MPC contact regions / boundary conditions conflict

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  • Last Post 05 September 2018
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Mohankumar posted this 04 September 2018

Hello,

I want to measure the rotation of vertebra. Here is what I did:

(1) Fixed lower surface of the lower body. Applied moment (10,000 N.mm) on top surface of the top body in Z axis. (2) Checked whether the contact regions between disc, top and bottom body are intact. (3) Solver type: Direct, Contact type: Bonded. (4) Selected Remote Point and Flexible Rotation Probe (Z axis).

After running the simulation, results look unrealistic and got warning message.

Top body rotated beyond the obstruction provided by lower body. Looking as if it penetrated into the lower body. Hence it is measured as 4.9971 degrees. Which is not acceptable. Normal range is 1.5 to 2.5 degrees only. Warning message: "One or more MPC contact regions or remote BC may have conflicts with applied BC"

How to solve this?

 

Thanks in advance.

Contact ResultDetails of Contact PointDetails of Contact Point 2Result

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peteroznewman posted this 04 September 2018

Hello Mohankumar,

I assume between the lower body and the top body, which are bones, is the disk body. I also assume that the Bonded contact shown is each bone to the disk.

One way to prevent the penetration between the bones that you drew the rectangle around is to add Frictional contact between those faces. Bodies can pass through each other by default. You have to add contact when you don't want that to happen.

Regards,

Peter

 

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SandeepMedikonda posted this 04 September 2018

Hi Mohankumar,

  Please see some of the guidelines listed in this section of the manual that talks about how to deal with penetration problems.

P.S: Please see how to access ANSYS Help here.

Regards,

Sandeep

Mohankumar posted this 05 September 2018

Thank you Mr. Peter. Will try your suggestion.

Mohankumar posted this 05 September 2018

Mr. Sandeep,

 

We have Ansys 18 only and moreover, I couldn't able to log in into Ansys Help. But I have an account in Ansys Customer Portal. Is their any other way to see the guidelines which you mentioned?

 

Regards.

 

 

peteroznewman posted this 05 September 2018

 Hi Mohankumar,

You can open ANSYS Help if you have the program open by using the Help Menu. One of the links Sandeep is pointing to can be found in the ANSYS 18 system at this location:

You get to that by navigating the menu tree on the left side of the Help window.

Regards,

Peter

SandeepMedikonda posted this 05 September 2018

Mohan,

  Please see if this workaround suggested by peter helps? 

Regards,

Sandeep

peteroznewman posted this 05 September 2018

 Sandeep,

That workaround only works if the computer has ANSYS Student 19.1 installed.

Regards,

Peter

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