Three-Dimensional Stress Analysis for Semi-Elliptical Cracks in the Connection of Cylinder-Hemispherical Head for Thick-Walled Cylindrical Pressure Vessels

Subject Areas : Engineering

H Eskandari ¹ (Abadan Institute of Technology, Petroleum University of Technology, Abadan, Iran)
M Ghanbari ² (Abadan Institute of Technology, Petroleum University of Technology, Abadan, Iran)
F Mirzadeh ³ (Abadan Institute of Technology, Petroleum University of Technology, Abadan, Iran)

Received: 2020-09-01 Accepted : 2020-11-17 Published : 2021-03-30

Keywords: Cylindrical pressure vessel, Stress intensity factor, Semi-Elliptical Crack, Cylinder-hemispherical head,

Abstract :

These pressure vessels are made by different type of heads. One of them is hemi-spherical head. The area of geometrical discontinuity, like the connection of the cylinder to its hemi-spherical head, are the most susceptible areas for crack initiation along their welds. So it is worthwhile to consider cracks located at this connection. The purpose of this article is to investigate the effect of variation of stress field and geometry of problem on distribution of Stress Intensity Factor (SIF) for a semi-elliptical surface crack which is located at the connection of cylinder to its hemispherical head. The three dimensional finite element analysis is performed by employing singular elements along the crack front. The ratio of crack depth to crack length (a/c) ranged from 0.3 to 1.2; the ratio of crack depth to wall thickness (a/t)ranged from 0.2 to 0.8; and the cylinder geometry parameter of vesselranged from 1.2 to 2. For better comparison the results are normalized and reported in non-dimensional formats. The results show that the crack configuration, vessel thickness and radius have significant influence on the stress intensity factor distribution along the crack front. Also For a fixed and the maximum value of SIF occur in the cylindrical part and approximately near the deepest point of crack; not on the deepest point of crack depth and this may be due to changing stress field in this connection. The stress intensity factors are presented in suitable curves for various geometrical configurations providing useful tool for the fracture mechanics design of cracked pressure vessels.

References:

[1] Raju I.S., Newman J.C., 1982, Stress-intensity factors for internal and external surface cracks in cylindrical vessels, Journal of Pressure Vessel Technology 104: 293-298.
[2] Nabavi S.M., Shahani A.R., 2008, Calculation of stress intensity factors for a longitudinal semielliptical crack in a finite-length thick-walled cylinder, Fatigue & Fracture of Engineering Materials & Structures 31: 85-94.
[3] Shiv Sahaya Shukla., Murthy K.S.R.K., 2019, Numerical analysis of a semi-elliptical surface cracked plate under tension, AIP Conference Proceedings.
[4] Slami H., El Had K.H., El Bhilat H., Hachim A., 2019, Numericall analysis of the effect of external circumferential elliptical cracks in transition thickness zone of pressurized pipes using XFEM , Journal of Applied and Computational Mechanics 5(5): 861-874.
[5] Perl M., Matan S., 2019, 3-D stress intensity factors due to full autofrettage for inner radial or coplanar crack arrays and ring cracks in a spherical pressure vessel, Journal of Procedia Structural Integrity 2: 3625-3646.
[6] Zareei A., Nabavi S.M., 2016, Calculation of stress intensity factors for circumferential semi-elliptical cracks with high aspect ratio in pipe, Journal of Pressure Vessels and Piping 146: 32-38.
[7] Lin X.B., Smith R.A., 1997, Stress intensity factors for semi-elliptical internal surface cracks in autofrettaged thick-walled cylinders, Journal of Strain Analysis for Engineering Design 32(5): 351-363.
[8] Guerrero M.A., Betegon C., Belzunce J., 2008, Fracture analysis of a pressure vessel made of high strength steel (HSS), Engineering Failure Analysis 15: 208-219.
[9] Chen J., Pan H., 2013, Stress intensity factor of semi-elliptical surface crack in a cylinder with hoop wrapped composite layer, Journal of Pressure Vessels and Piping 30: 1-5.
[10] Predan J., Mocilnik V., Gubeljak N., 2013, Stress intensity factors for circumferential semi-elliptical surface cracks in a hollow cylinder subjected to pure torsion, Engineering Fracture Mechanics 105: 152-168.
[11] Newman J.C., Raju I.S., 1980, Stress-intensity factors for internal surface cracks in cylindrical pressure-vessels, Journal of Pressure Vessel Technology 102: 342-346.
[12] Kirkhope K.J., Bell R. , Kirkhope J.,1991, Stress intensity factors for single and multiple semi-elliptic surface cracks in pressurized thick-walled cylinders, Journal of Pressure Vessels and Piping 47: 247-257.
[13] Zheng X.J., Glinka G., 1995, Weight functions and stress intensity factors for longitudinal semi-elliptical cracks in thick-wall cylinders, Journal of Pressure Vessel Technology 117: 383-389.
[14] Zheng X.J., Kiciak A., Glinka G., 1997, Weight functions and stress intensity factors for internal surface semi-elliptical crack in thick-walled cylinder, Engineering Fracture Mechanics 58: 207-221.
[15] Perl M., Bernshtein V., 2010, 3-D stress intensity factors for arrays of inner radial lunular or crescentic cracks in a typical spherical pressure vessels, Engineering Fracture Mechanics 77: 535-548.
[16] Valentin G., Arrat D., 1991, Stress intensity factors of semi-elliptical cracks in single- or double-layered spherical shells, Journal of Pressure Vessels and Piping 48(1): 9-20.
[17] Chao Y.J., Chen H., 1989, Stress intensity factors for complete internal and external cracks in spherical shells, Journal of Pressure Vessels and Piping 40(4): 315-326.
[18] Wang B., Hu N., 2000, Study of a spherical shell with a surface crack by the line-spring model, Engineering Structures 22(8): 1006-1012.
[19] Perl M., Bernshtein V., 2011, 3-D stress intensity factors for arrays of inner radial lunular or crescentic cracks in thin and thick spherical pressure vessels, Engineering Fracture Mechanics 78: 1466-1477.
[20] Perl M., Bernshtein V., 2012, Three-dimensional stress intensity factors for ring cracks and arrays of coplanar cracks emanating from the inner surface of a spherical pressure vessel, Engineering Fracture Mechanics 94: 71-84.
[21] Diamantoudis A.T., Labeas G.N., 2005, Stress intensity factors of semi-elliptical surface cracks in pressure vessels by global-local finite element methodology, Engineering Fracture Mechanics 72: 1299-1312.
[22] ANSYS 15.0, 2014, FE Program Package, ANSYS Inc.
[23] Usman T.M., Javed H.M., 2015,The effects of thermal stresses on the elliptical surface cracks in PWR reactor pressure vessel, Theoretical and Applied Fracture Mechanics 75: 124-136.
[24] Raju I.S., Newman J.C., 1979, Stress intensity factors for a wide range of semielliptical surface cracks in finite-thickness plates, Engineering Fracture Mechanics 11: 817-829.
[25] API/A579-1/ASME FFS-1: Fitness –For-Servic, 2007, American Society of Mechanical Engineers.
[26] Köşker S., 2007, Three-Dimensional Mixed Mode Fracture Analysis of Functionally Graded Materials, Master’s Thesis, Middle East Technical University.