基于增材制造各向异性的强度约束拓扑优化

Strength-constrainted Topology Optimization Based on Additive Manufacturing Anisotropy

增材制造工艺的特殊性导致制造结构展现出各方向不同的力学性能,为满足其所带来的更加严苛的结构强度设计需求,提出了一种基于双向渐进结构优化法的各向异性强度约束拓扑优化策略。推导了描述增材结构强度的各向异性Tsai-Hill失效系数,通过权重因子构建了包含失效系数约束的目标函数。详细求解了优化灵敏度公式,并采用敏度归一化等数值方法稳定优化历程。典型算例表明,所提方法可有效抑制高失效风险区域以保证结构强度,且在材料各向异性强度假设下可获得更优于von-Mesis应力相关设计的结果。此外,优化结果高度依赖于各向异性程度与材料堆叠角度参数的变化,因此合理的调整将有助于优化结构性能。

The particularity of additive manufacturing processes leds to the fact that the manufacturing structure exhibited anisotropic mechanics properties. In order to meet the more stringent structural strength design requirements, atopology optimization strategy considering anisotropic strength constraints was proposed based on bi-directional evolutionary structural optimization. The anisotropic Tsai-Hill failure coefficient evaluating additive structural strength was derived, and an objective function containing the constraint of failure coefficient was established by the scale factor. The sensitivity numbers were analyzed in detail, moreover, numerical methods such as sensitivity normalization were used to stabilize the optimization processes. It shows that the proposed method effectively suppresses the high failure risk area, thus, ensures the structural strength, and may obtain better results than that of von-Mesis stress-dependent design under material anisotropic strength assumption. In addition, the optimization results are deeply rely on the variation of anisotropy and the material stacking angle parameters, therefore reasonable tuning will help to optimize structural properties.