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# Strain gauge?

i need some help in this homework.

Foil length of strain gauge is L

Resistance of strain gauge is R

Equation is deltaR/R=0.485(deltaL/L)

the strain gauge is given a strain of X%.

The question says to calculate the change in resistance on the strain gauge.

My problem is that i don't understand the X% strain. I'm not asking for answer, just want to know what the X% strain means

## Discussions

Best Answer 7 years ago

"Strain" is simply the proportion of deformation, usually stretch.

So, a strain of 5% means the sample has stretched by 5% of its original length.

7 years ago

When something is Strained

pulledalong ( say the X axis ) it gets longerand thinner causing the resistance to increase.

That is what a strain gauge does and must be calibrated at rest before

measuring a mechanical stress.

I have torque of shaft strain gauge with slip rings to measure torque in a

rotating motor.

A

7 years ago

There are a few formulae on http://en.wikipedia.org/wiki/Strain_gauge

...not sure if they really help since your formula seems to have the factor built in.