SIMULATION STRESS AND FINITE ELEMENT ANALYSIS BASED OF

SUZUKI FXR 150cc MOTORCYCLE CHASSIS

MOHD KHAIRUDIN BIN YAHYA

A report submitted in partial fulfillment of the

requirements for the award of the degree of

Bachelor of Mechanical Engineering

Faculty of Mechanical Engineering

Universiti Malaysia Pahang

NOVEMBER 2007

ABSTRACT

Simulation stress and finite element analysis of Suzuki FXR 150cc

motorcycle chassis is the main focus of this project. This research was carried out to

investigate the most critical point or joining of a chassis part location of the vehicle

to enhance more comfort and safe ride. The information that has been used is based

on the previous study about the frame. The approximation measurement of the model

of Suzuki FXR 150cc motorcycle chassis had been done. The analysis is done either

by experimental or finite element analysis. The result from the analysis is an

approximation of the component failure. In the mean time, the software development

is improving in this few decades. Most of the new software makes the analysis and

designing easier to understand. This project aim to determine the location and stress

concentration of Suzuki FXR 150cc motorcycle chassis with the aim of frame as the

major data contribution. Solidworks and Algor software is used for determination of

stress concentration on the component and the system.

iv

ABSTRAK

Simulasi regangan dan analisis finite element ke atas kerangka motosikal

Suzuki FXR 150cc adalah focus utama projek mi. Kajian mi dikeluarkan untuk

menyisat titik atau sambungan paling kritikal ke atas lokasi casis motosikal tersebut

untuk mempertingkatkan keselesaan dan keselamatan penunggang. Makiumat yang

telab digunakan adalah berdasar kepada pengajian tentang kerangka motosikal

sebelum mi. Pengukuran penghampiran ke atas kerangka model motosikal Suzuki

FXR 150cc telah dilakukan. Analisis yang telah dibuat sama ada finite element

analisis atau melalui eksperimen. Selain itu, banyak komputer program boleh

didapati pada waktu sekarang mi. Kebanyakan komputer program yang terkini untuk

tujuan reka cipta dan analisis mudah difahami. Analisis yang akan dijalankan

bertujuan untuk mencari tumpuan regangan path casis motosikal Suzuki FXR 150cc

dengan menumpukan kepada kerangka sebagai penyumbang data terbesar. Program

Solidworks dan Algor digunakan untuk mencari tumpuan regangan pada komponen

tersebut.

