Pole EPI

Senlis, France
Senlis, France
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Dahmene F.,CNRS Roberval Laboratory (Mechanical Research Unit) | Dahmene F.,Ecole Des Mines de Douai | Laksimi A.,CNRS Roberval Laboratory (Mechanical Research Unit) | Hariri S.,Ecole Des Mines de Douai | And 4 more authors.
International Journal of Pressure Vessels and Piping | Year: 2012

Prior to the detection and monitoring by acoustic emission of defects in steel, this paper deals with the use of waveguide that avoids direct contact between the sensor and monitoring structure when working at high temperature. The study of the waveguide effect on elastic wave transmission shows that waveguide deforms the waveform but it does not affect its frequency. Waveguide length does not affect signal magnitude. An experimental example of compact tensile specimen monitoring by acoustic emission is given. The monitoring of the damage at low and high temperature "450 °C" by acoustic emission enables us to identify crack propagation stages and their acoustic signature. © 2012 Elsevier Ltd.


Terrien N.,Pole EPI | Dhamene F.,ECW | Zejli H.,ALTEN | Habti M.D.,PRES LUNAM
7th European Workshop on Structural Health Monitoring, EWSHM 2014 - 2nd European Conference of the Prognostics and Health Management (PHM) Society | Year: 2014

This paper is dealing with the development of a structural health monitoring (SHM) system implemented on a composite footbridge during the regional project "Pays de la Loire" called DECID2. The SHM system was made out of complementary techniques: strain sensors based on optical fibers (out of concern in this present work) and ultrasonic techniques that are presented in this document. Due to the huge size of the composite bridge (20 m ∗ 3 m), only its most critical areas are monitored as the assembling parts and the most solicited areas. To access the structural integrity of the footbridge, two complementary monitoring strategies were presented in this paper: - a real-time acoustic emission monitoring system to detect fibre breaks, - and a monitoring system using guided waves to evaluate the resin degradation. Both of these SHM systems use the same miniature ultrasonic patches that are used alternately as acoustic emission sensors and as ultrasonic guided waves actuators. The first step of this work was to develop these patches, and then to set up each monitoring systems and characterize their damage sensitivity. Finally, two composite footbridges were built at the EMC2 Technocampus and IFSTTAR in France to serve as demonstrators. Copyright © Inria (2014).

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