*HEADING
   Verification of damping proportional to the rotary intertia
   And test of Multiple load Cases for R2D2,MASS,SPRING2,Rotary1 elements
*NODE
1, 
2, 3., 
11, 0., -1.  
12, 3., -1. 
99, 1.,
*ELEMENT, TYPE=R2D2, ELSET=RIGID
90, 1, 2
*ELEMENT, TYPE=MASS, ELSET=MASS 
91, 99
*ELEMENT, TYPE=ROTARYI, ELSET=INERTIA 
92, 99
*ELEMENT, TYPE=SPRING2, ELSET=LEFT
1, 1, 11
*ELEMENT, TYPE=SPRING2, ELSET=RIGHT
2, 2, 12 
*RIGID BODY, ELSET=RIGID, REF NODE=99
*MASS, ELSET=MASS
18000.0, 
*ROTARY INERTIA, ELSET=INERTIA, ALPHA=1.0 
0., 0., 36.0e+3 
*SPRING, ELSET=LEFT
2, 2 
1.0e+5 , 
*SPRING, ELSET=RIGHT
2, 2 
2.0e+5 , 
*BOUNDARY 
99, 1, 2, 0.0 
11, 1, 2, 0.0
12, 1, 2, 0.0
*STEP, NLGEOM
The system is initially disturbed slowly with 10degree rotation about Z-axis. 
*STATIC
1.0e-6, 1.0e-6, 
*BOUNDARY
99, 6, 6, 0.17453293
*NODE PRINT
U, 
RF,
*EL PRINT
S,
 E ,
*END STEP
**
*STEP,PERTURBATION
*STATIC
*LOAD CASE,NAME="stretch in x direction"
*BOUNDARY
99,1,1,6
*END LOAD CASE
*LOAD CASE,NAME="stretch in y direction"
*BOUNDARY
99,2,2,6
*END LOAD CASE
*OUTPUT,FIELD
*ELEMENT OUTPUT
S,E
*NODE OUTPUT
U, 
*END STEP