COMSOL 6.2 - Adiabatic Heating

The node adds the equations for adiabatic heating in layered shells caused by abrupt changes in temperature due to fast deformation.

The increase in temperature is then defined by solving the distributed equation

where ρ is the density, Cp is the heat capacity at constant pressure, T is the temperature field, βah is the coefficient of adiabatic heating, and Qh corresponds to the heat sources due to mechanical dissipative processes.

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

If the Composite Materials Module is available, adiabatic heating can be applied to arbitrary layers. The material properties, orientations, and layer thicknesses are defined using node. The offset, and local coordinate system, in which material orientations and results are interpreted, is defined by or node.

Without the Composite Materials Module, only single layer shells and membranes can be modeled. This is still useful, for example for some multiphysics couplings. For single layer materials, an ordinary node can be used, as long you include a property group in which, for example, the thickness is given.

It is only possible to select boundaries which are part of the selection of a layered material defined in or node.

Select the layers in which adiabatic heating is to be modeled.

Table 6-61: Layer Selection
Selection	Use All Layers	Selection of Individual Layers
Boundary	Default when added.	When Use all layers is not selected. Only a subset of the layers selected in the parent can be selected.

If the same layer is selected in two nodes being active on the same boundary, the contributions will be exclusive

	For a general description of this section, see Layer and Interface Selections in the documentation for the Composite Materials Module.

Enter the Tini. The default value is 293.15 K.

The density ρ is taken from the material model (Linear Elastic Material or Hyperelastic Material).

The default Cp uses values . For , enter an expression or value. The default value for the is 0 J/(kg·K).

Enter the , βah. The default value is 1 (dimensionless), which means that dissipative processes contribute 100% as heat sources.

Select the — or .

The list makes it possible to include specific heat sources for the adiabatic heating. Enter a value or expression for the heat source Qh to include. For instance, the dissipated energy density due to creep is available under the variable shell.Wc and due to viscoplasticity under the variable shell.Wvp. Here solid denotes the name of the physics interface node.

The method is not available with the Layered Shell interface neither with the Layered Linear Elastic Material nor the Layered Hyperelastic Material in the Shell and Membrane interfaces.

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 this field can affect the convergence of the overall solution.

Physics tab with selected: