3.1.12.1. Rayleigh Damping Command

rayleigh $alphaM $betaK $betaKInit $betaKcomm

Argument	Type	Description
$alphaM	float	factor applied to elements or nodes mass matrix
$betaK	float	factor applied to elements current stiffness matrix.
$betaKInit	float	factor applied to elements initial stiffness matrix
$betaKcomm	float	factor applied to elements committed stiffness matrix

This command is used to assign damping to all previously-defined elements and nodes. When using rayleigh damping in OpenSees, the damping matrix for an element or node, D is specified as a combination of stiffness and mass-proportional damping matrices:

\(D = \alpha_m M + \beta_k K_{current} + \beta_{k_{init}} K_{init} + \beta_{K_{comm}} K_{last commit}\)

Note

• The command overwrites any existing damping coeeficients at the Elements and Nodes.

• The usage of Rayleigh damping may provide incorrect result when used with Non-Linear Time History Analysis using Concentrated Plasticity Model. [ChopraMcKenna2015]