Influence of External Loads on Pressure-Carrying Capacity of Outlet Connections

1973 ◽  
Vol 95 (1) ◽  
pp. 113-120 ◽  
Author(s):  
S. Palusamy ◽  
N. C. Lind
Keyword(s):  
Carrying Capacity ◽  
Pressure Vessels ◽  
Plastic Limit ◽  
Rigid Plastic ◽  
Upper Bound Analysis ◽  
Theoretical Predictions ◽  
Plastic Limit Pressure ◽  
External Loads ◽  
Spherical Pressure ◽  
Bound Analysis

Six experiments were performed on mild steel models which confirm that the presence of external loads (axial force, coplanar moment, and shearing force) lowers the plastic limit pressure-carrying capacity of outlet connections from spherical pressure vessels. Excellent agreement is observed between experimental results and theoretical predictions obtained from lower-bound rigid plastic analysis. Similar agreement with upper bound analysis is obtained in the case of axisymmetric loading.

Limit pressures for spherical vessels with radial branches of differing protrusion lengths

1987 ◽  
Vol 22 (4) ◽  
pp. 209-214 ◽  
Author(s):  
M Robinson ◽  
R Kitching ◽  
C S Lim
Keyword(s):  
Yield Criterion ◽  
Branch Pipe ◽  
Plastic Limit ◽  
Linear Programming Method ◽  
Rigid Plastic ◽  
Design Rules ◽  
Non Linear Programming ◽  
Von Mises ◽  
Plastic Limit Pressure ◽  
Spherical Pressure

The effectiveness of the length by which a radial branch pipe extends within a spherical pressure vessel is discussed with reference to the plastic limit pressure of the vessel and the design rules of BS 5500. Lower bound limit pressures are calculated using a non-linear programming method, the stress resultants being expressed in polynomial form. The material was assumed to be rigid-plastic and to obey the von Mises yield criterion.

Load‐carrying capacity of spherical pressure vessels weakened by butt joints

2001 ◽  
Vol 15 (2) ◽  
pp. 153-157
Author(s):  
V V Erofeev ◽  
M V Shakhmatov ◽  
M V Erofeev ◽  
V V Kovalenko
Keyword(s):  
Carrying Capacity ◽  
Pressure Vessels ◽  
Load Carrying Capacity ◽  
Butt Joints ◽  
Load Carrying ◽  
Spherical Pressure

Plastic Limit Pressures for Neighbouring Radial Nozzles in a Spherical Pressure Vessel

1996 ◽  
Vol 210 (1) ◽  
pp. 75-78
Author(s):  
K Naderan-Tahan ◽  
M Robinson
Keyword(s):  
Carrying Capacity ◽  
Pressure Vessel ◽  
Separation Angle ◽  
Plastic Limit ◽  
Limit Pressure ◽  
Spherical Pressure

Limit pressures have been calculated for the case of two identical flush neighbouring radial nozzles in a spherical pressure vessel. The nozzle and vessel radius and thickness have been kept fixed, but the separation angle 2α has been varied. Four cases have been analysed, including that where the nozzles touch, and the results compared to the value for a single nozzle. For these nozzles very little decrease occurred for any of the α. The effect of displacement on pressure carrying capacity was also investigated and shown to be beneficial, so that limit pressure results may be used with confidence.

Plastic Analysis of Radial Outlets From Spherical Pressure Vessels

1964 ◽  
Vol 86 (2) ◽  
pp. 193-198 ◽  
Author(s):  
N. C. Lind
Keyword(s):  
Static Loading ◽  
Local Deformation ◽  
Pressure Vessels ◽  
Cylindrical Vessel ◽  
Plastic Behavior ◽  
Spherical Vessel ◽  
Rigid Plastic ◽  
Limit Pressure ◽  
Plastic Analysis ◽  
Spherical Pressure

A method is described whereby the limit pressure may be determined for a radial juncture of a cylindrical vessel and a spherical vessel, assuming quasi-rigid plastic behavior. The limit pressure may for mild-steel vessels be interpreted as the pressure causing extensive local deformation at the juncture under static loading conditions.

