| Applies To | |
| Product(s): | AutoPIPE |
| Version(s): | ALL; |
| Area: | Calculation |
| Date Logged & Current Version | April. 2014 09.06.00.15 |
Problem:
AutoPIPE's (automatic) calculation of the ASD is lower than the hoop stress and that is not possible!
At bend flexural deformation occurs due to thermal/pressure elongation: the bending determines tensile and compressive stress at the pipe section. Together with the hoop stress, Von Mises calculation shall also consider the compressed fiber of the pipe section (as required in the of bending moment definition in section 5, F200, of DNV 2012).
Solution:
Bentley has identified the following issues with DNV 2012 Automatic ASD calculations:
A. AutoPIPE ASD calculations currently does NOT calculate the maximum bending stress (compression or tension) - a fix is currently in progress and will be issued shortly
B. Our interpretation of DNV 2012 requirements is that the bending moments are not intensified for ASD combinations i.e. SIF values are not used for calculating bending moment stresses for all components. After the fix for item a) above, there may still be differences between Von Mises, General Stress, and Automatic ASD calculations owing to SIF values not being used for ASD bending stress calculations.
C. Bentley is investigating the interpretation and use of effective wall force vs. true wall force for calculation of axial stress for ASD calculations. We would welcome any comments or suggestions on its application for ASD.
D. Please refer to workaround under Item #4, "Difference in values of general stress results and user Von mises results".
First Affected version = 09.05.00.19
Fixed in version = 09.06.01.10 and higher
Logged = TFS-91835