I have a laminate consisiting of four plies, two isotropic plies sandwiched between 2 orthotropic plies. I have defined two materials i.e. one isotropic and other orthrotropic. i want to know factor of safety of this part to be included in a report. hence I want to know von mises stresses in isotropic plies and failure index (tsai wu) in this case for orthotropic plies. 
but in results, Abaqus wont let me show results of von mises stress in isotropic plies, i changed location i.e.bottom, top, middle etc as well. Some pictures and cae, jnl files are attached for reference. Please. 
how can i find von mises stresses in isotropic layer so that i find Factor of safety by comparing it with its yield strength. 

Note: when I define only plies, i.e. one orthotropic and other isotropic. both, von mises in istorpic ply and failure index in orthotropic ply are calculate easily. but adding isotropic plies more than creates a problem.