investigation of rollover performance for...

INVESTIGATION OF ROLLOVER PERFORMANCE FOR MALAYSIA BUS

SUPERSTRUCTURE

MOHAMMAD AMIRUL AFFIZ BIN AFRIPIN

UNIVERSITI TEKNOLOGI MALAYSIA

INVESTIGATION OF ROLLOVER PERFORMANCE FOR MALAYSIA BUS

SUPERSTRUCTURE

MOHAMMAD AMIRUL AFFIZ BIN AFRIPIN

A thesis submitted in fulfilment of the

requirements for the award of the degree of

Master of Engineering (Mechanical)

Faculty of Mechanical Engineering

Universiti Teknologi Malaysia

APRIL 2014

iii

Special dedicated, in thankful appreciation for support, encouragement and

understanding to my beloved parents, Mak (Noraini binti Onan), Abah (Afripin bin

Nong) and my siblings Afrizani, Ika, Aqila and Affiza.

iv

ACKNOWLEDGEMENTS

First and foremost, all praise be to Allah, the most merciful to His creation

and give me strength to complete this study and to see this thesis becomes a reality.

Through the process of creation and completion of this thesis, many people had

contributed directly and indirectly from knowledge, moral and money supports.

Therefore, I would like to express my gratitude to my supervisor, Associate

Professor Mustafa bin Yusof, the members of CSM laboratory, Mohd Shauqy Amin,

Mohd Aliff, Amir, the members of the Solid Mechanics laboratory, Mohd Fadli,

Mohd Zakaria and all other laboratory technicians of the faculty of Mechanical

Engineering, Universiti Teknologi Malaysia for assisting me in planning,

brainstorming, writing, editing and correcting stages of this project and thesis.

I am indebted and would like to express my appreciation to Fundamental

Research Grant Scheme (FRGS) for providing me the fund to complete this study. I

also would like to extend my thankfulness to Universiti Teknologi Malaysia for

providing me with the high technology facilities in completion of this research.

Lastly but not least, I am thankful because having really lovely parents,

Afripin Nong, Noraini Onan and siblings, Afrizani, Zulaikha, Aqila, Affiza that

understand me and always be there for me.

Thanks to all.

v

ABSTRACT

Accidents involving bus rollover can be classified as one of the most fatal

types compared to other types of motor-vehicle accident. There are various aspects

that lead to occupant injury and fatality. Two prominent aspects are superstructure

strength and occupant kinematics. This study deals with the two stages of analyses

which are superstructure strength having rollover and occupants kinematic analysis.

In accordance to UNECE R66, the bus superstructure should be able to withstand the

impact load produced by the rollover accident. The validation process using finite

element model was done by comparing the strain results obtained from simple box

rollover experiment with the simulation results. A total of four full-scale models of

the bus superstructures had undergone rollover simulation using finite element

analysis software. The predicted results suggested that the structural strength having

rollover strongly depends on the bus design parameters in terms of the beam profile

size and main bus dimensions. Analyses of the occupant kinematics were also

included in this study. Occupant’s injury of restraint occupant was compared to

unrestraint occupant using the Mathematical Dynamic Model (MADYMO) software.

Overall, the injury indexes for unrestraint occupant are greater than that for restraint

occupant. By using a restraint system, the occupant injury and number of fatalities

can significantly be reduced.

vi

ABSTRAK

Kemalangan yang melibatkan bas berguling boleh dikategorikan sebagai

kemalangan paling bahaya jika dibandingkan dengan jenis kemalangan yang lain.

Terdapat pelbagai aspek yang menyebabkan kecederaan dan kematian kepada

penumpang. Dua aspek yang terpenting adalah kekuatan rangka bas dan kinematik

penumpang. Tesis ini merangkumi dua peringkat kajian iaitu analisis kekuatan

rangka bas yang berguling dan analisis kinematik penumpang. Berdasarkan piawaian

yang ditetapkan oleh UNECE R66, struktur rangka bas perlu mempunyai kekuatan

yang cukup bagi menahan hentakan yang berpunca daripada kesan bas berguling.

Proses pengesahan bagi kaedah unsur terhingga telah dijalankan melibatkan

perbandingan keputusan terikan antara eksperimen gulingan kotak mudah dan

simulasi gulingan kotak mudah. Empat buah bas terlibat dalam proses simulasi bas

berguling dengan menggunakan perisian kaedah unsur terhingga. Hasil analisis

mengesahkan kekuatan struktur bas yang mengalami kemalangan bas berguling

bergantung kepada rekabentuk bas yang terdiri daripada saiz profil rasuk, dan ukuran

utama dalam bas. Analisis kinematik penumpang juga turut dimasukkan ke dalam

kajian ini. Kecederaan yang dialami oleh penumpang yang memakai tali pinggang

keledar dibandingkan dengan penumpang tanpa tali pinggang keledar dengan

menggunakan perisian model dinamik matematik (MADYMO). Secara umumnya,

indeks kecederaan yang dicatat oleh penumpang tanpa tali pinggang keledar melebihi

penumpang yang memakai tali pinggang keledar. Dengan menggunakan sistem

sekatan, kecederaan penumpang dan seterusnya kematian dapat dikurangkan.

