Visualization of hidden delamination and debonding in composites through noncontact laser ultrasonic scanning

Damage identification in aircraft composite structures: A case study using various non-destructive testing techniques

“…Staszewski et al [4] applied the Lamb wave technique for detection and localization of BVID in a composite wingbox structure. A similar approach was used by Park et al [7], whose study was focused on detection and localization of debonding and delamination in a composite aircraft wingbox. An advanced NDT technique was developed by the authors of [8], where they describe its application to the damage identification procedure of CFRP aerospace composites.…”

Structural health management utilization for lifetime prognosis and advanced control strategy deployment of wind turbines: An overview and outlook concerning actual methods, tools, and obtained results

“…Ultrasound measurements [49][50][51][52] -Detection of extremely small flaws in material -Imaging of the size, shape, and orientation of flaws -Automated image processing possible -High potential of noncontact optical and sound excitation sources -Detection of internal damages -Mostly used in blade production quality testing -High accuracy concerning damage localization -Requirement on X-ray source and X-ray detector -Long exposure time -Not applicable to continuous in-service monitoring No Visual inspection [63] -Used as supplement to other monitoring techniques -Possibility to detect external damages such as cracks and scratches -Accuracy low -Rarely used standalone -High computational requirements if performed using camera devices Yes No are aimed to be explained in detail. More attention is attracted to offshore WT system as the estimated installment, operation, and maintenance costs are higher in comparison with onshore installments as well as the deployment of SHM for those systems is more challenging due to more complex operating conditions as well as burdensome accessibility to the offshore WT systems.…”

Lamb wave-based BVID imaging for a curved composite sandwich panel

“…In a paper by Park et al [5], the cumulative total wave energy (CTWE) can be calculated to serve as a damage imaging condition to enlighten the area with relative large cumulative energy:…”

“…BVID in particular was detected using guided waves in [3]. In recent years, as a high-frequency laser reception technique, laser Doppler vibrometer (LDV), becomes commercially available, fast fully noncontact laser ultrasonic inspection for isotropic plates [4] and composites [5] based on guided wave has received much attention. The C-17 aileron in this research is made of composite sandwich materials.…”

“…When the wavelength is comparable to the damage size, multiple reflections from different sides of damage boundaries result in standing waves, such that a large amount of energy is "trapped" in the damage region. Based on this phenomenon, Park, An and Sohn [5] developed damage imaging conditions using cumulative SWE (CSWE) and also compared CSWE with the cumulative total wave energy (CTWE). Another approach to use the incident and reflected wavefields for damage imaging is a zero-lag cross-correlation (ZLCC) imaging condition [9,10], which is based on the fact that the incident and scattered wavefields are time-coincident to each other only at the damage boundaries.…”