泡沫铝填充双层金属点阵结构增强效应及吸能特性

Enhancement effect and energy absorption of double-layer metallic lattice structure filled with aluminum foam

摘要:

以泡沫铝和金属点阵为代表的金属多孔结构由于具有轻质、高强（比强度、比刚度、能量吸收率）及多功能可设计性等特点，在轻质结构承载领域具有广泛的应用潜力。但泡沫铝的低强度和金属点阵的芯体屈曲很大程度上限制了其工程应用。本文通过激光焊接获得三种不同几何构型的双层金属点阵结构，再将闭孔泡沫铝切割后填充到其孔隙当中获得一种新型泡沫铝填充双层金属点阵结构。采用实验和有限元模拟的方法研究其准静态面外压缩载荷作用下的承载能力、吸能特性及机理、变形破坏模式等行为。结果表明，泡沫铝的填充能够有效改变空心点阵结构的后屈曲行为，提高点阵芯体单元的屈曲稳定性，具有明显的耦合增强效应，表现在承载及能量吸收效率的大幅提升，可达到对应空心结构的十倍以上。

Abstract:

The porous metal structure represented by aluminum foam and metal lattice has wide application potential in the field of lightweight structural load due to its light weight, high strength (specific strength, specific stiffness, energy absorption rate) and multifunctional design. However, the low strength of foamed aluminum and the buckling failure of metal lattices have largely limited their engineering applications. In this paper, three kinds of double-layer metal lattice structures with different geometries are obtained by laser welding, and then a closed-cell aluminum foam is filled into the pores to obtain a new foam aluminum-filled double-layer lattice structure. The experimental and finite element simulation methods are used to study the bearing capacity, energy absorption characteristics, mechanism and deformation failure mode under quasi-static surface compression load. The results show that the filling of aluminum foam can effectively change the post-buckling behavior of the hollow lattice structure, improve the buckling stability of the lattice core unit, and have obvious coupling enhancement effect, which is manifested in the significant increase of bearing capacity and energy absorption efficiency.