Kim, Jin-Hwan (2008) Identification of the local stiffness reduction of damaged composite plates using the virtual fields method. PhD thesis Mécanique, Mécanique et procédés de fabrication CER de Châlon-en-Champagne, ENSAM 2008ENAM0026 p.169.
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Abstract
The present study aims at taking advantage of the availability of full-field measurements and adapted inverse identification procedures in order to not only locate the damage but also to identify the local stiffness reduction of a damaged composite plate. To do so, full-field heterogeneous curvature fields are obtained through a deflectometry technique. The virtual fields method (VFM) is used as an inverse procedure to process curvatures for the identication of the local loss of stiffness. The VFM is based on a relevant use of the equilibrium equations through the principle of virtual work. It has been adapted to the case of a plate with stiffnesses varying with the space variables. Two parameterization methods for the stiffness reduction were developed: discrete (piecewise) and continuous (polynomial). In this study, the procedure is described, validated on simulated measurements and several experimental results are given. The method not only picks up the location of the damage but also provides a fairly good estimate of the stiffness reduction in the damaged area when through-the-thickness displacement distribution in the damaged region is linear. However, the current methodology shows unsatisfactory identification if the distribution is not linear, which is the case for a single mid-plane delamination.
| Item Type: | PhD Thesis (PhD) |
|---|---|
| PhD Supervisor: | Pierron, Fabrice |
| Date: | 12 November 2008 |
| Board of examiners: | Grédiac, Michel and Vautrin, Alain and Guillaumat, Laurent and Avril, Stéphane and Wisnom, Michael and Pierron, Fabrice |
| Ecole Doctorale: | ED 432 ECOLE DOCTORALE SCIENCES DES METIERS DE L'INGENIEUR |
| Discipline: | Mécanique |
| Collection (Fonds): | Arts et Métiers ParisTech (ENSAM) |
| Institution: | ENSAM |
| Department: | Mécanique et procédés de fabrication CER de Châlon-en-Champagne |
| Subjects: | 4. Materials Science, Mechanics and Mechanical Engineering |
| Uncontrolled Keywords: | Détection de l'endommagement, Mesures de champs, Défectométrie, Réduction locale de rigidité, Virtual fields method, Damage detection |
| ID Code: | 4959 |
| Deposited By: | Jin-Hwan Kim |
| Deposited On: | 23 June 2009 |
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