Innovative Design of an All-Terrain Vehicle (ATV)

Prévia do material em texto

International Journal of Engineering and Advanced Technology (IJEAT) 
ISSN: 2249 – 8958, Volume-3, Issue-2, December 2013 
151 
 
 
Abstract— This study aims to design of an All-Terrain Vehicle 
(ATV) in accordance with the SAE BAJA 2014 rule book. A 
detailed designing of components is carried out like Roll cage, 
Suspensions & Braking mechanism. The main focus of our was 
on Safety of driver & Stability of vehicle. Roll cage of our vehicle 
is designed in such a way that in case of rolling of vehicle (mostly 
occurs in high speed turns & off roading) that it will provide 
double the strength to the roll cage with also considering the 
Aesthetic of the cage. International standards are followed by us 
where ever possible and an extensive market survey is also done. 
Finite Element Analysis is carried out on roll cage & braking 
mechanism for optimum safety & reliability of the vehicle. Engine 
the heart of an automobile is installed in such a way that it can 
perform well for an extensive time on any terrain. 
Index Terms—Cooling duct, Ergonomics, Finite element 
Analysis & Von misses stress. 
I. INTRODUCTION 
The objective of the study is to design a safest vehicle for 
driver. The roll cage is being strictly designed in accordance 
with SAE BAJA 2014 rule book. 3D Assembly of whole 
vehicle & Line model of the roll cage is modelled in PTC 
Creo 2.0. Finite element analysis (FEA) is carried out on line 
model of roll cage in cases of front collision, rear collision, 
rolling, front bump & Rear bump analysis in Ansys. FEA of 
suspension arms was carried out in Catia & FEA of Braking 
mechanism in Solidworks. Based on the result obtained from 
above tests the design is modified accordingly. 
The Centre of Gravity was tried to keep in middle of the 
vehicle & closest to the ground for optimum stability. The 
length of the vehicle was kept small so as to reduce weight and 
maintain a desired center of gravity, while the width of the 
vehicle was keep the most to maintain stability in turns. 
II. ROLL CAGE DESIGN & ANALYSIS 
Design of a roll cage consists of numerous factors like 
material selection, pipe size selection, frame design and finite 
element analysis. These each steps are elaborated further. 
A. Material Selection 
As per the rule book constraint there should be at least 
0.18% of carbon content in metal. Our initial step was to 
conduct a market survey to have an idea of the availability of 
the material. 
Based on market survey we have chosen following material 
namely:- 
 
Manuscript received December 2013 
Harsh Raghuvanshi, Mechanical department, Echelon Institute of 
Technology, Faridabad (Haryana), India. 
N.S. Ramnaveen, Mechanical department, Echelon Institute of 
Technology, Faridabad (Haryana), India. 
Puneet Malhotra, Mechanical department, Echelon Institute of 
Technology, Faridabad (Haryana), India. 
Rakshit, Mechanical department, Echelon Institute of Technology, 
Faridabad (Haryana), India. 
Anurag Khatri, Mechanical department, Echelon Institute of 
Technology, Faridabad (Haryana), India. 
• AISI 1020 
• ASTM A 106 Grade B 
• IS 2062 
A comparative study of the chosen material was done for 
our use. The methodology for material selection followed by 
us are as follows. 
 
Consideration Priority 
Availability Necessary 
Carbon Content Necessary 
Strength High 
Cost High 
Weight Necessary 
On above factors these three material where compared the 
final selection of the material are as follows on basis of carbon 
content, tensile strength, yield strength & density. 
 
Name Carbon 
Content 
Tensile 
Strength 
(MPa) 
Yield Strength 
(MPa) 
AISI 1020 0.20% 394.7 294.8 
ASTM A 106 
Grade B 0.30% 415 240 
IS 2062 0.22% 410 240 
 
