In a bizarre way, Abaqus does not generate error or warning when the model of the cracked plate under static load run successfully but the assigned seam crack does not open totally. The only part of the crack open. Also, you can see one element node has separated from the adjacent element just close to the seam crack.
The model runs successfully for crack length =< plate thickness. I got a problem (inaccurate & unreasonable results, the crack does not open as assigned to in the model) for longer cracks.
I did not find in the documentation any restriction on using the seam crack.
in the current case, the crack region partitioned through thickness to control a number of elements through the thickness. when using a uniform number of an element (no transition in the mesh size) the model works well but the number of elements will be so excessive in thick plate.