Damage identification in various types of composite plates using guided waves excited by a piezoelectric transducer and measured by a laser vibrometer

Composite materials are widely used in the industry, and the interest of this material is growing rapidly, due to its light weight, strength and various other desired mechanical properties. However, composite materials are prone to production defects and other defects originated during exploitation, which may jeopardize the safety of such a structure. Thus, non-destructive evaluation methods that are material-independent and suitable for a wide range of defects identification are needed. In this paper, a technique for damage characterization in composite plates is proposed. In the presented non-destructive testing method, guided waves are excited by a piezoelectric transducer, attached to tested specimens, and measured by a scanning laser Doppler vibrometer in a dense grid of points. By means of signal processing, irregularities in wavefield images caused by any material defects are extracted and used for damage characterization. The effectiveness of the proposed technique is validated on four different composite panels: Carbon fiber-reinforced polymer, glass fiber-reinforced polymer, composite reinforced by randomly-oriented short glass fibers and aluminum-honeycomb core sandwich composite. Obtained results confirm its versatility and efficacy in damage characterization in various types of composite plates

Deep learning aided topology optimization of phononic crystals

In this work, a novel approach for the topology optimization of phononic crystals based on the replacement of the computationally demanding traditional solvers for the calculation of dispersion diagrams with a surrogate deep learning (DL) model is proposed. We show that our trained DL model is ultrafast in the prediction of the dispersion diagrams, and therefore can be efficiently used in the optimization framework

Detecting multiple small-sized damage in beam-type structures by Teager energy of modal curvature shape

Detection of multiple damage using modal curvature has become a research focus of great significance in recent years. Nevertheless, a noticeable deficiency of modal curvature is its inadequacy in identifying small-sized damage, which usually results in damage signatures being obscured by the global fluctuation trend of modal curvature. To address this deficiency, this study develops a damage feature of Teager energy of modal curvature shape to identify multiple small-sized damage against the global fluctuation trend of the modal curvature. The advantage of this damage feature over the traditional modal curvature in small-sized damage characterization is first verified in analytical cases of cracked beams with various types of boundary condition, and further validated in a cracked carbon-fiber-reinforced polymer composite beam with the mode shapes acquired using a scanning laser vibrometer

Fractal dimension analysis of higher-order mode shapes for damage identification of beam structures

2012-2013 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Detecting multiple small-sized damage in beam-type structures by Teager energy of modal curvature shape

Detection of multiple damage using modal curvature has become a research focus of great significance in recent years. Nevertheless, a noticeable deficiency of modal curvature is its inadequacy in identifying small-sized damage, which usually results in damage signatures being obscured by the global fluctuation trend of modal curvature. To address this deficiency, this study develops a damage feature of Teager energy of modal curvature shape to identify multiple small-sized damage against the global fluctuation trend of the modal curvature. The advantage of this damage feature over the traditional modal curvature in small-sized damage characterization is first verified in analytical cases of cracked beams with various types of boundary condition, and further validated in a cracked carbon-fiber-reinforced polymer composite beam with the mode shapes acquired using a scanning laser vibrometer

Damage detection by using FBGs and strain field pattern recognition techniques

A novel methodology for damage detection and location in structures is proposed. The methodology is based on strain measurements and consists in the development of strain field pattern recognition techniques. The aforementioned are based on PCA (principal component analysis) and damage indices (T 2 and Q). We propose the use of fiber Bragg gratings (FBGs) as strain sensor

Un élément fini de poutre fissurée application à la dynamique des arbres tournants

International audienceDans ce travail on présente une méthode originale de construction d'un élément fini de poutre affectée de fissurations. La souplesse additionnelle due à la présence des fissures est identifiée à partir de calculs éléments finis tridimensionnels tenant compte des conditions de contact unilatéral entre les lèvres. Cette souplesse est répartie sur toute la longueur de l'élément dont on se propose de construire la matrice de rigidité. La démarche permet un gain considérable en temps de calcul par rapport à la représentation nodale de la section fissurée lors de l'intégration temporelle de systèmes différentiels en dynamique des structures

The Minimum Detectable Damage as an Optimization Criterion for Performance-based Sensor Placement

International audienc