scholarly journals Analysis of Multiple Fatigue Cracks—Part II: Results

1992 ◽  
Vol 114 (3) ◽  
pp. 462-468 ◽  
Author(s):  
M. C. Dubourg ◽  
M. Godet ◽  
B. Villechaise
Keyword(s):  
Load Transfer ◽  
Fatigue Cracks ◽  
Interfacial Crack ◽  
Frictional Resistance ◽  
Mode I ◽  
Crack Interaction ◽  
Intensity Factors ◽  
Linear Elastic ◽  
Elastic Fracture ◽  
Crack Faces

A semianalytical model of multiple fatigue crack analysis in sliding contact is developed. Linear elastic fracture mechanics is applied. Frictional resistance between crack faces is taken into account. Five crack interaction mechanisms have been identified. Load transfer between cracks can cause both significant increases and drops in stress intensity factors both in mode I and II. The interaction depends on the distance between cracks, their relative position with respect to the loading zone, and the interfacial crack coefficient of friction.

Propagation of Fatigue Cracks Emanating from Sharp Notches under Different Loading Direction

2007 ◽  
Vol 348-349 ◽  
pp. 461-464
Author(s):  
Matteo Benedetti ◽  
M. Beghini ◽  
L. Bertini ◽  
V. Fontanari
Keyword(s):  
Stress Intensity ◽  
Applied Load ◽  
Fatigue Cracks ◽  
Intensity Factors ◽  
Linear Elastic ◽  
Notched Specimens ◽  
Loading Direction ◽  
Al 7075 ◽  
Elastic Fracture ◽  
Edge Cracks

The present paper is aimed at investigating the behaviour of fatigue cracks emanating from sharp V-shaped notches. To this purpose, several tests has been conducted on Al-7075-T651 notched specimens using a servohydraulic machine by changing the directions and levels of the applied load. The crack growth have been interpreted on the basis of a linear elastic fracture mechanics approach by adopting a weight function derived by the authors for the calculation of the stress intensity factors (SIFs) of inclined edge-cracks emanating from V-shaped notches.

Boundary Element Formulations in Fracture Mechanics

1997 ◽  
Vol 50 (2) ◽  
pp. 83-96 ◽  
Author(s):  
M. H. Aliabadi
Keyword(s):  
Stress Intensity ◽  
Fracture Mechanics ◽  
Boundary Element ◽  
Growth Analysis ◽  
Review Article ◽  
Boundary Element Methods ◽  
Intensity Factors ◽  
Linear Elastic ◽  
Transient Problems ◽  
Elastic Fracture

This article reviews advances in the application of boundary element methods (BEM) to fracture mechanics which have taken place over the last 25 years. Applications discussed include linear, nonlinear and transient problems. Also reviewed are contributions using the indirect boundary element formulations. Over this period the method has emerged as the most efficient technique for the evaluation of stress intensity factors (SIF) and crack growth analysis in the context of linear elastic fracture mechanics (LEFM). Much has also been achieved in the application to dynamic fracture mechanics. This review article contains 289 references.

Numerical Study of a Plate with a Pre-Cracked Circular Notch

2014 ◽  
Vol 627 ◽  
pp. 101-104 ◽  
Author(s):  
Francesco Caputo ◽  
A. de Luca ◽  
Giuseppe Lamanna ◽  
Alessandro Soprano
Keyword(s):  
Fracture Mechanics ◽  
Plastic Zone ◽  
Numerical Study ◽  
Plastic Zone Size ◽  
Mode I ◽  
Zone Size ◽  
Linear Elastic ◽  
Elastic Fracture ◽  
Notch Edge ◽  
Circular Notch

In the recent years, the study of the behaviour of damaged structures has been focused on cracked components in presence of an extensive material yielding at the crack tip; under this condition, linear elastic fracture mechanics theory (LEFM) is not able to describe the real plastic zone shape and size. Within this work, an extensive numerical analysis, based on elastic plastic fracture mechanics theory (EPFM), of the plastic zone size at the tip of a Mode I pre-crack at the notch edge in a plate is presented.

scholarly journals Subsurface Cracks Under Conditions of Slip, Stick, and Separation Caused by a Moving Compressive Load

1987 ◽  
Vol 54 (2) ◽  
pp. 393-398 ◽  
Author(s):  
S. D. Sheppard ◽  
J. R. Barber ◽  
M. Comninou
Keyword(s):  
Integral Equation ◽  
Stress Intensity ◽  
Coulomb Friction ◽  
Compressive Load ◽  
Mode I ◽  
Subsurface Crack ◽  
Intensity Factors ◽  
Subsurface Cracks ◽  
Load Location ◽  
Crack Faces

The Mode I and II stress intensity factors (KI, KII) at the two tips of a subsurface crack subjected to a moving compressive load are studied. Coulomb friction along the crack faces results in a number of history dependent slip-stick configurations and nonsymmetric variation in KI and KII. The formulation used to study this variation involves a singular integral equation in two variables which must be solved numerically, and because of the history dependence, requires an incremental solution. Crack lengths and coefficients of friction that result in as many as three zones for any load location are considered in this paper, while a previous paper (Sheppard et al., in press) was limited to configurations involving two zones only.

scholarly journals Evaluation of the criticality of cracks in ice shelves using finite element simulations

