1. Virtual BAJA SAEINDIA 2014
Team Name Piranha Racing
Team ID 14127
Maharashtra Institute of Technology,
Pune
Wheel base 58”
Wheel Track 50”
Vehicle Height 1.58m
Height of C.G. 22”
Ground Clearance 13”
Roll Cage Material
O.D.
Thickness
AISI 4130
1.125”
0.095”
Total Length of Pipe 39.23m
Weld Length 3.45m
2. Roll Cage - Analysis
Front Impact
Stress:
216.6MPa
Side Impact
Pre Stress:
446.2MPa
Side Impact
Post Stress:
365.1MPa
Roll Analysis
Stress:
64.67MPa
Torsional
Stress:
156.6MPa
Rear Impact
Stress:
171.7MPa
3. CVT- Polaris P85 Belt CVT
Reduction
Gear Drive:
Compound Planetary Differential
• Epicyclic gear train is
used as differential with
no speed reduction.
• Fixed – Ring gear
• Input – Flange
• Output 1 – Sun 1
• Output 2 – Sun 2
ω(out) = ω(in) x 7
Reverse
Gear
Train
CVT
Input
Differential
CVT ratio=R1/R2
0.78 3.84
Shaft
• Self-designed
• Material: 16Mn5Cr4
Dia=22 mm
Transmission
CVT Output
R2=115 mm
Engine Input
R1=95 mm
• Gear Ratio = 7
• Works as FNR
Kings KT 102 Traction
Dimension(mm): 22x8x10
Wheel
5. PARAMETER FRONT REAR
Suspension Type
Double
Wishbone
McPherson
Strut
Natural Frequency 2.23 Hz 2.29 Hz
Stiffness 11.8 N/mm 32.38 N/mm
Damping Ratio 0.35 0.35
Wishbone Material AISI 4130 AISI 4130
Max. Suspension Travel 127 mm 74 mm
Transmissibility Ratio < 2.5
Spring Material
SUP 7C
Steel
SUP 7C
Steel
Toppling Speed
(at min. turning radius)
20.3 kmph
Roll Gradient 5.19 deg/g
Sprung Mass 300 Kg
Un-sprung Mass 50 Kg
Pitch Frequency 1.79 Hz
Bounce Frequency 1.64 Hz
Camber Angle Variation -2.80 – 30
Suspension
CAMBER
ANGLE
VARIATION
SUSPENSION
GRAPHS
7. Steering
Ackerman Steering Geometry
(Rack & Pinion System)
Wheel Base (L) 58”
Pivot to Pivot distance (t) 42”
Kingpin Inclination 7⁰
Caster Angle 3⁰
Camber Angle
0⁰ to 0.5⁰
(+ve)
Toe Angle 0⁰
Scrub Radius 24 mm
Steering Arm Length 120 mm
Rack & Pinion
Steering Ratio 8:1
Rack Travel
(lock to lock)
4.25”
Steering Wheel Diameter 14”
Extreme
Turning Angle
Inside 35⁰
Outside 23.57⁰
Steer Angle Error (max) 2⁰
Minimum Turning Radius 2.77m
Characteristic Speed 77kmph
Parameter Value
Length of Tie
Rod
12.97”
Assumed O.D. 15mm
Calculated I.D. 12.82mm
Material AISI 1026
0
10
20
30
40
0 20 40 60 80
Y
a
w
G
a
i
n
Velocity (kmph)
Yaw Gain v/s Velocity
0
5
10
15
20
25
30
35
0 20 40 60 80
S
t
e
e
r
A
n
g
l
e Velocity (Kmph)
Steer angle v/s
Velocity
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
10 20 30 40 50 60
Lateral Acceleration
Gain v/s Velocity
8. Disc and
Caliper
assembly
Brakes
• Hydraulically actuated disc brakes on all wheels.
• Two different pedal designs (offering left/right foot flexibility).
• 200mm petal discs (SS304) with floating caliper.
Pedal and
Master
Cylinder
assembly
Part Specifications
Master Cylinder M800 (Bosch) Bore 19.05 mm
Hose STD 3/16”
Caliper
Apache 150 &
Suzuki GS
2 POT
Bore 26 mm
Disc
TVS Apache RTR
180 Rear Disk
200 mm OD
120 mm ID
Performance Parameters Value
Perception Distance 16.66 m
Total Braking Force 1024 N
Deceleration 8.812 m/s2
Stopping Distance (60kmph) 13.4 m
Max. Dynamic wt. Front Axle 2200 N
Min. Dynamic wt. Rear Axle 1233.61 N
% Weight transfer 34 %
Bias Ratio (Front : Rear) 16 : 9
Design
Parameters
Value
Pedal Force 100 N
Leverage
(Pedal Ratio)
6:1
Piston Ratio 3.75
Braking Torque
(per wheel)
71.9 Nm
Proportioning
valves
TMC
9. Innovation
Event
Desired
Sensitivity
Pedal rotation
for Max Accn
(X)
Ra
(KΩ)
Ra=R1+Rp
Rb
(KΩ)
C
(μF)
R1 Rp 00 X0
Acceleration High 120 4.0 4.0 4.0 8.0 76 – 72 0.361
Endurance Medium 180 6.0 6.0 6.0 12.0 114 – 108 0.241
Maneuverability Low 240 8.0 8.0 8.0 16.0 152 – 144 0.180
Rack &
Pinion
Accelerator
Pedal
Electronic Throttle Control System
Max.
Pedal
Travel=
300
300
IC 7806
12. Component Potential Failure Mode
Potential
Causes/
Mechanism of
Failure
Potential Effects of
Failure
O S D RPN Recommended Action
• Gearbox
Provides
variable
torque and
speed to
lower power
train.
• Enables
effective
conversion
of engine
power
according to
variable
loads
Surface
Wear
Abrasive
Wear
Foreign particles
in lubricant
Lapped finish; radial
scratch marks;
grooves on contacting
surfaces
1 6 7 42
Oil filters; high viscosity oils;
gear enclosure; regular
replacement of oil; increase in
surface hardness
Corrosive
Wear
Chemical action
of active
ingredients in
lubricant
Fine uniform wear 1 6 7 42
Proper selection of lubricant;
regular check-up and
replacement of oil
Initial Pitting
Tooth profile
errors; surface
irregularity;
misalignment
Redistribution of loads
due to progressive
removal of high
contact spots
1 7 4 28
Precise machining and
alignment;
Destructive
Pitting
Loads > surface
endurance
strength of
material
Complete destruction
of tooth surface and
premature breaking
3 8 3 72
Design gears for wear strength
> (static + dynamic) loads;
increase surface hardness
Scoring
Overheating due
to excessive
frictional heat
Alternate welding and
shearing
2 6 4 48
Adjusting surface parameters to
reduce working temp.; proper air
and lubricant circulation
Breakage
Fatigue
Failure
Root stress >
endurance limit of
material
Fretting and breach
marks; breakage of
part or whole tooth
2 8 2 32
Design for reduced stresses;
polishing and shot-peening of
root fillet
Overload
Breakage
Sudden overloads
> tensile strength
of material
Stringy fibrous break
(pulled or torn apart
abruptly)
2 8 2 32
Design with greater factor of
safety, and higher value of
service factor.
DFMEA