** BARC SCIENTIFIC ASSISTANT (SA) **

**DETAILED SYLLABUS MECHANICAL ENGINEERING **

**Preface: This Detailed Syllabus is prepared after extensive research and analysis of all previous year Paper of BARC SA Mechanical. **

**APPLIED MECHANICS**

**➢**** Force & Equilibrium– Force definition, Units, Classification, Force System (Coplanar, Non-Coplanar, Concurrent, Non-concurrent, collinear etc.) Transmissibility of force, Resultant of force, Component of force, Law of forces- Parallelogram, Triangle & Polygon Law of forces, Principle of Equilibrium, Lami’s theorem. **

**➢**** Moment & Couple- Definition & Units of moment, Type of moment, Varignon’s principle of moment, Definition and units of Couple, Classification, Daily life examples, Engineering applications of**** moments- (Simple lever)**

**➢**** Friction & its Application- Basic definition, Types of Friction- Static & Kinetic, Limiting, Sliding, Rolling etc. Angle of friction, Angle of repose, Equilibrium of body on horizontal & inclined plane. Application of friction- L****adder friction, Screw jack etc.**

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**➢**** Centre of Gravity & Moment of Inertia– Centroid of plane figures, centre of gravity of solid body, Definition and units of Moment of Inertia, Moment of inertia of Simple areas, Parallel axis theorem, Perpendicular axis th****eorem, Section modulus.**

**➢**** Rectilinear Motion (Kinematics) – Basic terms, Types of velocity & acceleration, motion under uniform acceleration, motion under force of gravity, Graphical representation of velocity & displacement wrt time, motion under variable**** acceleration. **

**➢**** Angular Motion (Rotation) – Basics term- Angular displacement, velocity & acceleration, motion of rotation under constant angular acceleration, analogy of linear & angular motion, Tangential velocity & acceleration of rotating body.**

**➢**** Kine****tic Motion– Torque, work done by torque, angular momentum, mass moment of inertia- uniform rod, circular ring, circular lamina, solid sphere, thin spherical shell, solid cylinder, solid disc etc. Radius of gyration, Kinetic energy of Rotation, Relation between torque and angular acceleration.**

2. **STRENGTH OF MATERIAL**** **

➢ Simple Stress & Strain- Basics of stress, Classification of Stress, Strain and its types, True stress & strain, Hooke’s law, Elastic Constants and its relation, volumetric strain under triaxial loading, Hydrostatic state of stress, Bar under uniaxial loading, Elongation- prismatic bar, tapered bar, composite bodies, due to self weight, thermal Stress & strain.

➢ Strain energy- Resilience, Proof resilience, modulus of resilience, toughness & modulus of toughness, strain energy in shear & torsion, bending etc.

➢ Shear Force & Bending moment Diagram- Beam and its type, Types of support, Types of load, Reaction calculation, Notation & Sign Convention, Relation between Shear force & bending moment, Types of SFD & BMD Curve. ➢ Deflection of Beam- Slope and deflection in Cantilever & Simply support beam.

➢ Bending & Shear Stress in Beam- Pure bending, Bending Equation and its analysis, bending stress distribution, beam of uniform strength, comparison of different shapes of beam, Shear stress in beam, shear stress distribution.

➢ Torsion in Shaft- Definition, basic terms, torsion equation, polar moment of inertia, polar Section modulus, Torsional stiffness, power transmission, Comparison of solid and hollow shaft, shaft in Series and parallel, combined bending and torsion.

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➢ Pressure Vessel- Definition, types of pressure vessels Longitudinal and hoop stress in thin cylindrical and spherical vessels, Different types of strain in thin cylindrical and spherical vessels. Comparison between thin and thick pressure vessels.

➢ Principle Stress & Mohr Circle- State of stress, uniaxial stress on oblique plane, complementary stress, complex stress- 2D Stress system, Biaxial stress, Principle stress and plane, Mohr circle.

➢ Theory of column- Strut & column, Slenderness ratio, Euler’s buckling load, Equivalent length, Rankine crippling load, rankine constant.

➢ Theory of failure- Need of failure theory, maximum principle stress theory, maximum shear stress theory, maximum principle strain theory, total strain energy theory & maximum distortion energy theory.

