Debonding detection in a carbon fibre reinforced concrete structure using guided waves

Abstract

Guided waves are conventionally used in different non-destructive testing applications because of their cost-effectiveness and light-weight transducers that are easy to incorporate into the structure. The non-destructive evaluation of interfacial defects such as debonding in the composite structure is critical for the safety and long-term use. This paper presents a guided wave technique to detect a variety of debondings in carbon fibre reinforced concrete structure.Five composite specimens were prepared with different debondings: lengthwise, widthwise and patch debonding at different positions of the specimen with respect to the transducers. The guided wave received by the signal at a perfect bonding is taken as a reference. This signal is compared with the received signal at the different debonding conditions. The quantification of the debonding was performed using three damage indices: correlation coefficient, change in P2P and root mean square deviation. The results confirmed that the damage indices correlate linearly with the extent of the debonding which can be used to predict the debond conditions. This method is effective in the non-destructive detection of interfacial defects in an existing structure without special preparation.

Crack Identification in Necked Double Shear Lugs by Means of the Electro-Mechanical Impedance Method

“…SHM based on guided waves can be used to monitor large thin-walled structures, as guided waves have the ability to travel over long distances with little loss of energy [ 24 ] and strongly interact with structural changes. Hence, guided waves can be used to detect structural damages of many kinds, such as cracks in riveted plates [ 25 ], delaminations in composite materials [ 26 ], debondings in carbon fiber reinforced concrete structures [ 27 ], among many others. However, guided wave-based SHM methods need advanced signal processing to correctly interpret the complex signals back-scattered from structural boundaries and potential damages, which is particularly challenging for complex and small structural components as the necked double shear lug considered in the present investigation.…”

Wave Propagation and Scattering due to Debonding in CFRP Strengthened Reinforced Concrete Beams

“…Despite the fact the acoustic emission, ultrasonic detection, infrared thermography, electrochemical impedance spectroscopy and PZT methods can successfully detect the bond defect between concrete and CFRP, few of them have been implemented successfully to interfacial damage monitoring [20]. Moreover, the guided wave techniques described above require embedded PZTs inside the structure which require special interrogation and preparation [21]. In addition, some of the mentioned techniques involve access to the FRP lamina.…”

An EMI-Based Clustering for Structural Health Monitoring of NSM FRP Strengthening Systems

“…Although some attempt has been made in the past for EB FRP reinforcement using this approach, the limitations are clear [15]. More frequently, different statistical metrics, such as the root mean square deviation (RMSD), the correlation coefficient (CC), or the covariance (Cov), have been used to characterize damage from changes of the impedance signatures [16,17]. However, the use of a single type of metric for EMI based identification has some limitations regarding damage location and severity.…”