Study of the Heat Generation Mechanism in Acoustic Thermography

Homma, C.; Rothenfusser, M.; Baumann, J.; Shannon, Robert V.

doi:10.1063/1.2184578

Cited by 42 publications

(33 citation statements)

References 2 publications

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“…Crack growth, however, can cause heat generation in the plastic zone beyond a crack tip due to plastic deformations in the crack's plastic zone. Viscoelastic heating is negligible in most metals, but can be a significant heat source for polymer-based materials [3,11]. Viscoelastic heating is evidenced by bulk heating of the structure from the vibrational stress with additional localized heating at regions of stress concentration, so it is generally possible to distinguish between plasticity-induced and viscoelastic-induced heating.…”

Section: Theorymentioning

confidence: 99%

The sources of heat generation in vibrothermography

Renshaw

Chen

Holland

et al. 2011

NDT & E International

155

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Vibrothermography, or sonic IR, is a nondestructive evaluation technique used to find surface and near surface defects-such as cracks and delaminations-through observations of vibration-induced heat generation. This method has significant interest as an industrial inspection method, however, a lack of understanding of the fundamental physics governing the heat generation process has limited its application despite extensive theoretical, numerical simulation, and experimental work. Significant theoretical and numerical simulation work has been performed, but has yet to be rigorously verified experimentally. This paper presents experimental verification of the sources of heat generation in vibrothermography; specifically friction, plasticity, and viscoelasticity. Specific experimental evidence is presented that verifies each of these heat-generating mechanisms.

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Section: Theorymentioning

confidence: 99%

The sources of heat generation in vibrothermography

Renshaw

Chen

Holland

et al. 2011

NDT & E International

155

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“…Though the physics of viscoelastic heat generation in synthetic defects [2] is different from friction in cracks [9], the trends of the temperature rise versus local vibrational stress graphs are surprisingly similar, leading to the conclusion that VMF defects are both useful and appropriate synthetic defects that can be utilized to improve inspection coverage using vibrothermography.…”

Section: Resultsmentioning

confidence: 99%

Synthetic Defects for Vibrothermography

Renshaw¹,

Holland²,

Thompson³

et al. 2010

AIP Conference Proceedings

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Synthetic defects are an important tool used for characterizing the performance of nondestructive evaluation techniques. Viscous material-filled synthetic defects were developed for use in vibrothermography (also known as sonic IR) as a tool to improve inspection accuracy and reliability. This paper describes how the heat-generation response of these VMF synthetic defects is similar to the response of real defects. It also shows how VMF defects can be applied to improve inspection accuracy for complex industrial parts and presents a study of their application in an aircraft engine stator vane. ABSTRACT. Synthetic defects are an important tool used for characterizing the performance of nondestructive evaluation techniques. Viscous material-filled synthetic defects were developed for use in vibrothermography (also known as sonic IR) as a tool to improve inspection accuracy and reliability. This paper describes how the heat-generation response of these VMF synthetic defects is similar to the response of real defects. It also shows how VMF defects can be applied to improve inspection accuracy for complex industrial parts and presents a study of their application in an aircraft engine stator vane.

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“…Typically, elastic waves in the frequency range from 15 kHz to 70 kHz are introduced to the material in a contact manner. The waves propagate in the material, and when they encounter a discontinuity (such as a crack) part of the elastic energy is dissipated into heat, primarily through friction [24][25]. Generated heat propagates to the surface where it can be detected by an IR camera.…”

Section: Vibrothermographymentioning

confidence: 99%

Nondestructive Testing of Ceramic Hip Joint Implants with Laser Spot Thermography

Roemer

Pieczonka

Juszczyk

et al. 2017

Archives of Metallurgy and Materials

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T he paper presents an application of laser spot thermography for damage detection in ceramic samples with surface breaking cracks. The measurement technique is an active thermographic approach based on an external heat delivery to a test sample, by means of a laser pulse, and signal acquisition by an infrared camera. Damage detection is based on the analysis of surface temperature distribution near the exciting laser spot. The technique is nondestructive, non-contact and allows for full-field measurements. Surface breaking cracks are a very common type of damage in ceramic materials that are introduced in the manufacturing process or during the service period. This paper briefly discusses theoretical background of laser spot thermography, describes the experimental test rig and signal processing methods involved. Damage detection results obtained with laser spot thermography are compared with reference measurements obtained with vibrothermography. This is a different modality of active thermography, that has been previously proven effective for this type of damage. We demonstrate that both measurement techniques can be effectively used for damage detection and quality control applications of ceramic materials.

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Study of the Heat Generation Mechanism in Acoustic Thermography

Cited by 42 publications

References 2 publications

The sources of heat generation in vibrothermography

The sources of heat generation in vibrothermography

Synthetic Defects for Vibrothermography

Nondestructive Testing of Ceramic Hip Joint Implants with Laser Spot Thermography

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