Multi-Scale Modelling of Deformation and Fracture in Aluminium Foam for Crashworthiness Applications in Nigerian Automotive Design

This study develops a multi-scale modelling framework for deformation and fracture in closed-cell aluminium foam targeted at crashworthiness applications in automotive components, with reference to Nigeria's growing local vehicle assembly and body fabrication industry. Aluminium foam is an advanced lightweight material with high specific energy absorption, and its adoption in bumper and pillar applications could significantly improve occupant protection in locally assembled Nigerian vehicles. A hierarchical multi-scale approach is implemented, coupling a unit cell finite element model at the mesostructure scale with a continuum damage mechanics model at the macroscale, implemented in Abaqus. The mesostructure model is derived from computed tomography scans of Al-SiC stabilised foam specimens produced at laboratory scale. The Gurson-Tvergaard-Needleman porous plasticity model is calibrated against uniaxial and biaxial compression tests. Dynamic impact simulations representative of automotive crash conditions (20, 40, and 60 km/h rigid barrier impact) are performed using the calibrated multi-scale model, and energy absorption efficiency is compared between foam-filled and unfilled hollow aluminium structural sections. Experimental quasi-static and dynamic compression tests on foam specimens fabricated using local aluminium alloy AA1100 validate the modelling results. Findings demonstrate that foam-filled sections improve specific energy absorption by 2.8 times relative to unfilled sections at equivalent mass. The study provides a design tool framework for foam-filled crashworthy structures. Keywords: aluminium foam, multi-scale modelling, crashworthiness, automotive, deformation.