Inspection of CFRP aircraft components using guided wavefield imaging in wavenumber-frequency domain

Fiber reinforced polymers, also called composites, have a high specific stiffness/strength and good chemical resistance, making them attractive for use in primary components of aerospace and automotive applications. Though, their heterogeneous and layered structure makes them vulnerable to a range of internal defect types. Detection and assessment of these defects is of utmost importance to assure the structural integrity and performance of the component. Recently, guided wave inspection using Scanning laser Doppler vibrometry (SLDV) has gained a lot of attention due to its contactless, relative fast and flexible inspection approach. This study proposes a damage imaging method based on the analysis of a measured guided wavefield. A piezoelectric actuator, or a pulsed laser, is employed to induce a broadband ultrasonic signal in the part under investigation. The resulting guided wavefield is measured on the sample’s surface using 3D infrared SLDV. An automated filter method in wavenumber-frequency domain is implemented in order to isolate (nonlinear) wave/defect interactions from the measured guided wavefield [1, 2]. Subsequent computation of the band power of the filtered wave components yields a heat map in which anomalies are represented in an exclusive manner. As such, the heat map provides a direct view on the location and size of potential defects. The proposed methodology is demonstrated on several large stiffened CFRP aircraft panels which contain a range of real defects, e.g. matrix defects, low-velocity impact damage, stiffener debond and skin-core debond. The obtained guided wave imaging results are benchmarked and validated using other inspection techniques, e.g. ultrasonic C-scan and flash thermography.

Jaar van publicatie:2023

Toegankelijkheid:Open