ABAQUS FEA fails without warnings in the message file

[ChristinaStudent]

I am running a FEA on a hip joint model where a femur is sitting in the hip socket but the range of motion in the socket is not restricted by ligaments. There's a contact surface between the femoral head and the socket and the model has multiple materials throughout but the actual surface contacts are the same material. I've worked through multiple errors and warning messages before this to try to make it work. First error occurred from improper boundary conditions being applied to a multi-material object. Once, this worked and I was no longer receiving an error for this I had to fix a warning message that was showing up regarding my bulk modulus, this resulted from me trying to model with hyper-elastic properties. I found that the only way to get it to work was to run the model as an elastic model but with my original hyper-elastic properties. Note, all of these previous models were run with a boundary condition/ displacement applied not a force. Finally, when I ran displacement tested model with a force instead, the analysis would fail with no additional warning messages the only thing it noted was that the solution was diverging and was unlikely to converge. Any guidance and help is very appreciated, thank you in advance.

[Mark Barkey]

Welcome to the forum--


It sounds to me like you probably have some rigid body motion in your model.  Something is likely taking off in space to infinity due to the applied force.  It would have been held in place in displacement control.

You should be able to check by loading what results you have into a post processor--either ABAQUS CAE itself or something like Hypermesh.

That is all I can think of based on your description.

take care,
MEB