| Applies To | |
| Product(s): | AutoPIPE |
| Version(s): | All |
| Area: | Trunnion |
| Original Author: | Bentley Technical Support Group |
| Date Logged & Current Version |
July. 2024 24.00.00.231 |
Problem:
How to define in-plane and out-plane User SIF in Vertical and Horizontal Pipe?
Clarify how in-plane and out-plane SIFs are defined and applied for trunnion supported elbows and straight pipe?
Solution:
If we have 2 points defined in a same plane, then we have to refer local axis to understand the In- Plane and Out plane axis at specific node.
We have a horizontal pipe the moment about local z axis (Green colour) will be In-plane bending moment, hence xy local will be In Plane. Similarly, the moment about local y axis (Red colour) will be Out -plane bending moment hence xz local will be Out plane. Refer the screenshot below:
Now we have a vertical pipe the moment about local z axis (Green colour) will be In-plane bending moment, hence xy local will be In Plane. Similarly, the moment about local y axis (Red colour) will be Out -plane bending moment hence xz local will be Out plane. As shown in screenshot below:
Horizontal trunnion:
In case of horizontal trunnion, when we define the SIF in and SIF out at D02 and E02 then we can see the XY is the In plane and XZ is Out plane as per global axis.
Considered the three-test case listed below:
1. SIF In, SIF out at D02 and E02 is set to 1 and override all the SIF and index to 1.
2. SIF In is set to 5, SIF out is set to 1 at D02 and E02 and override all the SIF and index to 1.
3. SIF In is set to 1, SIF out is set to 5 at D02 and E02 and override all the SIF and index to 1.
We can observe from the screenshot below that both the trunnions are bending in XY plane which due to an in plane bending moment same we can see in the code compliance report screenshot below:
Behavior of Autopipe:
1. In first scenario: There is In-Plane bending moment and SIF’s are 1 so there is no impact Thermal expansion stress range.
2. In Second scenario: There is In-Plane bending moment and SIF In is 5 and SIF out 1 so we can see SIF In plane has an impact as per Eq 17 of B31.1 and we can see the increase in thermal expansion stress which is as expected.
3. In Third scenario: There is In-Plane bending moment and SIF In is 1 and SIF out 5 so we can see SIF Out-Plane has no impact as per Eq 17 of B31.1 and we can see the no impact thermal expansion stress which is as expected.
This is the intended behavior of AutoPIPE.
Vertical trunnion:
While in case of vertical trunnion when we define the SIF in and SIF out at B01 then we can see the XY is the Out-Plane and XZ is In-Plane as per global axis.
Considered the three-test case listed below:
1. SIF In, SIF out B01 is set to 1 and override all the SIF and index to 1.
2. SIF In is set to 5, SIF out is set to 1 at B01 and override all the SIF and index to 1.
3. SIF In is set to 1, SIF out is set to 5 at B01 and override all the SIF and index to 1.
We can observe from the screenshot below that both the trunnions are bending in XY plane which due to an OutPlane bending moment same we can see in the code compliance report screenshot below:
Behavior of Autopipe:
1. In first scenario: There is Out-Plane bending moment and SIF’s are 1 so there is no impact Thermal expansion stress range.
2. In Second scenario: There is Out-Plane bending moment and SIF In is 5 and SIF out 1 so we can see SIF In plane has no impact as per Eq 17 and we can see the same thermal expansion stress which is as expected.
3. In Third scenario: There is in Plane bending moment and SIF In is 1 and SIF out 5. So, we can see SIF out plane has an impact as per Eq 17 of B31.1 and we can see the increase in thermal expansion stress which is as expected
This is the intended behavior of AutoPIPE.
See Also
Model Input listing - "TEE" sub-report
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