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Le Touquet – Paris-Plage, France

Liang S.,University of Burgundy | Gning P.B.,University of Burgundy | Guillaumat L.,ENSAM
Composites Science and Technology | Year: 2012

Experimental investigations on flax and glass fabrics reinforced epoxy specimens, i.e. FFRE and GFRE, submitted to fatigue tests are presented in this paper. Samples having [0/90] 3S and [±45] 3S stacking sequences, with similar fibre volume fractions have been tested under tension-tension fatigue loading. The specific stress-number of cycles to failure (S-N) curves, show that for the [0/90] 3S specimens, FFRE have lower fatigue endurance than GFRE, but the [±45] 3S FFRE specimens offer better specific fatigue endurance than similar GFRE, in the studied life range (<2×10 6). Overall, the three-stage stiffness degradation is observed in all cases except for [0/90] 3S FFRE specimens, which present a stiffening phenomenon of around 2-3% which could be related to the straightening of the microfibrils. © 2012 Elsevier Ltd. Source

Makhoul N.,ENSAM
Large Structures and Infrastructures for Environmentally Constrained and Urbanised Areas | Year: 2010

The extra cost of the measures taken to protect a building against seismic risk is higher concerning old buildings than new designed ones. But since more than 80% of buildings were designed before the new seismic codes, it is a huge heritage waiting to manage, with great priority. Sophisticated methodologies are emerging in Seismic Engineering, as the Performance Based Earthquake Engineering, PEER. We improved the decision analysis model, and we proposed a multidisciplinary approach dealing with different classes of buildings and different seismic regions to solve, without restriction, the particular case of France. It allows sharing the responsibility by all, in order to convince people to rehabilitate their structures by including them in the decision process. Source

Gournay P.,French National Laboratory of Metrology and Testing | Thevenot O.,French National Laboratory of Metrology and Testing | Dupont L.,French National Laboratory of Metrology and Testing | David J.M.,ENSAM | Piquemal F.,French National Laboratory of Metrology and Testing
Canadian Journal of Physics | Year: 2011

This paper reports on the current development of a new Thompson-Lampard calculable capacitor at LNE. The goal is to determine the von Klitzing constant R K at a significant level of uncertainty of about one part in 10 8. The comparison with other accurate measurements of h/e2 serves as a relevant test of validity of the theory predicting R K = h/e 2, a decisive issue within the context of the new SI. Conversely, assuming that this relation is exact, the measurement of R K and thus that of the fine structure constant can be used for testing quantum electrodynamics theory. The mechanical structure of the new LNE calculable cross capacitor has been designed and a new set of electrodes has been fabricated. The assembling of the calculable capacitor is in progress. Source

Thomas M.,ONERA | Malot T.,ENSAM | Aubry P.,CEA Saclay Nuclear Research Center | Colin C.,MINES ParisTech | And 2 more authors.
Materials at High Temperatures | Year: 2016

This paper deals with the prospects for additive manufacturing (AM) of bulk TiAl alloys. A number of AM processes have already been explored in the literature for these intermetallic alloys. The main trend developed in published works concerns a strong crack sensitivity of this relatively brittle material due to rapid successive heating and cooling cycles. Optimised processing conditions have already been achieved for producing sound and crack-free TiAl materials by means of EBM and laser metal deposition processes. This experimental work was particularly focused on the third process, i.e. selective laser melting, to produce fully dense TiAl parts. A series of beads, surface layers and cubes have been manufactured to investigate the microstructural evolution. Post-heat treatments allowed a uniform microstructure to be restored for the intermetallic TiAl alloy. © 2016 Informa UK Limited, trading as Taylor & Francis Group. Source

Bouanani F.E.,Mohammed V University | Ben-Azza H.,ENSAM | Belkasmi M.,Mohammed V University
Eurasip Journal on Wireless Communications and Networking | Year: 2012

In this article, we investigate the Shannon capacity for L-branch maximal combining ratio (MRC) over generalized multipath fading channel. We derive closed-form expressions of the maximal spectral efficiency over Rayleigh, Rician, Nakagami-m, and Weibull multipath fading channel under flat fading conditions. The results are expressed in terms of Meijer G-functions, which can be evaluated numerically using mathematical tools such as Mathematica and Maple. We show, in particular, that the more the number L increases, the larger the Shannon capacity is. We deduce that four branches are sufficient in several cases to mitigate the fading effect and the channel model will approaches the one of AWGN. © 2012 El Bouanani et al.; licensee Springer. Source

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