Crashworthiness of graded lattice structure filled thin-walled tubes under multiple impact loadings

Abstract

The objective of this study is to investigate the crashworthiness performances of graded lattice structure filled tubes (GLSFTs) under multiple impact loadings. Different graded body-centered cubic aluminum lattice structures are taken into account in the hybrid tube designs by considering different draft angles and base diameters, and the crashworthiness of those structures are examined by using the validated nonlinear finite element method. The crashworthiness performances of the GLSFTs are also compared with the uniform lattice structure filled tubes (ULSFTs) with the same weights to show the efficiency of GLSFTs by considering several crash worthiness indicators (e.g., initial crush force (ICF), peak crush force (PCF), mean crush force (MCF) and specific energy absorption (SEA)). The results revealed that the graded lattice structure designs enable to obtain variable stiffness throughout the length of hybrid tubes and make possible more folds to be formed without global bending, thus provide significantly better energy absorption performance than their uniform counterparts, especially under oblique loadings. Particularly, the results showed that the GLSFTs can have up to 2 times lower ICF and 3.3 times higher SEA values than that of ULSFTs. The results also revealed that the GLSFTs can absorb up to 146% higher impact energy than the sum of energy absorption of their individual components, and a significant improvement in energy absorption performance of GLSFT can be obtained with appropriate selection of design parameters. Hence, GLSFTs can be recommended as passive protection elements in a broad range of energy absorption applications.