The Dynamic, Steady-State Propagation of an Antiplane Shear Crack in a General Linearly Viscoelastic Layer

In a previous paper, the dynamic, steady-state propagation of a semi-infinite antiplane shear crack was considered for an infinite, general linearly viscoelastic body. Under the assumptions that the shear modulus is a positive, nonincreasing continuous and convex function of time, convenient, closed-form expressions were derived for the stress intensity factor and for the entire stress distribution ahead of and in the plane of the advancing crack. The solution was shown to have a simple, universal dependence on the shear modulus and crack speed from which qualitative and quantitative information can readily be gleaned. Here, the corresponding problem for a general, linearly viscoelastic layer is solved. An infinite series representation for the stress intensity factor is derived, each term of which can be calculated recursively in closed form. As before, a simple universal dependence on crack speed and material properties is exhibited.

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Plastic Stress Intensity Factors for Small Scale Yielding in Antiplane Shear by Caustics

Journal of Applied Mechanics ◽

10.1115/1.3162613 ◽

1982 ◽

Vol 49 (4) ◽

pp. 754-760 ◽

Cited By ~ 7

Author(s):

P. S. Theocaris ◽

C. I. Razem

Keyword(s):

Stress Intensity Factor ◽

Stress Intensity ◽

Intensity Factor ◽

Crack Tip ◽

Antiplane Shear ◽

Elastic Behavior ◽

Small Scale ◽

Small Scale Yielding ◽

Scale Yielding ◽

Plastic Stress

The KIII-stress intensity factor in an edge-cracked plate submitted to antiplane shear may be evaluated by the reflected caustic created around the crack tip, provided that a purely elastic behavior exists at the crack tip [1]. For a work-hardening, elastic-plastic material, when stresses at the vicinity of the crack tip exceed the yield limit of the material, the new shape of caustic differs substantially from the corresponding shape of the elastic solution. In this paper the shape and size of the caustics created at the tip of the crack, when small-scale yielding is established in the vicinity of the crack tip, were studied, based on a closed-form solution introduced by Rice [2]. The plastic stress intensity factor may be evaluated from the dimensions of the plastic caustic. Experimental evidence with cracked plates made of opaque materials, like steel, corroborated the results of the theory.

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Analysis of a Curved Interfacial Crack Between Viscoelastic Foam and Anisotropic Composites Under Antiplane Shear

International Journal of Modern Physics B ◽

10.1142/s0217979203019344 ◽

2003 ◽

Vol 17 (08n09) ◽

pp. 1573-1579

Author(s):

Heoung Jae Chun ◽

Sang Hyun Park

Keyword(s):

Stress Intensity Factor ◽

Stress Intensity ◽

Composite Materials ◽

Intensity Factor ◽

Hilbert Problem ◽

Crack Problem ◽

Interfacial Crack ◽

Shear Loading ◽

Antiplane Shear ◽

Stiffness Coefficients

The analysis of curved interfacial crack between viscoelastic foam and anisotropic composites was conducted under antiplane shear loading applied at infinity. In the analysis, in order to represent viscoelastic behavior of foam, the Kelvin-Maxwell model was incorporated and Laplace transform was applied to treat the viscoelastic characteristics of foam. The curved interfacial crack problem was reduced to a Hilbert problem and a closed-form asymptotic solution was derived. The stress intensity factors in the vicinity of the interfacial crack tip were predicted by considering both anisotropic characteristics of composites and viscoelastic properties of foam. It was found from the analysis that the stress intensity factor was governed by material properties such as shear modulus and relaxation time, and increased with the increase in the curvature as well as the ratio of stiffness coefficients of composite materials. It was also observed that the effect of fiber orientation in the composite materials on the stress intensity factor decreased with the increase in the difference in stiffness coefficients between foam and composite.

