轻质5052铝合金薄壁焊接吸能管件轴向压缩大变形力学行为

Study on large deformation mechanical performance of light aluminum alloy 5052 welded energy absorption thin-walled tubes under axial compressing

针对汽车用铝合金结构件的安全设计要求,对不同长度的5052H34铝合金焊接单帽结构进行静态轴向压缩试验和有限元模拟。结果表明,构件的长度对其所能承受的最大载荷影响较小,而焊缝的局部性能对结构的平均载荷影响较大;对构件进行有限元模拟发现,其轴向压缩变形模式及叠缩周期与试验结果基本吻合,但构件的载荷和能量吸收与试验结果相差较大。单帽结构在压缩变形过程中,焊缝发生横向折断和纵向撕裂。其中,纵向撕裂导致结构的承载能力迅速下降,是影响结构整体承载能力的关键因素。

Aimed at the requirement of safety design of aluminum alloy components in automobiles, the static axial compression behaviors of different length of 5052H34 aluminum alloy welded top-hat were investigated. The results show that the length of components has insignificant effect on the peak loading Pmax under axial load, but local property of welding line has great effect on the meaning force. The results of the finite element （FE） simulation have good agreement with the experimental ones about deformation modes and cyclic fold. Due to the inhomogenous mechanical property and welding defects of the welding joint, the load capacity and the energy absorption of numerical analysis have a large difference with the experimental results. During the compression deformation, the welding cracks were observed, including transversal fracture and longitudinal tearing which caused the load of structure decreased rapidly, which was a critical question of overall bearing capacity.