Bending collapse behaviour of thin-walled high strength steel under static and dynamic impact loading

Abstract

This paper studies a type of collision that is dangerous to crash worthiness structures and of great interest, the side impact collision. In this study, the bending collapse behavior of thin-walled high strength steel material under side impact was investigated numerically and experimentally. For both static and dynamic side impact loads, the bending collapse behavior such as load carrying capacity, deformation characteristics, and energy absorbing capability were carried out by using three-point bending model. Based on the numerical simulation, those bending collapse responses were predicted and after that this simulation was validated by experimental analysis in cases of static and dynamic bending test. There were two bending specimens for each dynamic and static impacts performed in the experiment. First, the numerical and experimental results showed that the total energy absorption of high strength steel beam in dynamic bending was higher than those in static bending load. Second, the comparison between numerical and experiment pointed out a good agreement with respect to the bending crush force-deformation characteristics at small rotation of beams. Moreover, the effects of geometrical at the corners, mesh size, friction coefficient on the bending resistance behavior is also analyzed and carried out in this study. Namely, in the same bending load, with corner radius, the localized deformation can easily be created than those in right angle corner of beam. The friction coefficient will not affect peak force. The different peak force is predicted as 1% when the coefficicent increases from 0 to 0.2. The empirical formula was founded to be able to predict the ultimate bending moment crush under dynamic bending loads within the effect of strain rates and impact velocities. The good comparison results in terms of dynamic ultimate bending moment between numerical simulation, empirical prediction and experiment indicated the reliability in calculation for dynamic ultimate bending moment under dynamic bending conditions