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Project Overview• Primary Goal–Design and build a working electric
vehicle
• Accelerated design cycle–Modification of previous designs
Project Overview• 1st electric vehicle for Ram Racing– Create the platform for future years of Ram Racing
to iterate on
• Integration of electrical and mechanical engineers– Adds expertise of electrical systems which will
allow addition of more complex systems like:• Regenerative braking • The use of high voltage systems
Background• FSAE is the largest international competition
involving engineering and automotive design• FSAE competition is comprised of 7 scored events
Static Events include:• Cost report• Design Judging• Presentation
Dynamic Events include:• Acceleration• Skidpad• Autocross• Endurance
Background• Progression of cars
2011 CSU FSAE RR112013 CSU FSAE RR13
2007 Ram Racing FSAE RR07 2012 CSU FSAE RR12
Photo courtesy: Ram Racing
Photo courtesy: Ram Racing
Photo courtesy: Ram Racing
Photo courtesy: Ram Racing
Design ConstraintsConstraint Method of Measurement Limits Driving
FactorWheelbase Length in inches: from the centerline of front to rear
tires>60in. FSAE Rule
T2.3
Track Width Width in inches: from the centerline of side to side tires
>75% front track to rear track
FSAE Rule T2.4
Power Output Kilowatts: Drawn from high voltage battery <80kW FSAE Rule EV2.2
High Voltage Battery Pack
Volts: overall voltage from any two points 300 V DC Max FSAE Rule EV1.1.2
Roll Plane Measured by tangent line between Main and Front Roll Hoops
2in, min clearance to
driver helmet
FSAE Rule T3.10.3
Suspension Inches of bounce and jounce 1in in both directions, min
FSAE Rule T6.1
Battery Pack Pack must withstand external loading 20g long. 20g lat
20g vert
FSAE Rule AF4.8.2
Safety Determined by Electrical safety officers Determined by Technical Inspectors at FSAE
For Car safety to prevent Serious injury or death
0 FSAE Rules/ Team Driven
Design ObjectivesObjective Priority
Rating5-Highest1-Lowest
Method of Measurement (Theoretical)
Method of Measurement
(Actual)
Objective Direction
Target
Battery Pack Capacity
4 Hand calculations, lap simulations
Endurance simulation at test site
increase +10% of endurance
distanceBattery Pack
Mass3 Spec Sheet with
hand calculationsScale decrease <140lbs
Compared to other FSAE EV
teams batteries
Lap times: Autocross
1 Lap simulations Vehicle testing details TBD
decrease < 1min 20sec from the Michigan 2013
track layout
Endurance Completion
5 Lap simulations 22km endurance test increase +10% of endurance
distanceLight Weight 1 Hand calculations Scale decrease <700lbs w/out
driver
Design Summary• Due to the complications of integrating an
electric drivetrain, the team has decided that getting the car done early is the biggest concern– Getting the car done earlier will allow for more
testing time– The electrical system will be tuned primarily based
off of driver feel
Final Concept
Units(Deg)
• Function– Main structure– Protects driver– Transmits loads
• Feasibility– Modeling in CAD– Installed torsional stiffness test
• DFX– Manufacture– Packaging– Safety
• Details– FEA stiffness: 998 lb-ft/deg– 17% correction factor (overestimate):
828 lb-ft/deg– Mass (est.): 90.7 lbs
• Tubes: 83.7 lbs• Filler Rod: 2 lbs• Tabs: 5lbs
Image: Ram Racing
Image: Ram Racing
Final Concept (FMEA)# Item and
FunctionPotential
Failure Mode
Potential Effect(s) of
FailureSEV Potential Cause(s)/Mechanism(s)
of Failure OCC Current Design Controls DET RPN Recommend Actions
1Chassis Primary
StructureWeld Failure
Disabled Vehicle,
Driver Injury, Loss of Control
10 Bad Weld Quality 6 Visual Inspection 4 240 100% Inspect All
Chassis Welds
2Chassis
Secondary Structure
Motor Support Failure
Driver Injury, Damage to
other systems
10 Bad Weld Quality, Incorrect Geometry 6 Visual
Inspection 4 240 100% Inspect All Chassis Welds
3Chassis Primary
StructureTube Failure
Loss of Stiffness,
Damage to Other
Systems
6 Undersize Wall Thickness in Tube 4
Manufacturer Certifications,
Visual Inspection
7 168100% Inpsect all
Chassis Tubes Before Welding
4Chassis
Secondary Structure
Tab Failure
Damage to Other
Systems, Loss of Control
7 Bad Weld Quality, Incorrect Geometry 6 Visual
Inspection 4 168 100% Inspect All Chassis Welds
5Chassis Tertiary
Structure
Battery Support Failure
Driver Injury, Diasbled Vehicle
10 Bad Weld Quality, Improper Support 2
Visual Inspection,
Manufacturer Certifications,
Additional Battery
Containment
5 100 100% Inspect All Chassis Welds
Final Concept (Budget)Chassis Budget Cost Source Donation?
