Experimental and numerical analyses of explosive free forming

Abstract

Abstract Explosive forming of metal blanks is accompanied by large plastic deformations at high strain rates. Mathematical models which include all of the variables in a complete rigorous manner do not exist. However, different aspects of the problem may be dealt width using numerical approximations. These analyses can be used to predict process parameters and can be used to eliminate most of the trial-and-error work, and provide relatively close approximation. In this paper, the explosive free forming simulation of circular aluminum blank is presented. Johnson–Cook and Zerilli–Armstrong equations are used to describe the behavior of blank. The explosive behavior is modeled using JWL equations of state. The models are validated by experiments. The results showed both Johnson–Cook and the Zerilli–Armstrong equations are able to predict the final shape of the blanks properly. However, if the blank material is simulated using the Zerilli–Armstrong equations, the material reaches to its final shape in a shorter time than if the material is modeled using the Johnson–Cook equations. In addition, the optimum stand-off distance ratio ( L / D ) which gives the uniform configuration is obtained for the ratio of 0.167. Numerical results of these simulations show that friction coefficient and blank holder force must be sufficient and optimized in order to prevent uneven drawing and wrinkling.