各向异性本构关系的测量

为确定三种不同金属薄板材料的本构关系,进行了多种简单拉伸实验和平面应变实验,并应用了SIMPLEX数值拟合法.对应每种应变率的简单拉伸实验,都用几种不同的硬化模型进行了拟合.阶跃实验揭示了不同的应变率效应.通过比较简单拉伸曲线和平面应变曲线,证明对于这些实验材料,Hill的等向硬化新理论是一种比较合理的模型.综合各种因素而得到的本构关系及屈服准则,可用于国冲头类型冲压实验的有限元分析中.

Measurement of Anisotropic Constitutive Equation

Multiple tensile and plane-strain tests have been performed and a simplex numerical fitting me thod employed to generate the constitutive equations for three different sheet steel materials. These equations are needed for analysj s of simple stamping operation sby the finite element method. Several work-hardening laws were examined a t each strain rale. Jump te s ts reveal differen t ra le effec ts, a s no led el sewhere. Compaison of hardening in plane strain and in uniaxial tension suggests that Hill's new theory with iso tropic hardening is a reasonable model of these materials. The combination of scalar hardening as a function of effective strain and strain ra te coupled with them ul ti-axial model is sufficiently detailed to allow reasonable analysis of dome-type te s ts.