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

裂纹的萌生和扩展是剪切过程有限元模拟的关键。为了模拟剪切过程中的断裂行为，引入了几种断裂准则。所有的断裂准则都是基于这样的假设，即材料的分离是在材料特定且恒定的损伤值开始的。然而，检查表明，损害价值并不是一个真正的常量。剪切切割参数的变化需要调整该值。因此，不能预先模拟出具有足够质量的板料冲裁表面。板料冲裁过程中剪切区温升的大小，在文献中一直存在着分歧。许多作者认为冲裁过程中的温升并不显著。相反，其他科学家写到了高达750°C的非常高的温度。假设这么高的温度，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，试图测量落料过程中在落料冲床刃口上产生的温度分布。基于这些结果，在剪切切割过程的有限元模拟和相应的损伤准则中应考虑温度的影响，以实现更接近实际的裂纹萌生和扩展。

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.