**3. THEORY OF MACHINE & VIBRATION **

➢ Simple Mechanism- Kinematic link and types, Kinematic pair, classification, types of constrained motion, types of joint, Kinematic chain, Degree of freedom, kutzbach criterion, Grashof laws, Inversion of mechanisms- Four bar chain, single slider & double crank mechanism, slider, special mechanism (toggle, steering, intermittent motion, straight line)

➢ Gear & Gear train- Classification, Gear terminology, Forms of gear tooth- involute & cycloidal, comparison, length of contact & arc contact, velocity & gear ratio, interference in involute gear & its prevention. Gear train- Simple, compound, reverted & epicyclic

➢ Belt drive- Selection, types of belt Drive, types of belt- circular, v-belt & circular or rope. Flat belt- Velocity ratio, creep of belt, Length of open & cross belt drive, power transmission, ratio of driving tension, centrifugal tension, conditions for maximum power transmission, initial tension, V-belt drive- advantage & disadvantage, ratio of driving tension. Rope drive- types, material & Application

➢ Governor- working principle, classification- inertia & centrifugal, height of watt & porter governor, hunting, sensitiveness, isochronous governor, controlling force, effort & power of governor.

➢ Flywheel- Definition, turning moment, kinetic energy, maximum fluctuation of energy, coefficient of fluctuation of speed, coefficient of fluctuation of energy.

➢ Cam & Follower- Definition, classification of cam, classification of Follower, cam Nomenclature.

➢ Vibration- Types of vibratory motion- Natural, damped & forced vibration, types of free vibration, Solution method of longitudinal vibration- equilibrium, energy, Rayleigh method etc. Transverse Vibration, Torsional vibration, cutting of spring, damped vibration, forced Vibration.

**4. MACHINE DESIGN **

➢ Power Screw- terminology of screw thread, Types of thread- unified standard, square, acme, knuckle, buttress, metric etc. Types of screw fastening, designation of screw thread.

➢ Theory of Spring- types of spring, Series and parallel Combination, material, term used in helical spring. Closed coil helical compression spring- strain energy, deflection, stiffness, shear stress.

➢ Shaft’s Keys & Coupling- uses of key, material, classification, application, shear and crushing design of keys. Types of shaft Coupling- Rigid & Flexible Coupling.

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➢ Bearing- Definition, Classification, sleeve bearing- Thrust (Pivot & collar) & Journal, thin, thick & zero film lubrication bearing, solid & split bush bearing, slipper bearing, Roller contact bearing- ball & roller, life of ball and roller bearing.

➢ Riveted & Welded Joint- Difference between permanent & temporary fastening, Rivet and its different types of shapes, types of Riveted joint, types failure in rivet joint, strength and efficiency. Types of welded joint, strength of transverse fillet joint, parallel fillet joint, butt weld joint.

➢ Design against Fluctuating load- Fatigue & endurance limit, completely reversed stress, repeated & fluctuating stress, factor of safety, stress concentration- static & fatigue stress concentration factor, notch sensitivity.

**5. FLUID MECHANICS & HYDRAULIC MACHINES **

➢ Fluid Properties- Basics about fluid, mass density, weight density, Specific volume, Specific gravity, viscosity Concepts & units, Kinematic viscosity, effect of temperature & pressure on viscosity, classification of fluid- Newtonian & Non-Newtonian, ideal & real fluid, bulk modulus, Compressibility, Surface tension pressure inside jet, bubble, droplet etc. wetting and non-wetting surface, capillary rise & depression.

➢ Pressure & Measurement- Fluid pressure, various units, gauge, absolute, vacuum & atmospheric pressure, Pascal’s law, Hydrostatic law, Measurement: Manometer- piezometer, U-tube, single column, differential & Mechanical Gauge.

Hydrostatic forces- centre of pressure, total pressure. Vertical plane, horizontal plane, inclined plane, curved surface submerged in liquid.

➢ Buoyancy & Flotation- Buoyant force, centre of buoyancy, Archimedes principle, metacentre & metacentre height, Condition of equilibrium of floating and submerged bodies, time period of oscillation.

➢ Fluid Kinematics- Classification of Fluid flow- Steady & unsteady, uniform & Non-Uniform, Compressible & Incompressible, Laminar & Turbulent, Rotational & Irrotational, One Dimension, Two dimension and three-dimension flow. Stream lines, streak line & path line. Continuity Equation, acceleration of fluid- convective & local/temporal acceleration, rotational component, vorticity, circulation, velocity potential and streamline function.

➢ Fluid Dynamics & Flow Measurement- Different kind of force acting on fluid particle, Reynolds equation, naiver stokes equation, Euler’s equation, Bernoulli equation and its assumptions, Application of Bernoulli equation- Discharge measurement & velocity measurement. Venturimeter, orifice meter, flow nozzle, pitot tube, anemometer, variable area flow meter, positive displacement flowmeter, current meter, rotameter, flow through orifice, hydraulic coefficients.

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➢ Viscous Flow- Reynolds number, nature of flow for pipe & open Channel, entrance length, laminar flow through circular pipe, laminar flow between two fixed parallel plate, shear stress distribution, velocity distribution, discharge through pipe, mean velocity, pressure drop in pipe.

