THERMAL CONDUCTANCE OF LAP-JOINTS IN VACUUM
Abstract
Experiments on the thermal conductance, in vacuum, of lap-jointed specimens of aluminium-clad L72, and unclad L70, aluminium alloys (4% Cu; 0.7% Si; 0.7% Mn) are described. The specimens were strips of thin sheet fastened with rivets, or nuts and bolts. The effects of variability of riveting technique, temperature, thermal cycling, overlap area, bolting-torque, burrs, and interlayers of paint, anti-corrosive jointing compound, indium and electrical insulators were studied. In general, the results support a mechanism of high heat transfer, by metallic conduction, near the rivets or bolts only. This hypothesis is discussed, and it is suggested that the thermal behavior of the specimens is described better in terms of an additional length of heat-conduction path than by a conventional heat transfer coefficient. It was found, if burrs are removed, that both careful bolt-tightening and standard, aircraft-construction, riveting techniques produce thermally good lap-joints for which the effect of the doubled thickness is equal to, or greater than, the opposing effect of the interfacial thermal resistance.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1966
- Accession Number
- AD0637770
Entities
People
- A. B. Osborn
- W. N. Mair
Organizations
- Royal Aircraft Establishment