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针对电加热拉弯成形工艺,建立了电热拉弯过程顺序耦合的数值模拟方法,实现了电热转台式拉弯成形过程的多工序、多场耦合数值模拟。并选用动力显式热-力耦合分析算法,基于J-C断裂准则,建立了电热拉弯成形极限与断裂预测的三维实体模型。通过Ti-6Al-4V钛合金挤压T型材电热拉弯成形试验与仿真预测结果比较发现:电热拉弯成形过程中,材料的失效主要发生在预拉伸和补拉伸阶段,失效原因为拉伸力过大;电热拉弯成形极限的主要影响因素包括加热温度或电流密度、预拉力、补拉伸过程温度或冷却时间和补拉力;预拉伸和补拉伸极限应力的预测相对误差分别为19.7%和19.1%,验证了模型的有效性。
Aiming at the electric heating bending forming process, a numerical simulation method of sequential coupling of electric heating and bending process was established, which realized the multi-process and multi-field coupled numerical simulation of electric rotary table bending and forming process. Based on the J-C fracture criterion, a three-dimensional solid model of forming limit and fracture prediction of electrothermal bending was established by using dynamic explicit thermo-mechanical coupling analysis. The results of the comparison between the electric tension forming test and the simulation prediction of T-shaped extruded Ti-6Al-4V titanium alloy show that the failure of the material mainly occurs in the pre-stretching and the supplementary stretching stages, Tensile strength is too large; Electric tension forming the main factors that affect the forming limit, including heating temperature or current density, pre-tension, make-up process temperature or cooling time and make up; prestress and make up tensile ultimate stress relative error respectively 19.7% and 19.1%, respectively, which validated the validity of the model.