A toughness based deformation limit for X- and K-joints under brace axial tension

Abstract

This study reports a deformation limit for the initiation of ductile fracture failure in fatigue-cracked circular hollow section (CHS) X- and K-joints subjected to brace axial tension. The proposed approach sets the deformation limit as the numerically computed crack driving force in a fatigue crack at the hot-spot location in the tubular joint reaches the material fracture toughness measured from standard fracture specimens. The calibration of the numerical procedure predicates on reported numerical computations on the crack driving force and previously published verification study against large-scale CHS X-joints with fatigue generated surface cracks. The development of the deformation limit includes a normalization procedure, which covers a wide range of the geometric parameters and material toughness levels. The lower-bound deformation limits thus developed follow a linear relationship with respect to the crack-depth ratio for both X- and K-joints. Comparison of the predicated deformation limit against experimental on cracked tubular X- and K-joints demonstrates the conservative nature of the proposed deformation limit. The proposed deformation limit, when extrapolated to a zero crack depth, provides an estimate on the deformation limits for intact X- and K-joints under brace axial loads.

Keywords

circular hollow section (CHS) / tubular joint / fracture failure / deformation limit / J-integral

References

[1] Maranian P. Reducing Brittle and Fatigue Failures in Steel Structures. American Society of Civil Engineers Press, 2010

[2] Delatte N J Jr. Beyond Failures – Forensic Case Studies for Civil Engineers. American Society of Civil Engineers Press, 2009

[3] Energo Engineering, Inc.Assessment of fixed offshore platform performance in hurricanes Katrina and Rita. MMS Report, MMS project No. 578, 2007

[4] European Committee for Standardization. Eurocode 3: Design of Steel Structures – Part 1–1: General Rules and Rules for Buildings. 2005

[5] American Institute of Steel Construction. Specification for Structural Steel Building, ANSI/AISC360–10, 2010

[6] Anderson T L. Fracture Mechanics Fundamentals and Applications.Abingdon: 3rd ed. Taylor and Francis 2005

[7] Shen W, Choo Y S. Stress intensity factor for a tubular T-joint with grouted chord. Engineering Structures, 2005, 35: 37–47

[8] Qian X. Stress intensity factors for circular hollow section V-joints with a rack-plate chord.Fatigue & Facture of Engineering Materials & Structures, 2009, 32(1): 61–79

[9] Borges L, Chiew S P, Nussbaumer A, Lee C K. Advanced numerical modeling of cracked tubular K joints: BEM and FEM comparison. Journal of Bridge Engineering, 2012, 17(3): 432–442

[10] Qian X, Dodds R H Jr, Choo Y S. Mode mixity for circular hollow section X joints with weld toe cracks.Journal of offshore Mechanics and Arctic Engineering, 2005, 127(3): 269–279

[11] Chang E, Dover W D. Weight function and stress intensity factor for a semi-elliptical surface saddle crack in a tubular welded joint. Journal of Strain Analysis for Engineering Design, 2005, 40(4): 301–326

[12] Qian X, Dodds R H Jr, Choo Y S. Mode mixity for tubular K-joints with weld toe cracks. Engineering Fracture Mechanics, 2006, 73(10): 1321–1342

[13] Lie S T, Li T, Shao Y B. Plastic collapse load prediction and failure assessment diagram analysis of cracked circular hollow section T-joint and Y-joint.Fatigue & Facture of Engineering Materials & Structures, 2014, 37(3): 314–324

[14] Qian X, Li Y, Ou Z. Ductile tearing assessment of high-strength steel X-joints under in-plane bending. Engineering Failure Analysis, 2013, 28: 176–191

[15] Yang Z M, Lie S T, Gho W M. Failure assessment of cracked square hollow section T-joints. International Journal of Pressure Vessels and Piping, 2007, 84(4): 244–255

[16] Qian X. Failure assessment diagram for circular hollow section X- and K-joints. International Journal of Pressure Vessels and Piping, 2013, 104: 43–56

[17] Yang Z M, Lie S T, Gho W M. Fatigue crack growth analysis of a square hollow section T-joint. Journal of Constructional Steel Research, 2007, 63(9): 1184–1193

[18] Qian X, Nguyen C T, Petchdemaneengam Y, Ou Z, Swaddiwudhipong S, Marshall P W. Fatigue performance of tubular X-joints with PJP plus welds: II – numerical investigation. Journal of Constructional Steel Research, 2013, 89: 252–261

[19] Fathi A, Aghakouchak A A. Prediction of fatigue crack growth rate in welded tubular joints using neural network. International Journal of Fatigue, 2007, 29(2): 261–275

[20] Qian X, Zhang Y, Choo Y S. A load–deformation formulation with fracture representation based on the J–R curve for tubular joints. Engineering Failure Analysis, 2013, 33: 347–366

[21] Qian X, Zhang Y. Translating the material fracture resistance into representations in welded tubular structures. Engineering Fracture Mechanics, 2015, 147: 278–292

[22] Yura J A, Zettlemoyer N, Edwards I F. Ultimate capacity equations for tubular joints. In: Proceedings of 12th Offshore Technology Conference. OTC 3690, 1980

[23] Lu L H, de Winkel G D, Yu Y, Wardenier J. Deformation limit for the ultimate strength of hollow section joints. In: Proceedings of 6th International Symposium of Tubular Structures. Melbourne, Australia, <Date>14–16 Dec </Date> 1994, 341–347