Experimental Investigation of the Behaviour beyond the Elastic Limit of Flush Nozzles in Cylindrical Pressure Vessels

1966 ◽  
Vol 8 (3) ◽  
pp. 330-354 ◽  
Author(s):  
W. J. Cottam ◽  
S. S. Gill
Keyword(s):  
Elastic Limit ◽  
Empirical Relationship ◽  
Pressure Vessels ◽  
Cylindrical Vessel ◽  
Strain Gauges ◽  
Water Volume ◽  
Plastic Limit ◽  
Design Requirement ◽  
Plastic Limit Pressure ◽  
Outside Diameter

Eleven tests have been carried out on mild steel cylindrical pressure vessels with flush nozzles. The cylindrical vessel was 18-in outside diameter x 3/8-in thick and the nozzles covered a range of outside diameters from 2 1/2 in to 6 in and thicknesses from 1/8 in to 3/8 in. The nozzle-vessel weld was in all cases to B.S. 1500, Fig. 32 e. Two plain cylindrical vessels 18-in o.d. x 3/8-in thick were also tested to establish datum curves for the vessels with nozzles. Clock gauges and strain gauges capable of measuring up to 2 per cent strain were used to measure the strain and change of geometry in the vicinity of the nozzle-cylinder intersection. Measurements were also made of the pumped water volume as the pressure was increased. After pressurizing until the main vessel had yielded the instrumentation was removed and all vessels were tested to rupture. The results do not show a well defined plastic limit pressure as normally understood but it has been possible to define from the experiments a series of pressures for each specimen at which consistent patterns of stress, strain and deflection are evident. One of these pressures is chosen to derive an empirical relationship which can be used in formulating a minimum design requirement.

Upper Bound Analysis of Axisymmetric, Closed-Die Forgings

1981 ◽  
Vol 103 (1) ◽  
pp. 109-112 ◽  
Author(s):  
P. Dadras
Keyword(s):  
Velocity Field ◽  
Upper Bound ◽  
Deformation Zone ◽  
Admissible Velocity ◽  
Upper Bound Analysis ◽  
Die Forging ◽  
Closed Die Forging ◽  
Theoretical Predictions ◽  
Experimental Values ◽  
Bound Analysis

A kinematically admissible velocity field for axisymmetric closed die forging is proposed. The forging power and load are calculated and compared with experimental values. It is found that the theoretical predictions give estimates that are substantially higher than actual loads and powers. Also, the effect of different parameters on the height and shape of the deformation zone is investigated and it is shown that the height is independent of flash thickness and length. The angle of convergence of flow from the die to the flash decreases as the flash thickness is increased.

Approximate Analysis of the Plastic Limit Pressures of Nozzles in Cylindrical Shells

1968 ◽  
Vol 90 (2) ◽  
pp. 171-176 ◽  
Author(s):  
R. L. Cloud ◽  
E. C. Rodabaugh
Keyword(s):  
Velocity Distribution ◽  
Upper Bound ◽  
Cylindrical Shells ◽  
Approximate Analysis ◽  
Plastic Limit ◽  
Single Experiment ◽  
Upper Bound Analysis ◽  
Theoretical Approaches ◽  
Limit Pressure ◽  
Bound Analysis

An estimate of the limit pressure for cylindrical nozzles in cylindrical shells is derived from an upper bound analysis based on an assumed velocity distribution. The analysis is restricted to nozzle/shell diameter ratios of 1/2 or less. Comparisons with other theoretical approaches and the results of a single experiment are shown. Design graphs based on the analysis have been prepared to indicate the amount of nozzle or shell thickening required to make the limit pressure of the nozzle-cylinder structure approximately equal to the yield pressure of the imperforated cylinder.

Stresses at openings in the torispherical end closure of a pressure vessel

1973 ◽  
Vol 8 (3) ◽  
pp. 191-199 ◽  
Author(s):  
R Kitching ◽  
K T Lau
Keyword(s):  
Stress Distribution ◽  
Internal Pressure ◽  
Pressure Vessel ◽  
Elastic Stress ◽  
Pressure Vessels ◽  
Plastic Limit ◽  
Plastic Deformations ◽  
Elastic Stresses ◽  
Pressure Test ◽  
Plastic Limit Pressure

In the design of torispherical heads for cylindrical pressure vessels, it would often be desirable to position openings or branch connections in the vicinity of the toroidal portion of the shell, but from strength considerations it is normal practice to avoid doing so. An 18 inch inside-diameter model vessel of this type, with a nominal inside toroidal radius of 1.25 in was used for making strain and hence stress measurements in the shell due to internal pressure. Four unreinforced openings of 3 inch diameter were placed at different positions in the torispherical end and an elastic stress distribution for the shell around each opening was obtained. Distributions of elastic stresses in the shell were compared for the different opening positions with those in the unpierced shell in the toroidal region. Plastic deformations were measured in an over-pressure test and a plastic limit pressure was estimated.

Sign in / Sign up

Export Citation Format

Share Document