Influence of Extruded Tubing and Foam-Filler Material Pairing on the Energy Absorption of Composite AA6061/PVC Structures

There is accelerating demand for energy-absorbing structures fabricated from lightweight materials with idealized, near-constant force responses to simultaneously resolve the engineering challenges of vehicle mass reduction and improved occupant safety. A novel compounded energy dissipation system composed of AA6061-T6 and AA6061-T4 tubing subjected to hybrid cutting/clamping and H130, H200 and H250 PVC foam compression was investigated utilizing quasi-static experiments, finite element simulations and theoretical modeling. Identical structures were also subjected to axial crushing to compare with the current state of the art. The novel cutting/foam crushing system exhibited highly stable collapse mechanisms that were uniquely insensitive to the tube/foam material configuration, despite the disparate material properties, and exceeded the energy-absorbing capacity and compressive force efficiency of the axial crushing mode by 14% and 44%, respectively. The simulated deformation profiles and force responses were consistent with the experiments and were predicted with an average error of 12.4%. The validated analytical models identified numerous geometric/material configurations with superior performance for the compounded AA6061/PVC foam cutting/foam crushing system compared to axial crushing. An Ashby plot comparing the newly obtained results to several findings from the open literature highlighted the potential for the compounded cutting/foam crushing system to significantly outperform several alternative lightweight safety systems.