Journal ArticleDOI
Contacting surfaces: A problem in fatigue and diffusion bonding
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In this paper, the authors deal with the non-destructive evaluation of the topology of contact and with the use of this information to predict the effects that loads borne by these contacts have on mechanical properties.Abstract:
Contact between surfaces usually occurs at asperities under compression or at connecting ligaments, depending on how the interface is formed. This paper deals with the nondestructive evaluation of the topology of contact and with the use of this information to predict the effects that loads borne by these contacts have on mechanical properties. Two specific examples are discussed: a fatigue crack and a diffusion bond. Asperity contact along the fracture surface of a fatigue crack partially shields the crack tip from the externally applied driving force. Using information from acoustic experiments, the geometry of the asperities, the contacting stress, and the shielding stress intensity factor have been estimated. Acoustically, a diffusion bonded interface looks very similar to that joining the two sides of a partially closed crack. In this particular case, the acoustically determined geometry of well-bonded ligaments can be verified by fractography of destructively tested samples whose bond strength has also been determined. Models to determine the bond strength from the ligament geometry are being suggested.read more
Citations
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Journal ArticleDOI
Nondestructive characterization of the mechanical strength of diffusion bonds. II. Application of a quasi-static spring model
TL;DR: In this article, experimental data on the geometry of the contacts between two diffusion-bonded blocks have been used to determine the "spring stiffness" of such interfaces which have been correlated with experimentally determined ultrasonic reflection coefficients.
Journal ArticleDOI
Nondestructive characterization of the mechanical strength of diffusion bonds. I. Experimental results
TL;DR: The application of ultrasonic reflectivity for the characterization of a variety of copper diffusion bonds is described in this paper, where the quality of each diffusion bond has been described by its ultimate tensile strength.
Journal ArticleDOI
Effective spring stiffness for a periodic array of interacting coplanar penny-shaped cracks at an interface between two dissimilar isotropic materials
TL;DR: An effective spring stiffness approximation is proposed for a hexagonal array of coplanar penny shaped cracks located at the interface between two dissimilar solids, useful for an assessment by ultrasonic measurements of the interface stiffness in bonded structures for monitoring the interfacial microdamage growth due to mechanical loading and environmental factors.
Proceedings ArticleDOI
Ultrasonic nondestructive evaluation of solid-solid bonds
TL;DR: In this paper, a discussion of theories for the interaction of ultrasound with such distributed defects, results of model experiments designed to validate the theories, and applications of techniques based on the resulting understanding to fracture studies of bonded surfaces and to inspection of aircraft engine turbine rotors.
Journal ArticleDOI
Reflection Phase Measurements for Ultrasonic NDE of Titanium Diffusion Bonds
Edwill Escobar-Ruiz,Edwill Escobar-Ruiz,David Cameron Wright,Ian J. Collison,Peter Cawley,Peter B. Nagy,Peter B. Nagy +6 more
TL;DR: In this article, significant improvements to the existing phase measurement approach are proposed alongside adaptations that permit its broader practical implementation, and principal parameters that affect the phase analysis of ultrasonic signals were investigated and their optimisation resulted in up to an order of magnitude improvement in phase measurement reliability, even at low signal-to-noise ratios.
References
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Book
The stress analysis of cracks handbook
TL;DR: The Stress Analysis of Cracks Handbook as mentioned in this paper provides a comprehensive, easy-to-access collection of elastic stress solutions for crack configurations, along with other relevant information, such as displacements, crack opening areas, basic stress functions source references, accuracy of solutions, and more.
BookDOI
Review of Progress in Quantitative Nondestructive Evaluation
TL;DR: The Review of Progress in Quantitative NDE (ROPQN) as mentioned in this paper is the world's leading conference in reporting annually new research and development results in quantitative NDE and promotes communication between the research and engineering communities and emphasize current reporting of work in progress.
Book ChapterDOI
The Significance of Fatigue Crack Closure
TL;DR: Al alloy sheet fatigue crack closure under cyclic tensile loading, deriving expression for crack propagation rate in terms of effective stress amplitude as discussed by the authors, was derived for the first time in the literature.
Journal ArticleDOI
Ultrasonic scattering from imperfect interfaces: A quasi-static model
Jai-Man Baik,R. Bruce Thompson +1 more
TL;DR: In this article, a quasi-static model for ultrasonic transmission and reflection at imperfect interfaces is developed, where the interface is represented by a distributed spring determined by the change in static compliance of the medium with respect to one with a perfect interface, and a distributed mass, representing excess mass at the interface.
Journal ArticleDOI
General electromechanical reciprocity relations applied to the calculation of elastic wave scattering coefficients
TL;DR: In this article, general electromechanical reciprocity relations are applied to the calculation of elastic wave scattering coefficients observed at the electrical terminals of the transducer used in performing an experiment.
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