A Comparison of Different Finite Element Methods in the Thermal Analysis of Friction Stir Welding (FSW)

Abstract

Friction Stir Welding (FSW) is a novel kind of welding for joining metals that are impossible or difficult to weld by conventional methods. Three-dimensional nature of FSW makes the experimental investigation more complex. Moreover, experimental observations are often costly and time consuming, and usually there is an inaccuracy in measuring the data during experimental tests. Thus, Finite Element Methods (FEMs) has been employed to overcome the complexity, to increase the accuracy and also to reduce costs. It should be noted that, due to the presence of large deformations of the material during FSW, strong distortions of mesh might be happened in the numerical simulation. Therefore, one of the most significant considerations during the process simulation is the selection of the best numerical approach. It must be mentioned that; the numerical approach selection determines the relationship between the finite grid (mesh) and deforming continuum of computing zones. Also, numerical approach determines the ability of the model to overcome large distortions of mesh and provides an accurate resolution of boundaries and interfaces. There are different descriptions for the algorithms of continuum mechanics include Lagrangian and Eulerian. Moreover, by combining the above-mentioned methods, an Arbitrary Lagrangian-Eulerian (ALE) approach is proposed. In this paper, a comparison between different numerical approaches for thermal analysis of FSW at both local and global scales is reviewed and the applications of each method in the FSW process is discussed in detail. Observations showed that, Lagrangian method is usually used for modelling thermal behavior in the whole structure area, while Eulerian approach is seldom employed for modelling of the thermal behavior, and it is usually employed for modelling the material flow. Additionally, for modelling of the heat affected zone, ALE approach is found to be as an appropriate approach. Finally, several significant challenges and subjects remain to be addressed about FSW thermal analysis and opportunities for the future work are proposed.

Finite element modeling of nano porous sintered silver material using computed tomography images

“…The second phase however, shows a linear pattern. The same contour pattern for the stress-strain curve was also obtain in the literature which show a good agreement between the results of this study and the literature [17].…”

“…Higher deformation counter also observed in sample 1 due to the lower pore space in the model. The observed deformation in the literature is lower, because the thickness of the samples in the literature is more than the thickness of the specimens employed in this research [17]. Moreover, higher deformation in the horizontal axis was observed in the sample 1.…”

“…Results also were compared with the literature where the stress was observed to be around 44 MPa. Moreover, the same deformation pattern was obtained from the literature [17,18].…”

A comparison between temperature dependent and constant Young's modulus values in investigating the effect of the process parameters on thermal behaviour during friction stir welding

“…As a function of temperature, the friction coefficient values in a variety of 0.207089 to 0.00058 are applied to the model [15,16]. Past studies claimed that, the welding rotational and transverse velocities affect the heat generation during process [1,[17][18][19]. The results of the paper indicated that the model in which the temperature dependent Young's modulus values are applied is more accurate.…”

“…As the tool plunges into the plates (while it is rotating) and moves along the welding seam, friction stir welding (FSW) will be created, Figure 1 [1]. Fundamentally, because of the large plastic deformation and the complicated frictional phenomena thermal and mechanical behaviors of friction stir welding are highly complex.…”