Downloads

Other information

Associations : Funder of Solar Impulse (Si2 project), Sponsor of "Un toit pour les abeilles", Member of SFA, Member of RAmDAM

Hobbies : Karate (1st Dan), Music, Science, Books, Handywork

Downloads

Subject

In order to decrease energy consumptions, transportation industries are progressively focusing on composite materials because of their important stiffness to mass ratio. Nonetheless their use is generally relegated to secondary elements (car's bonnet, inner parts, plane's tail...) since the dynamic behaviour of composite structures is not fully understood so far. Novel methods are then necessary to identify elastic properties of these new structures but also to detect potential flaws.

This PhD thesis dealt with the "Characterization of composite materials using an inverse vibratory method" using the Force Analysis Technique and was directed by Charles Pézerat, Jean-Louis Guyader and Frédéric Ablitzer.

General Principle

The goal is to develop a new approach for estimating elastic parameters (Young's Modulus E, shear modulus G and their respective loss factors ηE and ηG) of composite materials. Since these structures usually present specific vibratory behaviours, classical methods like modal theory, 3 points flexural tests or the Oberst method can provide wrong identifications.

Instead of analysing each layer independently (first plausible source of bias) in order to model a realistic multi-layer structure in a Finite Element simulation or analytical formulation (second possible source of bias), an original experimental approach is suggested based on the local verification of the equation of motion applied to the Timoshenko beam combined with the inverse vibratory method called the Force Analysis Technique. By doing so the experimental part only consists in measuring the transverse displacement field.

This novel approach then considers the composite material as an homogeneous one, leading to the determination of equivalent elastic parameters. Since the method relies on a local identification, it does not depend on the boundary conditions, its application is simple and allows developments for structural health monitoring or implemented analysis on a production line.

An extension to flaw detection is also of interest because the kind of defect may be identified through the cartographies of elastic parameters. For instance a fibre breakage could change only the Young's modulus, a delamination might mostly influence the shear modulus, while a Barely Visible Impact Damage would increase local dissipation and so the damping coefficients.

References

T.Wassereau, F.Ablitzer, C.Pézerat, J-L.Guyader. Experimental identification of flexural and shear complex moduli by inverting the Timoshenko beam problem. Journal of Sound and Vibration, 399 : pp 86-103 (2017). DOI:10.1016/j.jsv.2017.03.017

F. Ablitzer, C. Pézerat, J.-M. Génevaux, J. Bégué. Identification of stiffness and damping properties of plates by using the local equation of motion. Journal of Sound and Vibration, 333 (9) : pp.2454–2468 (2014). DOI : 10.1016/j.jsv.2013.12.013

C. Pézerat, J.-L. Guyader. Two inverse methods for localization of external sources exciting a beam. Acta Acustica, 3 : pp. 1–10 (1995).

J.-L. Guyader, C. Cacciolati, E. Guyader. Prediction of vibroacoustic behaviour of multilayered structures using equivalent bi-materials. In Inter-noise. Shangai, China (2008).

Partnership

Articles

T.Wassereau, F.Ablitzer, C.Pézerat, J-L.Guyader. Experimental identification of flexural and shear complex moduli by inverting the Timoshenko beam problem. Journal of Sound and Vibration, 399 : pp 86-103 (2017). DOI:10.1016/j.jsv.2017.03.017

G.Penelet, M.Leclercq, T.Wassereau, P.Picart. Measurement of density fluctuations using digital holographic interferometry in a standing wave thermoacoustic oscillator. Experimental Thermal and Fluid Science, 70 : pp.176-184 (2016). DOI : 10.1016/j.expthermflusci.2015.09.012

Conferences

T.Wassereau. C.Pézerat, J-L.Guyader, F.Ablitzer. Caractérisation de défauts sur matériaux composites par résolution et régularisation du problème inverse vibratoire. CFA 2016, Le Mans (France)

B. Lascoup, T.Wassereau, F. Ablitzer, C.Pézerat. Identification des propriétés mécaniques d’un composite par méthode RIFF. JNC 2015, Lyon (France)

T.Wassereau. C.Pézerat, J-L.Guyader, F.Ablitzer. Improvements of force analysis technique for flaw detection on composite materials. DynComp 2015, Arles (France).

T.Wassereau. C.Pézerat, J-L.Guyader, F.Ablitzer. Characterization of composite materials and flaw detection using Force Analysis Technique. NOVEM 2015, Dubrovnik (Croatia).

P.Picart, G.Penelet, M.Leclercq, I.Kostyrko, T.Wassereau. Analyse du déclenchement d'un moteur thermoacoustique par interférométrie holographie multi-échelle. Holo Phy 3, Ecully (France).

T.Wassereau, C.Pézerat, J-L.Guyader, F.Ablitzer. Caractérisation de matériaux composites par problème inverse vibratoire. CILSA 2014, Lyon (France).

G.Penelet, M.Leclercq, T.Wassereau, P.Picart. Mesure de champs acoustiques par holographie optique numérique : Application à la thermoacoustique. CFA 2014, Poitiers (France).

P.Picart, M.Leclercq, T.Wassereau, G.Penelet. Multi-scale digital holographic interferometry for studying a thermoacoustic resonator. Digital Holography and Three-Dimensional Imaging 2014, Seattle (USA).

Poster Sessions

T.Wassereau, C.Pézerat, J-L.Guyader, F.Ablitzer. Identification de paramètres élastiques homogénéisés d’un matériau multicouches par méthode RIFF. JJCAB 2015, Besançon (France)

T.Wassereau, C.Pézerat, J-L.Guyader, F.Ablitzer. Détection de défauts sur poutre composite par Résolution Inverse Filtrée Fenêtrée. JJCAB 2014, Lyon (France).

• Show All
• Thermoacoustics / Holography
• Granular avalanche
• Hidden cracks
• Acoustics softwares
• SAdB Design office
• Tuning fork
• General Electric
• Tubular bells