A Mesh-Free Solid-Mechanics Approach for Simulating the Friction Stir-Welding Process

Abstract

In this chapter, we describe the development of a new approach to simulate the friction stir-welding FSW process using a solid-mechanics formulation of a mesh-free Lagrangian method called smoothed particle hydrodynamics SPH . "lthough this type of a numerical model typically requires long calculation times, we have developed a very efficient parallelization strategy on the graphics processing unit GPU . This simulation approach allows the determination of temperature evolution, elastic and plastic deformation, defect formation, residual stresses, and material flow all within the same model. More importantly, the large plastic deformation and material mixing common to FSW are well captured by the mesh-free method. The parallel strategy on the GPU provides a means to obtain meaningful simulation results within hours as opposed to many days or even weeks with conventional FSW simulation codes.

Defect formation and material flow in Friction Stir Welding

“…Both studies overestimated the void size. Fraser et al [30] used a mesh-free Lagrangian SPH method to simulate the FSW process. Their model could predict free surface changes and flash formation.…”

Prediction of joint line remnant defect in friction stir welding

“…Computationally, the joint line remnant defect due to oxide layer evolution during the weld has not been investigated in detail so far. However, numerical modelling has been used to study imperfections such as free surface changes (Fraser et al [14]), void (Zhu et al [15] and Al-Badour et al [16]), tunnel-like (Atharifar et al [17] and Shinoda and Kondo [18]) and wormhole (Zhu et al [19]). Numerical methods enable a fast determination of the process parameters for experimental implementation.…”

Optimization of Friction Stir Weld Joint Quality Using a Meshfree Fully-Coupled Thermo-Mechanics Approach

“…A summary of the supporting equations and the associated nomenclature is provided in Tables 2 and 3. Full details of the field equations and their SPH formulation can be found in [34,36,37,[40][41][42][43]. Table 1.…”

“…Some of the more popular meshfree methods are the local radial point interpolation method (LRPIM) [28,29], meshless local Petrov-Galerkin (MLPG) [30], finite point method (FPM) [31], as well as the smoothed particle hydrodynamics method (SPH) [32,33]. Fraser et al [34][35][36][37][38][39][40][41][42][43] have recently developed an advanced meshfree framework on the graphics-processing unit (GPU) to simulate the entire FSW process. Their code-SPHriction-3D-is able to predict temperature, process forces/torques, internal and surface defects, tool wear, and residual stresses.…”