Thin Layer
Use the Thin Layer node to apply elastic and damping conditions between two parts, either on an interior boundary or between two boundaries forming a pair, or a thin cladding on external boundaries to a solid.
Pair Selection
If this node is selected from the Pairs menu, choose the pair on which to apply this condition. An identity pair has to be created first.
Boundary Properties
Select a Thin layer type — Nonlayered or Layered. If the Thin Layer node is selected from the Pairs menu, this setting is not applicable.
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For Nonlayered (the default), enter the thin layer Thickness Lth.
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For Layered, and when Use all layers is selected, all information is taken from the definitions made in the Single Layer Material, Layered Material Link, or Layered Material Stack nodes under the Materials node in the current component.
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For Layered, and when Use all layers is not selected, the Layered material list is displayed. You can select from the current component:
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 Any Single Layer Material available under the Materials node.
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Any Layered Material Link available under the Materials node.
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 Any Layered Material Stack available under the Materials node.
In the COMSOL Multiphysics Reference Manual: Single Layer Materials, Layered Material Link, and Layered Material Stack
If this node is selected from the Pairs menu, select the Thickness definition — From geometry or User defined.
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For User defined (the default), enter the thin layer Thickness Lth.
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For From geometry, the thin layer thickness is calculated from the actual gap distance in the geometry. This setting can only be used if there is a nonzero gap across the entire pair selection. The gap distance and the curvature of the boundaries are expected to be small.
Thin Layer
Select the thin layer Approximation — Solid, Membrane, or Spring. Only the Solid approximation is available for Layered structures, and only the Solid or Spring approximations are available when the thin layer is selected from the Pairs menu.
By adding the following subnodes to the Linear Elastic Material, Nonlinear Elastic Material, or Hyperelastic Material nodes you can incorporate many effects in thin layers:
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Thermal Expansion (for Materials)
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Hygroscopic Swelling
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Initial Stress and Strain
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External Stress
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External Strain
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Inelastic Strain Rate
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Damping
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Viscoelasticity
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Plasticity
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Creep
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Viscoplasticity
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Damage
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Mullins Effect
When the Spring approximation is chosen, it is possible to specify a Spring Material for the thin layer.
The Thin Layer node and subnodes are only available with some COMSOL products (see https://www.comsol.com/products/specifications/).
The Thin Layer node is available in 3D, 2D, and 2D axisymmetry.
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Modeling Thin Layers in the Structural Mechanics Modeling chapter.
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Thin Layers in the Structural Mechanics Theory chapter.
Location in User Interface
Context Menus
Solid Mechanics>Thin Layer
Solid Mechanics>Pairs>Thin Layer
Ribbon
Physics tab with Solid Mechanics selected:
Boundaries>Thin Layer
Pairs>Thin Layer