[24] American Petroleum Institute (API). API RP 2A-WSD: Recommended practice for planning, designing and constructing fixed offshore platforms- working stress design. <Date>20th ed</Date>. Washington: API, 2000

[25] Dier A F, Hellan O. A non-linear tubular joint response model for pushover analysis. In: Proceedings of 21st International Conference of Offshore Mechanics and Arctic Engineering. Oslo: ASME, 2002,

[26] Choo Y S, Qian X, Foo K S. Nonlinear analysis of tubular space frame incorporating joint stiffness and strength. In: Proceedings of 10th International Conference on Jackup Platform Design. London; City University London, 2005,

[27] Ahmed A, Qian X. A toughness based deformation limit for fatigue cracked X-joints under in-plane bending. Marine Structures, 2015, 42: 33–52

[28] Ahmed A, Qian X. A deformation limit based on failure assessment diagram for fatigue-cracked X-joints under in-plane bending. Ships Offshore Structures, 2014, doi:10.1080/17445302.2014.974297.

[29] Ramberg W, Osgood W R. Description of stress-strain curves by three parameters. Technical note No. 902. Washington: National Advisory Committee for Aeronautics, 1943

[30] American Society of Testing and Materials (ASTMs) International, Standard test method for measurement of fracture toughness.ASTM E1820–15.2015.

[31] Qian X, Petchdemaneengam Y, Swaddiwudhipong S, Marshall P, Ou Z, Nguyen C T. Fatigue performance of tubular X-joints with PJP+ welds: I – experimental study. Journal of Constructional Steel Research, 2013, 90: 49–59

[32] American Welding Society (AWS). AWS D1.1/D1.1M:2010: Structural Welding Code – Steel. <Date>22nd ed</Date>. Miami: Aws, 2010

[33] Qian X, Dodds R H Jr, Choo Y S. Elastic-plastic crack driving force for tubular K-joints with mismatched welds. Engineering Structures, 2007, 29(6): 865–879

[34] Qian X, Romeijin A, Wardenier J, Choo Y S. An automatic FE mesh generator for CHS tubular joints. In: Proceedings of 12th International Offshore and Polar Engineering Conference. 2002, 4: 11–18

[35] Quest Integrity Group Pte. Ltd. FEA Crack 3D Finite Element Software for Cracks, Version 3.2, User’s Manual. 2011

[36] Gullerud A S, Koppenhoefer K, Roy A, RoyChowdhury S, Walters M, Bichon B, Cochran K, Carlyle A, Dodds R H Jr. WARP3D: 3-D dynamic nonlinear fracture analysis of solids using parallel computers and workstations. Structural Research Series (SRS) 607 UILU-ENG-95–2012. Illinois: University of Illinois at Urbana Champaign, 2011

[37] Qian X, Jitpairod K, Marshall P W, Swaddiwudhipong S, Ou Z, Zhang Y, Pradana M R. Fatigue and residual strength of concrete-filled tubular X-joints with full capacity welds. Journal of Constructional Steel Research, 2014, 100: 21–35

[38] Qian X, Petchdemaneengam Y, Swaddiwudhipong S, Marshall P, Ou Z, Nguyen C T. Fatigue performance of tubular X-joints with PJP+ welds: I – experimental study. Journal of Constructional Steel Research, 2013, 90: 49–59

[39] Qian X, Swaddiwudhipong S, Nguyen C T, Petchdemaneengam Y, Marshall P, Ou Z. Overload effect on the fatigue crack propagation in large-scale tubular joint. Fatigue & Facture of Engineering Materials & Structures, 2013, 36(5): 427–438

[40] Zhang Y, Qian X. An eta-approach to evaluate the elastic-plastic energy release rate for weld-toe cracks in tubular K-joints. Engineering Structures, 2013, 51: 88–98

[41] Qian X. Failure assessment diagrams for circular hollow section X- and K-joints. International Journal of Pressure Vessels and Piping, 2013, 104: 43–56

[42] Choo Y S, Qian X, Wardenier J. Effects of boundary conditions and chord stresses on static strength of thick-walled CHS K-joints. Journal of Constructional Steel Research, 2006, 62(4): 316–328

[43] Bowness D, Lee M. Fatigue crack curvature under the weld toe in an offshore tubular joint. International Journal of Fatigue, 1998, 20(6): 481–490

[44] Shih C F, Moran B, Nakamura T. Energy release rate along a three dimensional crack front in a thermally stressed body. International Journal of Fracture, 1986, 30: 79–102

[45] Zhang Y. Nonlinear joint representation in pushover analysis of offshore structures. Dissertation for the Doctoral Degree, Singapore: National University of Singapore, 2013

[46] ABAQUS. ABAQUS/Standard: User’s manual. Hibbitt, Karlsson & Sorensen, 2012

[47] Ahmed A, Qian X. Effect of chord length on the fracture deformation limit for fatigue-cracked X joints under in-plane bending. In: Proceedings of 26th KKHTCNN Symposium. Singapore. KKHTCNN, 2013

[48] Health and Safety Executive. Statics strength of cracked tubular joints: new data and models. Offshore technology report, OTO 1999/054. 1999

[49] Health and Safety Executive. The static strength of cracked joints and tubular members. Offshore Technology Report, 2001/080. 2001

[50] Health and Safety Executive. The ultimate strength of Cracked Tubular K-Joints. Offshore Technology Report, OTH 497. 1997

RIGHTS & PERMISSIONS

Higher Education Press and Springer-Verlag Berlin Heidelberg