/ALE/GRID/SPRING
Block Format Keyword Grid nodes are connected with nonlinear springs (those springs have no effect on the material, only on the movement of the grid).
Format
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/ALE/GRID/SPRING  
$\text{\Delta}{t}_{0}$  $\gamma $  $\eta $  $\nu $  
V_{min} 
Definition
Field  Contents  SI Unit Example 

$\text{\Delta}{t}_{0}$  Typical time
step. (Real) 
$\left[\text{s}\right]$ 
$\gamma $  Nonlinearity
factor. Default = 0.0 (Real) 

$\eta $  Damping
coefficient. Default = 0.5 (Real) 

$\nu $  Shear factor. Default = 1.0 (Real) 

V_{min}  Element with a volume less
than V_{min} will be
declared. Default = 10^{30} (Real) 
$\left[{\text{m}}^{3}\right]$ 
Comments
 This option is available for 3D analysis only.
 Further explanation about this formulation can be found in ALE Formulation in the Radioss Theory Manual.
 Effective time step
$\text{\Delta}{t}_{0}^{*}$
is computed using damping parameter:$$\text{\Delta}{t}_{0}^{*}=\frac{\text{\Delta}{t}_{0}}{\eta +\sqrt{1+{\eta}^{2}}}$$