Analysis of the proposed frontal oblique crash test

Barbat, Saeed; Li, Xiaowei

Affiliations

Abstract

On December 2015, The National Highway Traffic Safety Administration (NHTSA) published a Request for Comments (RFC) and proposal to implement U.S New Car Assessment Program (NCAP) changes covering three categories of crashworthiness, crash avoidance and pedestrian protection, beginning with the 2019 model year. The crashworthiness included a new frontal oblique impact (OI) test protocol. The test compromises of a new Oblique Moving Deformable Barrier (OMDB), new THOR 50th percentile male (THOR- 50M) anthropomorphic test device, and a new test configuration. An OMDB of 2,486 kg (5,480 lb) impacts a stationary target vehicle at a speed of 90 kph (56 mph) at an angle of 15 degrees with a 35% barrier overlap with the front end of the vehicle. This paper describes the analyses of a 31 OI tests conducted by NHTSA, in which the target vehicles used were of different sizes and weight distribution ranging between 1034 Kg (SMART)-2624 Kg (Silverado).

Target vehicle Deformation Energy (DE) in each of the 31 OI test was determined and compared to its 56 kph (35 mph) dummy responses for each test were plotted against Velocity Change (Delta V) calculated from momentum equation and from test’s velocity time histories. In addition, Barrier Equivalent Velocity (BEV) of target vehicles was calculated and the THOR M50 dummy responses were plotted against BEV and presented in this paper. Results indicated that target vehicles absorb more DE in the proposed OI compared to a 56 kph (35 mph) full frontal barrier impact. Lighter weight vehicles, in particular, have to manage approximately 50- 60% more DE in the proposed OI. Larger vehicles (i.e., similar weight to the OMDB) manage approximately same DE as in the 56 kph (35 mph) full frontal barrier impact. Therefore lighter vehicles will require significant structural stiffening which may have negative impacts on other attributes such as Fuel Economy, vehicle compatibility and stiffer crash pulse or restraint system in small light weight vehicles, which may lead to safety degradation for rear seat occupant, elderly in particular. Biomechanics injury risk indicates that occupant’s injury risk increases with the velocity change experienced by the occupant during a crash. Injury risk associated with THOR-M50 dummy responses in NHTSA’s OI tests showed weak or no correlations with velocity change. The same responses were plotted against BEV and showed similar results and observation. The proposed OI mode did not demonstrate the expected injury trend with velocity change and/or BEV. Other issues may exist with the barrier mass, stiffness, THOR or test configuration. Further research is needed to develop appropriate OI test parameters, OMDB, and dummy type and/or criteria.

Links

URL: http://indexsmart.mirasmart.com/25esv/PDFfiles/25ESV-000130.pdf

Cited Works (3)

Year	Entry
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2011	Rudd RW, Scarboro M, Saunders J. Injury analysis of real-world small overlap and oblique frontal crashes. In: Proceedings of the 22nd International Technical Conference on the Enhanced Safety of Vehicles (ESV). June 13-16, 2011; Washington, DC.