Irreversible Transformation

Three models are available to define the material transformation. Select the — (default), , or . The first two models use integral forms over time to express the fraction of transformation θit as a function of temperature, while you can set it manually with the third option.

For , select the type of analysis — (default) or , depending on the expected temperature variations. See the Parameters section for the additional settings specific to each type of analysis.

For , define the parameters used in the Arrhenius equation to calculate the degree of transformation (see Arrhenius Kinetics for more details):

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A in the Arrhenius equation. Default is taken . For enter a value or an expression.

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ΔE in the Arrhenius equation. Default is taken . For enter a value or an expression.

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n of the (1−α) factor to define a polynomial Arrhenius kinetics equation.

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L to define the enthalpy variation associated with the transformation. The following heat source is added to the right-hand side of Equation 6-15 in Solid node:

Enter values or expressions for the L and the θit to define the heat source associated with the transformation as:

Choose a ,which can point to any material in the model. The default uses the . The properties before transformation are the ones specified in the and sections of the parent Solid node. The effective material properties are dynamically updated with the transformation evolution.

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Tit, h to define the (high) temperature that the solid needs to reach to start getting transformed.

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tit, h to define the time needed for the complete transformation to happen while the temperature is above Tit, h.

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Lit, h to define the enthalpy variation associated with transformation due to overheating. The following heat source is added to the right-hand side of Equation 6-15 in Solid node:

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Tit, c to define the (low) temperature that the solid needs to reach to start getting transformed.

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tit, c to define the time needed for the complete transformation to happen while the temperature is below Tit, c.

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Lit, c to define the enthalpy variation associated with transformation due to overcooling. The following heat source is added to the right-hand side of Equation 6-15 in Solid node:

This section is available when the check box is selected.

Select a kd — (default) or , to be used for transformed solid. For choose , , , or based on the characteristics of the thermal conductivity and enter another value or expression in the field or matrix.

When the material and spatial frames differ (due to the presence in the model of a node, or a Solid Mechanics physics interface for example), you can select on which frame the kd is specified.

By default the is set to . With this option, the thermal conductivity is supposed to be given on the material frame. If the material frame does not coincide with the spatial frame, a conversion is applied to get the variables ht.k_dxx, ht.k_dyy, and so on. This option is often suitable for moderate elastic strains.

By selecting the option, the thermal conductivity is supposed to be given on the spatial frame. In case of isotropic materials, the thermal conductivity variables ht.k_dxx, ht.k_dyy, and so on, are directly equal to the values you have set. In case of anisotropic materials, the rotation of the material is also taken into account following

where R is the rotation matrix between the material and the spatial frames.

This section is available when the check box is selected.

Select a ρd and Cp, d — (default) or , to be used for transformed solid. The heat capacity describes the amount of heat energy required to produce a unit temperature change in a unit mass.

This section is available when the is set to or . Set a value or expression for the , αinit, to be used as an initial condition for any of the time integral analyses.