Delamination imaging in composites using cross-correlation method by non-contact air-coupled Lamb waves

Abstract

This paper presents a cross-correlation damage detection technique using damage scattered waves of all directions cross-correlate with the incident waves for delamination imaging in carbon fiber reinforced polymer (CFRP) composite plate. The presented imaging can not only detect the delamination but also precisely quantify the damage with locations and sizes. First, a CFRP composite sample with interlaminar delamination by inserting the Teflon layer is designed and manufactured in house using the hot-press machine. And three-dimensional (3D) model of composite sample is simulated using the finite element method. Next, the cross-correlation imaging algorithm is introduced in detail, and the cross-correlation imaging proof-of-concept study is conducted with the simulated Lamb waves in the composite sample. Finally, a fully non-contact air-coupled transducer and scanning laser Doppler vibrometer system with a single-mode Lamb wave method is established to actuate and sense the interrogating Lamb waves in the structure. The imaging method is experimentally implemented for the one delamination and two delaminations imaging and quantification.

Developing self-calibrating system for fiber Bragg grating based guided wave sensing under changing temperature conditions

“…Apart from PZT, macrofiber composites and magnetorestrictive transducers have been used in the literature as well [2]. In recent times actuation using non contact techniques such as acoustic transducers and pulsed lasers have been proposed [3][4][5][6]. For the sensing, the active devices mentioned above have been paired up with scanning laser Doppler vibrometry as well as optical fiber based sensors such as Fabry-Pérot interferometers or fiber Bragg grating (FBG) sensors.…”

Evaluating impact damage on carbon fiber-reinforced polymer plates utilizing zero-group-velocity Lamb waves

“…Ahn et al [24] explored the assessment of microcrack damage in concrete using air-coupled ultrasonic transducers, while Zhang et al [25] proposed a damage assessment method for millimeter-level damage in braided CFRP structures based on air-coupled ultrasonic transducers. Yu et al [26] achieved delamination imaging and quantification of CFRP plates through air-coupled ultrasonic transducers. To date, there have been limited reports on the evaluation of impact damage in composite plates utilizing air-coupled ultrasonic transducers and ZGV modes.…”