内部缺陷对闭孔泡沫铝压缩性能影响的有限元分析

Finite element analysis for the influence of the closed-cell aluminum foams compression performance with internal defects

泡沫铝是由铝或铝合金骨架及大量气泡构成的新型金属材料,其压缩性能在很大程度上受其内部缺陷及结构参数的影响.本文通过构建闭孔泡沫铝三维模型并应用Deform-3D软件对其准静态压缩变形过程进行数值模拟计算,讨论了结构参数及内部缺陷对其压缩性能的影响.实验结果显示:在准静态压缩过程中,随着孔隙率的增大闭孔泡沫铝的屈服平台应力逐渐减小;而在孔隙率相同的条件下,其平台应力随孔径的增大而减小;裂纹、大孔洞等缺陷会在一定程度上降低泡沫铝的力学性能,且应力一般集中在缺陷处.闭孔泡沫铝压缩过程中的变形主要以平行于加载方向的孔壁压缩变形为主,在胞壁的交界处应力相对集中,随着载荷的增加,这些交界处会发生塑性屈服或者断裂失效.

Aluminum foam is a new metal material made of aluminum or aluminum alloy frame with a large amounts of bubbles. Its compression performance is largely influenced by internal defects and structural parameters. The 3D models of closed-cell aluminum foam was built and simulated by using the software of Deform-3D discussing the effects of the internal defects and structural parameters on the compression performance. The results show that in the quasi-static compression process, the yield strength of closed-cell aluminum foam decreases with the increase of porosity; and with the same porosity, the platform stress of closed-cell aluminum foams decreases with pore size increasing; cracks, holes and other defects, to some extent, reduce the mechanical properties of aluminum foam, especially the stress generally focused on the defect. The main deformation of closed-cell aluminum foam during compression loading direction is parallel to the walls of the hole compression-based, at the junction of the stress in the cell wall is relatively concentrated with the load increasing, which occurs at the junction of plastic yielding or fracture failure.