Composite Materials Mid - I, September - 2014

1.The acronym SMC stands for
  • Structural Metal Composite
  • Strong Metal Composite
  • Sheet Molding Compound
  • Structural metallic compound
Answer: A
2.Specific modulus is given by
  • Square root of Young's modulus / density
  • Strength / density
  • Young's modulus / density
  • Square root of strength / density
Answer: C
3.Bullet proof vests use ___________ fibers.
  • Kelvar
  • Graphite
  • Boron
  • Glass
Answer: A
4.Out of these polymers, which one has the maximum strength?
  • Phenolic
  • Epoxy
  • Polyester
  • Polymide
Answer: B
5.Which of these polymer is least desirable for smoke emission?
  • Phenolic
  • Epoxy
  • Silicone
  • Polymide
Answer: B
6.Thermoset polymers show which of the following traits.
  • Decompose on heating
  • Soften on heating
  • Harden on heating
  • melt on cooling
Answer: A
7.Nanocomposites consist of particles or fibers having mostly this dimension or less?
  • 0.0000001 m
  • 0.000001 m
  • 0.00001 m
  • 0.0001 m
Answer: A
8.Macro-mechanical analysis of a lamina is based on average properties and by considering the lamina to be:
  • Isotropic
  • Homogeneous.
  • Non-homogeneous.
  • Non-linear
Answer: B
9.The stiffness of a unidirectional lamina is usually much larger in the direction:
  • of the fibers
  • perpendicular to the fibers
  • at a 45 degree angle to the fibers
  • of the matrix
Answer: A
10.For a linearly elastic isotropic material undergoing small deformations the elastic modulus can be used to relate:
  • Stress and Strain
  • transform stresses to another co-ordinate system
  • transform strains to another co-ordinate system
  • stress
Answer: A
11.Tape-laying method is adopted for the production of __________.
Answer: Fiber reinforced composites
12.A prepeg with fibers parallel to the long dimension is called ______________.
Answer: Ply or O0 lamina
13.RRIM means _____________.
Answer: Reinforced reaction injection molding
14.The tensorial notation of Hooke’s law is ___________.
Answer: ijσ = C ijkl ε kl
15.Flexibility is measured as the inverse of ________________.
Answer: The product of bending moment (M) and the radius of curvature (R)
16.Human bone is an example of ____________ composite.
Answer: Naturally occuring
17.The average tensile strength of SiC fibers is about ______________.
Answer: 2.8Gpa
18.Silicon carbide is ______________ material.
Answer: Ceramic
19.Young’s modulus E and shear modulus G are related by __________.
Answer: E = 2G(1+ ν)
20.‘B’ is identically____________ for symmetric laminate.
Answer: Zero