Simulating effect of interference fit

- September 20, 2019 at 12:10 pm
  
  Rashi
  Subscriber
  
  Hi all,
  
  I need to do a simulation to see the effect of interference fit between two components. I can very easily do this in workbench, but I'm having some troubles to do this in APDL. For this assignment, I have to do it in APDL.
  
  The following is the results I get, which is not correct and I cannot figure out why does this happen.
  
  I have also attached the APDL code I've used.
  
  Thank you.
- September 20, 2019 at 12:11 pm
  
  Rashi
  Subscriber
  
  FINISH
  
  /CLEAR
  
  /PREP7
  
  TREF,22
  
  !set background to white
  
  /RGB,INDEX,100,100,100, 0
  
  /RGB,INDEX, 80, 80, 80,13
  
  /RGB,INDEX, 60, 60, 60,14
  
  /RGB,INDEX, 0, 0, 0,15
  
  /REPLOT
  
  !!!!!!!!!!!!!!!!!!!!!
  
  !MATERIAL DEFINITION!
  
  !!!!!!!!!!!!!!!!!!!!!
  
  !MATERIAL ID=1
  
  MP,EX,1,196e3,0 !Elastic modulas (MPa)
  
  MP,PRXY,1,0.272,0 !Poisson ratio
  
  MP,DENS,1,7.75e-9, !Density (tonne/mm3)
  
  MP,ALPX,1,1.16e-5, !CTE
  
  MP,MU,1,0.1 !Friction coefficient = 0.1
  
  !MATERIAL ID=2
  
  MP,EX,2,151e3 !Elastic modulas (MPa)
  
  MP,PRXY,2,0.27 !Poisson ratio
  
  MP,DENS,2,8.4e-9 !density (tonne/mm3)
  
  MP,ALPX,2,9.6e-6 !CTE
  
  MP,MU,2,0.1 !Friction coefficient = 0.1
  
  !!!!!!!!!!!!!!!!!!!!!!!!!
  
  !MESH ELEMENT DEFINITION!
  
  !!!!!!!!!!!!!!!!!!!!!!!!!
  
  ET,1,63 !SHAFT
  
  ET,2,63 !MAGNET1
  
  ET,3,63 !MAGNET2
  
  ET,4,63 !SLEEVE
  
  ET,5,170 !target
  
  ET,6,174 !contact
  
  KEYOPT,6,9,3 !initial penetration effect
  
  KEYOPT,6,10,2 !contact stiffness
  
  k, 0 , 0.0 , 3.0 , 0 !1
  
  k, 0 , 20.0 , 3.0 , 0 !2
  
  k, 0 , 20.0 , 7.0 , 0 !3
  
  k, 0 , 0.0 , 7.0 , 0 !4
  
  k, 0 , 0.0 , 20.0, 0 !5
  
  k, 0 , 20.0 , 20.0, 0 !6
  
  k, 0 , 0.0 , 0 , 0 !7
  
  k, 0 , 20.0 , 0 , 0 !8
  
  !!!!!!!
  
  !SHAFT!
  
  !!!!!!!
  
  LSTR , 1 , 2 !1
  
  LSTR , 2 , 3 !2
  
  LSTR , 3 , 4 !3
  
  LSTR , 4 , 1 !4
  
  /PNUM, LINE, 1
  
  LPLOT, ALL
  
  !CREATE AREA FROM ALL THE LINES
  
  !ASEL.ALL,
  
  AL,ALL,
  
  ASEL,ALL,,,
  
  CM,SHAFT,AREA
  
  !!!!!!!!
  
  !MAGNET!
  
  !!!!!!!!
  
  LSTR , 3 , 4 !3
  
  LSTR , 4 , 5 !5
  
  LSTR , 5 , 6 !6
  
  LSTR , 6 , 3 !7
  
  AL,3,5,6,7
  
  ASEL,S,AREA,,2,,,
  
  CM,MAGNET,AREA
  
  !!!!!!!!!!!!
  
  !2D MESHING!
  
  !!!!!!!!!!!!
  
  ASEL,ALL,
  
  ESIZE,1,0, !ELEMENT SIZE SPECIFICATION = 1 mm
  
  CMSEL,S,SHAFT,,
  
  type,1
  
  MAT,1
  
  AMESH,SHAFT
  
  ESLA,S
  
  CM,E_SHAFT,ELEM
  
  CMSEL,S,MAGNET,,
  
  type,2
  
  MAT,2
  
  AMESH,MAGNET
  
  ESLA,S
  
  CM,E_MAGNET,ELEM
  
  !!!!!!!!!!!!
  
  !3D MESHING!
  
  !!!!!!!!!!!!
  
