Subcase Information Entry The CNTNLSUB command can be used to continue a nonlinear solution from a preceding nonlinear subcase, and thus create complex loading sequences.




Argument Options Description
option <YES, NO, SID>


If CNTNLSUB does not exist in the input file, the default is NO.

If CNTNLSUB exists in the input file, but a value is not specified, the default is YES.

This nonlinear subcase continues the nonlinear solution from the nonlinear subcase immediately preceding it.
"Preceding" refers to the sequence of subcases in the deck, and not the subcase numbering. If CNTNLSUB,YES is used within a subcase, the preceding subcase must be nonlinear subcase of the same type. If CNTNLSUB,YES is used above the first subcase, then all the consecutive nonlinear subcases of the same type will continue each other (however, other types of subcases interspersed between nonlinear ones will "break" the continuation sequence).
This nonlinear subcase executes a new solution sequence starting from the initial, stress-free state of the model. 1
SID Subcase ID
This nonlinear subcase continues the nonlinear solution from SUBCASE SID. SUBCASE SID must precede the current subcase in the deck and must be a nonlinear subcase of the same type. 1


  1. This command applies only to nonlinear subcases. Nonlinear subcases may only be continued from other nonlinear subcases of the same analysis type.
  2. Only one CNTNLSUB entry can be defined for each subcase.
  3. If CNTNLSUB = option is present above the first subcase, it is applied to all nonlinear subcases. (CNTNLSUB = SID is only allowed within a subcase).
  4. CNTNLSUB is mostly relevant in path-dependent problems, such as plasticity or gap/contact analysis with friction/stick. In these problems, subcase continuation can be used to create complex loading paths that will typically produce very different results than simple proportional loading of a single subcase. CNTNLSUB also affects the convergence history and, to some extent, the results in problems that typically are not path-dependent, such as gap/contact analysis without friction.
  5. If displacement boundary conditions (zero or non-zero SPC or SPCDs) or forces applied to a preceding subcase (Subcase 1) are removed in the continued nonlinear subcase (Subcase 2), then they are converted into equivalent internal forces at the beginning of Subcase 2 and are ramped down gradually. This effect can be observed in the SPCFORCE, TOTALFORCE, OLOAD and GPFORCE output requests.
  6. If the deformed shape resulting from the preceding subcase should be unchanged in the subsequent subcase, then the D field should be set to F on the SPC or SPCD entries. Retaining the deformed shape by setting the D field to F on the SPC/SPCD entry is supported for both analysis and optimization.