*Heading
2D model of Box with Air
Adaptive mesh used to update Air
2D continuum elements tested
**------------------------------------------------
*Node
*Element, type=AC2D4
*Elset, elset=AIR-1__I1
*solidsection, elset=AIR-1__I1, material=AIR
** ----------------------------------------------------------------
*Node
*Element, type=CPS4
*Elset, elset=BOX-1__I1
*solidsection, elset=BOX-1__I1, material=SOLID
*surface, type=ELEMENT, name=AIR
AIR_S1, S1
AIR_S2, S2
AIR_S4, S4
AIR_S3, S3
*surface, type=ELEMENT, name=SOLID-S
SOLID-S_S4, S4
SOLID-S_S1, S1
SOLID-S_S2, S2
*tie, name=AIR-SOLID, adjust=YES
AIR, SOLID-S
**
** Assembly Nsets
**
*Nset, nset=AIR
*nset,nset=cload1
*Nset, nset=RIGHT
*Nset, nset=LEFT
*Nset, nset=LOAD
*nset,nset=retained,unsorted
*Nset, nset=OUT_AIR
*Nset, nset=OUT_BOX
*Nset, nset=SIR_S
*Nset, nset=SOLID_S
*Nset, nset=SET10
**
** Assembly Elsets
**
*Elset, elset=AIR
*Elset, elset=SIR_S
*Elset, elset=SOLID_S
*Elset, elset=AIR_S1
*Elset, elset=AIR_S2
*Elset, elset=AIR_S3
*Elset, elset=AIR_S4
*Elset, elset=SET10
*Elset, elset=SOLID-S_S1
*Elset, elset=SOLID-S_S2
*Elset, elset=SOLID-S_S4
*material, name=AIR
*acousticmedium
*density
1.1E-3,
*material, name=SOLID
*density
0.01,
*elastic
100, 0.
*boundary
LEFT, 1, 2
RIGHT, 1, 2
**------------------------------------------------
*Step, perturbation
*frequency,norm=mass
189,,,100
*boundary,op=new
retained,1,2
*output, field
*node output
u,
*endstep
**------------------------------------------------
*STEP,NLGEOM
*SUBSTRUCTURE GENERATE,type=z101,overwrite,library=box_ac2d4_moddyn,
mass matrix=yes,recovery=yes
*BOUNDARY,op=new
*substructure load case,name=load91
*cload
cload1,2,100
*RETAINED NODAL DOFS,SORTED=NO
retained,
*RETAINED EIGENMODES, GENERATE
*SUBSTRUCTURE MATRIX OUTPUT,mass=yes,sload=yes,file=box_ac2d4
*END STEP