Create Transient Dynamics Analysis

Before you can run a dynamics analysis, you must have a Modal analysis with results. See the Modal Analysis chapter to learn more.

  1. On the main window toolbar, click the (Dynamics) icon.
  2. Click Transient in the drop-down menu.
  3. In the dialog, specify Modal results to which the analysis will be linked.
    Note:

    The modal solution must exist in the current design study. In SIMSOLID, the time integration of the equations of motion is extremely fast and all modes are always included in the analysis.

  4. Under Time span, select a radio button and enter values in the textbox to specify the time span to analyze.

    Time step size and number of time steps used is automatically determined. These inputs are not required.

  5. Specify damping in one of the following ways:
    Action Process
    Use Rayleigh damping coefficients Assume the damping matrix is proportional to the mass and stiffness matrices.
    1. Click the Rayleigh damping tab in the dialog.
    2. Specify values for F1 (Mass) and F2 (Stiffness) in the text boxes.
    Use Modal damping Specify a damping ratio for each mode.
    1. Click the Modal damping tab in the dialog.
    2. In the table, under Damping ratio, click on a value to activate a text box. Input the desired damping ratio.
      Note: You can also enter a Default damping ratio and click Apply to use the same ratio for all modes.
  6. Click OK.
    You have finished creating the transient dynamics analysis. Next, you will need to create a time function.

Create Time Function

Define amplitude versus time response curves for transient dynamics analysis.

Time functions are referenced by dynamic loads. There are multiple methods for creating time functions in SimSolid.

  1. In the Project Tree, click the Dynamics transient analysis.
  2. On the Analysis Workbench toolbar, click the icon.
    The Time function dialog will open.
  3. Use one of the following processes to create the function:
    Action Process
    Import from external CSV
    1. In the dialog, select the Import CSV button.
    2. Browse to the desired file and click Open.
      Note:

      The file contents must have a header row followed by 3 or more rows of data. Each row has three values. Values must be separated with commas. The first is the row index (point), the second is time and the third is amplitude.

      Example: the file time-value.csv contains:
      point,time,amplitude 
0,0.0,0.0 
1,0.1,1.0 
2,0.2,0.0
    Create from standard template functions
    1. In the dialog, select the Standard button.
    2. In the Function type drop-down menu, choose the desired template.
    3. For the Triangle, Rectangle, and Half-sine templates (pulses), specify Amplitude, Start, and duration.
      Tip: You may optionally define Period to make the pulse repeat for the entire time history.
    4. For the Harmonics template, define Amplitude, Frequency F, and Phase of the harmonic function.
    5. Click OK.
    Create manually
    1. In the dialog, select the Add row button. A new row will appear in the dialog's table.
    2. Click in the row under Point #, Time, orAmplitude factor to activate a textbox.
    3. Enter the desired values.
    Note:

    You can set a periodic time function by checking the option Set periodic in Create time function dialog. This will make the function repeat for the entire time history. To set a periodic function, the amplitudes at the first and the last points must be equal. The period of the function is always evaluated from 0.0 secs, except for standard time functions where the period can be defined in the dialog.

    If this option is not checked and the time span is outside the range specified in the table, the corresponding amplitude is assumed to be equal to zero.

  4. Click OK.