Download JNTUA B.Tech 4-2 R15 2019 April Regular 15A03803 Composite Materials Question Paper

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Code: 15A03803

Max. Marks: 70

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Time: 3 hours

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B.Tech IV Year II Semester (R15) Regular Examinations April 2019

COMPOSITE MATERIALS

(Mechanical Engineering)

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PART - A

(Compulsory Question)

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

1. Define flake composites.
2. Define thermoplastics.

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3. What is pultruded in FRP?
4. Write the stiffness matrix for orthotropic material.
5. Define volume and mass fraction.
6. What is the primary function of the matrix in a composite material?
7. What is the importance of cross-ply laminates?

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8. What is lamination theory?
9. Write the equation of maximum stress failure criterion of composite materials.
10. What is failure envelop.

PART - B

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

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UNIT - I

1. Briefly describe the classification of composites.

   OR

2. With the help of a neat sketch, explain the production of fibers.

UNIT - II

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1. Explain the following methods of manufacturing PMC's with suitable sketches:
   1. Pultrusion.
   2. Prepregs.

   OR

2. Derive the stress-strain relations an orthotropic lamina in three dimensional domains in terms of engineering constants.

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UNIT - III

1. Derive the expressions to Y12 and G12 in terms of constituent properties using micromechanics principles.

   OR

2. Find the coefficient of thermal expansion for a 60° angle lamina of glass/epoxy whose longitudinal and transverse coefficients of thermal expansion are 8.6 X 10^-6 m/m/°C and 22.1 X 10^-6 m/m/°C respectively.

UNIT - IV

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1. Briefly explain inter laminar stresses in a laminate composites.

   OR

2. Write the assumptions of CLT and derive the stress strain relations for a classical laminate and represent the stress-strain variation in a laminate.

UNIT - V

1. What are the advantages of composites in structural design? Explain.

   OR

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2. Write short notes on the following:
   1. Maximum stress failure theory.
   2. Failure envelops.

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