Title: Modified Johnson-Cook model for vehicle body crashworthiness simulation

Authors: W.J. Kang, S.S Cho, H. Huh, D.T. Chung

Addresses: Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, 373-1 Kusongdong, Yusongu, Taejon 305-701, Korea. ' Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, 373-1 Kusongdong, Yusongu, Taejon 305-701, Korea. ' Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, 373-1 Kusongdong, Yusongu, Taejon 305-701, Korea. ' Department of Mechanical Engineering, Korea Institute of Technology and Education, 37-1, Gajeonri, Byungchonmyon, Chonan, Chungnam 333-860, Korea

Abstract: Dynamic response prediction of vehicle bodies is important for vehicle crashworthiness evaluation. The dynamic behaviour of vehicle body materials is dependent on material strain rates. One of the typical high strain rate tensile tests is the split Hopkinson bar test. In this paper, experiments have been conducted based on a new split Hopkinson bar apparatus specially designed,for the dynamic tensile test of sheet metals. Results from both quasistatic and dynamic tests show that the strain rate hardening effect for sheet metals cannot be described by the original Johnson-Cook constitutive relation. This relation has been modified to include a higher-order term for the hardening effect. The modified constitutive relation represents a more accurate simulation than the original model for the dynamic behaviour of vehicle body structures.

Keywords: vehicle crashworthiness simulation; modified Johnson-Cook model; sheet metal testing; split Hopkinson bar; dynamic response prediction; vehicle bodies; vehicle body materials; material strain; tensile testing; strain rates; dynamic behaviour; hardening.

DOI: 10.1504/IJVD.1999.005594

International Journal of Vehicle Design, 1999 Vol.21 No.4/5, pp.424 - 435

Published online: 21 Oct 2004 *

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