Research on Material Science

FE modelling of woven fibre of composite materials

The forming simulation of woven reinforcements allows access to information such as the fibre positions after forming, but also the deformation state, as well as the prediction of defects such as wrinkles, yarn sliding and fibre/yarn fracture. The proposed model consists of a mesoscopic description of the reinforcement. It is simple enough to render the simulation of the forming preform possible but describes also properly the main phenomena occurring during the forming. A geometrical model is proposed, where each yarn is modelled using shell elements in contact-friction with its neighbours. A hypoelastic description is used, specific for the yarn behaviour. Identification and validation of the model are done using standard characterisation tests for fabrics. Forming simulations illustrate the capabilities of the proposed approach. A main interest of such modelling is the possibility for the simulation to exhibit large sliding between warp and weft yarns when the tensile loads are too important. 

Porous ceramic microstructural shaping by freeze casting

tomographic reconstruction of the freezing front dynamics in alumina colloidal solution

Ice templating of colloidal suspension is gaining interest in material science because it offers the possibility to shape advanced materials, in particular porous ceramics. Recent investigations on this process show that a correlation between the morphology of the frozen suspension and the velocity of the freezing front do exist. The dynamics of the freezing front of a colloidal suspension of alumina is investigated in this study by experimental tests, finite element analysis, and analytical calculations. The experimental tests are carried out by in situ X-ray radiography (dynamics of the freezing front) and tomography (morphology of the frozen suspension). The finite element model is a continuous properties model; it is used for investigating the dynamics and the shape of the freezing front.

Analysis of damage in metallic materials by X-ray tomography

In situ tensile test coupled with X-ray tomography is a powerful tool for 3D reconstruction and non destructive observations of microstructure and damage of materials, in particular for the comprehension of nucleation, growth and coalescence of voids in metal alloys. A set of tests has been carried out on dual-phase steel, ferrite and martensite, at different in order to compare the performance of different materials. Qualitative and quantitative analysis of the damage events were carried out at each deformation step, on the same 3D region in the reconstructed volumes. This technology allow a deep insight into the material behaviour and provide experimental support to damage analysis, previously carried out by SEM and optical microscopy. The 3D reconstruction also provide the chance for built an accurate geometry for FE analysis.

Publications & Papers on Material Science

S. Gatouillat, A. Bareggi, E. Vidal-Sallé, P. Boisse, Meso modelling for composite preform shaping – Simulation of the loss of cohesion of the woven fibre network, Composites Part A, Volume 54, November 2013, Pages 135–144. Download

A. Bareggi, E. Maire, O. Bouaziz, M. Di Michiel, Damage in dual phase steels and its constituents studied by X-ray tomography, Int. J. Fracture, April 2012, Volume 174, Issue 2, pp 217-227. Download

A. Bareggi, E. Maire, A. Lasalle, S. Deville, Dynamics of the Freezing Front During the Solidification of a Colloidal Alumina Aqueous Suspension: In Situ X-Ray Radiography, Tomography, and Modeling, J. American Ceramic Society, Volume 94, Issue 10, pages 3570–3578, October 2011, Download