are analyzed for it. Similar to the unified yield criterion, the proposed criterion can represent a series of yield criteria in which the Tresca yield criterion and the von Mises yield criterion are only its special cases. The lociand the effective curves of the criterion are of nonlinear types that could give a better description to the yield characteristics of materials. On the other hand, this criterion overcomes the disadvantages of the twin-shear yield criterion with double slip planes and sudden changes of slip directions when materials are in some special stress states.