Crushing analysis of foam-filled single and bitubal polygonal thin-walled tubes

•A modeling technique coupling FEM and element free Galerkin method is adopted.•The multicriteria decision making process is adopted.•The crashworthiness of foam-filled single and bitubal polygonal columns is compared.•Multiobjective optimization design for foam-filled circular bitubal tube is conducted.•The foam-filled circular bitubal column has outstanding crashworthiness.

Foam-filled thin-walled structures have drawn considerable attention and been widely applied in automotive and aerospace industries for their significant advantages in high energy absorption and light weight. This paper aims to compare the energy absorption characteristics of foam-filled single and bitubal polygonal tubes with different cross-sectional configurations under different axial crushing load conditions. The coupled finite element method (FEM) and element free Galerkin method (EFGM) are applied in modeling the foam-filled tubes for their interaction associated with large deformation, failure and damage. By the complex proportional assessment (COPRAS) technique – the multicriteria decision-making method, the comparisons of energy absorption characteristics of the considered single and bitubal polygonal tubes are conducted herein, respectively. The results show that the foam-filled circular bitubal column has outstanding energy absorption characteristics under all the conditions considered. It is found that the mean crushing force and energy absorbed generally increase with the increase in the edge number of foam-filled bitubal columns. The multiobjective optimization of foam-filled circular bitubal tube is finally conducted by using Non-dominated Sorting Genetic Algorithm (NSGA-II) for the maximization of specific energy absorption (SEA) and the minimization of peak crushing force (PCF).