structure dynamic damping command

Syntax

structure dynamic damping keyword ... <range>

Primary keywords:

combined-local    local    maxwell    none    rayleigh

Set the damping scheme used by the structural elements for dynamic analysis (see Structual Element Damping for Dynamic Simulations). The following keywords are available:

combined-local f1

combined damping (see Local Damping) for all nodes in the range. The combined damping factor is f1.

local f1

local damping (see Local Damping) for all nodes in the range. The local damping factor is f1.

maxwell fd1 f1 fd2 f2 fd3 f3 <off-when-yield b >

Maxwell damping (see Maxwell Damping) for all structural elements in the range. f1 is the center frequency of the first Maxwell component and fd1 is the maximum damping ratio of the first Maxwell component; f2 is the center frequency of the second Maxwell component and fd2 is the maximum damping ratio of the second Maxwell component; f3 is the center frequency of the third Maxwell component and fd3 is the maximum damping ratio of the third Maxwell component. This command must be issued when the dynamic option is configured and turned on. If off-when-yield = on/yes/true (default), the Maxwell damping will be inactivated when the constitutive model is yielding; If off-when-yield = off/no/false, the Maxwell damping will still be active when the constitutive model is yielding. This damping automatically transfers to the conformable link whose source node belong to the structure element in the range. To separately assign or modify the dynamic damping for deformable links, see the command structure link dynamic-damping.

none

no damping for all nodes in the range. This is the default setting for dynamic mode.

rayleigh f1 f2

Rayleigh damping (see Rayleigh Damping) for all nodes in the range. The stiffness-proportional constant is f1 = beta, and the mass-proportional constant is f2 = alpha. This command must be issued when the dynamic option is configured and turned on.