vii

TABLE OF CONTENTS

CHAPTER TITLE PAGE

DECLARATION ii

DEDICATION iii

ACKNOWLEDGEMENTS iv

ABSTRACT v

ABSTRAK vi

TABLE OF CONTENTS vii

LIST OF TABLES xii

LIST OF FIGURES xiv

LIST OF ABBREVIATIONS xix

LIST OF SYMBOLS xxi

LIST OF APPENDICES xxii

1 INTRODUCTION 1

1.1 Background of the Study

1.1.1 Bus Definition and Classification

1.1.2 Rollover Classification

1.1.3 Main Occupants Injury Mechanism due to

rollover

1.1.4 Bus Accident Cases in Malaysia

1

3

5

9

9

1.2 Statement of Problem 12

1.3 Objective of the Study 13

1.4 Scope of the Study

1.5 Research Question

13

14

viii

1.6 Significance of the Study 14

2 LITERATURE REVIEW 15

2.1 Introduction

2.2 Types of Road Vehicle Accident

2.3 The Rollover Process

2.3.1. Rollover Initial Condition

15

16

17

17

2.4 Previous Study

2.4.1 Bus Rollover Accident Statistics

2.4.1.1 Bus Accident Statistic in Malaysia

2.4.2 Relationship of Bus Design to Rollover

Performance

2.4.3 Validation between Real Testing and Virtual

Testing

2.4.4 Occupant Kinematic and Safety Belt

18

19

21

23

24

25

3 RESEARCH METHODOLOGY 28

3.1 Introduction

3.1.1 Flowchart of the Methodology

28

30

3.2 Research Instruments

3.2.1 Instruments Used in Simple Box Rollover

Experiment

3.2.2 Software Used in Simulation

3.2.2.1 Dummy Database

3.2.2.2 Injury Parameters

3.2.2.3 UNECE R66

3.2.2.3.1 UNECE R66 Rollover Test

Method

31

31

33

34

35

37

32

37

3.3 Subject of the Study 40

3.4 Data Analysis 40

3.5 Research Procedure 41

4 RESULTS & DISCUSSION 49

ix

4.1 Introduction 49

4.2 Bus Superstructure Study

4.2.1 Validation Results

4.2.1.1 Simple Box Rollover Experiment

4.2.1.2 Virtual Test FE Model Validation

4.2.2 Profile Beam Variation

4.2.2.1 Simulation of Bus Design With

Profile of Cant-Rail and Horizontal

Roof Beam Based on Manufacturer

Specifications

4.2.2.2 Simulation of Bus Design with


Roof Beam Using 75x50x3.8

Millimeters (Largest Beam Used In

Bus Superstructure)

4.2.2.3 Simulation of Bus Design with


Roof Beam Using 12x25x1.6

Millimeters (Smallest Beam Used In

Bus Superstructure)

4.2.2.4 Beam Profile Variation Discussion

4.2.3 Rollover Analysis of Various Bus

Superstructure

4.2.3.1 Single Deck Coach Type A

4.2.3.2 Single Deck Coach Type B

4.2.3.3 City Transit Bus Superstructure

4.2.3.4 Double storey Coach

4.2.3.5 Various Design Rollover Simulation

Discussions

50

50

50

52

55

57

59

61

61

62

63

67

71

75

79

4.3 Occupant Kinematic Study

4.3.1 Various Occupant’s Sitting Position

4.3.1.1 Hybrid III 50th

Percentile at Driver

Seat Position

83

84

84

x


Percentile at Passenger

1 Seat Position (Front – Opposite

Rollover Side)



2 Seat Position (Front – Near

Rollover Side)



3 Seat Position (Rear – Opposite

Rollover Side)



4 Seat Position (Rear – Near

Rollover Side)

4.3.1.6 Discussion for Various Locations

4.3.2 Seat Belt Utilization


Percentile Using

Safety Belt at Driver Seat

Position


Percentile Using

Safety Belt at Passenger 1 Seat

Position (Front – Opposite Rollover

Side)


Percentile Using


Position (Front – Near Rollover

Side)


Percentile Using


Position (Rear – Opposite Rollover

Side)


Percentile Using


Position (Rear – Near Rollover

Side)

88

91

94

97

100

103

103

106

108

110

112

xi

4.3.2.6 Discussion for Safety Belt Utilization

114

5 CONCLUSIONS 119

REFERENCES 127

Appendix A 129

Appendix B 135

Appendix C 141

Appendix D

xii

LIST OF TABLES

TABLE NO. TITLE PAGE

2.1 Spain Injury Distribution, 1995-1999

20

2.2 Characteristics of Bus Accident in Malaysia based on

MIROS from 2007 to 2009

22

4.1 Dimensions of Box Model

51

4.2 Simulation Properties

53

4.3 Dimensions used in Bus model

57

4.4 Lists of Beam Profile

58

4.5 Dimensions of Single Deck Coach Type A Superstructure

63

4.6 Value of Masses

63

4.7 Dimensions of Single Deck Coach Type B Superstructure

67

4.8 City Transit Bus Superstructure Dimensions

71

4.9 Dimensions of Double Storey Coach Superstructure

75

4.10 Variation of Maximum Von-Mises Stress

79

4.11 Bus Superstructure Dimensions

82

4.12 Injury Values of Hybrid III dummy at driver position

87

4.13 Injury Values of Hybrid III dummy at passenger 1 seat

position (front - opposite rollover side)

