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.

Weight Functions and Stress Intensity Factors for Longitudinal Semi-Elliptical Cracks in Thick-Wall Cylinders

1995 ◽  
Vol 117 (4) ◽  
pp. 383-389 ◽  
Author(s):  
X. J. Zheng ◽  
G. Glinka
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Complex Stress ◽  
Stress Fields ◽  
Thick Wall ◽  
Weight Functions ◽  
Intensity Factors ◽  
Crack Face ◽  
Reference Stress ◽  
Elliptical Cracks

Weight functions for the surface and the deepest point of an internal longitudinal semi-elliptical crack in a thick-wall cylinder (Ri/t = 1) were derived from a general weight function and two reference stress intensity factors. For several linear and nonlinear crack face stress, fields, the weight functions were validated against finite element data. Stress intensity factors were also calculated for the Lame´ through the thickness stress distribution induced by internal pressure. The weight functions appear to be particularly suitable for fatigue and fracture analysis of surface semi-elliptical cracks in complex stress fields. All stress intensity factor expressions given in the paper are valid for cylinders with the inner-radius-to-wall-thickness ratio, Ri/t = 1.

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.

Calculation of Stress Intensity Factors and Crack Opening Displacements for Cracks Subjected to Complex Stress Fields

2003 ◽  
Vol 125 (3) ◽  
pp. 260-266 ◽  
Author(s):  
A. Kiciak ◽  
G. Glinka ◽  
D. J. Burns
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Fatigue Cracks ◽  
Crack Opening ◽  
Complex Stress ◽  
Pressure Vessels ◽  
Stress Fields ◽  
Function Technique ◽  
Weight Functions ◽  
Intensity Factors

Fatigue cracks in shot peened and case hardened notched machine components and high-pressure vessels are subjected to the stress fields induced by the external load and the residual stress resulting from the surface treatment or autofrettage. Both stress fields are usually nonuniform and available handbook stress intensity factor solutions are in most cases unavailable for such configurations, especially in the case of two-dimensional surface breaking cracks such as semi-elliptical and quarter-elliptical cracks at notches. The method presented in the paper makes it possible to calculate stress intensity factors for such cracks and complex stress fields by using the generalized weight function technique. It is also shown that the generalized weight functions make it possible to calculate the crack opening displacement field often used in the determination of the critical load or the critical crack size.

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.

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