Theory of Machines 1 - Jun 2015
Mechanical Engg (Semester 4)
TOTAL MARKS: 100
TOTAL TIME: 3 HOURS (1) Question 1 is compulsory.
(2) Attempt any four from the remaining questions.
(3) Assume data wherever required.
(4) Figures to the right indicate full marks.
Answer any one question from Q1 and Q2
1 (a) Define 'Inversion'. Explain with the help of neat sketches any two inversions of double slider crank chain.(5 marks) 1 (b) Write a note on 'Dynamically Equivalent System'.(5 marks) 2 (a) Compare 'Davis' and 'Ackermann' Steering Gear Mechanisms.(4 marks) 2 (b) With the help of neat schematic diagram, derive frequency equation of bifilar suspension system.(6 marks)
Answer any one question from Q3 and Q4
3 (a) Determine the dimensions of the contact surfaces of cone clutch, for the following specifications:
(i) Power transmission capacity = 20 kW
(ii) Speed = 1600 RPM
(iii) Cone angle = 30°
(iv) Maximum intensity of pressure = 0.8 ? 10 5 N/m2.
(v) Coefficient of friction = 0.3
(vi) Mean radius is twice the width of the friction surface.
Assume uniform wear condition.(5 marks) 3 (b) Explain Complex Algebra method of acceleration analysis for a binary link.(5 marks) 4 (a) Describe with neat sketch the construction and working of epicyclic train type dynamometer.(5 marks) 4 (b) Derive an equation for velocity of piston in an I.C. engine mechanism, when crank rotates with uniform angular velocity using analytical method.(5 marks)
Answer any one question from Q5 and Q6
5 (a) State and explain Kennedy's theorem.(4 marks)
5 (b) In the mechanism shown in Fig. 1, the crank OA rotates at 20 RPM in anticlockwise direction and gives motion to the sliding blocks B and D. For the given configuration of mechanism, determine by relative velocity method and relative acceleration method:
(i) Velocity of sliders B and D
(ii) Angular velocity of link CD
(iii) Acceleration of sliders B.
OA = 300 mm, AB = 1.2 m, BC = CD = 450 mm (11 marks) 6 (a) With the help of neat sketch, explain the concept of 'Velocity Image Principle'.(4 marks) 6 (b) In the mechanism shown in Fig. 1 the crank OA rotates at 20 RPM in anticlockwise direction and gives motion to the sliding locks B and D. For the given configuration of mechanism, locate all instantaneous centres of rotation, then determine:
i) Velocity of sliders B and D
ii) Angular velocities of links AB and CD.(11 marks)
Answer any one question from Q7 and Q8
7 (a) What is Coriolis acceleration ? Find the direction of this acceleration in the case shown in Fig. 2.
7 (b) The crank of an engine is 180mm long and obliquity ratio
is 4. Determine the velocity and acceleration of the piston,
when the crank is turned through 40° from I.D.C. position for the following two cases:
(i) The crank rotates at a uniform speed of 300 RPM
(ii) The crank rotates at a speed of 300 RPM and is increasing at the rate of 120 rad/s2.(11 marks) 8 (a) Explain the procedure to construct Klein's construction to determine the velocity and acceleration of a piston an I.C. engine mechanism, when crank rotates at a uniform angular velocity.(4 marks) 8 (b) The driving crank AB of length 75 mm for the quick return mechanism, as shown in Fig. 3 revolves at a uniform speed of 200 RPM. Find acceleration of point Q, for the configuration shown, when the crank makes an angle of 60° with the vertical line of centres PA. (11 marks)