*HEADING
EC38SRE1: EIGENVALUE ANALYSIS OF AN UNCONSTRAINED 1-ELEMENT MESH  [C3D8R]
*NODE,NSET=ALL
 1,0.,0.,0.
 2,7.,0.,0.
5,0.,7.,0.
 6,7.,7.,0.
 4,0.,0.,-7.
 3,7.,0.,-7.
8,0.,7.,-7.
 7,7.,7.,-7.
*ELEMENT,TYPE=C3D8R, ELSET=EALL
 1, 1,2,3,4,5,6,7,8
*SOLID SECTION,MATERIAL=A1, ELSET=EALL
*MATERIAL,NAME=A1
*ELASTIC
  3.E+6,0.3
*DENSITY
7.5E-4, 
*STEP
*FREQUENCY, eigensolver=lanczos
9, , ,-1.E4 
*END STEP