Fracture Analysis of a Semi-Elliptical Surface Crack in Hollow Cylinders

2015 ◽  
Vol 764-765 ◽  
pp. 1175-1179
Author(s):  
Shiuh Chuan Her ◽  
Hao Hsi Chang
Keyword(s):  
Stress Intensity ◽  
Weight Function ◽  
Stress Intensity Factors ◽  
Surface Crack ◽  
Surface Cracks ◽  
Stress Distributions ◽  
Intensity Factors ◽  
Wide Range ◽  
Hollow Cylinders ◽  
Good Agreement

In this investigation, the weight function method was employed to calculate the stress intensity factors for semi-elliptical surface crack in a hollow cylinder. An uniform stress and a linear stress distributions were used as the two references to determine the weight function. The weight function was then applied to a wide range of semi-elliptical surface cracks subjected to non-linear loadings. The stress intensity factors obtained by the weight function were compared with literature results. Good agreement demonstrates the accuracy of the present approach.

Weight Functions for an External Longitudinal Semi-Elliptical Surface Crack in a Thick-Walled Cylinder

1997 ◽  
Vol 119 (1) ◽  
pp. 74-82 ◽  
Author(s):  
A. Kiciak ◽  
G. Glinka ◽  
D. J. Burns
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Surface Crack ◽  
Complex Stress ◽  
Weight Functions ◽  
Stress Distributions ◽  
Intensity Factors ◽  
Reference Stress ◽  
Pressurized Cylinder ◽  
Walled Cylinder

Mode I weight functions were derived for the deepest and surface points of an external radial-longitudinal semi-elliptical surface crack in a thick-walled cylinder with the ratio of the internal radius to wall thickness, Ri/t = 1.0. Coefficients of a general weight function were found using the method of two reference stress intensity factors for two independent stress distributions, and from properties of weight functions. Stress intensity factors calculated using the weight functions were compared to the finite element data for several different stress distributions and to the boundary element method results for the Lame´ hoop stress in an internally pressurized cylinder. A comparison to the ASME Pressure Vessel Code method for deriving stress intensity factors was also made. The derived weight functions enable simple calculations of stress intensity factors for complex stress distributions.

STRESS INTENSITY FACTORS OF A SEMI-ELLIPTICAL CRACK IN A HOLLOW CYLINDER

2015 ◽  
Vol 39 (3) ◽  
pp. 557-568
Author(s):  
Shiuh-Chuan Her ◽  
Hao-Hi Chang
Keyword(s):  
Finite Element ◽  
Stress Intensity ◽  
Hollow Cylinder ◽  
Stress Intensity Factors ◽  
Surface Crack ◽  
Crack Depth ◽  
Weight Functions ◽  
Intensity Factors ◽  
Regular Elements ◽  
Wide Range

In this investigation, the weight function method was employed to calculate stress intensity factors for semi-elliptical surface crack in a hollow cylinder. A uniform stress and a linear stress distribution were used as the two references to determine the weight functions. These two factors were obtained by a three-dimensional finite element method which employed singular elements along the crack front and regular elements elsewhere. The weight functions were then applied to a wide range of semi-elliptical surface crack subjected to non-linear loadings. The results were validated against finite element data and compared with other analyses. In the parametric study, the effects of the ratio of the surface crack depth to length ranged from 0.2 to 1.0 and the ratio of the crack depth to the wall thickness ranged from 0.2 to 0.8 on stress intensity factors were investigated.

scholarly journals Stress Analysis and Stress-Intensity Factors for Finite Geometry Solids Containing Rectangular Surface Cracks

1977 ◽  
Vol 44 (3) ◽  
pp. 442-448 ◽  
Author(s):  
J. P. Gyekenyesi ◽  
A. Mendelson
Keyword(s):  
Stress Intensity ◽  
Displacement Field ◽  
Stress Intensity Factors ◽  
Surface Crack ◽  
Crack Opening ◽  
Crack Depth ◽  
Elastic Equilibrium ◽  
Finite Geometry ◽  
Surface Cracks ◽  
Intensity Factors

