Statement of Research Interests Abderrazak Traidia Research Area Today, most of the industrial and scientific issues in engineering combines several physics; heat flows, fluid flows, chemical diffusions, electromagnetic effects, metallurgical and mechanical states, etc. My primary research interest is in the area of modeling multiphysics couplings in mechanical engineering. Specifically, I work on the modeling and numerical simulation of arc welding in the assembly of nuclear power plants components. My general research question is how the numerical simulation of manufacturing processes can support engineers toward a sustainable design of products in energy, transportation, and biomedical applications.
Current Research and Approach For my PhD, I am developing mathematical models for the numerical simulation of Gas Tungsten Arc Welding. This joining process is often used by manufacturing industries that require high quality assemblies, and more particularly in the oil & gas and nuclear industries to guaranty the safety of installations. My research work is funded by AREVA Nuclear Products Company. First, based on a muliphysics approach a three dimensional Magneto-Hydro-Dynamic (MHD) formulation is used to couple electromagnetic effects (due to the current flow), thermal effects (heating of the arc plasma and the workpiece), and the fluid dynamics (shielding gas and molten metal flows). The strongly coupled equations are solved using the finite element method. Calculations are performed in parallel mode to study the effect of various governing forces such as gravity, buoyancy, surface tension and electromagnetic field on the weld pool time evolution [1, 2, and 5]. The model is also used to study the effect of the shielding gas composition on the improvement of GTA welding. The alternate addition of Helium gas in the weld zone is found to have advantageous effects on the weld pool dynamics and leads to an important increase in the weld depth and the weld quality [3]. In addition I am also working on the coupling between the previous MHD formulation with non linear solid mechanics equations. This comprehensive model permits to predict the residual stresses and metallurgical transformations near the weld, so as to quantify the welded joint quality [4]. The aim of this multiphysics approach is to have a direct link between the operating welding parameters and the mechanical and metallurgical consequences induced by the welding operation [6]. Finally, I applied my developed model for an industrial application: the simulation of Narrow Gap welding with gravity effect. This technique is used for the assembly of thick pipes is both oil & gas and nuclear manufacturing. The numerical results permitted to understand the origin of several defects around the weld usually observed by AREVA NP engineers. My
developed model will be used in the near future to find the parameters that minimize these defects.
Future Research Directions On one hand energy is becoming the most precious resource of upcoming decades; on the other hand uncontrolled usage of energy is causing environmental disasters threatening the very survival of human species. My vision is that a sustainable design of structures can be leveraged to develop energy efficient products. On the foundations of my PhD and my strong skills in Solid Mechanics and Computational Fluid Dynamics, I intend to work (but is not limited to) on the study of new sustainable manufacturing processes for energy, transportation, and biomedical applications. Among others, I am specifically interested in the use of optimization tools for the improvement of manufacturing processes. Highly motivated by performing collaborative research and providing supports in multiple research projects, I am also very interested in industrial and scientific challenges that deal with complex and strongly coupled multiphysics phenomena. I believe that my proven theoretical analysis capability, practical software use and implementation skills, as well as my industry collaboration experience will undoubtedly be helpful to be a passionate team player, and make active contributions.
Selected Peer-Reviewed Papers 1. A.Traidia, F.Roger, E.Guyot. Optimal parameters for pulsed gas tungsten arc welding in partially and fully penetrated weld pools. 2010. International Journal of Thermal Sciences. 49:1197-1208. 2. [Accepted to appear] A.Traidia, F.Roger. Numerical and experimental study of arc and weld pool behavior for pulsed GTA welding. 2010. International Journal of Heat and Mass Transfer. 3. [Submitted] A.Traidia, F.Roger. A computational investigation of different helium supplying methods for the improvement of GTA welding. 2010. Journal of Materials Processing Technology. 4. [Submitted] A.Traidia, F.Roger. Metallurgical transformations in 16MnD5 steel during pulsed and continuous GTA welding: a multiphysics approach. 2011. Metallurgical and Materials Transactions B. 5. [Preparation] A.Traidia, F.Roger, J. Schroeder. Heat transfer and fluid flow in moving Gas Tungsten Arc Welding: a hybrid 2D-3D model. 2011. 6. [Preparation] A.Traidia, F.Roger. A comprehensive multiphysics approach for the determination of residual stresses in arc welding. 2011.
