MSE 250 - Ch24 Composites - Final Exam Flashcards

1. Composites are used in __, __, __ __, and __.

a. airplanes; window glass panes; motorcycles; ice-skates; computer hard-drives

b. airplanes; bicycles; motorcycles; ice-skates; computer hard-drives

c. airplanes; bicycles; metal spoons; ice-skates; computer hard-drives

d. airplanes; bicycles; motorcycles; plastic grocery bags; computer hard-drives

e. none of the above

b. airplanes; bicycles; motorcycles; ice-skates; computer hard-drives

2. In the year 2000, the top two areas for composite products (in Billions of pounds of shipments) were __ and __.

a. transportation; construction

b. computers; software

c. clothing; home fabrics

d. glass window panes; computers

e. none of the above

a. transportation; construction

3. Composite materials can be classified as __ reinforced and __ reinforced materials.

a. sheet; roll

b. fiber; particle

c. positive; negative

d. ferrite; austenite

e. none of the above

b. fiber; particle

4. Fiber-reinforced composite materials can be classified as __ fiber reinforced and __ fiber reinforced materials.

a. temporary; permanent

b. positive; negative

c. continuous; discontinuous

d. iron; steel

e. none of the above

c. continuous; discontinuous

5. Discontinuous-fiber-reinforced composite materials can have fibers that have __ or __ orientations.

a. up; down

b. left; right

c. parallel; perpendicular

d. random; preferred

e. none of the above

d. random; preferred

6. Continuous-fiber-reinforced composite materials can have __ or __ structures.

a. up; down

b. left; right

c. parallel; perpendicular

d. single layer; multi-layer

e. none of the above

d. single layer; multi-layer

7. Single-layer continuous-fiber composites can have __ or __ reinforcement.

a. up; down

b. left; right

c. unidirectional; bidirectional

d. positive; negative

e. none of the above

c. unidirectional; bidirectional

8. Multi-layer continuous-fiber composites can be __ or __.

a. up; down

b. laminates; hybrids

c. positive; negative

d. left; right

e. none of the above

b. laminates; hybrids

9. Particle-reinforced composites can have __ or __ orientations.

a. random; preferred

b. up; down

c. positive; negative

d. left; right

e. none of the above

a. random; preferred

10. Fiber alignment in a composite can be __, __ or __.

a. aligned continuous; aligned discontinuous; random discontinuous

b. random continuous; aligned discontinuous; random discontinuous

c. positive; negative; zero

d. random continuous; aligned continuous; random discontinuous

e. none of the above

a. aligned continuous; aligned discontinuous; random discontinuous

11. Composites are __ materials that contain a __ and a __.

a. single-phase; solute; solvent

b. multi-phase; matrix; reinforcing phase

c. multi-phase; solute; solvent

d. single-phase; matrix; reinforcing phase

e. none of the above

b. multi-phase; matrix; reinforcing phase

12. In a composite, the matrix is the __ phase, and the reinforcing phase __ the matrix __.

a. discontinuous; reinforces; weakness

b. discontinuous; softens; strength

c. continuous; enhances; properties

d. continuous; improves; nuclear properties

e. none of the above

c. continuous; enhances; properties

13. Composites can be classified as __ matrix composites, __ matrix composites and __ matrix composites.

a. nuclear; electronic; magnetic

b. metal; metallic; metalloid

c. positive; negative; neutral

d. metal; ceramic; polymer

e. none of the above

d. metal; ceramic; polymer

14. MMC composites are __ composites.

a. metal-matrix

b. multi-molecular

c. multi-metal

d. multi-matrix

e. none of the above

a. metal-matrix

15. CMC composites are __ composites.

a. composite-matrix

b. ceramic-matrix

c. cement-matrix

d. ceramic-metal

e. none of the above

b. ceramic-matrix

16. PMC composites are __ composites.

a. polymer-metal

b. poly-molecule

c. polymer-matrix

d. positive-matrix

e. none of the above

c. polymer-matrix

17. Addition of a reinforcing phase to a metal (to create a metal-matrix composite) __ the yield-strength, __ the tensile-strength, and __ the creep-resistance of the material.

a. decreases; increases; increases

b. increases; decreases; increases

c. increases; increases; decreases

d. increases; increases; increases

e. none of the above

d. increases; increases; increases

18. Addition of a reinforcing phase to a ceramic (to create a ceramic-matrix composite) __ toughness of the material.

a. increases the

b. decreases the

c. maintains the same

d. makes infinite the

e. none of the above

a. increases the

19. Addition of a reinforcing phase to a polymer (to create a polymer-matrix composite) increases the __, __, __, and __ of the material.

