*HEADING
: EIGENVALUE ANALYSIS OF AN UNCONSTRAINED 1-ELEMENT MESH  [S8R]
*PREPRINT,ECHO=YES,HISTORY=NO,MODEL=NO
*NODE
1    , 0.        , 0.
3    , 7.        , 0.
7    , 0.        , 7.
9    , 7.        , 7.
*NGEN
1,3
3,9,3
7,9
1,7,3
*ELEMENT,TYPE=S8R, ELSET=EALL
1    , 1    , 3    , 9    , 7    , 2    , 6    , 8    , 4
*SHELL SECTION,MATERIAL=A1, ELSET=EALL
 .1, 3
*MATERIAL,NAME=A1
*ELASTIC
3.E6      , 0.3
*DENSITY
7.5E-4, 
*STEP
*FREQUENCY, eigensolver=lanczos, SIM=NO
15, , ,-1.E7
*OUTPUT,HISTORY,FREQUENCY=1
*MODAL OUTPUT
*END STEP