Characterization of damage in laminated composite materials using displacement measurements obtained by a full-field optical method

• Main Author: Farge, Laurent
• Other Authors: Institut Jean Lamour (IJL), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Institut National Polytechnique de Lorraine, Zoubir Ayadi
• Format: Doctoral or Postdoctoral Thesis
• Language: French
• Published: HAL CCSD 2009
• Subjects: Laminates; Speckle Interferometry; Intralaminar Cracks; Damage; Stratifiés; Interférométrie de Speckle; Fissures intralaminaires; Endommagement; Interf?rom?trie par granularit?; Composites; Matériaux Fissuration; [SPI.OTHER]Engineering Sciences [physics]/Other; Luleå
• Online Access: https://hal.univ-lorraine.fr/tel-01748768; https://hal.univ-lorraine.fr/tel-01748768/document; https://hal.univ-lorraine.fr/tel-01748768/file/2009_FARGE_L.pdf

This work results from a collaboration between Pr Ayadi (Institut Polytechnique de Lorraine) and Pr Varna (Technical University of Luleå). Since 2005, Pr Varna has developed an original method that allows for the determination of all the thermoelastic constants of a damaged laminate. The stiffness reduction is governed by two parameters: the average value of the opening and the average value of the sliding of the crack surfaces. These values are normalized with respect to the applied loading. In this work, the potential of speckle interferometry is analysed to obtain these two parameters. More generally, we show the usefulness of displacement field measurements to characterize damage development in laminates. The first chapter is dedicated to the damage that occurs in laminates. The main objective is to highlight the points for which displacement field measurements could bring interesting information. In the second chapter, the principle of speckle interferometry is described. The choice of this technique for the considered application is discussed and justified. In the third chapter, an experimental study of the potential of speckle interferometry is proposed to characterize the damage forms that occur in a glass/epoxy laminate. In the last chapter, the development of damage is experimentally analysed in a carbon/epoxy laminate Cette thèse résulte d'une collaboration entre le Pr Ayadi de l'Institut National Polytechnique de Lorraine et le Pr Varna de l'Université Technologique de Luleå. Depuis 2005, le Professeur Varna a développé une méthode originale qui permet d'obtenir l'ensemble des constantes thermoélastiques d'un stratifié endommagé à partir de deux paramètres : l'ouverture moyenne et le glissement moyen des lèvres des fissures, normalisés par rapport à la contrainte appliquée. Dans cette thèse, nous analysons le potentiel de l'interférométrie de speckle pour obtenir la mesure de ces deux grandeurs. Plus généralement, nous montrons l'utilité de la mesure du champ de déplacement pour caractériser le ...