1、 Bulletin on Stability Design of Cylindrical ShellsAPI BULLETIN 2UTHIRD EDITION, JUNE 2004Bulletin on Stability Design of Cylindrical ShellsUpstream SegmentAPI BULLETIN 2UTHIRD EDITION, JUNE 2004SPECIAL NOTESAPI publications necessarily address problems of a general nature. With respect to partic-ul
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13、N.W., Washington, D.C. 20005.Copyright 2004 American Petroleum InstituteFOREWORDThis Bulletin is under jurisdiction of the API Subcommittee on Offshore Structures.This Bulletin contains semi-empirical formulations for evaluating the buckling strength ofstiffened and unstiffened cylindrical shells. U
14、sed in conjunction with API RP 2T or otherapplicable codes and standards, this Bulletin will be helpful to engineers involved in thedesign of offshore structures which include large diameter stiffened or unstiffened cylinders.The buckling formulations and design considerations contained herein are b
15、ased on clas-sical buckling formulations, the latest available test data, and analytical studies. This thirdedition of the Bulletin provides buckling formulations and design considerations based onclassical buckling solutions. It also incorporates user experience and feedback from users. Itis intend
16、ed for design and/or review of large diameter cylindrical shells, typically identifiedas those with D/t ratios greater than or equal to 300. Equations are provided for the predic-tion of stresses at which typical modes of buckling failures occur for unstiffened and stiff-ened cylindrical shells, fro
17、m which the design of the shell plate and the stiffeners may bedeveloped. Used in conjunction with API RP 2T or other applicable codes and standards, thisBulletin will be helpful to engineers involved in the design of offshore structures that includelarge diameter unstiffened and stiffened cylindric
18、al shells.API publications may be used by anyone desiring to do so. Every effort has been made bythe Institute to assure the accuracy and reliability of the data contained in them; however, theInstitute makes no representation, warranty, or guarantee in connection with this publicationand hereby exp
19、ressly disclaims any liability or responsibility for loss or damage resultingfrom its use or for the violation of any federal, state, or municipal regulation with which thispublication may conflict.Suggested revisions are invited and should be submitted to API, Standards Department,1220 L Street, NW
20、, Washington, DC 20005iiiCONTENTS Page Nomenclature 1 Glossary.5 SECTION 1General Provisions.8 1.1 Scope .8 1.2 Limitations.8 1.3 Stress Components for Stability Analysis and Design 9 1.4 Structural Shape and Plate Specifications .9 1.5 Hierarchical Order and Interaction of Buckling Modes 9 SECTION
21、2Geometries, Failure Modes, and Loads .10 2.1 Geometries.10 2.2 Failure Modes10 2.3 Loads and Load Combinations10 SECTION 3Buckling Design Method.15 SECTION 4Predicted Shell Buckling Stresses for Axial Load, Bending and External Pressure .18 4.1 Local Buckling of Unstiffened or Ring Stiffened Cylind
22、ers .18 4.2 General Instability of Ring Stiffened Cylinders 21 4.3 Local Buckling of Stringer Stiffened or Ring and Stringer Stiffened Cylinders .22 4.4 Bay Instability of Stringers Stiffened or Ring and Stringer Stiffened Cylinders, and General Instability of Ring and String Stiffened Cylinders Bas
23、ed Upon Orthotropic Shell Theory 23 4.5 Bay Instability of Stringer Stiffened and Ring and Stringer Stiffened Cylinders-Alternate Method.28 SECTION 5Plasticity Reduction Factors 32 SECTION 6Predicted Shell Buckling Stresses for Combined Loads33 6.1 General Load Cases.33 6.2 Axial Tension, Bending an
24、d Hoop Compression 33 6.3 Axial Compression, Bending and Hoop Compression 34 SECTION 7Stiffener Requirements 36 7.1 Hierarchy Checks 36 7.2 Stiffener Stresses and Buckling.37 7.3 Stiffener Arrangement and Sizes.38 SECTION 8Column Buckling.40 8.1 Elastic Column Buckling Stresses.40 8.2 Inelastic Colu
