understood

1. EGYPTIAN ACADEMY FOR ENGINEERING
& ADVANCED TECHNOLOGY
1
Advanced materials
Quiz (1)
(1) Choose the most correct answer
1- ……….. have very large molecular structures, often chain-like in nature
that have a backbone of carbon atoms and are unreactive in a large number
of environments
(a) Epoxy (b) Steel
(c) Aluminum oxide (Al2O3) (d) Silicon carbide (SiC)
2- A composite material which composes of 85 wt% of aluminum (Al) and 15
wt% of boron carbide (B4C) can be considered:
(a) Metal matrix composite. (b) Ceramic matrix composite.
(c) Polymeric matrix composite (d) None of the previous
3- Which of the following statements is not true?
(a) large-particle composite is considered a subclassification of particle-
reinforced composites.
(b) Large -particle composites can be treated on the atomic or molecular
level
(c) Large particle phases are harder and stiffer than the matrix
(d) All the previous are true statements.
4- For some glass fiber-epoxy matrix combination, the critical fiber length
fiber diameter ratio is 50. Given that the tensile strength of glass fibers is
3.45 GPa, the fiber- matrix bond strength is……..
(a) 34.5 MPa (b) 50.6 MPa (c) 23.5 MPa (d) 40.6 MPa
5- For a continuous and oriented fiber-reinforced composite, the moduli of
elasticity in the longitudinal direction is 19.7 GPa . If the volume fraction of
fibers is 0.25 and the modulus of elasticity of the matrix equals to 2.79 GPa.
then the modulus of elasticity of the fibers will equal to……GPa
(a) 60.4 (b) 70.4 (c) 50.4 (d) None of the previous

2. EGYPTIAN ACADEMY FOR ENGINEERING
& ADVANCED TECHNOLOGY
2
6- In fiber reinforced composites, this fiber–matrix bond ……… at the fiber ends
(a) Increases (b) decrease (c) does not change
(d) none of the previous
7- In fiber reinforced composites, the mechanical strength of the composite
mainly depends on:
(a) The phase volume fractions of both the fibers and matrix.
(b) The direction in which the stress or load is applied.
(c) The stress–strain behaviors of fiber and matrix phases.
(d) All the above.
8- Fiber reinforced composites' failure begins at a strain equals to….
(a) εm
*
(b) 0.5 εm
*
(c) εf
*
(d) 0.5 εf
*
Mustafa Shaban Afifi
2018044