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Code: 15A03803
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B.Tech IV Year II Semester (R15) Advanced Supplementary Examinations July 2019
COMPOSITE MATERIALS
(Mechanical Engineering)
Time: 3 hours
Max. Marks: 70
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PART - A
(Compulsory Question)
Answer the following: (10 X 02 = 20 Marks)
- Define composite materials.
- Write any four applications of composite materials.
- How is FRP made?
- Write the compliance matrix for orthotropic material.
- Define void in composite material.
- What is unidirectional composite?
- How do composite laminates behave under load?
- State the assumptions made in thin plate theory.
- What is balanced laminate?
- Write the equation of Tsai-Hill theory of composite material.
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PART - B
(Answer all five units, 5 X 10 = 50 Marks)
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UNIT - I
- (a) Discuss briefly the desirable characteristics of fiber in a fiber reinforced composites.
(b) Write a brief note on engineering applications of composites.
OR - List and explain the properties and applications of:
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(a) Glass fibers.
(b) Carbon fibers.
UNIT - II
- With suitable sketches, explain the following methods of manufacturing PMC's:
(a) Filament Winding.--- Content provided by FirstRanker.com ---
(b) Hand Lay-Up.
OR - Write generalized Hooke's law in matrix form. Deduce the stiffness matrix & compliance matrix for a lamina from generalized Hook's law.
UNIT - III
- Derive the expressions to E11, E22, Y12 and G12 in terms of constituent properties using micromechanics principles.
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OR - (a) Mention the assumptions made in the mechanics of material approach model to determine the four elastic moduli.
(b) Find the longitudinal elastic modulus of a unidirectional glass/epoxy lamina with a 70% fiber volume fraction. Also find the ratio of the load taken by the fibers to that of the composite. Take Ef = 85 GPa, Em = 3.4 GPa.
UNIT - IV
- Derive the constitutive relations for a multidirectional composite in a hygrothermal environment.
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OR - What is lamination theory? Describe with a sketch of laminate stacking sequence code.
UNIT - V
- What is Tsai-Hill criterion? Explain.
OR - Check the failure of a unidirectional lamina with Tsai-Wu failure criterion using the following properties:
s1 = 800 MPa, s2 = 300 MPa, s12 = 50 MPa
X11 = 1500 MPa, X'11 = -1250 MPa, X22 = 50 MPa
X'22 = -200 MPa, X12 = -100 MPa.
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This download link is referred from the post: JNTU Anantapur B-Tech 4-2 last 10 year question papers 2010 -2020 -All regulation- All branches- 4th Year 2nd Sem
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