Estimation of Thermal Resistance Field in Layered Materials by Analytical Asymptotic Method

In this paper, the problem of the quantitative characterization of thermal resistance fields in a multilayer sample is addressed by using the classical front face flash method as the thermal excitation and infrared thermography (IRT) as the monitoring sensor. In this challenging problem, the complete inverse processing of a multilayer analytical model is difficult due to the lack of sensitivity of some parameters (layer thickness, depth of thermal resistance, etc.) and the expansive computational iterative processing. For these reasons, the proposed strategy is to use a simple multilayer problem where only one resistive layer is estimated. Moreover, to simplify the inverse processing often based on iterative methods, an asymptotic development method is proposed here. Regarding the thermal signal reconstruction (TSR) methods, the drawback of these methods is the inability to be quantitative. To overcome this problem, the method incorporates a calibration process originating from the complete analytical quadrupole solution to the thermal problem. This analytical knowledge allows self-calibration of the asymptotic method. From this calibration, the quantitative thermal resistance field of a sample can be retrieved with a reasonable accuracy lower than 5%.

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Thermal Performance Measurements of Thermal Interface Materials Using the Laser Flash Method

ASME 2007 InterPACK Conference, Volume 1 ◽

10.1115/ipack2007-33554 ◽

2007 ◽

Author(s):

Vinh Khuu ◽

Michael Osterman ◽

Avram Bar-Cohen ◽

Michael Pecht

Keyword(s):

Thermal Resistance ◽

Thermal Performance ◽

Heat Sink ◽

Composite Structures ◽

Laser Flash ◽

Flash Method ◽

Thermal Interface Materials ◽

Thermal Interface ◽

Layer Composite ◽

Interface Materials

Thermal interface materials are used to reduce the interfacial thermal resistance between contacting surfaces inside electronic packages, such as at the die-heat sink or heat spreader-heat sink interfaces. In this study, the change in thermal performance was measured for elastomeric gap pads, gap fillers, and an adhesive throughout reliability tests. Three-layer composite structures were used to simulate loading conditions encountered by thermal interface materials in actual applications. The thermal resistance of the thermal interface material, including contact and bulk resistance, was calculated using the Lee algorithm, an iterative method that uses properties of the single layers and the 3-layer composite structures, measured using the laser flash method. Test samples were subjected to thermal cycling tests, which induced thermomechanical stresses due to the mismatch in the coefficients of thermal expansion of the dissimilar coupon materials. The thermal resistance measurements from the laser flash showed little change or slight improvement in the thermal performance over the course of temperature cycling. Scanning acoustic microscope images revealed delamination in one group of gap pad samples and cracking in the putty samples.

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Study of the thermal properties of polyester composites loaded with oriented carbon nanofibers using the front-face flash method

Polymer Testing ◽

10.1016/j.polymertesting.2015.12.011 ◽

2016 ◽

Vol 50 ◽

pp. 255-261 ◽

Cited By ~ 3

Author(s):

Nelson W. Pech-May ◽

Caridad Vales-Pinzón ◽

Alejandro Vega-Flick ◽

Ángel Cifuentes ◽

Alberto Oleaga ◽

...

Keyword(s):

Thermal Properties ◽

Carbon Nanofibers ◽

Front Face ◽

Flash Method ◽

Polyester Composites

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Dual mode imaging in mid infrared with thermal signal reconstruction for innovative diagnostics of the “Monocromo” by Leonardo da Vinci

Scientific Reports ◽

10.1038/s41598-021-01837-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Claudia Daffara ◽

Simone Parisotto ◽

Paola Ilaria Mariotti ◽

Dario Ambrosini

Keyword(s):

Da Vinci ◽

Signal Reconstruction ◽

Leonardo Da Vinci ◽

Dual Mode ◽

Infrared Band ◽

Mid Infrared ◽

Full Field ◽

Thermal Signal ◽

Spatial Registration ◽

Fine Resolution

AbstractDual mode imaging in the mid infrared band, a joint use of thermography and quasi-thermal reflectography, was recently proposed as a full field diagnostic tool in cultural heritage. Here we discuss for the first time, to the best of our knowledge, a detailed application of such non destructive technique to the diagnostics of frescoes, with an emphasis on the location of detachments. We also investigate the use of a thermographic method based on TSR (thermal signal reconstruction), in a long pulse stimulus scheme, as well as the spatial registration of thermal images after post-processing analysis to their visible counterpart, so as to obtain a fine resolution diagnostic map. As an exemplar case study, we report about the application of dual mode imaging with a 500 $${\upmu }\hbox {m}$$ μ m pixel size at object plane on the “Monocromo”, a fresco by Leonardo da Vinci located in the Sforza Castle (Milan, Italy). Our technique was used to guide the conservators during the restoration works, opening new perspectives in artwork diagnostics.

