table.spectrum

Syntax

l = table.spectrum(t,fDamp,fPMin,fPMax,in)

Get the displacement response spectrum, the pseudo-velocity response spectrum, and the pseudo-acceleration spectrum from an input acceleration stored in table t.

fDamp is the damping constant for the response analysis. The calculation is only approximate for amped responses; the higher fDamp is, the less accurate the response.

The range of periods over which the spectrum is calculated is given by the fPMin and fPMax arguments, and the number of points in the output list is defined by n.

Returns a list with three entries. Entry 1 is the displacement response spectrum, 2 is the pseudo-velocity response spectrum, and entry 3 is the pseudo-acceleration response spectrum.

Each entry is a list of 2D vectors with the X component being a period.

The algorithm was adapted from Craig (1981).

Returns:l - A list three long - the displacement, pseudo-velocity, and pseudo-acceleration spectrum. Arguments:t - integer name, string name, or table pointer

Reference

Craig, R. R., Jr. Structural Dynamics - An Introduction to Computer Methods. New York: John Wiley and Sons (1981).