Chassis Tubes and Profiling $2,900 Cartesian VR3 No
Remachining Fixture Plates $500 Woodward Yes
Fixturing Stock $400 McMaster No
Fasteners $100 Suburban Bolt No
Welding Filler $100 Arc-Zone No
Tab Stock $100 Online Metals No
Total: $6,600
Cost After Donations: $3,600
Final Concept• Function
– Keep tires in contact with pavement– Keep tires in condition for optimum
accelerations• Feasibility
– Modeling in CAD/FEA– Optimum Kinematics Analysis
• DFX– Manufacture– Reliability– Performance
• Accelerated Design Cycle– Adaptation of design features from last 3
years
Creo Solid Model Optimum K Kinematics Model
Image: Ram Racing Image: Ram Racing
Final Concept (FMEA)# Item and
FunctionPotential Failure
Mode
Potential Effect(s) of
FailureSEV
Potential Cause(s)/Mechanism(s) of
FailureOCC
Current Design
ControlsDET RPN Recommend
Actions
1Outer
Suspension Ends
Stress Concentration in Bending
Damage to other systems, Loss of control
10 Manufacturing Error 1 Visual Inspection 2 20 Inspection by
recipiant
2 Uprights Stress Concentration in Bending
Damage to other systems, Loss of control
8 Manufacturing Error 2 Visual Inspection 7 112 Inspection by
recipiant
3 Rockers Panel Delamination Damage to
other systems, Loss of control
8 Manufacturing Error 1 Visual Inspection 6 48 None
4 Carbon Tubes Buckling/Bending Damage to
other systems, Loss of control
10 Incorrect Geometry 1Pre-testing
Visual Inspection
5 50Pre and Post-
Testing Inspection
5Pull/Push Rod
Tubes & A-arm Tubes
Adhesive Failure in Shear
Damage to other systems, Loss of control
10 Improper Bonding Procedure, Insifficient Bonding Area 4 Visual
Inspection 7 280Tighter Control
of layup process
Final Concept (Budget)Suspension Budget Cost Source Donation?
Brake Discs $200 In house NoBrake Pads $75 In house No
Brake Calipers $150 In house NoBearings (spindle) $150 SKF No
Bearings (rod ends) $400 Aurora NoCarbon tubes $200 In house No
Stock $200 Metal Distributor NoTires $170 x 4 Hoosier No
Dampers $1,720 In house NoSprings $250 In house NoTotal: $9,025
Cost After Donations: $1,430
Final Concept• Function:
– Transfers Torque to rear wheels– Accelerates car
• Feasability: – Modeling in CAD– FEA analysis
• DFX:– Efficiency– Reliability– Packaging
• Details:– Torque: 210 Nm– Chain pull 6700N– 4:1 gear ratio– Up to 80% Torque bias to one wheel: 624
NM
Image: Ram Racing
Image: Ram Racing
Final Concept (FMEA)# Item and
FunctionPotential
Failure Mode
Potential Effect(s) of
FailureSEV Potential Cause(s)/Mechanism(s)
of Failure OCC Current Design Controls DET RPN Recommend
Actions
1 Half Shaft Torsional Shear
Disabled Vehicle 8 Poor design, Machining
Imperfections 4FEA, Previous
cars' Performance
9 288 FEA, Stronger Spares
2 Chain Elongation, Break
Disabled Vehicle 8 Improper Maintenance/tensioning 2 Professional
Help, Math 6 96 Spare Sprockets, Spare Chain
3 Differential Mounts
Fatigue, Bending,
Shear
Disabled Vehicle 8 Poor design, Machining
Imperfections 3 FEA 7 168Spare Mounts,
Material Evaluation
4 Motor Mounts
Fatigue, Shear
Disabled Vehicle, Driver
Injury10 Poor design, Machining
Imperfections 3 FEA 7 210Spare Mounts,
Material Evaluation
5 Motor Cooling Oil Starvation
Disabled vehicle, Motor
Failure8 Improper Flow Rate, Pump Failure 2
Specialty Pumps,
Professional Help
2 32Monitor Pumps Closely, Safety
Shutoff
Final Concept (Budget)Drivetrain Budget Cost Source Donation?
