Phase Transformation Strain Multiphysics Coupling
The Phase Transformation Strain multiphysics coupling () is used to include phase transformation strains that are produced by a phase transformation physics interface as an inelastic strain contribution to the total strain in the Solid Mechanics interface.
Note that if Enable thermal strains has been selected at the Metal Phase Transformation interface level, thermal strain effects are included in the phase transformation strains. In this situation no Thermal Expansion coupling should be used between Solid Mechanics and Heat Transfer in Solids.
Settings
The Label is the default multiphysics coupling feature name.
The Name is used primarily as a scope prefix for variables defined by the coupling node. Refer to such variables in expressions using the pattern <name>.<variable_name>. In order to distinguish between variables belonging to different coupling nodes or physics interfaces, the name string must be unique. Only letters, numbers, and underscores (_) are permitted in the Name field. The first character must be a letter.
The default Name (for the first multiphysics coupling feature in the model) is ptstr1.
Domain Selection
When the coupling is added, selected entities in the coupled Solid Mechanics and Metal Phase Transformation interfaces are included by default.
Coupled Interfaces
This section defines the physics involved in the multiphysics coupling. The Metal Phase Transformation and Solid Mechanics lists include all applicable physics interfaces.
The default values depend on how the coupling node is created.
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If the node is added from the Physics ribbon (Windows users), Physics contextual toolbar (macOS and Linux users), or context menu (all users), then the first physics interface of each type in the component is selected as the default.
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If it the node added automatically when a multiphysics interface is selected in the Model Wizard or Add Physics window, then the two participating physics interfaces are selected.
See also the Theory for Phase Transformation Strains
Time Stepping for Strains
This section is used to specify how TRIP strains and plastic strain recovery are computed. Under Method, select Local ODEs or Domain ODEs. For Local ODEs, the TRIP strains and the plastic recovery are computed using state variable based local Newton iterations, and no additional degrees of freedom are added to the model. For Domain ODEs, the TRIP strains and the plastic recovery are computed using domain level ODEs, and corresponding degrees of freedom are added to the model.
Advanced Settings
To enable this section, click the Show More Options button () and select Show Advanced Physics Options in the Show More Options dialog. The section is shown if the selected Method under Time Stepping For Strains is Local ODEs. Normally these settings do not need to be changed.
For the Local ODEs method, you can make the following settings:
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Maximum number of local iterations. This defines the maximum number of iterations of the Newton loop when solving the local strain equations.
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Absolute tolerance. This defines the absolute tolerance for convergence of the local strain equations. Convergence is judged based on the step size, that is, the size of the Newton correction, of each equation.
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Relative tolerance. This defines the relative tolerance for convergence of the local strain equations. Convergence is judged based on the step size, that is, the size of the Newton correction, of each equation.