The basic procedure for setting up a simulation that uses the Narayanaswamy model to calculate the residual stresses and deformations is fairly straightforward. First of all, create a transient task with the appropriate geometric attributes. Then perform the following steps:
Create a sub-task for the simplified viscoelastic flow problem.
Create a sub-task
Select the appropriate problem from the Create a sub-task menu.
Residual stresses and deformations (Narayanaswamy)
When prompted, specify a name for the sub-task.
Specify the region where the sub-task applies.
Domain of the sub-task
Define the material properties.
Material data
Specify the density.
Specify the thermal conductivity.
Specify the heat capacity per unit mass.
Specify the average temperature, presently used as initial temperature.
Specify the heat source per unit volume.
Define the data for Narayanaswamy model.
Data for Narayanaswamy model
Define the bulk relaxation modulus (Equation 26–4).
Bulk relaxation modulus
The bulk relaxation modulus is defined as a Prony series (
terms) plus a constant (asymptotic) value, and
requires 
parameters. You have to specify the asymptotic
value, as well as the number of modes (up to 8) and the
corresponding parameters. You have the option of changing the
entire spectrum or one mode only. Define the shear relaxation modulus (Equation 26–5).
Shear relaxation modulus
The shear relaxation modulus is defined as a Prony series (
terms) plus a constant (asymptotic) value, and
requires 
parameters. You have to specify the asymptotic
value, as well as the number of modes (up to 8) and the
corresponding parameters. You have the option of changing the
entire spectrum or one mode only. Define the structural relaxation modulus (Equation 26–9).
Structural relaxation modulus
The structural relaxation modulus is defined as a Prony series (
terms), and requires 
parameters. You have to specify the number of
modes (up to 8) and the corresponding parameters. You have the
option of changing the entire spectrum or one mode only. Define the shift function (Equation 26–6 and Equation 26–7).
Shift function
Specify the parameters for the Narayanaswamy function, together with the associated parameters—namely, the ratio
of activation energy to the ideal gas
constant, the fractional parameter 
, the reference temperature 
, and the absolute zero temperature
expressed in the current temperature units.
Define the glassy dilation function.
Glassy dilation function
Specify the glassy dilation function, which can be a third-order polynomial function of the temperature.
Define the liquid dilation function.
Liquid dilation function
Specify the liquid dilation function, which can be a third-order polynomial function of the temperature.
Define the thermal boundary conditions.
Thermal boundary conditions
By default, temperature is imposed on all boundaries. For all boundary sides, the only possibilities are Temperature imposed, Flux density imposed, or Insulated boundary. See Boundary Conditions and Problem Setup for details.
Define the displacement boundary conditions.
Displacement boundary conditions
By default, vanishing displacements are imposed on all boundaries. For all boundary sides, you can impose a combination of normal/tangential displacement and force, as well as symmetry (when geometrically relevant). See item 6 in Problem Setup for details.
Important: Note that inflow boundary conditions should be selected at inlet(s) with the flow rate, as this is the only way of imposing a relevant boundary condition for the viscoelastic variable.
(optional) Modify the interpolation scheme for temperature.
Interpolation
You only have access to the interpolation for the temperature. Low-level (and therefore computationally cheap) interpolation is selected for the stress unknowns and auxiliary fields.