Interference Fit
Interference Fit
(OP)
Hello Friends,
I wanted to know wat values do i have to take for stiffness factor and friction in contact wizard to get my force required to cause the pressfit between a slug and receiver(fixed), I am trying to verify empirically and compare with ansys results. Could anyone explain all steps for doin press fit analysis. I used contact tutorial in ansys, but of no use.Please help me with ur tips.
Thank you.
cheers
I wanted to know wat values do i have to take for stiffness factor and friction in contact wizard to get my force required to cause the pressfit between a slug and receiver(fixed), I am trying to verify empirically and compare with ansys results. Could anyone explain all steps for doin press fit analysis. I used contact tutorial in ansys, but of no use.Please help me with ur tips.
Thank you.
cheers





RE: Interference Fit
You already know the interference materials. You can find out from the internet search engine on the friction coefficient for some materials. You may base on experience the similarities of other materials. Else, you need to measure it from experiment.
The CAD models, I presume are already modeled using the worst case interference, so you can just use a simple linear isotropic material model, using only the Young's modulus, Poisson's ratio, density not required but no harm adding.
Constraining is important so check your pushing direction be free and which is fix or moving and any other constraints which may be necessary. If analysis cannot complete, then begin by constraining secondary conditions first, then running by releasing the constraints based on priority.
All the best.
RE: Interference Fit
Thank you
cheers
harid
RE: Interference Fit
If I may ask. Thanks.
RE: Interference Fit
Thank you.
cheers
harid
RE: Interference Fit
I am wondering if it could be the interference you are using. So what is the total interference you have modeled for your interfering parts?
RE: Interference Fit
After the analysis, I obtained the contact stress between the interfering parts.
I used the highest stress value obtained to calculate the minimum corresponding force to overcome this frictional contact stress.
With the maximum area of interference contact which I obtained from the CAD software for the parts, I determined the maximum force required, based on the formula of stress equals to force divided by area.
Hopes this works for you too.
RE: Interference Fit
/PREP7
K,1,2.05/2,0,0,
K,2,12.5/2,0,0,
K,3,12.5/2,9,0,
K,4,6.15/2,9,0,
K,5,6.15/2,6,0,
K,6,2.05/2,6,0,
LSTR, 1, 2
LSTR, 2, 3
LSTR, 3, 4
LSTR, 4, 5
LSTR, 5, 6
LSTR, 6, 1
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FITEM,2,1
FITEM,2,2
FITEM,2,3
FITEM,2,4
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K,7,2.05/2,9.5,0,
K,8,6.17/2,9.5,0,
K,9,6.17/2,11.9,0,
K,10,12.5/2,11.9,0,
K,11,12.5/2,17.5,0,
K,12,2.05/2,17.5,0,
LSTR, 7, 8
LSTR, 8, 9
LSTR, 9, 10
LSTR, 10, 11
LSTR, 11, 12
LSTR, 12, 7
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FITEM,2,7
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AMESH,_Y1
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CMDELE,_Y2
!*
!*
!*
!*
!*
/COM, CONTACT PAIR CREATION - START
CM,_NODECM,NODE
CM,_ELEMCM,ELEM
CM,_LINECM,LINE
CM,_AREACM,AREA
/GSAV,cwz,gsav,,temp
MP,MU,1,0.3
MAT,1
MP,EMIS,1,7.88860905221e-031
R,3
REAL,3
ET,2,169
ET,3,172
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RMORE,0.0,0,1.0,,1.0,0.5
RMORE,0,0.5,1.0,0.0,
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KEYOPT,3,9,0
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KEYOPT,3,12,0
! Generate the target surface
LSEL,S,,,4
CM,_TARGET,LINE
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ESURF,ALL
CMSEL,S,_ELEMCM
! Generate the contact surface
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CMSEL,S,_LINECM
CMDEL,_LINECM
CMSEL,S,_AREACM
CMDEL,_AREACM
/GRES,cwz,gsav
CMDEL,_TARGET
CMDEL,_CONTACT
/COM, CONTACT PAIR CREATION - END
APLOT
FINISH
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FITEM,2,1
!*
/GO
DL,P51X, ,ALL,0
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/GO
DL,P51X, ,UX,0
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!*
/GO
DL,P51X, ,UY,-2.9
!*
ANTYPE,0
ANTYPE,0
NLGEOM,1
NSUBST,10,1000,10
OUTRES,ERASE
OUTRES,ALL,-10
TIME,2.9
FLST,3,1,1
FITEM,3,3514
MONITOR,VAR2,P51X,UY
FLST,3,1,1
FITEM,3,3514
MONITOR,VAR3,P51X,FY
CHEERS
Harid
RE: Interference Fit
I have went through your input.
I am not sure, but why not you model your material property to the stress strain data.
The stresses with strain might be lower than your current analysis.
The material I used for my analysis followed the stress strain as provided by vendor.
RE: Interference Fit
Thanks again
Harid
RE: Interference Fit
Thanks again
Harid
RE: Interference Fit
Values from the instron machine with control test pieces should be good enough.
However, better if material supplier has it.
All the best.
=======================================================
/NOP
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TB,MISO,_MATL , 1, 13
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TBPT,, 6.000000000E-02, 5.0000000
TBPT,, 7.000000000E-02, 6.0000000
TBPT,, 8.000000000E-02, 10.000000
TBPT,, 9.000000000E-02, 30.000000
TBPT,, 10.00000000E-02, 45.000000
TBPT,, 11.00000000E-02, 55.000000
TBPT,, 12.00000000E-02, 60.000000
TBPT,, 13.00000000E-02, 62.500000
/GO
RE: Interference Fit
thanks
harid