Impact process of a lunar lander

Beijing Institute of Technology | Ming-Jian Li

The following APDL code is a companion code for the course on Artificial Intelligence and Simulation Science. Its function is to calculate the process of impact energy absorption between the honeycomb structure on the underside of a lunar lander and the lunar surface using the finite element method, utilizing a geometric source file websurf.igs (click to download). The following code needs to be executed in ANSYS, APDL is the parameteric language of ANSYS.

x
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fini
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/clear
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/FILNAME,moonlander,1 
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!    by Ming-Jian Li 
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/units,SI
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/dscale,1,1.0   
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! input geometric model
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/AUX15  
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IOPTN,IGES,SMOOTH   
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IOPTN,MERGE,NO  
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IOPTN,SOLID,NO  
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IOPTN,SMALL,NO  
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IOPTN,GTOLER,FILE   
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IGESIN,'websurf','igs',' '  
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/PREP7 
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hct=1       ! honeycomb thickness
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rdt=0.05    ! rigid disk thickness
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tch=3       ! truncated cone height
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tcbr=1.98   ! truncated cone bottom radius
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tctr=1.5    ! truncated cone top radius
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tct=0.01    ! truncated cone shell thickness
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asoil=5     !soil dims
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bsoil=5     
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tsoil=0.5   
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gap=0.1     !gap between soil and structure 
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hcsz=0.1    !mesh size
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hctn=10      !mesh div
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tol=1e-6    
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hcex=0.3e6  !Young's modulus
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hcmuxy=0.01 !Poisson's raio
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hcdens=270  !eff density
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soilsz=0.2    !mesh size
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vz=-1      !velocity
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! element
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et,1,solid164
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et,2,shell163
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! mat1 honeycomb
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MP,DENS,1,300   
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MP,EX,1,0.3e6
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MP,NUXY,1,0.01  
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TB,PLAW,1,,,1,  
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TBDAT,1,1e4 
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TBDAT,2,0.1e6 
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TBDAT,3,
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TBDAT,4,40  
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TBDAT,5,5   
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TBDAT,6,0.5 
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TBDAT,7,
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! mat2 shell
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edmp,rigid,2,0,0
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mp,ex,2,2e5
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mp,prxy,2,0.3
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mp,dens,2,37700
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R,1 
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RMODIF,1,1, , ,tct   ! shell thickness
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! mat3 soil
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mp,ex,3,12E6
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mp,prxy,3,0.3
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mp,dens,3,1600
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! mat4 rigid disk
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edmp,rigid,4,0,0
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mp,ex,4,2e5
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mp,prxy,4,0.3
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mp,dens,4,27700
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! mat5 rigid ground
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edmp,rigid,5,7,7
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mp,ex,5,12E6
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mp,prxy,5,0.3
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mp,dens,5,1600
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! change mm into m
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arscale,all, , ,0.001,0.001,0.001, ,1,1
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! move upward
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agen,2,all, , ,0,0,hct, , 0,1
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! merge lines
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numcmp,kp
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numcmp,line
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lcomb,1,2
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lcomb,3,4
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lcomb,6,7
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lcomb,11,12
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lcomb,13,14
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lcomb,16,17
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lcomb,19,20
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lcomb,22,23
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lcomb,24,25
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lcomb,30,31
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lcomb,32,33
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lcomb,35,36
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lcomb,38,39
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lcomb,41,42
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lcomb,43,44
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lcomb,48,49
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numcmp,all
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! add the rest of the surf
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*get,lmx,line,,count
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*get,amx,area,,count
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l,15,17
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al,15,16,lmx+1
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l,11,14
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al,11,12,13,lmx+2
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l,6,10
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al,6,7,8,9,lmx+3
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l,4,5
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al,4,lmx+4
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l,21,23
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al,21,22,lmx+5
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l,24,27
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al,24,25,26,lmx+6
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l,28,32
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al,28,29,30,31,lmx+7
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l,33,34
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al,33,lmx+8
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*get,kmx,kp,,count
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k,kmx+1,0,0,hct
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l,kmx+1,1
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l,kmx+1,3
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al,lmx+9,lmx+10,1,2
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alls
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! extrude honey comb & rigid disk
