I need a complete Fortran subroutine for low speed impact of foam sandwich structure and can be associated with abaqus (a very complete subroutine is required. In abaqus, the model I built is aluminum alloy AL-5754 panel, the panel uses Johnson Cook damage, the plasticity is Johnson Cook hardening, and the core layer is PET crushable foam model). Please ask if there is any open source subroutine code that can be used