Numerical Study on High Velocity Impact Welding Using a Modified SPH Method

Abstract

High velocity impact welding (HVIW) involves processes like the impact of metal structures and strong fluid-structure interactions with complex phenomena such as interfacial waves and jet generation. It is very difficult to model the HVIW process with typical physics well captured due to the large deformation and moving interfaces, while the associated mechanisms inherent in HVIW are also not well understood. In this paper, the HVIW process is simulated using a modified smoothed particle hydrodynamics (SPH) model, in which the kernel gradient correction is used to improve computational accuracy and an artificial stress term is used to ease stress instability during the welding process. The mechanisms in HVIW are investigated, and typical phenomena including the wavy interface, jet formation, interfacial temperature and pressure distribution are captured. It is demonstrated that with proper impact welding velocity and initial welding angle, the modified SPH method can well reproduce the morphology evolution of the welding interface from straight to wavy and further to wavy interface with vortex shedding. Based on comprehensive numerical data from SPH simulations, the weldability windows for the HVIW are obtained and are compared with experimental and theoretical results. Welding limits for HVIW are also discussed in detail.