The sawtooth time history function is a periodic function. A single cycle of a sawtooth function is defined by seven points (time, function value). Those seven points, in order, are (0, 0), (Ramp time, Amplitude), (0.5 * Period - Ramp time, Amplitude), (0.5 * Period, 0), (0.5 * Period + Ramp time, -Amplitude), (Period - Ramp time, -Amplitude) and (Period, 0). The figure below illustrates a single cycle of a sawtooth time history function and the seven points.
Time History Function Name edit box. Use the default or specify another name for the time history function by typing directly in the edit box.
Parameters
Period edit box. Use the default or enter the period of the sawtooth function. It is the time in seconds that it takes for the function to complete one cycle.
Ramp Time edit box. Use the default or enter the time that it takes for the sawtooth function to ramp up from a function value of 0 to its maximum amplitude.
Number of Cycles edit box. Use the default or enter the number of cycles in the function.
Amplitude edit box. Use the default or enter the maximum function value of the sawtooth function.
Define Function area. This area displays the time and values for the function. They cannot be edited and are provided for review purposes only. These values update when changes are made to the items in the Parameters area of the form. If manual changes to this area are necessary, click the Convert to User-Defined button to convert the function to a user-defined function, which will make this area editable.
Function Graph area. This area displays a graph of the function. It updates automatically as additional points are defined for the function. In some cases it may be necessary to click the Display Graph button after making changes to the form to display or update the graphical display.
Run the mouse pointer over the function graph and a dot appears along the line representing the time history function. The coordinates of the dot are reported in the box just below the graph.
Access the Time History Function Definition - Sawtooth form as follows:
Click the Define menu > Functions > Time History command to access the Define Time History Functions form. Then do one of the following:
Select Sawtooth from the Choose Function Type to Add drop-down list; click the Add New Function button.
Highlight an existing Sawtooth function definition in the Functions display area and click the Modify/Show Spectrum button.