Comparison of Ultrasonic Non-Contact Air-Coupled Techniques for Characterization of Impact-Type Defects in Pultruded GFRP Composites

Abstract

This article compares different air-coupled ultrasonic testing methods to characterize impact-type defects in a pultruded quasi-isotropic glass fiber-reinforced plastic (GFRP) composite plate. Using the air-coupled transducers, comparisons among three methods were performed, namely, bulk-wave through transmission, single-side access using guided waves, and ultrasonic-guided wave tomography. The air coupled through transmission technique can determine the size and shape of impact-type defects with a higher resolution, but with the consequence of time consumption and, more importantly, the necessity of access to both sides of the sample. The guided wave technique on the other hand, allows a single-side inspection and is relatively fast. It can be used to determine the size of the defect using ultrasonic B-scan, but the exact shape of the defect will be compromised. Thus, in this article, to determine the shape of the defect, application of the parallel beam tomographic reconstruction technique using guided Lamb waves is demonstrated. Furthermore, a numerical finite element simulation was performed to study the effects of guided wave propagation in the composite sample and interaction with the internal defect. Lastly, the results from the experiments of different techniques were compared according to possibilities of defect sizing and determination of its shape.

Non-Destructive Detection of Real Defects in Polymer Composites by Ultrasonic Testing and Recurrence Analysis

“…Non-destructive tests are also used to test the elastic properties of composite materials [ 34 , 35 ]. The through-transmission method as well as the Phased Array (PA) method make it possible to detect defects inside composite materials [ 36 ]. Previous studies have demonstrated that defect orientation can have a significant impact on its detection.…”

Defect Detection Method of Carbon Fiber Sucker Rod Based on Multi-Sensor Information Fusion and DBN Model

“…Cerniglia [ 9 ] proposed a laser ultrasonic technique for the in-line inspection of laser powder deposition components. Asokkumar [ 10 ] compared different air-coupled ultrasonic testing methods to characterize impact-type defects in a pultruded quasi-isotropic GFRP composite plate. However, this method is not suitable for the carbon fiber rod with the irregular interlayer interface.…”

Imaging of Increasing Damage in Steel Plates Using Lamb Waves and Ultrasound Computed Tomography

“…The second approach is connected with the use of an array of piezoelectric transducers, acting as both actuators and sensors, attached to selected points on an analysed structure. Wave propagation signals are collected and then processed using appropriate damage detection algorithms such as the time of flight (TOF) based triangulation method [ 3 ], supported by ellipse or hyperbolic probability imaging [ 4 , 5 ], the time-reversal technique [ 6 ], the migration technique [ 7 ], phased-array beamforming [ 8 ] and finally ultrasound tomography, widely used for inspection of structures made of concrete [ 9 , 10 , 11 ], metal [ 12 , 13 , 14 ] and composite materials [ 15 , 16 ].…”