Stress intensity factors for curved cracks obtained with the displacement discontinuity method

1988 ◽  
Vol 37 (2) ◽  
pp. R31-R34
Author(s):  
Richard A. Schultz
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Displacement Discontinuity ◽  
Displacement Discontinuity Method ◽  
Intensity Factors

An Efficient and Accurate Numerical Method of Stress Intensity Factors Calculation of a Branched Crack

2005 ◽  
Vol 72 (3) ◽  
pp. 330-340 ◽  
Author(s):  
Xiangqiao Yan
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Crack Extension ◽  
Crack Tip ◽  
Numerical Approach ◽  
Displacement Discontinuity ◽  
Displacement Discontinuity Method ◽  
Intensity Factors ◽  
Constant Displacement ◽  
The Right

Based on the analytical solution of Crouch to the problem of a constant discontinuity in displacement over a finite line segment in an infinite elastic solid, in the present paper, the crack-tip displacement discontinuity elements, which can be classified as the left and the right crack-tip elements, are presented to model the singularity of stress near a crack tip. Furthermore, the crack-tip elements together with the constant displacement discontinuity elements presented by Crouch and Starfied are used to develop a numerical approach for calculating the stress intensity factors (SIFs) of general plane cracks. In the boundary element implementation, the left or the right crack-tip element is placed locally at the corresponding left or right crack tip on top of the constant displacement discontinuity elements that cover the entire crack surface and the other boundaries. The method is called the hybrid displacement discontinuity method (HDDM). Numerical examples are given and compared with the available solutions. It can be found that the numerical approach is simple, yet very accurate for calculating the SIFs of branched cracks. As a new example, cracks emanating from a rhombus hole in an infinite plate under biaxial loads are taken into consideration. The numerical results indicate the efficiency of the present numerical approach and can reveal the effect of the biaxial load on the SIFs. In addition, the hybrid displacement discontinuity method together with the maximum circumferential stress criterion (Erdogan and Sih) becomes a very effective numerical approach for simulating the fatigue crack propagation process in plane elastic bodies under mixed-mode conditions. In the numerical simulation, for each increment of crack extension, remeshing of existing boundaries is not required because of an intrinsic feature of the HDDM. Crack propagation is simulated by adding new boundary elements on the incremental crack extension to the previous crack boundaries. At the same time, the element characters of some related elements are adjusted according to the manner in which the boundary element method is implemented.

An Empirical Formula for Stress Intensity Factors of Double Edge Half-Circular-Hole Cracks in a Rectangular Sheet in Tension

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Xiangqiao Yan
Keyword(s):  
Stress Intensity ◽  
Boundary Element Method ◽  
Circular Hole ◽  
Stress Intensity Factors ◽  
Empirical Formula ◽  
Crack Problem ◽  
Displacement Discontinuity ◽  
Displacement Discontinuity Method ◽  
Intensity Factors ◽  
Double Edge

This note deals with the stress intensity factors (SIFs) for double edge half-circular-hole cracks in a rectangular sheet in tension by means of the displacement discontinuity method with crack-tip elements (a boundary element method) proposed recently by the author. Moreover, an empirical formula of the SIFs of the crack problem is presented and examined. It is found that the empirical formula is simple, yet accurate for evaluating the SIFs of the crack problem.

Effects of thermal and electric boundary conditions on fracture of three-dimensional thermopiezoelectric media

2017 ◽  
Vol 29 (6) ◽  
pp. 1255-1271 ◽  
Author(s):  
MingHao Zhao ◽  
Yuan Li ◽  
CuiYing Fan
Keyword(s):  
Stress Intensity ◽  
Boundary Conditions ◽  
Stress Intensity Factors ◽  
Boundary Integral Equations ◽  
Three Dimensional ◽  
Transversely Isotropic ◽  
Boundary Integral ◽  
Displacement Discontinuity ◽  
Green Functions ◽  
Intensity Factors

An arbitrarily shaped planar crack under different thermal and electric boundary conditions on the crack surfaces is studied in three-dimensional transversely isotropic thermopiezoelectric media subjected to thermal–mechanical–electric coupling fields. Using Hankel transformations, Green functions are derived for unit point extended displacement discontinuities in three-dimensional transversely isotropic thermopiezoelectric media, where the extended displacement discontinuities include the conventional displacement discontinuities, electric potential discontinuity, as well as the temperature discontinuity. On the basis of these Green functions, the extended displacement discontinuity boundary integral equations for arbitrarily shaped planar cracks in the isotropic plane of three-dimensional transversely isotropic thermopiezoelectric media are established under different thermal and electric boundary conditions on the crack surfaces, namely, the thermally and electrically impermeable, permeable, and semi-permeable boundary conditions. The singularities of near-crack border fields are analyzed and the extended stress intensity factors are expressed in terms of the extended displacement discontinuities. The effect of different thermal and electric boundary conditions on the extended stress intensity factors is studied via the extended displacement discontinuity boundary element method. Subsequent numerical results of elliptical cracks subjected to combined thermal–mechanical–electric loadings are obtained.

scholarly journals Stress and Displacement Intensity Factors of Cracks in Anisotropic Media

2020 ◽  
Vol 25 (3) ◽  
pp. 212-218
Author(s):  
S. Kuznetsov ◽  
A. Karakozova
Keyword(s):  
Stress Intensity ◽  
Anisotropic Medium ◽  
Stress Intensity Factors ◽  
Crack Front ◽  
Displacement Discontinuity ◽  
Pseudodifferential Equation ◽  
Intensity Factors ◽  
Elastic Anisotropic Medium ◽  
Arbitrary Anisotropy ◽  
Vector Valued

AbstractA relation connecting stress intensity factors (SIF) with displacement intensity factors (DIF) at the crack front is derived by solving a pseudodifferential equation connecting stress and displacement discontinuity fields for a plane crack in an elastic anisotropic medium with arbitrary anisotropy. It is found that at a particular point on the crack front, the vector valued SIF is uniquely determined by the corresponding DIF evaluated at the same point.

DETERMINATION OF RESIDUAL STRESSES AND STRESS INTENSITY FACTORS BY REMOVING LOCAL MATERIAL

2017 ◽  
Vol 48 (4) ◽  
pp. 377-398
Author(s):  
Svyatoslav Igorevich Eleonskii ◽  
Igor Nikolaevich Odintsev ◽  
Vladimir Sergeevich Pisarev ◽  
Stanislav Mikhailovich Usov
Keyword(s):  
Stress Intensity ◽  
Residual Stresses ◽  
Stress Intensity Factors ◽  
Intensity Factors ◽  
Local Material
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