Real-Time Simulation of Flexible Multibody Systems in Vehicle Dynamics


Real-time simulation models are commonly used in vehicle technology. Driving simulators, ECU test benches and control algorithms rely widely on these models. In most cases the vehicle is modeled as a rigid multibody system, neglecting the elastic deformation of the bodies. However, more complex body shapes and lightweight designs require to include these deformations in the simulation models. This research is focussing on representing elastic vehicle deformations in flexible multibody systems using model order reduction (MOR) technologies. The objective is to gain real-time capable elastic vehicle models by efficient modeling and programming.

Tool Chain

The flexible multibody system is based on a nonlinear two-track model, with or without suspension kinematics. The tire behavior is represented by the tire model MF-Tire, the road surface is modeled with the OpenCRG environment. Other models can be used as required.

To consider the structural flexibility within the model, the CAD-geometry of the bodies have to be meshed with a common finite element program like Abaqus or Ansys. Existing finite element models can be used as well. Since the number of degrees of freedom (DOF) of a complete finite element mesh massively exceeds the calculational power of current CPUs for real-time simulation, a linear model reduction is performed. Used reduction algorithms include modal reduction and Craig-Bampton methods.

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Various applications are possible, including control algorithms, real-time stress calculation, driver-in-the-loop simulations. A modular concept allows various applications, platform-independent components allow the operation on miscellaneous target systems.

Contact information

Dipl.-Ing. Alexander Schmitt

Prof. Dr.-Ing. Robert Seifried