一种面向增材制造技术的桁架式支架结构设计方法

摘要

针对卫星结构轻量化设计需求,综合应用拓扑优化方法和增材制造技术在结构设计和加工方面的优势,提出一种面向增材制造的桁架式支架结构设计方法.首先,考虑增材制造加工工艺约束,应用拓扑优化方法在结构可行设计空间中寻找最佳传力路径,以此为基础抽象出相对应的桁架结构;然后,应用尺寸优化方法,设计最优的桁架杆件截面尺寸;最后,综合考虑最优杆件尺寸和结构加工/使用约束,进行几何重构,获得可供增材制造的结构设计方案.将方法应用于某卫星敏感器支架结构设计,得到一种相对传统构型减重35.4%的轻量化设计方案.经详细力学分析验证,在使用与传统构型支架相同材料参数和载荷工况下,新型支架基频提高34.3%,安全裕度提高13.0%,同时动态响应系数降低7.3%,验证了方法在结构设计方面的可行性,为同类结构的轻量化设计提供了有益参考.%In order to satisfy the lightweight requirements of satellite structure,a structural design process which combines the advantage of the topology optimization method in structural design and the advantage of the additive manufacturing in structural manufacture is proposed in this paper.Firstly,the best load path is found in the feasible design spaceusing the topology optimization method with the additive manufacturing constraints in mind.Secondly,a trussed structure is extracted from the optimized results and the cross-sectional dimension of the truss is optimized using the sizing optimization method.Finally,after rebuilding the structure based on the previous analysis results and some essential geometry features,a new additive manufacturing oriented design is obtained.Applying the proposed method to a sensor bracket of a satellite,a lightweight design whose mass is reduced by about 35.4% relative to the original design is achieved.With the same material parameters and load cases as the original design,the detailed mechanical analysis shows that the new design improves the fundamental frequency by 34.3%,increases the margin of safety by 13.0%,and reduces the dynamic response coefficient by 7.3%.The test case verifies the feasibility of the proposed method in structural design and a helpful reference is provided for the lightweight design of the similar structure.