*HEADING
: EIGENVALUE ANALYSIS OF AN UNCONSTRAINED PATCH OF ELEMENTS  [B22]
*NODE
 201,
 207,10.0
*NGEN
 201,207
*ELEMENT,TYPE=B22
 201,201,202,203
*ELGEN,ELSET=ALL
 201,3,2,1
*BEAM SECTION,SECTION=RECT,ELSET=ALL,MATERIAL=MAT
 0.1,0.1
*MATERIAL,NAME=MAT
*ELASTIC
 30E6,0.0
*DENSITY
7.5E-4, 
*STEP,PERTURBATION
*FREQUENCY, eigensolver=lanczos, SIM=NO
9, , ,-1.E4
*NODE PRINT
 U,
*END STEP