team hpv: review - florida institute of technologymy.fit.edu/~dkirk/4291/team page/mid term...

Team Human Powered VehicleTeam Human Powered Vehicle

This document is controlled information and is only reproducible with permission of Team HPV 1

Team HPV: A Quick Review

Prepared By:

Tyler Jandreau, Taylor Brown, Jamie Huffman, Joey Stine, Kevin Villa, Matt Strand, Kyle Chapman, Jimmy Woodard,

Adam Cooper



To Design and Build one of These:

Overall Goal


This document is controlled information and is only reproducible with permission of

Team HPV3

Objectives

“ Team HPV will design and build an aerodynamically and mechanically efficient vehicle that uses pure human power to achieve a top speed of at

least 61.5 mph.”

Presents a Unique Challenge:

• Rider Watt Feasibility Calculations• Aerodynamic Considerations• Frame Analysis and Design• Shell Analysis and Design• Drivetrain Analysis and Design• Fabrication of all necessary “not‐off‐the‐shelf” parts



Evolution of Requirements

To determine the validity of the requirements, we must first understand needs of product:

Crash Preparedness?

Fabrication Process?

Correct Velocity?

Testing?

Time constraint?



Functional Requirements

To determine the success or failure of the HPV project, it is necessary to determine what the HPV has to actually do:

• HPV has to be completed before Senior Showcase, 2009

• HPV has to be rideable

• HPV has to have basic rider safety features

• HPV must be light enough for one rider to propel

• HPV shell must be puncture resistant and resist a specific point load

• HPV drive train must not have a mechanical loss of more than 5% of total input to reduce frictional losses



Team Goals

The HPV team’s goals include:

Team HPV will assemble and build a vehicle to compete in land speed challenge

Team HPV will perform all necessary calculations for success by hand

Computer tools will be used to verify previously completed hand‐calculations

Success will be met by meeting 100% of functional requirements and ~80% of non‐functional requirements



Team HPV7

Basic Systems Engineering

Introduction of Basic Flow Chart

• Literature Review helps team create revolutionary ideas

• Literature Review also eliminates exploring “dead ends”

• Design and Analysis obviously lends itself to Prototyping



Calculations

δ = Fa2(3L - 4a)/6EI

The equations to the left were used to perform basic feasibility of the HPV to determine if the human body can break the 61.5 mph barrier

The equation to the right was used for analysis on the frame. It is the equation for deflection of a beam with two free ends and a force in the middle. Also, standard deflection was used with one ridged end.

δ = FL3/3EI

wright.nasa.gov/airplane/drageq.html

Team Human Powered Vehicle

This document is controlled information and is only reproducable with permission of

Team HPV9

•Impulse from the high watts has little effect on overall change in velocity while long, slow burns have a significant change in velocity. This also shows that if vehicle is lighter, it will have greater change in velocity.

Power Feasibility


10

Rider/Watt Feasibility

Obtaining the Human Power Curve

• Trained Humans only 25% Efficient

• Watt Output Decreases Rapidly

• Ergonomic Position Greatly Effects Watt Output

• Cycling “Envelope” can be Calculated from these Parameters


Team HPV



Team HPV11


Distance in Miles

Velocity in

MPH

OUR GOAL

Plotted with a CdA of 0.2. Ours can afford to be higher than this.

It is substantially more difficult to accelerate at already high velocities

Graphical Power Envelope:



Team HPV12


Creating a Cycling “Envelope”.

MPH Watts

CdA = 0.25 (our vehicle)

MPH Watts

CdA = 2.4 (road cyclist)

It is clear that a small aerodynamic increase will yield the speeds we need



Drivetrain Calculations

Feasibility calculations for drivetrain system were also preformed, showing HPV team that a minimum loss of power can be achieved with proper engineering:

Drivetrain must be able to meet or exceed 8.4:1 Ratio. Most ideally, 9:1

Calculations and analysis of CVT transmission showed that 8:1 is nearly impossible for standard CVT transmissions (~4:1). We needed to double this.

To obtain 9:1, manual production of a CVT must be facilitated, which exceeds groups ability in machine shop.

Hybrid drive train system developed, using half belt, half chain mechanisms for power transfer



Team HPV14

700x23mm Series Wheels

Dia (in) Md‐Drv RatioCrank Pulley 3.5001.750 Unit ConversionMid Drive Pulley 2.000 12.781

# of Teeth Ratio Overall Ratio Speed (mph)Chain Ring 53.000Cassette 1 34.000 1.559 2.728 21.344 10.672<‐Min Start speed

2 24.000 2.208 3.865 30.237 18.445<‐ Optimal Overlap3 21.000 2.524 4.417 34.557 37.566 <‐ 88 rpm at same above speed4 17.000 3.118 5.456 42.6885 15.000 3.533 6.183 48.3806 13.000 4.077 7.135 55.8237 11.000 4.818 8.432 65.972

Wheel Dia (in) 26.300Wheel Rad (in) 13.150Circumference (in) 82.624



700x23 Race Wheel

2" Mid Drive Pulley

53 Tooth Chain Ring

INPUT3" Pulley w/

Cranks

Belt Bike Chain

700x23 Race Wheel

Cassette34‐21‐17‐15‐13‐11‐9T

INPUT3" Pulley w/

Cranks

Belt Bike Chain

•Speed calculations using mid‐drive and possible cassette option.



Team HPV15

•Validity testing using standard road bike to ensure accuracy of calculations.

Tests performed on Jimmy’s road bike.

