JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
II Year B.Tech. P.E.. I - Sem L T/P/D C
4 -/-/- 4
ELEMENTS OF MECHANICAL ENGINEERING

Objective: To give an insight to students about the behaviour of materials under external forces. The concept of stress, strain, elasticity etc. as applied to various structures under loading are included.

UNIT - I:

Stresses and strains: kinds of – stress-strains, elasticity and plasticity, Hooks law, stress –strain diagrams, modules of elasticity, Poisson’s ratio, linear and volumetric strain, relation between E, N, and K, bars of uniform strength, compound bars and temperature stresses.

UNIT - II:

Types of supports – loads – Shear force and bending moment for cantilever and simply supported beams without overhanging for all types of loads. Theory of simple bending, simple bending formula, Distribution of Flexural and Shear stress in Beam section – Shear stress formula – Shear stress distribution for some standard sections.

UNIT - III:

Thin cylindrical shells: stress in cylindrical shells due to internal pressures, circumferential stress, longitudinal stress, design of thin cylindrical shells, spherical shells, change in dimension of the shell due to internal pressure, change in volume of the shell due to internal pressure
Thick Cylinders: Lame’s equation- cylinders subjected to inside and outside pressures Columns and Struts.

UNIT - IV:

Internal combustion engines: classification of IC engines, basic engine components and nomenclature, working principle of engines, Four strokes and two stroke petrol and diesel engines, comparison of CI and SI engines, comparison of four stroke and two stroke engines, simple problems such as indicated power, brake power, friction power, specific fuel consumption, brake thermal efficiency, indicated thermal efficiency and mechanical efficiency.

UNIT - V:

Belts - Ropes and chain: belt and rope drives, velocity ratio, slip, length of belt , open belt and cross belt drives, ratio of friction tensions, centrifugal tension in a belt, power transmitted by belts and ropes, initial tensions in the belt, simple problems.
Gear trains: classification of gears, gear trains velocity ratio, simple, compound –reverted and epicyclic gear trains.

Text Books:

1. ”Strength of Materials and Mechanics of Structures”, B.C.Punmia, Standard Publications and distributions, 9 th ed. (units I - III)
2. Thermal Engineering, Ballaney,P.L., Khanna Publishers, 2003 (Units IV.
3. Theory of Machines , S.S. Rattan , Tata McGraw Hill (Units V).

Outcome: The student would be exposed to basic mechanical engineering machinery.