초록
Energy absorption mechanism of the expansion tube is mainly expansion of the tube diameter by pushing a conical punch into the tube while a bottom of the tube is fixed. In order to improve crash energy absorption capacity of expansion tubes. local buckling characteristics of an expansion tube must be considered, since crash energy absorption significantly decreases while buckling occurs. This paper deals with the dynamic local buckling characteristics and crash energy absorption of the expansion tubes during tube expanding process. Static local buckling loads can be predicted by modified Plantema equation. In this study. dynamic term is added to modified Plantema equation for considering strain rate effect of buckling. The tube shape that has maximum crash energy absorption capacity can be obtained by comparing between dynamic modified Plantema equation and numerical analysis of expansion tubes.