A study on motorcyclist head reponses during impact against front end of vehicle

Motorcycle to vehicle impact accidents occur frequently in real world and often cause serious brain injuries and deaths of motorcyclists. This study aims to research the motorcyclist head responses and helmet protection performance at common motorcycle-vehicle impact scenarios. First, multi-body system (MBS) models of motorcycle-vehicle impact were developed to investigate motorcyclist's head and vehicle conditions (position, orientation and velocity) at the time of head impacts with vehicle. Then, the impact conditions were input to finite element (FE) models of head striking vehicle to obtain the head tissue level responses, such as coup pressure, von Mises stress, first principal strain and skull stress. Influences of impact velocity, impact angle, and helmet usage on head responses were investigated by conducting parametric studies. The results show that motorcycle and vehicle initial speeds and impact angles influence motorcyclists' head impact locations on vehicles and head responses. Coup pressure and skull stress have strong relationships with head impact forces, while von Mises stress and first principal strain are sensitive to head equivalent impact velocity combining of normal and tangential velocities. Helmet shows a clear effectiveness in reducing brain pressure and skull stress, while its influences von Mises stress and first principal strain in brain subtly.