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
Date 12.04.2016 (FN)
Duration: 3 Hours Maximum: 100 Marks PART A
(Answer All Questions)
(10 X 2 = 20)
What are the major constituents in composite materials? Define a laminate?
List down the reinforcement materials and resins used in composite materials.
What is the difference between isotropic and anisotropic material?
What is major Poisson’s Poisson’s ratio? ratio?
How local and global stresses are related? Define cross ply laminate and angle ply laminate.
7 8 9 10
What is strength ratio? List down the advantages using a sandwich construction. What is pre-preg? PART B
(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.
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.
(i) Discuss (1) Tensile (2) Impact behavior of composites with suitable examples. (ii) Discuss about fiber reinforced and particle reinforced composites and compare them.
b Explain the elasticity approach to find four different elastic moduli .
(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.
b Compare Tsai-Hill theory and Tsai-Wu theory along with the limitations if any.
(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.
(i) Describing the various methods of fabricating sandwich panels. Also compare their merits b and limitations. (16)
(i) Explain open and closed mould processes. processes. (ii)Explain with neat sketches one fabrication process under each method.