  ET, 7,185 !SHAFT
  
  ET, 8,185 !MAGNET
  
  !meshing one set of magnets
  
  CMSEL,S,MAGNET,AREA
  
  esla,s,1
  
  type,8
  
  EXTOPT,ESIZE,10,0,
  
  VROTAT,all, , , , , ,7,8,180,,
  
  CM,MAGNET_E,ELEM
  
  CMSEL,S,SHAFT,AREA
  
  ESLA,S,1
  
  TYPE,7
  
  EXTOPT,ESIZE,10,0,
  
  VROTAT,ALL, , , , , ,7,8,180,,
  
  CM,SHAFT_E,ELEM
  
  !removing 2D elements
  
  CMSEL,S,SHAFT,AREA
  
  CMSEL,A,MAGNET,AREA
  
  ACLEAR,ALL,,
  
  ASEL,S,TYPE,,1,4,1
  
  ACLEAR,ALL,,
  
  !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
  
  !!!!!!!!!!!!!!!!!!!!
  
  !SPECIFYING CONTACT!
  
  !!!!!!!!!!!!!!!!!!!!
  
  LOCAL, 12, 1, 0, 0, 0, 0, 0, 90, ,
  
  CSYS,12 !activate cylindrical cordinate system
  
  !!!!!!!!!!!!!!!!!!!!!!!!!!!!
  
  !NAME SELECTION FOR CONTACT!
  
  !!!!!!!!!!!!!!!!!!!!!!!!!!!!
  
  !!!!!!!!!!!!!!
  
  !SHAFT-MAGNET!
  
  !!!!!!!!!!!!!!
  
  CMSEL,S,SHAFT_E,ELEM !select SHAFT elements
  
  nsle,s,ALL,1 !select node of the selected elements
  
  nsel,r,loc,x,7-0.01,7+0.01
  
  cm,S-M,node
  
  CMSEL,S,MAGNET_E,ELEM !select SHAFT elements
  
  nsle,s,ALL,1 !select node of the selected elements
  
  nsel,r,loc,x,7-0.01,7+0.01
  
  cm,M-S,node
  
  !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
  
  !!!!!!!!!!!!!!!!!!!!!!!!!!!
  
  !DEFINE CONTACT PROPERTIES!
  
  !!!!!!!!!!!!!!!!!!!!!!!!!!!
  
  MP,MU,1,0.1 !friction coefficient 0.1
  
  MAT,1
  
  !!!!!!!!!!!!!!
  
  !SHAFT-MAGNET!
  
  !!!!!!!!!!!!!!
  
  R,3,,,1.0,0.1,0,
  
  RMORE,,,1.0E20,0.01,1.0,
  
  REAL,3
  
  ET,14,170
  
  ET,15,174
  
  KEYOPT,15,9,3 !initial penetration effect
  
  KEYOPT,15,10,2 !contact stiffness
  
  ! Generate the target surface
  
  NSEL,S,,,S-M
  
  TYPE,14
  
  ESLN,S,0
  
  ESURF
  
  alls
  
  ! Generate the contact surface
  
  NSEL,S,,,M-S
  
  TYPE,15
  
  ESLN,S,0
  
  ESURF
  
  ALLSEL
  
  !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
  
  !!!!!!!!!!!!!!!!!!
  
  !DEFINE MATERIALS!
  
  !!!!!!!!!!!!!!!!!!
  
  CMSEL,S,SHAFT_E,ELEM
  
  EMODIF,all,MAT,1,
  
  CMSEL,S,MAGNET_E,ELEM
  
  EMODIF,all,MAT,2,
  
  !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
  
  !!!!!!!!!!!!!!!!!!!!!!!!!!!!
  
  !DEFINE BOUNDARY CONDITIONS!
  
  !!!!!!!!!!!!!!!!!!!!!!!!!!!!
  
  CSYS,0
  
  /solu
  
  alls
  
  nsel,s,loc,z,0
  
  DSYM,SYMM,X,0
  
  nsel,s,loc,x,0
  
  D, ALL, UX, 0,
  
  /solu
  
  NLGEOM,ON
  
  Time step 1
  
  TIME,1
  
  NSUBST,5 !define no. substeps
  
  allsel,all,
  
  BFA,ALL,TEMP,22
  
  SOLVE
- September 26, 2019 at 4:31 pm
  
  Rashi
  Subscriber
  
  I found an error and fixed it.
  
  The symmetry was defined in the wrong direction, so I fixed it as shown below.
  
  DSYM,SYMM,X,0 > DSYM,SYMM,Z,0
  
  But I still get results which are not correct.
- September 27, 2019 at 6:25 pm
  
  Rashi
  Subscriber
  
  Since defining interference fit in contact did not work I specified the interference in the geometry. Then I was able to get satisfactory results. Now I need to do the following,
  
  In WB we can specify a remote point to a set of nodes and specify the DOF to the remote point. How can I do the same in APDL? Is there a way to couple a keypoint and set of nodes?
  
  Thanks