Discussion: “The Effects of External Pressure on Thin-Shell Pressure Vessel Heads” (Jones, Jr., Edward O., 1962, ASME J. Eng. Ind., 84, pp. 205–216)

1962 ◽  
Vol 84 (2) ◽  
pp. 218-218
Author(s):  
R. G. Sturm
1962 ◽  
Vol 84 (2) ◽  
pp. 205-216 ◽  
Author(s):  
Edward O. Jones

This paper is concerned primarily with the effects of external pressure on thin-wall torispherical, toriconical, and ellipsoidal pressure vessel heads including the determination of the collapse pressures. Two test vessels, one having torispherical and 120-deg toriconical heads and the other having ellipsoidal and 90-deg toriconical heads, were used in the study. Longitudinal and circumferential stresses per psi external pressure were plotted for the regions at which the vessel heads had been welded to the cylindrical portions of the vessels. Deflection values were plotted for the torispherical and ellipsoidal heads. Both the stress values and deflection values were determined from experimental data.


1986 ◽  
Vol 108 (4) ◽  
pp. 526-529
Author(s):  
A. E. Blach

Half-pipe heating channels are used on the outside of pressure vessels such as agitators, mixers, reactors, etc., to avoid the high external pressure associated with heating jackets. No applicable method of analysis is contained in the ASME Code and proof tests are normally required for registration with governing authorities. An analytical method is presented which permits the evaluation of stresses in shell and half pipe; numerical examples are included.


Author(s):  
Barry Millet ◽  
Kaveh Ebrahimi ◽  
James Lu ◽  
Kenneth Kirkpatrick ◽  
Bryan Mosher

Abstract In the ASME Boiler and Pressure Vessel Code, nozzle reinforcement rules for nozzles attached to shells under external pressure differ from the rules for internal pressure. ASME BPVC Section I, Section VIII Division 1 and Section VIII Division 2 (Pre-2007 Edition) reinforcement rules for external pressure are less stringent than those for internal pressure. The reinforcement rules for external pressure published since the 2007 Edition of ASME BPVC Section VIII Division 2 are more stringent than those for internal pressure. The previous rule only required reinforcement for external pressure to be one-half of the reinforcement required for internal pressure. In the current BPVC Code the required reinforcement is inversely proportional to the allowable compressive stress for the shell under external pressure. Therefore as the allowable drops, the required reinforcement increases. Understandably, the rules for external pressure differ in these two Divisions, but the amount of required reinforcement can be significantly larger. This paper will examine the possible conservatism in the current Division 2 rules as compared to the other Divisions of the BPVC Code and the EN 13445-3. The paper will review the background of each method and provide finite element analyses of several selected nozzles and geometries.


Author(s):  
Yoichi Ishizaki ◽  
Futoshi Yonekawa ◽  
Takeaki Yumoto ◽  
Teppei Suzuki ◽  
Shuji Hijikawa

As widely recognized in the industry, it is important to evaluate the creep damage of an elevated temperature vessel so that the mechanical integrity of the vessel can be achieved through the adequate repair and replacement planning. This is quite straight forward procedure for internal pressure vessels. For an external pressure vessel, it is not easy to assess the creep damage due to the complexity of the creep buckling analysis. Eventually, creep cavity evaluation technique without identifying the correct stress distribution has been used so often. However, due to the uncertainty of the technique itself plus conservative mindset of the inspectors, it tends to leads to an excessive maintenance most of the cases. In order to conduct a reasonable remaining life assessment, it is desirable to use the creep cavity inspection in conjunction with another assessment technique such as FEM creep analysis as stated in API 579-1/ASME FFS-1 10.5.7. In this paper, comprehensive approach with FEM and field inspection such as creep cavity evaluation to reinforce the uncertainty of each method will be demonstrated.


1963 ◽  
Vol 85 (2) ◽  
pp. 195-200
Author(s):  
Edward O. Jones

This paper is concerned primarily with a comparison of experimental and theoretical shell-to-head junction stresses of a thin-shell pressure vessel. The portion of the vessel with which this investigation was concerned was the region at the junction of a two-to-one ellipsoidal head and a cylindrical shell. Both a discussion of the theoretical analysis and a description of the experimental investigation are included in the paper.


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