Learn about PASS/START-PROF pipe stress analysis software
This example demonstrates stub-in analysis for a 219×6 branch pipe (1-8) connecting to a 630×8 main pipeline (10-9) when the main piping design is unknown or under development by another team.
Sample project: Stub-in.ctp
Cutting the piping after node 8 creates significant modeling errors.
a) Node 8 moves freely along the X-axis, which is unrealistic since it connects to the main pipe
b) Main pipe thermal expansion along the Y-axis is not transmitted to node 8
This model produces artificially low stresses and support loads at node 1.
Sample project: Stub-in-Anchor.ctp
Add a fixed anchor at node 8 to restrict X-axis movement. Apply Y-axis displacement of 125 mm (α×ΔT×L = 1.25e-5×200°C×50 m) to simulate main pipe thermal expansion.
This model reveals high stresses exceeding allowable limits. Increase leg 5-4 to 3.5 meters to resolve.
After extending leg 5-4 to 3.5 m, stresses fall within allowable limits.
Sample project: Stub-in-Anchor2.ctp
Sample project: Stub-in-Tee.ctp
Add main pipe segment 10-9 with tee at node B. Fix node 9 with an anchor and add a guide at node 10 to restrict X-axis movement.
Analysis reveals high tee stresses at node 8 that were not visible in previous models.
Sample project: Stub-in-Real.ctp
The most accurate approach models the complete system with main pipeline and stub-in. Results closely match Model 3, validating the partial modeling approach for practical use.
