A two scale model for damage mechanisms during machining of carbon fibre reinforced plastics

由于其低密度和由此产生的机械性能，碳纤维增强塑料（CFRP）适用于创新的轻质设计概念。部分非均质以及各向异性的纤维基质结构不仅影响最终的加工结果，而且还影响加工操作期间的不同工件性质，例如纤维失效（FF）、基质失效（MF）、纤维基质失效（FMF）和分层。为了更详细地识别这些复杂的损伤机制，将在研究项目中开发一个双尺度模型。双尺度模型捕获的各种损伤机制FF，MF和FMF的框架内的平均场方法。在不同的应变率和温度下使用合适的测试方法分别确定相应类型的故障所需的机械特性，从而考虑到加工操作期间的真实的应力载荷。分层采用了一种内聚区模型，并根据实验数据进行了验证。随后，在有限元程序Abaqus中实现完整的模型，以实现切削过程的宏观模拟，包括由此产生的损伤。通过真实的加工实例对仿真模型进行了修正和验证。开发的模型提供了一个详细的描述的工作关系在CFK的加工。

Due to their low density and the resulting mechanical properties, carbon fiber reinforced plastics (CFRP) are suitable for innovative lightweight design concepts. The partly heterogeneous as well as anisotropic fiber matrix structure not only influences the resultant processing result but also the different workpiece properties during the machining operation, e.g. fiber failure (FF), matrix failure (MF), fiber matrix failure (FMF) and delamination. In order to identify these complex damage mechanisms in more detail, a two scale model will be developed within the research project. The two-scale model captures the various damage mechanisms FF, MF and FMF within the framework of a mean-field method. The required mechanical characteristics of the respective type of failure are determined separately using suitable test methods at different strain rates and temperatures, thus accounting for the real stress load during the machining operation. A cohesive zone model is used for delamination which is verified based on experimental data. Subsequently, the complete model is implemented in the finite element program Abaqus to enable a macroscopic simulation of the cutting process, including the resulting damage. The simulation model is successively adapted and validated by means of real machining. A detailed description of the working relationships in the machining of CFK is provided by the developed model.