Electrical Contact Resistance, Thermal Contact Conductance and Elastic Incremental Stiffness for a Cluster of Microcontacts: Asymptotic Modelling

Improving the power handling capability of direct contact RF MEMS switches requires a knowledge of conditions at the contact. This paper models the temperature rise in a direct contact RF MEMS switch, including the effects of electrical and thermal contact resistance. The maximum temperature in the beam is found to depend strongly on the power dissipation at the contact, with almost no contribution from dissipation due to currents in the rest of the switch. Moreover, the maximum temperature is found to exceed the limit for metal softening for a significant range of values of thermal and electrical contact resistance. Since local contact asperity temperature can be hundreds of degrees higher than the bulk material temperature modeled here, these results underscore the importance of understanding and controlling thermal and electrical contact resistance in the switch.

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Paper 2: Surface Topography Effects in the Estimation of Thermal and Electrical Contact Resistance

Proceedings of the Institution of Mechanical Engineers Conference Proceedings ◽

10.1243/pime_conf_1967_182_306_02 ◽

1967 ◽

Vol 182 (11) ◽

pp. 81-91 ◽

Cited By ~ 1

Author(s):

F. C. Yip ◽

J. E. S. Venart

Keyword(s):

Contact Resistance ◽

Surface Topography ◽

Thermal Contact Resistance ◽

Thermal Contact ◽

Electrical Contact ◽

Surface Waviness ◽

Electrical Contact Resistance ◽

Electrical Analogue ◽

Analogue Study ◽

Asperity Distribution

A method of determining the constrictional thermal contact resistance is proposed and discussed. Consideration is given to modelling the simultaneous effects of asperity distribution and roughness, and surface waviness. The resulting general analysis can be applied to any known surface topography in contact with another. Application and comparison utilizing the method are made to the results of an electrical analogue study.

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Characterization of Thermal Contact Resistance in Metal Micro-Textured Thermal Interface Materials Using Electrical Contact Resistance Measurements

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.297-301.1190 ◽

2010 ◽

Vol 297-301 ◽

pp. 1190-1198 ◽

Cited By ~ 2

Author(s):

R. Kempers ◽

A.J. Robinson ◽

A. Lyons

Keyword(s):

Contact Resistance ◽

Thermal Contact Resistance ◽

Thermal Contact ◽

Electrical Contact ◽

Applied Pressure ◽

Thermal Interface Material ◽

Metal Foil ◽

Electrical Contact Resistance ◽

Thermal Interface ◽

Thermally Conductive

A novel Metal Micro-Textured Thermal Interface Material (MMT-TIM) has been developed to address a number of shortcomings in conventional TIMs. This material consists of a thin metal foil with raised micro-scale features that plastically deform under an applied pressure thereby creating a continuous, thermally conductive, path between the mating surfaces. One of the difficulties in experimentally characterizing MMT-TIMs however, is distinguishing the bulk thermal resistance of the MMT-TIM from the thermal contact resistance that exists where it contacts the test apparatus. Since these materials are highly electrically conductive, this study attempts to employ electrical contact resistance measurements to estimate their thermal contact resistance. Tests using flat silver and gold specimens of known bulk thermal conductivity were used to develop a correlation between electrical and thermal contact resistance. This relationship was then employed to estimate the thermal contact resistance of a prototype silver MMT-TIM and indicates the thermal contact resistance accounts for approximately 10% of the measured thermal contact resistance. A number of issues related to this technique are discussed as well as its future outlook.

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Deformation and Solidification of Droplet Impact With Variable Thermal Contact Resistance

Heat Transfer: Volume 3 ◽

10.1115/ht2003-47056 ◽

2003 ◽

Cited By ~ 2

Author(s):

W. Wang ◽

H.-H. Qiu ◽

P. Cheng

Keyword(s):

Numerical Simulation ◽

Contact Resistance ◽

Thermal Contact Resistance ◽

Thermal Contact ◽

Solidification Process ◽

Numerical Results ◽

Thermal Contact Conductance ◽

Contact Conductance ◽

Molten Droplet ◽

Comparison Results

Interfacial thermal contact resistance between the impinging flow of a molten droplet and a substrate, which is qualified by thermal contact conductance, plays an important role in the spreading and solidification of a droplet. In the present study, a simple correlation for the thermal contact conductance in the rapid contact solidification process was developed. With this correlation being directly used in numerical simulation, for the first time, a variable thermal contact resistance was taken into consideration to simulate both the dynamics and phase change responses during a molten droplet impingement. Numerical results were compared with that of the cases when thermal contact resistance was zero or a constant. The changes in spread factor with time and thermal contact conductance indicated that predictions from the computer simulation were sensitive to the values of thermal contact resistance. Experiment was conducted to demonstrate the validity of the present study. Comparison results showed that rather than using a constant average value, better agreement between the experimental and numerical results would be obtained if a variable thermal contact resistance were used in the numerical simulation.

