Hybrid flat-clinching of renewable raw materials

该项目的目的是对金属和可再生原材料通过塑性变形连接的平铆进行实验和数值研究。为了首次对硬木与金属的连接进行数值研究，有必要对现有的软木材料模型进行改进。基于连接金属和硬木与平铆的连接机制的知识增加的数值过程模拟的努力，这最终应导致可重复的连接过程的指导方针。有限元模型的标定将在实验结果的基础上实现。此外，平铆纤维板（平铆）的数值模拟是该项目的另一个重要方面。纤维板的各向同性结构与纤维增强塑料相当。因此，将检查现有纤维增强塑料材料模型对纤维板建模的适用性。通过拉伸和压缩试验，实现基体材料（粘结增强剂）和增强材料（木纤维）性能的匹配。为了在SPP中做出进一步的实质性贡献，将测试无网格伽辽金法（EFGM）作为平板铆接有限元模拟的替代方法。由于不必要的重新网格划分，EFGM特别适用于具有高塑性应变的工艺，如平铆。这导致计算时间的减少和模拟精度的提高。由于缺少使用EFGM进行平铆模拟的专门知识，因此将在项目中实现常规铆合的调查。由此产生的知识增长将总结在指导方针中，该指导方针将向SPP 1640的成员开放。此外，这些知识将用于项目内的平铆模拟。

The aim of the project is the experimental and numerical investigation of flat-clinching of metal and renewable raw materials due to joining by plastic deformation. For the numerical investigations of joining hardwood and metal for the first time, it is necessary to improve an existing material model for softwood. Based on the numerical process simulation for joining metal and hardwood with flat-clinching an increased knowledge of the joining mechanisms is striven, which should finally lead to guidelines for a reproducible joining process. The calibration of the FEM models will be realized on the basis of the experimental results. Furthermore, the numerical modeling of flat-clinching fiberboard (MDF) is another essential aspect of the project. The isotropic structure of fiberboard is comparable with fiber-reinforced plastics. Due to that, the applicability of existing material models for fiber-reinforced plastics for modeling fiberboard will be checked. The adaptation of the properties of the matrix material (adhesion promoter for MDF) and the reinforcements (wood fiber for MDF) will be realized by tensile and compression tests.In order to make a further substantial contribution within the SPP, the use of the Element-Free Galerkin method (EFGM) will be tested as an alternative for the FE simulation of flat-clinching. The EFGM is especially beneficial for processes with high plastic strains like flat-clinching, due to the unnecessary remeshing. This leads to a reduction of computation time and an improvement the of the simulation accuracy. Due to the missing know-how for the simulation of flat-clinching with EFGM investigations for the conventional clinching will be realized within the project. The resulting increase in knowledge will be summarized in guidelines, which will be open to the members of the SPP 1640. Furthermore, the knowledge will be used for the simulation of flat-clinching within the project.