[Soutenance de thèse] Soutenance de thèse C. Fougerouse - 20 mars 2023

[Soutenance de thèse] Soutenance de thèse C. Fougerouse - 20 mars 2023
Lundi 20 mars 2023
Onera Palaiseau, salle Marcel Pierre: 6, chemin de la Vauve aux Granges, 91123 Palaiseau.

La soutenance de thèse de Claire Fougerouse, thèse CIFRE Airbus Opération effectuée au sein de l'école doctorale SMEMAG de l'université Paris-Saclay intitulée "Understanding and modelling of the effects of out-of-plane waviness defects on the mechanical performance of a thermoplastic matrix laminate" aura lieu le lundi 20 mars 2023 à 14H dans la salle Marcel Pierre de l'Onera Palaiseau: 6, chemin de la Vauve aux Granges, 91123 Palaiseau.

 

Le jury sera composé :

Zoheir ABOURA,                     UTC Compiègne                   Rapporteur
Christophe BOUVET,               ISEA-SUPAERO Toulouse    Rapporteur
Jean-Claude GRANDIDIER,    ISAE-ENSMA Poitiers           Examinateur
Michael WISNOM,                   University of Bristol                Examinateur
Christian FAGIANO,                ONERA/DMAS                       Encadrant
Martin HIRSEKORN,               ONERA/DMAS                       Encadrant
Frédéric LAURIN,                    ONERA/DMAS                       Directeur de thèse
Martin DESAILLOUD,              AIRBUS Operations               Invité

 

Résumé :

This Ph.D. thesis (CIFRE ONERA with funding from AIRBUS Operations) focuses on the out-of-plane waviness manufacturing defect generated in specimens of composite laminates composed of unidirectional plies with carbon fibres and a thermo-plastic matrix. The effects of the defects on the mechanical performance were studied for tensile and compressive loads.
Out-of-plane waviness was artificially generated in the specimens during the manufacturing process. Optical observations on the specimen edge were carried out prior to the tests to analyse the defect morphologies. An experimental campaign on specimens with and without defects was carried out with multi-instrumented tests. It revealed a stiffness decrease, differences in damage scenarios (notably earlier crack and delamination initiation) and a failure stress reduction in the presence of a waviness.
In parallel, finite element models were developed to refine the understanding of the effects of defects. For this purpose, a digital twin was generated for each specimen based on optical microscope observations of the defect geometry carried out before the tests and on the basis of a parametric description of the defect. With a continuous damage model, the simulations revealed a local reduction of the elastic properties close to the maximum waviness and a significant knock down on the failure stress in relation to the severity of the defect. The model qualitatively captured the damage scenario of the experiments. Finally, a numerical strategy based on metamodelling was proposed to analyse the influence of each geometrical parameter of the defect on the mechanical response and to propose a fast estimate of the defect-induced knock down factors according to its geometry.
 

Mots clés :

Thermoplastic matrix laminate, effects of manufacturing defects, experiment-modelling comparison

 

Accès à la soutenance :

Pour accéder aux locaux de l'Onera, il faut impérativement que vous fassiez parvenir une photocopie de votre carte d'identité le plus rapidement possible (au plus tard le mercredi 15 mars 17H à frederic.laurin@onera.fr). De plus, le jour de la soutenance, il faudra fournir à l'accueil votre pièce d'identité pour accéder à la salle.

Il est également possible d'assister à la soutenance par visio-conférence. Le lien vous sera envoyé suite à un email envoyé à frederic.laurin@onera.fr.

 

    Cordialement,

        Frédéric Laurin, Christian Fagiano, Martin Hirsekorn