图2-15 橡胶垫上的应力
最后，图2-15显示最后分析得到的Von Mises应力。最终分析的应力峰值大约比第一次分析小25%。这表明考虑到几何模型的变形对流场的影响是相当显著的。
在画结构结果以前结构节点应当返回到它们原来的位置。 命令: UPCOORD,-1
GUI: Main Menu>Solution>Other>Updt Node Coord 以下为求解上述问题的命令流： /Batch,list /prep7
/sho,gasket,grph shpp,off
ET,1,141! Fluid - static mesh ET,2,56,! Hyperelastic element
!!!!!!!Fluid Structure Interaction - Multiphysics !!!!!!!Deformation of a gasket in a flowfield. !
!!!!!!!Element plots are written to the file gasket.grph.
!
!- Water flows in a vertical pipe through a construction !formed by a rubber gasket.
!- Determine the equilibrium position of the gasket and !the resulting flowfield ! !|| !||
!|----------| Boundary of \!|______| !||______gasket !||
!|----------| Boundary of \!|| !
!!1. Build the model of the entire domain: !!Fluid region - static mesh !!
!!Gasket leaves a hole in the center of the duct !!Morphing Fluid region is a user defined region around !!the gasket.The fluid mesh here will deform and be !!updated as the gasket deforms. !!
!!Parameterize Dimensions in the flow direction
!!
yent = 0.0! Y coordinate of the entrance to the pipe dyen = 1.0!Undeformed geometry flow entrance length
ysf1 = yent+dyen ! Y coordinate of entrance to the morphing fluid region
dsf1 = 0.5!Thickness of upstream
ygas = ysf1+dsf1 ! Y coordinate of the bottom of the gasket dg = 0.02!Thickness of the gasket dg2=dg/2.
ytg = ygas+dg! Y coordinate of the initial top of the gasket dsf2 = 0.5!Thickness of downsteam region
ysf2 = ytg + dsf2! Y of Top of the downstream morphing fluids region dyex =6.0!Exit fluid length
x = 0.! Location of the axisymmetricCenterline dgasr =.20!Initial span of gasket piper = 0.3! Radius of the pipe
xrgap = piper-dgasr!! radius of completely unobtructed flow passage !!
!!!Create geometry !!
rect,xrgap,piper,ygas,ytg! A1:Gasket(keypoints 1-4) rect,x,piper,ysf1,ysf2! A2: Morphing fluid region rect,x,piper,yent,ysf1! A3: Fluid region with static mesh rect,x,piper,ysf2,ysf2+dyex! A4: Fluid region with static mesh
aovlap,all
k,22,xrgap+dg2,ygas+dg2 rarc = dg2*1.1 larc,1,4,22,rarc al,6,4 adelete,7
al,6,3,22,7,8,5,21,1 !!Mesh Division information
ngap = 10! Number elements across the gap ngas = 10! Number of elements along the gasket rgas = -2! Spacing ratio along gasket
nflu = ngap+ngas! Number of elements across the fluid region raflu = -3! Space fluid elements near the walls and center nenty =8! Elements along flow - entrance raent =5! Size ratio in the inlet region
nfl1 = 20! Elements along flow - first morph.fluid. nthgas = 4! Elements in the gasket
nfl2 = 30 ! Elements along flow - second morph.fluid. next = 30! Elements along flow - exit region rext = 6! Size ratio in flow direction of outlet rafls = 12! Initial element spacing ratio - morph.fluid lesize,1,,,ngas,rgas lesize,3,,,ngas,rgas nfl11= nfl1*2+9
lsel,s,,,2,4,2! (Modify lesize of line 8 if changing gasket mesh) lesize,all,,,nthgas alls
lesize,5,,,nflu,raflu lesize,7,,,nflu,raflu lesize,9,,,nflu,raflu lesize,15,,,nflu,raflu lesize,18,,,nenty,1./raent lesize,17,,,nenty,1./raent lesize,21,,,nfl1,rafls
lesize,8,,,nfl11,-1./(rafls+3) lesize,22,,,nfl1,rafls lesize,19,,,next,rext lesize,20,,,next,rext
!!! AATT,MAT,REAL,TYPE- Set the attributes for the areas asel,s,,,1,2
aatt,2,2,2! Gasket(material 2) asel,s,,,3 cm,area2,area
alist! List area selected for further morphing asel,a,,,5,6
aatt,1,1,1! Fluid area (material 1) alls eshape,2