Define Ramp Dialog Box

Set up a multi-stage temperature ramp for the cross-linking. Each interval (stage) consists of a linear temperature ramp, in which a cross-linking step is performed, the temperature is incremented, and the system is equilibrated at the new temperature.

To open this dialog box, click the Define Ramp button in the Crosslink Polymers Panel.

  • Using
  • Features
  • Additional Resources

Using the Define Ramp Dialog Box

The temperature schedule consists of a set of intervals, in which the temperature changes linearly between an initial temperature and a final temperature in a specified number of steps. At each step, a crosslinking is performed, followed by a simulation at the temperature for the step to equilibrate the system at that temperature after the crosslinking (an iteration). The temperatures at the ends of the intervals are included in the number of steps performed.

The schedule does not have to be continuous, i.e. if you plot the temperature vs simulation time, it is a continuous set of line segments. For example, you can have a schedule that consists of 50 steps at 700 K followed by 50 steps at 300 K, by setting the initial and final temperature in each interval to the same value (700 K in the first interval, 300 K in the second interval).

When constructing a continuous schedule, note that a crosslink/equilibrate iteration is performed at the final temperature of each interval and at the initial temperature of the next interval, so you would have two consecutive iterations performed at the same temperature if these temperatures are set to the same value. So if you wanted a schedule that heated from 300 K to 700 K in steps of 10 K and then cooled from 700 K back to 300 K in steps of 10 K, you could set the initial and final temperatures for the first interval to 300 K and 700 K, with 41 steps, and set the initial and final temperatures for the second interval to 690 K and 300 K, with 40 steps; this would avoid repeating a step at 700 K. As another example, to construct a schedule in which the temperature rises from 300 K to 700 K in steps of 10 K, and does 50 steps at 700 K, you could set the initial and final temperatures for the first interval to 300 K and 690 K, with 40 steps, and set the initial and final temperatures for the second interval to 700 K and 700 K, with 50 steps. Alternatively, you could set the initial and final temperatures for the first interval to 300 K and 700 K, with 41 steps. Then you could set the initial and final temperatures for the second interval to 700 K and 700 K, with 49 steps rather than 50, as one step has already been performed at 700 K in the previous interval.

Define Ramp Dialog Box Features

Load Ramp button

Load a ramp from your user resources. Opens the Load Ramp dialog box, where you can choose a ramp by name from a menu.

Add Interval button

Add a new interval to the ramp. A new column is added to the right of the existing columns in the ramp table.

Ramp table

In this table, you set the values that define each interval of the ramp. The table rows and the settings you can make with them are described below. You can rearrange the columns by dragging the header to the desired location.

Initial temperature (K) Initial temperature for the interval.
Final temperature (K) Final temperature for the interval. When you set the value, the initial temperature in the next column is automatically set to the same value, to allow continuity of the temperature schedule. The schedule does not have to be continuous, however.
Temperature increment (K) The increment in temperature at each step in the interval. The value is set based on the initial and final temperatures and the number of steps: (Tfinal-Tinitial)/(steps−1).
Steps (N ps/step) Number of temperature steps in the interval. The temperature for each step is interpolated linearly between the initial and final temperatures. The number of steps includes the initial and final temperature. One crosslinking and equilibration operation (iteration) is performed at each step. The simulation time for the step (reported in parentheses) is set in the parent panel.
Interval time (ps) Total amount of simulation time for the interval (number of steps × N ps)
Total time (ps) Total cumulative amount of simulation time for all intervals up to and including the current interval.
Max crosslinks per iter Maximum number of crosslinks that are permitted in any iteration in this interval. One iteration is performed at each temperature step.
Potential crosslinks Maximum possible number of crosslinks up to and including this interval.
Time step (fs) Time step to use in the simulations. At higher temperatures, a shorter time step ensures that atoms do not move too far in the step.
Delete column Delete the column from the schedule.
Save Ramp button

Save the ramp in your user resources. Opens the Ramp Name dialog box, where you can give a name to the ramp, in the Workflow name text box.

Extend final interval until target saturation is reached option

Continue the crosslinking and equilibration at the final temperature of the final step until the target saturation is reached.

Reset button

Reset the panel to its initial state.

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