Strain guage question

[roadapple]

I need to measure the negative strain after autofrettage (60,000 psi) of a thick walled vessel.

In the past, I have used special sealing glands to connect the strain gauges to the outside where I could record my data. However, these were expensive and prone to problems.

Would it be viable to:
1) install the strain gauges
2) record the "zero" point
3) disconnect the ohm meter from the strain gauge
4) autofrettage the vessel
5) measure the strain at the new strained condition

Is there anything wrong with my logic?

roadapple

 

[Duwe6]

If you know the response curve for that exact gauge, that would work very well. We do the same thing for our vibration transducers -- attach a bunch, read them monthly.

 

[roadapple]

Not knowing much about strain gauges - why would the response curve be necessary?

Doesn't a particular resistance translate to a particular strain - in this case it would be negative.

 

[EdStainless]

You may need to use multiple SGs in case they get damaged in the process.
How do you calibrate your SG's? This may be problematic with all of the handling.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube