Damage localization in composite laminates based on a quantitative expression of anisotropic wavefront

Abstract

In this paper, according to the disperse curve of composite laminates in a low frequency domain, a quantitative relation between anisotropic wavefront and propagation direction is proposed to reveal the direction dependency of Lamb wave propagation in composite laminates. This relation is described by a concise analytic expression, which can effectively incorporate anisotropic wave propagation into damage identification and reasonably determine the time-of-flight (ToF) of the Lamb wave. The reliability and applicability of this quantitative relation are validated by numerical simulations and experiments in three different lay-up composite laminates. Furthermore, combining this quantitative relation and the conventional ToF approach, an effective detection method is developed for damage localization in composite plate-like structures. By using PZT sensors, the method is conducted experimentally in a cross-ply laminate. The Gabor wavelet transform is introduced for signal processing to identify the ToF more exactly. Results indicate that a satisfied damage location can be achieved by considering the orientation dependency of anisotropic wave propagation in composite laminates.

Multi-frequency local wavenumber analysis and ply correlation of delamination damage

“…Sparse piezoelectric sensor arrays have been studied for detection of composite damage in structural health monitoring (SHM) type setups [7,8]. These prior studies have shown that sparse sensor arrays have promise for locating damage regions in composites using a small number of sensors, but may be limited in ability to size and characterize damage.…”

Multiway principal component analysis contributions for structural damage localization

“…According to equations (14) and (15), the damage indicators are basically a sum of terms, each one associated with one variable (sensor-time in the case of unfolded matrix), called contributions. Once a damage has been detected because the indices (Q and T 2 -statistics) take abnormal values, finding the elements of the signal x i which are mainly providing these values (highest contribution), means identifying the sensors, or more specifically, the wave propagation path that was more affected by the damage.…”

“…PCA modeling essentially consists of calculating the projection matrix P for each phase (equation 5), which offers a better and dimensionally reduced representation of the original data X und . Matrix P, renamed P m , will be considered as the model of the undamaged structure, besides the damage statistics by each trial Q und and T 2 und from equations (14) and (15) will be used in the diagnosis as illustrated in Figure 2.…”

“…This matrix X c is projected onto the baseline PCA model (equation 5). Damage statistics by each trial Q c and T 2 c from equations (14) and (15) are calculated to obtain the damage indicator (see Figure 3). To detect whether the current structure has some damage or not, its damage indices must be compared with the obtained from the undamaged structures (see Figure 4).…”

Application of Iterative Maximum Weighted Likelihood Estimation in 3-D Target Localization

“…Time-of-flight (ToF)-the time taken by the ultrasonic pulse to travel from an actuator to a sensor-is a feature extracted from the scattered signals that are widely used in target localization [12,13]. Many studies have reported the successful application of ToF-based methods for target localization [1,4,14,15], but the accuracy is affected by ToF measurement errors.…”