Multiscale modelling of hybrid glass fibres reinforced graphene platelets polyamide PA6 matrix composites for crashworthiness applications

This work investigates the crashworthiness response for a hierarchical modelling of hybrid composite material consisting of short-glass fibres reinforced graphene platelets polyamide PA6 matrix. A multiscale approach, using both mean-field homogenisation and finite element FE techniques, is employed to derive the overall response. Graphene is considered as platelets GPL embedded within an elasto plastic matrix phase. The 2-phases composite response is, therefore, computed under the Mori-Tanaka micromechanics scheme by accounting for the GPL spatial orientation. The modelling of hybrid 3-phases composites consists of a hierarchical double-scale approach, which includes the 2-phases GPL/polymer composite and short glass fibres as reinforcements. Numerical characterisations involving tensile, compression, fracture toughness and Charpy impact tests enable the determination of damage/failure thresholds for crashworthiness applications. The full crash box is simulated by implementing the constitutive 3-phases composite using a user-defined Digimat/LS-DYNA linkage. Numerical results, which are compared to those from conventional steel and glass fibres composites, show the contribution of the GPL volume fraction in the improvement of the specific energy absorption SEA.