# Contour integral evaluation

 Abaqus/Standard offers the evaluation of several parameters for fracture mechanics studies based on either the conventional finite element method or the extended finite element method (XFEM, see Modeling discontinuities as an enriched feature using the extended finite element method): the J-integral, which is widely accepted as a quasi-static fracture mechanics parameter for linear material response and, with limitations, for nonlinear material response; the $Ct$-integral, which has an equivalent role to the J-integral in the context of time-dependent creep behavior (Rate-dependent plasticity: creep and swelling) in a quasi-static step (Quasi-static analysis); the stress intensity factors, which are used in linear elastic fracture mechanics to measure the strength of the local crack-tip fields; the crack propagation direction—i.e., the angle at which a preexisting crack will propagate; and the T-stress, which represents a stress parallel to the crack faces and is used as an indicator of the extent to which parameters like the J-integral are useful characterizations of the deformation field around the crack. Contour integrals: are output quantities—they do not affect the results; can be requested only in general analysis steps; can be used only with two-dimensional quadrilateral elements or three-dimensional brick elements when used with the conventional finite element method; can be evaluated without requiring a detailed conforming mesh around the crack tips when used with XFEM; and are currently available only for first-order or second-order tetrahedron and first-order brick elements with isotropic elastic material when used with XFEM. The following topics are discussed:
 Related Topics About fracture mechanics In Other Guides *CONTOUR INTEGRAL Using contour integrals to model fracture mechanics

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