Interfacial spring model for ultrasonic interactions with imperfect interfaces: Theory of oblique incidence and application to diffusion-bonded butt joints

Margetan, F. J.; Thompson, R. B.; Gray, T. A.

doi:10.1007/bf00565998

Cited by 92 publications

(76 citation statements)

References 17 publications

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“…Notice that the sound path has three legs within the metal, and that each leg can be traversed with either longitudinal (L) or transverse (T) sound waves. For single-probe inspections of such bonds, theoretical studies [2] using the DS model suggest two optimal inspection geometries. In the notation of Ref.…”

Section: Experiments On Diffusion-bonded Specimensmentioning

confidence: 99%

“…In the notation of Ref. [2] these are: LLL (L-wave along each leg) with the sound waves striking the bond at near-grazing incidence; and TTT ( T-wave along each leg) with sound striking the bond at near-450 incidence. Model studies in Ref.…”

Section: Experiments On Diffusion-bonded Specimensmentioning

confidence: 99%

“…Model studies in Ref. [2] suggest that the TTT inspection would best for INlOO alloys, and that LLL would be preferred for course-grain titanium alloys.…”

Section: Experiments On Diffusion-bonded Specimensmentioning

confidence: 99%

“…Since many defect distributions can give rise to the same mass and stiffness constants, low-frequency specular reflection measurements can provide only incomplete knowledge of the distribution, even when the defect type is known. For example, if the bond plane contains a sparse distribution of identical flat circular cracks, such reflectivity measurements can determine only the product of the crack area fraction and the crack diameter [2,3]. Recent theoretical work employing an independent scattering (IS) model [4,5] predicts that resonance peaks in reflectivity-vsfrequency (R-vs-f) curves, which occur when A. and the average defect diameter are similar, can be used to size the defects.…”

Section: Introducitonmentioning

confidence: 99%

“…of the interrogating sound is large compared to the characteristic defect size, the quasi-static distributed-spring (DS) model applies [1]. This model can serve as a useful tool for interpreting signals reflected from imperfect bonds, and for choosing inspection parameters to optimize the inspection of a given bonded structure [2]. The DS model predicts that the low-frequency specular reflection properties of an imperfect bond are solely determined by a small number of inertia and stiffness constants which characterize the defect layer.…”

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confidence: 99%

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Experimental Studies Pertaining to the Interaction of Ultrasound with Metal-Metal Bonds

Margetan

Thompson

Gray

et al. 1990

Review of Progress in Quantitative Nondestructive Evaluation

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INTRODUCITONThe problem of deducing the integrity of a diffusion bond using reflected ultrasound is a difficult one, since many defect structures can be imagined which reflect sound in essentially similar fashions but have different failure consequences When an imperfect bond consists of a near-planar distribution of small defects, and the wavelength (A.) of the interrogating sound is large compared to the characteristic defect size, the quasi-static distributed-spring (DS) model applies [1]. This model can serve as a useful tool for interpreting signals reflected from imperfect bonds, and for choosing inspection parameters to optimize the inspection of a given bonded structure [2]. The DS model predicts that the low-frequency specular reflection properties of an imperfect bond are solely determined by a small number of inertia and stiffness constants which characterize the defect layer. Since many defect distributions can give rise to the same mass and stiffness constants, low-frequency specular reflection measurements can provide only incomplete knowledge of the distribution, even when the defect type is known. For example, if the bond plane contains a sparse distribution of identical flat circular cracks, such reflectivity measurements can determine only the product of the crack area fraction and the crack diameter [2,3]. Recent theoretical work employing an independent scattering (IS) model [4,5] predicts that resonance peaks in reflectivity-vsfrequency (R-vs-f) curves, which occur when A. and the average defect diameter are similar, can be used to size the defects. Resonance information could then be used to complement the low-frequency specular reflection data, thus permitting the determination of both average defect diameter and total defect area fraction. In the present work we report on several experiments carried out to examine the feasibility of this procedure. Specifically, we report on measurements of R-vs-f for longitudinal sound waves at normal incidence carried out in three model systems containing near-planar distributions of defects: cylindrical inclusions in water; cylindrical voids in iron; and spherical inclusions in plastic. The measurements are compared with the predictions of the DS and IS models. It is found that the IS model accurately predicts the frequency of the first peak in the R-vs-f curve, which is directly releated to the size of the defects.In the second section, we consider optimized oblique-incidence reflection measurements in two classes of diffusion-bonded metal specimens supplied to us by aircraft engine manufacturers. Experiments on four bonded Ti-6Al-4V specimens were carried out to ascertain the ability of low-frequency reflection measurements to distinguish contaminated and uncontaminated regions of diffusion bonds. Experiments on four IN100 specimens were performed to similarly gauge the ability of such measurements to distinguish bonds created using different temperature-pressure-upset recipes. In the final section we conclude with a brief summary of our fmdings.

