Issues with pipeline span calculation?
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Modeling with a span of 20 meters works, but when it’s changed to 10 meters plus 10 meters with a node in between, that intermediate node doesn’t work. Why? Is it necessary to add intermediate nodes for calculation in large-span modeling?
If you’re not familiar with this industry, listen to the experts’ explanations and take the opportunity to learn a bit*
No need; it’s better if you use an earlier model to show everyone, as that will make analysis easier. It works without adding anything in the middle, but it doesn’t work when something is added. What kind of support are you adding – guiding or sliding? In what direction does the pipe deform? Is it because the deformation is restricted that it doesn’t work?
Problems with the C2 calculation model. The conclusion is that the stress was too high due to an excessively large span. Personally, I think it’s more reliable to add intermediate nodes for large spans.
There are no constraints on adding nodes in the middle; it’s just a matter of calculating the stress once, and if that calculation fails. If no nodes are added, the software does not warn that the span is too large either. After adding nodes, the node positions no longer meet the requirements.
There’s no such thing; you must have done something wrong somewhere.
I’m not sure what industry you’re in. In our power industry, there are formulas for calculating the maximum span; these formulas take into account the deflection of pipes under the effect of gravity. The software doesn’t give any errors when this limit is not exceeded, but the deflection between the two support points becomes too large. You can refer to DLT5054; there are also some software tools for calculating the spacing between pipe supports. The regulations in our power industry are relatively conservative.
The software performs calculations based on nodes; for straight pipes, it does not include nodes between the two support points. Therefore, since you have added an intermediate node and that node results in an error, it means that the deflection requirement has been exceeded. When you don’t apply any loads, this section of the model is ignored; only the forces at the two support points are calculated.
For pipes with a large span, the maximum stress occurs at the midpoint of the span. If there are no nodes in the middle of the model, the software will not calculate the stresses at those intermediate nodes, resulting in distorted calculations. Therefore, for such models, nodes must be added in between to ensure that the results are reliable.
The stress at the mid-span is a certain value; if this stress cannot be accommodated, it indicates that the spacing between the supports and brackets is too large