Learning Forum

[OmidNazeri1997]

Hi everyone.

I have some issues simulating the human knee joint behavior. I had asked some questions about them before, but i got no response.

Here is the link to the main topic page:

/forum/forums/topic/knee-joint-simulation/

I would appreciate if anyone could help me!?

[Saumadeep Choudhury]

 

Hi,

Referring to the question thread that you posted, I can see you have used frictionless support, where frictionless contact is specified.
One thing to note here is that Frictionless Support is not equivalent to Frictionless Contact. To know more about frictionless support refer to this link:
Frictionless Support (ansys.com)

Meanwhile, can you share images showing the faces where you used frictionless support for more clarity on the boundary conditions applied by you?
Also, are you using the Ansys Student version to carry out this analysis?

Regards,
Saumadeep

 

[OmidNazeri1997]

Hi Saumadeep. Thanks. Yes I'm using ANSYS 2019 R3. Is there any difference between student and academic version??

I applied 3 frictionless supports to the model:

[OmidNazeri1997]

Hi Saumadeep. Which version of the ANSYS do you recommend? I only have access to the student versions of this software. I can't find any free academic version.

[Saumadeep Choudhury]

Hi,

It's always recommended to use the latest version of Ansys. In this case 2022 R2 (Download Ansys Student | Workbench-based Simulation Tools).

Only the Student Version of Ansys is available for free. The Student Version has some problem size limits, mentioned below:

Problem size limits on Student Version:

           Structural Physics: 128K nodes/elements
           Fluid physics: 512K cells/nodes
           Electromagnetics: N/A

[OmidNazeri1997]

Hi Saumadeep, thank you so much for your help?

[Saumadeep Choudhury]

 

For the problem mentioned above, The usage of frictional support here won’t help and would only make the system over-constraint leading to much higher stresses than actually what it should be. Can you try using different boundary conditions here, like using frictionless contact between the bones?

 

[OmidNazeri1997]

Sure, i will try your advice.

[OmidNazeri1997]

Dear Saumadeep.

Thank you for your help. As you mentioned, i removed the frictionless supports and the results are now exactly similar in terms of order.

I also used the frictionless contacts between the bones. But, it won't change the results. As you can see, these bones are not directly connected to each other. So, using contact between them seems unnecessry.

I get warning messages, but the solution ends up successfully.?

[Saumadeep Choudhury]

Hi OmidNazeri,

Glad it worked out. Thanks for informing me.