90


position (front - near rollover side)

93

xiii


position (rear - opposite rollover side)

96


position (rear - near rollover side)

99

4.17 Comparison between injuries by seat location

102

4.18 Injury Values of Hybrid III dummy using safety belt at

driver position

105


passenger 1 seat position (front - opposite rollover side)

107


passenger 2 seat position (front - near rollover side)

109


passenger 3 seat position (rear – opposite rollover side)

111


passenger 4 seat position (rear - near rollover side)

113

4.23 Comparison of injury parameters for belt and unbelted

occupant located at driver seat

116


occupant located at passenger 1 seat

116



117



117



118

xiv

LIST OF FIGURES

FIGURE NO. TITLE

PAGE

1.1 Motor coach Fatal Events (FARS 1999-2008)

5

1.2 Vehicle trip-over

6

1.3 Vehicle fall-over out of the road

6

1.4 Vehicle flips-over

7

1.5 Vehicle bounce-over after rebound with a fixed object

7

1.6 Vehicle turn-over due to centrifugal force resisted by

normal surface friction

7

1.7 Vehicle climbs over a fixed object

8

1.8 Vehicle rolls on its lateral axis

8

1.9 Bus Superstructure after having a rollover accident in

Genting Highlands

10

1.10 Bus Superstructure Having Rollover Accident at

Cameron

10

1.11

Bus Superstructure Having Rollover Accident at Bukit

Gantang

11

2.1 The free body diagram of bus rollover forces 17

2.2

Data of Bus Accidents in Indonesia [12]

20

2.3

Trend of bus accidents and registered buses in Malaysia

[14]

21

2.4

Bus Accidents Casualties [14] 22

2.5

Identification of occupants initial positions [27] 26

3.1 Flowchart of the Methodology 30

xv

3.2 Strain Gauge Attached on Simple Bus Section

32

3.3 Simple Bus Section Used for Real Test Rollover [34]

32

3.4 Simple Box Used for Real Test Rollover [35]

32

3.5 Element and Nodes

33

3.6 Ellipsoidal Dummy Models

35

3.7 Geometry of tilting platform [3]

38

3.8 Recommended field of view for outside camera [3]

39

3.9 3D CAD Model

42

3.10 Model geometry of the bus superstructure

43

3.11 Residual space of the bus structure and mass distribution

44

3.12 Rollover Platform Setting

45

3.13 Bus Rollover model in MADYMO

46

3.14 Dummies Seat locations

47

3.15 Injuries contour in rollover and non-rollover accidents

[36]

48

4.1 Real Testing Box Model [35]

51

4.2 Portable Data Logger UPC 601-G [35]

51

4.3 The plot of strain obtained from dynamic strain

measuring system [35]

52

4.4 Simple Box Model

53

4.5 Maximum Strains results obtained from Simulation of

box rollover

54

4.6 Simple Box Rollover Sequence

54

4.7 Beams involve in the beam profile modification process

56

4.8 Standard Beam Rollover Result

58

4.9 75x50x3.8 mm Beam Rollover Result

59

xvi

4.10 General Stiffness of Bus Superstructure [37]

60

4.11 Local Stiffness of Cant-Rail [37]

60

4.12 12x25x1.6 mm Beam Rollover Result

61

4.13 Graph of Maximum Von-Mises Stress

62

4.14 Side view drawing of Single Deck Coach Type A

superstructure

64

4.15 Rollover Sequence of Single Deck Coach Type A

65

4.16 Single Deck Coach Type A Bus Superstructure at First

Contact

65

4.17 Graph of Kinetic and Internal Energy of Single Deck

Coach Type A Rollover Simulation

66

4.18 Side view drawing of Single Deck Coach Type B

superstructure

68

4.19 Rollover Sequence of Single Deck Coach Type B

69

4.20 Single Deck Coach Type B Bus Superstructure at First

Contact

69

4.21 Graph of Kinetic and Internal Energy of Single Deck

Coach Type B Rollover Simulation

67

4.22 Side view drawing of City Transit Bus Superstructure

72

4.23 Bus Rollover Sequence for City Transit Bus

Superstructure

73

4.24 City Transit Bus Superstructure at first contact

73

4.25 Graph of Kinetic and Internal Energy of City Transit

Bus Superstructure

74

4.26 Side view drawing of Double Storey Coach

superstructure

76

4.27 Rollover Sequence of Double Storey Coach

77

4.28 Double Storey Coach Bus Superstructure at First

Contact

77

xvii

4.29 Graph of Kinetic and Internal Energy of Double Storey

Coach Bus Superstructure position (front - near rollover

side)

78

4.30 Cant-Rail Location

80

4.31 Beam Arrangement for City Transit (Left) and Coach

Bus (Right)

80

4.32

Side view drawing of various bus superstructures. (Left

Elevation)

81

4.33

Side view drawing of various bus superstructures.

