*HEADING
 B21 with *BEAM FLUID INERTIA 
 1. Frequency extration
*preprint,model=yes,history=yes,echo=yes
*NODE,NSET=NALL
   1,  0.,   0.
  11,  0., 300.
*NSET,NSET=TIP
 11,
*ELEMENT,TYPE=B21,ELSET=BEAM
 1, 1,11
*BEAM SECTION,SECTION=CIRC,MAT=MAT,
ELSET=BEAM,ROTARY INERTIA=EXACT
 3.,
 0.,0.,-1.
*BEAM FLUID INERTIA
 6.0E3, 0.,0.,3.,1.0
*MATERIAL,NAME=MAT
*ELASTIC
 30.E8, 
*DENSITY
 80. 
*BOUNDARY
 1, 1,2
 1, 6,6
*ELSET,ELSET=EALL
 BEAM,
*STEP,INC=1000
*DYNAMIC, ALPHA=0.0
 .0001,.0010
*BOUNDARY,type=velocity
 11, 1,1,100.0
*OUTPUT,FIELD,VAR=PRESELECT
*OUTPUT,HISTORY,FREQUENCY=1
*NODE OUTPUT,NSET=NALL
 RF,
*END STEP