Article citation information:
Hadula, P., Kaczmarczyk, Ł., Fabiś, P. Powertrain
damage analysis for Formula Student car WT-02. Scientific Journal of Silesian University of Technology. Series
Transport. 2017, 95, 47-53. ISSN: 0209-3324. DOI: https://doi.org/10.20858/sjsutst.2017.95.5.
Przemysław HADULA[1],
Łukasz KACZMARCZYK[2],
Paweł FABIŚ[3]
POWERTRAIN DAMAGE ANALYSIS FOR
FORMULA STUDENT CAR WT-02
Summary. This paper is a summary of the design and
workmanship of a Formula Student transmission system vehicle. We conducted
simulation research on transmission system damage. Damage occurred during the
Formula Student competition, which is why we needed to improve the drivetrain
system. The article proposes a variant of the change brackets and carrying out
simulation studies on the new construction. For selected models, the
transmission system, which is also determined by its impact on strength and
reliability, is driven by a four-cylinder engine with a displacement of 0.6 dm3.
Keywords: Formula Student; transmission;
driveline; MES simulation.
1. INTRODUCTION
Formula Student is an international
competition between teams from universities and technical faculties around the
world, which is organized by SAE International. The idea behind the competition
is to design and produce a racing vehicle in accordance with the rules of the
competition. The car created by each must be finished car in a given time and
in line with the need to gain knowledge, strengthen discipline, cooperation and
foresight, and often make compromises. Gained in such circumstances, experience
and knowledge are invaluable and important aspects of training top-notch
engineers. Undoubtedly, this is also a chance to test their skills in the real
world, under the pressure of time and project requirements. What matters is not
only the maximum speed of the car, but the balance between a number of
important elements, namely, speed, economy of operation, aesthetics,
functionality and safety. Victory in the competition only goes to those teams
that are able to present a complete project and receive the highest number of
points. With the Formula Student competition, students have the chance to
establish contacts with local industry, while the industry has the opportunity
to support the development of its potential future executives. The basis for
the competition is undoubtedly to support the development of technical thought,
while emphasizing how important it is to create technical universities. As
engineering students and professionals play a huge role in human development,
they are of great value to society.
2. CHARACTERISTICS OF THE FORMULA STUDENT COMPETITION
Formula Student is the largest international event organized by the Institution of Mechanical Engineers and directed mainly at students of technical universities. The patronage of the cycle of competitions includes the most distinguished engineers associated with the automotive industry and motorsport (including F1). The aim of the competition is primarily to find talented students and compare the design of vehicles from all over the world. The competition consists of two stages: the first is to present a vehicle design and the second is to build the vehicle according to a detailed specification from SAE International. During the competition, the judges strictly evaluate each project in terms of its design and engineering approaches. Furthermore, the vehicle is tested from static and dynamic perspectives, which is why the notion that this is a typical sport competition recedes into the background.
The static part is devoted to the broader business side and involves preparing a cost production schedule, developing a business plan and presenting on the special features of the project (i.e., design). The second part is directly related to the dynamic competitions involving the designed and manufactured vehicles. Admission to the dynamic part of the competition is possible after the painstaking verification of the technical research aspects of each vehicle:
1. Verification as to whether the vehicle complies with the provisions of SAE International’s procedural rules (scrutineering)
2. Verification of the centre of gravity (tilt)
3. Measurement of engine noise (noise test)
4. Verification of the brakes system (brake test)
The positive completion of all of these tests enables the dynamic events to start, which are concerned with time measurement and include:
1. Driving on the track in the shape of a figure eight (skid pad)
2. Accelerations of the car at a limited distance (accelerations)
3. Driving on parts of the track (autocross)
4. 20 km main race (endurance)
Points are allocated in the course
of these event by professionals, with the totals determining whether the
vehicles will receive specific investments at the end of the competition.
3.
TRANSMISSION SYSTEM
CONSTRUCTION FOR THE FORMULA STUDENT CAR
The object of the research is a racing
class Formula Student WT-02 vehicle equipped with a four-cylinder, four-stroke
SI engine, with a capacity of 600 cm3. Originally, this engine was
powered by a carburetted system, which, in the course of adapting the engine to
the vehicle, was converted to a multipoint injection system.
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Fig. 1. View of the car and its
transmission system |
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During the project construction, in
order to increase the dynamic qualities of the vehicle, a charging system was
applied using a turbocharger. The test transmission and the vehicle are shown
in Fig. 1.
The car was equipped with a torque
transfer from the engine to the wheels via a chain motorcycle. Torque
distribution between the wheels is possible through the use of Drexler’s
differential (Fig. 2).