(Right Elevation)

81

4.34 Location of Human Dummy Model in MADYMO

85

4.35 Kinematics of Hybrid III dummy at driver position

86

4.36 Kinematics of Hybrid III dummy at passenger 1 seat

position (front - opposite rollover side)

89


position (front - near rollover side)

92


position (rear – opposite rollover side)

95


position (rear - near rollover side)

98

4.40 Bus Superstructure Deformation Diagram

101

4.41 Kinematics of belted Hybrid III dummy at driver

position

104

4.42 Kinematics of belted Hybrid III dummy at passenger 1

seat position (front - opposite rollover side)

106

4.43

Kinematics of belted Hybrid III dummy at passenger 2

seat position (front - near rollover side)

108

4.44


seat position (rear – opposite rollover side)

110

4.45


seat position (rear - near rollover side)

112

xviii

4.46 Comparison Between Belt and Unbelted Occupant

Kinematic

115

xix

LIST OF ABBREVIATIONS

USA - United States of America

FARS - Fatality Analysis Reporting System

SCI - Spinal Cord Injury

TBI - Traumatic Brain Injury

UNECE - United Nation Economic Commission of Europe

NHTSA - National Highway and Traffic Safety Administration

Km - Kilometers

Plus - Projek Lebuhraya Usahasama Berhad

a.m. - ante meridiem

FEM - Finite Element Method

MADYMO - Mathematical Dynamic Model

NASS - National Automotive Sampling System

CDS - Crashworthiness Data System

FEA - Finite Element Analysis

ASME - American Society of Mechanical Engineer

ECBOS - Enhanced Coach and Bus Occupant Safety

CAE - Complete Abaqus Environment

TASS - TNO Automotive Safety Solutions

MADPost - MADYMO post-processing program

GSI - Gadd Severity Index

HIC - Head Injury Criterion

TTI - Thoracic Trauma Index

EuroSID - Side Impact Dummy

HybRID - Rear Impact Dummy

xx

AIS - Abbreviated Injury Scale

NIC - Neck Injury Criterion

VC - Viscous Injury Response

Mm - Millimeter

xxi

LIST OF SYMBOLS

SR - Seat Reference Point

∝ - Alpha (angle)

ho - Vertical Height

t - Transverse distance

L1 - Longitudinal distance

xxii

LIST OF APPENDICES

APPENDIX TITLE PAGE

A Bus Classification According to Country

127

B Regulation 66 Requirements 129

C Graph of Injury

135

D Software Description

141

CHAPTER 1

INTRODUCTION

1.1 Background of the Study

Bus can be described as prevalent transport worldwide. Progressively more

individuals are choosing bus due to the convenience offer over other public transport

services. Usually bus can accommodate up to 40 passengers. If accident occurred, it

will jeopardize many occupants. Besides, rollover accident itself is one of the main

accidents that can lead to severe injury and sometimes death to bus occupants. This is

showed by bus rollover accident happened in Genting Highlands involved 37

fatalities. Furthermore, this type of accident can lead to severe injury and

subsequently, affect the daily life of rollover victim. Besides, most of the factory

used bus to transporting workers. If accident occurred, it will effect on company

productivity. Thus, national productivity can decrease due to workers health

problem. Burns et al. [1], found that rollover incidence frequently becomes a major

factor of Spinal Cord Injury (SCI). In the United States, 30 percent of SCI cases

came from rollover accidents. Furthermore, rollover victims also exposed to

Traumatic Brain Injury (TBI). In that case, the occupant’s impact with roof can lead

to head injury and TBI [2].

2

Present knowledge on bus rollover accident’s study related on occupant

kinematics and strength of various bus superstructure designs is inadequate. Most

researchers only focus on the effect of bus roof strength towards severity of rollover

accidents without considering occupant kinematic. According to United Nation

Economic Commission of Europe (UNECE) Regulation 66 [3] which is uniform

technical prescription concerning the approval of large passenger vehicles with

regard to the strength of their superstructure, bus can operate on the road if

superstructure not infringes into residual space during impact and post-impact. The

ultimate goal of rollover test as mentioned in the regulation is to minimize the

intrusion of superstructure into the occupant compartment. However, it might be

possible that occupant’s life still in danger although that superstructure passes the

test due to the failure of occupant kinematic consideration.

Most of previous study used a simulation method according to Annex 9,

UNECE R66 [3]. Annex 9 allows bus manufacturers to evaluate its new bus

superstructure design crashworthiness in rollover events using computer simulation

while following real test condition (Annex 1).

Most of the rollover accident involving roof crushes will result higher rate of

spine injury, brain injury and mortality [4]. Apart from weak bus superstructure,

another factor that leads to occupant injury is rapid movement of occupant during

rollover. This kinematic movement also known as diving hypothesis as introduced by

Moffat [4]. Moffat [4] discovers that, in a rollover crash, the roof of the vehicle is

stationary against the ground and occupants will speed subsequently impact the roof

due to inertia. Consequently, high load acted on the occupant’s body resulting spine

injury.

Another cause of occupant injury is occupant ejection outside bus

superstructure [5]. It can be prevented by maintaining structural integrity of bus

superstructure. By strengthening the joint and other critical parts, the structure has a

higher possibility of preserving its shape after having rollover accident. Other ways

3

to avoid this incident is seat belt usage especially for front seat occupant and using

laminated windows. Therefore, if these features are implemented in bus coach, there

is a possibility that occupants will not eject outside bus frame.

However, these previous findings are not includes the effect of various

designs on bus superstructure. Apart from that, occupant injuries only take by

statistical data without proper occupant simulation in rollover case. More in-depth

studies are needed to confirm these findings.

