NONLINEAR UNIAXIAL INTEGRAL CONSTITUTIVE EQUATION INCORPORATING RATE EFFECTS, CREEP AND RELAXATION

被引:62
作者
CERNOCKY, EP
KREMPL, E
机构
[1] Department of Mechanical Engineering, Aeronautical Engineering and Mechanics. Rensselaer Polytechnic Institute, Troy
基金
美国国家科学基金会;
关键词
D O I
10.1016/0020-7462(79)90035-0
中图分类号
O3 [力学];
学科分类号
08 ; 0801 ;
摘要
A previously proposed first order non-linear differential equation for uniaxial viscoplasticity, which is non-linear in stress and strain but linear in stress and strain rates, is transformed into an equivalent integral equation. The proposed equation employs total strain only and is symmetric with respect to the origin and applies for tension and compression. The limiting behavior for large strains and large times for monotonic, creep and relaxation loading is investigated and appropriate limits are obtained. When the equation is specialized to an overstress model it is qualitatively shown to reproduce key features of viscoplastic behavior. These include: initial linear elastic or linear viscoelastic response: immediate elastic slope for a large instantaneous change in strain rate normal strain rate sensitivity and non-linear spacing of the stress-strain curves obtained at various strain rates; and primary and secondary creep and relaxation such that the creep (relaxation) curves do not cross. Isochronous creep curves are also considered. Other specializations yield wavy stress-strain curves and inverse strain rate sensitivity. For cyclic loading the model must be modified to account for history dependence in the sense of plasticity. © 1979.
引用
收藏
页码:183 / 203
页数:21
相关论文
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