COMSOL 6.2 - Adiabatic Heating

Add an node to model abrupt changes in temperature due to fast deformation. The increase in temperature is then defined by solving the distributed equation

here, 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.

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

Enter the Tini. The default value is 293.15 K.

The density ρ is taken from the material model (Linear Elastic Material, Nonlinear 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 solid.Wc and due to viscoplasticity under the variable solid.Wvp. Here solid denotes the name of the physics interface node.

Select a — , , or .

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The method is not available with the Layered Shell interface nor with the Layered Linear Elastic Material in the Shell and Membrane interfaces.

The method corresponds to the backward Euler method except for the Layered Shell interface or when the Layered Linear Elastic Material is used. Domain ODEs are solved in these cases.

For the method, enter the following settings:

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. To determine the maximum number of iteration in the Newton loop when solving the local equation.

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. To check the convergence of the local equation based on the step size in the Newton loop.

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. To check the convergence of the local equation based on the step size in the Newton loop. The final tolerance is computed based on the current solution of the local variable and the entered value.

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. To check the convergence of the local equation based on the residual.

If both a step size and residual convergence check is requested, it is sufficient that one of the conditions is fulfilled. Setting either the and or the to zero ignores the corresponding convergence check. An error is returned if all are set to zero.

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.