Energy-Absorbing Origami Structure for Crashworthiness Design

Abstract

This paper presents experimental and numerical investigations on the origami-patterned tube which is acknowledged as a promising energy-absorption device. Its buckling mode leads to high performances in terms of specific energy absorption (SEA) and crush force efficiency (CFE). The polygonal tube is prefolded by following an origami pattern, which is designed to act as geometric imperfection and mode inducer. First, a series of quasi-static crushing tests are performed on origami tubes with different materials and geometrical features. Specimens in SUS316L and AlSi10Mg are produced through Additive Manufacturing (AM). It allows to conveniently produce few samples with a complex shape. Finite Element Analysis (FEA) and Direct Image Correlation (DIC) are employed for a better insight into the complex crushing behaviour. The Aluminum tube shows a brittle behaviour while SUS316L tubes have extremely promising performance until local crack happens. Limits stemming from the employment of AM are explored and a new geometry is designed to avoid cracking. Second, a numerical design exploration study is carried out to assess the sensitivity of origami pattern features over the energy-absorption performance. ANSYS Autodyn is utilized as FE solver and DesignXplorer for correlation and optimization. The benefits of new patterns are investigated through geometrical optimization, and an improved geometry is proposed. The pattern stiffness is tuned to account for the external boundary conditions, resulting in a more uniform crushing behaviour. A similar force trend is maintained with a SEA increment of 51.7% due to a drastic weight reduction in areas with lower influence on post-buckling stiffness.