General > Create_Damping

`Create_Damping`

## Purpose

setup damping matrix of structural model

## Synopsis

`C = Create_Damping (type,Kf,Ml,zeta,mode)`

## Description

CREATE_DAMPING setup damping matrix of structural model C = CREATE_DAMPING (TYPE,KF,ML,ZETA,MODE) function sets up damping matrix C according to character variable TYPE for a structure with free dof stiffness matrix KF and free dof lumped mass vector ML; the damping matrix is calibrated so that the mode numbers in row vector MODE have damping ratios as specified in row vector ZETA; the character variable TYPE should be either 'StifProp', 'Caughey' or 'Modal' Note: Caughey with one mode reduces to a mass proportional damping matrix and with two modes reduces to Rayleigh damping; for more than 2 modes Caughey damping works only if Ml is fully populated; Modal damping refers to the method of superposing modal damping matrices by Wilson/Penzien; reference: Chopra, Dynamics of Structures, 2nd edition, pp. 455-463

## Cross-Reference Information

This function calls:

- EigenMode determines eigenfrequencies and eigenmodes of structural model

- Add_Damping2State setup damping matrix of structural model as field of data structure STATE