Team Members: Brant Kochsiek BSAC Steve Pauls Team Leader Tim Rand Communicator Brian Schwartz BWIG.
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Transcript of Team Members: Brant Kochsiek BSAC Steve Pauls Team Leader Tim Rand Communicator Brian Schwartz BWIG.
Team Members:Team Members:
Brant Kochsiek BSACBrant Kochsiek BSAC
Steve Pauls Team LeaderSteve Pauls Team Leader
Tim Rand CommunicatorTim Rand Communicator
Brian SchwartzBrian Schwartz BWIGBWIG
Client:Client:
David Beebe, Ph. DDavid Beebe, Ph. D
Biomedical EngineeringBiomedical Engineering
Advisor:Advisor:
Naomi Chesler, Ph. DNaomi Chesler, Ph. D
Biomedical EngineeringBiomedical Engineering
AbstractAbstract
Many running injuries are caused by continued use Many running injuries are caused by continued use of improper or worn running shoes. The increase in of improper or worn running shoes. The increase in incidence of injury can be directly correlated to the incidence of injury can be directly correlated to the degradation of the materials used in shoe sole degradation of the materials used in shoe sole construction. The degree to which a shoe sole construction. The degree to which a shoe sole degrades is directly related to the changing degrades is directly related to the changing elasticity of the material. Two different methods are elasticity of the material. Two different methods are proposed to measure elasticity in a shoe sole. proposed to measure elasticity in a shoe sole. Strain gauges and Flexi-Force piezoelectric force Strain gauges and Flexi-Force piezoelectric force sensor devices have been added to an integrated sensor devices have been added to an integrated circuit that will indirectly measure shoe sole circuit that will indirectly measure shoe sole elasticity. Once calibrated, each circuit will have a elasticity. Once calibrated, each circuit will have a diode that lights when a shoe sole is worn past its diode that lights when a shoe sole is worn past its useful life.useful life.
Problem MotivationProblem MotivationRunning shoes last Running shoes last 300-500 miles 300-500 miles
Worn shoes do not Worn shoes do not always appear wornalways appear worn
Incidence of injury Incidence of injury increases with worn increases with worn shoesshoes
http://members.cox.net/gumpisms/hanks1.jpg
Client RequirementsClient Requirements
Design a device that:Design a device that:– Measures shoe sole elasticityMeasures shoe sole elasticity– Fits ergonomically into the shoe soleFits ergonomically into the shoe sole– Is lightweight and small so as to not hinder Is lightweight and small so as to not hinder
performanceperformance– Operable for the life of a running shoe (300-Operable for the life of a running shoe (300-
500 miles)500 miles)– Has a clear indicator so the runner will know Has a clear indicator so the runner will know
when the shoe is sufficiently wornwhen the shoe is sufficiently worn
Shoe MaterialsShoe Materials
Ethylene Vinyl Acetate (EVA)Ethylene Vinyl Acetate (EVA)
Polyurethane (PU)Polyurethane (PU)
Outsole
Midsole
Upper
Footbridge
http://www.dummies.com/WileyCDA/DummiesArticle/id-450,subcat-SPORTS.html
Nominal Running StyleNominal Running Style
• Heel strike
• Inward pronation (rolling action of the foot)
• Ball of foot strike
• Forefoot push off
http://www.dummies.com/WileyCDA/DummiesArticle/id-450,subcat-SPORTS.html
Pressure Distribution while RunningPressure Distribution while Running
Maximum pressures in the midsole occur beneath the heel, the middle to inner portion of the forefoot, and the big toe.
http://www.uni-essen.de/~qpd800/index.html
Comparator/LEDComparator/LED
Differential AmplifierDifferential Amplifier
Drive CircuitDrive Circuit
Voltage regulatorVoltage regulator
Force Sensor CircuitForce Sensor Circuit
FlexiForce® SensorsFlexiForce® Sensors
Comparison of forces Comparison of forces from top to bottomfrom top to bottom
http://www.tekscan.com/flexiforce/flexiforce.html
http://www.btinternet.com/~bury_rd/cheatah.jpg
Strain Gauge CircuitStrain Gauge Circuit
Comparator/LEDComparator/LED
Differential AmplifierDifferential Amplifier
Strain GaugeStrain Gauge
Strain GaugeStrain GaugeConstant Poisson’s Constant Poisson’s Ratio (Ratio (v)v), ,
Stress-Strain (Stress-Strain (δδ--εε)) for for Elasticity (E)Elasticity (E)
http://www.btinternet.com/~bury_rd/cheatah.jpg
www.sensorland.com/ HowPage002.html
Variable Force Variable Force SensorsSensors
Strain GaugeStrain Gauge
CostCost 33 44
Measurement Measurement accuracyaccuracy
55 33
DurabilityDurability 33 33
Circuit Circuit integrationintegration
22 33
SizeSize 33 33
PerformancePerformance ?? ??
