Investigation on the temperature distribution in the shearing zone during sheet metal blanking to improve the quality of blanking simulation with material separation

裂纹的萌生和扩展对剪切切削过程的有限元模拟至关重要。为了模拟剪切切削过程中的断裂行为，引入了几种断裂准则。所有断裂准则都是基于这样的假设：材料的分离是在材料特定的、恒定的损伤值处开始的。然而，试验表明，损坏值实际上并不是一个常数。剪切参数的变化需要对该值进行调整。因此，不能提前对冲裁板料表面进行足够质量的模拟。用实际实验对模拟进行调整是很有必要的。关于板料下料过程中剪切区温升的幅度，文献上存在分歧。许多作者认为下料过程中的温升不显著。相比之下，其他科学家则记录了高达750°C的高温。假设如此高的温度，同时忽略过程视图中的温度是不正确的。由于温度的重要性，在这个项目中，试图测量在落料过程中在落料冲床的切削刃上产生的温度分布。基于以上结果，应将温度影响嵌入到剪切切削过程的有限元模拟和相应的损伤准则中，以实现接近现实的断裂起裂和扩展。

The crack initiation and propagation is of crucial importance for the FE-simulation of shear cutting processes. To model the fracture behavior during the shear cutting process, several fracture criteria were introduced. All fracture criteria are based upon the assumption that the separation of the material is initiated at a material specific and constant damage value. However, examinations have shown that the damage value is not really a matter constant. A variation of shear cutting parameters requires an adjustment of the value. Consequently the blanked sheet metal surface cant be simulated with adequate quality in advance. It is always necessary to adjust the simulation with practical experiments.There is a divergence of opinions regarding the extent of the temperature rise in the shearing zone during sheet metal blanking in literature. Many authors assume that the temperature rise during the blanking process is not significant. In contrast other scientists write about very high temperatures up to 750°C. Assuming such high temperatures and at the same time neglecting the temperature in the process view is incorrect.Due to the importance of the temperature it is attempted to measure the resulting temperature distribution during the blanking process on the cutting edge of the blanking punch in this project. Based on these results, the temperature influence should be embedded in the FE-simulation of shear cutting processes and the corresponding damage criteria to achieve a fracture initiation and propagation close to reality.