基于动力显式算法的热成形数值模拟预测

考虑金属热处理相变动力学模型,建立了适用于高强度钢板热成形的热、力、相变多场耦合本构方程。基于大变形动力显式有限元算法及上述多场耦合本构方程,建立了热成形动力显式有限元方程。并将板料相变潜热释放引入到热成形温度场分析过程中。在自主开发的商业化金属成形CAE软件KMAS(King Mesh Analysis System)基础上开发了热成形动力显式分析模块,可用于预测热成形过程中零件的厚度变化、温度变化、微观组织各相的体积分数以及硬度分布。随后采用该模块对一款汽车B柱的热成形过程及最终力学性能进行数值模拟预测,并与试验结果进行对比,对比的一致性证明了所建立的多场耦合本构方程及KMAS热成形动力显式分析模块的正确性。

NUMERICAL SIMULATION ON HOT FORMING BASED ON DYNAMIC EXPLICIT ALGORITHM

Based on the phase transformation kinetics models for the heat treatment of a metal sheet, the thermo-elastic-plastic constitutive equation was established, which is coupled with the mechanical strain, thermal strain, phase transformation strain and transformation induced plasticity, and suitable for hot-forming of high strength steel. The finite element equations of hot-forming were established based on dynamic explicit algorithm and the constitutive equation accounting for the multi-physical coupling. And the transformation latent heat release of blanks was introduced into the analysis of a temperature field during hot-forming. The KMAS (King Mesh Analysis System) hot-forming module was developed and can be used to predict the thickness, temperature, volume fraction of each phase and the hardness distribution of parts during a hot-forming process. Subsequently, the hot-forming process and final properties of an automotive B-pillar simulated by the KMAS were compared to the experiment. A good agreement between numerical simulation and the experiment results is shown, which confirms the validity of the constitutive equation and the hot-forming module.