TotalTotal 1616 1616
1 = Worst 5 = Best
AdvantageAdvantage DisadvantageDisadvantage
FlexiForce®FlexiForce®
Force Force comparisoncomparison
-Paper thin-Paper thin
-Allows for fine -Allows for fine adjustmentsadjustments
-More precise-More precise
-Complicated -Complicated constructionconstruction
-Complex -Complex comparative comparative circuitcircuit
-More expensive-More expensive
Strain Gauge Strain Gauge MeasurementMeasurement
-Cost-Cost
-Simple circuit-Simple circuit
-Simple -Simple constructionconstruction
-More of an -More of an indirect indirect measurementmeasurement
-More bulky-More bulky
Preliminary TestingPreliminary TestingSensor response Test
0
1
2
3
4
5
6
0 200 400 600 800 1000
Load (lbs)
Vo
lta
ge
(V
)
Tested
Projected
Current StandingCurrent Standing
Preliminary tests showed flaws in our Preliminary tests showed flaws in our circuit and sensor set upcircuit and sensor set up
Circuit is being reworked and future testing Circuit is being reworked and future testing will soon followwill soon follow
Research into exact placement of sensors Research into exact placement of sensors in shoe sole is ongoingin shoe sole is ongoing
Testing ProcedureTesting Procedure
Apply static loads to sensors imbedded in Apply static loads to sensors imbedded in silicone polymersilicone polymer
Loads applied in sets of 4000 which Loads applied in sets of 4000 which correlates to about a 6 mile runcorrelates to about a 6 mile run
Following each set:Following each set:– Elasticity of material will be measuredElasticity of material will be measured– Output of circuit will be read from multimeterOutput of circuit will be read from multimeter– Output vs. elasticity will be plottedOutput vs. elasticity will be plotted
MTS Servohydraulic MachineMTS Servohydraulic Machine
We plan to use an older version of this We plan to use an older version of this machine found in the Materials Testing machine found in the Materials Testing Lab in Engineering HallLab in Engineering Hall
http://www.mts.com/menusystem.asp?DataSource=0&NodeID=1483
Future WorkFuture WorkMold strain gauge into silicon moldMold strain gauge into silicon moldTest both prototypes to simulate 500 miles of Test both prototypes to simulate 500 miles of running wearrunning wearDetermine the correlation between the output of Determine the correlation between the output of each device and elasticityeach device and elasticityDetermine shoe sole wear threshold valueDetermine shoe sole wear threshold valueIntegrate chosen device and corresponding Integrate chosen device and corresponding circuit into a shoe sole for testingcircuit into a shoe sole for testingResearch and go through necessary human Research and go through necessary human subject testing proceduressubject testing proceduresUndergo human testing of the prototype shoeUndergo human testing of the prototype shoePossible patent applicationPossible patent application
ReferencesReferences““1000 Hz High-Cycle Fatigue Testing Systems.” 1000 Hz High-Cycle Fatigue Testing Systems.” MTS Inc. MTS Inc. Accessed 4/28/04 URL: Accessed 4/28/04 URL: http://www.mts.com/menusystem.asp?DataSource=0&NodeID=1483http://www.mts.com/menusystem.asp?DataSource=0&NodeID=1483““Anatomy of a Running Shoe.” Anatomy of a Running Shoe.” American Running AssociationAmerican Running Association. .
Accessed: 04/26/04 URL: Accessed: 04/26/04 URL: http://http://www.americanrunning.org/displayindustryarticle.comwww.americanrunning.org/displayindustryarticle.com..
““Biomechanics Laboratory.” Accessed: 04/24/04 URL: Biomechanics Laboratory.” Accessed: 04/24/04 URL: http://www.uni-essen.de/~qpd800/index.html.http://www.uni-essen.de/~qpd800/index.html. ““BTopenworld”. Accessed: 04/24/04 URL: BTopenworld”. Accessed: 04/24/04 URL:
http://www.btinternet.com/~bury_rd/cheatah.jpg.“FlexiForce Force Sensors.” Tekscan. Accessed: 04/25/04 URL:
http://www.tekscan.com/flexiforce/flexiforce.html.“Forrest Gump Pictures.” Cox Members High Speed Internet. Accessed 02/26/04 URL: http://members.cox.net/gumpisms/hanks1.jpgHennig, E. M., & Milani, T. L. 1995. In-shoe Pressure Distribution for
Running in Various Types of Footwear. Human Kinetics Publishers Inc., New York.
Mills, N., & Verdejo, R. 2002. Performance of EVA Foam in Running Shoes. Blackwell Inc., UK, Birmingham.
“Runner’s World.” Runners World. Accessed:04/27/04 URL: http://www.runnersworld.com/.“Running Shoes.” ePodiatry. Accessed: 04/26/04 URL:
http://www.epodiatry.com/running-shoes.htm,
Special ThanksSpecial Thanks
Professor David BeebeProfessor David BeebeProfessor Naomi CheslerProfessor Naomi Chesler
Amelia CosgroveAmelia CosgroveJohn W. DregerJohn W. Dreger
Ivar MeyvantssonIvar Meyvantsson Professor Tim OsswaldProfessor Tim Osswald
Professor Mitch TylerProfessor Mitch TylerPaul VictoreyPaul Victorey
Professor John WebsterProfessor John Webster