Title: Influence of deployable hood systems on finite element modelled brain response for vulnerable road users

Authors: Rikard Fredriksson, Liying Zhang, Ola Bostrom

Addresses: Karolinska Institutet, Stockholm, Sweden; Autoliv Research, Vargarda, Sweden. ' Wayne State University, 818 W. Hancock, Detroit, MI 48202, USA. ' Autoliv Research, Vargarda, Sweden

Abstract: Using full-scale Polar II adult dummy tests as input, a free-flying angled head-to-hood component test method was developed, and tests were performed at two different impact configurations at a test speed of 40 km/h. Both linear and rotational head acceleration were measured and used to drive the Wayne State University Head Injury Model (WSUHIM). The dummy tests showed small pre-impact head accelerations (<1000 rad s−2) and neck moments (<35 Nm). In all dummy tests, the rotational acceleration reached the highest levels about the X-axis. For a small under-hood clearance and using three different head impact configurations (one dummy and two impactors), a strain level of 0.35 was experienced by 22-42% of the brain volume; for a large under-hood distance, a strain level of 0.35 was experienced by only 2-5% of the brain volume at some time during the event (approximately a ten-fold reduction).

Keywords: pedestrians; vulnerable road users; deployable hoods; pop-up hoods; FEM; finite element method; mathematical modelling; brain injury; head injuries; full-scale dummy test; rotational-angular acceleration; brain response; head-to-hood impact; vehicle safety.

DOI: 10.1504/IJVS.2009.026972

International Journal of Vehicle Safety, 2009 Vol.4 No.1, pp.29 - 44

Received: 12 Nov 2008
Accepted: 26 Jan 2009

Published online: 11 Jul 2009 *

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