A Photothermal Technique for the Determination of the Thermal
                    Conductance of Interfaces and Cracks

McDonald, Kathleen R.; Dryden, J.R.; Majumdar, Arun; Zok, Frank W.

doi:10.1115/1.521430

Cited by 12 publications

(6 citation statements)

References 25 publications

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“…4,5 The technique utilizes periodic heating at one point on the specimen surface and measurement of the phase lag () of the temperature with respect to the heat input at some other point. The heat source comprises a focused 0.5 W diode laser that is mounted on a precision x-y-z translation stage and modulated sinusoidally using a lock-in amplifier.…”

Section: (1) Materials and Thermal Diffusivity Measurementsmentioning

confidence: 99%

“…In situ measurements are made of both the longitudinal and the transverse diffusivities using a phase-sensitive photothermal technique. 4 Ancillary measurements of crack density and crack opening displacement are used to determine the contributions to the longitudinal thermal resistance due to each crack. Additionally, models for thermal diffusivity of composite materials are used to elucidate the origins of the degradation in both the longitudinal and transverse diffusivities with applied stress.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Matrix Cracks on the Thermal Diffusivity of a Fiber‐Reinforced Ceramic Composite

McDonald

Dryden

Zok

2001

Journal of the American Ceramic Society

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Effects of matrix cracks and the attendant interface debonding and sliding on both the longitudinal and the transverse thermal diffusivities of a unidirectional Nicalon/MAS composite are investigated. The diffusivity measurements are made in situ during tensile testing using a phase-sensitive photothermal technique. The contribution to the longitudinal thermal resistance from each of the cracks is determined from the longitudinal diffusivity along with measurements of crack density. By combining the transverse measurements with the predictions of an effective medium model, the thermal conductance of the interface (characterized by a Biot number) is determined and found to decrease with increasing crack opening displacement, from an initial value of Ϸ1 to Ϸ0.3. This degradation is attributed to the deleterious effects of interface sliding on the thermal conductance. Corroborating evidence of degradation in the interface conductance is obtained from the inferred crack conductances coupled with a unit cell model for a fiber composite containing a periodic array of matrix cracks. Additional notable features of the material behavior include: (i) reductions of Ϸ20% in both the longitudinal and the transverse diffusivities at stresses near the ultimate strength, (ii) almost complete recovery of the longitudinal diffusivity following unloading, and (iii) essentially no change in the transverse diffusivity following unloading. The recovery of the longitudinal diffusivity is attributed to closure of the matrix cracks. By contrast, the degradation in the interface conductance is permanent, as manifest in the lack of recovery of the transverse diffusivity.

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Section: (1) Materials and Thermal Diffusivity Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effects of Matrix Cracks on the Thermal Diffusivity of a Fiber‐Reinforced Ceramic Composite

McDonald

Dryden

Zok

2001

Journal of the American Ceramic Society

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“…A temperature discontinuity was found at the boundary between copper and liquid helium while a heat flux was passing through the interface. So far, the interfacial thermal resistance has been extensively studied using both theoretical models [6][7][8][9][10][11][12][13][14][15][16][17] and experimental methods [18][19][20][21][22][23][24][25][26][27][28]. Relevant theoretical models for the solid-liquid interfacial thermal resistance have been established based on the surface morphology and solid-liquid contact mechanisms.…”

Section: Introductionmentioning

confidence: 99%

Measurement of Interfacial Thermal Resistance at Microstructured Si–water Interface Using Steady State Method

Yu¹,

Nagayama²

2022

Proceedings of International Exchange and Innovation Conference on Engineering &Amp; Sciences (IEICES)

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Interfacial thermal resistance at solid-liquid interface is of great importance for thermal design of electronic devices. However, the quantitative investigation of interfacial thermal resistance is still open for question. In this study, the steady state method based on ASTM-5470 standard was applied to measure the interfacial thermal resistance at the microstructured Si-water interface. The effects of microstructure geometrical parameters on surface wettability and interfacial thermal resistance were studied. The experimental interfacial thermal resistance at the microstructured Siwater interface shows a dependence on the microstructure geometrical parameters, in correspondence with the surface wetting based on the intermediate wetting state theory.

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“…VACNT arrays are applied to the interface between PT and heat sink. Optical transient thermo-reflectance technique [25,33,34] is employed to measure the contact thermal conductance and effective thermal conductivity of the CNT arrays. Moreover, the temperature responses of the device with CNT arrays as TIM according to various input powers are recorded by an infrared camera, and the conversion efficiencies of the device are also characterized simultaneously, compared with the former thermal management solutions of PP membrane at the same driving condition.…”

Section: Introductionmentioning

confidence: 99%

Vertically aligned carbon nanotube arrays as thermal interface material for vibrational structure of piezoelectric transformer

Chen

Feng

et al. 2018

Smart Mater. Struct.

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The application and characterization of thermal interface material (TIM) for vibrational structures is investigated in this paper. The vibrating feature during the operation requires unique solution for its thermal management, since the connection between the device and heat dissipater should be able to conduct heat efficiently and impose minimum constraint onto the vibration simultaneously. As a typical vibrational device, piezoelectric transformers (PTs) are discussed in this paper. The PTs have urgent demands for thermal dissipation since their power conversion efficiency decrease rapidly with the rising temperature. A novel method by applying vertically aligned carbon nanotube (VACNT) arrays to the interface between PT and heat dissipater is presented to enhance the performance of piezoelectric transformers. VACNT arrays are one of the excellent TIMs. It can directly establish thermal contact between two surfaces by van der Waals’ forces. In addition, the unique anisotropic character of CNT arrays provides enough flexibility to accommodate the vibration during the operation. Different configurations of TIMs are compared with each other in this work, including CNT arrays, tape of polypropylene (PP) membrane and without heat transfer structure (HTS). The results indicate that the temperature rise is lowest and the efficiency is highest at the same power density while CNT arrays served as the TIM. Almost no significant fretting and wearing damage occurred on PT electrode surface with CNT arrays TIM even after working continuously for 120 days. Meanwhile, the thermo-physical properties of CNT arrays at contact interface are measured by optical transient thermo-reflectance technique.

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A Photothermal Technique for the Determination of the Thermal Conductance of Interfaces and Cracks

Cited by 12 publications

References 25 publications

Effects of Matrix Cracks on the Thermal Diffusivity of a Fiber‐Reinforced Ceramic Composite

Effects of Matrix Cracks on the Thermal Diffusivity of a Fiber‐Reinforced Ceramic Composite

Measurement of Interfacial Thermal Resistance at Microstructured Si–water Interface Using Steady State Method

Vertically aligned carbon nanotube arrays as thermal interface material for vibrational structure of piezoelectric transformer

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