Simulation of Blunt Abdominal Impacts caused by Handlebar Ends during Bicycle Crashes with the PIPER Child Model

In bicycle crashes of children with handlebar-related injuries, the abdomen is the most frequent injured body region by far. Despite this, however, existing legislation and published studies have in the past been focused primarily on the protection of the head. This study thus investigates blunt traumatic abdominal injuries caused by handlebar ends using a detailed finite element model (PIPER child model). Two impact configurations resulting from bicycle crashes were found to be typical and were therefore replicated. Simulations were performed with four handlebar ends, based on commercially available models (three-dimensional laser scanned) and a sensitivity analysis was conducted with five generic models. The trends observed during both abdominal impact scenarios were generally consistent. Our study shows a reduction for the analysed injury metrics in dependence on both the stiffness and the shape of the handlebar ends. Handlebar ends with increased softness in particular showed considerably reduced peak values for abdominal deflection, viscous criterion and organ strains. Moreover, shape was found to be of great relevance in the issue of the impact angle relative to the abdominal wall. The findings highlight the importance of dedicated impact protection on handlebar ends for children bicycles in order to reduce the severity of the injuries sustained during a blunt abdominal impact.