Motor $9,000.00 Remy, Inc YesDifferential $1,000.00 HPF Performance No
Inboard Tripod Carriers $370.00 RCV NoTripods $140.00 RCV No
Cooling Pumps $1,000 Meziere YesHalf Shaft Stock $300.00 Metal Distributors No
Aluminum Mount Stock $200.00 Metal Distributors NoChain $60.00 Ebay No
Sprockets $120.00 Sprocket Specialists No
Total $12,190.00
Cost After Donations $2,190.00
Final Concept• Function
-Drivetrain power• Feasibility
– Modeling in CAD– Circuit schematics
• DFX– Packaging– Safety
• Details– 72S2P battery back– 300Vdc max, 266Vdc
nom.– Capable of 375Adc
continuous– Safe under failure
– Weight: Est 104 lbs – 7.5kW hrs Image: Ram Racing
Image: Ram Racing
Final Concept (FMEA)# Item and Function Potential Failure
ModePotential Effect(s)
of Failure SEV Potential Cause(s)/Mechanism(s) of Failure OCC Current Design Controls DET RPN Recommend Actions
1 Battery Cell for energy storage Single cell failure
Higher chance of failure in parallel cell counterpart
2Neglect, exceeding rated specifications, poor cell
construction3 Battery management
system monitoring 2 12Handle with care,
operate within specifications
2
Battery Management
System for monitoring cells
Voltage, Current, or
Temperature sensing failure of 25% of cells
Fire, cell abuse, Estimation of
sensed parameters
(done automatically
by BMS)
10 Exceed lifetime, bad soldering, extreme vibration 2
Visual inspection, isolate cell boards
from vibration along with cells
7 140 Inspect all solder work
3
High voltage controller for
controlling the motor
Control system failure
Vehicle shutdown 8 Misuse/neglect 1 Care is to be taken
with the controller 2 16Handle with care,
operate within specifications
4 Battery Cell for energy storage
Two parallel cell failure
Sudden loss of all power 8
Neglect, exceeding rated specifications, poor cell
construction2 Battery management
system monitoring 2 32Handle with care,
operate within specifications
5
High voltage controller for
controlling the motor
HV cable disconnection
Driver injury, total loss of power, fire
10 Improper torque for connection 2 Check all torque
specifications 6 120Check torque
applied to connection point
Final Concept•Function
–Technical Inspection–Safety shutdown circuitry–Power various sensors
•Feasibility–Circuit schematics
simulations–Test and retest circuits for
faults•DFX
–Build/wire circuits–Safety
Image: Ram Racing
Final Concept (FMEA)# Item and
FunctionPotential
Failure Mode
Potential Effect(s) of
FailureSEV
Potential Cause(s)/Mechanism(s) of
FailureOCC Current Design
Controls DET RPN Recommend Actions
1Torque
Encoder Accelerometer
Sensor Failure Loss of Control 6 Sensor mounting error, loose wire/connections 4
Visual Inspection,
Sensor fault test3 90
Tighten connections, test with multimeter
2 Brake Encoder Brake Sensor Failure Loss of
Control, 6 Sensor mounting error, loose wire/connections 4
Visual Inspection,
Sensor fault test3 90
Tighten connections, test with multimeter
3
Arduino Mega Microcontrolle
r for low voltage controls
Programming/ Power Failure
Loss of Control, Signal error to motor
controller
6 Loose connections, lose of power 5
Visual Inspection,
Inspection of programming
code,
4 144
Tighten connections, test with multimeter, review program
for errors
4 Sensata Crash Sensor Sensor Failure
Driver Injury, due to
improper shut down of tractive system
10 Impact upon crash does not activate sensor 5
Visual Inspection,
Sensor fault test3 150
Shake the sensor to see if it opens
the circuit
5
Bender Isometer Insulation
Monitoring Device
Tractive and Grounded low voltage system desegregation/
Sensor fault
Driver Injury, Potential
shock10 No seperation between tractive
and grounded low voltage systems 6
Visual Inspection,
Manufacturer Certifications,
Sensor fault test
6 360
Check with multi-meter to see if
tractive and grounded low
voltage systems are isolated
Final Concept (Budget)Controls Budget Cost Source Donation?
HV Cables $400 Champlain Cable Yes
HV Controller $5,250Rinehart Motion
Systems No
Batteries $12,500 Melasta Part Sponser
Bus Bar $250Storm Power Components No
Batter Management System $1,624 Elithion No
Torque/Brake Encoder $229 x 3 XT Racing No
Arduino Mega 2560n M3 $28 Ardunio Yes
Misc. Components $500 Various Mix
Total $21,239
Cost After Donations $20,311
Validation Plan•Majority of parts for final assembly or testing have been ordered or are currently on hand
•Assembly ongoing through winter break
Image: Ram Racing
Image: Ram Racing
Validation Plan• Evaluation
– CAD
– Hand Calculations
– Modified Ram Racing Designs
– Road Testing
– Simulation• Safety Circuit
– Specific Component Testing• Impact Attenuator
• Battery Cell
Image: Ram Racing
Image: Ram Racing
Term II Work-Plan• Main Goals– Finish manufacturing and assembly of vehicle– Begin testing and data collection of vehicle
• Secondary Goals and Contingency –Refine and fix any design flaws–Rework on systems that fail, break, or do not
work as intended
References• [1] SAE International. (2014, September 1). 2015 Formula SAE®
Rules [Online]. Available:http://www.fsaeonline.com/content/2015-16%20FSAE%20Rules%20revision%20in%20progress%20kz%2083114.pdf