Damage identification for composite structures using a cross-correlation reverse-time migration technique

Jiaze He

doi:10.1177/1475921715602546

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Damage identification for composite structures using a cross-correlation reverse-time migration technique

2015-09-11

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Jiaze He

Fuh‐Gwo Yuan *

DOI：10.1177/1475921715602546

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Abstract

En 中文

This article presents a reverse-time migration technique to image damage by cross-correlating forward and backward propagating wavefields in composite structures using flexural wave signals. First, theory and procedures are presented for damage imaging for composite plates using a zero-lag cross-correlation imaging condition for reverse-time migration, briefly called cross-correlation-based reverse-time migration. The zero-lag cross-correlation was calculated between the forward wavefield and the backward wavefield. The forward wavefield is formed by the excitation from the actuator using a finite difference method, and the backward wavefield is generated by back-propagating the time-reversed scattered wavefield using the same finite difference method. Simulation studies were first examined to verify the capability of using the proposed zero-lag cross-correlation imaging condition to image single and multiple sites of damage. Two experiments were conducted where either the surface-mounted piezoelectric wafers or non-contact laser Doppler vibrometer was used for receiving the scattered wave signals along a linear array. The scattered wave signals were extrapolated in reverse-time to generate backward propagating wavefields. The experimental studies demonstrated that the cross-correlation-based reverse-time migration can accurately locate and image multiple sites of damage with improved resolution and higher efficiency in comparison with classical pre-stack reverse-time migration.

Keywords:

Damage identification

composite structures

reverse-time migration

zero-lag cross-correlation imaging condition

laser Doppler vibrometer

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