Kaniyur, Coimbatore – 641 659 (Affiliated to Anna University, ISO 9001 : 2008 Certified) (Approved by AICTE, Accredited by National Board of Accreditation, Accredited by NAAC)
DEPARTMENT OF AERONAUTICAL ENGINEERING
MODEL TEST COMPOSITE MATERIALS AND STRUCTURES (AE2451) Department
Year
Section
AERO
IV
A&B
Date 12.04.2016 (FN)
Duration: 3 Hours Maximum: 100 Marks PART A
(Answer All Questions)
(10 X 2 = 20)
2
What are the major constituents in composite materials? Define a laminate?
3
List down the reinforcement materials and resins used in composite materials.
4
What is the difference between isotropic and anisotropic material?
5
What is major Poisson’s Poisson’s ratio? ratio?
6
How local and global stresses are related? Define cross ply laminate and angle ply laminate.
1
7 8 9 10
What is strength ratio? List down the advantages using a sandwich construction. What is pre-preg? PART B
11
a
(Answer All Questions)
( 5 X 16 = 80)
(i) Discuss the classifications and different applications of composite materials (ii) State State the generalized Hooke’s law law applied for composite materials and explain.
(10) (6)
OR
11
12
For a graphite/epoxy unidirectional lamina, find the following. (a) Compliance matrix. (b) Minor poisons ratio. b (c) Reduced stiffness matrix. (d) Strains in the 1-2 co-ordinate system if the applied stresses are σ1 =2MPa, σ2= -3MPa, τ12= 4MPa, E1=181GPa, E2=10.3 GPa, ν GPa, ν12 =0.28, G12=7.17 GPa.
a
(i) Discuss (1) Tensile (2) Impact behavior of composites with suitable examples. (ii) Discuss about fiber reinforced and particle reinforced composites and compare them.
(16)
(10) (6)
OR 12
b Explain the elasticity approach to find four different elastic moduli .
(16)
13
(i) With the help of illustrations , explain the different failure criteria for composites a (ii) Explain the construction, properties and applications of angle ply laminates.
(10) (6)
OR
13
b Compare Tsai-Hill theory and Tsai-Wu theory along with the limitations if any.
14
(i) Obtain an expression for the flexural modulus modulus of a (1) Sandwich plate with different face thickness. a (2) Sandwich plate with different face thickness and material.
(16)
(16)
OR
(i) Describing the various methods of fabricating sandwich panels. Also compare their merits b and limitations. (16)
15
a
(i) Explain open and closed mould processes. processes. (ii)Explain with neat sketches one fabrication process under each method.