【作者】 周维；

【导师】 伍先安；

【作者基本信息】 北京化工大学 ， 工程力学， 2009， 硕士

【摘要】 一般说来,所有材料的变形都与所经历的时间历程有关,在非弹性变形中总有时间带来的影响。在这篇论文中,对亚加载面模型的扩展研究可推导出一个能够描述在广应力范围内时间依赖性的材料变形,这是对前人研究的继续发展。本研究是以亚加载面模型理论为基础,在对历来典型的粘弹塑性模型分析的基础上,提出了金属材料的时间依赖性—亚加载面模型。它是采用分离型模型的概念,提出考虑金属材料高温条件下时间倚赖性变形特性的蠕变方程结构函数,从而推导出具体的本构方程式。亚加载面模型能合理地表现单调和重复负载的弹塑性变形特性,而且能较好的表现Masing效果。对2 1/4Cr-1Mo钢在高温(600摄氏度)下的不同应变速率的实验结果进行数值模拟解析,初步验证了此本构方程模型的合理性。本文扩展了亚加载面模型的应用范围,可用来描述亚加载面不断膨胀直到达到标准屈服面的时间依赖性变形行为,而且引入了随时间变化而变化的蠕变方程式,这就是时间依赖性的亚加载面模型的形成过程。它在弹塑性蠕变结构方程的基础上更进一步,在这个基础上,可得出金属的各向同性结构方程、蠕变方程等。将此引入有限元法中,开发金属机械构造物的粘弹塑性模型的数值解析程式,与实验数值进行模拟比较,对不完善的方面进行修正、补充,从而完成实用程序。更多还原

【Abstract】 Generally speaking,characteristics of all materials have something to do with the time history they have experienced,there are always impact caused by time in inelastic deformation.In this paper,the continuing study of subloading surface model can deduce a material deformation described by time-dependent in the range of extensive stress,which is the continuous development based on previous research.The research is based on the subloading surface model theory,and typical analysis history of elasto-viscoplatic model are considered simultaneously,propose a time-dependent subloading surface model of metal materials.It adopts the concept of separated type model,presents the structural function in creep equation of deformation which takes into account the time-dependent when metal materials are under high temperature condition,thus obtains the specific constitutive equations. Subloading surface model can reasonably represent the elastic- plastic deformation characteristic of both the changeless and repeated load,and also Masing Effect.The paper analyze the numerical simulation of test results presenting different strain rates obtained by putting 2 1/4 Cr-1Mo steel under high temperature(600 degree centigrade),which serves as a preliminary identification for the reasonability of above constitutive equations.This paper expands the application range of subloading surface model,and it can also be used to describe the time-dependent deformation behaviors of subloading surface during its continuous expansion until reaching normal-yield surface,meanwhile introduces the creep equations which varies with time,that is the forming process of time-dependent Subloading surface model.It steps further on the basis of elastic-plastic creep structure equations,then obtains metals’ isotropy structure equations,creep equations.etc.Introduce the above into finite element method,develop numerical analysis equations of elasto-viscoplatic model for metal mechanical structures,make simulation comparisons with experimental data in order to do some correction and supplement to imperfect places,thus complete the whole practical program.更多还原