Aside from the studies conducted on the factors that affected the strength of

bus superstructure having rollover, there is an important need to determine the best

bus superstructure design that can withstand rollover impact. This is because many

factors can affect bus superstructure deformation after rollover such as total weight,

material used, size of window and floor. These factors need to be determined to

provide better survival space for occupants. Therefore, both factors those cause

kinematic injuries which introduced by Moffat [4] need to be covered in this study.

1.1.1 Bus Definition and Classification

A bus can be defined as a large motor vehicle carrying passengers by road,

especially that serving the public for a fare and has a schedule. Its classification is

commonly done by referring to its seating capacity, capable of load carriers, body

style, service provided, stopping pattern and other physical or usage based feature.

In Malaysia, bus can be classified into two main types which are single storey

and double storey bus [6]. The single storey bus represents a single deck for

passengers and the height range is from 3 to 3.5 meters. Usually the length for this

4

type of bus is basically range from 5 to 12 meters but for some countries, up to 15

meters is permissible due to its operation road which needs to be wide and straight.

There are 2 types of single deck bus which are low and high floor. It is important to

recognize that the addition of a wheelchair ramp at the entrance and barrier-free

facilities for low floor are 2 main features that can be seen clearly in order to distinct

between low and high floor single deck. Usually, low floor bus is used for transit and

it help wheelchair users and senior citizens to access the bus easily due to the

smallest gap between the road surface and bus floor. High floor bus normally

designed for coach usage or long journey travel. Furthermore, extra space under the

passenger seat is use for luggage storage.

Double storey buses can be divided into two types according to their usage

which are double deck and high deck [6]. Double deck commonly used for double

storey transit bus. It has a low floor for better accessibility and better headroom for

the lower deck. Maximum of 100 passengers can board on this bus at one time. 55

seats passengers are located on the upper deck while estimated of 28 seats located on

the lower deck. Standing position is allowed for lower deck passengers while upper

deck passengers need to seat properly due to space constraint and wheelchair bay is

also provided as a facility for wheelchair users. High deck is the term used for double

storey bus that operates for a long journey travel. Most of the passenger seats are

located on upper deck. Passengers for this type of bus are not more than 50.

Buses are also known with others unique terms such as Omnibus, Motor

coach and Autobus [7]. Until now, there were no single universal legal definition for

the bus and it changes widely by nations. Therefore, it is very difficult to identify the

crashworthiness aspects of different types of buses originate from lack of a shared

definition and the missing harmonized classification for buses. Generally, most of the

country use length, weight and vehicle’s passenger as their criteria for bus

classification [7]. Legal definition for bus according to respective country is in

Appendix A.

5

1.1.2 Rollover Classification

Compared to the other type of accidents, rollover is the most critical accident

based on number of fatalities and severe injuries. Figure 1.1 shows the type of

accident percentages (Source from Fatality Analysis Reporting System (FARS) for

the USA market):

Figure 1.1 : Motor coach Fatal Events (FARS 1999-2008)

Surrounding and road surface condition of the accident scene has strongly

influenced the type of rollover accident. Therefore, rollover accident can be

categorized into two main types which are:

1. Tripped: this occurs when the vehicle’s tire comes in contact with an object

that sudden stop the lateral motion of the vehicle and initiates the vehicle into

roll condition around that object. Tripping objects usually are curbs, rock,

soils and ramp.

2. Untripped: the main cause for this accident is severe steering maneuvers

such as J-hooks, fast turns and instant lane changes. This accidents different

with tripped because rollover happens without trip object and more focus on

change of center of gravity location rapidly.

Rollover 44%

Multi Vehicle 33%

Roadside object 19%

Other 4%

6

According to National Highway and Traffic Safety Administration (NHTSA),

Rollover can be classified by referring to its commencing reasons. The definitions

include the following factors:

1. Trip-over: When vehicle wheels dig into a curb, pavement or pothole, the

lateral motion of the vehicle will suddenly slow or stopped inducing

rollover. Figure 1.2 shows the vehicle trip-over diagram.

Figure 1.2 : Vehicle trip-over

2. Fall-over: When the vehicle center of gravity becomes outboard of its

wheels. The movement of center of gravity caused by vehicle travelling

slopes downward in the direction of its movement. The difference

between this type of rollover and turn-over is negative slope. Figure 1.3

displays vehicle fall-over out of the road.

Figure 1.3 : Vehicle fall-over out of the road

3. Flip-over: When a vehicle hit ramp like object such as back slope of a

ditch or a turned down guardrail, it will rotate around its longitudinal axis.

The illustrations for vehicle flips-over show in Figure 1.4.

7

Figure 1.4 : Vehicle flips-over

4. Bounce-over: When a vehicle overturns after rebounds off a fixed object.

The rollover needs to occur close to the fixed object as shown in Figure

1.5.

Figure 1.5 : Vehicle bounce-over after rebound with a fixed object

5. Turn-over: When a vehicle taking sharp turns and centrifugal forces

produced resisted by normal surface friction caused the vehicle to roll as

shown in Figure 1.6.

Figure 1.6 : Vehicle turn-over due to centrifugal force resisted by normal

surface friction

8

6. Collision with another vehicle: When a vehicle roll immediately after hit

or hit by another vehicle

7. Climb-over: When a vehicle pass over a high fixed object such as barrier

or guardrails and that object is high enough to lift the vehicle off the

ground as shown in Figure 1.7.

