Determination of residual stress distributions from measured stress intensity factors

1996 ◽  
Vol 74 (2) ◽  
pp. R23-R30 ◽  
Author(s):  
H. J. Schindler
Author(s):  
Adam Toft ◽  
David Beardsmore ◽  
Peter James ◽  
John Sharples ◽  
Michael Martin

In order to obtain good estimates of stress intensity factors in a structural integrity assessment, the accuracy with which a residual stress distribution is represented should be commensurate with the importance of localised peaks in residual stress, in particular where such peaks lie within the region under assessment. This paper describes work undertaken to investigate the importance of accurately representing residual stress distributions in structural integrity assessments. This has been carried out by comparing regular polynomial representations of residual stress distributions, combined with available weight function stress intensity factor solutions (as provided in the R6 procedures) with alternative polynomial representations of residual stress distributions, which provide a more accurate fit in the region of the crack. Such improvements in representation of residual stress profiles provide an indication as to how stress intensity factor solutions could, in future, be modified in order to result in improved accuracy of calculated stress intensity factors. Representation by partitioning residual stress profiles into membrane, bending and self-balancing components, in terms of providing a more straight-forward route for curve-fitting of residual stress profiles is considered. The investigation considers several transverse, through-thickness residual stress distributions. Stress intensity factors are calculated for a variety of crack sizes. Representation of the residual stress profiles in the stress intensity factor solutions are compared, as are the results of the stress intensity factor calculations. The conclusions arising provide guidance as to how current methods of curve fitting a residual stress distribution may be improved in cases where current methods may not be accurate. Advice is also provided as to the relative merits of representing residual stress distributions as a set of partitioned components or as a single distribution.


Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1331 ◽  
Author(s):  
Zhichao Han ◽  
Caifu Qian ◽  
Lanqing Tang ◽  
Huifang Li

In this paper, the interactions between two parallel cracks are investigated experimentally and numerically. Finite element models have been established to obtain the stress intensity factors and stress distributions of the parallel cracks with different positions and sizes. Fatigue crack growth tests of 304 stainless steel specimens with the single crack and two parallel cracks have been conducted to confirm the numerical results. The numerical analysis results indicate that the interactions between the two parallel cracks have an enhancement or shielding effect on the stress intensity factors, depending on the relative positions of the cracks. The criterion diagram to determine the enhancement or shielding effect between two parallel cracks is obtained. The changes of the stress fields around the cracks have been studied to explain the mechanism of crack interactions.


2004 ◽  
Vol 126 (4) ◽  
pp. 432-437 ◽  
Author(s):  
Noel P. O’Dowd ◽  
Kamran M. Nikbin ◽  
Hyeong Y. Lee ◽  
Robert C. Wimpory ◽  
Farid R. Biglari

Residual stress distributions in ferritic steel T-plate weldments have been obtained using the neutron diffraction method. It is shown that the transverse residual stress distribution for two plates of different yield strength are of similar shape and magnitude when normalized appropriately and peak stresses are on the order of the material yield strength. The resultant linear elastic stress intensity factors for these stress distributions have been obtained using the finite element method. It has been shown that the use of the recommended residual stress distributions in UK structural integrity procedures leads to a conservative assessment. The stress intensity factors for the welded T-plate have been shown to be very similar to those obtained using a smooth edge cracked plate subjected to the same local stress field.


Author(s):  
Noel P. O’Dowd ◽  
Kamran M. Nikbin ◽  
Hyeong Y. Lee ◽  
Robert C. Wimpory ◽  
Farid R. Biglari

Residual stress distributions in ferritic steel T-plate weldments have been obtained using the neutron diffraction method. It is shown that the transverse residual stress distribution for two plates of different yield strength are of similar shape and magnitude when normalised appropriately and peak stresses are on the order of the material yield strength. The resultant linear elastic stress intensity factors for these stress distributions have been obtained using the finite element method. It has been shown that the use of the recommended residual stress distributions in UK structural integrity procedures leads to a conservative assessment. The stress intensity factors for the welded T-plate have been shown to be very similar to those obtained using a smooth edge cracked plate subjected to the same local stress field.


2017 ◽  
Vol 48 (4) ◽  
pp. 377-398
Author(s):  
Svyatoslav Igorevich Eleonskii ◽  
Igor Nikolaevich Odintsev ◽  
Vladimir Sergeevich Pisarev ◽  
Stanislav Mikhailovich Usov

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