Fig. 2. Visualization of the Formula
Student car’s the transmission system
A differential mechanism, including
a main gear, was attached to the vehicle frame, irrespective of the engine and
the gearbox. This allowed the separation of the drive system of the vibration
from the engine.
4. TRANSMISSION SUPPORT MESH SIMULATION RESULTS
When designing the drive system of
the vehicle and its attachments, the weight of the vehicle was reduced in line
with the adopted criteria. Every element of the vehicle, including th
powertrain, was subjected to the
optimization of weight. The result of these assumptions was the need to
simulate important endurance elements affecting the safety and operation of the
vehicle systems.
During test drives carried out under
track conditions, the bracket of the main gearbox and the differential broke
down. The damaged components are shown in Fig. 3.
Fig. 3. Transmission support damage
of the Formula Student car
On these photographs, a visible
rupture can be seen, along with the broken part of the bracket located on the
main gearbox of the vehicle.
Fig. 4. Transmission system mesh of
the Formula Student car
Simulation testing in SolidWorks
2016 was carried out in order to determine how to fix the problem, as well as
improve stability in terms of securing and increasing the vehicle’s strength.
Fig. 4 shows the grid as applied to the powertrain components.
The differential was modelled and
simplified in order to obtain the most real values of stresses in the material
during drive operations. The upper part of the fixing devices was fitted to the
frame’s lower part by the steel brackets. The simple interface between the
fasteners reflected the differential gears, which transmit force to the
clamping differential. Applying the force has a direction and a return
consistent with the operation of the drive chain. A force of 10 Kn was applied
to the model, which reflected the strength with which the engine torque was
transmitted through the chain to the differential. The original fitting of the
differential stress values significantly exceeded the value of the elastic
limit.
Fig. 5. Transmission system
simulation of the Formula Student car
Modified support for the
differential helped to significantly increase the rigidity and strength of the
structure; at the same time, there was hardly any increase in the mass of the
system. Tests exactly reflected the point of possible damage to the original
structure. By applying force to the new
support, the differential had a value of 20 kN, which is twice the value
assumptions. During the test, in addition to the classic mesh, possible damage
was caused to the local thickening grid. The results of simulation testing are
shown in Fig. 5.
Fig. 6. Improved transmission system
mesh of the Formula Student car
On the basis of the
simulation, the place of greatest deformation was determined, as well as the
loads that corresponded to the site of injury during the test drives.
Appropriate modifications were carried out in order to increasing the vehicle’s rigidity, again by
simulating the FEM. Results of the simulation are shown in Fig. 6 and Fig. 7. The
modifications consisted of changing the profile of the external support and
partial filling of the parent material. These changes effectively improved the
rigidity and strength of the bracket.
Fig. 7. Improved transmission system
simulation of the Formula Student car
The value of
the maximum destructive forces to support the revised powertrain was 20 kN.
5. CONCLUSIONS
In this
study, the powertrain simulation allowed for an increase in the reliability of
the vehicle. A strength analysis was carried out using SolidWorks 2016, which
precisely defined the location of the damage. The research led to the following
conclusions:
1. Changes
in the structure of the bracket resulted in increased stiffness and mechanical
strength
2. Design
changes necessitated an increase in the weight of the bracket, while the
reliability of the vehicle increased under track conditions
3. Changing
the construction of the transmission support provided an increase in the force
by 200%
It
seems reasonable to continue research on the optimization reliability of the
car and find some way in which to reduce weight.
References
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Bąk
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Elements of Computer Recognition. Warsaw:
Science and Technology Publishing House]. ISBN: 13 978-83-7926-048-5.
2. SAE
International. 2015. 2015 Formula SAE Rules. Warrendale, PA: SAE International.
3.
Durand
Keith. 2005. Design of a Chain Driven
Limited Slip Differential and Rear Driveline Package for Formula SAE
Applications. Bachelor of Science thesis. Massachusetts Institute of
Technology.
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Kurowski
Paul. 2013. Engineering Analysis with SolidWorks Simulation
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Received 29.01.2017; accepted in revised form 27.04.2017
Scientific Journal of Silesian
University of Technology. Series Transport is licensed under a Creative
Commons Attribution 4.0 International License
[1] Faculty of Transport Silesian
University of Technology Krasinskiego 8 street 40-019 Katowice, Poland.
Email:
przemysla.hadula@gmail.com
[2] Faculty of Transport Silesian
University of Technology Krasinskiego 8 street 40-019 Katowice, Poland.
Email:
lukaszz.kaczmarczyk@gmail.com
[3] Faculty of Transport Silesian
University of Technology Krasinskiego 8 street 40-019 Katowice, Poland.
Email:pawel.fabis@polsl.pl