*HEADING
360 DEGREES MODEL CORRESPONDING TO 2X2 MESH OF S4R ELEMENTS
*PREPRINT, ECHO=YES, MODEL=YES, HISTORY=YES
*NODE
      1,          -5.,           5.
      2,         -15.,          15.
      3,         -30.,           0.
      4,         -10.,           0.
      5,           0.,          10.
      6,  1.77636E-15,          30.
      7,         -25.,          25.
      8,         -50.,           0.
      9,           0.,          50.
     10,         -15.,         -15.
     11,         -25.,         -25.
     12,           0.,         -50.
     13,  1.77636E-15,         -30.
     14,          -5.,          -5.
     15,           0.,         -10.
     16,          15.,         -15.
     17,          25.,         -25.
     18,          50.,           0.
     19,          30.,  1.77636E-15
     20,           5.,          -5.
     21,          10.,           0.
     22,          15.,          15.
     23,          25.,          25.
     24,           5.,           5.
*ELEMENT, TYPE=S4R
1, 1, 2, 3, 4
2, 2, 1, 5, 6
3, 2, 7, 8, 3
4, 7, 2, 6, 9
5, 10, 11, 12, 13
6, 11, 10,  3,  8
7, 14, 10, 13, 15
8, 10, 14,  4,  3
 9, 16, 17, 18, 19
10, 17, 16, 13, 12
11, 20, 16, 19, 21
12, 16, 20, 15, 13
13, 22, 23,  9,  6
14, 23, 22, 19, 18
15, 24, 22,  6,  5
16, 22, 24, 21, 19
*ELSE, ELSET=EALL, GENERATE
1,16,1
*NSET, NSET=NBC
  1,  4,  5, 14, 15, 20, 21, 24
*SHELL SECTION, ELSET=EALL,MATERIAL=MAT
1., 
*MATERIAL,NAME=MAT
*ELASTIC
10E8,0.3
*DENSITY
100, 
*STEP
*FREQUENCY, EIGENSOLVER=LANCZOS, SIM=NO
12,
*OUTPUT, FIELD, FREQUENCY=0
*END STEP