ANSYS modeling of dissimilar mateials - non-zero shear stresses on free-edge!

Dear iMechanica community,

I am a metallugist interested in ANSYS modeling of metal ceramic joints - particularly the singularity at the free-edge. I have created a polar mesh that many in the literature (see below for references) suggest in order to capture the r^(-w) singularity where 0

However, the Sx and especially the Sxy values are non-zero on the free-edge and the Sx and particularly Sxy values do not give the same value for the singularity as the Sy. I studied a simple case and compared it with analytically calculated value of the singularity 'w' and they match well with Sy but are in error by 10% for Sx and 50% for Sxy. This also correlates well with the higher Sxy values found on the free-edge.

所以,我的问题是——我丢失些简单的东西? How to make ANSYS give me zero free-edge stresses, since I am hoping that this would solve the singularity issue above and also correct the shear stress prediction at the interface. Please advise. Thank you very much.

The literature is copious on this topic, starting from the 1960s till recent times.

References: Please see links below - the NASA papers (1-2 below) gives you the FEM polar mesh modeling near the singularity. This problem is a classic one and I think the composite community routinely handles this problem.

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19820016426_1982016426.pdf

http://www.sciencedirect.com/science/article/pii/004579498290030X

http://scholar.google.co.in/scholar?hl=en&q=dissimilar+material+joint+munz&btnG=

http://www.sciencedirect.com/science/article/pii/0045794989902629

http://www.sciencedirect.com/science/article/pii/0045794981900791