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

该项目的目的是开发一种用于确定高应变率过程的材料和失效特性的方法。因此，与现有技术相比，具有高成形速度的生产过程的数值分析和设计可以得到显著改善，并且可以对在工业生产中利用已知的过程特有的优点做出决定性贡献。在第一个供资期间，实现并研究了一种数值和实验相结合的方法。实验结果表明，所建立的实验装置和参数反演系统可用于确定成形速度高达5 × 104/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，这种效应在准静态加载下不会发生。现在将扩展该方法，以考虑绝热加热的影响和相关的屈服应力的局部降低。特别是，必须澄清在何种程度上差异可归因于试验期间材料的不同加热。为此目的，一个相结合的数值和实验的方法是追求。详细地说，材料模型在模拟中通过温度依赖性进行扩展，然后用于逆确定纯应变率依赖的材料参数。这样就可以将成形速度和温度对材料行为的叠加和相反作用的影响分离开来，从而全面验证确定材料参数的扩展方法。最初，IWU将在液压驱动的高速试验机上进行不同温度下的试验。在此基础上，通过不同应力状态的技术试验进行了进一步验证。FF考虑高速深冲工艺，而IWU则专注于高速切割。最后，在综合步骤中对数据进行合并，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.