Problems with contact area and penetration depth

Hi, I am Dwan Lee.

I have problems with measuring contact area and penetration depth in the 6 DOF shoulder model.

The stiffness of articular cartilage was defined as 2.79e6 in this model.
After FDK procedure, the contact area and the penetration depth in the shoulder joint were measured as too large regardless of the humeral offset and the pressure module.

My questions are,

  1. How to control the contact area and the penetration in AnyBody model?
  2. How to calculate the contact area in AnyBody modeling system?

Thanks,

Best regards.

Dwan Lee

Hi @DWAN and welcome back to the forum!

Have you tried to use the code from the FDK tutorial lession 4 and 5?

Best regards,
Bjørn

1 Like

Hello @Bjorn

No, but I referred Sins model (Sins et al., J Biomech Eng., 2015). It was a good reference for my model.

There has no information about my trouble in the tutorial by the way.

Thanks,
Dwan Lee

Hi @DWAN

The tutorial shows how to do contact by means of stls, so you can control the stl and there by contact area. For the penetration the tutorial gives example of how to control the pressure module to change the penetration.

Best regards,
Bjørn

1 Like

Hello @Bjorn

Thank you for your quick response.

In the tutorial, changing sRel of STL can affect the penetration depth. However, It couldn't be solved by changing sRel in my model.
If the pressure module is too low like 5e-2, my model can run the FDK. But I am not sure 5e-2 is a reasonable value for validation.

Best regards,
Dwan Lee

Hi @DWAN

The exact value of the pressure module is not something I can give you, I would suggest to look at existing literature or setup a experiment to test it.

Best regards,
Bjørn

1 Like