Effect of hole shapes and dimensions on the crushing performance of octagonal multi-cell columns

Thin-walled columns are frequently employed in vehicle structures to diminish the damages resulting from vehicle collisions. In this research, the effect of hole shapes and dimensions on crushing behavior of octagonal multi-cell columns subjected to longitudinal loading is studied. Rectangular, hexagonal and elliptical holes are assumed on the octagonal multi-cell columns, and crushing parameters (i.e. specific energy absorption SEA and maximum crushing force Fmax) are then obtained by performing numerical analyses in LS-DYNA. The results demonstrate that creation of holes on column walls improve crushing capability significantly, such that creation of rectangular, hexagonal and elliptical holes on the octagonal multi-cell columns increases the value of SEA by 37%, 42% and 39%, respectively in comparison to the plain octagonal column. On the other hand, presence of holes on the octagonal columns results in reduction of Fmax (as a negative crushing indicator).