This study compares pressure and load patterns on the seat back generated by humans to those by Hybrid III dummies in low-severity rear impacts. 12 healthy human subjects, along with the 5th percentile female and 50th percentile male Hybrid III dummies, were used as test subjects. During the tests, the interface pressure distribution between seat and human or dummy was collected by means of a Tekscan system, at a rate of 50 frames/sec. The test seat was mounted to a mini-sled, which was powered by a bungy cord. The bungy cord accelerated the sled to a speed of about 1.3 m/s (5 km/h) when the sled was brought to stop by means of a hydraulic damper. The stopping distance was approximately 30 mm which generated a deceleration pulse of about 3G. The results showed that at impact peaks, total dynamic loading due to human or dummy trunk weight on the seat back increased from static loading. Not only dummy loading increased more than human loading, but also for dummies, a larger portion of load transferred from lower back to upper back region. The dummies' load centre in these tests migrated up on seat back more than 50 mm as compared to 20 mm for the humans during impacts. Pressure distribution patterns differed significantly between the humans and the dummies. The results of the study will help improve the understanding of injury mechanism due to rear impact, and provide fundamental data for dynamic human modelling. (A)
Abstract