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Modélisation et simulation d'un écoulement sous vibration. Application au soudage par ultrasons de composites à matrice thermoplastique.

Abstract : Nowadays, composite materials tend to take a prominent position in the mechanical industry, especially aeronautical industry. Thermoplastic matrix composites offer a solution to reduce the long cycle time associated to thermoset matrix. New process are therefore associated to these materials. The present work focuses on the welding of thermoplastic composites. The ultrasonic welding process consists in dissipating a mechanical work at the interface. The temperature rises and induces a flow in the welding zone. The so called "continuous" process, proposed by EADS IW, may allow the assembling of aeronautical structures at an industrial scale using the ultrasonic technique. Of course, a good understanding of the process is essential before such an aeronautical application. In order to study the quality of the adhesion, the present work stands at the mesoscopic scale of few millimeters. The problematic consists in modeling and simulating numerically the thermo-mechanics of the flow at the interface during the welding process. It aims at better understanding the links between the process parameters, the physical phenomena in the welding zone, and the quality of the joining. After having identified the dominating physical phenomena, the modeling of this flow reveals the coexistence of fast (vibration) and slow (flow) phenomena. A time homogenization technique using asymptotic expansion allows to model the process with three coupled boundary value problems. The numerical solving of those problems needs specific methods in order to manage multi-physical coupling and large deformation of the geometry. Finally, the numerical tool developed allows to study the influence of different process parameters on the quality of the flow and the welding.
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Submitted on : Tuesday, June 22, 2010 - 10:20:49 AM
Last modification on : Monday, March 9, 2020 - 10:36:07 AM
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  • HAL Id : tel-00464071, version 2

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Arthur Levy. Modélisation et simulation d'un écoulement sous vibration. Application au soudage par ultrasons de composites à matrice thermoplastique.. Mécanique [physics.med-ph]. Ecole Centrale de Nantes (ECN), 2010. Français. ⟨tel-00464071v2⟩

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