有限变形伪弹性合金直至失效破坏的全程模拟

发布时间：2019-04-22 08:38

【摘要】：本文提出热力学一致新弹塑性本构模型,用来全面模拟形状记忆合金(SMAs)在伪弹性温度范围内的有限变形行为,包括初始不可恢复小弹塑性变形阶段,可恢复有限变形伪弹性阶段,部分恢复大变形强化阶段以及最后的失效破坏阶段。其中考虑了伪弹性阶段的拉伸-压缩不对称性质。本文提出新的直接方法,基于单轴实验数据,获得本构模型中多轴强化模量和应力强度的显式表达,由此所建立的弹塑性模型可以自动拟合涉及初始塑性变形,伪弹性滞回圈,塑性变形以及失效破坏行为等四阶段的实验数据。本文与先前模型相比,有如下三个创新点:1.基于经典的弹塑性模型,避免了考虑马氏体-奥氏体相变微观机制以及微观-宏观平均等一系列复杂步骤;2.可以同时模拟伪弹性合金的伪弹性,塑性以及失效破坏等行为;3.模型中本构量可以由表征单轴应力-应变曲线的任意形函数显式表达,对所有类型伪弹性合金具有普适性。
[Abstract]:In this paper, a new thermodynamically consistent elastoplastic constitutive model is proposed to simulate the finite deformation behavior of shape memory alloy (SMAs) in the pseudo elastic temperature range, including the initial unrecoverable small elastoplastic deformation stage. The finite deformation pseudo elastic stage, the partial recovery large deformation strengthening stage and the final failure stage can be recovered. The tensile-compression asymmetries in the pseudo-elastic phase are considered. In this paper, a new direct method is proposed. Based on uniaxial experimental data, the explicit expressions of multiaxial strengthening modulus and stress intensity in constitutive model are obtained. The elasto-plastic model can automatically fit the initial plastic deformation and pseudo-elastic hysteresis loop, and the elastic-plastic model can be used to simulate the initial plastic deformation and pseudo-elastic hysteresis loop. Four-stage experimental data of plastic deformation and failure behavior. Compared with the previous model, this paper has three innovations as follows: 1. Based on the classical elasto-plastic model, a series of complex steps, such as considering the micro-mechanism of martensite-austenite transformation and micro-macro average, are avoided. The pseudo-elastic, plastic and failure behaviors of pseudo-elastic alloys can be simulated at the same time; 3. The structure in the model can be expressed explicitly by any shape function representing uniaxial stress-strain curves, which is universal to all types of pseudo-elastic alloys.
【学位授予单位】：上海大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TG139.6

【相似文献】