FEM begins where the rigid body assumption breaks

FEM begins when a body can no longer be treated as perfectly rigid.

Multibody dynamics can predict motion, joint loads, and system-level behavior. But once deformation, stress concentration, stiffness, vibration modes, or material limits matter, the model needs a mesh and a structural solve.

The useful workflow is not MBSD or FEM. It is MBSD to find loads, then FEM to check whether the parts survive them.

Related:

• FEM and a Self-Optimizing design loop
• Launching a MBSD framework
• Compliant mechanisms and MultiBodySystemsDynamics dot com