*HEADING
: EIGENVALUE ANALYSIS OF AN UNCONSTRAINED PATCH OF ELEMENTS  [PIPE22H]
*NODE
*NGEN
*ELEMENT,TYPE=PIPE22H
*ELGEN,ELSET=ALL
*BEAM SECTION,SECTION=PIPE,ELSET=ALL,MATERIAL=MAT
 0.1,0.01
*MATERIAL,NAME=MAT
*ELASTIC
 30E6,0.0
*DENSITY
7.5E-4,
*STEP,PERTURBATION
*FREQUENCY, eigensolver=lanczos, SIM=NO
9, , ,-1.E7
*NODE PRINT
 U,
*OUTPUT,HISTORY,FREQUENCY=1
*MODAL OUTPUT
*END STEP