基于固有应变法的卫星支架结构SLM变形趋势仿真

Simulation of SLM Deformation Trend of Satellite Bracket Structure Based on Intrinsic Strain Method

选区激光熔化技术为航天器的设计和制造提供了更大的自由度,在成形复杂结构方面具有明显优势。然而,SLM过程中需要添加支撑以保证零件成形,由于金属材料在热力学性能方面与非金属材料有较大差别,成形过程更易变形,因此SLM工艺对材料的热导率、抗变形能力更加敏感。由于缺乏增材制造工艺的标准与规范,现阶段粉末床增材制造仍然沿用传统的“试错”模式,SLM成形带有支撑结构的复杂零件时仍有变形和开裂问题,造成了材料和机器时间的浪费。针对一种拓扑优化结构,在宏观层面上模拟4种不同支撑方案的SLM工艺过程,预测4种方案的应力和变形情况,探索最佳成形方案,最后对比实际打印结果和仿真结果,从而分析仿真模型的精确性和误差来源,为SLM工艺方案的制定提供参考。

Selective laser melting(SLM)technology provided greater freedom for the design and manufacture of spacecraft and it had significant advantages in forming complex structures.However,support structure needed to be added to ensure the forming of the part during SLM.Because the metallic material had great differences in thermal and mechanical properties from non-metallic material,it was more prone to deformation during the forming process,so it was more sensitive for thermal conductivity and deformation resistance of materials.Due to the lack of standards for additive manufacturing,the mode of current trial and error for powder bed additive manufacturing was still used.SLM process still had the problem of deformation and cracking when forming complex parts with supporting structures,which resulted in waste of materials and machines time.For a topology optimization structure,the SLM process of four different placement directions and support schemes was considered.To explore optimal forming scheme,stress and deformation of the four modes were predicted and the actual printing results and simulation were compared.The results were used to analyze the accuracy and error sources of the model so that it can provide a reference for the development of the SLM process plan.