crack ciel gestion commerciale evolution 6.1

Even if there exist numerous publications on this so-called direct and reciprocal piezoelectric effect, the aim of this paper is to convey a clear and easy understanding of this essential solid body effect in particular for the non-specialist, since a large number of publications is rather superficial and unfortunately sometimes incorrect.

Contrary, a mechanical deformation results in a generation of polarization charges. quartz, turmaline) are subjected to electrical signals along certain crystal orientations, deformations along well-defined crystal orientations appear. The piezoelectric effect, which was discovered for the first time by the brothers Pierre and Jacques Curie, combines electrical with mechanical quantities and vice versa. These two quantification methods, one based on data and the other on a physical model, have been validated on signals from numerical simulations and on experimental signals from structures with realistic damages. Based on this theoretical model, an identification tool is proposed to estimate the damage size and severity. This model is limited to quasi-isotropic composite material and has been validated by comparison to finite elements method simulations. To solve this inverse problem, an analytical model is developed to predict the signal measured by a piezoelectric sensor at the passage of a wave generated by a piezoelectric actuator and scattered by a damage. The third contribution is the development and validation of a quantification method that relies on the estimation of damage-related parameters from a physical model and does not require reference data. The second contribution is the development and validation on damage of unknown size of a purely data-driven quantification approach that consists in training a mathematical model from labeled data and an original mathematical descriptor computed from localization images. The first contribution of this thesis is the creation and publication of an open access and reusable database of SHM measurements from fatigue tests of composite structures representative of aeronautics components. The general objective is to propose and validate experimentally several methods to quantify the size of a delamination type damage present in the structure to be monitored. This thesis concerns the structural health monitoring of aeronautical composite structures (SHM) using guided waves generated by piezoelectric transducers.

Crack ciel gestion commerciale evolution 6.1