Stress relieving intrumented steel bar
Stress relieving intrumented steel bar
(OP)
Looking for pointer to the answer to the following.
We manufacture a device which uses a steel bar intrumented with strain guages on two axis to measure load in two directions. The device is stress relieved using heat when it is gauged, however we have found that we need to exercise the axle before the readings remain consistent, particuallarly the 0 point.
Why do we have to exercise the axle ?
Any thoughts pointers would be appreciated.
Regards
Mike Mustard
We manufacture a device which uses a steel bar intrumented with strain guages on two axis to measure load in two directions. The device is stress relieved using heat when it is gauged, however we have found that we need to exercise the axle before the readings remain consistent, particuallarly the 0 point.
Why do we have to exercise the axle ?
Any thoughts pointers would be appreciated.
Regards
Mike Mustard





RE: Stress relieving intrumented steel bar
Bar material?
Prior thermal history?
Test conditions?
RE: Stress relieving intrumented steel bar
Regards,
Cory
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Stress relieving intrumented steel bar
http://www.welding-advisers.com/
RE: Stress relieving intrumented steel bar
Cory is right on with this, concerning local behavior. At low loads there isn't a uniform stress pattern in the part. You haven't loaded it enough to overcome all of the minor local variations in strength and residual stress.
An example is when you want to take very accurated measurements of elastic modulus. You always load the sample in tension to about 1/2 of the yeild, tehn unload to about 10% of yeild, and then re-load. The values from the final loading are much more consistent and accurate.
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Corrosion never sleeps, but it can be managed.
http://www.trenttube.com/Trent/tech_form.htm
RE: Stress relieving intrumented steel bar