Post on 16-Dec-2015
Composite Manufacturing
Group 15 Eglin AFBBrandon Bair - John Brewer - Darnell Brown - Rob Contes
Sponsor: Jeff Wagener - Lt Joe Czabarnek, AFRL
Faculty Advisors: Dr. Chiang Shih (ME) - Dr. Richard Liang (IE)
Introduction
• Scope
• AFRL Fuselage Specifications
• Project Specifications
• Research
• Selection
• Original Design
• Design Development
• Construction
• Testing
• Hiring
• Conclusions
• Recommendations
• Summary
• Questions
Scope
The scope of this project was to redesign and test the fuselage of the Bullwinkle Micro Aerial Vehicle and “hire” a manufacturer to produce it.
AFRL Fuselage
• Length - 15.75”
• Width - 2.25”
• Height - 2.25’’
• Construction
• 2 part Design
• Male mold
• Pre-impregnated carbon fiber
• Assembled with nylon screws
• Motor Mount – Sheet aluminum
Project Specifications
• Same size and shape
• Survive a 30o impact at 20 m/s (45mph)
• Ensure that motor heat will not affect structure
• Manufacturing
• 30 units
• $300 per unit
• $20,000 for start-up
• 1 month start-up, 1 month production
Research
• Materials
• Resin
• Processing
• Curing
Research: Materials
• Glass Fiber
• Carbon Fiber
• Kevlar
Glass Fiber
• Pros
• Lightweight
• Inexpensive
• Cons
• Heavier than
other composites
Carbon Fiber
• Pros
• Light weight
• Very strong
• Durable
• Cons
• Very expensivematerialogical.com/wordpress/?cat=7
• Developed by DuPont in 1965
• Pros
• Thermal and electric insulator
• Absorbs energy
• Cons
• Breaks down in UV light
• Sublimes at 450oC
Kevlar
www.kevlar.com
Research: Resin
• Polyester• Inexpensive• Low order crosslinking
• Epoxy• Difficult to use• High order crosslinking
• Vinyl Ester• Compromise• Easy to use
Research: Bonding Processes
• Resin Transfer
• Contact Molding
• Vacuum Bag
Resin Transfer
• Process• Material held in a closed mold• Resin injected
• Pros• Smooth, even sides• Few voids
• Cons• Complex molds• Resin rich
http://www.rtmcomposites.com/whatrtm.htm2005
Contact Molding
• Also known as Hand Lay-Up Molding
• Material and resin are applied with a roller or brush by hand
• Pros
• Inexpensive
• Fast
• Cons
• Resin rich
• Labor
• Messy
Vacuum Bag Molding
Applies vacuum to hold a part securely to a mold
• Pros
• Product is smoother
• Controlled fiber and resin ratio
• Cons
• Time consuming
• Materials
Possible Curing Processes
• Autoclave – High temperature and pressure
• Oven – High temp
• Room temperature
Selection
• Material – Carbon Fiber
• Light weight
• Strong
• Standard in military MAV construction
• Resin – Vinyl Ester
• Forgiving catalyst ratio
• Strong and tough
• Process – Vacuum Infusion• Control resin ratio• Low voids
• Molds – Female, Plaster
Original Design
• Solid nose
• Main structure with cap
• Four parts
•10 Bonding strips
Design Development
• 4 main parts to 2 main parts
• Flat sheet
• 2 Bonding strips
• Cap
• Simpler
• Faster production
• More continuous structure and surface
Design Development
Construction: Molds• Wooden mold box
• Acrylic
• Wax
• Rapid prototyped
male mold form
• Industrial gypsum plaster
• Wax
Construction: Fuselage
• Wax • Poly Vinyl Alcohol (PVA)• Carbon Fiber• Peel Ply• Flow Media• Vacuum Bag
Bench Test• Run 1
• Full Power for 5 min
• No temperature change
• Run 2
• 50% for 7 min
• No temperature change
• Run 3
• 25% for 15 min
• No temperature change
Impact Testing
• Propelled with a pneumatic cannon• Impacted a target ramp at 30o • Speed measurement – Calibration board and semi-
high speed camera (120 fps)
Impact Results
• With motor
• Minimal damage
• Motor plate separation
• Retained structure
• With weight (3 lb total)
• Visible damage
• Motor plate separation
• Retained structure
Impact
Impact
Hiring
• ACMA
• Preliminary Contact
• Quote Request Package
• Detailed description
• Detailed drawings
• Prototype pictures
• Separate package
for motor plate
Conclusion
• Fuselage Manufacturer –TBD by AFRL
• At least 6 interested companies
• Timeline
• Production
• Motor Plate Manufacturer – Milco Water Jet
• Lot Price - $190 ($6.33 per unit)
• Timeline - 5 days
Recommendations
• Construct parts in house
• Low production numbers
• Quality control
• Variability
• Cost
• Research vacuum molding of polymers
• Quicker
• Less expensive
• Compliant parts
Summary
• Scope
• AFRL Fuselage Specifications
• Project Specifications
• Research
• Selection
• Original Design
• Design Development
• Construction
• Testing
• Hiring
• Conclusions
• Recommendations
• Summary
• Questions
Questions