The Multiplier Table Editor is a utility that can be used to easily create load curves for loads in time-dependent analyses. This utility can be accessed by pressing the Curve button or View / Edit Load Curve button in the load dialog. (The name of the button may vary from load to load or analysis type to analysis type.) The number in the Load Curve field will be the number of the load curve that will be created in the Multiplier Table Editor. If you enter a number of an existing load curve, that curve will appear in the editor. If you enter a number of a nonexistent load curve, an empty load curve will be passed to the editor. After a load curve is created in the Multiplier Table Editor, you can also view it in the Analysis Parameters dialog.
There are numerous ways to create the input for the load curve.
Define the equation you want to use in the Equation field. Use X as the variable. You can use one of the predefined functions below by clicking on it and dragging it into the Equation field or by typing it.
For example, the equation 5*SIN(3.25*(2*p)*X) would generate a sine curve with an amplitude of 5, and a frequency of 3.25 Hz. For a Start X of 0, End X of 0.33, and Interval of 0.01, the generated curve would be just over once cycle (1/3.25 Hz = 0.308 seconds) with 30 data points in the cycle.
If the Overwrite Nodes check box is activated, the Equation Editor will erase all the data points when you change the equation and use only the data points created by the new equation. To create a piecewise function with different equations during different time periods, deactivate this option.
Table 1: Functions for Equation Editor
( ) | Parentheses to group expressions. |
^ | Raise a value to a power |
* / + | Multiplication, division, addition, and subtraction |
ABS | This function will take the absolute value of the argument. |
ARCCOS | This function will take the inverse cosine of the argument. The result is in radians. |
ARCOSH | This function will take the inverse of the hyperbolic cosine of the argument. The result is in radians. |
ARCSIN | This function will take the inverse sine of the argument. The result is in radians. |
ARCTAN | This function will take the inverse tangent of the argument. The result is in radians. |
ARSINH | This function will take the inverse of the hyperbolic sine of the argument. The result is in radians. |
ARTANH | This function will take the inverse hyperbolic tangent of the argument. The result is in radians. |
COS | This function will take the cosine of the argument, in radians. |
COSH | This function will calculate the hyperbolic cosine of the argument. The equation used is: ![]() |
DEG | This function will multiply the argument by a factor of ![]() |
EXP | This function will raise the constant e to the argument. |
INT | This function will truncate the value after the decimal point for all values in the argument. Therefore, if the argument in this function is 1.2345, the output of this function would be 1.0. |
LN | This function will take to natural logarithm of the argument. |
LOG | This function will calculate the logarithm (base 10) of the argument. |
P | The value of pi (3.1415926). |
RAD | This function will multiply the argument by a factor of ![]() |
SIN | This function will take the sine of the argument, in radians. |
SINH | This function will calculate the hyperbolic sine of the argument. The equation used is: ![]() |
SQR | This function will take the square root of the argument. |
TAN | This function will take the tangent of the argument. The quotient of the sine value and the cosine value. |
TANH | This function will take the hyperbolic tangent of the argument. The quotient of the hyperbolic sine value and the hyperbolic cosine value. |
Since the load curve data needs to be in ascending order, use the Sort button to sort the rows as necessary.