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.

Dynamic Stress Intensity Factors for an Inclined Subsurface Crack

1984 ◽  
Vol 51 (4) ◽  
pp. 773-779 ◽  
Author(s):  
W. Lin ◽  
L. M. Keer ◽  
J. D. Achenbach
Keyword(s):  
Free Surface ◽  
Stress Intensity ◽  
Integral Equations ◽  
Stress Intensity Factors ◽  
Wave Equations ◽  
Harmonic Excitation ◽  
Subsurface Crack ◽  
Intensity Factors ◽  
Dynamic Stress Intensity Factors ◽  
Time Harmonic

Stress intensity factors are computed for an inclined subsurface crack in a half space, whose surface is subjected to uniform time-harmonic excitation. The problem is analyzed by determining displacement potentials that satisfy reduced wave equations and specified boundary conditions. The formulation of the problem leads to a system of coupled integral equations for the dislocation densities. The numerical solution of the integral equations leads directly to the stress intensity factors. Curves are presented for the ratios of the elastodynamic and the corresponding elastostatic Mode-I and Mode-II stress intensity factors for various frequencies and various inclinations of the crack with the free surface. For small angles of inclination with the free surface and large crack length-to-depth ratios, strong resonance vibrations of the layer between the crack and the free surface may arise.

An improved method for the determination of mode i stress intensity factors by the experimental method of caustics

1979 ◽  
Vol 14 (3) ◽  
pp. 111-118 ◽  
Author(s):  
P S Theocaris ◽  
N I Ioakimidis
Keyword(s):  
Stress Intensity ◽  
Experimental Method ◽  
Stress Intensity Factors ◽  
Crack Tip ◽  
Point Of View ◽  
Mode I ◽  
Theoretical Point ◽  
Intensity Factors ◽  
Geometrical Properties ◽  
Crack Tips

A modification of the usual way of determining mode I stress intensity factors at crack tips by using the experimental method of caustics is proposed. In accordance with the proposed modification, both principal diameters of an experimentally obtained caustic should be taken into account so that the influence of the part of the stress field behaving like r1/2 near the crack tip is minimized ( r being the polar distance from the crack tip). This modification makes the method of caustics much superior to the photoelastic and interferometric methods for the evaluation of mode I stress intensity factors, not only from the experimental but also from the theoretical point of view. Some interesting geometrical properties of the caustics formed at crack tips are also deduced in this paper.

scholarly journals Friction Effect in a Plane Problem of Punch Acting on A Half-Space Weakened by Cracks

2014 ◽  
Vol 8 (2) ◽  
pp. 107-114
Author(s):  
Adam Tomczyk
Keyword(s):  
Stress Intensity ◽  
Contact Problem ◽  
Half Space ◽  
Singular Integral ◽  
Stress Intensity Factors ◽  
Singular Integral Equations ◽  
Complex Variables ◽  
Intensity Factors ◽  
Straight Crack ◽  
Crack Tips

Abstract This work makes use of singular integral equations method to solve plane contact problem for a half-space containing cracks. This method is based on complex variables. Relationships are presented which help find the contact pressure under the punch and the value of stress intensity factors at the crack tips. A detailed solution is presented for the problem of a punch pressed to the surface of a half-space weakened by a single straight crack. It includes both a situation where the punch has a flat and parabolic base. The influence of friction and the position of the crack on the distribution of the values of stress intensity factors i in the functions of crack length and distance from the contact zone was analyzed in detail.

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