HyTop: Development of a coupled topology optimization method for injection-molded, short fiber-reinforced polymer-metal hybrid composites to support the product engineer in design synthesis

本研究项目的目的是开发一种拓扑优化方法，以优化短纤维增强热塑性塑料(SFT)-金属杂化结构，同时考虑热收缩、注射成型过程中产生的残余应力和局部各向异性材料性能。由于破坏时的最大力对混合结构的设计具有决定性作用，因此在优化设计中应将其最大化。前人的研究表明，金属嵌件的形状对聚合物-金属杂化复合材料的力-位移行为和假定的粘接行为具有决定性作用。因此，要研究的拓扑优化方法应该优化金属刀片的几何形状，并考虑以下几个方面：1)得到的刀片几何形状和2)用SFT分量迭代填充刀片中的空穴。此外，拓扑优化方法在迭代过程中既要考虑金属的材料性质，又要考虑SFT矩阵。为此，在文献中描述的用于模拟热和机械行为的模型将被集成。除了载荷相关的应变和应力外，还应考虑SFT结构中的残余应力。代表所考虑的混合结构的两种材料，钢插件根据材料HC420LA和周围的SFT基质根据具有可变玻璃纤维增强含量20的热塑性聚丙烯来建模，对于SFT-金属混合结构设计的拓扑优化方法的开发可以得出以下子目标：·研究用于拓扑优化的结构模型中SFT-矩阵的力学和热性能的模拟映射的合适的建模方法·研究拓扑优化方法中金属嵌件和SFT-矩阵之间的粘结区的不同建模方法·研究用于拓扑优化的结构模型的自动建立方法，包括用补充材料填充金属嵌件中的缺口·研究不同的方法，以适应基于灵敏度的拓扑优化过程，以优化SFT-金属混合结构的形状·推导设计准则，并将相应的边界条件实施到拓扑优化方法中(例如最小半径、最小空腔尺寸)

The aim of this research project is the development of a topology optimization method for the optimization of short-fiber reinforced thermoplastic (SFT) -metal hybrid structures under consideration of thermally induced shrinkage, resulting residual stresses and local anisotropic material properties from the injection molding process. Since the maximum force in the event of failure is decisive for the design of the hybrid structure, it should be maximized in the optimization. As could be shown in previous studies, the shape of the metal insert is decisive for the force-displacement behavior of the polymer-metal hybrid composite for a given polymer matrix and assumed adhesion behavior. Therefore, the topology optimization method to be investigated should optimize the geometry of the metal insert and consider the following aspects: 1) the resulting geometry of the insert and 2) the filling of the resulting cavities in the insert with the SFT-component iteratively. Furthermore, the topology optimization method should consider the material properties of the metal as well as the SFT-matrix in the iterations. For this purpose, models described in the literature for simulating the thermal and mechanical behavior are to be integrated. In addition to the load-dependent strains and stresses, residual stresses in the SFT structure should also be taken into account. Representing the two materials of the considered hybrid structure, the steel insert is modelled according to the material HC420LA and the surrounding SFT matrix according to the thermoplastic polypropylene with variable glass fiber reinforcement content of 20, 40 and 60 volume-%.The following subgoals can be derived for the development of the topology optimization method for the design of SFT-metal hybrid structures:• Investigation of suitable modelling approaches for the simulative mapping of the mechanical and thermal properties of the SFT-matrix in the structural model for topology optimization• Investigation of different modeling approaches of the cohesive zone between metal insert and SFT-matrix in the topology optimization method• Investigate a method for automatically building the structural model for topology optimization, including filling the gaps in the metal insert with the complementary material• Investigation of different approaches for the adaptation of the sensitivity-based topology optimization process for the optimization of the SFT-metal hybrid structures in shape finding• Derivation of design guidlines and implementation of corresponding boundary conditions into the topology optimization method (e.g. minimum radii, minimum cavity size)