When Abaqus/CAE generates the input (.inp) file for a model assembly that contains model instances, a single flattened assembly is generated. All model instance subassemblies are written as a flat list of instances under the single assembly block.

Most features from the original model of a model instance are saved in the input file, with some exceptions:

• Surface-to-surface contact and self-contact interactions defined in the initial step are the only history-level features from a model instance subassembly that are saved in the input file. The contact interaction property name and surface names are prepended with the model instance name in the main assembly; for example:

  model-instance-name#contact-property-name
  model-instance-name#Surf-1, model-instance-name#Surf-2

• Model-level features from a model instance are saved in the input file; for example, materials, section assignments, connector section assignments, skins, stringers, and orientations. Materials and element controls defined in a model instance are prepended with the model name in the main assembly; for example,

  model-name#material-name

  Connector sections assignments are prepended with the model instance name in the main assembly; for example:

  model-instance-name#Wire-3-Set-1

  Other model-level data such as initial conditions and amplitude definitions from a model instance are not saved in the input file.

• Engineering features such as mass and inertia elements, springs, and dashpots defined at the part level in the model instance are saved to the input file, but engineering features defined at the assembly level in the original model are not.

• Sets and surfaces from a model instance are saved in the input file. These set and surface names are also prepended with the model instance name in the main assembly; for example:

  model-instance-name#Set-1

• Constraints, reference points, attachment points, attachment lines, and wires from a model instance are saved in the input file.

• For constraints the model instance name will be prepended to the constraint name; for example:

  model-instance-name#constraint-name

• Attachment points, attachment lines, and wires will be available through sets created in the subassembly.

The following limitations exist:

• Generation of a flat input file is not supported for a model containing model instances.

• Restart analysis is not supported for a model containing model instances.

• Instances of models containing substructure instances are not supported.

• Instances of models containing assembled fasteners are not supported.