3.1.12.2. Modal Damping Command

modalDamping $factor

Argument	Type	Description
$factor	float	damping factor.

Example:

1. Tcl Code

set N 2 ;# Number of modes for modal damping
eigen $N

modalDamping 0.05 0.02 ;# 5% in mode 1, 2% in mode 2

Further reading about Modal Damping can be seen in [ChopraMcKenna2015]

Warning

Modal damping implementation is as in Perform3D. The tangent matrix is not modified for damping terms as this would result in a full matrix. Instead just the right hand side of the equation, i.e. the resisting force vector is modified. As a consequence, iteration is required at each step to obtain a converged solution, i.e. no Linear solution algorithm or explicit time stepping algorithms will work correctly with modal damping!