Integration of a Composite Crash Absorber in Aircraft Fuselage Vertical Struts

A crash absorber element integrated in composite vertical (z-) struts of commercial aircraft fuselage structures was developed, which absorbs energy under crash loads by cutting the composite strut into stripes and crushing the material under bending. The design concept of this absorber element is described and the performance is evaluated experimentally in static, crash and fatigue test series on component and structural level under normal and oblique impact conditions. These tests highlight the robustness of the absorber design as this system worked under various conditions and angles with an impressively high reproducibility. The physics of the energy absorption by high rate material fragmentation are explained and numerical modelling methods in explicit finite element codes for the simulation of the crash absorber are assessed. The real physical fragmentation phenomena can just be approximated in simulations, emphasising that the numerical prediction of composite energy absorption for industrial use cases is still a big challenge.