Code No: 53204/MT

M.Tech. – II Semester Regular Examinations, September, 2

EXPERIMENTAL STRESS ANALYSIS (Machine Design)

Time: 3hours Max. Mark

Answer any FIVE questions All questions carry equal marks

- - - 1.a) Explain clearly what do you understand by:

i) Plane stress problem ii) Plain strain problem.

b) Given the displacement field: 4 2 2 33 2u x x y x y z= + + + + + 4

2 2 3 2 22 1v xy y y z z= + + + + 2 22 2w x xy yz zx y z= + + + + + + Compute the associated strain at the point (2, 2, 2). 2.a) Derive an expression for the gauge factor of an electrical res

strain gauge. b) Describe with sketches wise type and foil type electrical res

strain gauges. 3.a) For recording strain-time curves explain when the fo

recording devices are used. i) Oscillograph ii) Cathod ray oscilloscope.

b) With the help of a sketch explain the operating principle of writing oscillograph.

4.a) State the advantages and limitations of the brittle coating m

of experimental stress analysis. b) Discuss briefly the factors affecting the behaviour of stress c

5.a) Explain Moire method of whole field strain analysis.

b) Briefly discuss the advantages of Moire fringe technique.

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Code No: 53204/MT ::2:: 6.a) Discuss the requirements of an ideal photoelastic model material

for two dimensional photo elasticity. b) Discuss the effect of a stressed photoelastic model in a plane Polariscope.

7.a) Explain briefly the shear difference method in three dimensions. b) Write a note on slicing a model and interpretation of the resulting

fringe pattern in three dimensional photo elasticity. 8. Write short notes on the following:

i) Bire fringent coatings ii) Fringe order determination in birefringent coatings iii) Cross sensitivity of an electrical resistance strain gauge. iv) Isochrometic and Isoclinics.

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