激光增材制造拓扑优化轻量化圆锥构件力学性能研究

Aerospace lightweight structures usually need to have multiple performance requirements such as weight reduction, load-bearing, vibration reduction, and impact resistance simultaneously. However, when the structure reduces weight, it is often accompanied by a decrease in load-bearing and impact resistance performance. The topological optimization design of the conical structure was carried out based on the variable density method, and the integrated forming of the conical lightweight component was realized by using the laser powder bed fusion technology. The influence mechanism of the wall thickness on the mechanical properties of the topologically optimized component under the axial compression test was studied. The test results show that as the wall thickness increases from 1.0 mm to 3.0 mm, the specific energy absorption of the structure first increases and then decreases, and the component with a wall thickness of 2.5 mm has the largest specific energy absorption, which is 11.48 J/g. The stress distribution of the topologically optimized conical structure during the compression process was studied by using the finite element simulation method. The results show that the main reasons for the buckling deformation and fracture of the component are the large in-plane compressive stress. The difference in stress levels between the inner and outer walls leads to the buckling deformation of the structure in different directions. Moreover, with the increase of the wall thickness, the stress concentration at the top of the cone and the decrease in the degree of upper-layer buckling both lead to the inability of the structure to continuously increase energy absorption.

航空航天轻量化结构通常需兼具减重、承载、减振、抗冲击等多种性能要求。但结构在减重的同时往往会伴随着承载、抗冲击性能的降低。基于变密度法对圆锥结构进行了拓扑优化设计,并利用激光粉末床熔融技术实现了圆锥轻量化构件一体化成形,研究了轴向压缩试验下壁厚对拓扑优化构件力学性能的影响机制。试验结果表明,随着壁厚由1.0 mm增至3.0 mm,结构的比吸能先增后减,壁厚2.5 mm的构件比吸能最大,为11.48 J/g。采用有限元模拟方法研究了拓扑优化圆锥结构在压缩过程中的应力分布情况,结果表明,构件发生屈曲变形及断裂的主要原因为较大的面内压应力,内外壁应力水平差异导致了结构发生不同方向的屈曲变形,且随着壁厚的增加,圆锥顶部出现的应力集中及上层屈曲程度的降低均导致结构不能持续增加能量吸收。