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TABLE OF CONTENTS

CHAPTER TITLE PAGE

ACKNOWLEDGEMENT iii

ABSTRACT iv

ABSTRAK v

LIST OF TABLES ix

LIST OF FIGURES x

LIST OF SYMBOLS xii

LIST OF FORMULAS xiii

LIST OF ABBREVIATION xiv

LIST OF APPENDICES xv

1 INTRODUCTION

1.1 Background 1

1.2 Project Title 3

1.3 Objectives 3

1.4 Scopes 4

1.5 Problem Statements 4

1.6 Flow Chart 5

2 LITERATURE R1VIEW

2.1 Introduction 6

2.2 Fundamental of Chassis 7

2.3 Geometrical Definition 7

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2.3.1 Wheelbase 8

2.3.2 The wheel alignment and sprocket Alignment 8

2.3.3 Trail and offset 8

2.3.4 Ride height 9

2.3.5 Center of gravity 9

2.3.6 Engine fore and pivot position 10

2.4 Effects of Vibration Modes 11

2.4.1 Theories 11

2.4.2 Weave 11

2.4.3 Wobble 12

2.4.4 Capsize 13

2.5 The Handling of Motorcycle 14

2.5.1 Substitution of some parts 14

2.5.2 Soft damping 15

2.5.3 Throw anything away 16

2.6 Frame Type 17

2.7 Frame Material 19

2.8 Welding 20

2.8.1 Material Use To Weld 21

2.9 Frame Influence of StifThess 21

2.9.1 Tube size 22

2.9.2 Length 22

2.9.3 Use Gusset 25

2.9.4 Triangulate the structure 26

2.10 Aerodynamics 27

2.10.1 Drag Force 27

2.10.2 Lift Force 28

2.11 Software 28

2.11.1 CAD (Computer Aided Design) 29

2.11.2 CAE (Computer Aided Engineering) 30

2.11.3 Introduction to Solid Works 31

2.11.4 Introduction to Algor V16.1 32

METHODOLOGY

3.1 Methodology flow chart 34

3.2 Define problem 36 3.3 Literature review 36 3.4 Design 37

3.4.1 Design consideration 37

3.4.2 Design method 41

3.4.3 Analysis method 42

RESULTS AND DISCUSSION

4.1 Result 44 4.2 Center of gravity 44 4.3 Weight distribution 45 4.4 Stress analysis 45

4.4.1 Analysis of the frame at3ll9.58N 46

4.4.2 Analysis of the frame at 3021.48 N 48 4.4.3 Analysis of the frame at 4296.78 N 50

4.5 Discussion 52 4.6 Problem and errors 53

5

CONCLUSION AND RECOMMENDATION

5.1 Overall Conclusion 54

5.2 Recommendation 55

REFERENCES 56 Appendices A-K 59-70

vii'

3

4

LIST OF TABLES

TABLE NO. TITLEPAGE

4.1 - Loads given on the frame 46

4.2 Loads given on the frame 48

4.3 Loads given on the frame 50

4.4Comparison of maximum stress Von Mises for the frame part 52

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LIST OF FIGURES

FIGURE NO. TITLE PAGE

1.1 Final year project flow chart 5

2.1 Geometrical definition of motorcycle 10

2.2 Type of frame 19

2.3 Loaded in bending and the other in tension 23

2.4 A technique known as triangulate 23

2.5 Four sided structures 24

2.6 A gusset as supportive 24

2.7 Gussets 25

2.8 Flow chart of CAD approach in design 29

2.9 Design methodology in Solid Works 32

2.10 CADKEY option example where the file is exchange direct from CAD/CAB 33

2.11 Mechanical simulation model picture 33

3.1 Methodology flow chart 35

3.2 Frame remodel using CAD Solid Works 42

3.3 Frame analysis using CAB Algor 43

x

xl

4.1 Stress concentration on the frame 3119.58 N 46

4.2 Maximum stress concentration in red of colour 47

4.3 Stress concentration on the frame 3021.48 48

4.4 Maximum stress concentration in red of colour 49

4.5 Stress concentration on the frame for 4296.78 N 50

4.6 Maximum stress concentration in red of colour 51

LIST OF SYMBOLS

R Center of mass

M Total mass of the system

mi Mass

ri Position

Lever of the rear tire force with respect to the steering axis

Ir The moment of the inertia of the rear frame around the steering axis

k ?r Rear tire slip stiffness

a. Normal trail

If Moment of inertia of the front frame around the steering axis

k Xf Front tire slip stiffness

Summation

F Force

W Weight

N Newton

XII

LIST OF FORMULAS

FORMULA NO TITLE PAGE

2.1 Center of gravity

2.2 Center of gravity 10

2.3 Frequency of weave 12

2.4 Frequency of wobble 13

XII'

LIST OF ABBREVIATION

C G Center of gravity

CAE Computer Aided Engineering

CAD Computer Aided Design

xlv

xv

LIST OF APPENDICES

APPENDIX TITLE PAGE

A Calculation to find center of gravity 57

B Measurement data for overall part of chassis frame 58

C Location of center gravity 60

D Figure of Solid Works technical drawing 61

E Standard weight for human 63

F Shape deformation of chassis after certain given loads 64

G Gantt Chart 65-66

H Sketching of part and measurement 67

I

View of Suzuki FXl50cc 68

J Specification of Suzuki FX 150cc 69

K View of Suzuki FX 150cc motorcycle thune 70

CHAPTER 1

INTRODUCTION

1.1 Background

In recent years there has been an increased motorcycle sales momentum in

various parts of the world. In China alone, "Guang Cai Motorcycle Association of

Imports and Exports" estimates the two-wheeler sales for a typical month in year

2000 to be around 5.8 million, giving an increase of 13.72% from the same month in

the previous year. During this period the trend has been for people to shift towards

machines with higher engine capacities. The Ministry of Road Transport &

Highways, Government of India, gives the total number of registered two-wheelers

as on 31 March 2000 to be just less than 34 million compared with 4.57 million for

cars, while according to the Japan Automobile Manufacturers Association the total

number produced in Japan was in excess of 2 million for year 2002.

