Session: MSNDC-02-01: Flexible Multibody Dynamics

Paper Number: 89945

89945 - Modeling of the Weave and Wobble Eigenmodes of Motorcycles Using Flexible Multibody Simulation 

Weave and wobble are well known eigenmodes of motorcycles and have been studied by several authors because of their importance to the overall stability and safety of motorcycles. Studies have highlighted the importance of structural flexibility on the stability of these eigenmodes. A common approach in multibody simulation for modeling the flexibility is the lumped stiffness method. It is advantageous for its limited modeling effort and its small impact on computational time. However, it was never demonstrated if this approach leads to sufficient accuracy when simulating the weave and wobble eigenmodes. After a literature review on the methods for modeling the flexibility of structural components, the present work tackles this problem by modeling the structural components of a motorcycle with the flexible multibody approach. The most relevant structural components for the stability of weave and wobble are identified. A comparison with the lumped stiffness approach is also proposed. In particular, considerations about the tests needed for the identification of the lumped parameters are made, which highlight the main issues in the modeling with lumped stiffnesses. Moreover, some implementation details concerning models with flexible bodies are discussed. This includes the analysis of two different methods for model order reduction and the comparison of two formalisms for the implementation of the flexible multibody approach.

Presenting Author: Francesco Passigato Technical University of Munich, School of Engineering and Design, Chair of Automotive Technology

Presenting Author Biography: My academic career started in Trento, Italy, where I studied industrial engineering in my bachelor. After that I applied for the double degree program between the universities of Trento and Munich. Thanks to this program, I had the possibility to specialize in mechatronic and automotive engineering.<br/>I started my PhD in march 2020 at the Technical University of Munich. My research area is the simulation of motorcycle dynamics, with particular interest in the analysis of the weave and wobble eigenmodes. Currently, I am analyzing the effect of the flexibility of structural components on these eigenmodes. Part of my research program is also to develop a control system to improve the stability of weave and wobble.

Authors:

Francesco Passigato Technical University of Munich, School of Engineering and Design, Chair of Automotive Technology
Achim Gordner BMW Group
Frank Diermeyer Technical University of Munich, School of Engineering and Design, Chair of Automotive Technology