Interface pressure distributions and thermal contact resistance of a bolted joint

2005 ◽  
Vol 461 (2060) ◽  
pp. 2339-2354 ◽  
Author(s):  
M Tirovic ◽  
G.P Voller
Keyword(s):  
Cast Iron ◽  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Conductive Heat ◽  
Bolted Joint ◽  
Interface Pressure ◽  
Pressure Distributions ◽  
Area Of Interest ◽  
Wide Range

The paper studies interface pressure distributions and thermal contact resistance (TCR) of a large automotive bolted joint. The research was initiated by the need to determine accurately conductive heat dissipation from a commercial vehicle disc brake. The main area of interest was the conduction between the grey cast iron disc and the spheroidal graphite cast iron wheel carrier. The bolt clamp forces and interface pressure distributions were investigated theoretically and experimentally. Finite-element analyses and pressure-sensitive paper experiments provided very similar interface pressure distributions. TCR change with interface pressure was studied experimentally, by conducting numerous temperature measurements. The derived linear relationship is of generic nature, enabling the calculation of the TCR for a variety of engineering bolted joints, over a wide range of interface pressures.

Bolted Joint Interface Pressure for Thermal Contact Resistance

1971 ◽  
Vol 38 (2) ◽  
pp. 542-545 ◽  
Author(s):  
T. L. Bradley ◽  
T. J. Lardner ◽  
B. B. Mikic
Keyword(s):  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Three Dimensional ◽  
Joint Interface ◽  
Bolted Joint ◽  
Interface Pressure ◽  
Flat Plates ◽  
Pressure Distributions ◽  
Photoelastic Analysis

One of the parameters needed to calculate the thermal contact resistance across a bolted joint is the interface pressure distribution between the plates of the joint [1, 2]. As part of a study [3] on thermal joint conductance, a three-dimensional photoelastic analysis using the stress freezing technique was used to predict the interface pressure. Nine bolted joint geometries were investigated using smooth flat plates of photoelastic material and equal thickness. The resulting interface pressure distributions which are presented are sufficiently accurate for the calculation of thermal contact resistance.

A Scale Analysis Approach to Thermal Contact Resistance

2003 ◽  
Author(s):  
M. Bahrami ◽  
J. R. Culham ◽  
M. M. Yovanovich
Keyword(s):  
Contact Resistance ◽  
Entire Range ◽  
Thermal Contact Resistance ◽  
Present Model ◽  
Thermal Contact ◽  
Scale Analysis ◽  
Metal Contacts ◽  
Novel Approach ◽  
Wide Range ◽  
Data Points

A new analytical model is developed for predicting thermal contact resistance (TCR) of non-conforming rough contacts of bare solids in a vacuum. Instead of using probability relationships to model the size and number of microcontacts of Gaussian surfaces, a novel approach by employing the “scale analysis methods” is taken. It is shown that the mean size of the microcontacts is proportional to the surface roughness and inversely proportional to the surface asperity slope. A general relationship for determining TCR is derived by superposition of the macro and the effective micro thermal resistances. The present model allows TCR to be predicted over the entire range of non-conforming rough contacts from conforming rough to smooth Hertzian contacts. It is demonstrated that the geometry of heat sources on a half-space for microcontacts is justifiable and that effective micro thermal resistance is not a function of surface curvature. A comparison of the present model with 604 experimental data points, collected by many researchers during the last forty years, shows good agreement for the entire range of TCR. The data covers a wide range of materials, mechanical and thermophysical properties, micro and macro contact geometries, and similar and dissimilar metal contacts.

Finite Element Simulation of the Tightening Process of Bolted Joint With a Bolt Heater

2002 ◽  
Vol 124 (4) ◽  
pp. 457-464 ◽  
Author(s):  
Toshimichi Fukuoka ◽  
Quantuo Xu
Keyword(s):  
Finite Element ◽  
Contact Resistance ◽  
Finite Element Simulation ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Numerical Approach ◽  
Numerical Analyses ◽  
Bolted Joint ◽  
Skilled Workers ◽  
Element Simulation

The tightening operation with a bolt heater has advantages surpassing those of other tightening methods. Currently, a bolt heater is mainly applied to tighten huge bolts that cannot be clamped by other means, and the tightening operation is usually supported by the expertise of skilled workers. In this paper, a numerical approach is presented to aim at a broader use of bolt heater technique by elucidating the tightening mechanism. The effects of thermal contact resistance existing around a bolted joint are taken into account for a better accuracy in the numerical analyses. Based on the numerical results obtained, a series guideline to help the tightening operation when performed by less skilled workers is proposed.

Monitoring of L-Shape Bolted Joint Tightness Using Thermal Contact Resistance

2013 ◽  
Vol 53 (9) ◽  
pp. 1531-1543 ◽  
Author(s):  
M. Jalalpour ◽  
J. J. Kim ◽  
M. M. Reda Taha
Keyword(s):  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Bolted Joint

Modeling Thermal Contact Resistance: A Scale Analysis Approach

2004 ◽  
Vol 126 (6) ◽  
pp. 896-905 ◽  
Author(s):  
M. Bahrami ◽  
J. R. Culham ◽  
M. M. Yovanovich
Keyword(s):  
Contact Resistance ◽  
Contact Pressure ◽  
Thermal Contact Resistance ◽  
Present Model ◽  
Thermal Contact ◽  
Scale Analysis ◽  
Novel Approach ◽  
Wide Range ◽  
Applicable Range ◽  
Data Points

