Multi-site delamination detection and quantification in composites through guided wave based global-local sensing

Abstract

Abstract. This paper presents a guided wave based global-local sensing method for rapid detection and quantification of multi-site delamination damage in large composite panels. The global-local approach uses a hybrid system consisting of a piezoelectric transducer (PZT) for generating guided waves and a non-contact scanning laser Doppler vibrometer (SLDV) for acquiring guided wave data. The global-local method is performed in two steps. First, a phased array configured of a small number of SLDV scan points (for example 10×10 points in a rectangular grid array) performs inspection over the entire plate to detect and locate damage. Local areas are identified as potential damage regions for the second step. Then high density wavefield measurements are taken over the identified areas and wavefield analysis is performed to quantitatively evaluate the damage. For the proof of concept in case with multi-site damage, the global-local approach is demonstrated on a carbon fiber reinforced polymer (CFRP) composite plate with two sites of impact-induced delamination damage. In the first step, the locations of two delamination sites are detected by the phased array method. In the second step, the delamination size and shape are evaluated using wavefield analysis. The detected delamination location, size and shape agree well with those of ultrasonic C-scan and the method led to a 93% reduction in inspection time compared to a full SLDV dense grid scan.

Optimal slope angles of the air-coupled transducer from viewpoint of the effective Lamb waves propagation in different materials

“…Authors of [13] conducted four delamination-type defects detection, simulated by thin Teflon film inserts embedded between selected layers of the specimen. Another detection process of such defects was done in [14] and [15] (scientists in [15] considered multi-layered delamination). However, all of these works [13], [14], [15] are related to elastic waves generation by piezoelectric transducer (PZT) instead of ACT.…”

“…Another detection process of such defects was done in [14] and [15] (scientists in [15] considered multi-layered delamination). However, all of these works [13], [14], [15] are related to elastic waves generation by piezoelectric transducer (PZT) instead of ACT. In turn, in [16] delamination defects detection using ACT to generate acoustic waves and scanning laser Doppler vibrometer (SLDV) to detect elastic waves was performed.…”

“…In addition to the desire of defects detection, ACT-based technique can be also used to determine the ultrasounds velocity and their attenuation in the material [22] or to define material properties of the investigated specimen [4], [23]. In case of the ACT usage, some of the works are focused on the experimental research [12], [24], [25] and some of them are focused on both numerical and experimental approach [14], [16], [26]. Authors of [25] put the effort on the research aimed at the weakness of air-coupled signal.…”

Tensile and fatigue testing of impacted smart CFRP composites with embedded PZT transducers for nonlinear ultrasonic monitoring of damage evolution

“…impact events with nearly invisible marks on their surface, known as barely visible impact damage (BVID) [4]. Normally, BVID from bird strikes, hailstorms and tool drops is characterised by delamination, matrix micro-cracking and fibre failure [5]. These material flaws tend to evolve with high rates under operating dynamic stresses and, thus, safety regulations in aviation require frequent inspections of composite structures [6].…”

Optimization of elastodynamic finite integration technique on Intel Xeon Phi Knights Landing processors

“…Guided wave damage detection and quantification techniques reported in the literature range from sparse data methods via sensor arrays to dense data methods utilizing full wavefield imaging through laser Doppler vibrometry. Numerous authors have reported on experimental guided wave techniques and simulation-aided investigation of guided wave methods [12] [13] [14] [15] [16] [17] [18]. For both bulk and guided wave based ultrasound methods, realistic ultrasound simulation tools can significantly aid the development and optimization of inspection techniques and can assist in the interpretation of experimental data.…”