➢ Flow through pipes- loss of energy in pipe, major energy loss- Darcy weisbach & chezy Formula, Minor energy losses, Hydraulic grade line, total energy line, siphon, power transmission in pipe, water hammer.

➢ Dimensionless Numbers- Reynolds Number, Euler’s Number, Weber Number, Froude Number, Mach Number.

➢ Impact of Jets- force exerted by jet on Stationary & moving vertical, inclined & curved plate.

➢ Hydraulic Turbine- layout of hydro electric power plant, power and efficiency, classification of turbine, impulse turbine, Pelton wheel- components, design parameters, reaction turbine- Francis, Kaplan & propeller, draft tube, Specific speed, unit quantities, characteristics curve.

➢ Hydraulic pump- classification of pump, centrifugal pump- components & working Principle, Different types of head, power & efficiency. Specific speed of pump, pump in series and parallel, priming of pump, cavitation, net positive suction head, characteristic curve of centrifugal pump. Reciprocating pump- components, discharge, air vessel.

➢ Fluid System- Hydraulic press, accumulator, intensifier, Ram, Airlift pump.

**6. Basic Thermodynamics **

➢ Basics Concepts- Definition of Thermodynamic, System & surrounding, types of system, thermodynamic properties & its types, thermodynamic equilibrium, state of the system, types of process, cyclic process, path & point function, Property of pure substance, Gibbs’s phase rule, zeroth law of thermodynamic, thermometry, temperature scale, Ideal gas equation, characteristics gas constant, universal gas constant, Various gas laws, homogeneous and heterogeneous systems, NTP & STP, Kinetic theory of gas.

➢ Energy & Energy Interactions- Energy- microscopic & macroscopic, energy interactions, Work- sign convention, types of work, expression for closed system work for- constant volume, constant pressure, isothermal, adiabatic & polytropic. Representation of all process on PV Diagram. Heat – sign Convention, specific heats & its values, adiabatic index, types of heat- sensible & latent heat.

➢ First law of Thermodynamics- statement, total energy, internal energy, energy of the isolated system, PMM-1, enthalpy & specific enthalpy, expression for heat for- constant volume, constant pressure, isothermal, adiabatic & polytropic. Free Expansion.

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➢ Second law of Thermodynamics- statement, thermal energy reservoir, heat engine, kelvin plank statement, PMM-2, clausius statement, COP of heat pump & refrigerator. Externally & internally reversible process, irreversible process.

➢ Entropy- Definition, Clausius inequality, Entropy change of the universe & system, T-dS relation, entropy change for finite body & phase change, entropy change for ideal gas, representation of various process on T-S curve, Carnot cycle- efficiency and drawback, Availability, irreversibility, Second law efficiency. Gibbs’s and Helmholtz function.

➢ Properties of pure Substance- phase change of pure substance, Property Diagram- P-T, P-v, T-s, h-s or mollier diagram. Quality and saturated liquid vapour mixture, enthalpy and entropy of pure substance.

**7. IC ENGINE **

➢ Basics & Air standard cycles- components of IC engine and its material, Nomenclature, two stroke and four stroke engine, otto, diesel and dual cycle, Comparison, mean effective pressure, performance parameter of ic engine, engine testing, Supercharging.

➢ Combustion, fuel & Emissions- Combustion reactions, stoichiometric combustion, equivalence ratio, combustion in SI & CI engine, abnormal combustion or knocking, factor affecting knocking/detonation in SI & CI engine, quality of fuel- octane & cetane number. Emission- pollutant from petrol and diesel engine, catalytic converter.

**8. Refrigeration & Air Conditioning **

➢ Refrigeration Cycle, Refrigerant & Equipment- VCRS- refrigeration effect, Compressor work, COP, wet & dry compression, effect of variation of properties on the performance, cascade system, Vapour absorption refrigeration System, Electrolux refrigeration, air refrigeration system- reversed brayton cycle, COP, isentropic efficiency, open & closed cycle. Refrigerant- designation, types, properties, ozone depletion, leakage detection, Compressor for different refrigerant, applications of refrigerant. Equipment- throttling device and types, Compressor and types. ➢ Air Conditioning (Psychrometry) – analysis of moist air- specific humidity, relative humidity, dry bulb, wet bulb & dew point temperature, psychrometer, psychometric chart, basic psychometric processes, sensible heat factor, by pass factor, air washer.

9.** POWER PLANT**

➢ Steam Power plant- Boiler classifications, boiler mountings & accessories, coal types and Analysis, rankine cycle and efficiency, method of improving performance of Rankine cycle, steam turbine- impulse & reaction, compounding, degree of reaction.

➢ Air Compressors- function, classification, reciprocating compressor- applications, Net work with and without clearance, multistage compressor,

➢ Nozzle- function and types, nozzle vs diffuser, Mach number in compressible flow, super saturated flow. ➢ Gas Turbine- Introduction, open and closed cycle, ideal and actual cycle, optimum pressure ratio. Reheating, regeneration, intercooling in gas turbine.

