scholarly journals Interaction between line cracks in an orthotropic layer

2002 ◽  
Vol 29 (1) ◽  
pp. 31-42 ◽  
Author(s):  
Subir Das
Keyword(s):  
Fourier Transform ◽  
Stress Intensity ◽  
Finite Thickness ◽  
Intensity Factors ◽  
Orthotropic Layer ◽  
Finite Hilbert Transform ◽  
Crack Tips ◽  
The Fourier Transform ◽  
Analytical Expressions ◽  
Elastostatic Problem

We deal with the interaction between three coplanar Griffith cracks located symmetrically in the mid plane of an orthotropic layer of finite thickness2h. The Fourier transform technique is used to reduce the elastostatic problem to the solution of a set of integral equations which have been solved by using the finite Hilbert transform technique and Cooke's result. The analytical expressions for the stress intensity factors at the crack tips are obtained for largeh. Numerical values of the interaction effect have been computed for and results show that interaction effects are either shielding or amplification depending on the location of each crack with respect to each other and crack tip spacing as well as the thickness of the layer.

Circumferential Edge Crack in a Cylindrical Cavity

1977 ◽  
Vol 44 (2) ◽  
pp. 250-254 ◽  
Author(s):  
L. M. Keer ◽  
V. K. Luk ◽  
J. M. Freedman
Keyword(s):  
Integral Equation ◽  
Stress Intensity ◽  
Cylindrical Cavity ◽  
Edge Crack ◽  
Numerical Scheme ◽  
Crack Opening ◽  
Integral Transforms ◽  
Intensity Factors ◽  
Physical Quantities ◽  
Elastostatic Problem

The elastostatic problem of a circumferential edge crack in a cylindrical cavity is investigated. The problem is formulated by means of integral transforms and reduced to a singular integral equation. The numerical scheme of Erdogan, Gupta, and Cook is used to obtain the relevant physical quantities and the stress-intensity factors, and crack opening displacements are computed for several values of crack length.

Acousto-elastic measurement of stress and stress intensity factors around crack tips

Ultrasonics ◽  
1983 ◽  
Vol 21 (2) ◽  
pp. 57-64 ◽  
Author(s):  
A.V. Clark ◽  
R.B. Mignogna ◽  
R.J. Sanford
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Intensity Factors ◽  
Crack Tips

A Procedure for Estimating the Stress Intensity Factor of a Flattened Surface Crack at a Nozzle Corner

1979 ◽  
Vol 101 (2) ◽  
pp. 181-183 ◽  
Author(s):  
A. S. Kobayashi ◽  
A. F. Emery ◽  
W. J. Love ◽  
A. Antipas
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Surface Crack ◽  
Finite Thickness ◽  
Normal Stresses ◽  
Intensity Factors ◽  
Qualitative Comparison ◽  
Crack Penetration ◽  
Corner Cracks ◽  
Crack Contour

A flattened surface crack at a nozzle corner is modeled by a segment of a semi-elliptical crack in a finite thickness plate with matching crack contour and crack pressure corresponding to the normal stresses in the uncracked nozzle corner. Lacking other solutions for comparison, a qualitative comparison was made between nondimensionalized stress intensity factors at the deepest crack penetration with those obtained experimentally for similar corner cracks in epoxy models.

Stresses at the Surface of a Flat Three-Dimensional Ellipsoidal Cavity

1976 ◽  
Vol 98 (2) ◽  
pp. 164-172 ◽  
Author(s):  
L. Mirandy ◽  
B. Paul
Keyword(s):  
Stress Intensity ◽  
Applied Stress ◽  
Surface Stress ◽  
Fracture Criterion ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Intensity Factors ◽  
Ellipsoidal Cavity ◽  
Isotropic Elastic Medium ◽  
Analytical Expressions

The stress field associated with a thin ellipsoidal cavity in an isotropic elastic medium with arbitrary tractions at distant boundaries is needed to generalize Griffith’s two-dimensional fracture criterion. Such a solution is given here. It is first formulated for a general ellipsoidal cavity having principal semiaxes a, b, and c, and then it is reduced to the specific case of a “flat” ellipsoid for which a and b are very much greater than c. An explicit solution of the general problem is possible but the results are somewhat unwieldy. The dominant terms of an asymptotic solution for small c/b, however, are shown to provide remarkably simple expressions for the stresses everywhere on the surface of the cavity. The applied normal stress parallel to the c axis and the shears lying in a plane perpendicular to it were found to produce surface stresses proportional to (b/c) × applied stress, with the amplification of other components of applied stress being negligible in comparison. Analytical expressions for the location and magnitude of the maximum surface stress are developed along with stress intensity factors for the elliptical crack (c = 0). Three dimensional effects due to ellipsoidal planform aspect ratio (b/a) and Poisson’s ratio are reported.

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.

Elastodynamic Stress-Intensity Factors for a Crack Near a Free Surface

1981 ◽  
Vol 48 (3) ◽  
pp. 539-542 ◽  
Author(s):  
J. D. Achenbach ◽  
R. J. Brind
Keyword(s):  
Stress Intensity ◽  
Half Space ◽  
Stress Intensity Factors ◽  
Elastic Half Space ◽  
Mode I ◽  
Dimensionless Frequency ◽  
Subsurface Crack ◽  
Intensity Factors ◽  
Time Harmonic ◽  
Crack Tips

Elastodynamic Mode I and Mode II stress-intensity factors are presented for a subsurface crack in an elastic half space. The plane of the crack is normal to the surface of the half space. The half space is subjected to normal and tangential time-harmonic surface tractions. Numerical results show the variation of KI and KII at both crack tips, with the dimensionless frequency and the ratio a/b, where a and b are the distances to the surface from the near and the far crack tips, respectively. The results are compared with corresponding results for a crack in an unbounded solid.

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