3. Nonlinear possibilities

Attention, this modeling is only accessible from STAT_NON_LINE. It cannot be used with MECA_STATIQUE or by manual assembly.

3.1. Laws of behavior

All the laws of behavior that can be used on continuous meshes make physical sense for these models and are assignable as long as they are accessible from COMPORTEMENT in STAT_NON_LINE (Cf. [U4.51.11]).

A law of behavior is specific to this modeling (dedicated to the calculation of limit load, cf. [R7.07.01]):

/'NORTON_HOFF'

Supported models: D_ PLAN_INCO_UPG, AXIS_INCO_UPG

3.2. Deformations

The available deformations, used in behavioral relationships under the keyword DEFORMATIONpour the operators STAT_NON_LINE and DYNA_NON_LINEsont (Cf. [U4.51.11]):

/'PETIT'

The deformations used for the behavioral relationship are the linearized deformations.

/'SIMO_MIEHE'

/'GDEF_LOG'

Allows calculations in large plastic deformations to be carried out.

3.3. Newton’s method

For solving the problem using the Newton-Raphson method, the elastic matrix is not available. It is therefore necessary to use the operators STAT_NON_LINE and DYNA_NON_LINE under the keyword NEWTONpour (Cf. [U4.51.11]):

/PREDICTION = 'TANGENTE'

The prediction phase is carried out with the tangent matrix.

/MATRICE = 'TANGENTE'

The matrix used for global iterations is the tangent matrix.

Note:

The formulation used leads to non-positive matrices and current solvers do not always know how to solve the linear systems associated with them well. In case of convergence difficulties, it may therefore be useful to test the other solvers available in the code or the other renumbering methods (cf. [U4.50.01]).