Electromagnetic pulse-induced acoustic testing and the pulsed guided wave propagation in composite/metal adhesive bonding specimens

Abstract

Materials composed of metals and plastic composites joined through adhesive bonding are being increasingly used. However, debonding of such materials may occur during manufacture or use. Nondestructive testing of adhesive bonding structures is required to evaluate their debonding. Herein, electromagnetic pulse-induced acoustic testing (EPAT) was used to detect debonding at the adhesive joint in plastic composite/metal specimens. EPAT uses a pulsed excitation current to generate guided waves in a specimen to detect debonding without contact, which makes it suitable for testing from the plastic composite side. Simulations were performed to analyze acrylic/aluminum (Al) and carbon fiber-reinforced plastic (CFRP)/Al specimens. The results showed that the Lorentz force in the z direction was the dominant mechanism in the generation of guided waves, and mainly the A0-mode Lamb wave was excited. The simulation and experimental results revealed that for specimens where the mechanical parameters of the plastic composite layer differed greatly from those of the metal, such as the acrylic/Al specimen, debonding

Robust Heterojunctions of Metallic Alloy and Carbon Fiber-Reinforced Composite Induced by Laser Processing

“…In practical applications of CFRTP/GFRTP, it is inevitable to confront the issue of achieving high-strength heterojunctions between metals and thermoplastic composites. In view of such demand, various strategies for joining metals and thermoplastics have been developed in past decades such as adhesive bonding [ 5 , 6 ], mechanical fastening [ 7 , 8 ], and thermal welding [ 9 , 10 , 11 ]. In comparison with adhesive bonding or mechanical fastening methods, thermal welding technologies such as laser-assisted joining (LAJ) relied on a thermal conduction process and produced joints showing better environmental adaptability and more homogeneous stress distribution [ 12 , 13 ].…”

Structural health monitoring of adhesive joints using Lamb waves: A review

“…Electromagnetic acoustic transducers (EMAT) were used with adhesive joints by He et al 48 to assess the applicability of LW and shear horizontal waves in the evaluation of thin plate structures. Sun et al 49 used electromagnetic pulse-induced acoustic testing to detect debonding in plastic composite/metal specimens. Comb and interdigital transducers are normally composed by three layers of material, forming a sandwich of two electrodes with a layer of piezoelectric material in the middle, as illustrated in Figure 5.…”

“…Electromagnetic acoustic transducers (EMAT) were used with adhesive joints by He et al 48 to assess the applicability of LW and shear horizontal waves in the evaluation of thin plate structures. Sun et al 49 used electromagnetic pulse‐induced acoustic testing to detect debonding in plastic composite/metal specimens.…”

On Detecting Internal Coating Defects in Pipes using EMAT

“…Recently, Hydrogen has gained interest as an alternate fuel option. The application discussed here involves NDT of high-pressure hydrogen tanks, which are manufactured with carbon-fibre reinforced plastic (CFRP) lined with metal, also called multi-materials where the plastic is bonded with metal [7][8]. The objective is to detect the debonding locations between the lining and CFRP wrapping.…”

“…In these applications, it is not possible to inspect the sample from metallic side and requires performing tests from non-metallic side. Therefore, an electromagnetic pulseinduced acoustic transducer (EPAT) was introduced to generate fundamental asymmetric Lamb modes (A0) to detect the disbonding [7]. The principle of guided wave generation is same for both EPAT and EMAT, where in the former, transmitter probe is an excitation coil and GW is received using velocity or displacement sensors placed at several locations over the sample.…”