Roll No__________________

KUMARAGURU COLLEGE OF TECHNOLOGOY, COIMBATORE – 641 049Department of Aeronautical

Internal Test – I Semester -7

Degree & Branch: B.E & Aeronautical Engineering Date : 23-7-2015Sub Code & Name AER118 & Composite Materials & Structures Time: FN

Duration: Two hrs Maximum Marks: 50

PART A (Answer All the Questions) (10 x 1 = 10 Marks)

1. Most common shape of fibre used is(a) Rectangular (b

)square

(c)

circular (d)

triangular

2. Silicon Nitride is a(a)

Ceramic Matrix Material (b)

metal Matrix Material

(c) Polymer Matrix Material (d)

Calcium borosilicate

3. The factors affecting fiber performance in the composite is(a) Orientation (b

)length

(c) Shape (d)

All of the above

4. Aspect ratio of fiber is(a)

Length to diameter ratio (b)

Length to breadth ratio

(c) Length to cross sectional area ratio (d)

Length to circumference ratio

5. E-type glass fiber is generally referred to as(a) Magnesia alumino silicate glass (b

)Lime alumino silicate glass

(c) Alumina glass (d)

Magnesium glass

6. S-type glass fiber is generally referred to as(a)

Magnesia alumino silicate glass (b)

Magnesium glass

(c) Alumina glass (d)

Lime alumino silicate glass

7. The elastic constant for anisotropic material

(a)

21 (b)

12

(c) 9 (d)

2

8. The micro mechanical analysis of a lamina is based on ------ properties

(a)

Average (b)

Maximum

(c) Minimum (d)

Central

9. Glass epoxy is a(a) Ceramic Matrix Material (b

)Metal Matrix Material

(c)

Polymer Matrix Material (d)

Calcium borosilicate

10. Aluminium is a example for(a)

Isotropic (b)

Anisotropic

(c) Orthotropic (d)

None of these

PART B (5x2 = 10 Marks)11. What is a composite material? List the advantages of composites?

12. Why epoxy resin is used in aerospace industry?

13. What is an anisotropic and orthotropic material?

14. What are the assumptions for mechanics of materials approach?

15. What is micromechanics and classify?

PART C (3x10 = 30 Marks)(Answer any Three Questions)

16. How composites are classified? What is Reinforcement?

17. Derive the expression for generalized Hooke’s law?

18. Explain the stiffness matrix and compliance matrix for different material? List the disadvantages

of composites?

19. Explain the MOM approach to find 4 elastic constant?

20. For a glass epoxy composites Ef =80GPa, Em=3.5GPa, γf =.25, γm =.25. find the minor

poisson ratio,E1,E2, G12, for a fibre volume fraction of 60%? List the applications of

composites?