基于M-K模型的成形极限预测及参数影响  

Theoretical prediction and parameter influence of FLDs based on M-K model

作　　者：杜平梅[1] 郎利辉[1] 刘宝胜[1] 张东星[1] 蔡高参[1] 

机构地区：[1]北京航空航天大学机械工程及自动化学院,北京100191

出　　处：《塑性工程学报》2011年第5期84-89,共6页Journal of Plasticity Engineering

基　　金：国家自然科学基金资助项目(50975014);华中科技大学材料成型与模具技术国家重点实验室开放基金资助项目(2010-T02)

摘　　要：基于M-K沟槽理论,对平面应力状态下各参数对板料的成形极限图的影响进行预测。将常温和高温的两种Swift修正本构引入成形极限的推导中,用Newton-Raphson迭代法求解得到理论预测的成形极限图。分别用5A90铝锂合金和TRIP钢的实际曲线与理论预测进行对比,确定了理论预测的准确性和可行性。基于此,对材料参数应变强化指数n、应变速率敏感性指数m、预应变ε0、温度T对成形极限图的影响进行了预测;同时,将修正的初始不均度引入推导中,结果表明,修正后的本构方程使理论预测更接近于真实的试验曲线。In this paper,the effect of various parameters on the forming-limit diagram（FLD）are comprehensively investigated on the basis of the Marciniak and Kuczynski theory.Under plane stress state,the predicted results of FLDs are calculated with the Newton-Raphson method and two hardening laws based on swift model has been applied.In addition,the experimental data from the FLDs tests of 5A90 Al-Li alloy and TRIP steel are compared with the predicted values in this test.It has verified the accuracy and feasibility of this method.The effects of the strain-hardening exponent（n-value）,strain-rate exponent（m-value）,prestrain（ε0-value） and temperature（T-value） on the FLDs were predicted,and it is shown that the forming limit strain increases with these parameters.Meanwhile,it indicates that the theoretical predictions are closer to the experimental data by using modified initial imperfection factor.

关 键 词：成形极限图 M-K模型 理论预测 本构方程 

分 类 号：O344.7[理学—固体力学] TG386[理学—力学]