Figure 12.2 "Examples of Singular Elements" in the ANSYS 10.0 Structural Analysis
Guide does not appear to be correct. The degenerate shape for the PLANE82 element
shows nodes I, L, and P to be coincident. Is this allowed?


In short, no, but the Fracture Mechanics documentation is going to be completely
rewritten in ANSYS 11.0, so this error will be corrected then. Per the Elements
Reference, the PLANE82 coincident nodes must be K, L, and O (not I, L, and P).
Further, the figure implies that node "I" must be at the crack tip, but that is not
true. Please note that the KSCON command correctly creates the required 2D mesh.

Also, the documentation in Section 12.2.1.2 "3-D Fracture Models" incorrectly states
that "... you need to make sure that the crack front is along edge KO of the elements."
As with the 2D case, the only requirements are:

1) Element nodal connectivity must match that documented in the Elements Reference

2) Skewed mid-side nodes must be moved closer to the singularity point, as is shown
in the figure mentioned above (even though the node labels are wrong for PLANE82).
Other mid-side node movement is not allowed.




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