a. Miller indices, ductility; tensile strength; creep resistance

b. Bragg modulus, yield-strength; malleability; ductility

c. Young's modulus, ductility; tensile strength; creep resistance

d. Young's modulus, yield-strength; tensile strength; creep resistance

e. none of the above

d. Young's modulus, yield-strength; tensile strength; creep resistance

20. Reinforcing phases (for use in a composite material) can be classified as __, __ or __ phases.

a. positive; negative; neutral

b. electronic; nuclear; crystallographic

c. particle; fiber; structural

d. electron; proton; neutron

e. none of the above

c. particle; fiber; structural

21. An example of a metal-matrix aligned-continuous-fiber composite is __ by __.

a. gamma-prime(Ni3Al)-alpha(Mo); eutectoid reaction

b. gamma-prime(Ni3Al)-alpha(Mo); eutectic solidification

c. gamma-prime(Ni3Al)-alpha(Mo); peritectic reaction

d. iron-ceramic; sintering

e. none of the above

b. gamma-prime(Ni3Al)-alpha(Mo); eutectic solidification

22. In the gamma-prime(Ni3Al)-alpha(Mo) metal-matrix composite, __ is the matrix material, and it is __.

a. alpha molybdenum; ductile

b. Ni3Al; ductile

c. alpha molybdenum; brittle

d. Ni3Al; brittle

e. none of the above

a. alpha molybdenum; ductile

23. In the gamma-prime(Ni3Al)-alpha(Mo) metal-matrix composite, __ is the fiber material, and it is __.

a. gamma-prime(Ni3Al); ductile

b. gamma-prime(Ni3Al); brittle

c. alpha molybdenum; brittle

d. alpha molybdenum; ductile

e. none of the above

b. gamma-prime(Ni3Al); brittle

24. An example of a ceramic-matrix aligned-continuous-fiber composite is __ with __ fibers formed by a __ slurry.

a. glass; SiC; glass

b. SiC; glass; SiC

c. iron; glass; iron

d. glass; iron; glass

e. none of the above

a. glass; SiC; glass

25. Glass is __ compared to SiC.

a. more stiff

b. less stiff

c. the same stiffness

d. zero stiffness

e. none of the above

b. less stiff

26. An example of a randomly-oriented particle-reinforced metal-matrix composite is __ steel.

a. spheroidite

b. ferrite

c. martensite

d. austenite

e. none of the above

a. spheroidite

27. In spheroidite steel, the matrix is __ which is __, and the particles are __, which are __.

a. alpha ferrite; ductile; Fe3C cementite; ductile

b. alpha ferrite; ductile; Fe3C cementite; brittle

c. Fe3C cementite; brittle; alpha ferrite; brittle

d. Fe3C cementite; brittle; alpha ferrite; ductile

e. none of the above

b. alpha ferrite; ductile; Fe3C cementite; brittle

28. An example of a randomly-oriented particle-reinforced polymer-matrix composite is __.

a. a boat sail

b. an optical fiber

c. an automobile tire

d. a fiberglass boat

e. none of the above

c. an automobile tire

29. In an automobile tire, the matrix is __ which is __, and the particles are __, which are __.

a. carbon black; compliant; rubber; stiffer

b. rubber; stiff; carbon black; more compliant

c. carbon black; stiff; rubber; more compliant

d. rubber; compliant; carbon black; stiffer

e. none of the above

d. rubber; compliant; carbon black; stiffer

30. A laminated composite panel is typically made of __ and __ __-reinforced sheets.

a. 1-D; 2-D; fiber

b. stacked; bonded; fiber

c. 1-D; 2-D; particle

d. stacked; bonded; particle

e. none of the above

b. stacked; bonded; fiber

31. The stacking sequence of the reinforced sheets in a laminated composite panel is typically __ followed by __ degrees, and this sequence is repeated multiple times.

a. 0; 0

b. 0; 90

c. 0; 60

d. 0; 45

e. none of the above

b. 0; 90

32. The benefits of a laminated composite panel include __.

a. in-plane stiffness

b. out-of-plane stiffness

c. in-plane flexibility

d. in-plane ductility

e. none of the above

a. in-plane stiffness

33. Examples of polymer matrices used in polymer-matrix-composites include __, and __.

a. iron; polyester; urethane

b. epoxy; ceramic; urethane

c. epoxy; polyester; SiO2

d. lead glass; polyester; urethane

e. epoxy; polyester; urethane

e. epoxy; polyester; urethane

34. Polymer matrices have __ density.

a. high

b. zero

c. infinite

d. low

e. none of the above

d. low

35. Examples of fibers that are used in polymer-matrix composites include __, __ and __.

a. lead glass; borosilicate glass; high silica glass

b. graphite; Kevlar; boron

c. iron; nickel; chromium

d. Pb; Sn; Cd

e. none of the above

b. graphite; Kevlar; boron

36. The drawbacks of polymer-matrix composites include __ operating temperature, __ coefficients of thermal expansion, issues with __ absorption, and __ elastic modulus.

