Stresses from Locally Applied External Loads

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Most vessels are also subject to loadings at the supports, nozzles, and attachments. These loadings produce deflections, edge rotations, shears, bending moments, and membrane forces. The effect rapidly decreases with the distance from the point of application, where the maximum stress occurs. In practical applications, the number of variables is considerable, and some judgement must […]

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Pressure Vessels Reinforced Openings

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Pressure Vessels Reinforced Openings

Because stresses around openings are higher than the normal design stresses for the plate thickness, additional material must be provided to carry the additional stress in the shell around the opening. The additional material provided is referred to as reinforcement. The basic concept of reinforcement of openings is that the cross-sectional area of material removed […]

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Pressure Vessels Stresses at Openings

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Pressure Vessels Stresses at Openings

All pressure vessels must be provided with openings to get the process fluid in and out, and to provide entry for maintenance and inspection. When a circular opening is made in a plate subjected to uniform tension, a high concentration of stress occurs near the hole, with its maximum value at the edge of the […]

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Pressure Vessels Stress Concentrations

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The normal equations for stresses in pressure vessels are based on the assumption that there is continuous elastic action throughout the member, and that the stress, for simple tension and compression, is uniformly distributed over the entire cross section. Abrupt changes in section geometries, however, can invalidate these assumptions, leading to great irregularities in stress […]

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Concentric Toriconical Reducers Discontinuity Stress

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Concentric Toriconical Reducers Discontinuity Stress

At high pressures (over 150 psi), where discontinuity stresses at the cone-to-cylinder junction can reach values above allowable limits, conical reducers having a knuckle radius at the large cylinder and a flare (reintrant knuckle) at the small end are preferred, as shown in Figure 100-13. Although more expensive to fabricate, toriconical reducers have the advantage […]

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Shell-to-Cone Junction Without Knuckle Discontinuity Stress

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The thickness of a conical head or sections under internal pressure, with a half-apex angle smaller than 30°, is calculated by simple ASME Code membrane-stress equations and the ASME Code rules for reinforcement at the junction. No special analysis of discontinuity stresses is normally required. When, in addition to internal pressure, there are external loads, […]

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Shell-to-Hemispherical Head Junction Discontinuity Stresses

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A hemispherical head is almost always thinner than a cylindrical shell, and, therefore, a structural discontinuity exists at the junction of the head with the shell. This discontinuity stress is negligible, however, when tapered transitions are used. Discontinuity stresses at a hemispherical head-to-shell junction are lower than at the junction of the shell with any […]

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Discontinuities in Cylindrical Shells

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Discontinuities in cylindrical shells occur when the shell is constructed of portions of different thicknesses and/or different materials. If the cylinder is long enough, the effect of the edge forces will dissipate to a small value within short distance, and their overall effect on the shell can be neglected.

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