Damage Characterization Using Guided-Wave Linear Arrays and Image Compounding Techniques

Ricardo Tokio Higuti

doi:10.1109/TUFFC.2010.1646

2010-09-01

PRE

Ricardo Tokio Higuti *

Óscar Martínez-Graullera

Carlos Javier Blanco Martín

A. Octavio

Luis Elvira

F. Montero de Espinosa

DOI：10.1109/TUFFC.2010.1646

原文链接

摘要

En 中文

In this work, a high-resolution imaging method for the inspection of isotropic plate-like structures using linear arrays and Lamb waves is proposed. The evaluation of these components is limited by the low dynamic range resulting from main lobe and side lobe field patterns, and from the narrow-band nature of the Lamb waves. Based on a full matrix array, synthetic aperture technique using all emitter-receiver combinations, different images from the same object are obtained by using different apodization coefficients, which are related to a trade-off between main lobe width and relative side lobe level. Several image compounding strategies have been tested and a new algorithm, based on apodization and polarity diversities between signals, is proposed. However, some effects, such as the dead zone close to the array and reverberations caused by interactions of the wavefront and defects, still limit the quality of the images. The use of spatial diversity, obtained by an additional array, introduces complementary information about the defects and improves the results of the proposed algorithm, producing high-resolution, high-contrast images. Experimental results are shown for a 1-mm-thick isotropic aluminum plate with artificial defects using linear arrays formed by 30 piezoelectric elements, with the low dispersion symmetric mode S0 at the frequency of 330 kHz.

Keyword:

PLATE-LIKE STRUCTURES

WAFER ACTIVE SENSORS

NONDESTRUCTIVE EVALUATION

APODIZATION

INSPECTION

LOCALIZATION

SIGNALS

PHASE