Motorcycles are typically used for commuting or for pleasure. Lighter

vehicles with smaller engines are usually cheaper than their heavier counterparts and

provide the primary means of transport in a lot of Asian countries. "Harley-

Davidson" type tourers are very popular in the United States while a wide variety of

Japanese exports come to Europe. Pleasure is mostly acquired from riding powerful

sports road bikes. Nowadays it have designs and engine performances that can easily

be compared with full racing machines only a decade old. It is also common for

police to use big powerful machines and often they have to ride them under difficult

circumstances at high speeds. Needless to say, a lot of investment nowadays goes

into motor racing and development of state-of the-art high technology machines.

2

A motorcycle (or motorbike) is a two-wheeled vehicle powered by an engine.

The wheels are in-line, and at higher speed the motorcycle remains upright and stable

by virtue of gyroscopic forces; at lower speeds continual readjustment of the steering

by the rider gives stability. The rider sits astride the vehicle on a seat, with hands on

a set of handlebars (either a single bar or or "clip-on"s which are used to steer the

motorcycle, in conjunction with the rider shifting their weight shift through their feet

which are supported on a set of"footpegs" or "pegs" which stick out from the frame.

Variations exist: some motorcycles are equipped with floorboards instead of

footpegs, and sidecars and other three-wheeled variations, commonly refened to as a

strike may also be found.

Several cases of serious accidents that involve no other road user have been

reported in the popular motorcycle press over the past decade and these are believed

to have been based on one or more of the above phenomena. Even though this type

of accident has been known for a long time, it has proven remarkably difficult to

obtain a complete understanding of the mechanisms involved. The main reasons for

this seem to be the following: Firstly, unlike aircraft, motorcycles do not possess

"black boxes" and therefore the accidents are poorly documented, and usually not

witnessed by independent observers. Secondly, the investigating authorities and

manufacturers tend to prematurely blame the rider for the accident. Thirdly, an

unusual combination of circumstances has to occur for such accidents to happen.

These involve the motorcycle type and setup, the speed, the lean angle, the

rider's stature and the road profile. Finally, the underlying mechanics of these

phenomena are complex as the chassis or frame is not strong enough to sustain such

a huge load. Apart from the social costs and loss of life, motorcycle accidents can

also cause large financial costs.

There is therefore an increasing need to gain a complete understanding of the

behavioral properties of single track vehicles and to seek solutions to any problems.

The knowledge acquired can be used in the design, testing and development process

to cut down costs associated with trial-and-error methods that are employed by

manufacturers, and could aim at increasing rider safety and other quality features

such as maneuverability and handling. Further to that, skills can be developed that

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could be used for rider training purposes. The dynamic stability under small

perturbations from straight running and steady cornering conditions for motorcycles

has been studied extensively prior to this work.

A plastic or fiberglass shell, known as a fairing, is often placed over the

frame, to shield the rider from the wind. Drag is the major factor that limits

motorcycle speed, as it increases at the cube of the velocity. Despite the streamlined

appearance of new performance motorcycles, there is still virtually no aerodynamic

technology included in the design, and motorcycles still effectively push their way

through the atmosphere with brute force. This is generally due to the fact that no

designs have been discovered that can improve aerodynamic performance without

unacceptably compromising the rider's ability to control the machine. In the absence

of a fairing or windshield, a phenomenon known as the windsock effect occurs at

speeds above 100 km/h, where the rider becomes a major source of drag and is

pushed back from the handlebars, tiring the rider.

1.2 Project title

Simulation Stress and finite element analysis based of a Suzuki FXRI50cc

motorcycle chassis

1.3 Project objective

To investigate the most critical pointl joining of chassis part for vehicle (Suzuki

FXR1 50cc)

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1.4 Project scopes

i. Using CAE software to determine the experimental and finite element

ii. The chassis investigate is based of Suzuki FXR1 50cc motorcycle with the

aim of its frame as major data contribution.

