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Research Associate
- Member of Clare Hall College
- Ph.D.,
Mechanical Engineering, ENS Cachan, France 2011
- MEng.,
Mechanical Engineering, ENS Cachan, France, 2008
- Agrégé de mécanique,
rank 1st, 2007
- BEng.,
Mechanical Engineering, ENS Cachan, France, 2005
Previous Positions:
- 2011-2012
Marie Curie Experienced Researcher, Mid Frequency project, University of Cambridge, UK
Research Interests:
- Electromagnetic compatibility
- Mid frequency vibro-acoustic
- Hybrid Finite Element/Statistical Energy Analysis method
- Trefftz methods
Research Group Affiliation:
Current
Project:
The aim of my new post-doctoral project is apply statistical methods to electromagnetic interference problems. Interference in electromagnetism can be defined as an electrical or magnetic disturbance that causes an undesirable response in an electronic equipment. This is an issue that arises in the transportation industry with applications to aircraft, ships or cars. All of these structures contain critical electronic equipment, which has to be protected from any peaks of current induced by an electromagnetic disturbance.Today, the use of electromagnetic shielding around wiring systems insures a degree of protection against interference, but also leads to additional weight in the structure. The goal of this project is to develop a method that could predict the mean and the variance of current inside the wiring of a structure which is subject to random electromagnetic excitations. Therefore, the structure and the electromagnetic shielding used to protect the wiring could be optimized in order to reduce the weight and improve the protection against interference. This goal will be achieved by extending the hybrid FE/SEA method from vibro-acoustics to electromagnetism of problem. The cavity will be modeled using a statistical method, whereas the wiring and the electronic equipment will be modeled using a deterministic approach.
The source may be artificial or natural, such as lighting, radio waves, a wifi router, a GSM antenna or an electromagnetic pulse.
Previous
Projects:
During my first year of postdoctoral in Cambridge, I focus on the statistical aspect of the mid- and high- frequency vibrations. Recently a hybrid finite element (FE)/statistical energy analysis (SEA) method has been developed. This method represents an efficient way of combining the strength of two well established techniques, namely FE and SEA, and allows the prediction of the ensemble mean and ensemble variance response of complex built-up structures across a broad frequency range. The key point of this method is the choice of the SEA sub-systems. During my postdoc, I develop an automatic method whereby the SEA subsystems and the master FE system in a hybrid model can be identified. This method based on a modal analysis of the system is conceptually simple and numerically efficient and stable.
I completed my PhD thesis at Ecole Normale Superieure de Cachan (one of the most prestigious french grandes ecoles), in June 2011. I worked on the VTCR, a deterministic numerical method used to solve mid-frequency vibration problems. The main feature is the use of an integral reparation of waves to described the vibrational field. My contribution to this theory has been the introduction of a new discretization of the wave amplitude based on Fourier series. It turns out that this approach exhibits similar convergence properties as the conventional approach, and improves the robustness of the method. Indeed, the Fourier based VTCR approach allows for some energy based regularization strategies, some heuristic truncation rule for a given accuracy, and finally it is easily extended to three dimensions problems.
Teaching:
- Supervision IA mechanics Homerton College
Publications of particular interest:
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L. Kovalevsky, P. Ladevèze and H. Riou, The Fourier version of the Variational theory of complex rays for medium frequency acoustics. (Computer Methods in Applied Mechanics and Engineering, Volume 225-228, 2012).
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H. Riou, P. Ladevèze, B. Sourcis, B. Faverjon and L. Kovalevsky, An adaptive numerical strategy for the medium-frequency analysis of Helmholtz's problem, (Journal of Computational Acoustic, Volume 20, Issue 1, 2012).
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P. Ladevèze, H. Riou and L. Kovalevsky, The Variational theory of complex rays for three dimensional problems in mid frequency (Journal of Sounds and Vibrations, in press).
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L. Kovalevsky, P. Ladevèze, H. Riou and M. Bonnet, The three dimensional Variational theory of complex rays for acoustic problems (Journal of Computational Acoustic, in press).
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L. Kovalevsky, H. Riou and P. Ladevèze, On the use of the Variational Theory of Complex Rays for the analysis of 2-D exterior Helmholtz problem in an unbounded domain (Wave motion, in press).
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