2012 ◽  
Vol 6 (5) ◽  
pp. 973-984 ◽  
Author(s):  
C. Plate ◽  
R. Müller ◽  
A. Humbert ◽  
D. Gross
Keyword(s):  
Stress Intensity ◽  
Configurational Forces ◽  
Intensity Factors ◽  
Physical Processes ◽  
Ice Shelf ◽  
Critical Crack ◽  
Ice Shelves ◽  
Various Boundary Conditions ◽  
Linear Elastic ◽  
Elastic Fracture

Abstract. The ongoing disintegration of large ice shelf parts in Antarctica raise the need for a better understanding of the physical processes that trigger critical crack growth in ice shelves. Finite elements in combination with configurational forces facilitate the analysis of single surface fractures in ice under various boundary conditions and material parameters. The principles of linear elastic fracture mechanics are applied to show the strong influence of different depth dependent functions for the density and the Young's modulus on the stress intensity factor KI at the crack tip. Ice, for this purpose, is treated as an elastically compressible solid and the consequences of this choice in comparison to the predominant incompressible approaches are discussed. The computed stress intensity factors KI for dry and water filled cracks are compared to critical values KIc from measurements that can be found in literature.

The Growth Rate of Semi-Elliptic Fatigue Cracks in Thick-Walled Cylinders

1983 ◽  
Vol 22 ◽  
Author(s):  
W. A. Lees ◽  
P. S. J. Crofton
Keyword(s):  
Growth Rate ◽  
Crack Growth Rate ◽  
Internal Pressure ◽  
Crack Growth ◽  
Fatigue Cracks ◽  
Low Alloy Steel ◽  
Linear Elastic ◽  
Fatigue Data ◽  
Elastic Fracture ◽  
Crack Growth Rates

ABSTRACTThe rate of growth of fatigue cracks originating at the bore and at the outside surface of thick-walled low alloy steel cylinders has been measured for cylinders subjected to fluctuating internal pressure.Analysis of the results using linear elastic fracture mechanics relationships shows that crack growth rates found in air adequately predict the behaviour of cracks growing from the outside surface of a cylinder.Fatigue cracks growing from the bore of a cylinder subjected to fluctuating internal pressure are found to advance at a consistently higher rate than that predicted from crack growth rate tests carried out in air.These findings are discussed in relation to the proposed adoption of existent strain-life fatigue data for pressure vessel design.

Application of Fracture Mechanics to Arch Dam Analysis

2004 ◽  
Vol 261-263 ◽  
pp. 57-62 ◽  
Author(s):  
Shui Cheng Yang ◽  
Li Song ◽  
Hong Jian Liao
Keyword(s):  
Fracture Mechanics ◽  
Three Dimensional ◽  
Arch Dam ◽  
Mixed Mode Fracture ◽  
Analysis Method ◽  
Intensity Factors ◽  
Arch Dams ◽  
Linear Elastic ◽  
Elastic Fracture ◽  
The Stability

The authors present a procedure for the analysis of the stability and propagation of cracks in arch dams based on linear elastic fracture mechanics. A finite element method was used to calculate the stress intensity factors(KⅠ, KⅡ and KⅢ) of crack in the concrete arch dam, and fracture analysis for arch dams was carried out, which based on the criterion of three-dimensional mixed mode fracture of concrete from the experiment. The analysis method can be applied to evaluate the safety of the arch dam and improve the design for arch dam.

scholarly journals Combined Visibility and Surrounding Triangles Method for Simulation of Crack Discontinuities in Meshless Methods

2012 ◽  
Vol 2012 ◽  
pp. 1-16 ◽  
Author(s):  
H. Pirali ◽  
F. Djavanroodi ◽  
M. Haghpanahi
Keyword(s):  
Diffraction Method ◽  
Meshless Methods ◽  
Standard Test ◽  
The Finite Element Method ◽  
Linear Elastic ◽  
Element Free Galerkin ◽  
Elastic Fracture ◽  
Element Free ◽  
Crack Faces ◽  
Good Agreement

In this paper a combined node searching algorithm for simulation of crack discontinuities in meshless methods called combined visibility and surrounding triangles (CVT) is proposed. The element free Galerkin (EFG) method is employed for stress analysis of cracked bodies. The proposed node searching algorithm is based on the combination of surrounding triangles and visibility methods; the surrounding triangles method is used for support domains of nodes and quadrature points generated at the vicinity of crack faces and the visibility method is used for points located on the crack faces. In comparison with the conventional methods, such as the visibility, the transparency, and the diffraction method, this method is simpler with reasonable efficiency. To show the performance of this method, linear elastic fracture mechanics analyses are performed on number of standard test specimens and stress intensity factors are calculated. It is shown that the results are in good agreement with the exact solution and with those generated by the finite element method (FEM).

Examination of Ellipticity and Stress Intensity Factors by Photoelastic and Caustic Methods

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1898-1903
Author(s):  
Tsutomu Ezumi ◽  
Katsunao Suzuki
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Stress Intensity Factors ◽  
Experimental Methods ◽  
Intensity Factors ◽  
Linear Elastic ◽  
Freezing Method ◽  
Elastic Fracture ◽  
Caustics Method

In the field of linear elastic fracture mechanics, the stress intensity factor approach has been widely accepted as a valid means for predicting the behavior of a material in the presence of a crack or flaw. To optimize their dimension and to ensure their safety in service, a practical study of the strength under centrifugal force is important. In this paper, it is investigated that the stress intensity factors K_ and K_ on the rotating elliptic disks having outside cracks by means of combining the photoelastic freezing method and the caustics method. Stress intensity factors K and K were determined by using two experimental methods, as a function of ellipticity of the elliptic disk and at two different velocities. The results of these experimental methods was nearly agreement, and attracted the interest.

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