Adding complex vector forces 1

[perzo84]

Hi

I have a problem with adding 3 kind of BC forces in one reference point. It's possible to do such thing because solver writing negative eigenvalue or solver pivot problem.
I need to add two boundary conditions describing rotation on this RP. Do you have any idea how I can do it ?

Ps I'm adding CAE with model.

 

[rstupplebeen]

Are all 6DOFs constrained allowing for a rigid body motion?

Rob Stupplebeen

 

[perzo84]

I need simulate hip joint in human leg and I need to combined three different human walk functions (components of the force vector) in the single RP. Also in human walk model I have to move a rigid body in three corners.

here is sample of my problem:

http://www.orthoload.com/main.php

http://jwi.charite.de/en/research/instrumented_implants/data_base/

http://bme.ntu.edu.tw/abc/17.3/17-3-7.pdf

 

[rstupplebeen]

I checked out your model and I believe that there are 2 errors. First, you need to constrain rotation in the Z direction for the RP. Second, you need to use your local coordinate system for your loading and displacements, assuming that was why you created it. Having all rotations for the initial step and then only X in step 1 in rotate_x is confusing for me and probably other people. I have made these changes in your CAE file and have the job submitted. I will post the file assuming that it runs once my current job finishes. I hope this helps.

Rob Stupplebeen

 

[rstupplebeen]

I ran your model with the suggested changes and it did not complete. I believe it is because you are defining large rotations and forces immediately in the first step. I would suggest a preloading step with ramping as the loading and displacement method. Have the values correspond to the initial point you have in your data sets.

FYI if you do a file save as your CAE file often reduces significantly in size. In this case over 10X

I hope this helps.

Rob Stupplebeen

 

[perzo84]

Thanks a lot. This is what I need.

perzo84