The study of the chin bar standard problem of motorbike helmet

The craniofacial injuries for motorcyclists are widespreading and serious problems around the world. The incidence and severity of brain injuries resulted from facial and cranial injuries are almost the same. However, the motorbike helmet has drawn a lot of research attention in preventing brain injuries while the chin bar, which protects face impact directly, has been ignored for a long time. Snell Memorial Foundation of U.S.A and British are the few that have enacted the safety standard for the chin bar. Nevertheless their basic concepts are different from each other, and only the integral stiffness between chin bar and helmet is evaluated, which cannot represent the real world situation when accidents occur. A testing procedure for the chin bar was hence established in this study: a standard metal headform was secured to the helmet with a chin bar, then dropped face down along a rail to impact a flat steel anvil on the floor. The impact energy, acceleration and Gadd's severity index were measured from the headform as judgment criteria. The results, compared with the Snell and British standard, show that both standards testing methods were unrealistic. Therefore, the chin bars which were approved by the above standards could not prevent the brain injuries resulted from the face impact.