Inelastic Strain Rate

The node allows to enter inelastic strain contributions to the , , and models on a variety of formats. As opposed to the External Strain feature, the inelastic contribution is given as a strain rate, and the inelastic contribution is added after integrating this rate in time.

The node is only available with some COMSOL products (see https://www.comsol.com/products/specifications/)

Shell Properties

This section is only present when is used as a subnode to:

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in the Layered Shell interface. See the documentation for the node in the Layered Shell chapter.

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and in the Shell interface. See the documentation for the Inelastic Strain Rate node in the Shell and Plate chapter.

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in the Membrane interface. See the documentation for the Inelastic Strain Rate node in the Membrane chapter.

Coordinate System Selection

Select a . All inputs are interpreted in the given coordinate system. This also implies that external code should assume that strains are passed with its local orientations. Deformation gradients are rotated by the local system in both indices.

Inelastic Strain

Select the type of — , , , or .

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The option is not available for a or .

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The options , , and are not available with the in the Shell interface.

Initial value

Enter an initial value for the inelastic quantity as specified by the setting.

Time Stepping

This section is not present when is used with:

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The Layered Shell interface.

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The and in the Shell interface.

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The in the Membrane interface.

In the above cases, the domain ODEs method is always used.

Select a — , , or .

Automatic

The option corresponds to the backward Euler method except with predefined settings for the Newton loop used to solve the local equations.

Backward Euler

For the method, enter the following settings:

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. To determine the maximum number of iterations in the Newton loop when solving the local time-dependent equations.

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. To check the convergence of the local equations based on the step size in the Newton loop.

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. To check the convergence of the local equations based on the step size in the Newton loop. The final tolerance is computed based on the current solution of the local variable and the entered value.

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. To check the convergence of the local equations based on the residual of each equation.

If both a step size and residual convergence check is requested, it is sufficient that either of the conditions are fulfilled. Setting either the and or the to zero ignores the corresponding convergence check. An error is returned if all are set to zero.

Domain ODEs

No settings are needed for the method. However, this method adds degrees-of-freedom that are solved as part of the general solver sequence. The scaling of these fields can affect the convergence of the overall solution


	See also Inelastic Strain Rate in the Structural Mechanics Theory chapter.

Location in User Interface

Context Menus

Ribbon

Physics tab with , , , or node selected in the model builder tree: