Roll No. B.E / B.Tech ( Part Time ) DEGREE END SEMESTER EXAMINATIONS, APRIL / MAY Mechanical Engineering. Third Semester

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1 Roll No. B.E / B.Tech ( Part Time ) DEGREE END SEMESTER EXAMINATIONS, APRIL / MAY 2014 Mechanical Engineering Third Semester PTME232/PTME281/PTME9203 KINEMATICS OF MACHINES (Regulation 2002/2005/2009) Time: 3 Hours Answer ALL Questions Max. Marks Explain Kutzbach criterion? PART-A (10 x 2 = 20 Marks) Classify Kinematic pairs according to the type of contact between the elements? Explain Coriolis component of acceleration? 4. A point B on a rigid link AB moves with respect to A with angular velocity a> rad/sec. What is the radial component of the acceleration of B with respect to A? 5. What are the different types of motion with which a follower can move? 6. Define the following in cams : i. pitch curve ii. Pressure angle 7. State the law of gearing? 8. What do you understand by the term 'interference' as applied to gears 9. State the laws of friction? 10. Explain the phenomena of 'slip' and 'creep' in a belt drive? Part- B(5x16 = 80 marks) 11. Construct the profile of a cam to suit the following specifications Cam shaft diameter=40mm, least radius of cam=25mm, diameter of roller=25mm, Angle of lift=1200, Angle of fall=1500; lift of the follower=40mm, Number of pauses are two of equal interval between motions. During the lift the motion is SHM. During the fall the motion is uniform acceleration and deceleration. The speed of the cam shaft is uniform. The line of stroke of the follower is off-set 12.5mm from the center of cam. 12. a) (i) Explain Kinematic Inversion with examples? (8 Marks) (ii)explain Whitworth quick return motion mechanism? (8 Marks) b) Explain the following : (i) lower and higher pairs with examples (4 marks) (ii) Grubler criterion for planar mechanism (4 marks) (iii) In a crank and slotted lever quick return motion mechanism, the distance between the fixed centers is 240mm and the length of the driving crank is 120mm. Find the inclination of the slotted bar with the vertical in the extreme position and the time ratio of cutting stroke to the return stroke. (8 marks)

2 13. a) A mechanism as shown in fig has the following dimensions: OA=200mm; AB=1.5m; BC=600mm; CD=500mm and BE=400mm. Locate all the instantaneous centers. If the crank OA rotates uniformly at 120 rpm clockwise, Find (1) the velocity of B, C, and D (2) the angular velocity of the links AB, BC and CD m 10 mm b) In the mechanism shown in Fig, the slider C is moving to the right with a velocity of 1 m/s and an acceleration of 2.5 m/s 2.The dimensions of various links are AB = 3 m inclined at 45 with the vertical and BC = 1.5 m inclined at 45 with the horizontal. Determine: 1. The magnitude of vertical and horizontal component of the acceleration of the point B, and 2. the angular acceleration of the links AB and BC. A C %Jjt Hi 14. a) Two involute gears of 20 pressure angle are in mesh. The number of teeth on pinion is 20 and the gear ratio is 2. If the pitch expressed in module is 5 mm and the pitch line speed is 1.2 m/s, assuming addendum as standard and equal to one module, find: 1. The angle turned through by pinion when one pair of teeth is in mesh; and 2. The maximum velocity of sliding. b) Fig shown below is an epicyclic gear train in which gear A drives the internal gear D through compound gears B and C. The number of teeth on gear A is 20 and center distance between the centers of gears A and B is 300mm. If the module of all gears is 10mm and gear c has 30 teeth. Find the speed of gear D. The arm rotates at 600 rpm in counter clockwise direction and gear A is fixed.

3 15. a) A dry single plate clutch is to be designed for an automotive vehicle whose engine is rated to give 100 kw at 2400 r.p.m. and maximum torque 500 N-m. The outer radius of friction plate is 25% more than the inner radius. The intensity of pressure between the plates is not to exceed 0.07 N/mm2. The coefficient of friction may be assumed equal to 0.3. The helical springs required by this clutch to provide axial force necessary to engage the clutch are eight. If each spring has stiffness equal to 40 N /mm, determine the initial compression in the springs and dimensions of the friction plate. b) Two pulleys, one 450 mm diameter and the other 200 mm diameter are on parallel shafts 1.95 m apart and are connected by a crossed belt. Find the length of the belt required and the angle of contact between the belt and each pulley. What power can be transmitted by the belt when the larger pulley rotates at 200 rev/min, if the maximum permissible tension in the belt is 1 kn, and the coefficient of friction between the belt and pulley is 0.25?

4 Roll No. B.E / B.Tech (Part Time ) DEGREE END SEMESTER EXAMINATIONS, APRIL / MAY 2014 B.E. MECHANICAL ENGINEERING (Part-Time) 3 rd Semester PTMNN281/ PTME9252 ENGINEERING MATERIALS AND METALLURGY (Regulation 2005 / 2009) Time: 3 Hours Answer ALL Questions Max. Marks Classify the plain carbon Steel 2. What is eutectoid reaction? 3. Define solute and solvent 4. What is induction hardening? 5. What are HSLA steel? PART-A (10 x 2 = 20 Marks) 6. What is the purpose of magnesium treatment in producing S.G. iron? 7. What are engineering ceramics? 8. What is a composite? 9. List the parameters that can be determined from the tensile test 10. What is a fracture? Part - B ( 5 x 16 = 80 marks) 11. Draw Fe-Fe3C phase diagram and label all the phases. Discuss the structural transformation while cooling from liquid to solid. 12. a) Explain: 1. Annealing (4) 2. Spheroidising (4) 3. Normalizing (4) 4. Hardening (4) b) Discuss the classification, micro structure properties and application of steel

5 13. a) Write short notes on: (i) Austinitic stainless steel (8) (ii) Ferritic stainless steel (8) b) Discuss the composition, properties & typical application of some aluminum alloys 14. a) Write short notes about the different types of matrix materials and reinforced materials used to make polymers matrix composites. b) Describe the molecular structure, properties and application of the following polymers. (i) Polyvinyl chloride (PVC) (ii) Polystyrene (PS) 15. a) (i)draw creep curve and explain the different stages of creep damage (ii) Explain Brinell hardness testing and its applications b) (i) Discuss characteristics of ductile fracture and brittle fracture (8). (ii)explain the testing procedure of Izod impact test (8)