Influence of flange location on axial deformation stability of double-hat structure

A new structural configuration with better impact stability for increasing energy absorbing efficiency is found. Based on finite element analysis, deformation modes of double-hat structure under axial impact loading are categorized to find the main reasons that affect deformation stability. It is revealed that, in a double-hat structure, the location of the flanges is highly related to the deformation mode and energy absorbing efficiency. Moving the flanges away from their traditional mid-location may result in more regular and stable deformation mode and achieve higher energy absorbing efficiency. The flange offset value needs to be controlled within a certain range, otherwise, the double-hat structure would tend to deform like a top-hat structure and the energy absorbing efficiency could be compromised. These findings and analyses lead to a new structural design configuration-asymmetric flange locations—for enhancing the deformation mode stability in double-hat structures.