Biomedical subjects

M Duquennoy

Publications and source records attributed to M Duquennoy.

3 recordsLinked to original sources

PubMed2006

Inclusions detection using Lamb waves in flexible printed circuits.

The materials used for the manufacture of flexible printed circuits are selected according to various characteristics: thermal and electrical behavior, moisture absorption, flexibility... Those are determined by the basic materials of the three components of the circuit, which are the conducting layer, the adhesive layer and the dielectric film. Such circuits have a typical thickness of about 200 microm and are therefore an interesting solution for a great number of electronic applications. However, these circuits can present various defects like inclusions, delaminations, cracks... In this work, we are interested in the detection of inclusions using guided waves propagation in such structures. These waves also called Lamb waves have the advantage of propagating over long distances while informing us about the totality of the inspected volume. According to the range of frequencies considered and the method used for their generation, it is possible to make profitable use of different propagation modes. To serve this purpose, laser-induced thermoelastic excitation of the first antisymmetric Lamb waves mode is studied. The results obtained are analysed using signal processing methods and then compared in order to clearly highlight the potentialities of these guided waves for the detection of inclusions in such samples.

Journal Article↗

PubMed2006

Ultrasonic evaluation of residual stresses in flat glass tempering by an original double interferometric detection.

In industrial thermal tempering of glass, the knowledge of the homogeneity of compressive residual stress field on the glass product is fundamental to guarantee the quality of the tempered glass product. In this paper, we use the acoustoelasticity phenomenon in order to estimate the residual stress distribution by using acoustic surface wave. We present an experimental setup based on a double interferometric detection in which an aspheric lens is associated with a beam splitter and a YAG laser whose power is 100 mW. This relative high power enables us to carry out measurements on surface flat glass although optical reflection coefficient is typically weak (< 10%). Using these two points of detection, the evolution of relative surface wave velocity is obtained with a good accuracy. At last, a comparison between the numerical modeling and experimental results shows the potentiality of an ultrasonic method to estimate stress distribution in flat glass tempering.

Algorithms↗

PubMed2005

Non-destructive testing of ceramic balls using high frequency ultrasonic resonance spectroscopy.

Although ceramic balls are used more and more for bearings in the aerospace and space industries, defects in this type of ceramic material could be dangerous, particularly if such defects are located close to the surface. In this paper, we propose a non-destructive testing method for silicon nitride balls, based on ultrasonic resonance spectroscopy. Through the theoretical study of their elastic vibrations, it is possible to characterize the balls using a vibration mode that is similar to surface wave propagation. The proposed methodology can both excite spheroidal vibrations in the ceramic balls and detect such vibrations over a large frequency range. Studying their resonance spectrums allows the balls' elastic parameters be characterized. Ours is an original method that can quickly estimate the velocity of surface waves using high frequency resonances, which permits surface and sub-surface areas to be tested specifically. Two applications are described in this paper. Both use velocity measurements to achieve their different goals, the first to differentiate between flawless balls from different manufacturing processes, and the second to detect small defects, such as cracks. Our method is rapid and permits the entire ceramic ball to be tested in an industrial context.

Ceramics↗