*Heading
*NODE,NSET=BEAMS,SYSTEM=C
********************************
*NODE,NSET=STIFFNER
*****
*NGEN,NSET=BEAMS,LINE=C
*NSET,NSET=OUT
*ELEMENT,TYPE=B21,ELSET=BEAMS
*ELGEN,ELSET=BEAMS
*ELEMENT,TYPE=B21,ELSET=STIFFNER
*SURFACE,TYPE=ELEMENT,NAME=MASTER
BEAMS,SPOS
***********************************
*INCLUDE,INPUT=acoustic_2dref_elem.inp
*INCLUDE,INPUT=acoustic_2dref_node.inp
*NSET, NSET=INNER
*ELSET, ELSET=INNER, GENERATE
*NSET, NSET=OUTER
*ELSET, ELSET=OUTER, GENERATE
*ELSET, ELSET=_INNER_S1, GENERATE
*SURFACE, TYPE=ELEMENT, NAME=SLAVE
_INNER_S1, S1
*ELSET, ELSET=_OUTER_S3, GENERATE
*SURFACE, TYPE=ELEMENT, NAME=OUTER
_OUTER_S3, S3
*TIE,NAME=COUPLING
slave,master
*MATERIAL,NAME=WATER
*DENSITY
1000.0,
*ACOUSTIC MEDIUM,BULK MODULUS
*IMPEDANCE PROPERTY,NAME=BGT_AUTO,TYPE=CIRCULAR
*SOLID SECTION,MATERIAL=WATER,ELSET=ACOUSTIC
0.1
*******************
*BEAM SECTION,MATERIAL=MAT1,ELSET=BEAMS,SECTION=RECT
0.1,0.1
*BEAM SECTION,MATERIAL=MAT1,ELSET=STIFFNER,SECTION=RECT
0.1,0.1
*MATERIAL,NAME=MAT1
*ELASTIC
207E9,0.3
*DENSITY
7800
*************************
*STEP,INC=1200
*STEADY STATE DYNAMIC,DIRECT
*IMPEDANCE
OUTER,I3,BGT_AUTO
*CLOAD
26055,2,100.0
*BOUNDARY
25001,1,1,0.0
25071,1,1,0.0
25001,6,6,0.0
25071,6,6,0.0
26055,1,1,0.0
26055,6,6,0.0
*OUTPUT,FIELD,FREQ=1
*NODE OUTPUT,NSET=BEAMS
U
*NODE OUTPUT
POR
*OUTPUT,HISTORY,freq=50
*NODE OUTPUT,NSET=out
POR
*NODE OUTPUT,NSET=inner
POR
*END STEP
*STEP,INC=1200
*STEADY STATE DYNAMIC,DIRECT
*IMPEDANCE,OP=NEW
*SIMPEDANCE
OUTER,BGT_AUTO
*CLOAD
26055,2,100.0
*BOUNDARY
25001,1,1,0.0
25071,1,1,0.0
25001,6,6,0.0
25071,6,6,0.0
26055,1,1,0.0
26055,6,6,0.0
*OUTPUT,FIELD,FREQ=1
*NODE OUTPUT,NSET=BEAMS
U
*NODE OUTPUT
POR
*OUTPUT,HISTORY,freq=50
*NODE OUTPUT,NSET=out
POR
*NODE OUTPUT,NSET=inner
POR
*END STEP
************************