Theoretical prediction and crashworthiness optimization of multi-cell square tubes under oblique impact loading

Multi-cell square tubes under dynamic oblique impact loading were studied in our work. The theoretical predictions of mean crushing force, mean horizontal force, and mean bending moment were proposed by dividing the profile into basic angle elements based on a Simplified Super Folding Element (SSFE) theory. The formulas of an oblique impacting coefficient (λ) with a load angle of 15° were proposed based on the geometric parameters, the inertia effect and the oblique loading angle by taking the effect of oblique loading and dynamic crushing into account for aluminum alloy tubes. A new method was proposed to find out a “knee point” from Pareto set with maximizing the reflex angle. The optimal configurations of multi-cell tubes were analyzed under axial and more than one oblique impact loadings. The results showed that the FE numerical results agreed well with the theoretical predictions.