Simulation and experimental work on manufacturing torispherical heads in explosive hydro-forming process

Abstract

This study presents a numerical investigation on the deformation of the circular blanket against a male die under impulsive loading to form a torispherical heads shape. A finite element model was developed and verified with experimental tests for the explosive forming of the torispherical heads made of AA5083 aluminum alloy in the framework of LS-DYNA crash simulator software. The nature of the deformation was turned from the stretching to the buckling and compression of the specimen by using a male die, which is a novel concept in the high speed forming processes. Johnson-Cook (JC) and Modified Zerilli-Armstrong (MZA) constitutive equations were used to describe the behavior of the specimen in a high strain rate forming process with different stress status. Most of the experimentally observed material behaviors simulated well in pure tension or compression tests, while the transient zone was not adequately described. The predicted width for the transient rim is considerably smaller than experimental measurements. The blast loading process including the underwater detonation and the interaction with the specimen simulated using Arbitrary Lagrangian-Eulerian formulation as well as cavitations and reloading effect. The simulation results for blast loading verified base on Cole’s relation for the underwater detonation of small charges, show a good agreement of 95% accuracy. Key words: Explosive hydro-forming, male die, arbitrary Lagrangian-Eulerian formulation, torispherical head, Johnson-Cook, Zerilli-Armstrong.