The Mechanicals

Hydraulic & Fluid Mechanics Density/Mass density : mass/unit volume at standard temp and pressure. rho =M/V unit: kg /me Weight density/specific weight : weight /unit volume  at standard temperature and pressure. w=rho x g unit : N/me Specific volume : volume/unit mass of liquid  v=V/m unit : m3/ kg Specific gravity : it is defined as specific weight of liquid to specific weight of pure water at 4 degree C it has no unit Viscosity : it offers resistance to movement of one layer of liquid to another layer  Compressibility : properly change in volume to change in pressure. it is reciprocal of bulk modulus of elasticity. Surface tension : property of liquid which enables to resist tensile stress denoted by sigmaunit  : N/m Capalary : phenomena of rise /fall of surface in small tube held in liquid relatives. Pressure of liquid : When liquid contained in vessel it exerts at all points on side & bottom of vessel force per unit volume area calle

Important point of Strength of material Stress : P/A =N/mm2 Strain : Change in length / original length = No unit Hook's law = good for elastic limit Modulus of elasticity = linear stress/linear strain Poison ratio :  lateral strain / linear strain (Max. = 0.5) E = 210 kN/mm2 Strain roseter = used to measure liner strain. Max. stress at smaller end in tapper bar bolt pass through pipe both are tightly fitted with nut and washer so bolt in tension tube in compression bar cooled at -5 degree c it develop tensile stress. Energy stored in body = strain energy Total strain energy stored in body = Resilience Max. strain energy stored in body = Proof resilience Proof resilience / Unit volume = Modulus of resilience  Strain energy suddenly loaded = 4 x Gradually loaded  Contraflex point = bending moment change sign (overhanging beam)(simply supported beam) Shear force = 0, Bending moment = max Bending moment at fix end = max In pure bending = bending is constant, s

Strength of Material Mechanical Properties Hardness ;Resist the penetration (impact  load) Strength : Ability of material withstand of material without failure. Elasticity : It regain the original shape after removing load Plasticity : Permanent deformation after removing load. Mali ability : Converts to thin sheet without rupture Ductility : Draw in to thin wire. Brittleness : No deformation takes place & rupture (lake of ductility ) (cast iron) Toughness : absorb energy & plastic deformation without rupture. Fatigue: by repeatedly applied load program me and localized structure damage that occur. Creep : tendency of solid material to move slowly deform permanently under mechanical stress. Stress : Load applied on particular area.  it is tensor quantity  unit : N/mm2 Strain : Change in length to original length when force applied on body. it has no unit. Strength of Material Tensile : when body is subjected to equal and opposite pull. Compres

Important points of Engineering Mechanics Force = Newton 1 kgf = 9.8 N Process of finding force = Co position Vector method =  Polygon law force Resultant force = sq.root (2P) sigma H = Equilibrium Sigma R = Not Equilibrium Mass Moment of Inertia = kg-m2 Movement of inertia = m4 Important points of Engineering Mechanics Moment of inertia rectangle to width = (1/12)bd3 Moment of inertia rectangle to depth = (1/12)db3 Moment of inertia sphere = (a4)/12 Moment of inertia of circle about diameter = (pi/64)d4 Moment of inertia of circle about axis = (pi/32)d4 Moment of inertia triangle about base = (bh3)/36 Moment of inertia triangle about axis = (bh3)/12 Moment of inertia solid sphere = (2mr2)/5 Ideal machine efficiency = 100% Non reversible machine =  self locking Reversible machine <50% Non reversible machine >50% Screw jack is non reversible machine Low power machine (P) = mW +  c , P=effort , W= Load Maximum advantage lifting machine = (1/m) M

Engineering Mechanics                                                              Branch of engineering science which deals with principle of mechanics and application of engineering problems There 2 types of Mechanics 1. Static mechanics : it Deals with force and there effect which deals at rest. 2. Dynamic mechanics :  it Deals with force and there effect which deals at motion.          in dynamic there are 2 types  Kinetics :  it Deals with force and there effect which deals at motion due to application of force Kinematics :  it Deals with force and there effect which deals at motion without taking in account force which responsible for motion.  Force : it produce or tends to produce , destroy of tends to destroy the motion of body, which acting on body. Resultant force: it can be define by 3 system Parallelogram law of force  Triangle law of force Polygon law of force Co planer force: W hoes line of action lies on the same plane. Concurren

  Limit  fit & Tolerance : Unilateral tolerance :variation is only one direction Bilateral tolerance : variation on both side  Fundamental deviation: basic size Tolerance = upper limit - lower limit :Permissible limit of variation for manufacturing is assigned to parts for manufacturing purpose as boundary of acceptable build.  Basic size : Nominal diameter of shaft or hole it is same for both Fit : it is clearance between two mating parts, it can be determined by whether the parts move, temporary joint  ,permanent joint. Clearance fit : Hole is larger than shaft. Transition fit : Hole is fractionally smaller than shaft. Interference fit : Hole is smaller than shaft. Functional dimension : have to be machined and fit  with other mating parts. Drilling :  unilateral Dimension  BIS (Bureau of International Standard) Grade of Tolerance :18 Fundamental tolerance : 25 BSI (British standard System) Grade of Tolerance :16 Fundamental t

Engineering Drawing Engineering Drawing is an Universal Language of Engineers to transfer Ideas. Here there are lots of Different type of Sketch (projection) you can differentiate. Prospective Projection :approximate  representation view as you see by eye Auxiliary View : use full in dislocation of portion (X-RAY) Orthographic projection : visual ray line , parallel to each other obliq and axonometric view s : 3 view drawing 3 Principle plane Frontal Horizontal Profile Sphere has only ONE VIEW Europe usually use : First angle view Protector : 0.5 Degree Smallest Angle Drafting Scale: Triangle is not available Light Weight pencil : H  Drawing sheet Ration : 1: root2 Elevation = Top view Elevation on Vertical Plane SHEET A5 : 148 X 210 A4 : 210 X 297 A3 : 297 X 420 A2 : 420 X 594 A1 :594  X 841 A0 : 841 X 1189 Letter in Dwg : 7:4 3H,4H Pencil for : Center line PENCIL  IN ORDER : 18   Light Dark 9H,8H,7H,6H,5H,4H,3H,2H,H,F,HB,B,2B,3B,4B,5B,6B