Download JNTUA B.Tech 4-2 R13 2018 July Supple 13A03803 Composite Materials Question Paper

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Code: 13A03803

B.Tech IV Year II Semester (R13) Advanced Supplementary Examinations July 2018

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COMPOSITE MATERIALS

(Mechanical Engineering)

Time: 3 hours Max. Marks: 70

PART - A

(Compulsory Question)

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Answer the following: (10 X 02 = 20 Marks)

1. (a) What are the applications of composite materials?
2. (b) Differentiate between thermoplastics and thermosets.
3. (c) What is pultrusion?
4. (d) Define strain energy.

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5. (e) Explain briefly about the ply architecture.
6. (f) Explain Hooke's law for a two dimensional unidirectional lamina.
7. (g) What are the assumptions made in developing stress strain relationships?
8. (h) Write the steps for analyzing a laminated composite subjected to the applied forces and moments.
9. (i) What is failure envelope?

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10. (j) Explain Tsai- Hill theory.

PART - B

(Answer all five units, 5 X 10 = 50 Marks)

UNIT - I

1. (a) Explain briefly various applications of FRP.

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2. (b) Explain briefly classification and characteristics of composite materials.

OR

1. (a) Explain particulate composites and polymer composites.
2. (b) Explain the basic terminology in fiber reinforced composites with examples.

UNIT - II

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4 What are the different types of fabrication methods of composites? Explain die molding.

OR

5 Find the compliance and stiffness matrix for a graphite/epoxy lamina. The material properties are given as: E1 = 181 GPa, E2 = 10.3 GPa, E3 = 10.3 GPa, V12 = 0.28, V23 = 0.6, V13 = 0.27 G12 = 7.17 GPa, G23 = 3.0 GPa, G31 = 7.0 GPa.

UNIT - III

6 Write stress - strain relations for a unidirectional lamina in terms of engineering constants referred to an arbitrary coordinate system (x, y).

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OR

7 Explain the basic approaches to the micromechanics of composite materials.

UNIT - IV

8 Explain the following:

1. (a) Warpage of laminates.

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2. (b) Hygrothermal effects in a laminate.

OR

9 Derive the effective in-plane engineering constants for a laminate.

UNIT - V

10 What are the different failure methods of composites? Explain.

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OR

11 Determine the first-ply failure strength of a [0/90]s laminate under uniaxial tension or compression based on: (i) The maximum stress criterion. (ii) Tsai-Wu criterion. (Assume any missing data)

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