*HEADING
360 DEGREES MODEL CORRESPONDING TO B21 ELEMENTS
*PREPRINT, ECHO=YES, MODEL=YES, HISTORY=YES
*NODE,NSET=NALL
1, 50, 0
2, 25, 25
3, 0, 50
4, -25, 25
5, -50,0
6, -25, -25
7, 0, -50
8, 25, -25
*ELEMENT,TYPE=B21, ELSET=EALL
1, 1, 2
2, 2, 3
3, 3, 4
4, 4, 5
5, 5, 6
6, 6, 7
7, 7, 8
8, 8, 1
*BEAM SECTION,SECTION=PIPE,MATERIAL=MAT, ELSET=EALL
10.,1.
0,0,-1
*MATERIAL,NAME=MAT
*ELASTIC
10E8,0.3
*DENSITY
100, 
*STEP
*FREQUENCY,EIGENSOLVER=LANCZOS, SIM=NO
10,
*OUTPUT, FIELD, FREQUENCY=0
*END STEP