The collapse mechanism of corrugated cross section beams subjected to three-point bending

In this paper, the collapse behavior of corrugated cross section beams subjected to three-point bending is studied by using the finite element method (FEM). In order to estimate the energy absorption characteristics of the beam, it is essential to estimate the relation between load and deflection in the process of the beam collapse after the peak load. It is found that in the collapse process of the beam the load is decreased by flattening of the cross section of the beam, and that the flattened shape can be quantitatively expressed in terms of the curvature radius of the plane of the top and bottom of the cross section. Based on the energy balance that external work is equated to the flattening deformation energy of the cross section, a new method is proposed for predicting the relation between load and deflection. The validity of the presented method is verified through a comparison with numerical results of FEM analysis under various conditions.

► Collapse mechanism of corrugated cross section beam is analyzed.
► In the collapse process, load decreases mainly due to cross-sectional flattening.
► The flattening can be represented by the curvature of the upper and lower sides.
► Formulas are proposed for relating load and deflection.
► Good agreement is obtained between the proposed theory and the results of FEM.