复合材料复习题库

复合材料复习题库

9. The transverse tensile strength of an aligned continuous fibre composite

(A) is obtained when testing normal to(垂直于) the fibre axis,

(B) is obtained when testing parallel to（平行于）the fibre axis,

(C) is the lowest tensile stength,

(D) is the highest tensile strength,

(E) depends mainly on the properties of the matrix and of the fibre- matrix interface,

(G) depends mainly on the properties of the fibres.

Each of the sentences in questions 11 to 14 consists of an assertion followed by

a reason. Answer:

(A) if both assertion and reason are true statements and the reason is a correct explanation of the assertion,

(B) if both assertion and reason are true statements but the reason is not a true explanation of the assertion,

(C) if the assertion is true but the reason is a false statement,

(D) if the assertion is false but the reason is a true statement,

(E) if both the assertion and reason are false statements.

11. The coefficient of thermal expansion of an MMC with a ceramic reinforcement is less than that of the matrix because the coefficient of thermal expansion of a ceramic is usually less than that of a metal.

12. Generally reinforcing a metal degrades both ductility and toughness because there is an increase in Young's modulus.

13. Unfortunately reinforcement of a metal markedly reduces the fatigue resistance because cracks are readily formed within the reinforcement.

14. The specific strength and modulus of a silicon carbide particle(碳化硅粒子) reinforced aluminium alloy are superior to those of the matrix because silicon carbide is more dense than the common aluminium alloys.

9. A,C,E; 11. A; 12. B; 13. E; 14. B;

9.Reinforcing alumina with SiC whiskers ABE

(A) enhances the thermal shock resistance,

(B) lowers the coefficient of thermal expansion,

(C) decreases the thermal conductivity,

(D) increases the density

(E) improves the toughness..

10.The room temperature tensile stress-strain curves in Figure 4.35 are for LAS-SiC fibre composites. The break-down of linearity in the curves at the point marked M is due to C （A）plastic deformation associated with dislocation motion,

(B)fracture of the fibres,

(C)matrix microcracking,

(D)viscous flow of a glassy phase,

(E)fibre pull-out.

11.Chemical vapour deposition of a carbon matrix BE

(A) is also commonly known as gas carbonization,

(B) is also commonly known as chemical vapour infiltration,

(C) produces a brittle composite with a glassy matrix,

(D) is independent of deposition pressure,

(E) is dependent on deposition temperature.

9.ABE;10.C;11.BE

Indicate whether statements 1 to 7 are true or false.

1.Polyester(聚酯) and epoxy（环氧） are examples of thermosets

(A)true

(B)false

2.Phenolic resins known as resoles or one-stage resins require the addition of

a curing agent prior to fabrication.

(A) true

(B) false