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Design Review

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Aaron Scrignar…..Team Leader

Eric Draves……Historian

Trevor Moody……Web Page Des., Mediator

Stacy Davison……Document Coord., Financial Officer

LaTanya Williams……Communicator

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Outline

• Client Description• Problem Definition• Project Needs• Design Philosophy• Design Method• Design Evolution• Final Design • Analysis• Remaining Project Schedule

– Spring 2003 • Project Funding• Time Log• Conclusion

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More about…

• Specializes in defense systems, government and commercial electronics, business aviation and special mission aircraft

• Chairman & CEO: Daniel P. Burnham• $16.9 billion revenue in 2001• 79,000 employees worldwide• Headquarters located in Lexington, MA

Raytheon

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Client Contact

• Brian Scott– Electronic Systems– B.S.E. from NAU in Mechanical Engineering– Masters Degree at U of A– Worked at Raytheon for seven years

• Tucson, Arizona

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Problem Statement

• Preliminary design and proof-of-principal prototype needed for a window positioning system to be used in a tank-launched infrared guided warhead

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Seeker Device Layout

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Project Needs

• Survive 10KG launch• Packaged in 0.2” thick by

2.9” diameter cylinder, excluding electronics

• Move a Germanium lens .04” thick by .6” diameter to cover a photocell array

• Lens must stay in position for 1 second, and move in and out of the field in less than 1 second

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Launch Conditions

•Set Back: 10,000G

•Balloting: 3,300G

•Set Forward: 2,000G

Flight Conditions

•Lateral: 0-3G

•Vibration: 5G

Shock Response Spectra

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Scope of Design Constraints

• One penny subject to

10,000 G’s weighs

approximately 59 lbs.

• The restricted thickness

of the work area is about

the thickness of 3 ½ quarters

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Design Philosophy

• K.I.S.S.- Minimize number of parts to reduce probability

of failure

• Keep close contact with client – Brings attention to potential design problems

before it’s too late

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Design Method

• Brainstorming- Mechanism ideas• Mechanism Selection- Based on size constraints• Modeling- Cardboard model to assess geometries• Analysis- Hand calculations, Adams, Cosmos • Finalize Design- Select dimensions, Tolerance

fitting• Fabrication- Large scale model and actual

prototype

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Design Evolution

• Design One

– Two solenoids

– Sliding rails

– Return spring

• Design Problems

– Large actuation distance

– Unnecessary parts

– Space limitation

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Design Evolution

• Design Two– Solenoid– Arm– Pin close to edge– Spring return

• Design Problems– Arm deflection– Pivot position accentuates

balloting forces– Requires a latching

mechanism

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Selected Design

• Design Three

– Solenoid

– Arm

– Mid-arm pin position

– Spring return

– Deflection supports

– Counterweight

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Component Selection

• Solenoid – PO-6 3Volt

• Arm – 7075 T6 Aluminum

• Pin – Stainless Steel with bronze bushing

• Frame –Ti-6A1-4V HT-46

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Selected Solenoid

• Meets necessary criteria:

- Dimensions

- Actuation Length

- Forces

- Power Requirements

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Selected Solenoid (cont.)

Full Arm Swept Angle:53 Degrees

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Arm Design

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Pin Connection Design

PIN

BUSHING FRAME PLATE

ARM

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Frame Design

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Modeling

• Made actual size

cardboard and CAD

models to assess

the fit of components

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Analysis Justification

• Deformation of surfaces are within tolerances defined by the optical engineer

• Deformation of support structure for optical and antenna elements is within tolerance and creates no interference

• No ultimate failures occur and probability of failure is less than 0.01%

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Analysis

• Hand Calculations – Arm deflection– Arm material failure for normal forces– Arm material failure for balloting forces– Pin material failure for balloting forces– Required swept angle of arm

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Analysis (cont.)

Adams – Arm actuation time

Full Arm Swept Angle:53 Degrees

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Future Tasks

• Component FEA analysis

• Pin press fit calculations

• Order materials

• Fabrication

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Remaining Project Plan Spring 2003

• Status Report #3 March 27• Prototype Complete April 12• Test in Rail Gun April 15• Design Presentation April 22• Capstone Conference April 25• Finalize Web Page and Report May 2

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Project Funding

• Raytheon provided $3,000 for project costs– Prototype $1900– Travel Expenses $500– Documentation Material $500– Modeling $100

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Purchases to Date

• 8 SP-25 solenoids (two 3-volt, four 6-volt, two 12-volt) – testing, prototype

• 8 PO-25-6 (two 3-volt, four 6-volt, two 12-volt) – testing, prototype

• Cork – modeling• Cutting supplies – modeling• Birch plywood – modeling • Balsa wood - modeling

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Time Log

• Aaron Scrignar 71.95• Eric Draves 71.00• Trevor Moody 43.25• Stacy Snyder 32.55• LaTanya Williams 39.75

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Total Hours: 258.5 hrs

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Conclusion

• The balanced swing arm design is simple and efficient in providing the required lens motion while withstanding the environmental constraints

• Prototype fabrication will be complete by April 12, 2003 for Rail Gun test

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Questions?