Questions about the calculation of externally pressurized conical shells (Experts, please help)
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This post was last edited by liushen203 on 2010-3-22 at 13:43; referring to Figure 6-1 (C-1 and C-2) in GB150-1998, how do people choose these values? 1. That is, when calculating the external pressure, how is it determined whether the junction between the conical shell and the cylinder should be considered as a support point? Is it the formula Δ used to determine whether reinforcement is needed at the joint?
I have the same question: what is the basis for determining whether the large or small end of the cone section serves as the supporting line?
Looking forward to an answer; it’s fine to discuss it.
My understanding is as follows: if the line of connection between the cylinder and the conical shell can serve as a support line, it means that there is sufficient moment of inertia at that connection to ensure its stability. In practical calculations, it is generally necessary to check whether the conical shell requires reinforcement, and reinforcement rings are installed when such reinforcement is needed. As for the statement in GB150 that “if the connection point can serve as a support line,” this refers to situations where no reinforcement is required, namely the cases in figures e and f. If reinforcement is required, it corresponds to the c-2 case.
This post was last edited by liushen203 on 2010-3-22 at 17:25. On the third floor, thank you for your answer. Does that mean that when no additional reinforcement is needed at the junction between the conical shell and the cylinder, this junction does not need to be used as a W-support point, as shown in Figure C-2? Otherwise, use it as a support point and reinforce it, as shown in figures b, e, f. And to determine whether reinforcement is needed, should the thickness of the conical shell be calculated using 7-2-5, and the reinforcement area at the joints as well as the inertial distance at those joints taken into account?
I asked our expert on document renewal about this question before, and the answer was that it was translated according to foreign standards; there are no annotations in the original text, so our expert was also unable to provide a clear explanation
5# liushen203, you’ve understood it backwards – there is no need for additional reinforcement at the junction where the conical shell meets the cylinder (note: it’s reinforcement, not repair; the two concepts are different). At that junction, the moment of inertia is already sufficient to ensure the stability of the shell, so that junction can serve as a supporting line. Otherwise, reinforcement is needed; once the reinforcement ring is properly designed, the support line becomes the center line of that ring (note: it is no longer the connection line between the cylinder and the conical shell at this point). As for what you mentioned, the effective reinforcement area can be referred to in GB150 and the \"Training Manual for Pressure Vessel Designers\", while the actual inertial moment of the joints can be found in mechanics of materials. This place is indeed a bit challenging; one needs to understand it well by reading more books.