应变硬化和应变速率敏感材料在单向拉伸状态的塑性分析

对于即具有应变速率敏感，又具有应变强化效应的材料在单向应力拉伸的塑性流动及失稳分析，本文证明了Hart的分析的基础相同于Hutchinson等基于流动方程b＝Kε{sup}nε{sup}m的分析。然后，以Hart的分析为出发点，对Hart提出的流动稳定性及其判据（及JHC判据）给予讨论。表明Hart的流动稳定性判据适用于力学缺陷，并主要地依赖于应变硬化指数。在Hart的分析基础上，考虑到初始几何缺陷2（0），对失稳过程给予增量分析和积分分析。增量分析给出了m和δ之间的（及n≠0的）简明关系：δ＝（1/α （0））{sup}m－1，δ＝（1/α （0））{sup}me{sup}n－1，积分分析得到了和Hutchinson等及Ghosh的“非线性长波分析”得到的积分关系在n＝0的情况下相同的结果。将这些关系和实验结果比较，吻合是好的。此外，对载荷的分析给出了恒定十字头速度L及恒定应变速度ε的载荷表达式。

ANALYSIS ON PLASTICITY IN MATERIALS WITH STRAIN HARDENING AND STRAIN-RATE SENSITIVITY UNDER UNIAXIAL TENSION

For the analysis of plastic flow and necking development of the materials with both work hardening and Strain-rate sensitivity under uniaxil tension, this paper proves that the basis of Hart’s analysis is as same as Hutchinson etal’s analysis based on constitutive law b＝Kε{sup}nεThen, based on Hart’s analysis，the flow stability and the criterion of stability of Hart and Jonas etal are discussed. Also, considering the initial geometric imperfection（a0），the incremental and the integral analysis are given for necking development respectively. From the increment analysis, relation between the total elongationδand m as well n are given as；The result of the integral analysis is as same as the integral expression (when n=0)derived by Hutchinson etal. Comparing these theorial results with experimen Tal resnlts, the coincidence is good, In addition, the load analysis is made and two load expressions are given,one is for constant L, the other is for constant.