摘要
将拉伸均匀变形阶段应力-应变的外推曲线作为初始本构关系，通过反复迭代拟合载荷一位移曲线来确定真实本构关系，很大程度上提升了材料模型的可靠性。采用试验与有限元模拟相结合的方法来研究缺口试样的断裂情况，获得了不同应力状态下应力三轴度与断裂应变间的关系曲线，并以此作为材料发生韧性断裂的判据。将基于拉伸试验获得的材料模型应用于剪切有限元模拟中来预测断面质量，采用ALE方法来提高单元网格质量，利用单元删除法来模拟裂纹的萌生与扩展，分析了剪切机制与损伤分布。最后，对冲裁断面形貌进行试验验证，模拟结果与剪切试验结果吻合程度高。
An initial constitutive relationship was obtained through extrapolating the stress-strain curve in the uniform deformation stage of tensile experiment, the initial force-displacement curve was iterative fitted to confirm the true constitutive relationship, which improves the reliability of the material model to a great extent. A combined experiment and finite element method was developed to make a research on the fracture condition of different notched specimens, the relationship between stress triaxiality and fracture strain under various stress states was obtained which is taken as a criterion of ductile fracture. Material model derived from the tensile test with the ductile fracture criterion was applied in finite element simulation of shearing process to predict the feature of sheared edges. Mesh quality optimization was achieved by adopting ALE method and the element deletion method was used to simulate the initiation and growth of crack. The shearing mechanism and damage distribution were analyzed. Finally, the simulated sheared quality was verified by experiment, and the simulation results agreed well with the experimental one.
作者
刘倩
韩静涛
郑小平
张荣华
田亚强
LIU Qian;HAN Jing-tao;ZHENG Xiao-ping;ZHANG Rong-hua;TIAN Ya-qiang(Key Laboratory of the Ministry of Education for Modem Metallurgy Technology, College of Metallurgy and Energy, North China University of Science and Technology, Tangshan 063210, China;School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China)
出处
《塑性工程学报》
CAS
CSCD
北大核心
2018年第2期57-64,共8页
Journal of Plasticity Engineering
基金
河北省自然科学基金资助项目(E2018209278)
关键词
本构关系
应力三轴度
断裂准则
剪切工艺
缺口试样
拉伸试验
constitutive relationship
stress triaxiality
ductile fracture criterion
shearing process
notched specimen
tensile experi-ment