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**10. HEAT TRANSFER **

➢ Basics modes of heat transfer- Conduction- Fourier’s law, convection- newton law of cooling, radiation- Stefan Boltzmann law, thermal conductivity & diffusivity, insulator.

➢ Conduction- heat transfer through slab, composite slab, Conduction resistance- plane wall, cylinder & sphere. Convection resistance, critical radius of insulation.

➢ Convection- Forced convection- Nusselt number, Prandtl number. Free convection- Grashof number, Rayleigh number.

➢ Radiation- Definition, total hemispherical emissive power, total emissivity, black body, monochromatic emissive power & emissivity, grey body, absorptivity, reflectivity, transmissivity, Laws of radiation- Kirchhoff, plank, Wein’s displacement, Lambert cosine & Stefan Boltzmann.

**11. MATERIAL SCIENCE **

➢ Crystal Structure- Crystalline & amorphous material, Crystal system and bravice lattice- Simple Cubic, BCC, FCC, HCP. No of average atoms, coordination number, atomic packing factor. Crystal defects and types.

➢ Material Properties & Mechanical Test- various types of mechanical properties, tensile test, Brinell hardness test, Vickers hardness test, Rockwell’s hardness test, Moh’s hardness test, impact test- Izod & Charpy.

➢ Iron-Carbon Diagram & Heat Treatment- Cooling curve of pure iron, iron carbon diagram, peritectic, eutectic & eutectoid reaction, possible transformation of steel, classification of heat treatment, annealing and types, normalising, hardening, tempering, surface hardening and different types.

➢ Ferrous and Non-Ferrous- Classification of Metal, Ferrous- Iron ores, pig iron, wrought iron, cast iron and types, Steel- plain carbon steel & alloy steel, effects of alloying elements, stainless steel, tool steel, HSS etc. Non-Ferrous- Different types of non-ferrous alloys- copper, aluminum, magnesium, lead, nickel, tin, zinc, cobalt etc. Thermosetting & thermoplastic polymer.

**12. Production Technology & Manufacturing Processes**

➢ Welding- classification of welding process, Arc welding- AC & DC arc welding, TIG, MIG, Submerged arc welding, Chemical- Gas and thermite welding, Resistance welding and types, solid state welding and its types, heterogeneous welding- soldering and brazing. Weld ability and welding defects.

➢ Casting- terms associated with casting, types allowances & pattern, properties of moulding sand and types of sand, gating system, solidification time, riser, classification of casting process- temporary: – sand moulding, steel, full moulding, CO2 moulding, investment casting. Permanent- centrifugal casting, gravity & pressure die casting, shell moulding. Continuous casting.

➢ Metrology & Measurement: – Limits- lower and upper, tolerance, allowance, unilateral and bilateral limits, Fits- clearance, transition and interference. Hole and shaft basis system, Tolerance zone and grades, fundamental deviation, types of limit gauge, linear and angular measurement, measuring straightness, flatness, roundness and profile. Surface finish, lay and flaw.

➢ Forming- Terminology in metal forming, cold and hot working, Rolling and its types, operation in forging, type of forging, defects, extrusion and types, drawing, wire drawing, punching and blankng, powder metallurgy.

➢ Machining & Finishing- types of machining- orthogonal and oblique, Single point cutting tool terminology, tool signature, types of chips formation, mechanism of tool wear and types, Taylor’s tool life equation, shaping, planning, grinding, finishing operation, drilling and drill geometry, boring, reaming, trepanning, milling, jigs and fixture, lathe and lathe operation.

➢ Unconventional Machining- Classification- thermal energy method, electrochemical energy method, chemical energy method, mechanical energy method.

➢ CAD/CAM/CIM (LPSC centre)

**13. Industrial Engineering & Management **

➢ Work Study- method study – recording technique, Symbols, types of chart- operation, flow, multiple activity, SIMO, travel. Diagrams- flow and string. Work measurement- stop watch time study, PMTS, Work sampling.

➢ Quality Control- Quality of design and performance, Quality cost, total quality management, statistical quality control, process control chart, control chart types, operating characteristic curve.

➢ PERT/CPM- basic concept of network, dummy activity, critical path method- earliest and latest time, float, critical activities and path, PERT- optimistic, pessimistic and most likely time, expected time formula. Difference between CPM & PERT.

➢ Production, planning and Control- Routing, loading, balancing, scheduling, dispatch, Follower. Types of Production, Gantt chart, inventory control, Plant layout.

**14. Engineering Drawing **

➢ Various drawing instruments drawing Symbols, conic section and basic about projection, first angle and third angle projection.

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