Post on 11-Feb-2017
PowerPoint Presentation
Final PresentationBy: Brendan Keane, Logan McCall, Reggie Scott, Mark SwainInstructor: Dr. Nikhil GuptaSponsor: Dr. Philip Flater (Air Force Research Laboratory Eglin AFB)Advisor: Dr. Simone HrudaTabletop Torsion Device
4/15/2015Group 13
IntroductionDesign and AnalysisPrototype TestingProject ManagementConclusionOverviewReginald Scott
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Current torsion tester at the Air Force Research Laboratory (AFRL) Munitions Directorate at Eglin AFB is approximately 5 meters in lengthSmall sample geometries result in inaccuracy and inefficiency
Introduction
Figure 2.1: Existing Torsion MachineDISTRIBUTION A: Approved for public release, distribution unlimited. (96ABW-2014-1649)Reginald Scott
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Small specimens are a result of original plate stock dimensionsSpecimens tested:Aluminum 2024Titanium 64Specimen Geometry
Original plate stockBlank removedSample machinedFigure 3.1: Specimen productionDimensionMeasurement (mm)Total Length58.4Gauge Length12.7Width14.3Inner Diameter9.09Fillet Radius27.9Grip Length20
Table 3.1: Specimen dimensionsDISTRIBUTION A: Approved for public release, distribution unlimited. (96ABW-2014-1649)Reginald Scott
Group 13Speaking: # of 27Final Presentation
4/15/2015
Maximum torque output: 100NmMachine must fit in an area (footprint) of 1m2Monotonic (one direction) free-end torsion loading Free end must allow for axial motionCompatible with measurement equipment used by AFRLBudget - $2,000
Design RequirementsReginald Scott
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Goal Statement:Design a more effective way of testing small specimens in free-end torsion
Design RequirementsReginald Scott
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DIC (Digital Image Correlation)DISTRIBUTION A: Approved for public release, distribution unlimited. (96ABW-2014-1649)Figure 6.2 Example DIC use in torsion sample
Figure 6.1 DIC setup at Eglin AFRLBrendan Keane
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Current method used by AFRL to measure applied stress:Strain gage placed on elastic barUse shear modulus relationship to output stressLoad MeasurementFigure 7.1: Stress vs. strain plot showing the shear modulus relationship
Brendan Keane
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Breakdown of Design
Brendan Keane
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Load GenerationDesignCostWeightAccuracyComplexityMaintenanceVariabilityTotalWeight Factor0.250.050.250.10.10.25(1) Crank System5315512.9(2) Hydraulic1151153(3) AC Motor3353354
(1)(2)(3)Brendan Keane
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Load ApplicationDesignCostWeightReliabilityComplexityVariabilityTotalWeight Factor0.250.150.30.10.2(1) 3-Jaw Chuck555354.8(2) 4-Jaw Chuck355313.5(3) Self-Aligning Vise313553.3(4) Collet555314
(1)(2)(3)(4)Brendan Keane
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Linear MotionDesignCostWeightDurabilityComplexityTotalWeight Factor0.40.20.20.2(1) 4 Rail Ball Bearing Guide12111.4(2) 2 Track Roller Bearing Guide35554.2(3) 2 Rail Ball Bearing Guide55334.2
(1)(2)(3)Brendan Keane
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Frame
Design Considerations:Strength Machinability WeightCostMaterial Selection:Steel
Figure 12.1: Frame design Brendan Keane
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Concept Evolution
Brendan Keane
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Figure 5.1: CAD representation of design Design Overview Logan McCall
Steel Shaft
3213
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Vendor: GraingerRpm: 18Gear ratio: 95:1Max torque: 116 NmWeight: 26 lbs
Load Generation: AC GearmotorFigure 15.1: AC Gearmotor
Logan McCall
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Vendor: Automation DirectSingle phase input, three phase outputDigital keypadForward and reverseExpandable
Motor Control: VFDVariable Frequency Drive (VFD)Figure 16.1: VFD keypad
Logan McCall
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Vendor: LittleMachineShopWeight: 6.4 lbsOuter diameter: 3.94 in (10 cm)Inner diameter: 1.02 in (2.59 cm)
Load Application: 6-Jaw ChuckFigure 17.1: 6 Jaw Chucks holding specimen
Logan McCall
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Load MeasurementCoupler material: Al 6061Coupler propertiesShear modulus: 26 GPaShear strength: 76 MPaOuter diameter: 1.75 in (4.45 cm)Inner diameter: 0.75 in (1.90 cm)
Figure 18.1: FEA performed on coupler showing strain developed under a simulated load
Logan McCall
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Vendor: Grainger inch steel railsSlot design to ensure alignment Linear Motion: 2 Rail Ball Bearing GuideFigure 19.1: Linear guide system
Logan McCall
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Frame DesignSteel frame Shape: hollow square shaped cross-sectionDimensions:1/8 in inner supports 304 stainless steel1/8 in outer frame low carbon 1015 steel
Figure 20.1: CAD drawing of frame (bottom view)
Logan McCall
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Final Design
Logan McCall
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Prototype Testing
Mark Swain
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Tester was successful in breaking aluminum specimenFracture was at centerDuring initial testing, free end chuck had slight rotationSolution: Force fit new connecting rod into free end Cylindrical grips slipped during initial testingSolution: Use hex-grip specimen or increase friction on cylindrical specimenTesting Results
Figure 23.1: Fractured specimens
Mark Swain
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BudgetBudget: $2,000Spent: $1,844Net: + $156
Mark Swain
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Project ProgressionFall Background researchDesign breakdownComponent researchDesign analysisOptimal part selectionBudget breakdownPurchase orders
SpringDelivery of partsMachining AssemblyMotor/VFD testingPrototype testingTroubleshootingFinal assemblyMark Swain
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ConclusionMaximum torque output: 100NmMachine must fit in an area (footprint) of 1m2Monotonic (one direction)free-end torsion loading Free end must allow for axial motionCompatible with measurement equipment used by AFRLBudget - $2,000
Mark Swain
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The team was successfully designed and manufactured a tabletop torsion tester for AFRLWhat we learned:Focus on the main customer requirements Consult as many resources as possibleTeamwork is essentialUnforeseen circumstances Conclusion
Figure 27.1: Final assembly
Mark Swain
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Questions?
4/15/2015Group 13
Carter, B. (2008). Texas Instruments: Op Amp Noise Theory and Applications. Retrieved September 22, 2014Flater, P. (2014). Tabletop Torsion Test. Eglin, FL: Air Force Research Laboratory.Ilic, M. (2014, October 11). Clamp for centering. Retrieved from GRABCAD: https://grabcad.com/library/stega-za-centriranje-clamp-for-centering-1Lathe Chuck. (2014, October 7). Retrieved from GRABCAD: https://grabcad.com/library/lathe-chuck-3Linear Motion Systems. (2014, September 28). Retrieved from Stock Drive Products: https://sdp-si.com/eStore/coverpg/linearmotion.htm
ReferencesMark Swain
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4/15/2015Group 13Speaking: # of 27Final Presentation
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Fall Gantt Chart
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Spring Gantt Chart
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Specimen Dimensions
Brendan KeaneUnits in inches
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Appendix
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4/15/2015Group 13Speaking: # of 27Final Presentation
4/15/2015Group 13Speaking: # of 27Final Presentation