Important RGPV Question
ME-503 (B) Dynamics of Machine
V Sem, ME
UNIT 1-Dynamics of Engine Mechanisms
Q.1) In a pin jointed four bar mechanism ABCD, the lengths of various links are as follows: AB = 25 mm; BC-87.5 mm; CD = 50 mm and AD = 80 mm. The link AD is fixed and the angle BAD=135°. If the velocity of B is 1.8 m/s in the clockwise direction, find:
i) Velocity and acceleration of the mid point of BC
ii) Angular velocity and angular acceleration of link CB and CD.
(RGPV Nov 2023)
Q.2) In a turning moment diagram, the areas above and below the mean torque line taken in order are 4400, 1150, 1300 and 4550 mm² respectively. The scales of the turning moment diagram are: Turning moment, 1 mm = 100 N-m; Crank angle, 1 mm 1º Find the mass of the flywheel required to keep the speed between 297 and 303 r.p.m., if the radius of gyration is 0.525 m.
(RGPV Nov 2023)
Q.3) Explain the terms ‘fluctuation of energy’ and ‘fluctuation of speed’ as applied to flywheels.
(RGPV Nov 2023)
Q.4) A Porter governor has links 150 mm long and are attached to pivots at a radial distance of 30 mm from the vertical axis of the governor. The mass of each ball is 1.75 kg and the mass of the sleeve is 25 kg. The governor sleeve begins to rise at 300 r.p.m. when the links are at 30° to the vertical. Assuming the friction force to be constant, find the minimum and maximum speed of rotation when the inclination of the links is 45° to the vertical.
(RGPV Nov 2023)
Q.5) What is the function of a flywheel? How does it differ from that of a governor?
(RGPV Nov 2023)
Q.6) What do you mean by dynamically equivalent system?
(RGPV Nov 2022)
Q.7) A single cylinder two stroke vertical engine a bore of 30 cm and a stroke of 40 cm with a connecting rod of 80 cm long. The mass of the reciprocating parts is 120 kg. When the piston is at quarter stroke and moving down, the pressure on it is 70 N/cm². If the speed of the engine crank shaft is 250 rpm clockwise find the turning moment on the crank shaft, Neglect the mass and inertia effects on connecting rods and crank.
(RGPV Nov 2022)
Q.8) Explain the terms coefficient of fluctuation of energy and coefficient of fluctuation of speed.
(RGPV June 2020)
Q.9) Derive an equation for fluctuation of energy in case of flywheel.
(RGPV June 2020)
Q.10) The lengths of crank and connecting rod of a horizontal reciprocating engine are 210 mm and 1.0 m respectively. The crank is rotating at 420 r.p.m. When the crank has turned 30° from the inner dead centre, the difference of pressure between the cover end and piston end is 0.4 N/ mm². If the mass of the reciprocating parts is 100 kg and cylinder bore is 0.4 m, then calculate:
i) Inertia force
ii) Force on piston
iii) Piston effort
iv) Thrust on the sides of cylinder walls
v) Thrust in the connecting rod
vi) Crank-effort and Neglect the effect of piston rod diameter and frictional resistance.
(RGPV Nov 2022)
UNIT 2-Governor Mechanisms
Q.1) Define and explain the following terms relating to governors:
i) Stability
ii) Sensitiveness
iii) Isochronism
iv) Hunting
(RGPV Nov 2022)
Q.2) Prove that the sensitiveness of a Proell governor is greater than that of a Porter governor.
(RGPV Nov 2022)
Q.3) Write short note on ‘coefficient of insensitiveness’ of governors.
(RGPV Nov 2022)
Q.4) A Proell governor has arms of 300 mm length. The upper arms are hinged on the axis of rotation, whereas the lower arms are pivoted at a distance of 35 mm from the axis of rotation. The extension of lower arms to which the balls are attached are 100 mm long. The mass of each ball is 8 kg and the mass on the sleeve is 60 kg. At the minimum radius of rotation of 200 mm, the extensions are parallel to the governor axis. Determine the equilibrium speed of the governor for the given configuration. What will be the equilibrium speed for the maximum radius of 250 mm?
(RGPV Nov 2022)
Q.5) Give complete classification of governors. How centrifugal
governors differ from inertia governors.
(RGPV June 2020)
Q.6) Explain Hunting of centrifugal governors. Discuss gravity and spring controlled centrifugal governors.
