Part 1: Stresses in a Spherical Vessel from Radial Loads Acting on a Pipe
Number of Pages
As a continuation of the computation of the stresses from local loads in a spherical vessel with a rigid cylindrical insert, the more realistic case of a spherical vessel with an inserted tube is investigated for the case that the tube is subjected to a radial load. As shown by the graphs the maximum deflection is considerably increased by the fact that the insert is now flexible, which flexibility is mainly determined by the ratio of the thickness of the spherical shell and the thickness of the tube. The maximum radial bending moment is greatly decreased by the flexibility of the pipe, whereas the tangential bending moment increases to maximum values that may be somewhat higher than the maximum value of the radial moment for a rigid insert. However, if the ratio of the spherical shell thickness to tube thickness is smaller than about 3, the maximum value of the tangential moment does not become larger than the maximum radial moment for the case of it rigid insert. The maximum membrane forces may become higher than those for it rigid insert.
Part 2: Stresses in a Spherical Vessel from External Moments Acting on a Pipe
In addition to the case of a spherical vessel with an inserted pipe subject to a radial load treated in an earlier paper, the case of external moment acting on an inserted pipe is investigated. After deriving the general solution for the displacements of the pipe, considered as a cylindrical shell, the continuity conditions between the vessel and the pipe are established, in order to determine the constants in the general solutions for the deflection and stress function of the spherical vessel.
Part 3: Influence of a Reinforcing Pad on the Stresses in a Spherical Vessel Under Local Loading
This paper deals with a spherical vessel with a reinforcing pad subject to a radial load or external moment acting on a rigid inserted pipe. After deriving the equations from which the deflections, bending moments and membrane forces can be computed for any case, the special case is worked out where the diameter of the reinforcing pad is two times the outer diameter of the pipe and where the total thickness of the pad is two times the thickness of the vessel. The results are presented in graph form. Comparison of these graphs with those presented in WRC 34 show a decrease of the deflection, an increase in bending moment, and a change in the membrane forces due to the presence of the pad.