Seat belt assemblies are tested prior to vehicle crash tests in accordance with the UNECE R16 regulation. Thanks to these tests, global verifications of the restraint system performance are performed. Nevertheless, this common method is inadequate to analyse the local behaviour of seat belt components such as D-ring stability, because small variations of the dummy or the belt positions can create high perturbations in the test results. Besides, the cost of classical crash tests prevents planning test campaigns from focusing on the effect of these tiny variations. In this paper, an innovative test method is proposed to analyse webbing/D-ring/retractor subsystem of a seat belt assembly in a fully controlled manner. A test method is studied and evaluated by finite element analysis. An experimental bench is described and validated during a drop test campaign. Several load cases are described and a case of seat belt bunching phenomenon is reproduced. (Author/publisher)
Abstract