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Q1- What is a composite?
a. Recycled waste
b. A chemical reaction
c. The latest computer software
d. A structural material consisting of two or more constituents.
A composite is a structural material which consists of combining two or more constituents
a. naturally found
b. traditionally used in aerospace industries
c. low performance composites
Answer:
Advanced composites are traditionally used in aerospace industries
a. True
b. False
Answer:
Composites are generally difficult to repair
a. Length
b. Orientation
c. Shape
d. All of the above
Answer:
Length, orientation, and shape all contribute to the mechanical performance of a composite
a. Polymer Metal Composition
b. Polymer Matrix Composite
c. Polyethylene Metal Composition
Answer:
PMC stands for Polymer Matrix Composite
a. Metal Matrix Composites
b. Polymer Matrix Composites
c. Ceramic Matrix Composites
Answer:
The most common advanced composites are Polymer Matrix Composites
a. glass, steel, and aluminum
b. glass, graphite, and kelvar
c. glass, steel, and kelvar
Answer:
The most common fibers used in advanced polymer composites are glass, graphite, and kelvar
a. Electrical applications
b. Environmental applications
c. Evaporative applications
Answer:
E-glass type fiber is used for electrical applications
a. high cost of fabrication
b. no body needs them
c. they are extremely heavy
Answer:
One of the major drawbacks of composites is their relatively high cost of fabrication
a. Structural Metal Composite
b. Strong Metal Composite
c. Sheet Molding Compound
Answer:
SMC stands for Sheet Molding Compound
a. 5 percent
b. 10 percent
c. 15 percent
d. -15 percent
Answer:
Annual growth of composites is at a steady rate of 10 percent
a. 50
b. 350
c. 3500
d. 30000
Answer:
Reducing one pound of mass in a commercial aircraft can save up to 350 gallons per year?
a. True
b. False
Answer:
The material of the fiber directly influences the mechanical performance of a composite
a. Rectangular
b. Triangular
c. Circular
Answer:
The most common fiber shape is circular
a. MPa-m
b. MPa^0.5-m
c. MPa-m^0.53
Answer:
The units of fracture toughness are MPa-m^0.5
a. 93-95%
b. 92-95%
c. 93-94%
d. 90-95%
Answer:
A typical range of carbon content in carbon fiber is 93-95%
a. 99%
b. less than 99%
c. more than 99%
d. 98%3
Answer:
Graphite fibers have more than 99% carbon content
a. Covalent bond
b. Vanderwaals bond
c. Atomic bond
d. none of the above
Answer:
Thermoset plastic polymers have Vanderwaals type bonding
a. 750 degrees Fahrenheit
b. 1750 degrees Fahrenheit
c. 450 degrees Fahrenheit
d. 350 degrees Fahrenheit
Answer:
Current service temperature limits for polymers reach 750 degrees Fahrenheit
a. Boron-Epoxy
b. Graphite-Epoxy
c. Carbon-Carbon
d. All of the above
Answer:
Mechanical fasteners are made of Carbon-Carbon composites
a. a material with different properties in all directions
b. a material with the same properties in all directions
c. a material with elastic properties
d. none of the above
Answer:
Isotropic means a material with the same properties in all directions
a. isotropic but not homogeneous
b. homogeneous but not isotropic
c. both homogeneous and isotropic
d. neither homogeneous or isotropic
Answer:
Composite materials are neither homogeneous or isotropic
a. materials with different properties in all directions
b. materials with the same properties in all directions
c. materials with the same properties in two perpendicular directions
d. none of the above
Answer:
Anisotropic materials have different properties in all directions
a. two or more different composite systems
b. two or more different fibers used in the same ply
c. both a and b
d. none of the above
Answer:
Inter-ply hybrid composites consist of two or more different composite systems
a. Carbon, Hydrogen, Oxygen and Graphite
b. Carbon, Hydrogen, Oxygen and Nitrogen
c. Carbon, Hydrogen, Oxygen
d. Carbon, Hydrogen, Nitrogen
Answer:
Aramid fibers are made up of Carbon, Hydrogen, Oxygen and Nitrogen
a. polyethylene
b. polyesters
c. phenolics
Answer:
A typical example of thermoplastics include polyethylene
a. filament winding
b. autoclave forming
c. resin transfer molding
d. none of the above
Answer:
Polymer matrix composites are manufactured in the automotive industry where short production runs are necessary by resin transfer molding
a. Carbon-Carbon
b. Graphite-Epoxy
c. Boron-Epoxy
d. none of the above
Answer:
Graphite-Epoxy is replacing metals in golf club shafts
a. high cost
b. low mechanical strength
c. high void content
d. brittleness
Answer:
High cost is a drawback for phenolic resin systems
a. Kelvar
b. Graphite
c. Boron
d. Glass
Answer:
Bullet proof vests use Kelvar
a. Graphite
b. Boron
c. Kelvar 49
d. Kelvar 293
Answer:
High performance applications in the aerospace industry use Kelvar 49
a. Decompose on heating
b. Soften on heating
c. Harden on heating
d. none of the above
Answer:
Thermoset polymers decompose on heating
a. Young's modulus / density
b. (Young's modulus ^ 0.5) / density
c. (Young's modulus ^ 0.3333) / density.
Answer:
The performance indicator for buckling of a rod under a compressive load is (Young's modulus ^ 0.5) / density
a. Square root of Young's modulus / density
b. Strength / density
c. Young's modulus / density
Answer:
Specific modulus is given by Young's modulus / density
a. slice glass
b. vapor deposition method
c. graphite
Answer:
Glass fibers are made from slice glass
a. Phenolic
b. Epoxy
c. Polyester
d. Polymide
Answer:
Polymide is not desirable for smoke emmision
a. Phenolic
b. Epoxy
c. Polyester
d. Polymide
Answer:
Epoxy has the maximum strength
a. Phenolic
b. Epoxy
c. Polyester
d. Polymide4
Answer:
Polymide has the highest service temperature
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