Document Type


Date of Award

Spring 5-31-1982

Degree Name

Doctor of Engineering Science in Mechanical Engineering


Mechanical Engineering

First Advisor

Rong-Yaw Chen

Second Advisor

Richard C. Progelhof

Third Advisor

Hans E. Pawel

Fourth Advisor

Manuel Perez

Fifth Advisor

Jui Sheng Hsieh


Three types of surface conditions (plain surface, plain surface with oxidation inhibitor, and toothed surface) and four types of environmental gases (air, nitrogen, hydrogen, and oxygen) were used to study the performance of electrical connectors installed on aluminum conductors. All of the connectors were placed insealed vessels which allowed the desired type of gas to flow at a steady rate. The connectors were then current cycled.

For the connections prepared with plain surfaces, the connectors deteriorated equally fast in air, nitrogen and hydrogen. Only the connectorsexposed to oxygen showed a higher deterioration rate than the others.

Connections prepared withhaving plain surface and oxidation inhibitor were not influenced by air, nitrogen, hydrogen, or oxygen. The deterioration rates for the connections of these groups were generally lower than those with plain surfaces without inhibitor.

The deterioration rates for connectors with toothed surface were found to be the lowest among the groups of connectors tested.

The teeth on the surface of the connector in this study had the configuration of a cone. The transient heat transfer characteristics of the cone-shaped tooth was investigated analytically. On-off heat generation at the cone surface due to contact resistance and heat loss through convection at the cone base were investigated. A control-volume approach was used to formulate the energy equations which were solved by numerical methods.

The study shows that during the heating process the temperature rise of the solid is proportional to the heat generating intensity and inversely proportional to the convective heat transfer coefficient and that the temperature rise decreases with increasing conductivity. The time required to reach steady state is independent of the intensity of the heat generation and decreases with increasing conductivity. The transient temperature distributions along the centerline of the cone, at the apex of the cone, at the center of the cone base and along the circumference of the cone base are presentedgraphically and approximate expressions for them were found. The time required to reacha certain percentage of the steady state temperature was also determined.

During the cooling process the temperature distribution becomes one-dimensional in nature within a very short time. An approximated expression for the apex transient temperature and the time required for cooling were also obtained.

Closed form solutions for one dimensional transient heat transfer in plate, cylinder, and sphere were also derived using an integral method.



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