COMSOL 6.2 - Stabilization

Stabilization

It is common that parts in an assembly are initially unconstrained before contact forces are established in stationary and quasistatic simulations. Add a subnode to suppress rigid body motion related to such unconstrained parts.

Quasistatic Stabilization

The stabilizing forces can be applied to different geometric entities as selected in — , , or . The available options depend on the physics interface.

For and , the stabilization works by connecting springs to ground for those geometric entities. When is select, springs are instead added between the source and destination of the contact pairs of the parent node.

COMSOL Multiphysics makes an estimation of the spring stiffness k required to stabilize the contact problem. If this estimate of the stiffness is too small or large, enter a new value for the fstb.

It is essential that the stabilization forces are relaxed once contact forces are established in order not to pollute the final results of the solution. Select a — or , for how to relax the stabilization forces.

When the method is used COMSOL Multiphysics identifies when the contact pair(s) first comes in contact. The stabilization forces will then remain for a sufficient number of nonlinear iterations for contact forces to stabilize all adjacent parts after contact is established.

For the method select — , , , or , to control how the stabilization forces are relaxed.

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applies the stabilization forces for the first iteration of the nonlinear solver only. This can be useful if parts are initially in contact but require friction to be constrained.

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applies the stabilization forces for the first parameter step or time step. Enable to relax the spring stiffness with each iteration of the nonlinear solver.

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For , enter the number of parameter steps or time steps for which the stabilization forces are active. By enabling the , the spring stiffness is reduced with each step number. If is enabled, the spring stiffness is relaxed with each nonlinear iteration of the final specified step number.

For , enter a Boolean expression. When evaluated to true, the stabilization forces are active. This option can be useful to control the activation based on a specific parameter value in a continuation sweep, or at a specific time in a time-dependent solver.


	To monitor the stabilization energy added, add a Global Variable Probe of the variable <phys>.<contact_feature>.Wstb, and output probe values while solving in the Fully Coupled or Segregated solver. This setting allows you to track how stabilization relaxes with the nonlinear iterations.

Location in User Interface

Context Menus

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Physics tab with selected in the Model Builder tree: