Crashworthiness and energy partitioning in monolithic and layered thin-walled metallic tubes under axial impact

This study numerically investigates the axial impact response of monolithic and layered circular and square-shaped mild steel and aluminium hollow tubes. Tubes of 200 mm length and three equivalent cross-sectional sizes were subjected to low-velocity impact by a 350-kg rigid mass. ABAQUS/Explicit simulations employed S4R shell elements, a strain-rate-dependent Johnson–Cook material model and a general contact interaction algorithm. Deformation and energy absorption in plastic, elastic, and frictional energy components were compared. Force–displacement histories were used to assess mean crushing force, specific energy absorption, and crushing force efficiency. Layered tubes showed increased axial deformation by up to 51.53% for circular sections and approximately 15% for square sections, depending on size. However, monolithic tubes exhibited slightly higher total energy absorption through predominantly plastic dissipation. Moreover, circular tubes demonstrated superior crashworthiness to square tubes, associated with stable deformation modes and more uniform stress distributions. The findings have explored layering-induced deformation and energy dissipation mechanisms.