Decohesion

Using the subnode, you can add decohesion properties to a contact pair. This functionality requires that an subnode is present and active in the same parent node.

The selection of the node is the same as that of its parent node. There can only be one node under a specific node.

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

The adhesive stresses are defined as boundary tractions with respect to the selected coordinate system. The selection is limited to boundary systems. Make sure that the tangents of the selected boundary system are well defined on all destination boundaries.

Select a — or to choose the type of variable that controls the damage process.

Select a — , , , or . The definition of these differ between the two cohesive zone models, and the last option is available only for .

For the displacement-based damage models, enter:

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, Gct. This is the energy released during the whole decohesion process in a state of pure tension.

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, Gcs. This is the energy released during the whole decohesion process in a state of pure shear.

For the separation law, also enter the , λ.

When the traction separation law is , , or , select the to be either or . In either case, enter the α. The mixed mode criterion determines how normal and shear components are combined into a single scalar failure criterion. For the separation law, the mixed mode criterion is always linear (equivalent to a power law with α= 1.)

For the energy-based damage models, enter:

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, G0t. This is the elastic energy at the onset of damage in pure tension.

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, G0s. This is the elastic energy at the onset of damage in pure shear.

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, Gct. This is the energy released during the whole decohesion process in a state of pure tension.

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, Gcs. This is the energy released during the whole decohesion process in a state of pure shear.

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, α0. The value determines how normal and shear components are combined into a single scalar criterion for damage initiation.

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, αc. The value determines how normal and shear components are combined into a single scalar failure criterion.

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, N. This parameter adjusts the shape of the traction separation law. It is available for the and options. By default, N = 1; a smaller value gives a smoother behavior.

In the list, it is possible to add a viscous delay to the damage growth for time-dependent studies. Do this by selecting and enter a value for the , τ.

To display this section, click the button (

) and select in the dialog box.

determines the residual stiffness of the adhesive layer after decohesion. By default, dmax = 1, which means that no residual stiffness remains. Enter a value smaller than 1 to introduce some residual stiffness.

Select to compute and store to the energy dissipated by damage.