The influence of multiple axial erosions on a three dimensional crack in determining the fatigue life of autofrettaged pressurized cylinders Article

cited authors

  • Levy, C; Perl, M; Ma, Q

fiu authors

abstract

  • 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 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 and crack ellipticities, a/c = 0.5 - 1.5 emanating from the tip of erosions of different geometry, namely, a) semi-circular erosions of relative depths of 1-10% 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 = 0.3 - 2.0. Erosion separation angle, a, is taken from 12° to 360°. Deep cracks are almost unaffected by the erosion. The effective SIF for relatively short cracks is enhanced by the presence, separation distance and geometry of the erosion, as well as the crack geometry and may result in a significant decrease in the vessel's fatigue life of up to an order of magnitude.

publication date

  • December 1, 2000

start page

  • 55

end page

  • 61

volume

  • 400