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Affiliation
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Collision Research & Analysis, Inc. , 2209 West 190th St., Torrance , California 90504. |
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Abstract
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PURPOSE This study collected and analyzed available testing of motor vehicle seat strength in rearward loading by a body block simulating the torso of an occupant. The data was grouped by single recliner, dual recliner and ABTS (all belts to seat) seats.
METHODS The strength of seats to rearward loading has been evaluated with body block testing from 1964-2008. The database of available tests includes 217 single recliner, 65 dual recliner and 18 ABTS seats. The trends in seat strength were determined by linear regression and differences between seat types were evaluated by the Student t-test. The average peak moment and force supported by the seat was determined by decade of vehicle model year (MY).
RESULTS Single recliner seats were used in motor vehicles in the 1960s-70s. The average strength was 918 ± 224 Nm (n = 26) in 1960s and 1,069 ± 293 Nm (n = 65) in 1980s. There has been a gradual increase in strength over time. Dual recliner seats started to phase-into vehicles in the late 1980s. By 2000s, the average strength of single recliner seats increased to 1,501 ± 335 Nm (n = 14) and dual recliner seats to 2,302 ± 699 Nm (n = 26). Dual recliner seats are significantly stronger than single recliner seats for each decade of comparison (p<0.001). The average strength of ABTS seats was 4,395 ± 1,185 inlb for 1989-2004 MY seats (n = 18). ABTS seats are significantly stronger than single or dual recliner seats (p<0.001). The trend in ABTS strength is decreasing with time and converging toward that of dual recliner seats.
CONCLUSIONS Body block testing is an quantitative means of evaluating the strength of seats for occupant loading in rear impacts. There has been an increase in conventional seat strength over the past 50 years. By the 2000s, most seats are 1,700-3,400 Nm moment strength. However, the safety of a seat is more complex than its strength and depends on many other factors.
Language: en |