The Crashworthiness Behaviour of Thin Walled Aluminium Extruded Tubes with Varying Polygonal Cross Sections

The  finite  element  code,  LS-DYNA,  was  used  to  investigate  the  energy  dissipation characteristics  of AA6060-T4  aluminium  alloy  extruded  tubes  with  varying  polygonal (i.e.,  hexagonal  and octagonal)  cross  sections  subjected to  axial  impacts.  The research study was conducted  in two  phases.  The first  phase comprised  of validating the finite element  model  parameters  and  numerical  results  of  thin-walled  aluminium  extruded square tubes with actual  published  experimental data.  The mean dynamic axial crushing force  value  was  predicted  within  ±  3%,  and  in  the  case  of  the  permanent  axial displacement,  the  accuracy  was  within  ±  5%,  when  compared  to  the  published experimental results.  The second phase results of the numerical simulations pertaining to the  hexagonal  and  octagonal  tube  sections  were  compared  to  the  benchmark  results established  for  the  square  section  tubes.   The  numerical  simulation  results  for  the hexagonal  section tube revealed  a minimum average increase in the  mean dynamic axial crushing  force  and  permanent  displacement  parameters  of  10%  and  11%,  respectively, over the baseline square tube sections.  The octagonal tube section showed a mimmum average  increase  in  the  mean  axial  crushing  force  and  permanent  displacement parameters of 25% and 20%, respectively.