*HEADING
: EIGENVALUE ANALYSIS OF AN UNCONSTRAINED PATCH OF ELEMENTS  [CPS4I]
*PREPRINT,ECHO=YES,HISTORY=NO,MODEL=NO
*NODE
*NGEN
*ELEMENT,TYPE=CPS4I, ELSET=EALL
*SOLID SECTION,MATERIAL=A1, ELSET=EALL
.001,
*MATERIAL,NAME=A1
*ELASTIC,TYPE=ISOTROPIC
1.E6,.25
*DENSITY
7.5E-4,
*NSET,NSET=SIDES,GENERATE
*STEP
*FREQUENCY, eigensolver=lanczos
7, , ,-1.E7
*MODAL FILE
*OUTPUT,HISTORY,FREQUENCY=1
*MODAL OUTPUT
*END STEP
*STEP,NLGEOM
*STATIC
*DLOAD
1, P1, -10000.
2, P4, -10000.
4, P2, -10000.
5, P3, -10000.
*BOUNDARY
10,1,2
20,2
*EL PRINT,FREQ=0
*NODE PRINT
U,RF
*END STEP
*STEP,NLGEOM
*FREQUENCY, eigensolver=lanczos
7, , , -1.E+7
*MODAL FILE
*OUTPUT,HISTORY,FREQUENCY=1
*MODAL OUTPUT
*EL PRINT,FREQ=0
*NODE PRINT,FREQ=0
*BOUNDARY,OP=NEW
*END STEP