Abstract
The expansion tube used as a crash energy absorber dissipates the kinetic energy through internal deformation energy of the tube and frictional energy. In this paper, the effect of the variation of punch angles on energy absorbing characteristics of expansion tubes was studied by quasi-static tests with three punch angles (15°, 30° and 45°). Finite element method of the tube expanding process applying a shear friction model were carried out to confirm the variation of shear friction factor with respect to punch angles. In addition, additional analysis were performed with the angle of 20°, 25°, 35°, 40° to study the effect of the punch angles on total energy, internal deformation energy and frictional energy. The result of the experiment and finite element analysis showed that the shear friction factor was inversely proportional to the punch angles and a specific punch angle existed at which the absorbed energy didn't increase anymore.
Keywords: Expansion tube, Crash energy, Internal deformation energy, Frictional energy