高强钢TRB盒形件热冲压成形极限预测研究

发布时间：2018-07-03 13:15

本文选题：高强钢 + 连续轧制变截面板　；参考：《哈尔滨工业大学》2017年硕士论文

【摘要】：随着汽车的轻量化、安全性和防撞性能要求越来越高,采用热冲压成形将高强钢连续轧制变截面板(Tailor Rolled Blanks,TRB)应用于汽车零部件的生产技术应运而生,其生产的零部件根据不同部位的承载能力需求具有不同的厚度,可以从材料和结构双重角度上实现汽车轻量化。但TRB厚度具有不均匀性,其热冲压成形过程中零件的破裂和起皱等缺陷比较突出,因此对高强钢TRB热冲压的成形极限进行深入研究尤为重要,而以盒形件为典型件研究其成形极限对探讨其他复杂汽车覆盖件的的成形极限具有普遍指导意义。根据B1500HS热拉伸应力-应变曲线建立了高强钢TRB与温度、应变速率和厚度相关的本构关系模型。以连续损伤力学和细观损伤力学为基础,推导出高强钢B1500HS TRB热成形的Lemaitre和Rice-Tracey韧性断裂准则,通过数值模拟与试验相结合的方法求取了韧性断裂准则中的材料参数。利用ABAQUS进行了不同压边力、TRB板厚差、TRB过渡区长度下的高强钢TRB盒形件热冲压成形数值模拟。基于韧性断裂准则对ABAQUS进行了二次开发,将韧性损伤模型嵌入数值模拟结果中得到了不同热冲压条件下高强钢TRB盒形件的热冲压成形极限预测值。设计了试验模具和TRB压边力控制系统,搭建了高强钢TRB盒形件热冲压试验台。通过试验研究了热冲压工艺参数和板料结构形式对高强钢TRB盒形件热冲压成形极限的影响规律,对比实验和数值模拟的成形极限结果验证了数值模拟预测方法的准确性,得出Lemaitre韧性断裂准则可以较准确的预测板料热成形的破裂位置同时其成形极限预测误差在6.35%以内。进一步分析热冲压参数对成形极限的影响原因,得到了高强钢TRB盒形件热冲压的合理工艺参数。
[Abstract]:With the light weight of automobile, the requirement of safety and anti-collision performance is more and more high, the hot stamping forming is used to apply Tailor Rolled Blanksn TRB to the production technology of automobile parts and components. According to the different load capacity requirements of different parts, the components can be used to realize automotive lightweight from the angle of material and structure. However, the thickness of TRB is non-uniform, and the defects such as fracture and wrinkle of the parts in hot stamping process are obvious, so it is very important to study the forming limit of hot stamping of high strength steel TRB. The study on the forming limit of box-shaped parts is of general significance for the study of the forming limit of other complex automobile panels. Based on the thermal tensile stress-strain curve of B1500HS, the constitutive relation model of TRB with temperature, strain rate and thickness is established. Based on continuous damage mechanics and meso-damage mechanics, the Lemaitre and Rice-Tracey ductile fracture criteria for hot forming of high strength steel B1500HS TRB are derived. The material parameters in the ductile fracture criterion are obtained by means of numerical simulation and test. Numerical simulation of hot stamping forming of TRB box of high strength steel with different thickness difference of TRB plate and length of TRB transition zone was carried out by Abaqus. Based on the ductile fracture criterion, Abaqus is redeveloped, and the numerical simulation results of ductile damage model are embedded in the numerical simulation results to obtain the hot forming limit prediction value of TRB box parts of high strength steel under different hot stamping conditions. The test die and TRB blank holding force control system were designed, and the hot stamping test bench for TRB box parts of high strength steel was built. The influence of hot stamping process parameters and sheet metal structure on the forming limit of TRB box parts of high strength steel is studied through experiments. The accuracy of numerical simulation prediction method is verified by comparing the forming limit results of experiment and numerical simulation. It is concluded that the Lemaitre ductile fracture criterion can accurately predict the fracture position of sheet metal hot forming and the prediction error of forming limit is less than 6.35%. The influence of hot stamping parameters on forming limit is further analyzed and the reasonable process parameters of hot stamping for TRB box parts of high strength steel are obtained.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG306

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