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A Quantitative Comparison Among Different Algorithms for Defects Detection on Aluminum with the Pulsed Thermography Technique

Metals ◽

10.3390/met8100859 ◽

2018 ◽

Vol 8 (10) ◽

pp. 859 ◽

Cited By ~ 11

Author(s):

Ester D’Accardi ◽

Davide Palumbo ◽

Rosanna Tamborrino ◽

Umberto Galietti

Keyword(s):

Signal Reconstruction ◽

Principal Component ◽

Time Intervals ◽

Flat Bottom ◽

Pulsed Thermography ◽

Aluminum Specimen ◽

Thermal Signal ◽

Nominal Size ◽

Pulsed Phase Thermography ◽

Non Destructive

Pulsed thermography is commonly used as a non-destructive technique for evaluating defects within materials and components. In the last few years, many algorithms have been developed with the aim to detect defects and different methods have been used for detecting their size and depth. However, only few works in the literature reported a comparison among the different algorithms in terms of the number of detected defects, the time spent in testing and analysis, and the quantitative evaluation of size and depth. In this work, starting from a pulsed thermographic test carried out on an aluminum specimen with twenty flat bottom holes of known nominal size and depth, different algorithms have been used with the aim to obtain a comparison among them in terms of signal to background contrast (SBC) and number of detected defects by analyzing different time intervals. Moreover, the correlation between SBC and the aspect ratio of the defects has been investigated. The algorithms used have been: Pulsed Phase Thermography (PPT), Slope, Correlation Coefficient (R2), Thermal Signal Reconstruction (TSR) and Principal Component Thermography (PCT). The results showed the advantages, disadvantages, and sensitivity of the various thermographic algorithms.

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Interface controlled thermal resistances of ultra-thin chalcogenide-based phase change memory devices

Nature Communications ◽

10.1038/s41467-020-20661-8 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Kiumars Aryana ◽

John T. Gaskins ◽

Joyeeta Nag ◽

Derek A. Stewart ◽

Zhaoqiang Bai ◽

...

Keyword(s):

Thermal Resistance ◽

Phase Change ◽

Data Storage ◽

Phase Change Memory ◽

Interfacial Thermal Resistance ◽

Thermal Excitation ◽

Interfacial Resistance ◽

New Paradigm ◽

Adjacent Layer ◽

Change Memory

AbstractPhase change memory (PCM) is a rapidly growing technology that not only offers advancements in storage-class memories but also enables in-memory data processing to overcome the von Neumann bottleneck. In PCMs, data storage is driven by thermal excitation. However, there is limited research regarding PCM thermal properties at length scales close to the memory cell dimensions. Our work presents a new paradigm to manage thermal transport in memory cells by manipulating the interfacial thermal resistance between the phase change unit and the electrodes without incorporating additional insulating layers. Experimental measurements show a substantial change in interfacial thermal resistance as GST transitions from cubic to hexagonal crystal structure, resulting in a factor of 4 reduction in the effective thermal conductivity. Simulations reveal that interfacial resistance between PCM and its adjacent layer can reduce the reset current for 20 and 120 nm diameter devices by up to ~ 40% and ~ 50%, respectively. These thermal insights present a new opportunity to reduce power and operating currents in PCMs.

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A New Way of Solving Transient Radiative-Conductive Heat Transfer Problems

Journal of Heat Transfer ◽

10.1115/1.2825914 ◽

1998 ◽

Vol 120 (4) ◽

pp. 943-955 ◽

Cited By ~ 36

Author(s):

S. Andre ◽

A. Degiovanni

Keyword(s):

Front Face ◽

Thermal Excitation ◽

Conductive Heat ◽

Inverse Approach ◽

Matrix Transfer Function ◽

Flux Approximation ◽

The Laplace Transform ◽

Finite Medium ◽

Transfer Problems ◽

Semitransparent Layer

One-dimensional transient energy transfer by conduction and radiation is solved for a finite medium. The semitransparent layer emits, absorbs, and scatters radiation (participating medium). The coupled transfer is solved analytically by considering the well-known two-flux approximation, assuming linear transfer and using the Laplace transform. The semitransparent layer can then be modeled by a matrix transfer function. The accuracy of the solution is verified in the case of sharp thermal excitation by a heat pulse on the front face. It is shown that this general model is very accurate for simulating both the limiting cases of purely scattering and purely absorbing media. In the latter case, the same modeling is derived using the kernel substitution technique, and very good agreement is achieved compared with numerical simulations. The resulting computation times are very small, and suggest that such a model can be used in the inverse approach of thermal problems involving semitransparent materials.

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