8/3/2019 Tech Paper- Breaking the Sound Barrier

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Breaking the Sound Barrier:Carbon Fiber and E105 Epoxy 20,000 Feet Up

Austin SchaderMatE 330 April 26, 2011

Background flutter that occurs when the high flight wind speedWhen Calpoly Space Systems set their sights on

breaking the 20,000 foot barrier in their next rocket

launch, they knew they would need an advanced

material. They selected E105 Resin and 205

Hardener from West Systems

reinforced with

carbon fiber prepreg sheets (Figure 1).

Figure 1 - Carbon Fiber nose cone and fin can.1 Carbon fiber

provides both a strong and stable nose cone and an excellent

surface finish.

Carbon fiber was invented in 1879 by Thomas

Edison for use in light bulb filaments. These fibers

had high temperature resistance but a lower tensile

strength and elastic modulus than modern carbonfibers

2. Modern production began in the 1960s

spurred by military requirements for aerospace

applications such as high strength, high stiffness, and

low density.

Epoxys birth began when Russian Chemist

Prileschajev synthesized epoxied groups from olefin

precursors in the early 1900s3. A thermoset, epoxies

provide a matrix for carbon fiber that creates

excellent adhesion to fibers, low shrinkage in curing,

and a wide variety of properties, as many resins and

hardeners are available3. West Systems

was founded

in 1969 and produces epoxies for a variety of uses.

ApplicationThe Calpoly Space Systems rocket is 15 tall, 6.25

inches in diameter, and weighs just under 50kgs4. The

nose cone is 24 long. The overall surface finish must

be as smooth as possible. During flight the nose cone

experiences 8-9 Gs and must withstand wind speeds

well over 600 mph4. In addition dampening ability

must be maximized so the rocket does not experience

matches the natural frequency of the material.

ScienceCarbon contains very strong covalent bonds in its

hexagonal structure in each plane of hexagons, but

weak bonds between each planes. During processing

the strong planes are aligned in different directions

depending on the application to create strength in the

desired orientation. Additionally the fibers are

processed to diameters of 10 m or smaller whichminimizes surface defects promoting strength. These

factors make carbon fiber one of the strongest

materials (Figure 2).

Figure 2 - Tensile Strength of common aerospace composites5.

E105 Epoxy from West Systems

is an aromatic

epoxide resin utilizing 205 Hardener. This

combination allows for a shorter B-Stage (working

time) and a very highly cross-linked polymer matrix

for the carbon fiber. This high degree of crosslinking

causes the matrix to become both stiffer and stronger.

Together with carbon fiber a light, chemically

resistant, strong, high dampening ability, and stiff

material is created.

References1.Carbon fiber fin: U.S. Rockets 2011, Cited 4/22/2011 http://v-serv.com/usr/crr54mm.htm 2. History Carbon Fiber: Illstreet.Com 2011, Cited

4/22/2011http://www.carbon-fiber-hood.net/cf-history

3.Hempel: Hempel 2011http://www.hempel.com/Internet/inecorporatec.nsf/ 4. CPSS information & Specs. R. Bauer, Aero 3rd Year, 4/22/2011

5.Tensile Strength: Bike 2011 Cited 4/22/2011http://www.bikehps.com/bst/acg/tensile_strength.gif

http://www.carbon-fiber-hood.net/cf-historyhttp://www.carbon-fiber-hood.net/cf-historyhttp://www.carbon-fiber-hood.net/cf-historyhttp://www.hempel.com/Internet/inecorporatec.nsf/http://www.hempel.com/Internet/inecorporatec.nsf/http://www.hempel.com/Internet/inecorporatec.nsf/http://www.bikehps.com/bst/acg/tensile_strength.gifhttp://www.bikehps.com/bst/acg/tensile_strength.gifhttp://www.bikehps.com/bst/acg/tensile_strength.gifhttp://www.hempel.com/Internet/inecorporatec.nsf/http://www.carbon-fiber-hood.net/cf-history

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