Welder-optimized CJP-equivalency welds for tubular connections
Tóm tắt
This paper will present the experimental and numerical investigation on the fatigue crack failure at the root of the enhanced partial joint penetration welds in the circular hollow section X-joint specimens subjected to constant-amplitude brace in-plane bending actions. The enhanced partial joint penetration welds, which include a portion of the brace wall as the inherent “back-plate” for the welds, reduce the workmanship requirement on the welding procedure and improve the quality control of the welded joint. This study compares the fatigue crack developments observed at both the weld toe and the weld root in three large-scale X-joint specimens with different post-weld surface treatments. Root cracking does not take place in as-welded tubular X-joint specimens, of which the fatigue life depends on the weld toe failure. In specimens with post-weld grinding treatments to enhance fatigue resistance of the material near the weld toe, however, the finite-length root face triggers the initiation and propagation of fatigue cracks with an applied number of cycles more than that required to initiate a toe crack in the same tubular X-joint. Ultimate strength testing of specimens with large fatigue cracks, and post-test sectioning, reveals that fatigue failure weld-toe fatigue cracks remain more critical than the root cracks.
Tài liệu tham khảo
American Welding Society (1972–2010) Structural welding code—Steel, AWS D1.1/D1.1M
Hobbacher A (2007). Recommendations for Fatigue Design of Welded Joints and Components. IIW document XIII-2151–07/XV-1254–07
Hong JK (2010) Evaluation of weld root failure using battelle structural stress method. Proceedings of the ASME 29th International Conference on Ocean Offshore and Arctic Engineering Conference. Shanghai, China, 6–11 June 2010
Marshall PW (1982a) Connections for welded tubular structures. IIW Houdremont Lecture, Boston
Marshall PW (1982b) Experience-based, fitness-for-purpose ultra-sonic reject criteria for tubular structures. Proceedings of the 2nd International Conference on Welding of Tubular Structures, Boston, USA., 16–17 July, 1984
Marshall PW (1992) Design of welded tubular connections. Elsevier, Amsterdam, ISBN: 0 444 88201 4
Marshall PW, Qian X, Petchdemaneegam Y, Nguyen CT (2012) Root cracking in tubular oints with enhanced partial joint penetration welds. Proceedings of the 14th International Symposium on Tubular Structures, ISTS-14, London, UK, 12–14 September, 2012, pp. 337–344
Marshall PW, Qian X, Petchdemaneegam Y (2010) Fatigue performance of enhanced partial joint penetration welds for tubular joints. Proceedings of the 13th International Symposium on Tubular Structures, ISTS-13, Hong Kong, 15–17 December, 2010. pp. 473–480
Marshall PW et al (2006) Material selection and fracture control for offshore structures. Proc ISOPE, San Francisco
Meneghetti G (2012) The use of peak stresses for fatigue strength assessments of welded lap joints and cover plates with toe and root failures. Eng Fract Mech 89:40–51
Qian X, Marshall PW, Chen Z, Cheong WKD, Petchdemaneegam Y (2009) Partial joint penetration plus welds for tubular joints: fabrication and SCFs. Proceedings of 62nd Annual Assembly and International Conference of International Institute of Welding, Singapore, 12th–17th July 2009
Qian X, Ou Z, Swaddiwudhipong S, Marshall PW (2012) Brittle failure caused by lamellar splitting in a large-scale tubular joint with fatigue cracks. Manuscript submitted to Marine Structures
Qian X, Marshall PW, Petchdemaneegam Y, Nguyen CT (2011) Fatigue behaviour of CHS joints fabricated using enhanced partial joint penetration welds. Proceedings of the ASME 30th International Conference on Ocean, Offshore and Arctic Engineering, OMAE2011, Rotterdam, The Netherlands, 19–24 June, 2011
Schumacher A, Nussbaumer A, Hirt MA (2001) Fatigue behavior of welded circular hollow section (CHS) joints in bridges. Proceedings of 9th the International Symposium of Tubular Structures, Tubular Structures IX, pp. 291–297