On the above comparison ASTM A 106 Grade B was 
selected. The properties of this material are 
Density (x 1000 kg/m3) 7.7-8.03 
Poisson’s ratio 0.27-0.30 
Elastic Modulus (GPa) 190-210 
Tensile Strength (MPa) 415 
Yield Strength (MPa) 240 
Elongation (%) 20 
Reduction in Area (%) 48 
Hardness (HRB) 100 
B. Pipe Size Selection 
We were having a constraint in selection of size for 
secondary members of the frame that the minimum wall 
thickness should be 0.89 mm (0.035 in) and min outside 
diameter should be 25.4 mm (25.4 in). 
To select a standard pipe size we followed ASME 
B36.10M which is an international standard for welded and 
seamless wrought steel pipes. 
Identification [Standard 
(STD), Extra-Strong 
(XS), Strong (XXS)] 
Outside Diameter 
(mm) 
Wall 
Thickness 
(mm) 
XS 26.7 (Secondary Member) 3.91 
XS 21.3 (A-arms) 3.73 
C. Frame design 
The crucial objective of the frame is to provide a safe 
driving environment to the driver keeping in mind the weight, 
Innovative Design of an All-Terrain Vehicle (ATV) 
Harsh Raghuvanshi, N.S. Ramnaveen, Puneet Malhotra, Rakshit, Anurag Khatri 
 
Design & Analysis of an All-Terrain Vehicle (ATV) 
152 
space & cost. Roll cage was designed in such a way that it 
should withstand driver weight, bump loads, engine and 
transmission load. It was also required to keep a minimum 
clearance of 3 in between driver & roll cage members. Pedals 
of brake & accelerator were installed at the extreme front 
position so as to reduce the length of the roll cage from front 
and give that extra length to rear which results in sustaining 
the center of gravity in the middle of the vehicle. Our main 
focus was also to provide a better viewing angle to the driver 
so we opt for a curved front members of the roll cage. This 
curved member also provide support to the roll cage in case of 
rolling. 
After fulfilling the all the given constraints in the rule book 
a 3D model was designed. 
 
Fig 1. Modelled frame 
 
Our design methodology in designing a roll cage were 
some parameters on which certain priorities were listed. A 
table representing such parameters with priority & reason is 
shown 
S.NO 
CONSIDERATI
ON 
 
PRIORITY 
 
REASON 
 
1 Light Weight 
 
Necessary A light weight Buggy is fast 
2 
Meet 
Requirements 
 
Essential 
 
Must not deform 
during rugged 
driving 
4 Simple Frame 
 
Essential 
 
Majority of frame 
fabrication done in 
College 
5 Attractive Design 
 
Desired 
 
Easier to sell an 
aesthetically 
pleasing vehicle 
6 Cost 
 
Low 
 
Car needs to be 
within budget 
7 Manufacturability 
 
High 
 
Manufacturing is 
done in the College 
D. Analysis results 
After completion of design of the roll cage we need to find 
that our roll cage will perform well in field so we performed 
analysis in Ansys. 
 
Fig 2. Roll over analysis (Von misses stress= 97.93 MPa) 
 
 
 
Fig 3. Front impact Analysis (Von misses stress= 42.9 MPa) 
 
 
 
Fig 4. Rear impact Analysis (Von Mises stress= 53.79 MPa) 
 
International Journal of Engineering and Advanced Technology (IJEAT) 
ISSN: 2249 – 8958, Volume-3, Issue-2, December 2013 
153 
 
 
Fig 4. Front bump Analysis (Von Mises stress= 14 MPa) 
 
 
Fig 6. Front impact Analysis (Von misses stress= 37.9 MPa) 
 
In Ansys maximum Von mises stress is calculated and is 
represented by colour coding. 
These stresses are evaluated to find the factor of safety & 
certain remarks were given. 
E. Conclusion 
� Hence for design purposes force is taken to be 7000N. 
� Also, design output is for no plastic deformations. The 
vehicle should remain in the elastic region. 
� The Safety of the driver in case of crash is taken care of 
by safety equipment which includes special helmets, 
foam padding on bars and seat belts. 
� The Design Factor of Safety, FS d is taken as 2. This 
relatively high value is taken to account for the 
uncertainty in the nature of forces.III. SAFETY CONSIDERATION 
 
Fig 7. Similar Curvatures 
• Curved FBM (Front Bracing Members) & RRH(Rear 
Roll Hoop) 
• A five point racing harness 
• Two Kill switches are used in supporting rod of steering 
column and behind the firewall 
• Other important safety equipments such as brake light, 
Reverse light, reverse alarm and fire extinguisher 
• Dual Pipe Front bumper 
• Under Seat Member (USM) 
• Wide exit 
• Casings are done between steering and FAB (Fore/Aft 
Bracing) 
• A minimum of 6 inch vertical distance from driver’s 
head to the bottom of RHO(Roll Hoop Overhead 
members) and a 3inch clearance between body and 
roll-cage. 
• Better stability due to less distance b/w roll center and 
C.G 
IV. ERGONOMICS 
� Outward bend of FBM gives large front vision to Driver 
� Firewall at 12 degree gives good seating posture to 
Driver 
� SIM are made low for the ease of egress 
� Auto centrifugal clutch 
� Gear shifter on left side 
� Dashboard inclination 
� Rotor coil starter above the shoulder 
� Side mirrors 
V. COOLING DUCT 
Due to position of the Air cooled engine (Behind firewall) 
there was no means of air striking the engine. We decided to 
place an Air deflecting duct at side of our roll cage. 
 
