1-Introduction-of-Engg-mechanics.ppt.pdf

Engineering mechanics

1. Engineering Mechanics
(BMEC-002)
Er. Ravish Arora
Assistant Professor,
Department of Mechanical Engineering,
MMEC, MMDU-Mullana
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2. •It is a subject which describes and predicts the effects of forces on
rigid bodies.
•Deals with the study of bodies at rest or in motion when subjected to
external forces.
Statics
deals with forces and their
effects while acting upon the
bodies at rest.
Dynamics
mainly concerned with the forces
and their effects, while acting
upon the bodies in motion
KINEMATICS
deals with bodies in motion, without any
reference to the forces. (Considers
only the motion and not its cause)
KINETICS
deals with bodies in motion, due to
application of force (Considers both
motion and its cause)
Engineering Mechanics
2
Engineering Mechanics

3. UnitPart Topics
Unit 1
(Forces
Systems)
A
Basic concepts ,system of forces,
component of forces, resultant of
forces Moment of a force; reduction of
a force system to a force and a couple,
equivalent systems, forces in
equilibrium, principle and laws of
equilibrium.
B
Free body diagrams, Lami’s Theorem,
equations of equilibrium, problems in
two dimensions, plane frames and
trusses, method of sections and joints.
Content of the course
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4. 4
UnitPart Topics
Unit 2
(Concept
of C.G,
MOI and
virtual
work)
A
Concept of center of gravity and
centroid, Centroid of simple figures
from first principle, centroid of
composite sections; theorem of parallel
and perpendicular axes.
B
Moment of inertia of simple
geometrical figures, polar moment of
inertia. Virtual work: Principles of
virtual work, applications to practical
problems.

5. Unit 3
(Friction
and
lifting
machine
)

A
Laws of Coulomb friction, angle of
contact, angle of repose, problems
involving large and small contact
surfaces, Analysis of body on rough
inclined plane, ladder friction, wedge
friction
B
Lifting Machines: Definition, reversible
and irreversible machines, laws of
machines, mechanical advantage,
efficiency, friction of machines in terms
of load and effort, important lifting
machines like wheel, axle, worm and
worm wheel ,pulleys, differential pulleys
and screw jack, crab winches.
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6. 6
Unit 4
(Dynami
cs)

A
Belt drives: Belt drive, velocity ratio,
compound belt drive, length of belt,
transmission of power, centrifugal tension.
Toothed Gearing: Definition, Analysis of
simple, compound, reverted and epicyclic
gear trains.
B
Mechanical Vibrations covering Basic
terminology, free and forced vibrations,
resonance and its effects; Degree of freedom;
Derivation for frequency and amplitude of
free vibrations without damping and single
degree of freedom system, simple problems,
types of pendulum, use of simple, compound
and torsion pendulums

7. FUNDAMENTAL UNITS
•The measurement of physical quantities is one of the most
important operations in engineering.
•Every quantity is measured in terms of some arbitrary, but
internationally accepted units, called fundamental units.
S. I. Units
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DERIVED UNITS
•Sometimes, the units are also expressed in other units (which are
derived from fundamental units) known as derived units
e.g. units of area, velocity, acceleration, etc.
•All the physical quantities, met with in Engineering
Mechanics, are expressed in terms of three fundamental
quantities, i.e.
1.length, 2. mass and 3. time.
INTERNATIONAL SYSTEM OF MEASUREMENTS
Système International

8. The following derived units will be used in present
course:
1.Density (Mass density) kg / m
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2.Force N (Newton)
3.Pressure N/mm
2
or N/m
2

4.Work done (in joules) J = N-m
5.Power W = J/s
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