IRJET- Lightweight and Multi Material Designing and Analysis of a C9 Bus Frame Superstructure Considering ECE 066

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 06 Issue: 03 | Mar 2019 www.irjet.net p-ISSN: 2395-0072
© 2019, IRJET | Impact Factor value: 7.211 | ISO 9001:2008 Certified Journal | Page 1745
Lightweight and Multi Material Designing and Analysis of a C9 Bus
Frame Superstructure Considering ECE 066
Aditya U Patil1, Rushikesh N Pawar2, Shubham S Patil3, Kundan V Pachpande4
1,2,3,4BE Students, Mechanical Engineering, G H Raisoni College of Engineering and Management , Wagholi , Pune ,
Maharashtra , India
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Abstract - If we see the evolution of Transportation system
over the years, we draw an important inference that Buses
undebatably have been a major mode of Transport. At the
same time, we also observe the increasing inclination of
people towards safety measures for mass transportation.
The design of the bus body depends upon various
parameters including road conditions, loading conditions,
passenger capacity, type of usage, centre of gravity etc.
These parameters are useful concerning safety as well as
economics of manufacturing. Based on the above
characteristics, the material, the size of the compnents.
The paper presents an attempt of optimizing design of a K9
bus superstructure and at the same time bring the centre of
gravity at the correct position by the correct material
considering rollover.
1. INTRODUCTION
A Spanish survey showed that the frequency of rollover
was 4% of all coach accidents on roads and highways, and
the risk for fatalities in a rollover was five times higher as
compared to any other type of accident . Another statistic
of Fatality Analysis Reporting System (FARS) also showed
that rollover occurs less frequently than all other types of
automotive accidents, but the probability of fatalities and
severe injuries is more in rollover type accidents. Thus,
rollover strength has become an important issue for bus
and coach manufacturers.
1.1 PRESENT SYSTEM
The bus manufacturers are now a days experimenting
with various materials other than the conventional
materials such as low carbon steel to take advantage of
various other materials available in the market (especially
non-ferrous) considering their specific properties. If
properly designed & analyzed, these new type of materials
helps in enhancing the structural mechanical properties.
The following figure shows the 3-d modeling of type II
K9D bus.
Fig 1.1: Type II K9D bus.
1.2 EXISTING PROBLEM
As mentioned before buses are important modes of travel
& hundreds of people travel by them everyday. Their
capacity may differ from 10-12 to 40-50 people. If an
accident is caused due to rollover & the super structure
deforms beyond the specified limit, it may seriously
threaten the lives of passengers inside the bus.
Hence, prevention of rollover phenomenon & designing
the superstructure with optimum strength, stiffness,
weight is an important task for bus manufacturer.
For prevention of bus rollover failure, the legislation
regulation number 66 of economic commission for Europe
(ECE R66) has been enforced. Following of ECE R66 has to
be done along with reducing the weight of the structure &
prevention of superstructure from entering the residual
space.
1.3 IMPROVISATION
While using a material for superstructure, various
properties of material including strength, mass, weight,
size, density along with corrosion prevention, rusting
prevention, their thermal properties has to be considered.
1.3.1 MILD STEEL
Because of low cost & various desirable properties, mild
steel is the most commonly used material for building
superstructure. It can be formed easily & although it has
low tensile strength, low cost and high forming properties
make it a suitable choice for super structure. Its surface
hardness can be increased by carburizing. Since they have

less amount of carbon as compared to other steels, they
can be easily formed by cold forming process. If we
consider larger cross sections to reduce deformation of
materials, then mild steel is the best choice.
1.3.2 MILD STEEL YST310
Mild steel YST310 is preferred because of its better
compressive strength due to lower slenderness ratio and
high yield strength. It has full strength under bending
moment regardless of lateral restrains due to superior
torsional rigidity. It also has low drag coefficients of closed
of closed structure helps to bypass the fluid currents more
effectively then conventional sections. It enhances the
shear capacity due to more effective area under shear.
Because of light weight, the seismic forces on the structure
will be less, there by reducing the weight on the structure.
1.4 OBJECTIVE
Hence this paper presents light weight optimization
considering the bus rollover crashworthiness design. In
this study, all the sections including R.H. section, L.H.
section, roof section, top section are to be critically
examined in order to prevent the intrusion in residual
space. Some of the examples of rollover of buses is shown
n following diagrams.
1.5 METHODOLOGY
• Study of failure of the K9 Bus frame structure due
to rollover
2. GEOMETRIC MODELLING
In this section, the detailed CAD models used in project are
shown. CAD modeling software such as CATIA is used. The
overall dimesions of various section of the bus
superstructure are shown in figure.
Fig 2.1: Front Structure
Fig 2.2: Rear Structure
Fig 2.3:L.H. Structure

