Material- and failure characteristics for high-speed forming and cutting

该项目的目的是开发一种确定高应变率工艺的材料和失效特征的方法。因此，与现有技术相比，可以显著改进具有高成形速度的生产工艺的数值分析和设计，并且可以为在工业生产中利用已知工艺特有的优势做出决定性的贡献。在第一个资助期，实现和研究了数值和实验相结合的方法。实验证明，所开发的实验装置和逆参数识别系统可用于确定成形速度高达5∙10~4/S的材料参数。材料参数在不同的应力状态下表现出显著的差异，这种影响在准静态加载下不会发生。现在将扩展该方法，以考虑绝热加热和相关的局部屈服应力降低的影响。特别是，必须弄清楚在多大程度上可以将差异归因于试验期间材料的不同加热。为此，我们采用了数值计算和实验相结合的方法。具体地，在模拟中将材料模型扩展为温度依赖关系，然后用于反确定纯应变率相关的材料参数。这使得能够分离成形速度和温度对材料性能的叠加和相反作用的影响。确定材料参数的扩展方法将得到全面验证。最初，IWU将在液压驱动的高速试验机上进行不同温度下的测试。在此基础上，利用不同应力状态的工艺试验进行了进一步的验证。FF考虑的是高速拉深工艺，而IWU则将重点放在高速切割上。最后，在合成步骤中合并数据，并以可作为开放数据提供的方式进行准备。

The aim of the project is to develop a method for determining material and failure characteristics for processes with high strain rate. Thus, the numerical analysis and design of production processes with high forming speeds can be significantly improved compared to the state of the art and a decisive contribution can be made to the utilization of known process-specific advantages in industrial production. In the first funding period, a combined numerical and experimental approach was realized and researched. It was proven that the developed experimental setups and an inverse parameter identification system can be used to determine material parameters for forming speeds of up to 5∙104/s. The material parameters show significant differences for different stress states, an effect that does not occur under quasi-static loading.The approach will now be extended in order to consider the influence of adiabatic heating and the associated local reduction in yield stress. In particular, it must be clarified to what extent differences can be attributed to different heating of the material during the test. For this purpose, a combined numerical and experimental approach is pursued. In detail, the material model is extended in the simulation by a temperature dependence and then used for the inverse determination of the purely strain rate dependent material parameters. This enables a separation of the superimposed and oppositely acting influences of forming speed and temperature on the material behavior.The extended method for determining material parameters will be comprehensively validated. Initially, IWU will perform tests at different temperatures at on a hydraulically driven high-speed testing machine. Based on this, further verification is done using technological tests with different stress states. FF considers a high-speed deep-drawing process, while IWU puts the focus on high-speed cutting. Finally, the data is consolidated in a synthesis step and prepared in such a way that it can be provided as open data.