The line method of analysis is applied to the Navier-Cauchy equations of elastic equilibrium to calculate the displacement field in a finite geometry bar containing a variable depth rectangular surface crack under extensionally applied uniform loading. The application of this method to these equations leads to coupled sets of simultaneous ordinary differential equations whose solutions are obtained along sets of lines in a discretized region. Using the obtained displacement field, normal stresses, and the stress-intensity factor variation along the crack periphery are calculated for different crack depth to bar thickness ratios. Crack opening displacements and stress-intensity factors are also obtained for a through-thickness, center-cracked bar with variable thickness. The reported results show a considerable potential for using this method in calculating stress-intensity factors for commonly encountered surface crack geometries in finite solids.

scholarly journals Stress-Intensity Factors for Internal Surface Cracks in Cylindrical Pressure Vessels

1980 ◽  
Vol 102 (4) ◽  
pp. 342-346 ◽  
Author(s):  
J. C. Newman ◽  
I. S. Raju
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Intensity ◽  
Wall Thickness ◽  
Stress Intensity Factors ◽  
Crack Depth ◽  
Internal Surface ◽  
Surface Cracks ◽  
Intensity Factors ◽  
Wide Range

The purpose of this paper is to present stress-intensity factors for a wide range of semi-elliptical surface cracks on the inside of pressurized cylinders. The ratio of crack depth to crack length ranged from 0.2 to 1; the ratio of crack depth to wall thickness ranged from 0.2 to 0.8; and the ratio of wall thickness to vessel radius was 0.1 to 0.25. The stress-intensity factors were calculated by a three-dimensional finite-element method. The finite-element models employ singularity elements along the crack front and linear-strain elements elsewhere. The models had about 6500 degrees of freedom. The stress-intensity factors were evaluated from a nodal-force method. An equation for the stress-intensity factors was obtained from the results of the present analysis. The equation applies over a wide range of configuration parameters and was within about 5 percent of the present results. A comparison was also made between the present results and other analyses of internal surface cracks in cylinders. The results from a boundary-integral equation method were in good agreement (± 2 percent) and those from another finite-element method were in fair agreement (± 8 percent) with the present results.

scholarly journals Weight Functions and Stress Intensity Factors for Axial Cracks in Hollow Cylinders

1994 ◽  
Vol 116 (4) ◽  
pp. 423-430 ◽  
Author(s):  
C.-C. Ma ◽  
J.-I. Huang ◽  
C.-H. Tsai
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Weight Function ◽  
Stress Intensity Factors ◽  
Function Method ◽  
Weight Functions ◽  
Intensity Factors ◽  
Arbitrary Loading ◽  
Hollow Cylinders

In this study, stress intensity factors for axial cracks in hollow cylinders subjected to mechanical and thermal loadings are determined by using the weight function method. The weight function is a universal function for a given cracked body and can be obtained from any arbitrary loading system. The weight function may be thought of as Green’s function for the stress intensity factor of cracked bodies. Once the weight function for a cracked body is determined, the stress intensity factor for any arbitrary loading can be simply and efficiently evaluated through the integration of the product of the loading and weight function. A numerical method for the determination of weight functions relevant to cracked bodies with finite dimensions is used. Results for weight functions covering a wide range of hollow cylinder geometries are presented in functional or graphical form. The explicit crack face weight functions for applying mechanical loadings are obtained by using the least-squares fitting procedure. As a demonstration, some examples of special loading problems are solved by the weight function method, and the results are compared with available results in the published literature.

Stress intensity factors for semi-elliptical surface cracks in semicircularly notched tension plates

1997 ◽  
Vol 32 (3) ◽  
pp. 229-236 ◽  
Author(s):  
X B Lin ◽  
R A Smith
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Crack Depth ◽  
Finite Thickness ◽  
J Integral ◽  
Surface Cracks ◽  
Intensity Factors ◽  
Wide Range ◽  
Half Length ◽  
Half Thickness

Stress intensity factors for semi-elliptical surface cracks located at the centre of a semicircular edge notch in a finite thickness plate subjected to a remote tensile load are presented in a tabulated format. A wide range of geometry ratios are considered. They are all combinations of the following ratios: the ratio of crack surface half-length to plate half-thickness, c/t = 0.2, 0.4, 0.6, 0.8 and 0.95; the ratio of crack depth to surface half-length, a/c = 0.2, 0.4, 0.6, 0.8 and 1; and the ratio of notch radius to plate half-thickness, r/t = 0.5, 1, 2 and 3. Both the quarter-point displacement and J.-integral methods based on three-dimensional finite element analyses were employed for the calculation of stress intensity factors. The calculation accuracy was studied by analysing the J.-integral path independence and comparing stress intensity factor results with other solutions available in the literature.

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