The dynamics stress intensity factor of a moving internal crack subjected to incident shear waves

2002 ◽  
Author(s):  
I-Chung Weng ◽  
R.Y. Chen
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Shear Waves ◽  
Internal Crack

Interaction Between Interfacial Cavity/Crack and Internal Crack—Part II: Simulation

2003 ◽  
Vol 72 (3) ◽  
pp. 394-399 ◽  
Author(s):  
P. B. N. Prasad ◽  
Norio Hasebe ◽  
X. F. Wang
Keyword(s):  
Stress Intensity Factor ◽  
Integral Equation ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Singular Integral Equation ◽  
Internal Crack ◽  
Uniform Loading ◽  
Distributed Dislocation ◽  
Point Dislocation ◽  
Dislocation Technique

This paper discusses the interaction of an interfacial cavity/crack with an internal crack in a bimaterial plane under uniform loading at infinity. The point dislocation solution is used to simulate internal crack by using the distributed dislocation technique. The resulting singular integral equation is solved numerically and the stress intensity factor variations are plotted for some cases of internal crack interacting with interfacial cavity/crack.

Stress Intensity Factors for a Curved-Front Internal Crack in an Autofrettaged Tube With Bauschinger Effect

2003 ◽  
Author(s):  
Choon-Lai Tan ◽  
Anthony P. Parker ◽  
Chantz W. V. Cassell
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Wall Thickness ◽  
Bauschinger Effect ◽  
Boundary Integral ◽  
Maximum Depth ◽  
Internal Crack ◽  
Plastic Behavior ◽  
Perfectly Plastic

Pressure vessel steels exhibit the Bauschinger effect that significantly reduces post-autofrettage residual compressive hoop stresses in the near-bore region in comparison with ‘ideal’ (elastic-perfectly plastic) behavior. These reduced hoop stress profiles were calculated using Von Mises’ criterion via a non-linear analysis for the case of open-end (engineering plane strain) autofrettage. These profiles were then used to obtain stress intensity factor solutions via the Boundary Integral Equation (BIE) method, commonly known as the Boundary Element Method (BEM). Results are presented for tubes of diameter ratio 2 and 2.5 with an internal semi-elliptical surface crack having a maximum depth/surface length ratio of 0.4 (i.e. an eccentricity of 0.8). Crack depths range from 20% to 80% of wall thickness and results are presented for seven locations on the crack front from maximum depth to free surface. For crack depths up to 20% of wall thickness there is a significant reduction in magnitude of autofrettage stress intensity factor due to Bauschinger effect. For typical overstrain levels this reduction is approximately 30% of ‘ideal’ values. Such a reduction may, in turn, cause an order of magnitude reduction in the fatigue lifetime of the vessel.

Stress Intensity Factors for a Curved-Front Internal Crack in an Autofrettaged Tube With Bauschinger Effect

2004 ◽  
Vol 126 (2) ◽  
pp. 229-233 ◽  
Author(s):  
Choon-Lai Tan ◽  
Anthony P. Parker ◽  
Chantz W. V. Cassell
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Wall Thickness ◽  
Bauschinger Effect ◽  
Boundary Integral ◽  
Maximum Depth ◽  
Internal Crack ◽  
Plastic Behavior ◽  
Perfectly Plastic

Pressure vessel steels exhibit the Bauschinger effect that significantly reduces post-autofrettage residual compressive hoop stresses in the near-bore region in comparison with ‘ideal’ (elastic-perfectly plastic) behavior. These reduced hoop stress profiles were calculated using Von Mises’ criterion via a nonlinear analysis for the case of open-end (engineering plane strain) autofrettage. These profiles were then used to obtain stress intensity factor solutions via the Boundary Integral Equation (BIE) method, commonly known as the Boundary Element Method (BEM). Results are presented for tubes of diameter ratio 2 and 2.5 with an internal semi-elliptical surface crack having a maximum depth/surface length ratio of 0.4 (i.e., an eccentricity of 0.8). Crack depths range from 20% to 80% of wall thickness and results are presented for seven locations on the crack front from maximum depth to free surface. For crack depths up to 20% of wall thickness there is a significant reduction in magnitude of autofrettage stress intensity factor due to Bauschinger effect. For typical overstrain levels this reduction is approximately 30% of “ideal” values. Such a reduction may, in turn, cause an order of magnitude reduction in the fatigue lifetime of the vessel.