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Stress Intensity Factors of Various Surface Cracks Inside a Hollow Cylinder Under Steady State Thermal Striping

Journal of Pressure Vessel Technology ◽

10.1115/1.3109978 ◽

2009 ◽

Vol 131 (3) ◽

Author(s):

Toshiyuki Meshii ◽

Kentaro Shibata

Keyword(s):

Stress Intensity Factor ◽

Thermal Stress ◽

Steady State ◽

Stress Intensity ◽

Intensity Factor ◽

Hollow Cylinder ◽

Crack Depth ◽

Surface Cracks ◽

Paris Law ◽

Thermal Striping

A thermal stress problem of a long hollow cylinder was considered in this paper. The outer surface of the cylinder was adiabatically insulated, and the inner surface was heated axisymmetrically by a fluid with sinusoidal temperature fluctuations (hereafter called as thermal striping), whose temperature amplitude (ΔT) and angular velocity (ω) were constant. The heat transfer coefficient h was also assumed to be constant. The stress intensity factor (SIF) due to the thermal stress for a given cylinder configuration varies not only with these three parameters ΔT, ω, and h, but also with time. The temperature and, as a result, SIF fluctuation amplitude soon became constant (Meshii, T., and Watanabe, K., 2004, “Stress Intensity Factor of a Circumferential Crack in a Thick-Walled Cylinder Under Thermal Striping,” ASME J. Pressure Vessel Technol., 126(2), pp. 157–162), which hereafter is called as steady state. If one is interested in fatigue crack growth (assuming Paris law) under this thermal stress, because the SIF range soon converges to a constant, it seemed important to know the maximum value of the steady state SIF range for a given cylinder configuration, for all possible combinations of ΔT, ω, and h. This maximum SIF evaluation is time consuming. Thus in this paper, this maximum steady state SIF range for four typical surface cracks’ deepest point, inside a hollow cylinder for all possible combinations of ΔT, ω, and h were presented as a first step. Thin-to thick-walled cylinders in the range of mean radius to wall thickness parameter rm/W=10.5–1 were considered. Crack configurations considered were 360 deg continuous circumferential, radial, semi-elliptical in the circumferential and radial directions. Normalized crack depth for all cases was in the range of a/W=0.1–0.5. In case of semi-elliptical crack, the normalized crack length a/c was all in the range of 0.063–1.

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Simplified Evaluation Method of a Steady State Stress Intensity Factor Range Upper Limit for a Circumferential Crack in a Cylinder

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A ◽

10.1299/kikaia.72.127 ◽

2006 ◽

Vol 72 (713) ◽

pp. 127-132

Author(s):

Toshiyuki MESHII ◽

Kentaro SHIBATA ◽

Katsuhiko WATANABE

Keyword(s):

Stress Intensity Factor ◽

Steady State ◽

Stress Intensity ◽

Intensity Factor ◽

Evaluation Method ◽

Stress Intensity Factor Range ◽

Upper Limit ◽

Circumferential Crack ◽

State Stress

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Determination of the Stress Intensity Factor for a Transverse Shear Crack in a Beam Specimen

Materials Science ◽

10.1007/s11003-014-9710-y ◽

2014 ◽

Vol 50 (2) ◽

pp. 212-216 ◽

Cited By ~ 1

Author(s):

P. S. Kun ◽

S. T. Shtayura ◽

T. M. Lenkovs’kyi

Keyword(s):

Stress Intensity Factor ◽

Stress Intensity ◽

Intensity Factor ◽

Transverse Shear ◽

Shear Crack ◽

Beam Specimen

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Dynamic Emission of Dislocations From a Moving Crack

Journal of Engineering Materials and Technology ◽

10.1115/1.3225819 ◽

1985 ◽

Vol 107 (4) ◽

pp. 277-281 ◽

Cited By ~ 7

Author(s):

Rui-Huan Zhao ◽

J. C. M. Li

Keyword(s):

Stress Intensity Factor ◽

Steady State ◽

Stress Intensity ◽

Intensity Factor ◽

Applied Stress ◽

Critical Stress ◽

Crack Velocity ◽

Plastic Zone Size ◽

Critical Stress Intensity Factor ◽

Dislocation Emission

The emission of dislocations from a propagating crack in the mode II or III situations is studied by computer simulation. While the crack is moving the steady state number of dislocations is smaller than the saturation number which could be emitted from a stationary crack and such a steady state number decreases with increasing crack velocity. The effect on the emission process of the applied stress, the lattice friction for dislocation motion and the critical stress intensity factor for dislocation emission is studied. The results include also the plastic zone size, the dislocation distribution, the dislocation-free zone, and the instantaneous crack velocity. The average crack velocity does not depend on the applied stress but depends only on the critical stress intensity factor for dislocation emission. When such a factor is zero as assumed in some theories, the crack does not move at all.

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