Stress analysis verification for perforated connectors in cylindrical shells

The analysis method for GB150 relies on these two coefficients, which are data obtained by professors from Tsinghua University through years of experimental work. 1.5 and 3 are derived.

The stress analysis of flanged connections as specified in JB/T 4732 is identical to the analysis of flange openings in the stress analysis method outlined in GB/T 150.3; both are new results developed by Tsinghua University. The selection of the coefficient for K here actually includes a safety margin. To meet the design criterion of the maximum primary and secondary stress intensity required by the structural stability criteria, for joints whose welds have been smoothly polished and inspected, 3Sm can be used as the allowable value when the pipe fittings are not subjected to external loads. However, to ensure a certain safety margin, a more conservative criterion was adopted, which is why the coefficient of 2.6 was chosen. For particularly important pressure vessels, a coefficient of 2.2 is used; this value is derived from numerous tests showing that the dimensionless local thin-film stress intensity of the vast majority of models exceeds 2.2. Therefore, the coefficients 2.2 and 2.6 are adopted as safety factors in the standards.

It seems that the achievements of the 1995 version of 4732 are more advanced than those of ASME.

But in practical engineering applications, when using ANSYS for solid modeling analysis and stress linearization is performed, can the coefficients of 2.2 and 2.6 be adopted to make a determination? Or must it be checked using only the standard coefficients of 1.5 and 3? Thank you.

Which standard system are you using? For equipment designed in accordance with the ASME system, it is necessary to comply with the standards set by ASME ； If it is designed according to national standards, then follow JB/T4732

I think 2.2 and 2.6 are acceptable

The coefficients of 2.2 and 2.6 specified in JB/T 4732 are applicable to openings in cylindrical shells; then are they also used for openings in other parts, such as end caps?

2.2 and 2.6 apply only to openings in cylindrical shells; openings in end caps are governed by 3Sm.

Based on the allowable limits for various stress intensities, the allowable limit for SII is 1.5Sm, while that for SⅣ is 3Sm. For cylindrical shell nozzles, SII is adjusted to 2.2Sm – is this a relaxation of the requirements? Has the requirement to adjust SⅣ to 2.6Sm become stricter? Can it be understood this way? Should it be implemented strictly? Why is a separate stress analysis required for the reinforcement of openings in cylindrical shell nozzles in JB4732 Appendix J, when no limit is specified for the allowable stress intensity? Please give me some advice.