Improvement of Crashworthiness Indicators with a New Idea in the Design of the Multi-Cell Hexagonal Tube under Dynamic Axial Load

Abstract

Multi-cell hexagonal tubes have been applied in a wide range of industries. The present study investigates strengthening a single regular hexagonal tube under a dynamic axial load with three different geometrical shapes. The results are then compared with crashworthiness indicators from the finite element code LS-DYNA using the simple additive weighting method, and the appropriate section of a multi-cell hexagonal tube under dynamic axial load is selected. An idea is further presented by assuming the thicknesses variable for certain parts of the selected section to improve crashworthiness criteria. Combinations with different variable thicknesses in defined thickness intervals are made into a lattice. Numerical tests are performed based on the lattice nodes using LS-DYNA. The regression models for crashworthiness indicators are created using the Minitab software and optimized to find optimum combinations of thicknesses. The optimization results are tested again by LS-DYNA, and the appropriate answers are determined. The comparison of the results of this method with those of optimization with constant thicknesses demonstrates improvement in the crashworthiness indicators.

Keywords

• multi-cell hexagonal tube
• crashworthiness criteria
• regression model
• optimization
• specific energy absorption
• crashing force efficiency