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What is MbDFEM?

MbDFEM is the combination of Multibody Dynamics (MbD) and Finite Element Method (FEM). It is the combination of Motion Simulation and Stress-Strain Calculation using true physics. It simulates the complete large motion of a machine and reveals the stress-strain conditions of every part of the machine throughout the motion. Together with Computer Aided Design, it enhances the invention and improvement of mechanical machines or mechanisms at any level of complexity or scale. It reduces the risk of failure and overdesign when the actual machine is built. Our current combination of CAD, MbD and FEM consists of:

  • FreeCAD: CAD modeling and pre/post-processor.
  • FreeCADMbD: Our custom MbD solver.
  • MBDyn: A full-featured MbD solver.
  • Calculix: A widely used FEM solver.

which are all open source software. MbDFEM is a workbench in FreeCAD and is a work in progress. The results below show our progress. We look forward to input on desired features and suggestions for models to simulate. The simulation results will be made public. Proprietary models can be simulated for a modest fee.

What are our capabilities?

Fully scriptable and automatable workflow:

Go beyond the GUI. The complete workflow—from assembly solving to FEM analysis—can be seamlessly automated using logical, human-readable input files:

  • Attach markers to the geometry and connect them using joints.
  • Use the same joints for both assembly solving and MbD/FEM simulations.
  • Fully control the meshing parameters from the input file, using a clear syntax.
  • Full control over the visualization: Set vector scales. Control the density of vector fields. Configure the camera position and rotation. Attach the camera to any point of a part, a joint, etc.
  • A fully-integrated CAD-MbD-FEM workflow:

  • It is not necessary to manually export-import geometry from CAD into MbD, identify critical loading frames in MbD, and apply FEM loads and inertia relief only for those critical loads. Our software automates the whole process, for the complete range of motion.
  • Solving the FEM for the whole range of motion provides a clear insight into the stresses, regardless of the ability to identify critical loading cases, which may not always coincide with the maximum MbD forces/torques.
  • CAD is the master model. If the CAD changes, the assembly, MbD and FEM are automatically updated to show the new forces, torques and stresses.
  • FEM results without the computational costs of a dynamic simulation:

    Our quasi-static approach provides reliable FEM results for the entire range of motion of the mechanism, in a fraction of the computational time required by a dynamic simulation.

    Explore more: Practical Applications.

    Why simulate with us?

    Reliability:

    Our simulations are grounded in rigorous real-world physics formulations that fully respect the laws of dynamics. The software has been carefully developed to remain faithful to these formulations, ensuring physically accurate and therefore reliable results, and giving engineers the confidence to apply these results in the design and optimization of mechanisms.

    Outstanding Visualization:

    Our custom post-processor brings every detail of your simulation to life. Visualize joint forces, torques, and part velocities and accelerations, alongside vector fields such as FEM loads, body weight and d'Alembert forces, and more. Stresses and strains are seamlessly integrated into clear and intuitive animations, giving you unmatched insight into the problem, and the confidence to trust the results.