Energy absorption of discretely assembled composite self-locked systems

Impact accidents cause great damage to lives and devices due to strong destructiveness and weak predictability, and accordingly, flexibility and modifiability are essential in the design of novel impact-resistant structures. To achieve this goal, two newly-designed energy absorption systems were proposed in this paper, which could be discretely assembled without boundary constraints. Quasi-static experiments and finite element method (FEM) simulations were carried out to reveal the deformation mechanism and test the usability, based on which the analytical solutions of the crushing force of the models were established adopting plastic hinge analysis and energy method. Parametric study of multiple-tube systems was conducted to reveal the effects of foam porosity and inner tube parameters on dynamic response, and the optimal design was summarized, achieving the energy absorption efficiency of 39%. The functionally graded design of composite self-locked (CSL) systems was explored, and it was proven that the system with positive stiffness gradient was optimal.