The article presents the results of numerical crush simulations of thin-walled structures with a square cross-section and partial filling with foamed material. The influence of the length of the filling on the values of the energy efficiency index was analysed. Four types of foamed material were subjected to numerical analysis. The research was conducted using FEM in Abaqus 6.14 program. The obtained results were presented in the following forms: load-shortening characteristics, tables and diagrams. The best energy absorbing properties are shown by models filled with aluminium and polyethylene terephthalate foam.