Quantifying parameters of the seat-occupant interface during simulated low speed rear-impact collisions

Abstract

The influence of supplemental lumbar support on automobile seat surface pressures was measured during simulated rear impact collisions with human volunteers. Men and women (age = 25.4 ± 3.4 years; BMI = 25.2 ± 3.9; stature = 1.73 ± 0.06 m) experienced two low-velocity rear impact collisions. Simulated collisions with and without a lumbar support were conducted in random sequence. Using a pressure sensing mat that contained 2288 ferroresistive sensors, seatback pressure was recorded at a rate of 500 Hz. These data were used to compute the total seatback force, area of force concentration, and centre-of-force (CoF). Total seatback force was not significantly different from body mass for either men or women (≈1.2 × body mass). Average contact area of the occupant's back with the seatback (i.e., area of force concentration) was approximately 221.3 cm2 and 100.1 cm2 greater without supplemental lumbar support for men and women, respectively. With respect to the L4 spinal level, the CoF had a greater vertical distance without lumbar support and a greater horizontal distance with lumbar support. In conclusion, the lumbar support used in this study altered the location and distribution of seatback forces applied to the occupant's back.