Design of distributed sparse arrays for Lamb wave SHM based upon estimated scattering matrices

Abstract

Model-based imaging of damage with Lamb waves via sparse reconstruction J. Acoust. Soc. Am. 133, 1525 (2013); 10.1121/1.4788984 Estimation of guided wave scattering matrices from spatially distributed transducer arrays AIP Conf. Abstract.A common practice in guided wave structural health monitoring is collecting measurements from a transducer array using the pitch-catch method. Among different array configurations, the spatially distributed array provides a costeffective solution for rapid interrogation of large, plate-like structures. Several guided wave imaging techniques have been proposed and successfully demonstrated for damage detection and localization. However, the performance of these imaging methods can be compromised by a mismatch between a particular transducer array geometry and the scattering characteristics of a defect of interest. This study proposes a method, which is based upon estimating scattering matrices, to quantify the ability of a specific array geometry to interrogate a scatterer. Several array geometries are evaluated using this method, and a Monte Carlo simulation is then performed to vary the transducer locations to find the array geometry that is best matched to a specific directional scatterer. The efficacy of the proposed method is evaluated experimentally by introducing notches of different orientations and locations on an aluminum plate specimen that is instrumented with a spatially distributed array.

A simplified framework for prediction of sensor network coverage in real-time structural health monitoring of plate-like structures

“…Detailed discussion of the directionality effect of Lamb wave reflection from crack has been provided in the literature. 52,53 A reciprocal function is proposed in equation ( 2) to estimate the back-scattered field in the radial direction (r direction shown in Figure 5)…”

“…Detailed discussion of the directionality effect of Lamb wave reflection from crack has been provided in the literature. 52,53

Figure 5.Parameters of the function used for back-scattered field estimation.

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Guided wave phased array beamforming and imaging in composite plates

“…9into Eq. 13, we can derive, (16) Or using array span and spacing as, (17) Eq. 17 Figure 4a, where on maxima is on the dispersion curve of A 0 mode.…”

“…When generating inspection results, an image of the structure being inspected often gives an efficient solution that quickly identifies and locates defects. Various imaging methods based on GW NDE have been explored including tomography [6,[14][15][16], sparse array [7,[17][18][19][20][21][22][23][24], synthetic aperture focusing technique [25][26][27], reconstruction algorithm for probabilistic inspection of damage (RAPID) [5,[28][29][30], and phased array [8,. Among them, the phased array imaging is attractive since it uses sensors that are placed closed to each other in a compact format, steers the outputs of all sensors in a desired direction, and inspects the entire structure like a radar [31].…”

Influence of the PZT Sensor Array Configuration on Lamb Wave Tomography Imaging with the RAPID Algorithm for Hole and Crack Detection

“…Hall and Michaels [14] explored the sensor number and the pattern of a PZT sensor array on the image performance by a conventional delay-and-sum imaging algorithm. Chen [15] proposed a scattering matrix estimation method to quantify the ability of a PZT sensor array to interrogate a specific directional scatter. Zhao [6] compared the theoretical resolutions in a reconstruction image with that of circular, square, and parallel linear PZT sensor arrays.…”