Nonlinear Formulation
The Nonlinear Formulation category controls how nonlinearities are to be handled for the solution. The following options are available:
Program Controlled (default): Mechanical automatically specifies either the Full or Quasi setting as described below. The Quasi setting is based on a default Reformulation Tolerance of 5%. The Quasi option is used by default except when a Radiation load is present or if enthalpy is defined as a material property, then the Full option is automatically specified.
Full: Manually sets formulation for a full Newton-Raphson solution.
Quasi: Manually sets formulation based on a tolerance you enter in the Reformulation Tolerance field that appears if Quasi is chosen.
Note: The Quasi method is an approximation to the Full method. It is faster but not as accurate for strong nonlinearities. The Quasi method sets up a single fast material table, with equal temperature points between a maximum and a minimum temperature for evaluation of temperature-dependent material properties. Using this option, the solution uses 64 points between the maximum and the minimum temperature of the fast material table. If your material properties contain highly non-linear behavior and 64 points are not sufficient, using Full method is recommended.