MultiBodySystem Dynamics app for iPhone and iPad

Refresh your physics lessons about the dynamics of multi body systems and electric circuits. With this app, you can build models of real mechanisms, consisting of masses, springs, dampers, excitations and kinematics and so on. Just drag single translational or rotational components from the toolkit on a construction frame and define the parameters for linear and nonlinear elements in a very intuitive manner. Finally connecting these elements to each other with a few finger tips, the model is fully assembled and prepared for calculation.

Now its possible to combine the mechanic system with electric circuits to analyze hybrid systems. The electric circuits may consist of voltage or current sources, resistors, inductors, capacitors and transformers and, of course, of electric motors to combine the electric and mechanic part.

The analyses of the dynamic system is done in the frequency domain, where you can see dynamic behavior of the complete system if form of damped and undamped natural frequencies with the corresponding motions, forces, dynamic stiffnesses or dissipative energies of the mechanic part and current flows and voltage drops of the electronic parts. The results are visualized as Bode plots or Nyquist diagrams.

There are some more features to analyze and understand the dynamics of the system. Parameter variations as an offline or online process will help you to get an impression of the influence of each system parameter. Offline variations will solve the equations for a set of changing parameter values and visualize the results in form of a band of lines. Using the online variation you can change the values of parameters by sliders and the equations are solved instantaneously und the plot are updated right away. With this tools you get a deep understanding of the behavior of the system and the influence of each parameter.

Often it is interesting to compare two models with a different refinement. With an InApp you can do this with a finger tip. By duplicating a model it is possible to set parameter dependencies between the subsystems, so when you change the parameter in one subsystem the parameter of the other system also will be changed. Also the plots will be extended automatically to see a comparison of the models in one plot.

Special algorithms are implemented to deal with nonlinear dynamic elements. Besides the changing natural frequencies and damping behavior due to varying excitation amplitudes, the transfer function will change their shape and, as in real mechanisms, its a difference if frequency is growing continuously or if frequency is decreasing. Both effects can be analyzed by this app.

If you have any questions, troubles or suggestions, please use the contact formula in the app. This way its possible for me to give you a feedback.