https://hal.archives-ouvertes.fr/hal-01059299/document

Development of a laser shock adhesion test for the assessment of weak adhesive bonded CFRP structures

Monitoring the bondline integrity of adhesively bonded joints is one of the most critical concerns in the design of aircraft structures to date. Due to the lack of confidence on the integrity of th...

Integrity monitoring of adhesively bonded joints via an electromechanical impedance-based approach:

Simultaneous detection of in‐plane and out‐of‐plane ultrasonic displacements by a two‐channel confocal Fabry–Perot optical receiver is described. Accuracy is tested by measuring the in‐plane and out‐of‐plane displacements produced by Rayleigh surface waves generated by a piezoelectric transducer and a laser.

Detection of in‐plane and out‐of‐plane ultrasonic displacements by a two‐channel confocal Fabry–Perot interferometer

A system for inspecting adhesive in a composite structure, such as for soft or improperly cured regions, includes a transducer and a processing element. The transducer can transmit a signal, such as an ultrasonic signal, into the adhesive such that at least a portion of the ultrasonic signal can propagate through the adhesive, reflect off of an interface between the adhesive and another material, and propagate back through the adhesive. Upon exiting the adhesive, then, the transducer can receive a reflected portion of the ultrasonic signal. Thereafter, the processing element can identify a defect, such as soft or improperly cured regions, in the adhesive upon a relationship of an amplitude of the reflected portion of the reflected ultrasonic signal to a predefined threshold.

System and method for the inspection of adhesive

Angle‐dependent spectral distortion (ASD) refers to the change in complex spectrum of the signal from the receiving transducer due to change in angular orientation of the reflecting target, i.e., from normal incidence to some non‐normal incidence. The ASD for a fluid–fluid infinite planar interface (IP–ASD) is numerically determined for the cases of a planar piston, spherically focused piston, and nondiffracting (J0 ‐Bessel) transducer geometries. The numerical algorithm employed is based on an equivalent image transducer. Reception of the acoustic pulse is performed using discrete surface integration, based on 3‐D surface mesh generation strategies. Numerical simulations, together with experimental results, are presented for the above transducers for various geometries, reflector distances, and misalignment angles. The results indicate that the IP–ASD significantly alters the spectrum of the received acoustic pulse, and thus must be taken into consideration for quantitative ultrasonic measurements. Final...

Angle-Dependent Spectral Distortion for an Infinite Planar Fluid Fluid Interface

: This state-of-the-art report describes the bonding process, the destructive methods used to measure bond strength, and the various NDE methods that have been evaluated for determining the quality of a bond. These NDE methods include sonics, ultrasonics, acoustic emission, nuclear magnetic resonance, x-ray and neutron radiography, optical holography, and thermography. Each of these methods has shown some limited success in detecting debond conditions. At the present time, however, it appears that only the sonic, ultrasonic, and nuclear magnetic resonance methods have the potential capability to differentiate qualitatively the gradations between a good bond and a debond and thus provide a correlation to bond strength. Nondestructive testing; Adhesive bonds; Adhesive bond testing; Adhesive bond strength; Sonic testing; Ultrasonic testing.

Hegeon Kwun

Papers

Nondestructive Evaluation of Adhesive Bond Quality: State of the Art Review