1.5 Problem statement

In order to build a successful motorcycle, manufacturer or designer must first

look at its most fundamental component, the chassis. The major data distribution on

the motorcycle is the frame. The motorcycle will require a frame design that has been

computer generated and analyzed; also it must be fabricated and structurally tested.

To ensure a successful motorcycle especially the frame, extensive Finite element

analysis (FEA), as well as a number of non destructive tests. Attention to the critical

areas of the chassis especially the frame, and insure future success through design

analysis evolution is the main criteria.

A flexible frame acts as a spring and can absorb and reduce the effects of

some types of loading, if only parts of the frame are stiffened then we may pass more

load through to the unstiffened areas which may deform locally more than before

even though the whole frame deforms less. Therefore, the major data contribution of

critical joining due to the frame failure will be investigated through this thesis.

5

1.6 Flow chart

Determination on the objective, scope, and the problem statements

Literature study, journal, reference books

Literature review and the methodology/experimental methodology

Understanding the topic

1 St presentation

Actual measurement on SUZUKI FXR150cc motorcycle chassis

Design using the J Analysis using the solidwork algor

Result

Conclusion

Report

2 nd presentation

End

Figure 1.1 Final year project flow chart

CHAPTER 2

LITERATURE REVIEW

2.1 Introduction

The purpose of this Chapter is to give an overview of the state of knowledge

on the chassis behaviors of single-track vehicles up to date. The issues covered are

presented roughly in chronological order and relate to theoretical studies through

finite element analysis (FEA) and also to experimental results and observations on

Suzuki FXR15Occ motorcycle chassis.

The Suzuki FXRI5O "Cybermatic Sports Cruiser" is powered by 4-stroke 147

cc engine. Produced in Malaysia by Lion Suzuki Motor Sdn Bhd with 75% local

content, it is sold for RM9000. It replaced the slighty larger in size 2-stroke Suzuki

RG15O/RGVL5O. It features a full digital dash which displayed fuel, RPM, speed

and gear. Top speed is around 140 - 150 km/h.

Even though the scientific study of the motions of two-wheelers has been in

progress for more than 100 years, early work was progressing slowly and many

conflicting conclusions were drawn initially. Over time, moment and force producers

evolved to include the effects of various frame flexibilities and rider dynamics. The

major data contribution for the motorcycle is due the failure of the frame.

I

2.2 Fundamental of chassis

Chassis means the rectangular, usually steel frame, supported on springs and

attached to the axles, that holds the body and motor of an automotive vehicle. The

Suzuki FXRI5O "Cybermatic Sports Cruiser" frame is made of box cut steel and had

a banana shaped rear swing arm, it has a single mono shock on the rear with a single

disk brake. The front suspension is a traditional telescopic fork also with a single

disk brake. The wheels are 5 spoke Enkei mag type wheels.

The engine has a six-speed close ratio gearbox with a kickstart and electric

start. The engine features a small oil cooler to aid cooling. The system "motorcycle"

may be considered to consist of two parts. The rear frames including the rider, the

engine, the petrol tank and the seat and rear wheel. The front frame consists of the

forks, the handlebars and the front wheel.

2.3 Geometrical definition

Firstly, there are the geometrical definitions. These dynamical measurements

determine how the bike behaves while being ridden. The motorcycle chassis consists

of wheelbase, wheel alignment, sprocket alignment, rake and trail, offset, center of

gravity, ride height, engine ground clearance and swing arm. Also there are frame,

absorber, suspension, fork, steering, brake and tyre.

The frame is the largest part and it gives a large data distribution of the

Suzuki FXRI5Occ failure. The position of these is very important due to the chassis

stitThess.

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2.3.1 Wheelbase

Wheelbase is the distance between the centers of rotation for the front and

rear wheels - that is, the distance between the front and rear axle. Typical numbers

are 55 to 58 inches for mid-size and larger street sporting motorcycles, 52 to 54

Inches for 250 or 500cc Grand Prix bikes and just under 50 inches for 125cc GP

bikes.