 
 
 
 
S.
N
O 
TEST Force 
Applie
d 
Factor 
of 
Safety 
Result Remark 
1 Roll 
over 
Analysis 
7000N 
 
2.14 No 
Yielding 
Slight 
tilt in 
RHO 
and 
effect on 
FBM 
2 Rear 
Impact 
Analysis 
7000N 
 
3.9 No 
Yielding 
Safe and 
impact 
is taken 
by LSM 
3 Front 
Impact 
Analysis 
7000N 
 
4.89 No 
Yielding 
Safe and 
impact 
is taken 
by LSM 
4 Front 
wheel 
Bump 
Analysis 
1500N 
 
15 No 
Yielding 
Bump is 
taken by 
FAB 
5 Rear 
wheel 
Bump 
Analysis 
1500N 
 
6 No 
Yielding 
Bump is 
taken by 
rear 
bracing 
 
Design & Analysis of an All-Terrain Vehicle (ATV) 
154 
 
 
Fig 8. Cooling duct 
This duct was having bigger inlet section (A1) & smaller 
outlet section (A2) to accelerate the air. 
 
Area of input section (A1) =11542.75 mm2 
Area of output section (A2) =7310.11 mm2 
Input velocity (max. air velocity) (V1) = 50 km/hr 
 
A1 * V1 = A2* V2, 
11542.75 *50 =7310.11 * V2 
V2 =78.95 km/hr 
 
Output Velocities at different speeds 
 
Sr. No 
V1 
(km/hr
) 
A1/ A2 
V2 
(km/hr) 
1 15 1.579 23.69 
2 25 1.579 39.48 
3 40 1.579 63.16 
4 50 1.579 78.95 
 
VI. SUSPENSION 
Due to functioning of vehicle in all terrains, the suspension 
should be robust. The methodology followed by us is. 
A. Design Selection 
 
Fig 9. Suspension system 
• We have selected Double Wishbone suspension for the 
front and rear to reduce the unsprung weight and get a 
maximum camber gain during cornering. 
• Design Arms controls the motion of the wheels 
throughout the suspension travel and controls the wheel 
alignment parameters, like Caster angle camber angle, 
toe, roll center height and scrub radius. 
 
 
Fig 10. Caster angle Determination: 5.12 degree 
 
 
Fig 11. SAI angle Determination: 8 degree 
Front Suspension Double Wishbone Suspension 
(Unequal arms) 
Rear Suspension Double Wishbone Suspension 
(Unequal arms) 
Camber 1-2 degree (NEGATIVE) 
Caster 5 degree (POSITIVE) 
Steering Axis Inclination Angle 8 degree 
Scrub Radius 90 mm 
Length of A-arm (Front) 14 inch 
Length of A-arm (Rear) 9 inch 
Roll center Height (Front) 111mm(from ground) 
Roll Center Height (Rear) 240mm (from ground) 
Shock Absorber Hydraulic Remote Reservoir 
Center of gravity (FROM REAR 
LEFT CORNER) 
X axis- 667mm 
Y Axis-300mm 
Z Axis-217mm 
International Journal of Engineering and Advanced Technology (IJEAT) 
ISSN: 2249 – 8958, Volume-3, Issue-2, December 2013 
155 
 
 
Fig 12. Front A-arms Analysis (Von Mises stress= 3.47*106 
N/m2) 
 
