Stress intensity factors for an embedded elliptical crack in a plate of finite thickness

1997 ◽  
Vol 120 (1-4) ◽  
pp. 127-140
Author(s):  
D. S. Lee
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Finite Thickness ◽  
Elliptical Crack ◽  
Intensity Factors

scholarly journals Influence Coefficients to Calculate Stress Intensity Factors for an Elliptical Crack in a Plate

2002 ◽  
Author(s):  
Patrick Le Delliou ◽  
Bruno Barthelet
Keyword(s):  
Finite Element ◽  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Atomic Energy Commission ◽  
Finite Thickness ◽  
Elliptical Crack ◽  
Intensity Factors ◽  
Normal Loading ◽  
Influence Coefficients ◽  
Wide Range

Crack assessment in engineering structures relies first on accurate evaluation of the stress intensity factors. In recent years, a large work has been conducted in France by the Atomic Energy Commission to develop influence coefficients for surface cracks in pipes. However, the problem of embedded cracks in plates (and pipes) which is also of practical importance has not received so much attention. Presently, solutions for elliptical cracks are available either in infinite solid with a polynomial distribution of normal loading or in plate, but restricted to constant or linearly varying tension. This paper presents the work conducted at EDF R&D to obtain influence coefficients for plates containing an elliptical crack with a wide range of the parameters: relative size (2a/t ratio), shape (a/c ratio) and crack eccentricity (2e/t ratio where e is the distance from the center of the ellipse to the plate mid plane). These coefficients were developed through extensive 3D finite element calculations: 200 geometrical configurations were modeled, each containing from 18000 to 26000 nodes. The limiting case of the tunnel crack (a/c = 0) was also analyzed with 2D finite element calculation (50 geometrical configurations). The accuracy of the results was checked by comparison with analytical solutions for infinite solids and, when possible, with solutions for finite-thickness plates (generally loaded in constant tension). These solutions will be introduced in the RSE-M Code that provides rules and requirements for in-service inspection of French PWR components.

scholarly journals Weight Function Approach for Semi Elliptical Crack at Blade Mounting Locations in Steam Turbine Rotor System

2018 ◽  
Vol 62 (3) ◽  
pp. 203-208
Author(s):  
Damarla Kiran Prasad ◽  
Kavuluri Venkata Ramana ◽  
Nalluri Mohan Rao
Keyword(s):  
Stress Intensity ◽  
Weight Function ◽  
Steam Turbine ◽  
Stress Intensity Factors ◽  
Turbine Rotor ◽  
Rotor System ◽  
Elliptical Crack ◽  
Influence Coefficient ◽  
Intensity Factors ◽  
Steam Turbine Rotor

This paper presents analysis of stress intensity factors at blade mounting locations of steam turbine rotor system. General expressions for the stresses induced in a rotating disc are derived and these equations are applied to steam turbine rotor disc. It is observed that the radial stress increases instantly at blade mounting location which indicates the probability of crack initiation and growth. A semi elliptical crack is considered at that location and weight function approach is used to determine the stress intensity factors. The results are validated with the influence coefficient approach. The differences of present approach with influence coefficient approach are less than 3 %. Hence the present approach is suitable for determination of stress intensity factors in a semi elliptical crack at blade mounting locations of a steam turbine rotor disc.

Inner and Outer Cracks in Internally Pressurized Cylinders

1977 ◽  
Vol 99 (1) ◽  
pp. 83-89 ◽  
Author(s):  
A. S. Kobayashi ◽  
N. Polvanich ◽  
A. F. Emery ◽  
W. J. Love
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Finite Thickness ◽  
Internal Surface ◽  
Surface Cracks ◽  
Single Edge ◽  
Intensity Factors ◽  
Curvature Effects ◽  
Aspect Ratios ◽  
Dimensional Finite Element

Stress intensity factors of pressurized surface cracks at the internal surface and un-pressurized surface cracks at the external surface of an internally pressurized cylinder are estimated from stress intensity factors of a semi-elliptical crack in a finite-thickness flat plate. Curvature effects of the cylinder are determined by comparing two-dimensional finite element solutions of fixed-grip, single edge-notched plates and single edge-notched cylinders. Stress intensity factors for semi-elliptical cracks with crack aspect ratios of b/a = 0.2 and 0.98 at crack depths up to 80 percent of the cylindrical wall thickness are shown for internally pressurized cylinders with outer to inner diameter ratios, Ro/Ri, ranging from 10:9 to 5:4 for outer surface cracks and to 3:2 for inner surface cracks.

Sign in / Sign up

Export Citation Format

Share Document