Axial Crushing of Thin-Walled Tubes With Kite-Shape Pattern

Abstract

Thin-walled tubes are widely used as energy absorption devices in automobiles, designed to protect the costly structures and people inside during an impact event through plastic deformation. They show excellent performance under axial loading in terms of weight efficiency, stroke distance and total energy absorption, but also have the disadvantage that the crushing force is not uniform during deformation process, especially with the existence of a high initial peak force. Recently, pattern design on tubular structures has received increasing attention. It has been found that, if the surface of a tube is pre-folded according to an origami pattern, the collapse mode of the tube can be altered, leading to changes in energy absorption performance. In this paper, we present a series of origami patterned tubes with a kite-shape pattern that is constructed by joining two pieces of Miura-ori. First of all, the geometry of the pattern is presented. We develop a theoretical model to predict the energy absorption associated with the axial crushing of the patterned tubes and derive a mathematical formula to calculate the mean crushing force accordingly. Secondly, a family of origami tubes with various profiles are designed, and their performances subjected to quasi-static axial crushing are numerically investigated. A parametric study is also conducted to establish the relationship between the pre-folded angle of the pattern and the initial peak force as well as the mean crushing force. Numerical results show that introducing patterns to thin-walled tubes offers three advantages in comparison with conventional tubes, i.e., a lower initial peak force, a more uniform crushing load, and a stable and repeatable collapse mode. A 36.0% increase in specific energy absorption and 67.2% reduction in initial peak force is achieved in the optimum case. The new origami patterned tubes show great promise as energy absorption devices.