Damien André Email and Phone Number

The postdoc studies was conducted in the following of the phd to improve the discrete element model of silica glass grinding.

The phd work was driven by the "Commissariat à l’Énergie Atomique" (CEA) in relation with the Laser Mégajoule installation.When fused silica optics are submitted to high-power laser (such as megajoule laser or National Ignition Facility) at the wavelength of 351 nm, fused silica optics can exhibit damage, induced by the high amount of energy traversing the part. Current researches have shown that this damage could be initiated on pre-existing sub-surface damages (SSD) created during the polishing processes. The discrete element method (DEM) is proposed to simulate the polishing process and its impact on sub-surface damage creation.A summary of various studies on SSD generation during grinding processes. This work reveals certain contradictions between the theoretical models and the experimental observations. A state of the art of different numerical methods is proposed. the discrete element method (DEM) appears to be a useful tool for the study of tribological phenomena. However, the different models suggested in the literature allows quantitative descriptions. Also, a strong challenge is to develop a model providing a quantitative description and, more particularly, the mechanical properties of the silica such as elasticity and rupture.The quantitative silica model is used to simulate an abrasive methods of optical components : the fine grinding. A parametric virtual study shows good agreements with the experimental observations : the exponential decrease of the SSD number in the thickness of optical part and the influence of abrasive size particles to the maximum SSD depth.

Mechanical engineering courses for high school pupils.