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Saint-Étienne, France

Onder O.,Joseph Fourier University | Paris H.,Joseph Fourier University | Rech J.,LTDS
Mechanics and Industry

In industrial area, drilling is one of the most commonly used machining operations. Today, conventional drilling methods have found their limits in deep hole drilling. To be able to push these limits, we have developed a new technology: vibratory drilling. The aim of this study is to determine the influence of the twist drill geometry on performance of the self vibratory drilling head. For that reason, it is necessary to identify the geometrical properties which have the strongest influence on axial vibrations of twist drill and on chip fragmentation. Moreover, we have also validated the experimental results by a simulator which can predict the behaviour of the self vibratory drilling head by taking into account geometrical defects of the tool. © AFM, EDP Sciences 2012. Source

Jolivet S.,Arts et Metiers ParisTech | Mezghani S.,Arts et Metiers ParisTech | Isselin J.,Arts et Metiers ParisTech | Giraudeau A.,Arts et Metiers ParisTech | And 2 more authors.
Key Engineering Materials

For automotive gear manufacturers, reducing gear noise while maintaining the gear load-carrying capacity as well as the wear resistance has become more and more important. Macro- and micro-geometrical defects have long been studied in order to explain the vibratory behavior of gears. However, the contribution of the micro-scale roughness of the flanks, essential in the gear contact mechanics, has not yet been fully understood. This paper addresses this issue where gears were manufactured with two industrial finishing processes (grinding and power-honing) while having the same macro-scale characteristics. Tridimensional topographical features of teeth surface were hence measured using a three-dimensional white light interferometer. As manufactured surface topographies are highly complex, irregular, and multiscale, all the teeth surfaces were characterized in the entire wavelength band using a multiscale method based on wavelets transform. Vibration performances of the gears were then tested on a single-stage low powertrain. Results demonstrate the influence of micro-roughness scales on vibrations amplitude. © (2015) Trans Tech Publications, Switzerland. Source

Canales D.,Ecole Centrale Nantes | Cueto E.,University of Zaragoza | Feulvarch E.,LTDS | Chinesta F.,Ecole Centrale Nantes
Key Engineering Materials

Friction Stir Welding (FSW) is a welding technique more and more demanded in industry by its multiple advantages. Despite its wide use, its physical foundations and the effect of the process parameters have not been fully elucidated. Numerical simulations are a powerful tool to achieve a greater understanding in the physics of the problem. Although several approaches can be found in the literature for simulating FSW, all of them present different limitations that restrict their applicability in industrial applications. This paper presents a new solution strategy that combines a robust approximation method, based on natural neighborhood interpolation, with a solution separated representation making use of the Proper Generalized Decomposition (PGD), for creating a new 3D updated-Lagrangian strategy for addressing the 3D model while keeping a 2D computational complexity. © 2014 Trans Tech Publications, Switzerland. Source

Tateo F.,FEMTO ST Institute | Collet M.,FEMTO ST Institute | Ouisse M.,FEMTO ST Institute | Ichchou M.N.,LTDS
Proceedings of SPIE - The International Society for Optical Engineering

A recent technological revolution in the fields of integrated MEMS has finally rendered possible the mechanical integration of active smart materials, electronics and power supply systems for the next generation of smart composite structures. Using a bi-dimensional array of electromechanical transducers, composed by piezo-patches connected to a synthetic negative capacitance, it is possible to modify the dynamics of the underlying structure. In this study, we present an application of the Floquet-Bloch theorem for vibroacoustic power flow optimization, by means of distributed shunted piezoelectric material. In the context of periodically distributed damped 2D mechanical systems, this numerical approach allows one to compute the multi-modal waves dispersion curves into the entire first Brillouin zone. This approach also permits optimization of the piezoelectric shunting electrical impedance, which controls energy diffusion into the proposed semi-active distributed set of cells. Furthermore, we present experimental evidence that proves the effectiveness of the proposed control method. The experiment requires a rectangular metallic plate equipped with seventy-five piezo-patches, controlled independently by electronic circuits. More specifically, the out-of-plane displacements and the averaged kinetic energy of the controlled plate are compared in two different cases (open-circuit and controlled circuit). The resulting data clearly show how this proposed technique is able to damp and selectively reflect the incident waves. © 2013 SPIE. Source

Canales D.,Ecole Centrale Nantes | Leygue A.,Ecole Centrale Nantes | Chinesta F.,Ecole Centrale Nantes | Cueto E.,University of Zaragoza | And 4 more authors.
Key Engineering Materials

A new efficient updated-Lagrangian strategy for numerical simulations of material forming processes is presented in this work. The basic ingredients are the in-plane-out-of-plane PGD-based decomposition and the use of a robust numerical integration technique (the Stabilized Conforming Nodal Integration). This strategy is of general purpose, although it is especially well suited for plate-shape geometries. This paper is devoted to show the feasibility of the technique through some simple numerical examples. © (2015) Trans Tech Publications, Switzerland. Source

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