1 Explosive Welding Simulation of Double Layer Tubes (7039 Aluminium - 4340 steel) R. Alipour 1 , K. Mostajiri 2 , I. Golshkooh 3 and F. Najarian 4 1- Department of Mechanic, Islamic Azad University of Mahshahr, Iran 2- Department of Mechanical Engineering – Engineering Faculty – Islamic Azad University of Shooshtar – Iran 3- Department of Mechanic, Islamic Azad University of Iseh, Iran 4- Department of Metal Industries, Islamic Azad University of MIS, Iran Corresponding Author E-mail: R.Alipour@mahshahriau.ac.ir Abstract Explosive welding is a process which uses explosive detonation to move the flyer plate material into the base material to produce a solid state joint. Experimental tests have been carried out by other researchers; have been considered to explosively welded aluminum 7039 and steel 4340 tubes in one step. The tests have been done using various stand-off distances and explosive ratios. Various interface geometries have been obtained from these experiments. In this paper, all the experiments carried out were simulated using the finite element method. The flyer plate and collision velocities obtained from the analysis were validated by the pin-measurement experiments. The numerical results showed that very high localized plastic deformation produced at the bond interface. The Ls_dyna_971 FEM has been used for all simulation process. Keywords: Explosive Welding, Johnson-Cook Equation, Finite Element, JWL Equation 1 Introduction Explosive welding is an area of study that represents a truly multidisciplinary research as it deals with the dynamics of collision at high velocities and pressures, the transient fluid like behaviour of metals at extremely high strain rates, metallurgical and other physical aspects of colliding metals, modeling of material behavior, sources of high rate energy and the geometrical parameters of colliding system of metals. To analyze the process, the hydrodynamic analogy was used by various authors [1, 2, and 3] due to the creation of the high localized pressure and the material fluid like behavior at the collision zone. The process parameters are the impact velocity, the collision point velocity, the angle, the stand-off distance, the type of the explosive used and the detonation velocity, density and size and distributions of the explosive mix. Welding windows were proposed to show the weld ability ranges of process parameters i.e. impact velocity (or collision point velocity) versus the dynamic angle for various materials [3, 4, 5, and 6]. Nevertheless, the data were obtained by means of large number of experiments performed. However, the process could be simulated using the 1- lecturer in mechanic (Corresponding Author) 2- lecturer in mechanic 3- lecturer in mechanic 4- lecturer in mechanic