ansys前处理建模阶段问题

suma1989

要建立一个长方体，但是长方体内部有一小长方体，这个小长方体的材料为另外一种材料，大长方体内除了笑长方体又是其他一种材料，大家帮忙看一下我写的是不是有问题，我感觉有问题
/PREP7
/TITLE,Room Acoustic Analysis

ET,1,SOLID45                   !壳单元 类型1
ET,2,FLUID30                   ! acoustic fluid element with ux & uy(0-Structure present at interface (unsymmetric element matrix))
ET,3,130                       ! acoustic infinite line element
!r,3,0.3,0,0
ET,4,FLUID30,,1,0              ! acoustic fluid element without ux & uy(1-No structure at the interface (symmetric element matrix))

! material properties
!材料1为铁
MP,EX,1,2.1E11
MP,DENS,1,7800
MP,NUXY,1,0.3

!材料2为空气介质
MP,DENS,2,1.21
MP,SONC,2,344

MP,DENS,3,2.35E-3   ! (Rho) density of air (lb/ft**3)
MP,SONC,3,1100.0    ! (C) speed of sound in air (ft/sec)
MP,MU,3,0.04        ! (Beta) absorption coefficient of the walls
                    ! ('Beta' should be between 0 - 1)

!building model
wprot,0,-90,0
block,-6,6,-4,4,-2,2
wprot,0,90,0
BLOCK,-0.2,0.2, -0.002, 0.002, -0.1, 0.1    !BLOCK, X1, X2, Y1, Y2, Z1, Z2

!meshing
!each of the length X 100
lesize,14,,,40,1
。。。。


lesize,20,,,4,1

VSEL,s,,,2  !select entity of number 2
VATT,1,,1   !VATT,MAT, REAL, TYPE, ESYS, SECNUM
mshkey,1    !Specifies whether free meshing or mapped meshing should be used to mesh a model.1— Use mapped meshing.
VMESH,2
alls

lesize,2,,,50,1
。。。。


lesize,12,,,10,1

VSEL,s,,,1
VATT,2,,2   !指定的材料属性为空气介质(与结构耦合)
mshkey,1
VMESH,1
alls