a. low; high; moisture; low

b. high; high; oxygen; low

c. high; low; moisture; high

d. low; low; oxygen; high

e. none of the above

a. low; high; moisture; low

37. A PMC composite is a __ composite.

a. poly-molecule

b. polymer-matrix

c. polymer-metal

d. poly-metal

e. none of the above

b. polymer-matrix

38. In a PMC composite, the __ holds fibers in place.

a. reinforcement

b. particles

c. matrix

d. precipitates

e. none of the above

c. matrix

39. In a PMC composite, the matrix transfers __ in __ fibers or __ fiber composites.

a. electric fields; continuous; discontinuous

b. magnetic fields; broken; short

c. metallic conduction; continuous; discontinuous

d. stress; broken; short

e. none of the above

d. stress; broken; short

40. In a PMC composite, the matrix acts as a __ to the environment, and __ fiber surfaces.

a. conduit; protects

b. conduit; exposes

c. barrier; exposes

d. barrier; protects

e. none of the above

d. barrier; protects

41. In a PMC composite, the matrix controls inter-laminar and in-plane __.

a. mass

b. volume

c. shear strength

d. pressure

e. none of the above

c. shear strength

42. In a PMC composite, the matrix controls __ and __ resistance.

a. processibility; magnetic

b. processibility; heat

c. sentience; heat

d. sentience; magnetic

e. none of the above

b. processibility; heat

43. In a PMC composite, the matrix can contribute to __ tolerance.

a. damage

b. stress

c. strain

d. fatigue

e. none of the above

a. damage

44. A non-reinforced polymer resin has a strength of about 1E-2 psi. When it is reinforced with short fibers, its strength __ to __ psi in a longitudinal direction.

a. increases; 4E2

b. increases; 4E-2

c. decreases; 2E-4

d. decreases; 2E4

e. none of the above

b. increases; 4E-2

45. A non-reinforced polymer resin has a strength of about 1E-2 psi. When it is reinforced with continuous long fibers, its strength __ to __ psi in a longitudinal direction.

a. decreases; 1E-13

b. increases; 1E-13

c. increases; 13E-2

d. decreases; 13E-2

e. none of the above

c. increases; 13E-2

46. The strength (in a longitudinal direction) of a short-fiber reinforced PMC is __ that (in a longitudinal direction) of a long-continuous fiber reinforced PMC.

a. less than

b. greater than

c. equal to

d. infinite compared to

e. none of the above

a. less than

47. The strength of a short-fiber reinforced PMC, in a longitudinal direction, is __ that of the same PMC in a transverse direction.

a. less than

b. greater than

c. equal to

d. infinite compared to

e. none of the above

b. greater than

48. The strength of a continuous-long-fiber reinforced PMC, in a longitudinal direction, is __ that of the same PMC in a transverse direction.

a. less than

b. greater than

c. equal to

d. infinite compared to

e. none of the above

b. greater than

49. A Boeing 757 uses __ for the rudder.

a. graphite

b. steel

c. plastic

d. ceramic

e. none of the above

a. graphite

50. A Boeing 757 uses a __ composite for the engine-strut fairings.

a. steel

b. plastic

c. Kevlar/fiberglass

d. ceramic

e. none of the above

c. Kevlar/fiberglass

51. A Boeing 757 uses a __ composite for the wing leading-edge lower panels.

a. steel

b. plastic

c. Kevlar/fiberglass

d. ceramic

e. none of the above

c. Kevlar/fiberglass

52. A Boeing 757 uses a __ composite for the wing trailing-edge lower panels.

a. steel

b. plastic

c. ceramic

d. graphite/Kevlar + Kevlar mat

e. none of the above

d. graphite/Kevlar + Kevlar mat

53. When we look at Polymer matrix performance as a function of Mach number (speed of plane with respect to sound), __ composites are the best choice for very high airplane speeds of about 10 Mach.

a. carbon-carbon

b. steel

c. plastic

d. ceramic

e. none of the above

a. carbon-carbon

54. Carbon-carbon composites can operate at temperatures as high as __ to __ degrees C.

a. 7.5; 9.5

b. 750; 950

c. 75; 95

d. 7500; 9500

e. none of the above

b. 750; 950

55. The specific strength of aluminum alloys is __ that of titanium alloys.

a. less than

b. greater than

c. equal to

d. infinite compared to

e. none of the above

a. less than

56. The specific strength of titanium metal-matrix composites is __ that of titanium alloys.

a. less than

b. greater than

c. equal to

d. infinite compared to

e. none of the above

b. greater than

57. The specific strength of aluminum metal-matrix composites is __ that of aluminum alloys.

a. less than

b. greater than

c. equal to

d. infinite compared to

e. none of the above

b. greater than

58. The specific strength of carbon-fiber epoxy composites is __ that of aluminum alloys.

a. less than

b. greater than

c. equal to

d. infinite compared to

e. none of the above

b. greater than

59. Polyimides have __ heat-deflection temperatures compared to epoxies.

a. lower

b. higher

c. the same

d. infinite

e. none of the above

b. higher

60. Polyimides are __ in cost per pound, compared to epoxies.

a. lower

b. higher

c. the same

d. infinite

e. none of the above

b. higher