Figure 1.7 : Vehicle climbs over a fixed object

8. End-over-end: When a vehicle rolls about its lateral axis. Sometimes

happen when vehicle apply sudden break and load transfer to the front.

Figure 1.8 illustrates the vehicle rolls on its axis.

Figure 1.8 : Vehicle rolls on its lateral axis

9

1.1.3 Main Occupants Injury Mechanism due to rollover.

Four main injuries during rollover that may endanger the occupants are listed

as follows [5]:

1. Intrusion: Happen if bus superstructure cannot withstand impact from

rollover accident and then having large deformation. Consequently, structures

infringe into residual space and contact with the occupant’s body.

2. Projection: It is due to the rapid kinematic movement of the occupants inside

the bus that hit structural parts inside bus compartment.

3. Partial Ejection: This type of mechanism happens when an occupant’s body

part such as leg, arms or head is partially eject outside bus superstructure

frame.

4. Complete Ejection: It is almost the same with partial ejection but the

difference is instead of the occupant’s body partially ejected, from this

mechanism, occupant’s body fully ejected from the bus superstructure

through the opening like window and door.

1.1.4 Bus Accident Cases in Malaysia

Recently, numbers of bus accident case occurred in Malaysia keep increasing

from time to time. The worst bus accident case was recorded until now occurred on

21st August 2013 at 2.15 P.M. The accident which took place near Chin Swee

Temple, Genting Highlands Pahang involving fatality of 37 passengers and 16 others

were injured. The bus carrying 53 passengers lost control as it was going down an

10

incline and it plunged into a deep ravine at about 60 meters at the kilometer 3.5 of

the Genting Sempah – Genting Highlands Highway. The bus driver died on the spot.

Figure 1.9 illustrates the bus superstructure after rollover happened.

Figure 1.9 : Bus Superstructure after having a rollover accident in Genting Highlands

On the other events, on 20th

December 2010, one of the worst accident cases

happen involving 27 dead, mostly Thai tourists. This tragedy occurred at Cameron

Highland when the bus was lost control as going down the road and hit the middle

divider subsequently landed on the other side of the road. Then, the bus was rollover

and roof of the bus was ripped off as shown in Figure 1.10.

Figure 1.10 : Bus Superstructure after having a rollover accident in Cameron

11

The other accident that involving a high number of fatalities was happened on

14th

August 2007 involving 22 passenger fatality and injury of 7 passengers. It takes

place at km 229, North-South Plus Highway near Bukit Gantang around 4.45 a.m.

The bus superstructure was plunge into a ravine and its roof was ripped off as shown

in Figure 1.11.

Figure 1.11 : Bus Superstructure Having Rollover Accident at Bukit Gantang

Based on rollover scenario, the strength of roof and superstructure play an

important role to protect occupant from any harm. Therefore, the bus manufacturers

need to ensure their bus provide high level of safety before operating on the road and

the authority need to enforce the law to elude weak bus superstructure from operating

on the road.

12

1.2 Statement of Problem

Malaysia has experienced a dramatic growth in the number of fatalities in bus

rollover accident case. In 2007, one dramatic bus rollover crash involving fatality of

22 passengers that took place near Bukit Berapit, Bukit Gantang. Since then, most of

Malaysian much more concern for bus superstructure safety. This accident shows

that bus superstructure needs to be strong enough to withstand rollover impact and

provide better survival space for occupants. Adequate design and sufficient strength

of bus superstructure can reduce the number of injuries and fatalities.

Given the situation, it is time to takes serious effort in studying factors that

can give extra strength to bus superstructure related to bus design and the needs of

safety belts as passive safety feature to avoid occupant’s projection movement and

ejection from bus superstructure.

In order to fully lessen occupant injury, diving hypothesis need to be

investigated. Thus, in this research, the relationship between belt and unbelted

passenger was studied to observe the injury on human dummy model.

13

1.3 Objective of the Study

The objectives of this study are:

1. To investigate the performance of various designs of bus superstructure

during a rollover accident.

2. To study a numerical simulation of occupant kinematics and interaction with

the interior bus features during rollover.

3. To make recommendation on the safe superstructure design.

1.4 Scope of the Study

On the issue of bus superstructure rollover and its effect on occupant

kinematics, the following activities have to be carried out in order to achieve the

objectives of the research:

1. Simulation of simple box: It includes the simulation of simple frame using

finite element analysis software to check the reliability and acceptability of

results from simulation. The results were compared with simple box

experiment.

2. Simulation of full-scale bus frame: It includes the simulation of bus frame

using finite element analysis software to observe the effects of impact due to

the rollover.

3. Simulation of occupants inside bus interior: Simulation of human dummy

model using Mathematical Dynamic Model software to observe the effect of

restraint system on occupant injury.

4. To give recommendations on the possible and relevant improvement in the

design of Malaysia bus frame to enhance the strength of superstructure.

14

1.5 Research Question

1. What are the effects of different design of the bus superstructure on bus

rollover?

2. What are the interactions between occupant and bus interior when rollover

happened?

3. What are factors that can improve superstructure strength and reduce injury to

occupants?

1.6 Significance of the Study

From this research, the design specification of bus superstructure was

identified which has the potential to improve current bus superstructure strength. In

addition, the utilization of restraint system has significantly reduced the injury on

occupants having rollover accident.

