单元类型和尺寸对裂尖疲劳塑性数值模拟的影响研究  

Influence of Element Type and Size on Finite Element Prediction of Crack Tip Plasticity

作　　者：赵丹[1] 冯淼林[1] 吴长春[1] 

机构地区：[1]上海交通大学工程力学系

出　　处：《力学季刊》2008年第3期349-355,共7页Chinese Quarterly of Mechanics

基　　金：国家自然科学基金(10772115)

摘　　要：本文采用Jiang-Sehitoglu循环塑性模型和多轴疲劳准则对紧凑拉伸式样裂尖的循环塑性变形、裂纹扩展速率和残余应力进行了有限元数值模拟,着重考察了单元的类型和最小单元尺寸对裂尖循环塑性和裂纹扩展速率的影响。紧凑拉伸试样的材料为1070钢,数值模拟采用了线性单元(四节点)和二次单元(八节点)两种单元,裂尖附近有限元单元的最小尺寸从0.007mm到0.24mm不等。文中将裂纹扩展速率的预测值与实验值进行了比较,通过对裂纹扩展速率的比较,确定在疲劳塑性分析时对单元类型和尺寸进行合理选取。The Jiang and Sehitoglu cyclic plasticity model combined with the multiaxial fatigue criterion was implemented into the finite element elastic - plastic stress analysis for the simulations of cyclic plasticity, crack growth and residual stress near the crack tip in a plane- stress compact specimen. The influence of element type and element size on the predicted cyclic plasticity near the crack tip and crack growth was studied. Material 1070 steel was used in the investigation. There are four node bilinear and eight node quadratic plane element used in the finite element simulations and the finest element size near the crack tip ranged from 0. 007mm to 0.24mm. The assessment of the influence of the element type and size was based upon the comparison of the predicted crack growth rate with experimental observation. Finally, the proper element type and element size in the fatigue plasticity analysis was introduced.

关 键 词：塑性模型 多轴疲劳准则 裂纹扩展 塑性变形 残余应力 

分 类 号：O346[理学—固体力学]