选区激光熔化成形不同偏移率拱形点阵结构力学性能

Mechanical properties of arch lattice structures with different offset ratios by selective laser melting

为研究不同偏移率对力学性能的影响,利用选区激光熔化技术成形12个不同偏移率的Al Si10Mg拱形点阵试样,通过准静态压缩试验分析偏移率对点阵抗压强度、弹性模量的影响,结合有限元仿真和压缩试验,分析不同偏移率拱形点阵应力集中的变化对点阵失效形式的影响.结果表明,拱形点阵的偏移率在20%时抗压强度和弹性模量达到最大值,相对未偏移点阵的抗压强度和弹性模量分别提升了49%和28%.随着偏移率的增加点阵的应力集中先由结点向结点两端杆件转移,点阵的失效形式由逐层坍塌变为剪切断裂,此时偏移率的增加对点阵的结点有强化作用,后又出现向结点处集中的趋势,并且结点中心应力逐渐下降,点阵的失效形式由剪切断裂变为剪切断裂伴随结点崩碎,此时偏移率的增加削弱了点阵的结点强度.

In order to study the effects of different offset ratios on the mechanical properties of the arch lattice,12 AlSi10Mg arch lattice samples with different offset ratios were formed by selective laser melting technology.Quasi-static compression tests were conducted to analyze the effects of offset ratios on the compressive strength and elastic modulus of the lattice.Combined with finite element simulation and compression test,the influence of the change of stress concentration on the failure mode of arch lattice with different offset ratios was analyzed.The results show that the compressive strength and elastic modulus of the arch lattice reach the maximum value when the offset ratio is 20%,and the compressive strength and elastic modulus of the arch lattice are increased by 49%and 28%,respectively.With the increase of the offset ratios,the stress concentration of the lattice first diffuses from the node to the member at both ends of the node,and the failure form of the lattice changes from layer by layer collapse to shear fracture.At this time,the increase of the offset ratios has a strengthening effect on the node of the lattice,and then there is a trend of concentration to the node,and the central stress of the node gradually decreases,and the failure form of the lattice changes from shear fracture to shear fracture with the collapse of the node.At this time,the increase of the offset ratios weakens the node strength of the lattice.