Stress Intensity Factors Caused by Residual Stress Fields in Autofrettaged Tubing

2009 ◽  
pp. 37-37-17 ◽  
Author(s):  
A Stacey ◽  
GA Webster
Keyword(s):  
Residual Stress ◽  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Stress Fields ◽  
Intensity Factors

The evaluation of stress intensity factors for plane cracks in residual stress fields

1993 ◽  
Vol 28 (3) ◽  
pp. 145-152 ◽  
Author(s):  
M D B Wilks ◽  
D Nowell ◽  
D A Hills
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Intensity ◽  
Residual Stresses ◽  
Crack Closure ◽  
Efficient Method ◽  
Stress Intensity Factors ◽  
Stress Fields ◽  
Intensity Factors ◽  
Distributed Dislocations

A reliable, efficient method is described for modelling plane cracks in arbitary residual stress fields, using the technique of distributed dislocations. This allows correctly for re-distribution of residual stresses as the crack grows. Problems where crack closure occur are discussed, and implications for solution by finite element procedures are inferred and confirmed by comparison.

Determination of Stress Intensity Factors for Gradient Stress Fields

1977 ◽  
Vol 99 (3) ◽  
pp. 477-484 ◽  
Author(s):  
J. M. Bloom ◽  
W. A. Van Der Sluys
Keyword(s):  
Stress Intensity ◽  
Crack Length ◽  
Stress Intensity Factors ◽  
Maximum Stress ◽  
Nuclear Industry ◽  
Stress Fields ◽  
Polynomial Method ◽  
Intensity Factors ◽  
Asme Code ◽  
Linear Envelope

This paper evaluates eight different analytical procedures used in determining elastic stress intensity factors for gradient or nonlinear stress fields. From a fracture viewpoint, the main interest in this problem comes from the nuclear industry where the safety of the nuclear system is of concern. A fracture mechanics analysis is then required to demonstrate the vessel integrity under these postulated accident conditions. The geometry chosen for his study is that of a 10-in. thick flawed plate with nonuniform stress distribution through the thickness. Two loading conditions are evaluated, both nonlinear and both defined by polynomials. The assumed cracks are infinitely long surface defects. Eight methods are used to find the stress intensity factor: 1–maximum stress, 2–linear envelope, 3–linearization over the crack length from ASME Code, Section XI, 4–equivalent linear moment from ASME Code, Section III, Appendix G for thermal loadings, 5–integration method from WRC 175, Appendix 4 for thermal loadings, 6–8-node singularity (quarter-point) isoparametric element in conjunction with the displacement method, 7–polynomial method, and 8–semi-infinite edge crack linear distribution over crack. Comparisons are made between all eight procedures with the finding that the methods can be ranked in order of decreasing conservatism and ease of application as follows: 1–maximum stress, 2–linear envelope, 3–linearization over the crack length, 4–polynomial method, and 5–singularity element method. Good agreement is found between the last three of these methods. The remaining three methods produce nonconservative results.

Residual Stress Redistribution Caused by Notches and Cracks in a Partially Autofrettaged Tube

1981 ◽  
Vol 103 (4) ◽  
pp. 302-306 ◽  
Author(s):  
S. L. Pu ◽  
M. A. Hussain
Keyword(s):  
Residual Stress ◽  
Stress Intensity ◽  
Residual Stresses ◽  
Stress Intensity Factors ◽  
Classical Method ◽  
Thermal Simulation ◽  
Intensity Factors ◽  
Crack Face ◽  
Simple Method ◽  
Crack Configuration

A simple method is provided for the computation of the redistribution of residual stresses and the stress intensity factors due to the introduction of notches and cracks in a partially autofrettaged tube. Numerical results of several crack and notch problems are obtained by the method of thermal simulation. These results are shown to be in excellent agreement with those obtained from the classical method of superposition. The new method based on thermal simulation is easier to apply and it avoids the alternate method of superposition requiring cumbersome distributed crack face loadings for each crack configuration.

An improved boundary element formulation for calculating stress intensity factors: Application to aerospace structures

1987 ◽  
Vol 22 (4) ◽  
pp. 203-207 ◽  
Author(s):  
M H Aliabadi ◽  
D P Rooke ◽  
D J Cartwright
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Boundary Element ◽  
Stress Intensity Factors ◽  
Crack Tip ◽  
Stress Fields ◽  
Element Formulation ◽  
Intensity Factors ◽  
Singular Stress ◽  
Singular Stress Field

In order to compute stress intensity factors accurately, the standard boundary element method is modified to take explicit account of the singularity in the stresses at a crack-tip. The known expansion terms of the crack tip displacement and stress fields are subtracted to remove the numerical difficulties associated with the representation of a singular stress field at the crack-tip. Hence the accuracy of calculation is much improved, without appreciably increasing the amount of computation involved. Furthermore, the stress intensity factor is directly obtained as a part of a solution and no extrapolations are required. The improved formulation is applied to a configuration, which is representative of a part of the wing in a civil transport aeroplane. This configuration consists of a pair of circular cut-outs (supply ports) near to which smaller holes exist; these small holes are particularly susceptible to cracking.

Sign in / Sign up

Export Citation Format

Share Document