基于渐进演化策略的增材制造自支撑结构拓扑优化算法

拓扑优化和增材制造分别是先进的结构设计技术和制造技术,将拓扑优化与增材制造融合能产生显著的协同效益.增材制造存在一些独特的制造约束,研究考虑结构自支撑约束的拓扑优化算法,可以降低材料和时间成本.基于SIMP方法框架,建立显式约束函数模型表征结构的自支撑特性,并发展了相应的拓扑优化流程,通过结构渐进演化实现自支撑.研究了相应的灵敏度分析方法,可实现并行计算.提出一个指向性灵敏度过滤算子促进支撑结构演化.采用3个数值算例进行分析,验证了指向性灵敏度过滤的有效性,所有拓扑优化结果均实现了结构自支撑.与典型方法相比,优化结果的可制造性更好.

Topology optimization of self-supporting structure for additive manufacturing by gradual evolution strategy

Topology optimization and additive manufacturing are respectively the advanced structural design and manufacturing technologies.The combination of topology optimization and additive manufacturing can bring significant synergetic benefits.The additive manufacturing processes have certain manufacturing constraints,and this paper focuses on the topology optimization algorithm considering the self-supporting constraint,which can reduce the material and time costs.Based on the SIMP framework,an explicit constraint function is devised to quantify the self-supporting characteristic.The optimization process considering the self-supporting constraint is then developed,in which the optimization realizes self-support through gradual structural evolution.A corresponding sensitivity analysis method is proposed,which can be used in parallel computation.A directional sensitivity filter is proposed to promote the evolution of supporting structures.Three numerical examples are adopted to verify the proposed method, and the results show that the proposed directional sensitivity filter is effective,and all results realize self-support.Besides,the results indicate better manufacturability compared with the typical methods considering self-supporting constraint.