SMOOTH PARTICLE HYDRODYNAMICS (SPH) MODEL FOR FRICTION STIR WELDING (FSW) OF DISSIMILAR MATERIALS.

摘要

A new SPH based modeling approach for Friction Stir Welding of similar and dissimilar materials is proposed. The elastic deformations of materials are disregarded in the current model and plastic deformations are described by the Johnson-Cook model. Since its invention fifteen years ago, (FSW) has found commercial application in the marine, aerospace, rail and automotive industries. Development of the FSW process for each new application, however, has remained largely empirical. Few established numerical modeling techniques have been developed that can explain and predict important features of the process physics involved in the FSW of dissimilar materials. This is particularly true in the areas of material flow, mixing mechanisms, and void formation. In this paper we present a novel modeling approach to simulate FSW of dissimilar materials that may have significant advantages over current finite element or finite difference based methods. Unlike traditional grid-based methods, Lagrangian particle methods such as SPH can simulate the dynamics of interfaces, large material deformations, void formations and the material's strain and temperature history without employing complex tracking schemes. Two-dimensional simulations of the FSW of dissimilar materials are presented. Preliminary numerical results are in qualitative agreement with experimental observations. Detailed comparisons between experimental measurements and larger scale FSW simulations are required to further validate and calibrate the SPH based FSW model.