Some studies on evaluation of degradation in composite adhesive joints using ultrasonic techniques

Kumar, Vijaya RL and Bhat, MR and Murthy, CRL (2013) Some studies on evaluation of degradation in composite adhesive joints using ultrasonic techniques. In: Ultrasonics, 53 (6). pp. 1150-1162.

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Abstract

Experimental and theoretical studies on degradation of composite-epoxy adhesive joints were carried out on samples having different interfacial and cohesive properties. Oblique incidence ultrasonic inspection of bonded joints revealed that degradation in the adhesive can be measured by significant variation in reflection amplitude as also by a shift in the minima of reflection spectrum. It was observed that severe degradation of the adhesive leads to failure dominated by interfacial mode. Through this investigation it is demonstrated that a correlation exists between the bond strength and a frequency shift in reflection minimum. The experimental data was validated using analytical models. Though both bulk adhesive degradation and interfacial degradation influences the shift in spectrum minimum, the contribution of the latter was found to be significant. An inversion algorithm was used to determine the interfacial transverse stiffness using the experimental oblique reflection spectrum. The spectrum shift was found to depend on the value of interfacial transverse stiffness using which a qualitative assessment can be made on the integrity of the joint.

Item Type:	Journal Article
Publication:	Ultrasonics
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Keywords:	Adhesive Joints; Ultrasonics; Adhesive Degradation; Interfacial Stiffness
Department/Centre:	Division of Mechanical Sciences > Aerospace Engineering(Formerly Aeronautical Engineering)
Date Deposited:	27 Jun 2013 07:56
Last Modified:	27 Jun 2013 07:56
URI:	http://eprints.iisc.ac.in/id/eprint/46743

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