Background The German hang-glider association reports that approximately 60% of serious injuries resulting from hang-glider accidents are to the spine. The market-approval of back protectors encompasses an impact test.
Objective When the impact test was introduced, information concerning accident situations was scarce. The objective of this study is to investigate how the impact test can be improved.
Design Relevant load cases were derived from a survey among 61 pilots which have sustained a spinal injury in a paragliding accident. Paragliding accident videos were analysed in terms of impact velocities and angles. Based on the gathered information an enhanced test procedure was proposed. A Finite Element model of a harness was created and validated against impact tests. The baseline model's performance was evaluated according to the enhanced impact test procedure.
Risk factor assessment The performance was rated using the Dynamic Response-model (DR) and the maximum acceleration.
Results The current impact test covers approximately 50% of impact scenarios. In terms of impact velocity far less than 25% of impacts are covered by the current test procedure.
Conclusions An enhanced test procedure with a vertical impact velocity of 8m/s and an impactor mass of 80 kg is suggested, considering impacts to the side, to the front, to the rear and to the bottom of the protector. The enhanced test procedure covers 80% of impact scenarios, 50% of impact velocities and about 50% of occupants in terms of weight. For the evaluation of injury risk the DR was suggested, as it is sensitive to the load direction. It is shown that current protectors will likely fail in the enhanced test procedure. However, the FE study also shows that room for improvement still exists with regards to the shape of protectors and materials used.
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