Multibody Dynamics Training with MBDyn

• Introduction and use of the free multibody dynamics software MBDyn: http://www.mbdyn.org/.
• MBDyn is available as source code, to be compiled in the Linux environment: https://www.mbdyn.org/?Software_Download.
• Windows executables are occasionally made available; the currently recommended executable is available here: mbdyn-1.7.3-win32.zip (this archive contains the executable and two dll required for its execution, in case they are unavailable on the host system).

• A complete input manual is available at the same link of the source code (current release: 1.7.3)
• A short introduction is available at https://www.mbdyn.org/userfiles/documents/tutorials.pdf.
• Those interested in using or developing the software can contact the training staff or directly the mailing list mbdyn-users@mbdyn.org. Subscription is required prior to posting. Further details at the link MBDyn users.
• Training documentation:
  • MBDyn Overview.
  • MBDyn Primer (Class/homework: planar mechanism at end of primer).
  • MBDyn Simple Problems
• Cantilevered beam example: cantilever1 (from tutorials).
• Helicopter blade analysis:
  1. Model a single, rigid blade with flapping degree of freedom (e.g. bladeflap).
     
     
  2. Analyze the free response after excitation; use FFT to identify flap frequency in vacuo; compare with analytical result (square root of 1 + 3/2 ratio between offset and radius).
  3. Add root flap spring (deformable hinge joint) and size it to yield a total flap frequency of 110% rotor angular velocity.
  4. Model the rotor blade using beam elements (e.g. one or more three-node elements)
  5. Add a pitch bearing (revolute hinge joint) and a pitch control system (a pitch link modeled using a distance joint).
• Slider crank models