2.3.2 The wheel alignment and sprocket alignment

The wheel alignment and sprocket alignment is mostly same means that the

front and rear wheel are in-line. That is, they point in the same direction and are not

offset from each other. Rake is the angle of inclination with respect to the vertical of

the axis of rotation about which the front wheel is turned during the steering process.

This is usually the angle with respect to the vertical of the steering head of the frame.

2.3.3 Trail and offset

Trail is the distance, as measured along the ground, of the point at which the

front tire contacts the ground and the axis of rotation would contact the ground. The

perpendicular distance between a line drawn through the centers of the fork tubes and

the steering stem center of a triple clamp is called offset. Sometimes the top and

bottom triple clamps do not have the same offset. In that case the trail and wheelbase

(but not the rake) are altered.

MI

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2.3.4 Ride height

Moreover, ride height is the height of the front of the motorcycle (typically

measured from one of the triple clamps) and the height of the rear of the motorcycle.

The true purpose of changes in ride height is to affect a change in the location of the

center of gravity.

2.3.5 Center of gravity

Then, center of gravity is the center of mass of the entire motorcycle, without

rider. It is usually located somewhat above and behind the crankshaft of the engine.

The exact location of the center of mass is an important quantity in the design of top-

level racing motorcycles. In the context of an entirely uniform gravitational field,, the

center of mass is often called the center of gravity- the point where gravity can be

said to act.

The center of mass of a body does not always coincide with its intuitive

geometric center, and one can exploit this freedom. The center of mass frame also

called the center of momentum frame is an inertial frame defined as the frame in

which the center of mass of a system is at rest. The center of mass R, of a system of

particles is defined as the average of their positions ri, weighted by their masses m1:

R = M rnr(2.1)

Where;

M is the total mass of the system, equal to the sum of the particle

masses.

10

For a continuous distribution with mass densityp(r), the sum becomes an

integral:

1 f fp(r)rdV

R=/rdrn=Mjp(r)r = fp(r)dV (2.2)

If an object has uniform density then its center of mass is the same as the

centroid of its shape. Usually the engine ground clearance on modern slicks allows

really good riders to exceed the theoretical maximum 45 degree lean angle at which

the centrifugal and gravitational forces are balanced.

2.3.6 Engine fore and pivot position

Furthermore, the engine fore position always needed when installation of the

rider usually makes the bike tail heavy. So a forward engine position is needed.

Lastly, swing arm pivot position is important because as the pivot moves away from

the center the change in chain tension increases and cause darn. The swing arm pivot

should be as close to the countershaft sprocket as possible.

IF Fig.4 i SSSInU Md.

V*Veai

a L

- i,— Fd tI trai l

R.r whe trail

Figure 2.1 Geometrical definition of motorcycle (Dr. Rob Tuluie, 2005)

11

2.4 Effects of vibration modes of motorcycle to frame

2.4.1 Theories

An important step in the theoretical analysis of motorcycles was achieved by

(Sharp, 197 1). Sharp carried out a Lagrangian analysis of the motions of a motorcycle

with a rider, treating the vehicle as two rigid frames joined at an inclined steering

axis, the rider being rigidly attached onto the rear frame. Four degrees of freedom

were allowed, lateral motion, yaw, roll and steer, and only small perturbations from

straight running were considered in the motion, essentially making the model linear.

The tyres were assumed as producing steady state forces and moments that

were linearly dependent on side-slip and camber angle, with the instantaneous forces

and moments obtained from the steady state ones via a first order differential

equation that modeled the tyre relaxation property. The free control analysis exposed

some important results. It predicted the presence of important modes throughout the

speed range, some of which were oscillatory. These were given the names "capsize",

"weave" and "wobble".

2.4.2 Weave

Weave is a low frequency (2-3 Hz) oscillation of the whole vehicle involving

roll, yaw and steer motions, and is well damped at moderate speeds but becomes

increasingly less damped and possibly unstable at higher speeds. An oscillation of

the rear frame around the steering axis called the weave mode.