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Wednesday, 7 January 2015

Non-Destructive Test and Evaluation of Materials-Model question paper for B.E/B.Tech Engineering


1(a) Write a note on the factors influencing the reliability of Non-Destructive Test and Evaluation. (6 Marks)
(b) Write a note on selection of radiation source in radiographic method of NDT. (4 Marks)
(c) Briefly explain the principle involved in X-ray computed tomography. (4 Marks)
(d) What are the three basic means used as protective measures to keep radiation exposure within allowable limits? Explain. (6 Marks)
2(a) Distinguish between Symmetric Lamb waves and Asymmetric Lamb waves. (6 marks)
(b) Define Acoustic Impedance. Mention the parameters on which acoustic impedance is dependant. (4 Marks)
(c) Explain how ultrasonics are generated by piezo electric effect. (6 Marks)
(d) Write a note on variables affecting ultrasonic test. (4 Marks)
3(a) Explain how wrought products are tested by ultrasonic method. (8 Marks)
(b) Write a note on British Calibration Block. (4 Marks)
(c) Explain distance-amplitude curve method for the determination of flaw size. (4 Marks)
(d) Write a note on limitations of ultrasonic testing. (4 Marks)
4(a) A liquid with high surface tension, low contact angle and low viscosity makes a good penetrant liquid. Explain. (6 Marks)
(b) Write a note on pre-cleaning the component surface in the liquid penetrant test process. (4 Marks)
(c) Explain propagative and non-propagative surface defects. (4 Marks)
(d) What are the four types of developers used in liquid penetrant test process. Explain. (6 Marks)
5(a) Explain the various methods involved in magnetic particle test. (8 Marks)
(b) Write a note on the defects and their observed indications during magnetic particle test. (8 Marks)
(c) Write a note on limitations of magnetic particle test.(4 Marks)
6(a) What is magnetic coupling? What are the two types of coupling? (6 Marks)
(b) Write a note on the effect of magnetic permeability on impedance diagram. (6 Marks)
(c) What is the role of encircling coil and surface coil in eddy current test system? (8 Marks)
7(a) Draw and explain a typical Acoustic Emission setup. (6 Marks)
(b) Distinguish between Colorometric  method of tracer gas test and Helium mass spectroscopy. (6 Marks)
(c) What is pulse-echo method? Explain. (4 Marks)
(d) Write a short note on coin tap test. (4 Marks)
8 (a) Explain how NDE is useful in aerospace industries. (6 Marks)
(b) Write a note on probability of defect detection and NDE. (6 Marks)
(c) Write a note on modern trends in NDE. (8 Marks)

Tuesday, 6 January 2015

Theory of plasticity-Model question paper for B.E/B.Tech Engineering



1(a) Explain the theories of elastic failure and give their limitations.(6 Marks)
(b) Explain the strain hardening phenomenon. What is the effect of strain hardening on plastic deformation? (6 Marks)
(c) Explain the Saint-Venant’s theory of plastic flow in detail. What are the limitations of this theory? (8 Marks)
2(a) Explain the two yield criterias in two-dimensional applications. (6 Marks)
(b) Derive the Siebel formula for the stress distribution in the neck of a tensile specimen. (8 Marks)
(c) A tensile test specimen of original diameter 15 mm is pulled in tension and the following observations are made:
P=150 kN, a=0.6 cm, R=2cm.
Calculate the corrected flow stress at this particular stage of deformation and the corresponding effective strain. (6 Marks)
3(a) Explain the sand-heap analogy for solving plastic torsion problems. How this analogy is modified for sections having one or more holes? What are the limitations of this analogy? (10 Marks)
(b) Write a short note on Tresca’s yield condition. (4 Marks)
(c) A simply supported beam of width 15 cm and depth 20 cm is 5 m long. It carries two equal loads at 1m from each end. If the yield stress for the beam material is 225 MPa, draw the residual stress distribution in the beam if (i) the outer 3 cm shall is to yield, and (ii) the whole of the beam is to yield. (6 Marks)
4(a) Derive Geiringer’s continuity equations. (8 Marks)
(b) What do you understand by a slip-line? How slip-line nets can be drawn? (6 Marks)
(c) A solid circular cylinder of radius 20 cm is rotated so that yielding sets in. Determine the speed of rotation assuming s0= 150N/mm2, r=7.8 g/cm3 (4 Marks)
5(a) What is the role of coefficient of friction in metal forming? How this can be estimated? (6 Marks)
(b) What is the difference between homogeneous and non-homogeneous deformation? Explain briefly. (6 Marks)
(c) Derive an equation for the drawing stress at the exit section with a cylindrical moving mandrel and with back stress applied. (8 Marks)
6(a) Determine and discuss the forces on the rolls of a four-high rolling mill when the work rolls are driven by the motor. (6 Marks)
(b) Derive an expression for average pressure during closed die forging with overlapping dies. Modify this expression for axial symmetry. (7 Marks)
(c) List the advantages of closed-die forgings over open-die forgings. (4 Marks)
(d) Calculate the bite angle when rolling plates 15mm thick using work rolls 400 mm diameter and reducing the thickness by 3mm. (3 Marks)
7(a) Derive the expression for the draw stress for tube sinking with a conical die. (6 Marks)
(b) What is deep drawing? Derive formula to calculate the radial stress in deep drawing with friction. (8 Marks)
(c) A cylindrical cup without flange is to be drawn from a 2mm thick duralumin sheet. The cup shall have diameter of 15mm and height of 40mm. Reduction ration in first draw and in subsequent draws may not exceed 40% and 155 respectively.  Determine the blank size and the number of draws necessary. (6 Marks)
8(a) Explain the gas mixture process of metal forming. What are its characteristics? (4 Marks)
(b) What are the various methods of solving finite-difference equations? Explain briefly. (6 Marks)
(c) State and prove The Castigliano’s first and second theorems. (6 Marks)
(d) Write a short note on dynamic plasticity. (4 Marks)