J. Cirne, R. Dormeval, et al.
J. Phys. IV France 134 (2006) 69-74
Constitutive equations for multiphase TRIP steels at high rates of strainJ. Van Slycken1, P. Verleysen1, J. Degrieck1 and J. Bouquerel2
1 Mechanics of Materials and Structures, Dept. of Mechanical Construction and Production, Ghent University, 9000 Ghent, Belgium
2 Laboratory of Iron and Steelmaking, Dept. of Metallurgy and Materials Science, Ghent University, 9000 Ghent, Belgium
Published online: 26 July 2006
Multiphase TRansformation Induced Plasticity (TRIP) steels show an excellent combination of high strength and high strain values, making them ideally suited for use in vehicle body structures. A complex synergy of three different phases (ferrite, bainite and austenite) on the one hand, and the meta-stable character of the austenite on the other hand, give the material indeed a high energy absorption potential. The knowledge and understanding of the dynamic behaviour of these sheet steels is essential to investigate the impact-dynamic characteristics of the structures. Therefore split Hopkinson tensile tests are performed in a strain rate range of 500 to 2000 s-1. Three TRIP steel grades with a different Al and Si content were studied. The experimental results show that these steels preserve their excellent shock-absorbing properties in dynamic conditions. The typical high strain rate loading conditions and the complex behaviour of TRIP steels offer a unique investigation opportunity. This behaviour can be described with phenomenological material models that can be used for numerical simulations of car crashes. The Johnson-Cook model, a frequently used model in finite element codes, is well-suited to describe the dynamic behaviour of the investigated TRIP steels. This model is compared to the Rusinek-Klepaczko model.
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