hecoules
Mechanical
- Oct 21, 2013
- 1
The way that Abaqus evaluates the J contour integral has been updated in v6.12 to account for thermal and residual stresses in the manner described by Shih et al. (1986) and later by Lei et al. (2000) - see the Abaqus theory manual section 2.16.1.
I've been trying out J-integral evaluation for various different thermal fields. Starting with the supplied benchmark example (see Abaqus Benchmarks Manual sect. 1.16.8: Single-edged notched specimen under a thermal load), I defined various smooth thermal fields based on analytical functions (node-wise using *TEMPERATURE, rather than taking the thermal field from a .odb file as in the benchmark example) and checked the path-independence of the resulting J values. So far, so good: the results were realistic and contour-independent.
However, when I define a non-smooth thermal field, for example by raising all the nodes of a single element by 100 degrees with the rest of the nodes left at zero, the J-integral becomes strongly path-dependant. This is a bit surprising, because mathematically, the form of the underlying thermal field should not affect the path-independence (modified form of the) J-integral. Presumably, by defining a non-smooth thermal field I must be violating some assumption made by the solver, although I can't find anything which would affect this mentioned in the documentation.
Has anyone else come across this problem, or have any tips on evaluating contour integrals in the presence of thermal/residual stress fields using Abaqus?
I've been trying out J-integral evaluation for various different thermal fields. Starting with the supplied benchmark example (see Abaqus Benchmarks Manual sect. 1.16.8: Single-edged notched specimen under a thermal load), I defined various smooth thermal fields based on analytical functions (node-wise using *TEMPERATURE, rather than taking the thermal field from a .odb file as in the benchmark example) and checked the path-independence of the resulting J values. So far, so good: the results were realistic and contour-independent.
However, when I define a non-smooth thermal field, for example by raising all the nodes of a single element by 100 degrees with the rest of the nodes left at zero, the J-integral becomes strongly path-dependant. This is a bit surprising, because mathematically, the form of the underlying thermal field should not affect the path-independence (modified form of the) J-integral. Presumably, by defining a non-smooth thermal field I must be violating some assumption made by the solver, although I can't find anything which would affect this mentioned in the documentation.
Has anyone else come across this problem, or have any tips on evaluating contour integrals in the presence of thermal/residual stress fields using Abaqus?