GTU BE 7th Semester 170103 Mechanics of Composite Materials Summer 2018 Question Paper

1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE ? SEMESTER VII? ? EXAMINATION ? SUMMER 2018
Subject Code: 170103 Date: 03-05-2018
Subject Name: Mechanics of Composite Materials
Time: 02:30 pm to 05:00 pm Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) Define composite materials. Classify and explain types of composite materials. 07
(b) Define: Ply, Principal axis, Reference axis, In-plane stress, On-axis system,
Orthotropic material, Transversely isotropic material.
07

Q.2 (a) Describe and cite the applications of composites and their use in different
industries Explain in detail and with sketches the mechanical behaviour of
isotropic, orthotropic and anisotropic materials.
07
(b) Derive longitudinal strength of a lamina. 07
OR
(b) Explain strength and stiffness of composite materials and metals with
comparison.
07

Q.3 (a) Explain Maximum Stress theory. 07
(b) Define and explain a lamina and laminate with necessary sketches. 07
OR
Q.3 (a) Discuss, justify, sketch and derive the stress-strain behaviour over a laminate.
Also explain the need of tailoring FRPs.
07
(b) Explain transverse modulus and in-plane shear modulus. 07

Q.4 (a) Explain the stress and strain relations in a laminate and also explain and sketch
the variation of stress and strain through a laminate.
07
(b) Describe [A], [B] and [D] matrices and explain its importance. 07
OR
Q.4 (a) Write the types of local failure modes at micro-level. Explain longitudinal
tension.
07
(b) Write a short note on symmetric laminates. 07

Q.5 (a) Derive inplane-shear modulus and Poisson?s ratio for a uni-directional
composite.
07
(b) What do you mean by failure in materials? Explain the use of failure criteria. 07
OR
Q.5 (a) Write a short note on anti-symmetric laminates. 07
(b) Explain failure in transverse tension and compression. 07

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