Reference Type:  Journal Article
Record Number: 1
Author: Lie, S. T., Li , T. and Shao, Y. B.
Year: 2011
Title: Estimation of stress intensity factors in tubular k-joints using direct and indirect methods
Journal: Advanced Steel Construction
Volume: 8
Issue: 1
Pages: 21
Start Page: 17
Short Title: Estimation of stress intensity factors in tubular k-joints using direct and indirect methods
DOI: 10.18057/IJASC.2012.8.1.2
Keywords: Direct method, Indirect method, J-integral method, Mesh generator, Stress intensity factor, Surface crack, Tubular K-joint
Abstract: The stress intensity factors at the deepest point and at the crack ends of a surface crack in a tubular K-joint are calculated by direct and indirect methods. In the direct method, the surface crack is modelled explicitly. An automatic mesh generator is developed to produce a well-graded mesh around the crack region. This is achieved by using five types of elements. Thereafter, the stress intensity factors of a surface crack located anywhere along the weld toe at the joint intersection are calculated using the J-integral method. The computed values had been verified by experimental test results. In the indirect method, the stress intensity factors are estimated by the T-butt solutions used in conjunction with the stress concentration factors (SCFs) and degree of bending (DOB) of the uncracked tubular K-joint. In this study, a total of 1024 models, covering a wide range of geometrical parameters and crack shapes, have been selected and analyzed. Both approaches are able to produce a safe estimation of stress intensity factors at the deepest point of the surface crack. However, the indirect method is found to be extremely conservative; it overestimates the stress intensity factor values by as much as 190.4% (β=0.5, γ=30, τ=0.5, a/T=0.1, c/a=5) at the deepest point, and 390.7% (β=0.4, γ=30, τ=0.5, a/T=0.5, c/a=8) at the crack ends of the surface crack respectively.
Author Address: School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798