(RGPV June 2020)
UNIT 3- Balancing of Inertia Forces and Moments in Machines
Q.1) A single cylinder engine runs at 250 r.p.m. and has a stroke of 180 mm. The reciprocating parts has a mass of 120 kg and the revolving parts are equivalent to a mass of 70 kg at a radius of 90 mm. A mass is placed opposite to the crank at a radius of 150 mm to balance the whole of the revolving mass and two- thirds of the reciprocating mass. Determine the magnitude of the balancing mass and the resultant residual unbalance force when the crank has turned 30° from the inner dead centre, neglect the obliquity of the connecting rod.
(RGPV Nov 2023)
Q.2) What are in-line engines? How are they balanced? It is possible to balance them completely.
(RGPV Nov 2023)
Q.3) Explain why only a part of the unbalanced force due to reciprocating masses is balanced by revolving mass.
(RGPV Nov 2022)
Q.4) In figure 1 and figure 2 A, B, C and D are four masses carried by a rotating shaft at radii of 10, 12.5, 20 and 15 cm respectively, The planes in which the masses revolve are spaced
60 cm apart and the weights of B, C and D are 10, 5, and 4 kg respectively. Find the required mass A and the relative angular settings of the four masses so that the shaft shall be in complete balance. (RGPV June 2020)
Q.5) Derive the following expressions, for an uncoupled two cylinder locomotive engine:
i) Swaying couple
ii) Hammer blow
(RGPV Nov 2023)
Q.6) The following data refer to two-cylinder locomotive with crank 90°. Reciprocating mass per cylinder 300 kg, Crank radius = 0.3 m, Driving wheel dia. = 1.8 m Dist. between cylinder centre lines 0.65 m Dist. between the driving wheel = 1.55 m. Determine:
i) The fraction of the reciprocating masses to be balanced, if the hammer blow is not to exceed 46 × 103 N at 96.5 km/hr.
ii) The variation in tractive effort.
iii) The maximum swaying couple.
(RGPV Nov 2022)
UNIT 4- Friction
Q.1) A conical pivot supports a load of 20 kN, the cone angle is 120º and the intensity of normal pressure is not to exceed 0.3 N/mm². The external diameter is twice the internal diameter. Find the outer and inner radii of the bearing surface. If the shaft rotates at 200 r.p.m. and the coefficient of friction is 0.1, find the power absorbed in friction. Assume uniform pressure.
(RGPV Nov 2023)
Q.2) Determine the maximum, minimum and average pressure in plate clutch when the axial force is 4 kN. The inside radius of the contact surface is 50 mm and the outside radius is 100 mm. Assume uniform wear.
(RGPV Nov 2023)
Q.3) Determine the maximum, minimum and average pressure in plate clutch when the axial force is 4 kN. The inside radius of the contact surface is 50 mm and the outside radius is 100 mm. Assume uniform wear.
(RGPV Nov 2022)
Q.4) Derive an expression for the friction moment of a conical
pivot assuming
a) Uniform Pressure
b) Uniform wear
(RGPV June 2020)
UNIT 5-Brakes
Q.1) The layout and dimensions of a double shoe brake is shown in Fig. 1. The diameter of the brake drum is 300 mm and the contact angle for each shoe is 90°. If the coefficient of friction for the brake lining and the drum is 0.4, find the spring force necessary to transmit a torque of 30 N-m. Also determine the width of the brake shoes, if the bearing pressure on the lining material is not to exceed 0.28 N/mm². (RGPV Nov 2023)
Q.2) With the help of neat sketches Explain following brakes:
a) Band Brakes
b) Block Brakes
c) Internal expanding brakes
d) External shoe brakes
(RGPV June 2020)
Q.3) What is the difference between absorption and transmission dynamometers? What are torsion dynamometers?
(RGPV Nov 2023)
Q.4) Describe with sketches one form of torsion dynamometer and explain with detail the calculations involved in finding the power transmitted.
(RGPV Nov 2022)
Q.5) A cam consists of a circular disc of diameter 75 mm with its centre displaced 25 mm from the camshaft axis. The follower has a flat surface (horizontal) in contact with the cam and the line of action of the follower is vertical and passes through the shaft axis as shown in Figure 1. The mass of the follower is. 2.3 kg and is pressed downwards by a spring which has a stiffness of 3.5 N/mm. In the lowest position the spring force is 45 N.
i) Derive an expression for the acceleration of the follower in terms of the angle of rotation from the beginning of the lift.
ii) As the cam shaft speed is gradually increased, a value is reached at which the follower begins to lift from the cam surface. Determine the camshaft speed for this condition.
(RGPV Nov 2022)
Q.6) Write short notes on followings
a) Different types of dynamometers and their applications
b) Single plate and multi plate clutches
c) Lanchester technique of engine balancing
d) Dynamic analysis of cams
(RGPV June 2020)
— Best of Luck for Exam —
