Using thermal Expansion

[Darcom]

Just need a little help finding a body or an object that benefits from thermal expansion. I know the obvious ones like the bimetallic strip and thermostats / thermometers. Its difficult to find uses for it when it causes so many engineering problems. Any suggestions would be appreciated.

Steven Dark

 

[IRstuff]

Thermal expansion can be used to compensate for things that have effectively negative temperature coefficients. Many optical telescopes are "passively" athermalized, wherein the designer uses a single material, aluminum for the housing to ensure matched thermal expansion and to compensate for the index of refraction changes in the optics over temperature.

Certain materials are engineered to provide matched thermal expansion with other system components. Invar was regularly used in crygenic systems containing glass, as it had the closest thermal match to glass, thus minimizing any thermal stresses at the glass/metal interface. TTFN