I have a linear static model with 2D 1st order elements that runs without any errors or warnings. However, when I convert the elements to second order, I get a fatal error because some of the midside nodes have a high R3 rotation. I was wondering what the cause for this error might be?
thanks in advance!
This is probably due to the fact that PARAM, K6ROT does not add drilling stiffness to parabolic shells. You did not have R3 singularities with the linear elements because K6ROT added stiffness to those dof.