Dynamics of Machine (ME-503 (B)) - Important Questions

Determine coefficient of fluctuation of speed, mass, or radius of gyration of flywheel from turning moment diagram areas and scales.

Define/explain coefficient of fluctuation of energy, coefficient of fluctuation of speed, fluctuation of energy and fluctuation of speed for flywheels.

Explain the turning moment diagram for a four-stroke cycle IC / reciprocating engine and its uses.

Draw and explain the turning moment diagram in general and discuss mean torque and fluctuations.

Find maximum and minimum speeds of a flywheel given mass, radius of gyration, fluctuation of energy and mean speed.

Explain how a flywheel controls speed fluctuations in an engine.

Explain how energy fluctuation and coefficient of fluctuation of speed are determined from the turning moment diagram.

Explain the terms coefficient of fluctuation of energy and coefficient of fluctuation of speed.

Differentiate between / compare the functions of a flywheel and a governor.

What do you mean by dynamically equivalent system?

For a horizontal reciprocating engine with given crank and rod lengths, speed, crank angle, gas pressure difference, reciprocating mass and bore, determine inertia force, piston force, piston effort, side thrust, connecting-rod thrust and crank effort.

Numerically calculate the turning moment on the crankshaft of a single-cylinder engine from piston pressure and reciprocating mass.

Define and explain sensitiveness/sensitivity, stability, isochronism and hunting in connection with governors.

Porter governor with upper arm 200 mm and lower arm 250 mm pivoted on axis: determine range of speed for limiting upper-arm angles 30b0 and 40b0 with given ball weight, central load and friction.

Derive an expression for the height of a Watt governor and show height is inversely proportional to square of speed.

Discuss controlling force and stability of a centrifugal governor and derive the stability condition in terms of the slope $dF_C/dr$ of the $F_C$ vs $r$ curve and $F_C/r$, including stable, unstable and isochronous cases.

Proell governor with 300 mm arms, offset lower pivots and 100 mm ball extensions: determine equilibrium speeds at minimum radius 200 mm and maximum radius 250 mm.

Explain hunting in centrifugal governors, including its causes, effects and methods of prevention.

Explain the characteristics of centrifugal governors such as sensitivity, stability, isochronism and effort with neat sketches.

What is the function of a governor? Give classification of governors.

Derive the controlling force equation for a gravity controlled centrifugal governor.

Calculate minimum speed of Proell governor with equal 200 mm arms pivoted on axis and 60 mm extensions.

What is the difference between Porter governor and Proell governor?

What is the function of governor? How does it differ from flywheel?

Define/explain primary balancing, secondary balancing, hammer blow, swaying couple and variation in tractive force.

Describe balancing of rotating masses in the same plane using graphical and analytical methods.

Explain balancing of multi-cylinder in-line engines and the Lanchester balancing technique.

For a rotating shaft with masses in different planes spaced apart, find the unknown mass and relative angular settings for complete balance.

Calculate primary and secondary unbalanced forces for a three-cylinder radial engine with common crank.

Define balancing of rotating masses and explain the harmful effects of unbalanced rotating parts in high-speed engines.

Explain the direct and reverse crank method to determine unbalance forces in radial engines.

Numerically determine the magnitude and angular position of the balancing mass for multiple coplanar rotating masses on a shaft.

Derive the expression for tractive couple (variation in tractive force) for an uncoupled two-cylinder locomotive engine.

Determine balancing mass and residual unbalance force for a single-cylinder engine with partial balancing of reciprocating mass.

Derive the expressions for swaying couple and hammer blow for an uncoupled two-cylinder locomotive engine.

Explain what in-line engines are, how they are balanced, and whether complete balancing is possible.

Define clutch, its types and explain the working of a cone / conical clutch with neat sketch.

What is meant by the expression friction circle? Deduce an expression for the radius of friction circle in terms of radius of the journal and angle of friction.

Describe with neat sketch the working of a single plate friction clutch.

Numerical to determine power transmitted by a single plate clutch with both sides effective from outer/inner size, limiting pressure, friction coefficient and speed assuming uniform wear.

Define lubrication in bearing. What do you understand by boundary and fluid film lubrication?

Find the power lost in friction for a conical pivot bearing with given diameter, load, cone angle, speed and friction coefficient assuming uniform pressure and uniform wear.

Determine the maximum, minimum and average pressure in a plate clutch for given axial force and inner/outer radii assuming uniform wear.

Estimate power absorbed in friction and number of collars required for a multi-collar thrust bearing with given collar/shaft diameters, uniform pressure, friction coefficient, speed and axial load.

Derive the formula for maximum torque transmitted by a single plate clutch with uniform pressure intensity in terms of outer/inner radii, coefficient of friction and axial load.

Design numerical on single dry plate clutch to find mean radius, face width and outer/inner radii from power, speed, pressure limit and friction coefficient.

Design the outer and inner radii and find power absorbed in friction for a hollow conical pivot with given load, cone angle, limiting pressure, diameter ratio, speed and friction coefficient assuming uniform pressure.

What is a dynamometer, what are its types, and what is the difference between absorption and transmission dynamometers including torsion dynamometers?

Describe working of band and block brake with neat sketch

Numerical problem on power measurement using shaft twist in a torsion dynamometer.

Explain working of internal expanding brake with neat sketch

What do you understand by Cam? Explain its working principle with neat sketch.

Numerical problem on simple band brake to find braking torque from lever, drum, wrap angle, effort and friction

Describe single shoe brake with neat sketch and advantage of double shoe brake over single shoe brake

Short notes on absorption and transmission dynamometers and dynamic analysis of cams.

Numerical problem on double shoe brake to find spring force for given torque and shoe width for allowable bearing pressure

Describe with sketches a torsion dynamometer and explain the calculations for power transmitted.

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 $45\,N$.

A uniform disc of diameter $300\text{ mm}$ and of mass $5\text{ kg}$ is mounted on one end of an arm of length $600\text{ mm}$. The other end of the arm is free to rotate in a universal bearing. If the disc rotates about the arm with a speed of $300\text{ r.p.m.}$ clockwise, looking from the front, with what speed will it process about the vertical axis?

In a four bar chain ABCD, link AD is fixed and the crank AB rotates at $10$ radians per second clockwise. Lengths of the links are $AB = 60\ mm$; $BC = CD = 70\ mm$; $DA = 120\ mm$. When angle $DAB = 60^{\circ}$ and both B and C lie on the same side of AD, find

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 $BAD = 135^{\circ}$. If the velocity of B is $1.8\ m/s$ in the clockwise direction, find: