EMODIF,ALL! Elements which have the absorbing material on the floor ! Boundary conditions ALLS
NSEL,S,LOC,X,0.0 NSEL,A,LOC,Y,0.0 NSEL,A,LOC,X,LEN NSEL,A,LOC,Y,HGT
D,ALL,UX,,,,,UY,UZ! Constrain all displacements to zero at the walls LOCAL,11,1,27,20 NSEL,A,LOC,X,RAD ESLN ESEL,INVE TYPE,2 MAT,3
EMODIF,ALL! Interior elements are specified as Type=2 & material=3 ALLS
! Fluid-Structure Interface (FSI)
NSEL,S,LOC,X,RAD ! Select interface (FSI) surface nodes ESLN! Select elements attached to interface surface
SF,ALL,FSI! Specify vibrating surface as Fluid-structure interface NROTAT,ALL
D,ALL,UX,.01! Radial vibration amplitue of Vibrating surface D,ALL,UY,,,,,UZ
! Impedance Surface (IMPD)
CSYS,0 ALLS
NSEL,S,LOC,X,0.0 NSEL,A,LOC,X,LEN NSEL,A,LOC,Y,0.0 NSEL,A,LOC,Y,HGT
SF,ALL,IMPD,1! Specify the walls as Impedance Surface flag ! to activate absorption ALLS FINISH /SOLU
! Excitation Frequency for Harmonic Analysis HARF,80,80! Frequency of excitation = 80 Hz SOLVE FINISH
! Plot the Standing Wave Pattern (f = 80 Hz) /POST1
/SHOW,ENCL1,GRPH,1
SET,1,1! plot the real part of pressure response EPLOT /EDGE,1
/TITLE,-ROOM ACOUSTICS-* REAL PART OF PRESSURE PLNS,PRES
SET,1,1,,1! plot the imag. part of pressure response
/TITLE,-ROOM ACOUSTICS-* IMAG. PART OF PRESSURE PLNS,PRES FINISH