Network wavefield imaging methods for quantification of complex discontinuity in plate-like structures

Abstract

Network wavefield imaging methods are able to image significantly complex discontinuities or shapes in plate-like structures for superior ultrasonic structural health monitoring (SHM)/nondestructive evaluation (NDE). The imaging provides high-resolution location, shape and/or size images of a structure, and for discontinuities with more complicated profiles. Guided wave (GW) network wavefield imaging methods combine tomography and wavefield/wavenumber imaging algorithms. Metallic plate damage detection uses guided ultrasonic waves and non-contact laser vibrometry. Guided waves are generated by piezoelectric transducers (PZT). A non-contact scanning laser Doppler vibrometer (SLDV) measures the full velocity plate guided wave wavefields. Developed network wavefield imaging algorithms account for multiple-actuator excitations from different angles enclosing the discontinuity, with algorithms using intrinsic wave characteristics such as wavefield, wavenumber, or reconstructed wave energy. Determined locations, sizes and shapes of highlighted areas in wavefield, wavenumber and/or filter reconstructed energy-based images correlate with location, size and shape of damage in metallic plates.