ME Polymers and Composites 3

Question 1

Which processing technique is most commonly used to manufacture continuous fiber thermoset composite aerospace structures?

Accepted Answer

Autoclave curing of prepreg layups

Answer

Prepreg (pre-impregnated fiber) layups cured in an autoclave under heat and pressure produce the highest quality, void-free thermoset composite structures for aerospace.

Question 2

Sandwich composite structures use a low-density core between face sheets to maximize:

Accepted Answer

Flexural stiffness-to-weight ratio

Answer

Sandwich structures place stiff, strong face sheets far from the neutral axis with a lightweight core, enormously increasing bending stiffness with minimal weight addition.

Question 3

Viscoelastic behavior in polymers means they exhibit properties of both:

Accepted Answer

Elastic solids and viscous liquids

Answer

Viscoelastic materials combine elastic (energy storage) and viscous (energy dissipation) responses, leading to time-dependent deformation phenomena like creep and stress relaxation.

Question 4

The purpose of a sizing (surface treatment) on carbon fibers before embedding in a matrix is to:

Accepted Answer

Improve fiber-matrix interfacial bonding

Answer

Fiber sizing applies a thin chemical coating that improves wettability and chemical bonding between the fiber surface and the matrix, enhancing interfacial shear strength.

Question 5

Vulcanization of natural rubber involves cross-linking chains with:

Accepted Answer

Sulfur bridges

Answer

Vulcanization creates sulfur cross-links between rubber polymer chains, transforming it from a weak, tacky material into strong, elastic rubber with reduced creep.

ME - Materials Engineer Practice Test

ME - Materials Engineer Practice Test

ME Polymers and Composites 3