Design of a motorcycle swing arm/suspension systemAshley ThorneBsc (Hons) applied technology project.Staffordshire uniiversity_2013

Project Aims and objectives

• To attain and apply a understanding of the working principles of motorcycle suspension systems.

• To develop an applicable solution using CAD software (Creo parametric 2.0)

• To apply Material/joining selection in accord with FEA(Creo simulate 2.0) studies to evaluate and develop the structural profile of the system.

• To implement multi-body dynamics studies(Msc Adams) to simulate vehicle operation and obtain data relating to system performance .

Project methodology Re-design

Synthesis of results

data Design validation and virtual testing

Concept generation

Problem definition/motivation

Research

Design concepts

FEA Loads and constraints

Pivot one

Fixed

Pivot two

Fixed

Pivot three

Loaded

Material selection      

Function: Support bending and torsion loads

Constraints: Dimensions of length and width Must accommodate packaging requirements.

Objectives: Minimise mass: Optimise lateral and torsional stiffness

Free variables: Cross sectional area, choice of material.

Additional consideration Joinability/ fabrication

Selected material :Aluminium, 6061, wrought, T6

FEA results and implicationsLongitudinal loading Torsional loading

Max loading case approximated by considering vehicle and rider masses hitting a bump while the entire mass is balanced on the rear wheel (wheelie).

Max loading case calculated by calculating leverage produced by the height of the wheel and tyre in addition to the width of the swing arm as a product of the maximum theoretical tyre force generated.

MBD Results and implicationsThe final model was

comprised of

• 6 Degrees of freedom• 14 Moving Parts (not

including ground)• 2 Cylindrical Joints• 1 Planar Joints• 6 Revolute Joints• 2 Translational Joints• 5 Fixed Joints

The multibody dynamics analysis took the form of the following simulations•Drop tests

•Bump tests •Effects of bump frequency on vertical displacement of the wheel and frame

MBD Results and implicationsBelow is shown the results of a bump frequency simulation, imitating what is know in industry as a two poster rig and is used to simulate many operating condition relating to the suspension system.

Synthesis

• Is the design Feasible ?

• Has the systems performance been tested sufficiently to justify application?

• Are results valid?

• Identify areas where simulation/analysis procedure can be improved!

Conclusion and recommendations

• Increase in the accuracy of the FEA model will produce more reliable results.

•Increase in the complexity of the multibody model would allow for a greater range of operating conditions to be observed

•Virtual results should be backed up by real world test data

Acknowledgements

• Many thanks to all who contributed to the completion of this project and gave assistance throughout the course of study.

Professor David Cheshire Chris smout Alex Heaton

Staffordshire university

Thanks for listening !

Any questions?