External inversion of thin-walled corrugated tubes

A thin-walled circular tube is known to be able to invert externally under axial compression when it is placed upon a profiled rigid die. Such a structure has become a promising candidate for energy absorbing applications due to its high reaction force and good load uniformity. However, the inversion process could become rather unstable when imperfections are present and the friction between the tube and die is high, which largely limits its application. In this paper, we propose the use of corrugated thin-walled tubes. Both simulation and experimental results show that thin-walled corrugated tubes can have a much more stable inversion in comparison with their circular counterparts. They are less sensitive to the surface imperfections, and no stringent requirement of lubrication on the die is necessary. Our research has paved the way for such devices to be used as an effective energy absorption device in many practical applications.