Evaluation of the effective mass of the body for helmet impacts

Currently available motorcycle helmet standards employ headforms to assess the impact absorption capability of helmets. The mass and size of the headforms are similar to those of the human head. This fact implies that the standards rely on the assumption that the effect of the rest of the body on the performance of the helmet during impact is negligible. In this study, by using validated finite element (FE) models of a commercially available helmet and of the human body, full-body helmet impacts are simulated. Even within the short duration of the impacts (less than 10 ms), the body interacts with the head, leading to further crushing of the helmet liner. To include this effect in the headform impacts, the mass of the headform is increased. The added mass is determined for various impact configurations. It is found that the added mass is not dependent on the properties of the helmet; thus, it can be adopted by the impact absorption test of standards.