Fig 2.4:R.H. Structure
Fig 2.5:Roof Structure
Fig 2.6:Floor Structure
Designing of the superstructure serves as one of the
most important fact of the Bus production process. Out of
the above shown diagram, no structure should enter the
residual space of the passengers to provide a rollover
preventive superstructure. The assembly of the above
parts is shown in the figure.
Fig 2.7: CAD model of bus frame superstructure
Table 2.1: General properties of the bus
3. DESIGN ANALYSIS
Fig 3.1:Intrusion Analysis
Table 3.1: Intrusion Analysis
The above diagram shows the intrusion analysis of the
shaded parts. It can be seen that all the measurements and
the values of extrusion are positive and within their limits.
Hence it shows that no part of the superstructure enters
the residual space of the bus superstructure and hence the
structure can be said as rollover preventive.
Fig 3.2: Strength Analysis
The above analysis in the software shows that Local
failure is observed but overall strength meets the
requirments.
Table 3.2: Energy Absorption
3.1 AUTOMOTIVE STANDARD ECE R66
REQUIREMENTS
1. The superstructure of the vehicle shall have the
sufficient strength to ensure that the residual space during

and after the rollover test on complete vehicle is
unharmed.
-Superstructure of the vehicle for modification model with
SWR is 6.80 which is satisfying the above standard
requirement.
2. No part of vehicle which is outside the residual space at
the start of the test (e.g. pillars, safety rings, luggage racks)
shall intrude into the residual space during the test. Any
structural parts, which are originally in the residual space
(e.g. vertical handholds, partitions, kitchenettes, toilets)
shall be ignored when evaluating the intrusion into the
residual space.
-Satisfying the above standard requirement. (Residual
space has been maintained and not intruded by any other
object during impact.)
3. No part of the residual space shall project outside the
counter of the deformed structure. The counter of the
deformed structure shall be determined sequentially,
between the every adjacent window and the door pillar.
Between two deformed pillars the counter shall be a
theoretical surface, determine by straight line, connecting
the inside counter points of the pillar which were the same
height above the floor level before the roller rest.
-Satisfying the above standard requirement.
4. RESULT
As mentioned above, the superstructure analysis clearly
states that it is safe from rollover failure. All the
regulations reguarding ECE 066 were followed and there
was reduction in weight with optimizing of
superstructure. As per the analysis in the software LS
Dyna, Local failure was observed but overall strength
meets the requirments. Also no part of any superstructure
was intruding in the residual space of the superstructure.
All these results show that the process of using the metal
YST 310 was successful.
5. Conclusion
In this projectwork, designing and dynamic analysis is
done on the baseline model with Mild steel YST 310.Here
the software Catia was used for designing of the
superstructure initially and then analysis was done on the
software LS Dyna.
By the above result and analysis, we can say that the
modified model with material Mild Steel 310 is extremely
crashworthy. Along with it, the superstructure was
optimized reguarding the weight, its centre of gravity
resulting in stabilizing of the structure.
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2. Yuan Ren, Yongchang Yu, Binbin zhao, Chuanhui Fan, He
Li, ” Finite Element Analysis and Optimum Design for the
Frame of SX360 Dump Trucks”, Procedia Engineering 174
(2017)
3. Petros Evgenikos, George Yannis, Katerina Folla, Robert
Bauer, Klaus Machata, Christian Brandstaetter, “
Characteristics and causes of heavy goods vehicles and
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4. D. Senthil Kuma, “ Rollover Analysis of Bus Body
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5. G. Gruben, O.S.Hopperstad, T.Borvik, “ Evaluation of
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