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New Castle Design AssociatesPROJECT 99.12

TEAM 12Composite Generator Enclosure

TEAM 12Composite Generator Enclosure

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Composite Generator Enclosure• Team 12 • Justin Schaffer

• Tom Winward• Noel Goldstein• Jeremy Freeman

Members:

• Partner: Center for Composite Materials• Advisor: Dr. Michael Keefe

• Mission: It is our goal to design and construct a prototype portable generator enclosure made from composite materials that successfully satisfies all the wants and constraints defined by our customers, and to have a prototype built by April 1999.

• Approach: We will first identify customers and their wants. We will also attempt to find all current technology in use for sound reduction and in the area of composites. Then concepts will be developed based on the information gained during our benchmarking. The best design will be determined by comparing our concepts with customer wants and constraints. Next we will begin a process of prototype design and evaluation, culminating with the production of a prototype part. This prototype is then to be further developed by CCM to fit the D Star generator.

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Background

• Army needs portable generator for use in remote locations

• D-Star Engineering designing lightweight, high power diesel generator

• Team 12 to design a prototype enclosure

• CCM to finish development for pre-production model

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Customers

• D-Star Engineering• U.S. Army• New Castle Design Associates• Safety Organization (NFPA)• Army Soldier• Home Owners• Construction Industry• Outdoor Entertainment• RV Owners• Emergency Services

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Wants and Constraints

• Will not break• Thermally Stable • Quiet• Portable• Stackable

•Ease of Operation•Longevity•Ease of Maintenance•Cost

15” x 16” x 30” 25 LBS Composites

•Maximum Size•Maximum Weight•Primary Materials

Constraints

Wants

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Benchmarking

System Level• Open Tubular Frame

• Westerbeke Clamshell Enclosure

• Honda Super Quiet Generators

• Fisher Panda Generators

• Previous UD NCDA Enclosure

Functional• Sound Suppression• Accessibility• Ventilation/Heat Rejection• Stackable• Rolling• Carrying• Weather Exposure• Ease of Starting

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System Level Best Practices

• Years of Exposure Painted Metal• Tg N/A • Weight Open Frame• Cost Open Frame• Sound Level Enclosed Box• Drop Test ?• Stackable N/A• Time to Access Open Frame• Time to Start Electric Start

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Metrics and Target Values

• Years of Exposure 10 yrs / 3000 hrs• Tg 350F / 800F• Weight 25 lbs• Cost $200• Sound Level 60 dB / 65 dB max • Drop Test 4 ft• Stackable 5 units high• Time to Access 10 min• Time to Start 1 min

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Physical Model Testing1

• Sound Testing

• Temperature Testing

• Unenclosed/ Enclosed Generator• Load/ No Load

• Enclosed• Forced Convection

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Physical Model Testing2

...The Equipment

Sound Test...

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Critical Concepts

• Stackable

• Access to interior

• Portable

• Quiet, Longevity, Cost, Will not break, Thermally stable

Rectangular

Panels (removable, hinged, sliding)

Handles, Wheels

Composite sandwich

Wants Concepts

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Concepts1

“Hand Buggy” Style with 6 removable access panelsAdvantages: Easy Access and Mobility

Disadvantages:Not Structurally Sound

“Clam Shell” Design with4 Dolly wheelsAdvantages: Easy to Roll on smooth surfaces, Easy Access

Disadvantages: Large Stress Concentrations

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Concepts2

Multiple roller wheels and

Sliding Side Door Access

Advantages: Easy to Use

Disadvantages: Limited Access and difficult outdoor mobility

2 Piece Shell Access

Advantages: Easy to Use

Disadvantages: High Stress on Latches

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Concept Selection

Mobility

Access

Composite Structure

Hand Buggy Style with Additional Handle

Multiple Panels at Critical Locations

Ciba Resinfusion 8605 Epoxy, E-Glass and Kevlar Fibers, Phenolic Foam Core

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• Phenolic Foam Core did not hold up structurally in initial sample tests

• Further research led to the testing of a Balsa Wood Core

S.C.R.I.M.P.

CIBA RESINFUSION 8607

Composite Structure Selection

Kevlar 49

E-Glass

Phenolic Closed Cell Foam Core

Kevlar 49

E-Glass

Balsa Wood Core

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Composite Lay Up2

• Samples made and tested with varying numbers of layers of fabric around balsa wood core

3 Point Bend Test Drop (Impact) Test

Test Samples

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• Best Lay Up: 2 layers of Kevlar 49, and 2 layers of E Glass.

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Final Concept

Hinged Starting Panel

Removable Top Panel

Recessed

Wheels

3 Recessed Handles

Kevlar 49 (2), Balsa Wood, E-Glass (2)

Sandwich Structure

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Concept Testing1

• Sound Reduction:– Maximum 64.5 dB sound level in open

parking lot, measured at 7m.

• Temperature:– 160-170 oF inside

• Size:– 15”x16”x30”

• Weight:– 22 Pounds without louvers, handles and

wheels (These will add approximately 8 pounds)

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Concept Testing2

• Drop Test:– 4 ft. Off loading dock onto asphalt; sustained only

minimal damage• Access Time:

– 30 sec. to remove starting door, and replace– 5 min. to remove top cover to access engine and

replace• Stackable:

– Supported 400 pounds on top

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Prototype BudgetMaterials

• MOLD–Wood & Miscellaneous (including Bondo Body Filler, Paint, Sand Paper, Screws, etc…)

• SCRIMP–Ciba Resin–Kevlar–E Glass–Phenolic Foam–Balsa Wood–SCRIMP Materials (including Vacuum Bag, Tubing, Tacky Tape, Peel Ply, & Distribution Medium)

• OTHER–Film and Developing–Decibel Meter

TOTAL

Team Cost

• $ 399.68

• $ 0.00• $ 105.00• $ 671.25• $ 181.30• $ 414.00• $ 167.51

• $ 30.00• $ 30.00

• $ 1,998.74

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Est. Engineering & Shop Hours

• Fabrication:

– Wooden Model...16

– Mold…………..400

– Test Panels……..60

– SCRIMP………200

– Finishing………..15

– Testing…………...6

TOTAL………..697

• Research&Development:

– Benchmarking..…….40

– Customers/Wants…..20

– Foam Core Design....40

– Balsa Core Design....70

– Shape………..……..65

– Mat’l Procurement…20

TOTAL………..….255

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Projected Production Costs

• Kevlar:

• E-Glass:

• Balsa Wood:

• Resin:

• 4 yards

• 3 yards

• 3 1/2 sheets

• 1 gallon

• $ 70.00

• $ 16.11

• $ 41.40

• $ 73.93

Total: $ 201.44

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Conclusion

Our final design has met and exceeded most wants and constraints placed by our customers. Areas for

improvement include decreasing the weight and using a better method to lay-up the composite

fabrics.