Jean-Christophe Roux

A simple and robust moving mesh technique for the finite element simulation of Friction Stir Welding

The simulation of the Friction Stir Welding process is a complex problem which involves physical couplings between mechanics and heat transfer, very large deformations and strain rates in the stirring zone around the pin. To avoid mesh distortions or very large computing time due to the Arbitrary Lagrangian Eulerian technique usually proposed in the literature for the finite element method, a simple but robust moving mesh technique is proposed for the numerical modeling of the FSW process. It is based on a Eulerian formalism and the mesh is composed of 2 parts: a first one which is fixed around the stirring zone and a second one which includes the base material near the tool and moves with a rotational solid motion corresponding to the tools velocity. Therefore, there are no mesh distortions and the Eulerian formalism leads to satisfying computing time. An example clearly evidences the efficiency and robustness of the moving mesh technique proposed for a 3D complex geometry of the tool.

Vibrations and stresses in band saws: A review of literature for application to the case of aluminium-cutting high-speed band saws

Abstract The development of band saws for the cutting of aluminium plates has been growing up during the last 15 years. This technology faces several difficulties regarding blade vibrations and blade lifetime. Concerning the band sawing process, all the research works published up to now are dealing with wood-cutting. In this paper, a review of the most important literature published on the subjects of band saw vibrations and stresses into blades is presented with a special attention to the latest research developments. The application of this state-of-the-art to the case of aluminium-cutting using modern high-speed band saws is discussed and interesting research directions are highlighted.

Theoretical Framework of a Variational Formulation for Nonlinear Heat Transfer with Phase Changes

This paper discusses mathematical results for a variational formulation dedicated to heat transfer with phase changes. Practical finite element experiences show that the studied formulation can lead to difficulties for the numerical resolution at each time step. The aim of the paper is to show that such numerical pathologies do not come from the basic variational formulation by showing existence and uniqueness of the solution.