Crashworthiness and optimization for foam-filled multi-layer composite lattice structures

Foam materials have been widely used to fill composite lattice structures to improve energy absorption and mechanical properties. In this paper, several novel types of foam-filled multi-layer composite lattice structures (FMCLSs) were proposed, and their crashworthiness analysis and multi-objective optimization were conducted. The finite element method was adopted to investigate the compressive behavior of the FMCLSs. Quasi-static compression experiments were performed on the FMCLSs manufactured using a vacuum infusion molding process (VIMP) to verify the accuracy of the finite element models. Furthermore, validated finite element models were employed to conduct parametric studies on the FMCLSs. For the FMCLS with double-layer dislocation cells or trapezoidal cells, the crush force efficiency (CFE) achieved average values of 44.86 % or 50.47 %, respectively, which were higher than those of the other types of FMCLSs. To obtain the optimal designs of the FMCLSs, metamodels and the MOPSO algorithm were utilized, with the specific energy absorption (SEA) and peak crushing force (PCF) selected as the two objectives. The optimization results demonstrated that the FMCLSs with double-layer dislocation cells and hexagonal cells had better crashworthiness than the other types of FMCLSs and could serve as effective energy absorbers. Meanwhile, with the PCF constrained to a value greater than 82 kN, the FMCLS with hexagonal cells exhibited the best crashworthiness; whereas, when the PCF was less than 82 kN, the FMCLS with double-layer dislocation cells performed the best. Additionally, the equivalent compressive modulus and compressive strength of the FMCLSs were predicted using a rule of mixtures.