J-integral evaluation for cases involving non-proportional stressing

Lei, Yuebao

doi:10.1016/j.engfracmech.2004.04.003

Cited by 59 publications

(45 citation statements)

References 9 publications

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“…7 (c-d) demonstrates that simply verifying the domain-independence of the J-integral is not sufficient in demonstrating its validity. Work has previously been carried out to modify the J-integral so that it is path-independent under complex load conditions including residual stress [13][14][15]. There is one such formulation available in Abaqus v6.14 which accounts for residual stress [5].…”

Section: Resultsmentioning

confidence: 99%

Applying Fracture Mechanics to Cracked Components Subjected to Unloading

Oliver

Pavier

Mostafavi

2016

Volume 5: High-Pressure Technology; Rudy Scavuzzo Student Paper Symposium and 24th Annual Student Paper Competition; ASME Nonde

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The J-integral is widely used as a fracture parameter for elastic-plastic materials. The J-integral describes the intensity of the stress field close to the crack tip in a power-law hardening material under a set of well-known restrictions. This study investigates what happens when one of these restrictions is broken, namely the requirement for no unloading to occur. In this work, a centre-cracked plate is subjected to a single cycle of load in which unloading occurs. A remote tensile stress is applied, then released, then applied again up to and beyond its initial magnitude. The J-integral at each step of the analysis is calculated using finite element analysis. Its validity as a fracture parameter at each step is discussed with the aid of results from a strip yield analysis of the same problem. The relevance of the results in the context of structural integrity assessment is discussed.

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Section: Resultsmentioning

confidence: 99%

Applying Fracture Mechanics to Cracked Components Subjected to Unloading

Oliver

Pavier

Mostafavi

2016

Volume 5: High-Pressure Technology; Rudy Scavuzzo Student Paper Symposium and 24th Annual Student Paper Competition; ASME Nonde

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“…When non-mechanical strains such as thermal or initial strain exist in a component, the J-Integral in the form of Eq. (8) is path dependent and cannot be used as a fracture parameter (Lei 2005;Lei et al 2000). The effects of non-mechanical strains can be considered by some modifications in J contour integral formula.…”

Section: Introductionmentioning

confidence: 98%

“…The effects of non-mechanical strains can be considered by some modifications in J contour integral formula. Modified J-Integral was expressed in the following equation (Lei 2005; Seifi and Bahrami 2010):…”

Section: Introductionmentioning

confidence: 99%

J-integral and CMOD for external inclined cracks on autofrettaged cylinders

2011

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Autofrettage is a well-known method to increase the load carrying capacity of the pressure vessels. The autofrettage outcomes can be contrary when the imperfections or material discontinuities are on the outer surface. In this study, the influences of the external inclined cracks on the fracture parameters in autofrettaged cylinders were studied. The inclination angles of cracks are different but they have the same depth. Crack mouth opening displacements and J-Integral values along the cracks front were investigated. The effects of autofrettage ratio, inclination angle, crack depth and length, the ratio of inner to outer radius and applied pressure were studied. The J-Integral values were calculated by using a modified equation taken from the recent literature, which includes the residual stress effects.

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“…Values of the J -integral for the crack under incremental loading conditions were calculated from the stress and strain fields for each condition using the domain integral method [22]. For the indented specimens, it was necessary to use the modified form of the J -integral proposed by Lei [8,23] to account for the effect of residual stress loading.…”

Section: Conventional Modellingmentioning

confidence: 99%

“…As is the case in the absence of thermal/residual stresses, the J -integral is only equal to the strain energy release rate for ideal non-linear elastic materials; its application to real elastic-plastic materials via models based on incremental plasticity is approximate. Lei proposed a similar expression for J in the presence of residual stress [8], closely following a derivation due to Wilson and Yu for the case of thermal stress [9]:…”

Section: Introductionmentioning

confidence: 99%

A Combined Experimental and Modelling Approach to Elastic–Plastic Crack Driving Force Calculation in the Presence of Residual Stresses

et al. 2016

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Since all residual stress measurement methods have inherent limitations, it is normally impractical to completely characterise a three-dimensional residual stress field by experimental means. This lack of complete information makes it difficult to incorporate measured residual stress data into the analysis of elastic-plastic fracture without resorting to simplified methods such as the Failure Assessment Diagram (FAD) approach. We propose a technique in which the complete residual stress field is reconstructed from measurements and used in finite element analysis of the fracture process. Residual elastic strains and stresses in three-point bend fracture specimens were measured using neutron diffraction and an iterative method was used to generate a self-consistent estimate of the complete residual stress field. This enabled calculation of the J contour integral for a specimen acted on by both residual stress and an externally-applied load, allowing the interaction between residual and applied stress to be observed in detail.

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J-integral evaluation for cases involving non-proportional stressing

Cited by 59 publications

References 9 publications

Applying Fracture Mechanics to Cracked Components Subjected to Unloading

Applying Fracture Mechanics to Cracked Components Subjected to Unloading

J-integral and CMOD for external inclined cracks on autofrettaged cylinders

A Combined Experimental and Modelling Approach to Elastic–Plastic Crack Driving Force Calculation in the Presence of Residual Stresses

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