25、mn Buckling Stresses 40 SECTION 9Allowable Stresses.41 9.1 Allowable Stresses for Shell Buckling Mode41 9.2 Allowable Stresses for Column Buckling Mode .43 SECTION 10Tolerances44 10.1 Maximum Differences in Cross-Sectional Diameters .44 10.2 Local Deviation from Straight Line Along a Meridian .44 10
26、.3 Local Deviation from True Circle .44 10.4 Plate Stiffeners 44 SECTION 11Stress Calculations.46 11.1 Axial Stresses 46 11.2 Bending Stresses46 11.3 Hoop Stresses 47 SECTION 12References .51 APPENDIX ACommentary on Stability Design of Cylindrical Shells .53 INTRODUCTION54 C1 General Provisions 54 C
27、2 Geometries, Failure Modes and Loads 55 C3 Buckling Design Method.56 C4 Predicted Shell Buckling Stresses for Axial Load, Bending and External Pressure58 C5 Plasticity Reduction Factors78 C6 Predicted Shell Buckling Stresses for Combined Loads .80 C7 Stiffener Requirements98 C8 Column Buckling 100
28、C9 Allowable Stresses 101 C10 Tolerances .101 C11 Stress Calculations 104 C12 References .113 APPENDIX BExample - Ring Stiffened Cylinders 118 APPENDIX CExample - Ring and Stringer Stiffened Cylinders128 Tables 3.1 Section Numbers Relating to Buckling Modes for Different Shell Geometries16 6.2-1 Str
29、ess Distribution Factors, Kij 35 C11.3-1 Shell Hoop Stresses and Stress Ratios at Mid Panel for a Range of Cylindrical Shell Configurations111 C11.3-2 Ring Hoop Stresses and Stress Ratios for a Range of Cylindrical Shell Configurations.112 Figures 2.1 Geometry of Cylinder12 2.2 Geometry of Stiffener
30、s 13 2.3 Shell Buckling Modes for Cylinders .14 3.1 Flow Chart for Meeting API Recommendations .17 7.2-1 Design Lateral Load for Tripping Bracket 39 10.3-1 Maximum Possible Deviation e from a True Circular Form .45 10.3-2 Maximum Arc Length for Determining Plus or Minus Deviation.45 C.4.1.1-1 Test f
31、xcL/Fyversus API FxcL/FyRing Stiffened Cylindrical Shells Under Axial Compression61 C.4.1.1-2 Test fxcL/API FxcLVersus MxRing Stiffened Cylindrical Shells Under Axial Compression62 C.4.1.2-1 Test fcL/Fy versus API FcL/FyRing Stiffened Cylindrical Shells Under External Pressure 64 C.4.2.2-2 Test fcL/
32、API FcLversus MxRing Stiffened Cylindrical Shells Under External Pressure .65 C.4.3.1-1 Test fcL/Fy versus FcL/FyRing and Stringer Stiffened Cylindrical Shells Under Axial Compression .69 C.4.3.1-2 Test fxcL/API FxcLversus MQ Ring and Stringer Stiffened Cylindrical Shells Under Axial Compression .70
33、 C.4.3.2-1 Test fcL/Fyversus API FcL/Fy Ring and Stringer Stiffened Cylindrical Shells Under External Pressure72 C.4.3.2-2 Test fcL/API FcLversus MxRing and Stringer Stiffened Cylindrical Shells Under External Pressure73 C.4.5.2-1 Comparison of Test Pressures with Predicted Failure Pressures for Str
34、inger Stiffened Cylinders79 C.5-1 Comparison of Plasticity Reduction Factor Equations81 C.6.1-1 Comparison of Test Data from Fabricated Cylinders Under Combined Axial Tension and Hoop Compression with Interaction Curves (Fy= 36 ksi) 82 6.1-2 Comparison of Test Data from Fabricated Cylinders Under Co
35、mbined Axial Tension and Hoop Compression with Interaction Curves (Fy= 50 ksi) 83 6.2-1 Comparison of Test Data with Interaction Equation for Unstiffened Cylinders Under Combined Axial Compression and Hoop Compression .85 6.2-2 Comparison of Test Data with Interaction Equation for Ring Stiffened Cyl
36、inders Under Combined Axial Compression and Hoop Compression .86 6.2-3 Comparison of Test Data with Interaction Equation for Ring Stiffened Cylinders Under Combined Axial Compression and Hoop Compression .87 6.2-4 Comparison of Test Data with Interaction Equation for Local Buckling of Ring and Strin
37、ger Stiffened Cylinders Under Combined Axial Compression and Hoop Compression88 6.2-5 Comparison Test Data with Interaction Equation for Local Buckling of Ring and Stringer Stiffened Cylinders Under Combined Axial Compression and Hoop Compression89 6.2-6 Comparison of Test Data with Interaction Equa
