一种改进的损伤断裂准则及其在板料成形中的应用  

An improved damage fracture criterion and its application in sheet metal forming

作　　者：曾嵘[1] 黄亮[1] 李建军[1] 洪秀冬 

机构地区：[1]华中科技大学材料科学与工程学院材料成形与模具技术国家重点实验室,湖北武汉430074

出　　处：《锻压技术》2015年第8期13-20,共8页Forging & Stamping Technology

基　　金：国家自然科学基金资助项目(51105042);中央高校基本科研业务费资助项目(2012QN040)

摘　　要：将Lemaitre损伤断裂准则中的单轴应力状态的线性损伤修正为多轴应力状态的非线性损伤,并以铝合金5052-O筒形件冲压实验为例,揭示了工件的等效应力、等效塑性应变和单位体积损伤值分布规律,分析了模拟和试验成形件深度和壁厚的相对误差,用于评估改进的Lemaitre损伤断裂准则在板料成形工艺中的适用性。结果表明:在使用了改进的Lemaitre损伤断裂准则的筒形件冲压模拟中,工件的等效应力和等效塑性应变的最大值都出现在圆板与凸模圆角接触的区域,且材料的单位体积损伤值达到1的区域发生了破裂。采用改进的Lemaitre损伤断裂准则预测得到的成形深度误差和壁厚最大误差分别仅为6.5%和9.2%。The linear damage under uniaxial stress state in the Lemaitre damage fracture criterion was amended as the nonlinear damage under multi-axis stress states, and the cylindrical stamping experiment of aluminum alloy 5052 - 0 was set as an example. The distribution regularity of the equivalent stress, the equivalent plastic strain and the damage per volume were revealed. The relative errors of the forming depth and the wall thickness in simulations and experiments were analyzed, which were used to evaluate applicability of the modi- fied Lemaitre damage fracture criterion in the sheet metal forming process. The results show that the maximum values of the equivalent stress and the equivalent plastic strain appear at the contact area of the circular plate and the punch when the modified Lemaitre damage fracture criterion is used in the simulations of cylindrical stamping process. Furthermore, stamping parts occur fracture at where the damage value per volume reaches 1. The relative error of the forming depth and the maximum relative error of the wall thickness predicted by the modified Lemaitre damage fracture criterion are only 6. 5% and 9. 2%, respectively.

关 键 词：材料损伤断裂 板料成形 铝合金 有限元法 

分 类 号：TG386[金属学及工艺—金属压力加工]