Using Activation Attribute

Using Activation Attribute

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What is Activation and How to use it in COMSOL Multiphysics

Use the Activation sub-node to activate or deactivate parts of a domain according to an Activation expression that you define. The Activation sub-node uses a scale factor that reduces the elastic stiffness and density of the material, to emulate that material is not present. When the Activation expression is satisfied, the material is activated in a state of zero stress. In this tip Thermal Stresses in a Layered Plate CMS is used to illustrate it.

When the material is not active, the following is done to emulate that the material is not present:

  • The elasticity matrix is multiplied by the Activation scale factor.
  • The density is multiplied by the square of the Activation scale factor.

When the material is activated, the following is done to ensure that the activation is stress-free:

  • Elastic strains at the instant of activation are removed from the total strains.
  • Initial stresses are always removed, regardless of the Activation expression.

The Activation sub-node can be used in combination with Linear Elastic Material.

Activation 1

  1. In the Physics toolbar, click Attributes and choose Activation.
  2. In the Settings window for Activation, locate the Domain Selection section.
  3. Click Clear Selection.
  4. Select Domain 1 only.

Locate the Activation section. In the Activation expression text field, type para>1.

01 - Using Activation Attribute


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Computational Modeling and Simulation is the simulation center of Acamech that models Mechanical Engineering Problems, especially Multiphysics Simulation; including Fluid Flow (CFD), Structural Mechanics, Acoustics, Heat Transfer as a unique Multiphysics problem. We use COMSOL Multiphysics, MATLAB, and Autodesk Inventor.

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