The Altair Bushing Model for Multibody Simulation

Bushings are commonly used as compliant connectors in automobiles. They are characterized by nonlinear stiffness and damping, which is usually described by a loss angle. In a dynamic loadcase, the actual stiffness and loss angle also depend on the frequency and amplitude of the deflection, but also on the preload in a specific event.

Altair has developed a Bushing Simulation Model that respects all of these dependencies. The Bushing Model can represent rubber or hydromount bushings and a combination of those with their typical behavior, such as gradually showing more of the hydromount behavior with increasing deflection amplitudes (decoupling). A LuGre friction model for spherical connectors suggests the use of the Bushing Model in place of ball joints as well. A "Serial Stiffness" model is included, so that the flexibility of components, which are modeled using rigid bodies themselves, can be accounted for in a computationally inexpensive way.

The Altair Bushing Model is Part of the Hyperworks Suite and comes with a Solver-Model, Preprocessing GUI and a tool to identify the parameters from physical test data. In addition to that, Altair Product Design has integrated the Bushing Model with Matlab/Simulink, Simpack and ADAMS/Car for BMW. This simplifies the model parameterization and comparison of simulation results in a multi-solver environment significantly.

 

The Author

Ingo Nolden
Senior Project Engineer
Altair Engineering