*HEADING
: EIGENVALUE ANALYSIS OF AN UNCONSTRAINED 1-ELEMENT MESH  [ELBOW31]
*NODE,NSET=ALL
1,0.
2,15.
*ELEMENT,TYPE=ELBOW31, ELSET=EALL
1,1,2
*BEAM SECTION,SECTION=ELBOW,TEMPERATURE=VALUES,MATERIAL=MAT1, ELSET=EALL
10.,1.,0.
15.,1.
3,18,6
*MATERIAL,NAME=MAT1
*ELASTIC
3.E6,.3
*DENSITY
7.5E-4, 
*BOUNDARY
ALL,NODEFORM
*STEP
*FREQUENCY, eigensolver=lanczos, SIM=NO
9, , ,-1000000.
*OUTPUT,field,freq=0
*MODAL OUTPUT
*END STEP