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Three-Dimensional Thermal Model of Resistance Spot Welding in Aluminum

10.1115/imece1999-1094 ◽

1999 ◽

Author(s):

A. A. S. Arefin Kabir ◽

Jamil A. Khan ◽

Kirk Broach

Keyword(s):

Contact Resistance ◽

Phase Change ◽

Weld Pool ◽

Thermal Contact ◽

Thermal Contact Conductance ◽

Work Piece ◽

Contact Conductance ◽

Faying Surface ◽

Surface Contact ◽

Surface Contact Resistance

Abstract A 3-D thermal model for resistance spot welding in aluminum is presented. The numerical model, validated with experimental findings, considers phase change and the associated weld-pool convection. A parametric study is performed to determine the influence of welding features such as faying surface (work-piece contact surface) contact resistance, current, electrode-work-piece surface-thermal-contact-conductance and electrode tip diameter. These parameters have significant effects on the nugget and heat-affected-zone geometry. The phase change morphology, including melting and solidification rates and weld pool dynamics, is also significantly influenced by the parameters studied. The strongest convection was observed at the center of the molten pool in a plane aligned with gravity. Although two prominent convection cells develop, the phase change morphology is not significantly affected due to the short welding time (less than 0.05 seconds) and low fluid velocity (smaller than 1 × 10−2 mm/s). The nugget grows nonlinearly with increasing current and faying surface contact resistance while diminishing with increasing electrode work-piece surface-thermal-contact-conductance. The influence of faying surface contact resistance on nugget size is less than that of the other parameters. Optimum selection of electrode tip diameter provides the best possible nugget. The duration of weld pool existence increases with the increasing current but decreases with the increasing electrode work-piece surface-thermal-contact-conductance.

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Thermal contact resistance (TCR)/thermal contact conductance (TCC)

HEDH Multimedia ◽

10.1615/hedhme.a.000164 ◽

2017 ◽

Author(s):

Harry J. Sauer Jr. ◽

J. W. Sheffield

Keyword(s):

Contact Resistance ◽

Thermal Contact Resistance ◽

Thermal Contact ◽

Thermal Contact Conductance ◽

Contact Conductance

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On the Enhancement of the Thermal Contact Conductance: Effect of Loading History

Journal of Heat Transfer ◽

10.1115/1.521436 ◽

1999 ◽

Vol 122 (1) ◽

pp. 46-49 ◽

Cited By ~ 22

Author(s):

Y. Z. Li ◽

C. V. Madhusudana ◽

E. Leonardi

Keyword(s):

Heat Flow ◽

Contact Resistance ◽

Experimental Work ◽

Thermal Contact Resistance ◽

Thermal Contact ◽

Cost Effective ◽

Thermal Contact Conductance ◽

Loading History ◽

Contact Conductance ◽

Resistance To Heat

A resistance to heat flow exists at the junction of two surfaces. It has long been recognized that there exists a hysteresis effect, that is, the value of thermal contact resistance in the unloading process is less than that in the loading process at the same load. However, little work has been done in utilizing this phenomenon to enhance the thermal contact conductance. The present experimental work investigated the effect of loading history; in particular the number of load cycles and overloading pressure, on the thermal contact conductance. It was found that the value of the thermal contact conductance might be enhanced by up to 51 percent. A cost-effective way of enhancing the contact conductance is suggested. [S0022-1481(00)01601-7]

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Tuning thermal contact conductance at graphene–copper interfaceviasurface nanoengineering

Nanoscale ◽

10.1039/c5nr00564g ◽

2015 ◽

Vol 7 (14) ◽

pp. 6286-6294 ◽

Cited By ~ 49

Author(s):

Yang Hong ◽

Lei Li ◽

Xiao Cheng Zeng ◽

Jingchao Zhang

Keyword(s):

Contact Resistance ◽

Thermal Contact Resistance ◽

Thermal Contact ◽

Thermal Contact Conductance ◽

Contact Conductance

By introducing a surface nanoengineering design at sub-nm level, the thermal contact resistance between graphene and copper is reduced by 17% due to enhanced phonon couplings across the interface.

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