A compact analytical model is developed for predicting thermal contact resistance (TCR) of nonconforming rough contacts of bare solids in a vacuum. Instead of using probability relationships to model the size and number of microcontacts of Gaussian surfaces, a novel approach is taken by employing the “scale analysis method.” It is demonstrated that the geometry of heat sources on a half-space for microcontacts is justifiable for an applicable range of contact pressure. It is shown that the surface curvature and contact pressure distribution have no effect on the effective microthermal resistance. The present model allows TCR to be predicted over the entire range of nonconforming rough contacts from conforming rough to smooth Hertzian contacts. A new nondimensional parameter, i.e., ratio of the macro- over microthermal resistances, is introduced as a criterion to identify three regions of TCR. The present model is compared to collected TCR data for SS304 and showed excellent agreement. Additionally, more than 880 experimental data points, collected by many researchers, are summarized and compared to the present model, and relatively good agreement is observed. The data cover a wide range of materials, mechanical and thermophysical properties, micro- and macrocontact geometries, and similar and dissimilar metal contacts.

A New Model for Constriction Resistance of Rough Contacts between Nominally Flat Surfaces

2011 ◽  
Vol 110-116 ◽  
pp. 977-984
Author(s):  
Jun Feng Peng ◽  
Jun Hong ◽  
Yan Zhuang
Keyword(s):  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Rough Surfaces ◽  
Thermal Contact ◽  
Radial Distance ◽  
Asperity Contact ◽  
Flat Surfaces ◽  
Constriction Resistance ◽  
Nonlinear Curve Fitting ◽  
Wide Range

Thermal contact resistance plays an important role in many domains, such as microelectronics and nuclear reactors. This paper proposes a more comprehensive model for the prediction of constriction resistance of rough contact between nominally flat surfaces in vacuum. Firstly, a 3D geometrical asperity contact model is proposed based on the analysis of the profile of actual engineering surface. In this model, the contact is not simplified as a rough surface contacting with a perfectly smooth surface, but described as two rough surfaces. Oblique contact is considered and the effects of several parameters such as the shape of the asperity, the depth of interference, and the radial distance between the centerlines of the contacting asperities are investigated. Some mathematical derivations for constriction resistance are performed, and a series of numerical simulations are also carried out, covering a wide range of values of these parameters in practice applications. A comprehensive correlation for constriction resistance as a function of these parameters is finally obtained by nonlinear curve fitting, and it is validated through some comparisons and it can be used to predict more accurately the thermal contact resistance between rough surfaces.

Thermal Conductivity and Thermal Contact Resistance of Metal Foams

2009 ◽  
Author(s):  
Ehsan Sadeghi ◽  
Nedjib Djilali ◽  
Majid Bahrami
Keyword(s):  
Thermal Conductivity ◽  
Contact Resistance ◽  
Thermal Contact Resistance ◽  
Metal Foam ◽  
Thermal Contact ◽  
High Surface ◽  
Metal Foams ◽  
Analytical Models ◽  
Cross Sectional ◽  
Wide Range

Unique specifications of metal foams such as relatively low cost, ultra-low density, high surface-area-to-volume ratio, and most importantly, the ability to mix the passing fluid provide them a great potential for a variety of thermal-fluidics applications. In the present study, a compact analytical model for evaluating the effective thermal conductivity of metal foams is developed. The medium structure is represented as orthogonal cylindrical ligaments that are equally spaced and sized. A unit cell is taken to represent the metal foam. The model accounts for varying cross-sectional ligaments which is consistent with microscopic images. A numerical analysis is performed to verify the proposed analytical models. The model predictions are in good agreement with existing experimental data and the present numerical results. A parametric study is then performed to investigate the effects of variation in ligament cross-section geometry, uniformity, and aspect ratio over a wide range of porosities. Moreover, Thermal contact resistance phenomenon is included in the analysis.

The Effect of Thermal Contact Resistance at Porous-Solid Interfaces in Finned Metal Foam Heat Sinks

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Christopher T. DeGroot ◽  
Derek Gateman ◽  
Anthony G. Straatman
Keyword(s):  
Heat Transfer ◽  
Contact Resistance ◽  
Boundary Layers ◽  
Thermal Contact Resistance ◽  
Numerical Study ◽  
Thermal Contact ◽  
Porous Solid ◽  
Heat Sinks ◽  
Wide Range ◽  
The Impact

A numerical study on the effect of thermal contact resistance and its impact on the performance of finned aluminum foam heat sinks has been conducted. Calculations are based on the solution of the volume-averaged mass, momentum, and energy equations under conditions of local thermal nonequilibrium using a finite-volume-based computational fluid dynamics code for conjugate fluid/porous/solid domains. Numerical results have been obtained for a wide range of contact resistances at the porous-solid interfaces, up to the limit of an effectively infinite resistance. As the contact resistance is increased to such high levels, the heat transfer is found to asymptote as conduction into the solid constituent of the foam is completely blocked. Even without conduction into the solid, a convective enhancement is obtained due to the presence of the foam material. It is reasoned that this is due to the thinning of the momentum boundary layers as a result of the presence of the porous material, which acts as a momentum sink. As a result of the thinner boundary layers, the flow speed near the finned surfaces and base is increased, which serves to increase the rate of convection from these surfaces. It is also found that for most reasonable interface materials, such as thermal epoxies, the impact of thermal contact resistance on the heat transfer performance in comparison to that for an ideal bond is small.

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