*HEADING
STEADY STATE VIBRATION OF 1-DOF SYSTEM (VISCOUS DAMPING)
*NODE,NSET=FILE
 1,10.
*ELEMENT,TYPE=DASHPOT1,ELSET=D
1,1
*DASHPOT,ELSET=D,DEPENDENCIES=1
 1, 
0.12,,,0.
0.24,,,1.
*ELEMENT,TYPE=SPRING1,ELSET=S
2,1
*SPRING,ELSET=S
 1, 
 30., 
*ELEMENT,TYPE=MASS,ELSET=M
3,1
*MASS ,ELSET=M
0.02588, 
*NSET,NSET=NALL
1,
*BOUNDARY
 1,2,6
******************************************************
*STEP
FIELD VARIABLE = 0 ===> VISCOUS DAMPING COEFF = 0.12
*STEADY STATE DYNAMICS,DIRECT,FREQUENCY SCALE=LINEAR
0.05, 10., 200, 1
*CLOAD
1,1,1.0
*NODE PRINT,FREQ=20
U,PU
V,
A,
*NODE FILE,F=20
V,
A,
U,
PU,
*EL PRINT,FREQ=20
S,PHS
E,PHE
*EL FILE,FREQ=20
S,PHS
E,PHE
*OUTPUT,HISTORY,OP=ADD,FREQUENCY=1
*NODE OUTPUT,NSET=NALL
U,
*OUTPUT,HISTORY,OP=ADD,FREQUENCY=20
*NODE OUTPUT, NSET=NALL
V,
A,
*ELEMENT OUTPUT,ELSET=D
S,
E,
*END STEP
******************************************************
*STEP
FREQUENCY EXTRACTION
*FREQUENCY, eigensolver=lanczos
1, , 
*END STEP
******************************************************
*STEP
 STEADY STATE DYNAMICS, SUBSPACE (1)
*STEADY STATE DYNAMICS,SUBSPACE PROJECTION,FREQUENCY SCALE=LINEAR,
 INTERVAL=RANGE
0.05, 10., 200, 1
*CLOAD
1,1,1.0
*END STEP
******************************************************
*STEP
DUMMY STEP TO CHANGE FIELD VARIABLE VALUE FROM 0 TO 1
*STATIC
1e-16,1e-16
*OUTPUT,FIELD,FREQUENCY=1
*FIELD,VARIABLE=1
NALL,1.
*END STEP
*STEP
FIELD VARIABLE = 1 ===> VISCOUS DAMPING COEFF = 0.24
*STEADY STATE DYNAMICS,DIRECT,FREQUENCY SCALE=LINEAR
0.05, 10., 200, 1
*CLOAD
1,1,1.0
*FIELD,VARIABLE=1
NALL,1.
*NODE PRINT,FREQ=20
U,PU
V,
A,
*NODE FILE,F=20
V,
A,
U,
PU,
*EL PRINT,FREQ=20
S,PHS
E,PHE
*EL FILE,FREQ=20
S,PHS
E,PHE
*OUTPUT,HISTORY,OP=ADD,FREQUENCY=1
*NODE OUTPUT,NSET=NALL
U,
*OUTPUT,HISTORY,OP=ADD,FREQUENCY=20
*NODE OUTPUT,NSET=NALL
V,
A,
*ELEMENT OUTPUT,ELSET=D
S,
E,
*END STEP
******************************************************
*STEP
 STEADY STATE DYNAMICS, SUBSPACE (2)
*STEADY STATE DYNAMICS,SUBSPACE PROJECTION,FREQUENCY SCALE=LINEAR,
 INTERVAL=RANGE
0.05, 10., 200, 1
*CLOAD
1,1,1.0
*END STEP
******************************************************