Erosion geometry effects on the mode I stress intensity factor (SIF) for a crack emanating from an erosion's deepest point in a multiply eroded, autofrettaged, pressurized, thick-walled cylinder are investigated. The problem is simulated as a two-dimensional problem and is solved via the FEM method. Autofrettage, based on von Mises yield criterion, is simulated by thermal loading and SIFs are determined by the nodal displacement method. SIFs are evaluated for a variety of relative crack lengths, ao/t = 0.01 - 0.45 emanating from the tip of erosions of different geometries, namely, a) semi-circular erosions of relative depths of 110% of the cylinder's wall thickness, t; b) arc erosions for several dimensionless radii of curvature, r′/t = 0.05 - 0.4; and c) semi-elliptical erosions with ellipticities of d/h 0.5-1.5, and erosion separation angle, α, from 12° to 360°. Deep cracks are almost unaffected by the erosion, the effective SW for relatively short cracks is found to be enhanced by the presence, separation distance and geometry of the erosion that may result in a significant decrease in the vessel's fatigue life of up to an order of magnitude.
|Number of pages||6|
|Journal||American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP|
|State||Published - 1 Dec 1999|
|Event||Computer Technology - 1999 (The ASME Pressure Vessels and Piping Conference) - Boston, MA, USA|
Duration: 1 Aug 1999 → 5 Aug 1999