122

REFERENCES

1. Burns, S.M.C., Kaufman R, Bulger E. Cost of Spinal Cord Injuries Caused by

Rollover Automobile Crashes. in Injury Prevention. 2010.

2. Jingwen Hu., J.B.L., King H. Yang, and Albert I. King. Injury Patterns and

Sources of Non-Ejected Occupants in Trip-Over Crashes: A Survey of NASS-

CDS Database from 1997 to 2002. in Annu Proc Assoc Adv Automot Med.

2005.

3. UNECE, ECE R66 Uniform Technical Prescriptions Concerning The

Approval Of Large Passenger Vehicles With Regard To The Strength Of

Their Superstructure. 2004.

4. Moffatt, E.A., Occupant motion in rollover collisions, in 19th Conference of

the American Association of Automotive Medicine. 1975: San Diego, CA.

5. Matolcsy, Ejection of Passengers in Bus Rollover Accidents, in Proceedings

of the FISITA 2012 World Automotive Congress. 2012: China.

6. Anon. Assessment of Bus Types and Usages. 2009 [cited 2013 25th May];

Available from: http://www.miros.gov.my

7. Resta, G., International Standard for Protection of Occupant in Rollover

Accidents, in Complaint Bus For Tomorrow Workshop, Malaysia. 2012.

8. Paul, D.B., Clifford, C.C., Fileta, B.B., Khalil, B.T., Albert, I.K., Hikmat,

F.M., Harold, J.M., Jac, M, Vehicle Crashworthiness and Occupant

Protection, in American Iron and Steel Institute. 2004: Michigan.

9. Rasenack, W., Appel, H., Rau, H., and Rieta, C, Belt Systems in Passenger

Coaches, in Fifteenth International Technical Conference on the Enhanced

Safety of Vehicles. 1996: Australia, 1996.

10. Botto, P., Caillieret, M.C., Patel, A., Got, C., and Tarriere, C., Passenger

Protection in Single and Double-Decker Coaches in Tipping Over, in 13th

International Technical Conference on Experiential Safety Vehicles. 1991:

Paris, France.

11. Anon., Initiatives to Address the Mitigation of Vehicle Rollover. 2003.

12. Indera N, R.Z., Sandro M, Kyaw S.O., Computer Modeling of Energy

Absorbing Capability of Bus Superstructure for Rollover Safety. Journal of

KONES Powertrain and Transport, 2011. 18(No. 2 2011).

http://www.miros.gov.my/

123

13. Martínez, L., et al., Improving occupant safety in coach rollover.

International Journal of Crashworthiness, 2003. 8(2): p. 121-132.

14. Solah M.S., A.A.H., Isa M.H., Wong S.V., In-Depth Crash Investigation on

Bus Accidents in Malaysia. Journal of Society for Transportation and Traffic

Studies. Journal of Society for Transportation and Traffic Studies, 2011. 3(1).

15. Langwieder, K., M. Danner, and T. Hummel, Collision types and

characteristics of bus accidents, their consequences for the bus passengers

and the accident opponent: 10. Internat. Technic. Conference on

Experimental Safety Vehicles (ESV) Oxford July 1985. 1985: HUK-Verb.

16. Bish, J., Nash, Carl E., Paskin, Allan, Honikman, Terence and Friedman,

Donald, An Evaluation of Production Vehicle Roof Strength, in ASME

International Mechanical Engineering Congress and Exposition. 2004:

California, USA.

17. Brian Herbst, D.H., Steven E. Meyer, Stephen Forrest, Anthony Sances and

Sriringham Kumaresan, Epoxy Reinforcing for Rollover Safety, in ASME

International Mechanical Engineering Congress & Exposition. 2004:

California, USA.

18. L. Castejón, D.V., R. Miralbés, M. Carrera, J. Cuartero, C. Martín. New

concept of rollover resistant semitrailer for hydrogen transport. in 19th

International Conference On Design Theory And Methodology. 2007. Las

Vegas, Nevada, USA.

19. White, D.M., P.S.V. Rollover Stability, in 10th International Technical

Conference on Experimental Safety Vehicles. 1985.

20. Roper, L.D. (2001) Physics of Automobile Rollovers.

21. Schwer, L.E., An Overview of the ASME Guide for Verification and

Validation in Computational Solid Mechanics. 2006.

22. Koji Kumagai, Y.K., Hidehiko Enomoto, Shigeaki Shimojima, An analysis

method for rollover strength of bus structures. JSAE Review, 1995. 16(1): p.

103.

23. Gürsel, K.T.S.G., Analysis of the superstructure of a designed bus in

accordance with regulations ECE R66. Gazi University Journal of Science,

2010. 23: p. 71-79.

124

24. Zhang, G., X. Zhang, and B. Liu, The Study of Bus Superstructure Strength

Based on Rollover Test Using Body Sections, in Advances in Multimedia,

Software Engineering and Computing Vol.2, D. Jin and S. Lin, Editors. 2012,

Springer Berlin Heidelberg. p. 315-322.

25. Gerd Scholpp, J.S., Mike Linstromberg, Evelyn Winter, Correlation of

Human and Dummy Movement during Rollover Situations, in 10th

International MADYMO Users Meeting. 2004: Amsterdam.

26. Deshmukh, P.S., Rollover and Roof Crush Analysis of Low-Floor Mass

Transit Bus, in Department of Mechanical Engineering. 2002, Wichita State

University.

