ASSESSING FATIGUE ENDURANCE OF PITTED SPECIMENS BY MEANS OF AN INTEGRATED FRACTURE MECHANICS APPROACH

LARROSA N.L.; CHAPETTI, M.D.; AINSWORTH R.A.

Boston

Conferencia; ASME 2015 Pressure Vessels & Piping Conference; 2015

ASME

From an operator/engineering perspective, the correct as-sessment of the severity of corrosion defects (e.g., pits) can haveenormous economic, social and environmental benefits; there-fore the development of a generally applicable and simple to ap-ply procedure for fatigue assessment of key components is recog-nised as a valuable tool, seeking to reduce the current overly con-servative procedures whilst maintaining structural integrity. Thecritical condition for a crack emanating from a pit (pit-to-cracktransition) to start to propagate is analysed in this paper. The pit-crack configuration is re-characterized into that of a hemispheri-cal crack of length equal to the pit depth, and this assumption isanalysed by detailed 3D FEA. A propagation threshold approachis used to estimate the fatigue resistance from intrinsic materialproperties. The proposed approach is validated by comparisonwith experimental results available in the open literatura.