Code No: R05421801

SET-1

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JAWAHARLAL NEHRU TECHNOLOGY UNIVERSITY, HYDERABAD R05 IV B.Tech. II Semester Regular Exams, April/May – 2009 COMPOSITE MATERIALS (Metallurgy and Material Technology) Time: 3 hours Max. Marks.80 Answer any Five questions All questions carry equal marks ---

What are the functions of a matrix in composite materials? Why do materials and composite manufacturing processes go hand in hand? [8+8]

2.a)

Differentiate between thermal expansion molding and bag molding process mentioning their advantages and applications? What is the advantage of textile performing in composite processing? [8+8]

b) 3.

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1.a) b)

Write short notes on the following: a) Metal matrix composites. b) Fiber reinforced composites.

[8+8]

What is the selection criterion for reinforcement of the composite material? Explain the requisites of the matrix material in detail. [16]

5.a) b)

Give examples and applications of particulate reinforced composites. Outline the importance of composites as a substitute for conventional materials with suitable examples. [8+8]

6.

With a neat sketch discuss in detail the mechanism of direct oxidation of molten metal in the Directed Metal Oxidation process? [16]

7. a) b)

Compare and contrast the PAN carbon fibers and pitch carbon fibers. What are the benefits of using Composite Materials? Explain with suitable examples. [8+8]

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4.

Discuss the mechanics of load transfer from the matrix to fiber in the case of fiber is in elastic and matrix is a plastic stage. [16]

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8.

Code No: R05421801

SET-2

JAWAHARLAL NEHRU TECHNOLOGY UNIVERSITY, HYDERABAD R05 IV B.Tech. II Semester Regular Exams, April/May – 2009 COMPOSITE MATERIALS (Metallurgy and Material Technology) Max. Marks.80 Answer any Five questions All questions carry equal marks ---

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Time: 3 hours

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1. What do you exactly mean by ‘Composite Material’? What advantages does it possess compared to the conventional materials? [16] 2. Write short notes on the following: i) Requisites of matrix ii) Requisites of reinforcements iii) Applications of composite materials iv) Functions of reinforcements 3.a) b)

[16]

What are the different types of matrices and fibers used in Polymer Matrix composites? Explain them in detail. Write a detailed note on fabrication of advanced composites. [16] Discuss Metal-Matrix composites with examples. Write a note on properties and applications of Whisker fibers.

5.

What are long fibers? Discuss the effects of continuous fibers reinforcement in MMCs. [16]

6.a) b)

Write a note on limitations of the Lanxide process? Give examples and applications of particulate reinforced composites.

[8+8]

7.a) b)

Compare and contrast the carbon fibers and boron fibers. Discuss the influence of fiber length on the composite properties.

[8+8]

8.

For a continuous and oriented fiber-reinforced composite, the moduli of elasticity in the longitudinal and transverse directions are 19.7 and 3.66 GPa respectively. If the volume fraction of fibers is 0.25 determine the moduli of elasticity of fiber and matrix phases. [8+8]

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4.a) b)

[16]

SET-3

Code No: R05421801 JAWAHARLAL NEHRU TECHNOLOGY UNIVERSITY, HYDERABAD R05 IV B.Tech. II Semester Regular Exams, April/May – 2009 COMPOSITE MATERIALS (Metallurgy and Material Technology)

Max. Marks.80 Answer any Five questions All questions carry equal marks ---

b) 2.

‘Combination of two different materials would result into a better material’ Justify the statement with suitable examples. [16] Write a detailed note on the properties of composite materials? Write notes on the following: a) Boron fibers b) Metal oxide Fibers c) Cermets.

[8+8]

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1.a)

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Time: 3 hours

[16]

Describe the classification of metal matrix composites. Write short note on properties and applications of Glass fibers and Kelvar fibers. [16]

4.a) b)

Write a note on limitations of the Lanxide process? Give examples and applications of particulate reinforced composites.

5.

Write a note on types of fabrication processes used for manufacturing of MMCs. [16]

6.

What is barrier? Why it is used and list out the types of barriers used in the Directed Metal oxidation process? [8+8]

7.a) b)

Distinguish between carbon fibers and organic fibers. Write in detail about the classification of reinforcement materials.

8.

It is necessary to fabricate an aligned and discontinuous carbon fiber-epoxy matrix composite having a longitudinal tensile Strength of 1900 MPa using 0.45 volume fraction of fibers. Compute the required fiber fracture strength assuming that the average fiber diameter and length are 8x10-3 mm and 3.5mm respectively. The fiber-matrix bond strength is 40 MPa and the Matrix stress at fiber failure is 12 MPa. [8+8]

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3.a) b)

[8+8]

[8+8]

SET-4 Code No: R05421801 JAWAHARLAL NEHRU TECHNOLOGY UNIVERSITY, HYDERABAD R05 IV B.Tech. II Semester Regular Exams, April/May – 2009 COMPOSITE MATERIALS (Metallurgy and Material Technology) Max. Marks.80 Answer any Five questions All questions carry equal marks ---

.in

Time: 3 hours

With suitable examples, explain the classification of composite materials. Write in detail about the classification of reinforcement materials. [8+8]

2.

What are the selection criteria for Matrix of the composite material? Explain the requisites of the matrix material in detail. [16]

3.a) b)

Write short note on structural composites. Discuss Metal-Matrix composites with examples.

[8+8]

4.

Discuss the following: i) Filament winding method ii) Reaction injection moulding iii) Cladding.

[16]

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1.a) b)

With a neat sketch give details of the Dural can process for MMCs fabrication. [16]

6.a)

Discuss the advantages, limitations and applications of Directed Metal oxidation process. Draw neat sketches to show: i) Fiber ii) Particulate and iii) Laminar composites and indicate the different constituents in each case. [8+8]

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b)

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5.

Compare and contrast the carbon fibers and glass fibers. Discuss the functions of matrices.

8.

Write a note on reinforcement efficiency of fiber – reinforced composites with reference to fiber orientation and directions of stress applications. [8+8]

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7.a) b)

[8+8]