DYMAT 2009
Volume 2, 2009
DYMAT 2009 - 9th International Conference on the Mechanical and Physical Behaviour of Materials under Dynamic Loading
Page(s) 1839 - 1845
Section Numerical Simulations
Published online 15 September 2009
DYMAT 2009 (2009) 1839-1845
DOI: 10.1051/dymat/2009258

Determination of the constants of material models by optimization and numerical simulation

G.H. Majzoobi1, S. Khosroshahi2 and H. Beikmohahhadloo2

1  School of Mechanics, Azad University of Takestan, Takestan, Iran
2  Mechanical Engineering Department, Bu-Ali Sina University, Hamadan, Iran

Published online: 15 September 2009

Material models are essential requirements in numerical simulation of mechanical behavior of materials in particular at high strain rates and at elevated temperatures. The models involve a number of constants to be determined normally by experiment. In this investigation a combined experimental, numerical and optimization technique is employed to obtain the constants of Johnson-Cook model in tension. The experiments are conducted on a high rate tensile testing apparatus called “Flying Wedge”. The apparatus is also simulated using finite element method. The experiments are simulated using the same specimen geometries and the apparatus. The differences between the deformed shapes of the specimens from the experiments and the numerical simulations are taken as the objective function for optimization purposes. The simulations of the tensile tests are repeated for various values of the material constants which are the variable vector in optimization. The optimum constants are then obtained using generic algorithm. The results verified by a number of measures prove to be very encouraging. The results also suggest that the approach given in this work can substitute expensive instrumentations usually used for capturing stress-strain curves at high strain rates and elevated temperature.

© EDP Sciences 2009