I’d like to ask the experts: if local stress calculations using NOZZLEPRO show that it’s acceptable for a large opening on the cover, does that mean the structure is also satisfactory after reinforcing the opening?
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Large openings on the head are not suitable for calculating the reinforcement required due to those openings using the equal area method and analysis methods specified in GBT150. If the local stress at the pipe opening in that area is found to be within acceptable limits when calculated using NOZZLEPRO or FEPipe, does that mean the reinforcement required for that opening is also sufficient? Is it no longer necessary to use finite element analysis separately for opening reinforcement?
If the local stresses calculated using NOZZLEPRO or FEPipe are within acceptable limits, it means that the opening reinforcement under the load at that pipe end meets the design requirements. However, this does not mean that hole reinforcement will be effective under all operating conditions and loading scenarios. To more accurately evaluate the effectiveness of opening reinforcement, it is recommended to conduct finite element analysis, especially in load-bearing and critical areas. This ensures that the openings for reinforcement can withstand the expected loads, and that the structure maintains its stability and safety under various operating conditions. Therefore, the results obtained solely from NOZZLEPRO or FEPipe cannot completely replace finite element analysis. .
If it exceeds the opening ratio range, it can be made into a conical shell； If the opening ratio is within the allowable range, adjust the wall thickness of the head and fittings.
Thank you for the reply. Changing it to a conical shell is one option, but I want to know what the regulations are for using FEA calculations without changing it to a conical shell, as asked in the question.
The provisions for local structural stress analysis are given in Appendix E of GB/T 150.1
Thank you for the advice. It makes sense; if it’s confirmed that there are no other loading conditions on that pipe connection, then perhaps a separate finite element analysis isn’t necessary. After all, most manufacturers don’t have the capability or the software to carry out such analyses.
Under normal circumstances, as long as the calculations are successful, whether they are performed using models (formulas) or through analytical methods, it can be considered that the reinforcement of that pipe fitting is satisfactory. The only thing to note is that the user or the reviewing party must approve the results obtained from those models or analytical calculations. After all, some users or reviewers don’t have the necessary software or technical personnel to verify it; thus, they specify a calculation method.