Efficient optimization of topology and raster angle has shown unprecedented enhancements in the mechanical properties of 3D printed thermoplastic polymers. Topology optimization helps reduce the waste of raw material in the fabrication of 3D printed parts, thus decreasing production costs associated with manufacturing lighter structures. Fiber orientation plays an important role in increasing the stiffness of a structure. This paper develops and tests a new method for handling stress constraints in topology and fiber orientation optimization of 3D printed orthotropic structures. The stress constraints are coupled with an objective function that maximizes stiffness. This is accomplished by using the modified solid isotropic material with penalization method with the method of moving asymptotes as the optimizer. Each element has a fictitious density and an angle as the main design variables. To reduce the number of stress constraints and thus the computational cost, a new clustering strategy is employed in which the highest stresses in the principal material coordinates are grouped separately into two clusters using an adjusted $P$-norm. A detailed description of the formulation and sensitivity analysis is discussed. While we present an analysis of 2D structures in the numerical examples section, the method can also be used for 3D structures, as the formulation is generic. Our results show that this method can produce efficient structures suitable for 3D printing while avoiding stress concentrations.
翻译:3D印刷的热塑性聚合物的机械性能出现了前所未有的改善; 地形优化有助于减少制造3D印刷部件过程中原材料的浪费,从而降低与制造轻质结构有关的生产成本; 纤维定向在提高结构的僵硬度方面发挥着重要作用; 本文制定并试验了一种新的方法,用以处理3D印刷的圆形结构的地形和纤维定向优化中的压力限制; 压力制约与一个能最大限度地提高僵硬度的客观功能相配合; 通过使用经过修改的固态异地材料和惩罚方法,将微粒作为优化器移动,从而减少了原材料的浪费; 地形优化有助于减少3D印刷的印刷部件的密度和角作为主要设计变量。 为了减少压力限制的数量,从而降低计算成本,采用了一种新的组合战略,将主要材料坐标中的最大压力分别分组成两个组群,使用经调整的$P$-norm; 详细描述配制和敏感性分析。 我们在数字示例部分对2D结构进行了分析,同时将2D结构进行模拟分析,同时将这一方法用于避免通用压力的结构。