Safety factors in structural integrity assessment of components with defects
International Journal of Structural Integrity
ISSN: 1757-9864
Article publication date: 15 November 2013
Abstract
Purpose
The purpose of this paper is to develop basic principles of deterministic structural integrity assessment of a component with a crack- or notch-like defect by including safety factors against fracture and plastic collapse in criteria equations of linear and nonlinear fracture mechanics.
Design/methodology/approach
The safety factors against fracture are calculated by demanding that the applied critical stress should not be less than the yield stress of the material for a component with a crack or a notch of the acceptable size. Structural integrity assessment of the engineering components damaged by crack- or notch-like defects is discussed from view point of the failure assessment diagram (FAD). The methodology of the FAD has been employed for the structural integrity analysis and assessment of acceptable sizes of throw-thickness notch in a plate under tension and surface longitudinal notch-like defects in a pressure vessel.
Findings
Basic equations have been presented to calculate the safety factor against fracture for critical values of the stress intensity factor, crack tip opening displacement (CTOD), the J-integral and the FAD as well as to estimate an acceptable (safe) region for an engineering component with a crack- or notch-like defect of the acceptable size. It was shown that safety factors against fracture depend on both the safety factor against plastic collapse and employed fracture mechanics criterion. The effect of crack/notch tip constraint is incorporated into criteria equations for the calculation of safety factors against fracture.
Originality/value
The deterministic method of fracture mechanics is recommended for structural integrity assessment of a component with a crack- or notch-like defect by including safety factors against fracture and plastic collapse in criteria equations of linear and nonlinear fracture mechanics.
Keywords
Acknowledgements
The author acknowledges the support of the Russian Foundation of Basic Research (Grant No. 10-08-00393-a). Furthermore, the author appreciates the kind help from the reviewers, who provided beneficial suggestions for improving the final version of the manuscript.
Citation
Matvienko, Y. (2013), "Safety factors in structural integrity assessment of components with defects", International Journal of Structural Integrity, Vol. 4 No. 4, pp. 457-476. https://doi.org/10.1108/IJSI-09-2012-0022
Publisher
:Emerald Group Publishing Limited
Copyright © 2013, Emerald Group Publishing Limited