Fracture of a Finite Medium with a Circular Internal Crack under Hyperbolic Heat Conduction-Prescribed Crack Face Temperature

2013 ◽  
Vol 716 ◽  
pp. 402-408 ◽  
Author(s):  
B. Wang
Keyword(s):  
Stress Intensity Factor ◽  
Heat Conduction ◽  
Thermal Stress ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Internal Crack ◽  
Hyperbolic Heat Conduction ◽  
Thermal Stress Intensity Factor ◽  
Transient Thermal ◽  
Fourier Model

This paper studies the fracture mechanics of a thermoelastic material layer with an internal crack subjecting to a prescribed temperature. The hyperbolic heat conduction theory is used and the transient thermal stress intensity factor is obtained. Comparisons of the results from the non-Fourier model and the Fourier model are made. The results demonstrate that the non-Fourier effect has a strong effect on the transient thermal stress around the crack tip. Thermal stress intensity factor predicted by the hyperbolic heat conduction model is considerably high then that predicted by the classical Fourier.

A Thick-Walled Cylinder With an Axisymmetric Internal or Edge Crack

1978 ◽  
Vol 45 (2) ◽  
pp. 281-286 ◽  
Author(s):  
R. Erdol ◽  
F. Erdogan
Keyword(s):  
Stress Intensity Factor ◽  
Thermal Stress ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Edge Crack ◽  
Axial Stress ◽  
Crack Depth ◽  
Internal Crack ◽  
Cauchy Kernel ◽  
Walled Cylinder

The paper considers the elastostatic axisymmetric problem for a long thick-walled cylinder containing a ring-shaped internal or edge crack. Using the standard transform technique the problem is formulated in terms of an integral equation which has a simple Cauchy kernel for the internal crack and a generalized Cauchy kernel for the edge crack as the dominant part. As examples the uniform axial load and the steady-state thermal stress problems have been solved and the related stress-intensity factors have been calculated. Among other findings the results show that in the cylinder under uniform axial stress containing an internal crack the stress-intensity factor at the inner tip is always greater than that at the outer tip for equal net ligament thicknesses and in the cylinder with an edge crack which is under a state of thermal stress the stress-intensity factor is a decreasing function of the crack depth, tending to zero as the crack depth approaches the wall thickness.

Damage accumulation near a hole under low cycle fatigue proceeding from measurements of local deformation response

2020 ◽  
Vol 86 (10) ◽  
pp. 46-55
Author(s):  
S. I. Eleonsky ◽  
Yu. G. Matvienko ◽  
V. S. Pisarev ◽  
A. V. Chernov
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Damage Accumulation ◽  
Stress Ratio ◽  
Low Cycle Fatigue ◽  
Accumulation Process ◽  
Stress Range ◽  
Cycle Fatigue ◽  
Deformation Response

A new destructive method for quantitative determination of the damage accumulation in the vicinity of a stress concentrator has been proposed and verified. Increase of damage degree in local area with a high level of the strain gradient was achieved through preliminary low-cycle pull-push loading of plane specimens with central open holes. The above procedure is performed for three programs at the same stress range (333.3 MPa) and different stress ratio values 0.33, – 0.66 and – 1.0, and vice versa for two programs at the same stress ratio – 0.33 and different stress range 333.3 and 233.3 MPa. This process offers a set of the objects to be considered with different degree of accumulated fatigue damages. The key point of the developed approach consists in the fact that plane specimens with open holes are tested under real operation conditions without a preliminary notching of the specimen initiating the fatigue crack growth. The measured parameters necessary for a quantitative description of the damage accumulation process were obtained by removing the local volume of the material in the form of a sequence of narrow notches at a constant level of external tensile stress. External load can be considered an amplifier enhancing a useful signal responsible for revealing the material damage. The notch is intended for assessing the level of fatigue damage, just as probe holes are used to release residual stress energy in the hole drilling method. Measurements of the deformation response caused by local removing of the material are carried out by electronic speckle-pattern interferometry at different stages of low-cycle fatigue. The transition from measured in-plane displacements to the values of the stress intensity factor (SIF) and the T-stress was carried out on the basis of the relations of linear fracture mechanics. It was shown that the normalized dependences of the stress intensity factor on the durability percentage for the first notch (constructed for four programs of cyclic loading with different parameters), reflect the effect of the stress ratio and stress range of the loading cycle on the rate of damage accumulation. The data were used to obtain the explicit form of the damage accumulation function that quantitatively describes damage accumulation process. The functions were constructed for different stress ratios and stress ranges.

A new type of cracks adding to Griffith–Irwin cracks

2019 ◽  
Vol 485 (2) ◽  
pp. 162-165
Author(s):  
V. A. Babeshko ◽  
O. M. Babeshko ◽  
O. V. Evdokimova
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Tip ◽  
Stress Concentrations ◽  
New Type

The distinctions in the description of the conditions of cracking of materials are revealed. For Griffith–Irwin cracks, fracture is determined by the magnitude of the stress-intensity factor at the crack tip; in the case of the new type of cracks, fracture occurs due to an increase in the stress concentrations up to singular concentrations.

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