Questions regarding the calculation of the unreinforced section at the small end when the semi-apex angle of the conical shell is less than or equal to 45°
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This post was last edited by awangyong1 on 2019-5-19 at 13:42. Clause 5.6.4.4 of GB150 specifies the reinforcement design only for flangeless conical shells under internal pressure with a half-apex angle of 30° or less. However, in the case of conical shells where the half-apex angle is 30° or less, the larger end has flanges while the smaller end does not, what criteria should be used to calculate the reinforcement design for the smaller end of such conical shells? For the edges without folds, isn’t it necessary to take into account the reinforcement area at the junction of the conical shell and the cylinder? GB150 does not provide a method for calculating the reinforcement area for cases where the half apex angle is less than or equal to 45° and there are no folds at the smaller end
GB150 does not provide a method for calculating the reinforcement area for cones with a half-apex angle of 45° or less and without flanges at the smaller end; it does not mean that such calculations are unnecessary. For cones in this range, you can simply add flanges to them
When a reinforced section structure cannot be used, the Q value for the folded-cone shell is determined according to Figure 5-15 in GB/T150.3
Clause 5.6.4.4 specifies that the scope of application is folded-edgeless conical shells with a half-apex angle not exceeding 30 degrees, and covers the stress verification at the junction with the cylinder when internal pressure acts in combination with other axial loads. Cases outside the scope do not apply to this clause.
I’ve thought about your method as well, but what if there are constraints related to the structure (just an assumption), and it’s not possible to use a folded-edge structure for small sections?
Refer to ASME Section VIII-1, Mandatory Appendix 1-5(g); for joints of flangeless cone sections with a half apex angle of 30° or greater, a special design approach is required. Therefore, according to national standards, folding edges are required by default; if they are not present, analysis and design must be carried out in accordance with standard 4732.
Okay, I’ll take a look at the ASME standards, thank you!