/DAMP

Format 1 (Short Format)

/DAMP/damp_ID

α $\beta$

Format 2 (Full Format)

/DAMP/damp_ID

$\begin{array}{l}{\alpha }_x{\beta }_x\\ {\alpha }_y{\beta }_y\\ {\alpha }_z\beta z\\ {\alpha }_{xx}{\beta }_{xx}\\ {\alpha }_{yy}{\beta }_{yy}\\ {\alpha }_{zz}{\beta }_{zz}\end{array}$

Definition

Comments

1. Rayleigh α damping computation:(1)
   $$C=\alpha M+\beta K$$
   (2)
   $$C_i=\alpha m_i+\beta k_i$$
   (3)
   $${\text{C}}_{\text{crit}}=\sqrt{4{\text{m}}_{\text{i}}{\text{k}}_{\text{i}}}$$
   (4)
   $$\frac{{\text{C}}_{\text{i}}}{{\text{C}}_{\text{crit}}}=\frac{\alpha }{2{\omega }_{\text{i}}}+\frac{{\beta \omega }_{\text{i}}}{2}$$
   Where,

   $C$

   Damping matrix

   $M$

   Mass matrix

   $K$

   Stiffness matrix

   α and $\beta$

   Coefficients

   $C_i$

   Nodal damping matrix

   $m_i$

   Nodal mass matrix

   $k_i$

   Nodal stiffness matrix

   $C_{crit}$

   Critical damping

2. This option can be used only if damping card (/DAMP) is defined in the Runname_0000.rad file.
3. Arbitrary coefficients alpha and beta may be declared in the Runname_0000.rad file and modified when repeating the option in the Radioss Engine file Runname_run#.rad.