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contact slip analysis

Sid_22073

Hello,

I want to find the torque required for the slip of the interference fit.

Could someone help me how can I do it.

If Could you please provide me any short sample opristruct deck (.fem file) or explain detail will help me.

I saw some of the posts earlier, but could not understand fully.

Thanks and I appriciate your help in advance !!

THanks for the help.

Looking forward for your reply.

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English

OptiStruct

v2022.1

Accepted answers

Adriano_Koga

Hello,

I have run 2 cases with SLIDING and with friction 0.12 between the pairs.

Please see the results below of the reaction moments about X axis.

The curves are pretty straight, I would rather expect a quadratic curve i.e increase in torque and after some time the torque decreases

Is my problem setup correct ?

Please note I applied SPCD of 6.28319 radian ie 360 degrees

can somebody help to resolve this if not correct ?

I did this small model here.

I got a decrease in the torque after some rotation.

I have 2 loadcases:

- press-fit

- rotation continuing from LC1

on the right corner in the bottom you will see torque x rotation

interference_fit_torque.fem

All comments

Adriano_Koga

could you add a few more details on what are you trying to accomploish, and maybe add some pictures?

If you want one part to be iserted into another, you will need a LGDISP contact with Continuous or Finite Sliding at least.

But with so few details it is hard to give you more insights.

Sid_22073

The pin (middle part) is assembled by an interference fit.

I want to now check how much torque this pin can withstand before slipping. For this want to apply torque at both ends of pin along the axis and somehow get the reaction forces and plot this in graph. I would like to see a no-linear curve ( timestep vs reaction force)

Please check the following .fem file and let me know if run correct.

First subcase is for contact

2nd subcase is for contact + moment

$$ optistruct
$
CONTF(H3D,PCONT) = YES
CSTRESS(H3D,ALL,NDIV=1) = ALL
DISPLACEMENT(H3D) = ALL
GPSTRESS(H3D) = ALL
SPCFORCE(H3D) = 5
STRESS(H3D) = YES
$$------------------------------------------------------------------------------$
$$ Case Control Cards $
$$------------------------------------------------------------------------------$
$
$HMNAME LOADSTEP 1"loadstep1" 9
$
SUBCASE 1
LABEL loadstep1
ANALYSIS NLSTAT
SPC = 1
NLPARM = 1
$
$HMNAME LOADSTEP 2"loadstep2" 9
$
SUBCASE 2
LABEL loadstep2
ANALYSIS NLSTAT
CNTNLSUB YES
SPC = 1
LOAD = 9
NLPARM = 1
NLOUT = 4
$$--------------------------------------------------------------
$$ HYPERMESH TAGS
$$--------------------------------------------------------------
$$BEGIN TAGS
$$END TAGS
$
BEGIN BULK
$$
$$ Stacking Information for Ply-Based Composite Definition
$$
$
$HMSET 5 1 "set1" 18
$HMSETTYPE 5 "non-ordered" 18
SET 5 GRID LIST
+ 2158833 2158834

...

$$$$ Contact definition

$HMNAME GROUP 1"CSurf_pin_CSurf_gear_fuelpumpside" "CONTACT"
$HWCOLOR GROUP 1 48
$$
$$ CONTACT Data
$$
CONTACT 1 SLIDE 1 2 -0.037
+ CONSLI
$
$$
$HMNAME GROUP 2"CSurf_Gear_outputside_CSurf_pin_1" "CONTACT"
$HWCOLOR GROUP 2 49
CONTACT 2 SLIDE 3 4 -0.037
+ CONSLI
$

$$
$$ Nonlinear Parameters
$$
$
$HMNAME LOADSTEPINPUT 1"nlparrm"
NLPARM 1 10 0.0 25
$
$$
$$ Output Parameters
$$
$
$HMNAME LOADSTEPINPUT 4"loadstepinput4"
NLOUT 4NINT 10

$$ Global SPC Data

SPC 1 212226 123456 0.0
SPC 1 212227 123456 0.0

$$ Also SPC Data ends of Pin ( Blue part)

SPC 1 2158834 123456 0.0
SPC 1 2158833 123456 0.0
$$
$$ SPCD Data
$$
SPCD 9 2158834 4 6.28319
SPCD 9 2158833 4 6.28319
ENDDATA

Sid_22073

Hello,

I have run 2 cases with SLIDING and with friction 0.12 between the pairs.

Please see the results below of the reaction moments about X axis.

The curves are pretty straight, I would rather expect a quadratic curve i.e increase in torque and after some time the torque decreases

Is my problem setup correct ?

Please note I applied SPCD of 6.28319 radian ie 360 degrees

can somebody help to resolve this if not correct ?

Adriano_Koga

Hello,

I have run 2 cases with SLIDING and with friction 0.12 between the pairs.

Please see the results below of the reaction moments about X axis.

The curves are pretty straight, I would rather expect a quadratic curve i.e increase in torque and after some time the torque decreases

Is my problem setup correct ?

Please note I applied SPCD of 6.28319 radian ie 360 degrees

can somebody help to resolve this if not correct ?

I did this small model here.

I got a decrease in the torque after some rotation.

I have 2 loadcases:

- press-fit

- rotation continuing from LC1

on the right corner in the bottom you will see torque x rotation

interference_fit_torque.fem

Sid_22073

Hi,

Thanks for the answer.

Is the SPCD i.e enforced rotation given to both ends of the shaft ?

Did you use friction ?

If possible Can you please share the model ?

Kind regards,

SId

Adriano_Koga

Hi,

Thanks for the answer.

Is the SPCD i.e enforced rotation given to both ends of the shaft ?

Did you use friction ?

If possible Can you please share the model ?

Kind regards,

SId

the model was there in my reply.

I've used SPC directly to impose rotation to one end only, attached to the RBE2.

I've used friction, otherwise there would be no decrease in torque, right?

Adriano_Koga

the model was there in my reply.

I've used SPC directly to impose rotation to one end only, attached to the RBE2.

I've used friction, otherwise there would be no decrease in torque, right?

i would add CONTF output in order to check the change in contact status, from stick to slip, when slippage starts to occur.

Sid_22073

Thank you very much !!

MaxvS

Hi guys, first of all thank you very much, with your help I was able to set up my contact slip case. But I am not sure if my result in the spc moment is correct. Similar to your results @Adriano_Koga
My moment is 1 - 10^7 Nmm, which is very high in my opinion?

I have a 50 mm shaft with a shaft ring of 49.78 mm and a diameter of 70 mm. There is contact between the two components with a friction coefficient of 0.15.