| Applies To | |||
| Product: | AutoPIPE | ||
| First Affected Version: | 09.04.00 | ||
| Found in Version: | 11.04.00.10 | ||
| Fixed and Released in Version: | |||
| Area: | All | ||
| Severity: | Critical | ||
| Backlog Issue Number: | 984316 |
Behavior
| Severity | 1 - Critical | ||
| First Affected Build | 9.4.0 | ||
| Affected Product | AutoPIPE | ||
| Affected Versions | Advanced and Nuclear | ||
| Program Affected | Yes | ||
| Program Help Affected | No |
Problem Description
Flanges that are inserted on a segment junction/continuation* point may incorrectly use zero values for external forces and
moments for the Load Combination selected in the Flange Check module. This results in stress values that does not include
the effect of external forces and moments, leading to unconservative results.
Note that only ASME Section VIII Div. 2 Flange Analysis Method requires the use of external forces and moments for flange
stress calculations. However, AutoPIPE includes the external forces and moments effects in flange stress calculations for
ASME Section VIII Div. 1 as well as ASME III Appendix IX Flange Design Methods whenever a Load Combination is selected
in Flange Check. ANSI Check Analysis Method is not impacted by this defect.
*A segment junction/continuation point is a point in the model which is shared by two segments. Typically, this is a result
of user inserting a new segment at a point while modeling or splitting an existing segment.
Steps to Repeat
To illustrate this defect, the following scenario can be considered:
Step 1: Create a new ASME B31.3 model with English units
Step 2: On the Segment dialog, insert a new segment A, with first point at A00 and a new pipe data identifier STD24
Step 3: On the Pipe Properties dialog for STD24, enter the following properties:
Nominal Diameter: 24
Schedule: STD
Pipe Material A106-B
Step 4: Press OK on the Operating Pressure & Temperature dialog without changing any data
Step 5: Insert an Anchor on A00 and insert a 20’ run in the X direction to node A01
Step 6: Insert a Flange on A01 with the following properties:
Flange type: WELDNECK
Pressure rating: 150
Step 7: With the cursor at A01, insert a new Segment B, with the Name of first point as A01
Step 8: Insert another 20’ run in the X direction from node A01 to B01
Step 9: Analyze the model and open the Flange Check module changing the following data:
Analysis > Analysis Method: ASME Section VIII Div. 2
Load > Load Combination: Gravity{1}
Flange > Flange Material: SA-106-B
Flange > Flange/Bolt Dimensions: B16-5
Notice that the Bending Moment under the Load tab is correctly updated to 18,902 ft-lb when Load Combination is set to
Gravity{1}.
Step 10: Check the Analyze checkbox under the Analysis tab. Analyze the flange and click on the Show Report button.
Notice that under the section “3.1 Allowable Stresses” Operating Conditions, stress values higher than zero are displayed
for Longitudinal Hub Stress, Radial Flange Stress etc. These stresses are caused by external gravity moments as internal
pressure is set to 0 psi.
Step 11: Click on node A00 and change the segment direction for Segment A [Home > Operations > Segments > Reverse
Segment(s)]. Node A01 should now be the anchor point and A00 contains the flange.
Step 12: Analyze the model again, open the Flange Check module and navigate to Load tab
Notice that the Bending Moment under the Load tab is now displayed as 0 ft-lb.
Step 13: Analyze the flange and click on the Show Report button
Notice that under the section “3.1 Allowable Stresses” Operating Conditions, all stress values are now 0 psi.
Evaluation
Evaluation Criteria
The following considerations are provided to assist in your evaluation of the potential impact of this defect on the results:
Evaluate whether this defect has affected any existing models by considering the criteria below:
1. Was the model created or updated in program version 9.4.0 or later?
2. Were there any flanges in the model with analysis method set to ASME Section VIII Div. 1, ASME Section VIII Div. 2,
or ASME III Appendix XI?
AND
Was any of these flanges present at a segment junction/continuation point?
A 'No' to one or more of the above criteria means that this defect does not affect the model’s results.
Otherwise, some possible mitigation conditions described below should be considered when evaluating the impact of these
defect on the results.
Only ASME Section VIII Div. 2 Flange Analysis Method requires the use of external forces and moments for flange stress
calculations. The use of external forces and moments in flange stress calculations is not mandated by ASME Section VIII Div.
1 and ASME III Appendix IX Flange Design Methods.
Flange Check is a separate module with separate reporting mechanism. If you do not use the Flange Check module for
Flange Design, other AutoPIPE results are not impacted.
Workaround
Reversing one of the connected segments for the segment junction/continuation point may correct the results
OR
Manually enter the correct Force and Moment values in the Flange Check Load tab module by setting the Load Combination
to User. The correct forces and moments values can be extracted from AutoPIPE Forces and Moments report.
Solution
AutoPIPE Flange Check module should display and use the correct forces and moments values at a segment
junction/continuation point. Additionally, to assist in the screening of the models created in previous program versions for
any potential impact by this defect, the program shall automatically examine the model database after opening the model
and generate a report (model name + "_D984316.TXT"), listing the flanges in the model potentially impacted by this defect.
The program shall display the following confirmation message:
“Flanges inserted on a segment junction/continuation point may useincorrect forces and moments for flange stress calculations due toprevious program defect #984316. Would you like to review evaluationreport?”
The contents of the critical error report shall be like the following sample critical error report:
Defect #984316 Evaluation Report---------------------------------Model Name: TEST1Model Version: 09.06.02.06Program Version: 12.01.00.02Report Filename: TEST1_984316.TXT---------------------------------
Flanges that are inserted on a segment junction/continuation point mayuse zero values for external forces and moments for calculating FlangeStresses in the Flange Check Module due to a previous program defect#984316. Please refer to the published defect report for more details,mitigation conditions and instructions. To assist in the screening ofthis model for any potential impact by this defect, program hasexamined the model database and has found that the reported flangestress values for the flanges listed below may be incorrect and shouldbe re-computed using this program version.
After saving this model or running any analysis in this version orlater commercial release versions, this screening will no longer beperformed.
Flange(s) potentially impacted by this defect:----------------------------------------------
Point Name Segment Analysis MethodA00 A ASME Section VIII Div. 2A00 B ASME Section VIII Div. 1B01 C ASME III Appendix IX
Also See:
Critical and High issues released in v.12.00.00
Known Issues in AutoPIPE (Enhancements, defects, etc..)