Defining Explicit Dynamic Steps

You can define an explicit dynamic step to perform a stress analysis of problems with relatively short dynamic response times or of extremely discontinuous events and processes.

You can create an explicit dynamic step with automatic time incrementation to have the simulation adjust the size of the time increments to solve problems effectively and efficiently. In most cases, the default automatic incrementation scheme is preferred because it selects increment sizes based on computational efficiency. If you have considerable experience with a particular problem, you might be able to select a more economical approach by using fixed time incrementation to manually specify the time increment.

This task shows you how to:

See Also
About Explicit Dynamic Steps
In Other Guides
Analysis Cases and Steps

Define Explicit Dynamic Steps Using Solver's Default Time Incrementation

  1. From the Procedures section of the action bar, click Explicit Dynamic Step .
  2. Optional: Enter a descriptive Name.
  3. Enter a value as the Step time, which is the duration of the step.
  4. Expand the Incrementation section.
  5. From the Incrementation type options, select Solver default.
  6. Expand the Continuation Data section to indicate whether you want to write continuation data that allows you to run subsequent restart simulations from this step.
  7. From the Save data options, select one of the following:
    OptionDescription
    None Generates no continuation data.
    Evenly spaced intervals Generates and saves continuation data at evenly spaced intervals throughout the step.
  8. If you chose that the app generate and save continuation data:
    1. Enter a value as the Intervals.

      The value that you enter represents the number of intervals during the step at which the restart data is to be written.

    2. From the Save at options, select one of the following:

      Option Description
      Next closest increment Generates the continuation data at the increment ending immediately after the time dictated by the specified number of intervals.
      Exact intervals Generates the continuation data at the exact times dictated by the specified number of intervals.

    3. From the Interval data to keep options, select one of the following:

      Option Description
      All Stores the data generated at all the specified increments of this step.
      Last saved Stores only the continuation data generated at the last increment of this step.

  9. Expand the Advanced section.
  10. Optional: Select Include geometric nonlinearity to account for nonlinear effects caused by large displacements and deformations.

    If you enable this option, it remains active during all subsequent steps in the simulation.

  11. Optional: Select Include adiabatic heating effects to specify that an adiabatic stress analysis is to be performed.

    This option is relevant for metal plasticity only.

  12. Click OK.

Define Explicit Dynamic Steps Using Automatic Time Incrementation

  1. From the Procedures section of the action bar, click Explicit Dynamic Step .
  2. Optional: Enter a descriptive Name.
  3. Enter a value as the Step time, which is the duration of the step.
  4. Expand the Incrementation section.
    1. From the Incrementation type options, select Automatic.
      The solver determines the size of each increment automatically.
    2. Enter a value as the Scale factor to scale the time increment computed by the Abaqus solvers.
    3. Select Element by element to estimate the stable time increment element by element.

      Element-by-element estimates generally require more increments and more computational time than the global time estimator.

    4. Optional: Select Improved DT method to estimate the stable time increment for three-dimensional continuum elements and for elements with plane stress formulations.
    5. Enter a value as the Maximum time increment.

      If you do not specify a value, the app does not impose a limit.

  5. Expand the Continuation Data section to indicate whether you want to write continuation data that allows you to run subsequent restart simulations from this step.
  6. From the Save data options, select one of the following:
    OptionDescription
    None Generates no continuation data.
    Evenly spaced intervals Generates and saves continuation data at evenly spaced intervals throughout the step.
  7. Enter a value as the Intervals.

    The value that you enter represents the number of intervals during the step at which the restart data is to be written.

  8. If you chose that the app generate and save continuation data:
    1. From the Save at options, select one of the following:

      Option Description
      Next closest increment Generates the continuation data at the increment ending immediately after the time dictated by the specified number of intervals.
      Exact intervals Generates the continuation data at the exact times dictated by the specified number of intervals.

    2. From the Interval data to keep options, select one of the following:

      Option Description
      All Stores the data generated at all the specified increments of this step.
      Last saved Stores only the continuation data generated at the last increment of this step.

  9. Expand the Advanced section.
  10. Optional: Select Include geometric nonlinearity to account for nonlinear effects caused by large displacements and deformations.

    If you enable this option, it remains active during all subsequent steps in the simulation.

  11. Optional: Select Include adiabatic heating effects to specify that an adiabatic stress analysis is to be performed.

    This option is relevant for metal plasticity only.

  12. Click OK.

Define Explicit Dynamic Steps Using Fixed Time Incrementation

  1. From the Procedures section of the action bar, click Explicit Dynamic Step .
  2. Optional: Enter a descriptive Name.
  3. Enter a value as the Step time, which is the duration of the step.
  4. Expand the Incrementation section.
    1. From the Incrementation type options, select Fixed.
      The solver uses a constant increment size that you specify.
    2. Enter a value as the Scale factor to scale the time increment computed by the Abaqus solvers.
    3. Optional: Select Improved DT method to estimate the stable time increment for three-dimensional continuum elements and for elements with plane stress formulations.
    4. Enter a value as the Maximum time increment.

      If you do not specify a value, the app does not impose a limit.

  5. Expand the Continuation Data section to indicate whether you want to write continuation data that allows you to run subsequent restart simulations from this step.
  6. From the Save data options, select one of the following:
    OptionDescription
    None Generates no continuation data.
    Evenly spaced intervals Generates and saves continuation data at evenly spaced intervals throughout the step.
  7. If you chose that the app generate and save continuation data:
    1. Enter a value as the Intervals.

      The value that you enter represents the number of intervals during the step at which the restart data is to be written.

    2. From the Interval data to keep options, select one of the following:

      Option Description
      All Stores the data generated at all the specified increments of this step.
      Last saved Stores only the continuation data generated at the last increment of this step.

  8. Expand the Advanced section.
  9. Optional: Select Include geometric nonlinearity to account for nonlinear effects caused by large displacements and deformations.

    If you enable this option, it remains active during all subsequent steps in the simulation.

  10. Optional: Select Include adiabatic heating effects to specify that an adiabatic stress analysis is to be performed.

    This option is relevant for metal plasticity only.

  11. Click OK.

Define Explicit Dynamic Steps Using Direct Time Incrementation

  1. From the Procedures section of the action bar, click Explicit Dynamic Step .
  2. Optional: Enter a descriptive Name.
  3. Enter a value as the Step time, which is the duration of the step.
  4. Expand the Incrementation section.
    1. From the Incrementation type options, select Direct.
    2. Enter a value as the Time increment.
  5. Expand the Continuation Data section to indicate whether you want to write continuation data that allows you to run subsequent restart simulations from this step.
  6. From the Save data options, select one of the following:
    OptionDescription
    None Generates no continuation data.
    Evenly spaced intervals Generates and saves continuation data at evenly spaced intervals throughout the step.
  7. If you chose that the app generate and save continuation data:
    1. Enter a value as the Intervals.

      The value that you enter represents the number of intervals during the step at which the restart data is to be written.

    2. From the Interval data to keep options, select one of the following:

      Option Description
      All Stores the data generated at all the specified increments of this step.
      Last saved Stores only the continuation data generated at the last increment of this step.

  8. Expand the Advanced section.
  9. Optional: Select Include geometric nonlinearity to account for nonlinear effects caused by large displacements and deformations.

    If you enable this option, it remains active during all subsequent steps in the simulation.

  10. Optional: Select Include adiabatic heating effects to specify that an adiabatic stress analysis is to be performed.

    This option is relevant for metal plasticity only.

  11. Click OK.