Hybrid flat-clinching of renewable raw materials

该项目的目的是对金属和可再生原材料由于塑性变形连接而产生的扁平紧固进行实验和数值研究。对于首次进行硬木与金属连接的数值研究，有必要对现有的软木材料模型进行改进。基于金属与硬木平接连接的数值模拟，力求增加对连接机理的认识，最终指导可重复的连接过程。有限元模型的标定将以实验结果为基础。此外，平压纤维板(MDF)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，将检查现有的纤维增强塑料材料模型对纤维板建模的适用性。将通过拉伸和压缩试验实现基质材料(中密度纤维板的粘合促进剂)和增强材料(中密度纤维板的木纤维)的性能匹配。为了在SPP中做出进一步的实质性贡献，将试验使用无网格伽辽金方法(EFGM)作为平面连接的有限元模拟的替代方案。由于不必要的重新啮合，EFGM特别适用于具有高塑性应变的工艺，如扁平紧固。从而减少了计算时间，提高了仿真精度。由于缺少EFGM模拟扁平扣件的技术诀窍，将在该项目内实现对常规扣件的研究。由此产生的知识增长将在指导方针中加以总结，该指导方针将向战略规划编制委员会1640成员开放。此外，该知识还将用于项目内的压扁模拟。

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.