# PARAM, ALPHA1

Bulk Data Entry Adds Rayleigh damping to viscous damping for structural mesh.

Parameter Values Description
ALPHA1 <Real>

Default = 0.0

PARAM, ALPHA1 is used in frequency response, transient response and modal complex eigenvalue analyses.

If PARAM, ALPHA1 and/or PARAM, ALPHA2 are not equal to zero, then Rayleigh damping is added to the viscous damping. ALPHA1 is the scale factor applied to the mass matrix and ALPHA2 to the structural stiffness matrix as in:

$\left[B\text{'}\right]=\left[B\right]+ALPHA1\cdot \left[M\right]+ALPHA2\cdot \left[K\right]$