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Section: Experiments On Diffusion-bonded Specimensmentioning

confidence: 99%

Section: Experiments On Diffusion-bonded Specimensmentioning

confidence: 99%

“…Model studies in Ref. [2] suggest that the TTT inspection would best for INlOO alloys, and that LLL would be preferred for course-grain titanium alloys.…”

Section: Experiments On Diffusion-bonded Specimensmentioning

confidence: 99%

Section: Introducitonmentioning

confidence: 99%

mentioning

confidence: 99%

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Experimental Studies Pertaining to the Interaction of Ultrasound with Metal-Metal Bonds

Margetan

Thompson

Gray

et al. 1990

Review of Progress in Quantitative Nondestructive Evaluation

Self Cite

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Enhanced characterization of fracture compliance heterogeneity using multiple reflections and data‐driven Green's function retrieval

Minato

Ghose

2016

JGR Solid Earth

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The spatial heterogeneity along a fracture is a key determinant for fracture‐associated mechanical and hydraulic properties of the subsurface. Laboratory experiments have been performed to test the applicability of the nonwelded interface representation to predict the frequency‐ and angle‐dependent elastic response of a single fracture. The observation that nonwelded interface model can represent quite well the frequency‐ and angle‐dependent reflection response of a fracture has led us to develop a new methodology for estimating the spatially heterogeneous fracture compliance from the reflection response along a fracture surface. A data‐driven approach based on Marchenko equation coupled with inverse scattering to solve the nonwelded interface boundary condition has been formulated. The approach estimates the elastic wavefield along a fracture accurately, including the multiple reflections. As an extension, it offers the possibility to estimate fracture compliance using the multiple reflections. We illustrate the concept by numerically modeling 2‐D SH waves sensing the heterogeneous tangential compliance of a fracture. The stationary phase method is applied to single and double spatial integrals to analyze the effect of source and receiver aperture on the Green's function retrieval. Our results show that the use of multiple reflections allows a better estimation of the heterogeneous fracture compliance than using primary reflections alone, especially for the far offsets on the fracture plane.

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Stress wave propagation and incompatible deformation mechanisms in rock discontinuity interfaces in deep‐buried tunnels

Zhang

Zhu

Wang

et al. 2022

Deep Underground Science and Engineering

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Complex weak structural planes and fault zones induce significant heterogeneity, discontinuity, and nonlinear characteristics of a rock mass. When an earthquake occurs, these characteristics lead to extremely complex seismic wave propagation and vibrational behaviors and thus pose a huge threat to the safety and stability of deep buried tunnels. To investigate the wave propagation in a rock mass with different structural planes and fault zones, this study first introduced the theory of elastic wave propagation and elastodynamic principles and used the Zoeppritz equation to describe wave field decomposition and develop a seismic wave response model accordingly. Then, a physical wave propagation model was constructed to investigate seismic waves passing through a fault, and dynamic damage was analyzed by using shaking table tests. Finally, stress wave attenuation and dynamic incompatible deformation mechanisms in a rock mass with fault zones were explored. The results indicate that under the action of weak structural planes, stress waves appear as a complex wave field decomposition phenomenon. When a stress wave spreads to a weak structural plane, its scattering may transform into a tensile wave, generating tensile stress and destabilizing the rock mass; wave dynamic energy is absorbed by a low-strength rock through wave scattering, which significantly weakens the seismic load. Wave propagation accelerates the initiation and expansion of internal defects in the rock mass and leads to a dynamic incompatible deformation. This is one of the main causes for large deformation and even instability within rock masses. These findings provide an important reference and guide with respect to stability analysis of rock mass with weak structural planes and fault zones.

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Interfacial spring model for ultrasonic interactions with imperfect interfaces: Theory of oblique incidence and application to diffusion-bonded butt joints

Cited by 92 publications

References 17 publications

Experimental Studies Pertaining to the Interaction of Ultrasound with Metal-Metal Bonds

Experimental Studies Pertaining to the Interaction of Ultrasound with Metal-Metal Bonds

Enhanced characterization of fracture compliance heterogeneity using multiple reflections and data‐driven Green's function retrieval

Stress wave propagation and incompatible deformation mechanisms in rock discontinuity interfaces in deep‐buried tunnels

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