Rethinking Motorcycle Suspension: Girder Suspension Stability and Dynamic Simulations

Vishvam
Vishvam
Altair Employee
edited December 18 in Altair Exchange

Rethinking Motorcycle Suspension: Challenges in Achieving Precision and Stability with Girder Suspension Configurations in Dynamic Simulations 

PREFACE 

The dynamics of motorcycle suspension systems, particularly unconventional designs like girder suspension, present unique challenges in optimizing ride stability and handling. Physical testing of these systems across different riding conditions can be costly and time-consuming. Multibody dynamics simulation provides an efficient solution to model and analyze the complex interactions between components. Using software such as Altair’s MotionSolve and MotionView engineers can simulate the behavior of girder suspension systems under various load conditions, enabling detailed evaluation and refinement of the design. Through these simulations, it becomes possible to enhance ride performance and ensure the suspension system operates effectively across diverse scenarios.

INTRODUCTION 

In the world of motorcycle engineering, suspension systems are at the heart of performance and rider control. While telescopic forks have long dominated the scene, the revival of girder suspension offers a fascinating alternative, combining historical innovation with modern engineering challenges. Unlike traditional systems, the girder suspension’s unique structure offers the potential for superior rigidity and improved handling—but unlocking these benefits requires a deep understanding of the complex dynamics at play.

The girder suspension’s unconventional geometry introduces intricate challenges in balancing load distribution, ensuring stability, and managing suspension kinematics. As with any critical component of a motorcycle, the stakes are high: the rider’s safety, comfort, and performance depend on the precise interaction of forces and movements throughout the system.

This article dives into the multibody dynamics simulation of a motorcycle fitted with a girder suspension, using Altair MotionView/MotionSolve to model and analyze the system’s behavior. Through simulation, we explore how the suspension responds to various forces and conditions, identifying potential issues and fine-tuning the design for optimal performance. Whether it’s navigating sharp turns or handling uneven terrain, this study aims to refine the girder suspension, pushing the boundaries of what’s possible in modern motorcycle dynamics.

SOFTWARE REQUIREMENTS

Altair MotionView (2023 or newer)

Altair MotionSolve (2023 or newer)

MODEL FILES

Girder_Suspension_Motorcycle.zip (See Attachments)

Understanding the Model Definition in MotionView

This model setup assumes a level of familiarity with Motionview/Motionsolve. A motion-ready model called Girder_Suspension_Motorcycle.mdl is available for reference in the attached zip file.

The simulation model focuses on the front suspension system of the motorcycle, featuring a girder suspension design. The girder suspension is connected to the frame through joints, simulating real-world mechanical linkages. While certain dynamic aspects, such as internal damping mechanisms or manufacturing tolerances, are not explicitly modeled, the simulation emphasizes the system’s response under operational conditions. The multibody simulation investigates how the forces during different types of events influence the stability, ride comfort, and handling characteristics, providing insights to refine the girder suspension's design for optimal performance.

MODEL SETUP

Bodies:

  • The model contains a Frame, Front Girder suspension unit, Rear mono suspension unit, swingarm, spindle and wheels with Autotires from Motionview.
  • The dummy rider is simply fixed to the frame to visualize and simulate the rider effects on the motorcycle.

Joints:

  • The following images show a clear architecture of parts included in front girder suspension.
image.png

  • The following joints combination is used to avoid any redundancy in the model
image.png

SIMULATION STEPS

  1. The model is now ready to run. Open the run dialog, select an output directory, select run offline, and hit run.
  2. After the simulation is completed, select results in the new window to view the animation.
  3. A report detailing many vehicle performance metrics can be generated by clicking report in MotionView and selecting the run.

RESULTS

After the completion of the analysis, the vehicle’s motion can be viewed in HyperView. Outputs including steering angles, driver inputs, vehicle accelerations, shock displacements, and more can be plotted using HyperGraph. Many of the key performance indicators are automatically graphed by creating a report in MotionView.

image2.gif
image3.gif

CONCLUSION

The multibody dynamics simulation of the girder suspension successfully highlights its potential for enhanced rigidity and handling in motorcycles. By leveraging Altair MotionView and MotionSolve, engineers can analyze and optimize suspension performance under diverse conditions, addressing stability and load distribution challenges. These simulations provide valuable insights to refine the girder suspension design, ensuring improved ride comfort and control. Ultimately, this approach demonstrates the power of simulation in advancing innovative motorcycle engineering solutions.

AUTHORS

Vishvam N, Solution Engineer - Systems Integration

Girder_Suspension_Motorcycle.zip

Tagged:

Categories