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Nouvelle méthode d'évaluation de la santé d'un composite fondée sur l'interaction des modes de flexion et de torsion.

Abstract : Despite high interest in composite materials (mechanical performance and mass reduction), their application in the automotive transport industry is still limited: suspension, wheels, steering connection elements. In order to ensure the reliability of these safety-critical parts (regardless of the application industry), it is essential to dimension them properly in the design phase to validate the prototypes correctly and, especially, to be able to diagnose their health status throughout their lifetime. Nowadays, multiple methods are available, but measuring equipment they use is often expensive, with long acquisition and post-processing times, and often requiring immobilising the vehicle or extracting parts of its structure. It is therefore desirable to develop a non-intrusive measurement method allowing the assessment of material degradation, from a mesoscopic to a structural scale (cracking, delamination, ...), without the need to disassemble the structure. Using the principles of experimental modal analysis, we aim at establishing a clear link between the evolution of certain modal parameters and the damage observed under monotonous tensile tests. The idea consists, in introducing specific degradation, controlled by the orientation of composite plies, and then allowing it in the specimen to appear in a natural way (for instance originating from a porosity) in order to characterise the modal basis for several stages of loading and degradations. In order to do this, the vibratory excitation is applied via a piezoelectric actuator, the response of the system is measured by a 3D vibrometer laser and the damage identification is carried out along a section of the specimenusing a motorised optical microscope. We propose a vibration criterion, using a combination of bending and torsion modes. This experimental vibration health criterion is then compared to its digital counterpart in order to validate its relevance.
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Submitted on : Thursday, March 11, 2021 - 2:57:12 PM
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  • HAL Id : tel-03166756, version 1

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Olivier Ponte Felgueiras. Nouvelle méthode d'évaluation de la santé d'un composite fondée sur l'interaction des modes de flexion et de torsion.. Matériaux. Université Paris sciences et lettres, 2020. Français. ⟨NNT : 2020UPSLM055⟩. ⟨tel-03166756⟩

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