Bicycle helmet design

Finite-element analysis (FEA) was used to consider the improvement of bicycle helmet performance, in oblique impacts with the road. The events, predicted by FEA, were described and the peak head accelerations interpreted in terms of a simplified model. FEA shows that thicker foam liners of lower compressive yield stress can protect the head against linear acceleration in 150 J impacts. The peak rotational acceleration of the head was shown to be only slightly affected by the friction coefficient on the road and, in general, to be insufficient to cause serious diffuse brain injuries. Improved protection of the forehead and temple was investigated; this required extending the liner downwards at the sides and front, and the inclusion of an oblique impact test in the BSEN 1078 standard.