Hi all,

ABAQUS has a really cool feature that collapses 4-node MITC elements into a 3-node element. However, I couldn't find enough technical details in how to doing it. Below is the only place where it is documented in ABAQUS Theory Manual - does anyone know any paper/books talking about it?

Degenerate elements

In general meshes it will be desirable to collapse at least some of the quadrilateral elements to triangles or to use the triangular element S3or S3R, which is in fact an internally collapsed S4R element. For this case the calculation of the membrane strains and the curvature changes proceeds along the same lines as before. The transverse shears will now be zero at the degenerate edges. Finally, calculation of all hourglass constraints will be omitted.