27. Anon., Final Report Enhanced Coach and Bus Occupant Safety (ECBOS), in

European Commision 5th Framework, Project Number 1999-RD.1130. 1999.

28. Parenteau, C., Gopal, Madana and Viano, David, Near and Far Side Adult

Front Passenger Kinematics in a Vehicle Rollover, in SAE 2001 World

Congress. 2001: Detroit, MI, USA.

29. Ferrer, I., and Miguel, J.L., Assessment of the Use of Seat Belts in Busses

Based on Recent Road Traffic Accidents in Spain, in 17th International

Technical Conference on the Enhanced Safety of Vehicles. 2001: Amsterdam,

the Netherlands.

30. Thomas, T.M., Marine, Micky C., Wirth, Jeffrey L.,Peters, Brian W.,

Emergency-Locking Retractor Performance in Rollover Accidents, in ASME

International Mechanical Engineering Congress & Exposition. 2002 New

Orleans, Louisiana, USA.

31. Albertsson, P., et al., Case study: 128 injured in rollover coach crashes in

Sweden—Injury outcome, mechanisms and possible effects of seat belts.

Safety Science, 2006. 44(2): p. 87-109.

32. Meyer, S.E., Forrest, Steven and Brian, Herbst, RestraintSystem Performance

and Injry Potential to Belted Occupants in Automobile Rollover Crashes, in

ASME International Mechanical Engineering Congress and Exposition.

2006: Chicago, Illinois, USA.

33. Chang, W.-H., et al., Association between major injuries and seat locations in

a motorcoach rollover accident. Accident Analysis & Prevention, 2006.

38(5): p. 949-953.

125

34. Mukhlas, M.N., Simulation of Rollover Test Using Body Section Of A Bus

Based On UNECE Regultion 66 As An Approval Method, in Department of

Mechanical Engineering. 2009, Universiti Teknologi Malaysia: Johor.

35. Ali, M.L., Impact on Bus Superstructure due to Rollover, in Department of

Mechanical Engineering. 2008, Universiti Teknologi Malaysia: Johor.

36. Linstromberg M, S.G., Scherf O, Test and Simulation Tools in a Rollover

Protection Development Process, in Siemens restraint systems GmbH, ESV

Conference. 2005: Washington, USA.

37. Matolcsy, M., The Severity Of Bus Rollover Accidents, Scientific Society of

Mechanical Engineers.

38. LE, C.-C.L.a.G.-N., Optimization Of Bus Rollover Strength By Consideration

Of The Energy Absorption Ability. International Journal of Automotive

Technology, 2010. 11(2): p. 173-185.

39. Kamruzzaman, S., Energy Absorption Of Tubular Structures, In Mechanical

Engineering. 2000, Texas Tech University: Texas.

40. Wu, C.C.C.A.F., Development Of Madymo-Based Model For Simulation Of

Laboratory Rollover Test Modes. Passive Safety Research And Development

Research And Advanced Engineering. Ford Motor Company

41. Almusallam, A.A., Mathematical modeling of rollover accidents. 1989,

Marquette University: Ann Arbor. p. 337-337 p.

42. Funk, J.R., J.M. Cormier, and S.J. Manoogian, Comparison of risk factors for

cervical spine, head, serious, and fatal injury in rollover crashes. Accident

Analysis & Prevention, 2012. 45(0): p. 67-74.

43. Freeman, M.D., et al., Serious head and neck injury as a predictor of

occupant position in fatal rollover crashes. Forensic Science International,

2012. 222(1–3): p. 228-233.

44. Kwasniewski, L., et al., Crash and safety assessment program for paratransit

buses. International Journal of Impact Engineering, 2009. 36(2): p. 235-242.

45. Dobbertin, K.M., et al., The relationship between vehicle roof crush and

head, neck and spine injury in rollover crashes. Accident Analysis &

Prevention, 2013. 58(0): p. 46-52.

46. Friedman, K., J. Hutchinson, And D. Mihora, Biomechanical Evaluation Of A

Rollover Occupant Protection Subsystem. Journal Of Biomechanics, 2007.

40, Supplement 2(0): P. S131.

126

47. Zhao, S., et al., Analysis of damage in laminated automotive glazing

subjected to simulated head impact. Engineering Failure Analysis, 2006.

13(4): p. 582-597.

48. Ramu, M., V. Prabhu Raja, and P.R. Thyla, Establishment of structural

similitude for elastic models and validation of scaling laws. KSCE Journal of

Civil Engineering, 2013. 17(1): p. 139-144.

49. Wen-Hsian Chang, H.-R.G., Hung-Jung Lin ,Yu-Hern Chang, Association

between major injuries and seat locations in a motorcoach rollover accident.

Accident Analysis and Prevention, 2006. 38: p. 949–953.

50. Grzebieta, R., Young, David, McIntosh, Andrew, Bambach, Michael,

Frechede, Bertrand, Tan, Guohui, Achilles, Rollover crashworthiness : The

final frontier for vehicle passive safety. 2007, Meeting Planners.

51. A.H. Iskandar, Q.M.L., Ageing Effect on Crashworthiness of Bus Rollover, in

9th European LS-Dyna Conference 2013. 2013.

investigation of rollover performance for...

Documents