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alls
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lesize,all,hcsz
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lesize,lmx+9,,,2
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lesize,lmx+10,,,2
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vext,1,,,0,0,-hct
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vext,1,10,,0,0,rdt
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lsel,s,loc,z,-tol,hct-tol
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lesize,all,,,hctn
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lsel,s,loc,z,hct+tol,hct+rdt-tol
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lesize,all,,,1
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! honeycomb & rigid disk mesh
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alls
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vsel,s,,,1
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vatt,1,,1
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vsweep,all
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vsel,s,,,2,11
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vatt,4,,1
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vsweep,all
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! truncated cone
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alls
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*get,kmx,kp,,count
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*get,lmx,line,,count
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lgen,2,18,19, ,0,0,tch, , 1,0
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lsscale,lmx+1,lmx+2,,tctr/tcbr,tctr/tcbr,0,,1,1
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k,kmx+4,0,0,hct+tch
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l,kmx+1,kmx+4
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l,kmx+3,kmx+4
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al,lmx+1,lmx+2,lmx+4,lmx+3
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rdis=0.2
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lgen,2,18,19, ,0,0,tch*rdis, , 1,0
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ratio=tctr/tcbr+(1-tctr/tcbr)*(1-rdis)
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lsscale,lmx+5,lmx+6,,ratio,ratio,0,,1,1
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rdis=0.4
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lgen,2,18,19, ,0,0,tch*rdis, , 1,0
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ratio=tctr/tcbr+(1-tctr/tcbr)*(1-rdis)
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lsscale,lmx+7,lmx+8,,ratio,ratio,0,,1,1
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l,kmx+5,87
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l,kmx+6,88
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l,kmx+7,89
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l,kmx+5,kmx+8
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l,kmx+6,kmx+9
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l,kmx+7,kmx+10
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l,kmx+1,kmx+8
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l,kmx+2,kmx+9
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l,kmx+3,kmx+10
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al,130,lmx+9,lmx+5,lmx+10
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al,131,lmx+10,lmx+6,lmx+11
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al,lmx+5,lmx+12,lmx+7,lmx+13
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al,lmx+6,lmx+13,lmx+8,lmx+14
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al,lmx+7,lmx+15,lmx+1,lmx+16
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al,lmx+8,lmx+16,lmx+2,lmx+17
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! truncated cone mesh size
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lsel,s,loc,z,hct+rdt+tol,hct+tch-tol
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lesize,all,,,3
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alls
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lesize,lmx+5,,,4,,1
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lesize,lmx+6,,,4,,1
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lesize,lmx+7,,,2,,1
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lesize,lmx+8,,,2,,1
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lesize,lmx+1,,,2,,1
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lesize,lmx+2,,,2,,1
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lesize,lmx+3,,,3,,1
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lesize,lmx+4,,,3,,1
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!  truncated cone rigid shell mesh
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asel,s,loc,z,hct+rdt+tol,hct+tch+tol
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aatt,2,1,2
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amesh,all
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! complete whole model
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alls
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csys,1
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vgen,12,all, , ,0,30,0, , 0,0
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asel,s,loc,z,hct+rdt+tol,hct+tch+tol
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agen,12,all, , ,0,30,0, , 0,0
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csys,0
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!  moon soil
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alls
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block,-asoil/2,asoil/2,-bsoil/2,bsoil/2,-gap,-gap-tsoil
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*get,vmax,volu,,count
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vsel,s,,,vmax
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vatt,3,,1
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allsel,below,volu
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lesize,all,soilsz
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vmesh,all
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alls
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! merge nodes
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alls
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nummrg,node,1e-9
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alls
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*get,nodnum,node,,count
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*get,enum,elem,,count
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!create parts
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!part 1 honeycomb,2 rigid disk, 3 rigid truncated cone ,4 soil
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edpart,create,   
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! merge rigid bodies
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edcrb,add,,2,3,
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!  contact
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nsel,s,loc,z,-tol,tol
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cm,body,node
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nsel,s,loc,z,-gap-tol,-gap+tol
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cm,ground,node
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alls
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edcgen,ESTS,1,4,
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edcontact,10,0,2,0,1,1,1,4,0
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nsel,s,loc,z,-tol,hct+tch+tol
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cm,vehicle,node
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edve,velo,vehicle,0,0,vz
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*dim,time,array,2,1
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*dim,accz,array,2,1
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accz(1)=9.8/6
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accz(2)=9.8/6
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time(1)=0
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time(2)=100
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edload,add,ACLZ,,vehicle,time,accz,0 
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/sol
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nsel,s,loc,z,-gap-tsoil-tol,-gap-tsoil+tol
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d,all,ux,0
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d,all,uy,0
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d,all,uz,0
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alls
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time,0.5
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solve

The result is as follows.