考虑激光粉末床熔融成形铺粉过程的自支撑拓扑优化算法  

Self-Supporting Topological-Optimization Algorithm Considering Powder-Recoating Process in Laser Powder-Bed Fusion

作　　者：张凯飞 陈奇 鄢然 马帅 向召伟 袁博 Zhang Kaifei;Chen Qi;Yan Ran;Ma Shuai;Xiang Zhaowei;Yuan Bo(College of Mechanical Engineering,Chongqing University of Technology,Chongqing 400054,China)

机构地区：[1]重庆理工大学机械工程学院,重庆400054

出　　处：《中国激光》2024年第20期253-260,共8页Chinese Journal of Lasers

基　　金：国家自然科学基金(52305247,52305148);重庆市教育委员会科学技术研究项目(KJQN202201112);重庆市自然科学基金(cstc2020jcyj-msxmX0248,cstc2021jcyj-msxmX0143)。

摘　　要：悬角约束是面向增材制造的零件拓扑优化设计中考虑最多的一种约束,且以45°等值约束为主,其虽然能够实现零件自支撑设计且具有较好的通用性,但与具体的增材制造工艺及装备性能脱节,在一定程度上限制了拓扑优化设计的应用潜力。本课题组结合激光粉末床熔融(LPBF)成形工艺及装备特点,提出了一种考虑铺粉过程的自支撑拓扑优化设计方法。该方法基于变值悬角约束改进现有变密度拓扑优化方法,扩大了寻优空间,从而提高了拓扑优化的性能。二维与三维算例证明了该方法的有效性:在相同的约束和边界条件下,是否添加悬角约束与拓扑结构刚度变化之间没有明显的规律。与基于等值悬角约束的自支撑拓扑优化方法相比,基于变值悬角约束的自支撑拓扑优化方法获得的拓扑结构的刚度明显提升。Objective Additive manufacturing(AM)enables the fabrication of extremely complex structures,which can reveal the full potential of topological optimization(TO).However,it presents certain limitations that should be considered in TO.A typical example is that an overhang structure cannot be easily formed in AM without incorporating additional support structures.Therefore,many selfsupporting TO algorithms have been proposed to avoid generating components with overhanging structures by considering the incline angle constraint(IAC).The IAC is usually set to a constant value,typically 45°,at all polar angles.Although it can realize the selfsupporting design of components and features high versatility,the effects of the AM process and equipment performance on the IAC are typically disregarded,thus resulting in a self-supporting TO algorithm with subpar performance.To fully understand the active role of TO,a self-supporting TO design method that considers the powder-recoating process is proposed based on the characteristics of the laser powder-bed fusion(LPBF)process and equipment.Methods In this study,based on the authors’previous study where the changing law of the IAC due to the powder-recoating process in LPBF was investigated,a new self-supporting TO design method is proposed.First,the method for determining the IAC was reviewed;notably,the IAC is not constant but changes with the polar angle.Subsequently,a variable-value IAC was proposed after a mathematical formula for the change in the IAC with the polar angle was derived.Second,a variable-value IAC was integrated into an improved solid isotropic material with penalization(SIMP)TO algorithm in the form of a filter using the min–max operator.Third,the proposed algorithm was validated using two-dimensional(2D)and three-dimensional(3D)MBB beam examples and supplemented with additional examples using an L-beam,a compression structure,and a cantilever beam to generalize the results.Finally,a set of 3D TO MBB beams was selected to be formed via LPBF to further val

关 键 词：激光技术 激光粉末床熔融 拓扑优化 悬角约束 铺粉过程 自支撑 

分 类 号：TH122[机械工程—机械设计及理论]