After you defined the substructure generation step or steps for your analysis, you must define a Retained nodal dofs boundary condition for a substructure. The retained degrees of freedom for a substructure node are the degrees of freedom that are external and are available for use in the analysis; all other degrees of freedom for the specified node are assumed to be internal to the substructure and do not factor into the analysis. When you import a substructure from this analysis into a model for substructure usage, Abaqus/CAE displays these nodes as light blue crosses, which enables you to pick them easily from a part instance or assembly.
If you want to apply a load to the substructure at a location other than its retained degrees of freedom, you can define a load case in the substructure generation step.
