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J integral

Which theory Abaqus' Contour Integral for the determination of SIFs is based on?

I am actually using Abaqus' Contour Integral for the determination of stress intensity factors. But I do not know, which theory it is based on. Is it the same like the path-independent determination of J integral? Or is there a difference?

Bent F. Sørensen's picture

A paper on fracture resistance enhancement of layered structures by multiple cracks

We have just published a new paper that presents a theoretical model to test if the fracture resistance of a layered structure can be increased by introducing weak layers changing the cracking mechanism. An analytical model, based on the J integral, predicts a linear dependency between the number of cracks and the steady state fracture resistance. A finite element cohesive zone model, containing two cracking planes for simplicity, is used to check the theoretical model and its predictions.

J integral variation through thickness in tubes with through-wall circumferential crack, calculated with Abaqus/CAE

Dear friends: I am a PhD candidate studying fracture problems in tubes. I am doing J integral calculations in Abaqus, for tubes with through-wall circumferential cracks subjected to tensile and bending loads. I am using quadratic 20 nodes isoparametric elements with reduced integration (C3D20R), ranging from two to five elements through the wall thickness mesh.

use of CINT command for J integral calculation of 3d model with ansys

I used for the first time the CINT command with ansys, and I get strange results:

negative values

very different values for 2 adjacent nodes on the crack front

non converging values (values fluctuating from 1 contour to another, going up and down)

Also, i don't know what are the units of the J integral (I am using SI units, dimensions in mm ).  It's important to know so I can calculate the SIF

How can I know what contour gives the best result? what are the units of the Jintegral in the SI.

Anybody have some information for me?

ESIS's picture

Discussion of fracture paper #1 - A contol volume model

This is a premiere: my first contribution to the new ESIS' blog announced in January. Why comment on papers in a scientific journal after they have passed the review process already? Not to question their quality, of course, but animating a vital virtue of science again, namely discussion. The pressure to publish has increased so much that one may doubt whether there is enough time left to read scientific papers. This impression is substantiated by my experience as a referee.

ravimech04333's picture

Fracture Mechanics


Can any one help me in how to solve J INTEGRAL for simple 2D geometries.Atleast can anyone help me where can i get PDF files on J integral... Plz its urgent its a part of Thesis...   Plz post your conmments at

David J Unger's picture

J-Integral Elliptical Hole (Plane Stress) Perfectly Plastic Material

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The fracture mechanics community may be interested in a new evaluation of a J-Integral for a fundamental geometry:  an elliptical hole in a perfectly plastic material under the Tresca yield condition for plane stress loading conditions. The analysis is exact and involves only elementary functions.  This makes the problem suitable as a classroom example or as a homework problem for a graduate level course in fracture mechanics.  See J. Elasticity (2008) 92:217-226.

Jintegral and Umat subroutine

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cracking analyses in a bended sandwich beam

I'm studying cracking analyses in a three point loaded specimen of a composed beam.I'm using ANSYS and i want to create codes for estimation of J integral and energy release rate in the vicinity of crack tip.After that i'll calculate the stresses and strains fields,and then i can compare the equivalent fields i retrived using CTOD  and K(I,II,III) factors (according to ANSYS algorithm).

My problem is that I'd like to find a relationship between the above mentioned quantities(J,G)  with K(I,II,III)factors.

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