Virtual Testing Applied to Door Latch Performance Evaluation

Vehicle door latch minimum force capability testing presently utilizes uniaxial quasi-static loading conditions created toward the middle of the last century. Current technology enables more sophisticated virtual testing of a broad range of systems. Door latch failures have been observed in vehicles under a variety of conditions. Typically these conditions involve multiple axis loading conditions. The loading conditions presented during rollovers on passenger vehicle side door latches are not currently evaluated. Background on these conditions is reviewed. Rollover crash test results, rollover crashes and physical FMVSS 206 latch testing are reviewed. In this paper, the creation and validation of a passenger vehicle door latch model is described. The multi-axis loading conditions observed in virtual rollover testing at the latch location are characterized. These loads are then applied to the virtual testing of a latch in both the secondary and primary latch positions. The results are then compared with crash test and real world rollover results for the same latch. The results indicate that while a door latch in the secondary latch position may meet minimum existing uniaxial horizontal plane loading requirements, the incorporation of multi-axis loading conditions may result in failure of the latch to accomplish its intended purpose at loads substantially below the FMVSS 206 uniaxial failure loads. The findings suggest the need for reexamining the relevance of existing door latch testing practices in light of the prevalence of rollover impacts and other impact conditions in today’s vehicle fleet environment.