Finite element analysis of the effect of motorcycle helmet materials against impact velocity

A motorcycle helmet is the best protective headgear for the prevention of head injuries caused by direct cranial impact. A finite element model based on realistic geometric features of a motorcycle helmet is established, and explicit finite element LS-DYNA code is employed to simulate dynamic responses at different impact velocities. Peak acceleration and Head Injury Criterion values derived from the headform are used to assess the protective performance of the helmet. We have concluded that the dynamic responses of the helmet dramatically vary with impact velocity, as well as the mechanical properties of the outer shell and energy-absorbing liner. At low velocities, e.g., less than 8.3 m/s, the shell stiffness and liner density should be relatively low to diminish head-contact force. At high velocity, e.g., 11.1 m/s, a stiffer shell and denser liner offer superior protection against head injuries.