Crashworthiness analysis and multiobjective optimization for circular tubes with functionally graded thickness under multiple loading angles

Abstract

In this article, the nonlinear finite-element analysis software LS-DYNA is used to study the crashworthiness of functionally graded thickness circular tubes under multiple loading angles (0°, 10°, 20°, 30°, and 40°). The specific energy absorption (SEA) and maximum crashing force ([Formula: see text]) are used as evaluation indices with which to analyze the effect of the length-to-diameter ratio and thickness gradient index P on the crashworthiness characteristics of functionally graded thickness circular tubes. Taking the length-to-diameter ratio and thickness gradient as design variables, the full factorial experiment was designed. A surrogate model of the integrated specific energy absorption ([Formula: see text]) and maximum crashing force ([Formula: see text]) when the impact angle is 0° was constructed using the response surface method; the nondominated sorting genetic algorithm II was used to optimize the surrogate model, and the Pareto-front solution set was obtained. The results show that the thickness gradient index and the length-to-diameter ratio have a greater influence on the crashworthiness characteristics of functionally graded thickness circular tubes under oblique impact load, and the appropriate geometric parameters can improve the crashworthiness characteristics of functionally graded thickness circular tubes.