Main Help → All Commands → Explicit Cracks → JContour
The JContour
command
JContour (size),<(terms)>,<(usegrid)>
where
(size)
is the size of the contour integral around the crack tip in number of elements in each direction. The default is 2. See OSUPDocs wiki for a picture of the JContour.(terms)
is 1 or 2 to specify if the J Integral should be a simple contour (1) or include an area integral inside the contour (2). The area integral corrects for dynamic effects and for axisymmetric stress states making the calculation path independent even in dynamic problems, but is slower. A contour alone (1) might be enough if the size of the contour is small, but 2 terms might be essential as the problem becomes more dynamic or as the size of the contour grows. The default is 1, but for axisymmetric calculations, the area integral is needed even for static problems, and therefore the default changes to 2 terms.
(usegrid)
is "yes" or "no" to specify that kinetic energy and work energy (used in J integration) are to be found by extrapolating velocity, stress, and strain from the grid and calculating energies from these terms (if "yes") or by directing extrapolating energies from the grid (if "no"). The default is "no". Normally you should use "no" (the default), but if vibrations in dynamic problems appear to have kinetic energy artifacts near crack tips, the "yes" mode might improve the results. Note that "yes" is also only appropriate when using small-strain, linear elastic materials (or other material in the the small strain linear elastic limit).
JContour
command is only allowed for MPM analyses.