*HEADING
: MODEL CHANGE ACOUSTICS TESTS  [AC3D20]
*PREPRINT,ECHO=YES,MODEL=YES,HISTORY=YES
*NODE, Nset=ODB_NSET
1, 
41,,10.
1001,1.
1041,1.,10.
2001,,,1.
2041,,10.,1.
3001,1.,,1.
3041,1.,10.,1.
4001,,,.5
4041,,10.,.5
5001,1.,,.5
5041,1.,10.,.5
*NGEN,NSET=NALL1
1,41
2001,2041
*NGEN,NSET=NALL2
1001,1041
3001,3041
*NFILL,NSET=ALL_NODES
NALL1,NALL2,2,500
*NGEN,NSET=NALL3
4001,4041
5001,5041
*ELEMENT,TYPE=AC3D20,ELSET=ALL_ELEMENTS
1,1,1001,1005,5,2001,3001,3005,2005,501,1003,505,3,2501,3003,2505,
2003,4001,5001,5005,4005
*ELGEN,ELSET=ALL_ELEMENTS
1,10,4,1
*ELSET,ELSET=SECOND,GENERATE
6,10
*MATERIAL,NAME=AIR
*DENSITY
1.293, 
*ACOUSTIC MEDIUM,BULK MODULUS
1.42176E5, 
*SOLID SECTION,MATERIAL=AIR,ELSET=ALL_ELEMENTS
*NSET,NSET=RECRD,GEN
1,21
*NSET,NSET=DRIV
1,1001,2001,3001
**************************************
*Elset,Elset=ODB_ESET
SECOND, ALL_ELEMENTS
**
**
*Nset, Nset=ODB_NSET
ODB_NSET, ALL_NODES, RECRD, DRIV
**
**
*STEP
*STEADY STATE DYNAMIC,DIRECT
1., 
*IMPEDANCE
10,I5,
*BOUNDARY
DRIV,8,,1.
*NODE PRINT,NSET=RECRD
POR,PPOR
*NODE FILE,NSET=RECRD
POR,PPOR
*OUTPUT,FIELD,VARIABLE=PRESELECT,OP=ADD,FREQUENCY=9999
*OUTPUT,FIELD, OP=ADD
*NODE OUTPUT,NSET=RECRD
POR,
*OUTPUT,HISTORY,OP=ADD
*NODE OUTPUT,NSET=RECRD
POR,
*ENDSTEP
**************************************
*STEP
*STATIC
1,1
*MODEL CHANGE,REMOVE
SECOND,
*ENDSTEP
**************************************
*STEP
*STEADY STATE DYNAMIC,DIRECT
1., 
*IMPEDANCE,OP=NEW
5,I5,
*BOUNDARY
DRIV,8,,1.
*NODE PRINT,NSET=RECRD
POR,PPOR
*NODE FILE,NSET=RECRD
POR,PPOR
*OUTPUT,FIELD, OP=ADD
*NODE OUTPUT,NSET=RECRD
POR,
*OUTPUT,HISTORY,OP=ADD
*NODE OUTPUT,NSET=RECRD
POR,
*ENDSTEP