Doctoral Dissertations

Abstract

"This dissertation reports the results of an experimental and analytical investigation to determine the thermal contact resistance of several metal specimen pairs using a relatively new pulse technique. Metal specimens were aluminum 2024-T3, aluminum 6061-T6, aluminum 7075-T6, copper 110, stainless steel 304, molybdenum, and Armco iron. Thermal contact resistance was also determined for dissimilar metal specimen pairs of aluminum 6061-T6 - copper 110 and aluminum 7075-T6 - copper 110. Aluminum 7075-T6, copper 110, and stainless steel 304 specimens were tested to determine the variance of contact resistance with time after loading.

Specimens were circular cylindrical disks between .033 and .061 inches thick and .788 inches in diameter. Specimen contacting surfaces were nominally flat and polished to a surface rms roughness of approximately 2 micro-inches. Axial loads were applied from 20.7 to 124.2 psi in a 10 micron (10⁻⁵mm Hg) vacuum and -10°F environment.

Results of the experiments showed that the thermal contact resistance decreased with increasing load, decreased with increasing time after initial loading and that directional effects are probably not a result of differential thermal expansion and the directional effect exists at relatively low interface pressures.

Thermal contact resistance decreased approximately 40 percent for aluminum 2024-TJ and aluminum 6061-T6 specimens. Aluminum 7075-T6 specimens decreased approximately 75 percent in thermal contact resistance over the interface pressure range of 20.7 to 124.2 psi. Molybdenum values of thermal contact resistance closely approximate those of aluminum 2024-TJ and aluminum 6061-T6 with a 62 percent decrease over the same pressure range.

Copper 110 specimen data were approximately 50 percent less than the aluminum 2024-TJ and aluminum 6061-T6 data and decreased about 43 percent over the pressure range tested, while Armco iron and stainless steel data had approximately four and five times the values of thermal contact resistance as those obtained for aluminum 2024-TJ and aluminum 6061-T6 specimens.

Data obtained from experiments to determine the decrease in thermal contact resistance after initial loading indicated approximately 9 to 66 percent decreases in contact resistance variances between thermal contact resistances for directional effects experiments were on the order of 20 percent.

Correlation between aluminum specimen thermal contact resistance data of this and other investigations is discussed "--Abstract, pages ii-iv.

Advisor(s)

Sauer, Harry J., Jr., 1935-2008

Committee Member(s)

Faucett, T. R.
Remington, Charles R., 1924-2013
Penico, Anthony J., 1923-2011
Rigler, A. K.
Chen, T. S.

Department(s)

Mechanical and Aerospace Engineering

Degree Name

Ph. D. in Mechanical Engineering

Publisher

University of Missouri--Rolla

Publication Date

1972

Pagination

x, 98 pages

Note about bibliography

Includes bibliographical references (pages 75-79).

Rights

© 1972 William Edward, Stewart, Jr., All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Subject Headings

Metals -- Thermal conductivityMetals -- Thermal propertiesHeat -- Conduction -- Measurement

Thesis Number

T 2780

Print OCLC #

6036778

Electronic OCLC #

904056455

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