Assessment of Bicyclist Head Injury Risk under Tangential Impact Conditions

Although cycling may be attractive for both economic and environmental reasons, cyclists are extremely vulnerable road users and subjected to falls or collisions with cars. Therefore, wearing a helmet is of crucial and vital importance considering the high percentage of head injuries in cyclists. The present research attempts to understand the degree of protection offered by a commercial bicycle helmet under realistic oblique impact conditions. Experimental research was carried out on an existing helmet to perform 2 oblique impact situations at ambient temperature. In parallel, the helmet was digitized and meshed to produce a finite element model (FEM) that was implemented under the PamCrash® crash code. Coupled to a 50 percentile Hybrid III dummy head FEM, the experimental tests were numerically reproduced in order to provide a validation of the helmet model under tangential impact conditions. Then, coupled to a detailed human head model in order to assess the head injury risk under tangential impact, results showed that even if frontal oblique impacts are more critical than lateral ones, computed injury risks are acceptable for a realistic head impact condition as extracted from bicyclist accident analysis.