TABLED1

Bulk Data Entry

TABLED1 – Dynamic Load Tabular Function, Form 1

Description

Defines a tabular function for use in generating frequency-dependent and time-dependent dynamic loads.

Format

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
TABLED1	TID	XAXIS	YAXIS
	x1	y1	x2	y2	x3	y3	x4	y4
	x5	y5	…	…	…	…	…	…

Example

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
TABLED1	32
	-3.0	6.9	2.0	5.6	3.0	5.6	ENDT

Field	Contents
TID	Table identification number. No default (Integer > 0)
XAXIS	Specifies a linear or logarithmic interpolation for the x-axis. See comment 6. Default = LINEAR (LINEAR or LOG)
YAXIS	Specifies a linear or logarithmic interpolation for the y-axis. See comment 6. Default = LINEAR (LINEAR or LOG)
x#, y#	Tabular values. No default (Real, or ENDT)

Comments

xi must be in either ascending or descending order, but not both.
Discontinuities may be specified between any two points except the two starting points or two end points. For example, in figure 1 discontinuities are allowed only between points x2 through x7. Also, if y is evaluated at a discontinuity, the average value of y is used. In figure 1, the value of y at x = x3 is y = (y3+y4)/2.
At least one continuation entry must be specified.
Any x, y pair may be ignored by placing 'SKIP' in either of the two fields used for that entry.
The end of the table is indicated by the existence of 'ENDT' in either of the two fields following the last entry. An error is detected if any continuations follow the entry containing the end-of-table flag 'ENDT'.
The TABLED1 uses the algorithm: $image\table11.gif$

where x is input to the table and y is returned. The table look-up is performed using interpolation within the table and linear extrapolation outside the table using the two starting or end points. See figure 1. The algorithms used for interpolation or extrapolation are:

$image\table12.gif$

where xj and yj follow xi and yi.

No warning messages are issued if table data is input incorrectly.

$image\table13.gif$

Figure 1. Example of Table Extrapolation and Discontinuity

Linear extrapolation is not used for Fourier transform methods. The function is zero outside the range of the table.
For frequency-dependent loads, x# is measured in cycles per unit time.
Tabular values on an axis if X-Axis or Y-Axis = LOG must be positive. A fatal message will be issued if an axis has a tabular value < 0.

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