一种新的耦合GTN模型以精确识别金属板料极限应变的三维M-K模型  

A novel three-dimensional M-K model by integrating GTN model for accurately identifying limit strains of sheet metal

作　　者：王玉宝 张存生[1] 孟子杰 陈良[1] 赵国群[1] Yu-bao WANG;Cun-sheng ZHANG;Zi-jie MENG;Liang CHEN;Guo-qun ZHAO(Key Laboratory for Liquid−Solid Structural Evolution&Processing of Materials(Ministry of Education),Shandong University,Jinan 250061,China)

机构地区：[1]山东大学材料液固结构演变与加工教育部重点实验室,济南250061

出　　处：《Transactions of Nonferrous Metals Society of China》2023年第7期1953-1962,共10页中国有色金属学报（英文版）

基　　金：supported by the National Natural Science Foundation of China (No.51975330);Key Research and Development Program of Shandong Province,China (No.2021ZLGX01);Project of Colleges and Universities Innovation Team of Jinan City,China (No.2021GXRC030)。

摘　　要：为了精确识别金属板料的极限应变并提高成形极限预测精度,建立了一种新的耦合GTN模型的三维M-K模型,并命名为三维M-K-GTN模型。首先,通过引入摩擦应力和沿厚度方向上的法向应力,对经典M-K模型进行修正以使其适用于三维应力状态。随后,嵌入GTN模型以取代经验失效准则,将凹槽内孔洞体积分数累积到临界值时的应变作为极限应变。此外,考虑法向应力和摩擦应力,修正了孔洞形核与长大表达式。最后,预测成形极限曲线与实验获得的AA6016-T4板料极限应变的对比结果表明,三维M-K-GTN模型解决了大应变路径下预测结果明显高估的问题,且在每个给定的应变路径下都具有较高的预测精度。To accurately identify the limit strains and improve the prediction accuracy of forming limits for sheet metal,a novel three-dimensional M-K model by integrating GTN model is developed and named 3D M-K-GTN model.By introducing the through-thickness normal stress and friction stress,the original M-K model is extended for adapting to the three-dimensional stress state.Furthermore,the empirical failure criterion is replaced by integrating the GTN model,and thus the limit strain is identified when the void volume fraction within the groove accumulates to a critical value.Besides,the voids nucleation and growth expressions are also re-derived and modified by embedding the friction stress and normal stress.Finally,the comparison between predicted forming limit curves and experimental limit strains of AA6016-T4 sheet indicates that the 3D M-K-GTN model solves the significant overestimation of prediction results under large strain paths,and always provides a high prediction accuracy for each strain path given.

关 键 词：极限应变识别 孔洞演化 失效准则 三维M-K-GTN模型 预测精度 

分 类 号：TG113.25[金属学及工艺—物理冶金]