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Virtual BAJA SAEINDIA 2014
Team Name Piranha RacingTeam 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 MaterialO.D.
Thickness
AISI 41301.125”0.095”
Total Length of Pipe 39.23m
Weld Length 3.45m
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
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 OutputR2=115 mm
Engine InputR1=95 mm
• Gear Ratio = 7• Works as FNR
Kings KT 102 TractionDimension(mm): 22x8x10
Wheel
7.5511.03
13.6014.82
17.1120.22
24.7131.77
40.0060.00
0.000
0.400
0.800
1.200
1.600
ACCELERATION v/s ROAD SPEED
Engine(rpm)
Power(w)
GearRatio
Traction (N)
Air Drag(N)
Inertia(N)
Velocity(m/s)
Acceleration(m/s2)
Gradability
2000 3730.00 25.08857 1600 1.650798193 1045.436 7.55325 1.485838009 31.85770558
2400 4699.80 23.89388 1600 2.620807212 986.9174 9.517095 1.572957555 31.83547437
2800 5445.80 24.05753 1600 3.518841429 994.765 11.027745 1.55964594 31.81489748
3200 6117.20 24.47666 1600 4.439986821 1015.107 12.38733 1.527484809 31.79379581
3600 6714.00 25.08857 1600 5.348586146 1045.436 13.59585 1.482300934 31.77298626
3800 6863.20 25.90668 1600 5.588942363 1087.156 13.89798 1.425196698 31.76748219
3800 6863.20 21.04918 1300 8.466090207 859.0678 17.105206 1.451030902 25.05948271
3800 6863.20 17.81084 1100 11.82453922 733.2261 20.215244 1.422720129 20.76034664
3800 6863.20 14.57251 900 17.66381784 628.3579 24.70752 1.332578354 16.53003386
3800 6863.20 9.715004 600 39.74359014 510.3813 37.06128 1.009551889 10.08323425
3800 6863.20 8.095837 500 57.2307698 481.5426 44.473536 0.826031286 7.767741583
3800 6863.20 6.667602 411.792 104.1666667 460.4569 60 0.57035811 5.119730408
0200400600800
10001200140016001800
AIR DRAG (N)
TRACTION VS VELOCITY
INERTIA
ROLLING RE-SISTANCE
FORCES v/s VELOCITY0
5001000150020002500300035004000
ENGINE RPM v/s VELOCITY
ENGINE (RPM)
Transmission
Briggs & Stratton Model 20 Specifications:
Displacement 305 cm3
Bore x stroke 79.25 mm x 61.93 mm
Compression Ratio 8:1
Max. Power 7.5 kW @ 4000 rpm
Max. Torque 25.18 Nm @ 2200 rpm
PARAMETER FRONT REAR
Suspension TypeDouble
WishboneMcPherson
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 MaterialSUP 7C
SteelSUP 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
CAMBERANGLE
VARIATION
SUSPENSION GRAPHS
FEA of Critical Components
Wheel Assembly
Wheel Assembly exploded
view
Steering
Ackerman Steering Geometry (Rack & Pinion System)
Wheel Base (L) 58”
Pivot to Pivot distance (t) 42”
Kingpin Inclination 7⁰
Caster Angle 3⁰
Camber Angle0 to 0.5 ⁰ ⁰
(+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 50 60 7005
10152025303540
Yaw Gain v/s Velocity
Velocity (kmph)
Yaw Gain
0 10 20 30 40 50 60 7005
101520253035
Steer angle v/s Veloc-ity
Velocity (Kmph)
Steer Angle
10 20 30 40 50 600
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
Lateral Acceleration Gain v/s Velocity
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”
CaliperApache 150 &
Suzuki GS 2 POT
Bore 26 mm
DiscTVS Apache RTR
180 Rear Disk200 mm OD120 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
Innovation
EventDesired
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 SystemMax. Pedal Travel=300
300
IC 7806
Ergonomics & Electrical
Hand Reach EnvelopeVision Cone
Reach Limit &
Visibility
Infrared Emitter Infrared Sensor
Safety
ABC Grade 0.5 kg Fire extinguisher
INFRARED EMITTER
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 42Proper 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 28Precise machining and alignment;
Destructive Pitting
Loads > surface endurance strength of material
Complete destruction of tooth surface and premature breaking
3 8 3 72Design gears for wear strength > (static + dynamic) loads; increase surface hardness
ScoringOverheating due to excessive frictional heat
Alternate welding and shearing
2 6 4 48Adjusting 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 32Design 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 32Design with greater factor of safety, and higher value of service factor.
DFMEA
Project Plan & Team Distribution
Team
Dis
trib
ution
(25)
Steering 1BE, 2TE
Suspension 2TE
Transmission 2BE, 2TE
CAD/CAE 1BE
Brakes 1BE, 1TE
Electrical 2SE
Innovation 3SE
Cat-Con 1BE, 1SE
Marketing/Project Planning 2SE
Aesthetics/Ergonomics
2SE
Safety 2SE
Workshop Facilities & Technical Components
Facilities Technical Components Quantity Unit Cost (INR) Total Cost (INR)
Engine 1 20000 20000
Gear Box 1 20000 20000
CVT 1 80000 80000
Steering Rack 1 7000 7000
Hub 4 5000 20000
Knuckle 4 6000 24000
Brake Calliper 4 2500 10000
Brake Disc 4 500 2000
Shafts 2 2700 5400
Shock Absorbers 4 4500 18000
Battery 1 3000 3000
Kill Switches 2 2000 4000
Steering Column 1 1800 1800
Servo Motor 1 2800 2800
Grand Total = 218000
• Weight of Vehicle with Driver: 350 Kgs• Finance Budget: INR 3.5 Lakh
Design Validation
Camber Angle Variation v/s Wheel Travel Roll Centre Height v/s Wheel Travel
Half Car Model
Thanks
Vehicle completion Date:18 January 2014
Vehicle Inspection Date: 22 January 2014
Our Sponsor
M.I.T. Pune
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