38、tion for Bay Instability of Ring and Stringer Stiffened Cylinders Under Combined Axial Compression and Hoop Compression90 6.2-7 Comparison of Test Data with Interaction Equation for Bay Instability of Ring and Stringer Stiffened Cylinders Under Combined Axial Compression and Hoop Compression91 C.6.2
39、-8 Local Instability of Ring Stiffened Cylindrical Shells Subject to Combined Loading- Four Series by Chen et al for D/t longitudinal, circumferential or shear. Bulletin 2U-Bulletin on Stability Design of Cylindrical Shells 6 maximum shear stress theory: Failure theory defined by the following equat
40、ion: 1- 2= Fywhere 1is the maximum principal stress and 2, is the minimum principal stress, with tension positive and compression negative. orthogonally stiffened: A member with circumferential (ring) and longitudinal (stringer) stiffeners. radial pressure: Uniform external pressure acting only on t
41、he sides of a member. residual stresses: The stresses that remain in an unloaded member after it has been formed and installed in a structure. Some typical causes are forming, welding and corrections for misalignment during installation in the structure. The misalignment stresses are not accounted f
42、or by the plasticity reduction factor . ring stiffened: A member with circumferential stiffeners. shell panel: That portion of a shell which is bounded by two adjacent rings in the longitudinal direction and two adjacent stringers in the circumferential direction. slenderness ratio (KLt/r): The rati
43、o of the effective length of a member to the radius of gyration of the member. stress relieved: The residual stresses are significantly reduced by post weld heat treatment. stringer stiffened: A member with longitudinal stiffeners. yield stress: The yield stress of the material determined in accorda
44、nce with ASTM A307. Bulletin 2U-Bulletin on Stability Design of Cylindrical Shells 7 SECTION 1General Provisions 1.1 SCOPE 1.1.1 This Bulletin provides stability criteria for determining the structural adequacy against buckling of large diameter circular cylindrical members when subjected to axial l
45、oad, bending, shear and external pressure acting independently or in combination. The cylinders may be unstiffened, longitudinally stiffened, ring stiffened or stiffened with both longitudinal and ring stiffeners. Research and development work leading to the preparation and issue of all three editio
46、ns of this Bulletin is documented in References 1 through 16 and the Commentary. 1.1.2 The buckling capacities of the cylinders are based on linear bifurcation (classical) analyses reduced by capacity reduction factors which account for the effects of imperfections and nonlinearity in geometry and b
47、oundary conditions and by plasticity reduction factors which account for nonlinearity in material properties. The reduction factors were determined from tests conducted on fabricated steel cylinders. The plasticity reduction factors include the effects of residual stresses resulting from the fabrica
48、tion process. 1.1.3 Fabricated cylinders are produced by butt-welding together cold or hot formed plate materials. Long fabricated cylinders are generally made by butt-welding together a series of short sections, commonly referred to as cans, with the longitudinal welds rotated between the cans. Lon
49、g fabricated cylinders generally have D/t ratios less than 300 and are covered by AP RP 2A. 1.2 LIMITATIONS 1.2.1 The criteria given are for stiffened cylinders with uniform thickness between ring stiffeners or for unstiffened cylinders of uniform thickness. All shell penetrations must be properly reinforced. The results of experimental studies on buckling of shells with reinforced openings and some design guidance are given in Ref. 2. The stability criteria of this bulletin may be used for cylinders with openings that are reinforced in accordance with th
