B.Tech-B.Tech Mechanical Engineering Dynamics of Machinery (Sathyabama University, Chennai, Tamil Nadu-2012)
Monday, 19 August 2013 05:52Duraimani
(Established under section 3 of UGC Act,1956)
Course & Branch :B.E - AUTO/MECH
Title of the Paper :Dynamics of Machinery Max. Marks:80
Sub. Code :615401(2006-07-08-09) Time : 3 Hours
Date :05/11/2012 Session :AN
PART - A (10 x 2 = 20)
Answer ALL the Questions
1. Differentiate between static force analysis and dynamic force analysis.
2. What are the forces acting on the connecting rod?
3. Write the different types of balancing.
4. Define tractive force.
5. What is meant by free vibration?
6. Define frequency of vibration.
7. What is meant by degree of freedom?
8. What do you mean by damping and damped vibration?
9. Define torsional equivalent shaft.
10. Explain the Dunkerley’s method used in transverse vibration.
PART – B (5 x 12 = 60)
Answer ALL the Questions
11. In a reciprocating engine mechanism, the crank and the connecting are 300 mm and 1 mm long respectively and the crank rotates at the constant speed of 200 r.p.m. Determine analytically, the crank angle at which the maximum velocity occurs and the maximum velocity of the piston.
(or)
12. The radius of gyration of a flywheel is 1 meter and fluctuation of speed is not to exceed 1% of the mean speed of the flywheel, if the mass of the flywheel is 3340 kg and steam engine develops 150 kW at 135 rpm, then find
(a) Maximum fluctuation of energy, and
(b) Coefficient of fluctuation of energy
13. Four masses A, B, C, and D at equal radii and are equally spaced along a shaft. The mass B is 7 kg and the radii of C and D make angles of 90° and 240° respectively with a radius of B. Find the magnitude of masses A, C and D, and the angular position of A so that the system may be completely balanced.
(or)
14. The pistons of a 600 twin v engines has stroke of 120 mm, the connecting rods driving a common crank has a length of 200 mm. The mass of reciprocating parts per cylinder is 1 kg and the speed of the crank shaft is 2500 rpm. Determine the magnitude of the primary and secondary forces.
15. A spring mass system has spring stiffness ‘s’ N/m. and a mass of ‘m’ kg. It has the natural frequency of vibration as 12 Hz. An extra 2 kg mass is coupled to ‘m’ and Natural frequency reduces by 2 Hz. Find the values of ‘s’ and ‘m’.
(or)
16. A mass suspended from a helical spring vibrates in a viscous fluid medium whose resistance varies directly with the speed it is observed that the frequency of damped vibration is 90 per minute and that the amplitude decreases to 20% of its initial value in one complete vibration. Find the frequency of the free undamped vibration of the system.
17. A mass of 50 kg is supported by an elastic structure of total stiffness 20 kN/m. The damping ratio of the system is 0.2. A simple harmonic disturbing force acts on the mass and at any time ‘t’ seconds the force is 60 sin 10t Newton. Find the amplitude of the vibrations and the phase angle caused by the damping.
(or)
18. An industrial machine weighing 445 kg is supported on a spring with a statical deflection of 0.5 cm. If the machine has rotating imbalance of 25 kg-cm, determine the force transmitted at 1200 rpm and the dynamic amplitude at that speed.
19. Three rotors A, B and C having moment of inertia of 2000, 6000 and 3500 kg-m2 respectively are carried on a uniform shaft of 0.35m diameter. The length of the shaft between the rotors A and B is 6 meter and between B and C is 32 meter. Find the natural frequency of the torsional vibrations, the modulus of rigidity for the shaft material is 80 GN/m2.
(or)
20. A steel bar 25 mm wide and 50 mm deep is freely supported at two points of a mete apart and carries a mass of 200 kg mid-way between them. Find the frequency of the natural transverse vibrations, neglecting the mass of the bar. Take E = 28 x 105 N/m2. What will the frequency of vibration, if any additional mass of 200 kg is distributed uniformly along the length of the shaft?
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