Reference stress intensity factors with application to weight functions for internal circumferential cracks in cylinders

2001 ◽  
Vol 68 (4) ◽  
pp. 435-454 ◽  
Author(s):  
I.S Jones ◽  
G Rothwell
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Weight Functions ◽  
Intensity Factors ◽  
Reference Stress

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.

A Method for Assessing the “Local” Accuracy of Weight Functions for Plates With Embedded Cracks

1995 ◽  
Author(s):  
S. W. Ng ◽  
K. J. Lau
Keyword(s):  
Finite Element ◽  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Weight Functions ◽  
Finite Element Analyses ◽  
Intensity Factors ◽  
Local Accuracy ◽  
New Algorithms

Abstract In this paper a procedure is developed to assess the “local” accuracy of weight functions for finding stress intensity factors of centrally cracked finite plates given by Tsai and Ma (1989). It is found that the weight functions can be used to calculate stress intensity factors for practical cases, with “local” accuracy being within 6 %. In addition, weight functions generated from two finite element analyses are found to be accurate and may be used to assess new algorithms for finding weight functions.

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