Calculation Validity TESTING 700x23mm Series Wheels

NO MID DRIVEUnit Conversion

12.781

Theoretical Experimental# of Chain Ring Teeth # of Cassette TeethRatio Cadence (Rpm) Speed (Mph) Speed (Mph) % Diff. (%)

39 15 2.600 44 8.951 9.0 4.90789311539 23 1.696 75 9.950 10.0 4.96183770239 23 1.696 95 12.604 12.6 0.38167224539 23 1.696 115 15.257 15.2 5.72518219153 23 2.304 75 13.522 13.6 7.768651236

Wheel Dia (in) 26.300Wheel Rad (in) 13.150Circumference (in) 82.624




Picture taken on 9/1/2008 in Jimmy’s Garage.

First Mock Up

Mock up with 53 tooth chain ring and standard bike cassette/derailleur

Test runs indicate > 61 mph

This confirms initial drivetrain calculations.



•Hybrid belt and chain drive system to minimize losses.


First Mock Up

700x23c series wheels at 100 cadence requires a total gear ratio of 8.4:1.



Team HPV18

The incredible torque from the belt made our wood model unstable.

Further testing required an aluminum/steel frame


Drivetrain

MAX STRESS



Team HPV19

Video of First Mock Up

This video details the base level prototype testing.



Team HPV20

Frame

Team Human Power will be designing and building two frames:

1. Aluminum Frame• Easy to Build• Use as Testing Mule• Practice Operating

2. Composite Frame• Lighter• Stronger• Integral Piece of Shell• More Torsional Rigidity



Team HPV21

Frame

Aluminum test frame to be used for practice and calculation purposes.

Not a Wine Bottle



Team HPV22

Frame

Frame Considerations

• Stability• Rider Ergonomics• Strength• Torsion Rigidity• Weight

Max Tension 1.88 kipMax Compression .56 kipMax Shear 1.88 kipMax Moment 28.4 ft*kip

Basic Force Directions


Internal Normal Forces

-1000

-500

0

500

1000

1500

2000

2500

0 10 20 30 40 50 60 70

Norm

al F

orce

, lb

Internal Moments

-35000-30000-25000-20000-15000-10000-5000

05000

1000015000

0 10 20 30 40 50 60 70

Mom

ent,

ft*lb

,0∑ =xF ∑ = ,0yF ∑ = 0nF

∑ = 0vF∑ = 0xM

Internal Shear Forces

0200400600800

100012001400160018002000

0 10 20 30 40 50 60 70

She

ar F

orce

, lb



Team HPV23

Frame



Team HPV24

Frame

Both ANSYS and Hand Calculations were done on the Aluminum Frame

This technique ensures accuracy through redundancy



Team HPV25

Frame

Weight of Beam at Given Core Thickness to Resist Internal Forces

(Carbon-epoxy T300/N5208)

0

20

40

60

80

100

0 2 4 6 8

Core Thickness, in

Bea

m W

eigh

t, lb

HRH-10Al 1/8-5052-.001Al ACG-1HRH-49-1/4

bhtM

=σ

bhV

c =τ



Team HPV26

Frame

Findings

•Greatest internal forces between seat mount and front fork

•Greatest moment between front fork and pedals

•Sandwich core greatly reduces weight required

Future Tasks

•More research in material selection

•Optimize local ply thickness

•Finalize design to use shell structurally



Team HPV27

Loss System % Total Power Loss

Aerodynamic Drag 85‐90%

Rolling Resistance 5‐10%

Drivetrain Friction Loss ~1‐2%

Wheel Rotation Power ~1%

Miscellaneous Loss

Power to Overcome Gravity (Hill Application)

Varies Greatly Depending on % Grade of Hill

Power Loss for HPV by Percentage.

Shell Considerations



Team HPV28

•This shows relation between frontal area, Cd, and power required to travel 61.5mph.

Shell Feasability

Power Available: 1200 W

A = 0.45 or 0.3Cd = 0.2 or 0.3



Team HPV29

Shell Designs

CdAof 2.4

CdAof 0.6

CdAof 0.25

http://www.adventuresofgreg.com/HPVlog/VehicleDrags.html

Bad Good



Team HPV30

Shell

Foam Donation

Used to make multiple shell models

Will be tested in wind tunnel

Model with lowest CdA value will be modeled in Pro|E



Team HPV31

Shell

Reverse EngineeringWhy Reinvent the Wheel?

Testing and improving on previous designs increase efficiency.Much easier to determine what worked and what didn’t.

NO

YES



Team HPV32

Shell

What Will it Look Like?Fast

NO



Team HPV33

Auxiliary Systems

What are Auxiliary Systems?Secondary systems that fulfill necessary functional requirements:

• Braking• Cooling

NO

• Turning• Saftey



Team HPV34

•Shows Kinetic energy associated with different weights and speeds•Will be used for braking distance calculations

Braking Feasability



Team HPV35

Current Budget

Total Budget = ‐ $62



Team HPV36

Current Sponsors

At this time, our sponsors are as follow:



Team HPV37

Timeline

March April May June July Aug Sept Oct Nov Dec Jan Feb March April MayJimmy ConditioningFundraising

Assemble Sponsorship PackageBrainstorm Potential Businesses

FrameDesignRe-Design

Pro|Engineer

Determine MaterialsAnsys

ManufactureShell

Design

Pro|EngineerDetermine MaterialsCFD

ManufactureDrivetrain

Design

ManufactureBuild Final HPVTestPresent Final Results



Team HPV38

References

http://www.speed101.com/image_speedbike.htm

http://tingilinde.typepad.com/photos/uncategorized/trike_1.jpg

http://www.adventuresofgreg.com/HPVMain.html

http://www.speed101.com/image_speedbike.htm

http://tingilinde.typepad.com/photos/uncategorized/trike_1.jpg



Team HPV39

Questions?

team hpv: review - florida institute of technologymy.fit.edu/~dkirk/4291/team page/mid term...

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