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Residual stress measurement in pipelines
- Thread starter usecheijk
- Start date
LittleInch
Petroleum
To paraphrase the great John McEnroe "Are you serious"??
First of why do want to measure "residual stress" It appears absolutely nowhere in any design code or calculation.
Second why do possibly think drilling a hole in a pipeline is even a vaguely good idea.
I despair sometimes......
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
First of why do want to measure "residual stress" It appears absolutely nowhere in any design code or calculation.
Second why do possibly think drilling a hole in a pipeline is even a vaguely good idea.
I despair sometimes......
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
- Thread starter
- #5
Thanks to your for your answers.
Yes! hole-drilling method in live pipelines!. Check these cases:
Yes! hole-drilling method in live pipelines!. Check these cases:
- Thread starter
- #6
Thank you for your answers.
Yes!, hole-drilling method for residual stress in live pipelines. Check these cases:
What do you think?
Yes!, hole-drilling method for residual stress in live pipelines. Check these cases:
What do you think?
Usecheijk:
What do you expect to prove by trying to measure residual stresses in an operating pipe line? What problems are you having and what problems are you trying to solve by doing this type of testing? Why not explain the nature of what you are really trying to do or prove, and discuss that a bit, so you get some feedback on the significance of the perceived problem. Please explain what stresses you will actually be measuring when you do the hole drilling/strain gaging method of testing for stresses at a point. Don’t forget, unless you unload the pipe, and test at ambient temps., you will also have a whole bunch of other combined stresses involved at any point on the pipe. What do you expect these various combined stresses to be, irrespective of whatever the residual stresses are or might be, their magnitudes, orientations, etc? Show some sketches of the pipe plan and elevation, etc, along with all significant loads and dimensions, etc. We just had a thread within the last couple weeks on residual stresses in piping, namely, thread378-402720. It might be interesting for you to review that thread.
What do you expect to prove by trying to measure residual stresses in an operating pipe line? What problems are you having and what problems are you trying to solve by doing this type of testing? Why not explain the nature of what you are really trying to do or prove, and discuss that a bit, so you get some feedback on the significance of the perceived problem. Please explain what stresses you will actually be measuring when you do the hole drilling/strain gaging method of testing for stresses at a point. Don’t forget, unless you unload the pipe, and test at ambient temps., you will also have a whole bunch of other combined stresses involved at any point on the pipe. What do you expect these various combined stresses to be, irrespective of whatever the residual stresses are or might be, their magnitudes, orientations, etc? Show some sketches of the pipe plan and elevation, etc, along with all significant loads and dimensions, etc. We just had a thread within the last couple weeks on residual stresses in piping, namely, thread378-402720. It might be interesting for you to review that thread.
- Thread starter
- #8
LittleInch
Petroleum
Ok,
You weren't being very precise here. By "hole drilling", what you seem to mean is a small hole drilled to a depth of 10 to 20% of the wall thickness from what I can gather while you very accurately measure the change in strain around the "hole". Perhaps you need to find out how deep someone intends to drill the "hole" and what diameter it is.
They don't seem to say what happens to the "hole" or indentation after the measurement, but It's either left there or filled in I assume.
I've read a couple of your references and still can't work out what purpose it is finding this information. Buried pipelines have lots of stresses, but making suitable allowance for them is part of design. I can't understand why you need to know.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
You weren't being very precise here. By "hole drilling", what you seem to mean is a small hole drilled to a depth of 10 to 20% of the wall thickness from what I can gather while you very accurately measure the change in strain around the "hole". Perhaps you need to find out how deep someone intends to drill the "hole" and what diameter it is.
They don't seem to say what happens to the "hole" or indentation after the measurement, but It's either left there or filled in I assume.
I've read a couple of your references and still can't work out what purpose it is finding this information. Buried pipelines have lots of stresses, but making suitable allowance for them is part of design. I can't understand why you need to know.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
I have long heard of the "hole drilling method" for residual stress measurement, but had not heard it applied to working pipelines (I guess I'm not exactly sure how one would prove how much of the stress was "residual" and how much due to whatever "working" was/had been going on?)
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