Hip joint translation

Hello
I am working on biomechanical analysis of the hip joint. I have patient data, who has a deformity of the femur and pelvis, which can lead to hip dislocation.
I changed the geometry considering the CT data. I also have data from the MOCAP system.

I read about the FDK function and tried to use it in my model. However, I wonder if this function is only used for joint implants. The tutorials I found use this function only for implant analysis.
Tell me, is it wrong to use the FDK function on my model (bone -bone)?

If I can't use this function (FDK) to analyze my model, please give me a hint how I can modify the model.
I want to unlock the hip joint and be able to simulate translation (in x,y,z directions) in the hip joint (between the head and the acetabulum). And then calculate value of these translations and the rection forces in the hip joint.

Thank you for your response.
Monika

Hi Monika,

There is nothing wrong in using FDK on bone-bone contact, i does not have to be on implants.

Since the contact forces are based on the surfaces shape, the quality of the bone surface becomes important so your joint surfaces specifically needs to be of good quality.

You could try to make a small test using your surfaces in this way:

  1. Attach one surface to a fixed frame
  2. Make a segment and attached the second surface to it
  3. Create a prismatic joint on the segment
  4. Create a surface contact between the two surfaces
  5. Add a motion driver, that forces the two surface into each other.
  6. Evaluate the resultant force of the motion driver

This will be a quick way to check the quality of the surfaces impact on the model, if you see "jagged" force output it may cause troubles for the FDK solver and convergence could be slow.

See also https://github.com/AnyBody/support/wiki/All-about-Force-Dependent-Kinematics#anyforcesurfacecontact

Best regards
Søren

Try to make a simple model with the two surfaces