STRENGTH OF MATERIALS FOR MECHANICAL ENGINEERS

1. BIBIN CHIDAMBARANATHAN
STRENGTH
OF
MATERIALS
FOR MECHANICAL ENGINEERS

2. Engineering Mechanics
• It is the branch of science in which it deals with the laws and
principles of mechanics, and their application with engineering
problems.
• For an engineer, the knowledge of mechanics is very essential.
• It helps an engineer in planning, designing, and construction of
various types of structures and machines.
• If an engineer studies engineering mechanics in systematic and
scientific manner than he can take up his job more skillfully.

3. Types of Engineering Mechanics

4. Mechanics of fluids
• The mechanics of fluids is the branch of mechanics that deals
with liquids or gases.
• Fluids are commonly used in engineering applications. They can
be classified as incompressible, or compressible.
• While all real fluids are compressible to some degree, most
liquids can be analyzed as incompressible in many engineering
applications.
• Applications of fluid mechanics abound, from hydraulics and
general flow in pipes to air flow in ducts to advanced applications
in turbines and aerospace.

5. Ideal fluids
• An ideal fluid is a fluid that is incompressible and no internal resistance to
flow (zero viscosity).
• In addition ideal fluid particles undergo no rotation about their center of
mass (irrotational).
• An ideal fluid can flow in a circular pattern, but the individual fluid particles
are irrotational.
• Real fluids exhibit all of these properties to some degree, but we shall often
model fluids as ideal in order to approximate the behavior of real fluids.
• When we do so, one must be extremely cautious in applying results
associated with ideal fluids to non-ideal fluids.

6. Real fluids
• Fluid that have viscosity(μ > 0) and their motion known
as viscous flow.
• All the fluids in actual practice are real fluids.

7. Incompressible fluids
• The fluid whose density doesn't vary in any sort of flow
is considered as incompressible fluid.
• Incompressible flow does not imply that the fluid itself is
incompressible.

8. Solid Mechanics
• The solid mechanics may be defined as a branch of
applied mechanics that deals with behaviours of solid
bodies subjected to various types of loadings.
• This is usually subdivided into further two streams i.e
• Mechanics of rigid bodies and
• Mechanics of deformable solids.

9. Mechanics of rigid bodies
• A rigid body is a body which does not deform under the
influence of forces.
• In all real applications, there is always deformation,
however, many structures exhibit very small
deformations under normal loading conditions, and rigid
body mechanics can be used with sufficient accuracy in
those cases.

10. Statics
• It is the branch which deals with the forces and their
effects on an object or a body at rest.
• For example, if we have an object or a body at rest and
we deal with the forces and their effects that are acting
on the body than we are dealing with static branch of
engineering mechanics.

11. Dynamics
• It is the branch which deals with the forces and their
effects on the bodies which are in motion.
• For example, if we have a body that is moving and we are
dealing with the forces and their effects on the moving
body than we are dealing with dynamics branch.

12. Kinetics
• Kinetics is defined as the branch of dynamics which deals
with the bodies that are in motion due to the application
of forces.

13. Kinematics
• It is defined as the branch of dynamics which deals with
the bodies that are in motion, without knowing the
reference of forces responsible for the motion in the
body.

14. Mechanics of deformable bodies
• The mechanics of deformable bodies deals with how
forces are distributed inside bodies, and with the
deformations caused by these internal force
distributions.
• These internal force produce "stresses" in the body,
which could ultimately result in the failure of the
material itself.

15. Theory of Elasticity
• The theory of elasticity treats the relationship between
forces applied to an object and the resulting
deformations.
• In practice, the analysis of the elastic behaviour of a
material is reduced to the study of simple deformations
and the determination of the corresponding elastic
constants.

16. Theory of plasticity
• the branch of mechanics that investigates the
deformation of solids beyond the elastic limits.
• Not directly concerned with the physical explanation of
the properties of plasticity
• it studies the macroscopic properties of plastic solids
and deals with methods for the determination of the
distribution of stresses and deformations in solids that
undergo plastic deformation.

17. Strength of Materials
• The mechanics of deformable solids which is branch of
applied mechanics is known by several names i.e.
strength of materials, mechanics of materials etc.
• In materials science, the strength of a material is its
ability to withstand an applied load without failure.
• A load applied to a mechanical member will induce
internal forces within the member called stresses when
those forces are expressed on a unit basis.

18. SYLLABUS
UNIT I STRESS, STRAIN AND DEFORMATION OF SOLIDS
Rigid bodies and deformable solids – Tension, Compression
and Shear Stresses – Deformation of simple and compound
bars – Thermal stresses – Elastic constants – Volumetric
strains – Stresses on inclined planes – principal stresses
and principal planes – Mohr’s circle of stress.

19. SYLLABUS
UNIT II TRANSVERSE LOADING ON BEAMS AND STRESSES
IN BEAM
Beams – types transverse loading on beams – Shear force
and bending moment in beams – Cantilevers–Simply
supported beams and over hanging beams. Theory of simple
bending – bending stress distribution – Load carrying
capacity – Proportioning of sections – Flitched beams – Shear
stress distribution.

20. SYLLABUS
UNIT III TORSION
Torsion formulation stresses and deformation in circular and
hollows shafts – Stepped shafts – Deflection in shafts fixed at
the both ends – Stresses in helical springs – Deflection of
helical springs, carriage springs.

21. SYLLABUS
UNIT IV DEFLECTION OF BEAMS
Double Integration method – Macaulay’s method–Area
moment method for computation of slopes and deflections in
beams – Conjugate beam and strain energy – Maxwell’s
reciprocal theorems.

22. SYLLABUS
UNIT V THIN CYLINDERS, SPHERES AND THICK CYLINDERS
Stresses in thin cylindrical shell due to internal pressure
circumferential and longitudinal stresses and deformation in
thin and thick cylinders – spherical shells subjected to
internal pressure –Deformation in spherical shells – Lame’s
theorem.

23. SYLLABUS
TEXT BOOKS
T1. Bansal, R.K., "Strength of Materials", Laxmi Publications (P) Ltd., 2007
T2. Jindal U.C., "Strength of Materials", Asian Books Pvt. Ltd., New Delhi, 2007

24. SYLLABUS
REFERENCES
R1. Egor. P.Popov “Engineering Mechanics of Solids” Prentice Hall of India, New
Delhi, 2001
R2. Subramanian R., "Strength of Materials", Oxford University Press, Oxford
Higher Education Series, 2007.
R3. Hibbeler, R.C., "Mechanics of Materials", Pearson Education, Low Price
Edition, 2007
R4. Ferdinand P. Been, Russell Johnson, J.r. and John J. Dewole "Mechanics of
Materials", Tata
McGraw Hill Publishing ‘co. Ltd., New Delhi, 2005.

25. Thank You