Dear all, I am new towards strain gauges. Is it possible to use strain gauges to measure thermal expansion of aluminium alloy? Most strain gauges are temperature compensated and they would give low thermal output. If i need to use strain gauges to measure thermal expansion of an object, is there anything which i need to take note of? Thank you.

 

Be careful not to confuse temperature compensation with temperature coefficients.

Also keep in mind that the strain gauge interface (circuitry measuring the gauge) will also suffer from thermal effects, either keep this interface at a constant elevated temperature or keep it outside the temperature chamber (depending on application).

 

You will probably not be able to use them DIRECTLY to observe the thermal expansion since they need intimate contact with the object they measure. A gauge could measure the weight of an assembly and with suitable reference surfaces in the design of the fixture, a test piece could expand thermally and in isolation of the gauge put pressure on a surface set to give upward movement to the fixture and change its weight reading in the gauge

 

I would have thought an appropriately prepared surface with the right glue would yield an adequate bond. Scraping the surface at the edge of the gauge or marking by some other means would show if there is any slippage in the gauge itself during test.

It should be noted that even the right glue will not work if applied incorrectly.

 

Thanks for the replies. I am bonding the constantan strain gauge with epoxy. Most applications for strain gauges is to accurately measure the mechanical strain being applied onto the test material. Any thermal strain due to temperature changes have to be avoided and compensated accordingly. However, if i want to measure this thermal strain accurately, are strain gauges still able to measure this kind of strain. My experiment is giving me rather low thermal output, probably wrong choice of strain gauge. I was thinking if i try using isoelastic strain gauge which responds due to temperature changes, can it measure this thermal strain of aluminium alloy?

 

Have you read "Measurement of Thermal Expansion Coefficient Using Strain Gages"?