Numerical modeling of welded joints by the "Friction Stir Welding" process

Abstract

The present work is aimed to simulate the Friction Stir Welding process as a three-dimensional thermally coupled viscoplastic flow. A Finite Element technique is employed, within the context of a general purpose FEM framework, to provide the temperature distributions and the patterns of plastic flow for the material involved in the welded joints. The computational tool presented here may be of great relevance for technologist seeking to set the process control variables, as they are intended to obtain suitable material properties that yield the adequate on service response of the structural components

Numerical modeling of friction stir welding process: a literature review

“…The heat generated during the welding process is equivalent to the power input introduced into the weld by the tool minus some losses due to microstructural effects [21]. The peripheral speed of the shoulder and probe is much higher than the translational speed (the tool rotates at high speeds).…”

“…Simar et al introduce a parameter ( γ ) that exposes the relative importance of both contributions [32]: (21) where V Q is the volume heat contribution and S Q is the total tool surface heat contribution. For thermal computational models which take into account the material fluid flow, Simar et al…”

“…The power spent in the translation movement, which is approximately 1% of the total value, is typically neglected in the total heat input estimative [11,30]. Therefore, the power introduced by the tool (input power P ) can be obtained experimentally from the weld moment and angular rotation speed [21,32]: η QP (23) where η is the fraction of power generated by the tool that is directly converted into heat in the weld material. Nandan et al refer to this as the power efficiency factor [33].…”

3D modeling of material flow and temperature in Friction Stir Welding

“…These analyses are based on a heat source model, not considering the thermo-mechanical coupling generated by plastic flow. It is worth mentioning that due to the characteristics of this problem, by using fully coupled thermal-mechanical viscoplastic flow models [11][12][13], good results can be expected where plastic deformations commonly occur. Besides, due to its geometric and kinematic characteristics, the problem is mainly threedimensional, which together with the presence of high strain rate gradients around the probe imposes a high computational demand.…”

Modelado numérico del proceso de soldadura por fricción agitación en aceros inoxidables

“…Estos análisis se basan en un modelo de fuente de calor, sin contemplar el acoplamiento termomecánico provocado por el flujo plástico. Es de destacar que por las características del problema, donde las deformaciones plásticas son dominantes, pueden lograrse buenos resultados empleando modelos de flujo viscoplástico termomecánicamente acoplados (Ulysse [5]; Santiago et al [6,7]; Colegrove et al [8]). …”