FEA boundary conditions

Dear AnyBody:

After we import internal forces (i.e., joint, muscle forces etc.) as FEA’s boundary conditions, how do we know the forces are applied from the correct locations?

As shown in the pictures, on the left the muscle/joint forces were superimposed on the tibia; on the right what you see is the mesh of the same tibia imported to abaqus, with BC shown. When I look closely at those BCs, some of them are fairly far away from the bone. I am a little baffled because since all forces in AnyBody including the origin and the direction of the forces were imported into ABAQUS exactly the same way as the tibia (mesh), if the origins of the forces are correct in AnyBody model, they should be correct in the FE model.

Secondly, can you give me more detailed instruction about creating “spider web” type of constraints to the joint articulated surface to remove stress concentration?

Thank you very much!

-Phoebe

Hi Phoebe,

those “outliers” are typically some via points representing muscles paths and, in case of tibia, there might be muscles connected to the fibula.

Spider web - it should effectively represent the muscle attachment area or a part of it that is being pulled by the muscle. For the joints you might want to select an assumed area of contact. I guess this is the best I could recommend.

Kind regards,
Pavel