The CII calculation shows that the thermal stress at the steam pipe elbow reaches 73% – is this result acceptable?
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The CII calculation shows that the thermal stress at the steam pipe elbow reaches 73% – is this result acceptable? I’m at a beginner level; it involves just three simple operating conditions. The calculated secondary stress at the elbow is 73% of the allowable stress. Is this result acceptable for the pipeline layout plan? I wonder what the prescribed upper limit is for project sizes among professionals who are experts in stress analysis? Also, I don’t have the ability to consider various operating conditions and such; for such a simple calculation, shouldn’t it be more conservative? I’ve never worked on stress analysis projects and don’t have any knowledge of engineering concepts. Please advise, experts~{:3_60:}
One more thing to add: when the radial displacement of the support point reaches 300 MM, it seems to me that this is an excessively large radial displacement – it’s not acceptable~{:3_48:}
The secondary stress should not exceed this value; we usually keep it around 80%. Sometimes it’s difficult to adjust it, but 90% is also acceptable. Theoretically, anything below 100% is safe, but there are definitely differences between the actual situation and the design, so it’s better to leave some margin.
Well, that makes sense. For a pipe with such a long straight section of DN900, if the radial displacement of the support reaches 300 mm, is that acceptable?
The magnitude of the displacement isn’t that important; what matters more is whether the pipe supports will fall off the column and whether the pipes will hit anything on the sides. If nothing goes wrong, then it’s fine. But if there is a more optimized solution, the displacement still needs to be controlled.
Well, since our steam pipes are in the trench – there are only two of them – in theory the base plate could be made larger. Of course, in practice it’s not necessarily possible to do that. If we didn’t have to worry about the pipes slipping off the base plate or about insufficient spacing between them, then a DN900 pipe with a radial offset of 300 MM shouldn’t break. . . It seems that displacement does play a role; after all, the pipe isn’t made of rubber, so excessive displacement could cause it to break. Additionally, when we tried to add guides to restrict radial displacement, the thermal stress at the elbow point immediately rose to 80%. . . . . Hurry up and redirect it to {:3_59:}
Design is one thing, but whether construction is carried out according to the plans is another matter; first and foremost, it is necessary to ensure that there are no issues with the design. Steel pipes are flexible pipelines; as long as the secondary stress is not excessive, there will be no problems. 80% is a reasonable value