Download AKTU B-Tech 8th Sem 2016-17 NME061 Experimental Stress Analysis Question Paper

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B.TECH.

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THEORY EXAMINATION (SEM–VIII) 2016-17

EXPERIMENTAL STRESS ANALYSIS

Max. Marks : 100

Note: Be precise in your answer. In case of numerical problem assume data wherever not provided.

SECTION – A

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1. Explain the following:
   1. What do you mean by Principal plane and Principal stresses?
   2. What is null balancing wheat stone bridge circuit?
   3. Define stress optic law.
   4. State the method of calibrating of strain gage.
   5. What are the requirements in selection of Photo elastic materials?

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   6. How will you obtain dark and light field in a circular polariscope?
   7. Enumerate the various Non-Destructive Testing (NDT) methods?
   8. What is a stress gauge?
   9. In what way three dimensional photo elasticity is different from two-dimensional photo elasticity?
   10. Briefly explain Isochromatic Fringe Pattern.

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   10 x 2 = 20

SECTION - B

Attempt any five parts of the following questions:

1. 1. Derive an expression for change in output voltage of wheat stone bridge circuit in terms of the changes in resistances.

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   2. Explain in detail the working principle and measurement of strains from an Acoustical strain gauge with neat sketch.
   3. What in energy absorbed by a system, complementary strain energy and elastic strain energy? Explain these with the help of diagram.
   4. What is significance of strain compatibility equation? Write down these compatibility equations.
   5. Derive an expression for output OSC voltage of whetstone bridge circuit for strain gauges when all the gauges are active. Calculate the sensitivity when all Given R? = 120 ohms, Ig = 50 mA, Sg = 2.
   6. What are strain rosettes? What are their uses? For a rectangular rosette on a steel specimen ? €x = -600 ? 10-6, €? = 300 ? 10-6, €c = 400 x 10-6. Determine the principal strains, principal stresses and directions Esteel = 210 Gpa.

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   7. Derive expressions for: (i) minimum and maximum stresses and strains, (ii) angle of principal stress, (iii) shear stress in each case

   5 x 10 = 50

SECTION - C

Attempt any two parts of the following questions:

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1. 1. Why do we require separation? Explain any two-separation techniques in detail.
   2. Explain in detail how stress-freezing technique is employed in three-dimensional Photoelasticity?
2. Explain the following:
   1. Ultrasonic testing in NDT and their applications.
   2. Radiography

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3. 1. Explain with necessary equations how isoclinics are eliminated in circular polariscope setup. What are the properties of isochromatics?
   2. Explain any two compensation techniques used in Photoelasticity

2 x 15 = 30

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