Design of Thin Walled Columns for Crash Energy Management — Their Strength and Mode of Collapse

The problem of determining the theoretical load capacity or strength limits of a thin wall, axially compressed column is mathematically complex. Local instability phenomena that precede structural collapse and. the mechanism of collapse add to the complexity. In this paper, a semi-empirical approach is considered in developing design aids for sheet metal box column subjected to axial crush. Various stages of collapse are identified and crush characteristics pertinent to column design are quantified. Both are related to section geometry, column length and the material properties. The size of wave length (fold) is determined and its influence on the folding behavior of rectangular column is discussed. Design equations and charts for sizing thin wall structural elements for crush are presented. Those design aids can be implemented into finite element beam-column codes for study of crash behavior of structural systems.