Fig 13. Knuckle Analysis (Von Mises stress= 5.13* 106 N/m2) 
VII. BRAKING SYSTEM 
The methodology followed by us in designing of braking 
system is as follows. 
On the above factors we decided to install a hydraulic disc 
brake for all four tires. . 
A. Specification 
PEDAL RATIO : 6:1 
PEDAL EFFORT : 75lbs 
MASTER CYLINDER BORE : ¾” 
CALLIPER BORE SIZE : 0.12’’ 
TIRE SIZE : 21’’ 
ROTOR SIZE : 9.5’’ 
B. Calculation 
Braking torque (front) : 8278.76N 
Braking torque (rear) : 17857.83N 
Stopping distance : 11.19M 
Frictional force (front) : 31.04N 
Frictional force (rear) : 66.95N 
Vertical forces : 280N 
 
C. Braking layout 
 
Fig 14. Braking layout 
D. Analysis 
 
Fig 15. Braket (Von mises stress= 38.8 MPa) 
CONSIDE
RATION 
PRIORITY REASON 
Simplicity Essential This is a main goal of the team 
 
Light 
Weight 
Essential To minimize the sprung 
weight 
Shock 
Absorbing 
Essential Frontal impacts cause a heavy 
amount of damage to the car 
 
Side Impact Desired Must be able to handle uneven 
impacts from all directions 
 
Compatibili
ty with 
Steering 
High The suspension geometry 
determines the geometry of 
the steering 
Wheel 
Alignment 
Parameters 
High Reduce tire wear and ensure 
that vehicle travel is straight 
and true 
S.NO CONSIDERATION PRIORITY 
1 WEIGHT OF THE 
VEHICLE 
MINIMUM 
2 COST OF THE 
VECHICLE 
MINIMUM 
3 BRAKING TORQUE HIGH 
4 CLAMPING FORCE HIGH 
5 THERMAL 
CAPACITY 
HIGH 
6 AVAILABILITY EASILY 
AVAILABLE 
 
Design & Analysis of an All-Terrain Vehicle (ATV) 
156 
 
Fig 16. Pedal (Von mises stress= 78.19 MPa) 
VIII. STEERING 
Consideration Priority Reason 
Simple design High Easy to repair 
Light Weight Essential 
Minimize weight to 
maximize power to 
weight ratio 
Low Steering 
Ratio Essential 
Quick Steering 
response 
Ackerman 
Geometry High 
Reduction in tread 
wear of wheel 
Less turning 
radius High 
Consumes less time 
& take lesser space 
On above criterion we selected Manual Rack & pinion 
system. 
Design Specification 
 
Terminologies Approximate Values 
Turning Radius 11 Feet 
Steering Axis Inclination 8’’ 
Front Steering ratio 17:1 
Scrub radius 76 mm 
IX. TRANSMISSION 
Engine mounting : Tranverse 
Engine coupling : Key coupling 
 
 
Fig 17. Drive Train Specification 
 
Gear 
Ratio 
Torque 
(N-m) R.P.M 
Vehicle 
Speed 
(km/hr) 
Tracti
ve 
Effort(N) 
4.6 86.25 825.944 12.1638 2208.226 
2.733 51.1875 1391.702 20.4959 1311.9744 
1.67 31.3125 2275.057 33.5052 808.6821 
1.115 20.906 3407.526 50.1827 535.2548 
8.05 
(Reverse) 151.125 471.383 3.9671 6779.2227 
 
 
There are number of forces acting on the body of the 
vehicle that have to be overcome: 
• FRo = Rolling resistance= fmg = 38.4552 N 
• FCl = Climbing resistance = mg sin β = 1765.609 N (β = 
40 maximum) 
• FAe = Aerodynamics = 0.5 ρcA (v)2 = 403.48 N 
 
Ftot = Total Resistance = FRo + FAe + FCl = 2017.4252 N 
 
 
X. CONCLUSION 
The chosen design was the safest & the most reliable car for 
any long terrain. All the parameters like Safety, Cost, 
Reliability, Performance, Durability, aesthetics, Standard 
dimensions & material were also taken in consideration on the 
same time. Where ever possible finite element analysis was 
done on the regularly loaded parts & modifications were done 
accordingly to avoid any type of design failure. In case of 
rolling front curved members and rear curved members 
(Behind the driver’s seat) take the side load equally not like in 
other designs where only the rear curved members were made 
to bear the side rolling loads. 
International Journal of Engineering and Advanced Technology (IJEAT) 
ISSN: 2249 – 8958, Volume-3, Issue-2, December 2013 
157 
 
APPENDIXFig18. Whole assembly of an ATV 
 
Fig 19. Sitting arrangement of driver with optimum viewing 
angle 
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