M Waqas Mushtaq MME-12-11Muhammad Zubair MME-12-29M. Faisal Maqsood MME-12-20Muhammad Ahmad MME-12-14Gulfam Hussain MME-12-30Arif Ali MME-12-01Group No 1
Mechanics Of materials:Mechanics of materials is a branch of mechanics thatdevelops relationships between the external loadsapplied to a deformable body and the intensity ofinternal forces acting within the body as well as thedeformations of the body.StressStrainIntroduction
Stress Strain DiagramProportional limitElastic limitYield PointYield StrengthNecking pointRupture Point
Necking & Rupture
Universal Testing MachineThe results from the test arecommonly used to select a materialfor an application, for quality control,and to predict how a material willreact under other types of forces.Properties that are directly measuredvia a tensile test are ultimate tensilestrength, maximum elongation andreduction in area. From thesemeasurements the followingproperties can also be determined:Youngs modulus, yield strength, andstrain-hardening characteristics.
Tensile TestCompressive TestTortion TestShearBendingTest Function
TYPESMechanicalThe electromechanical machine uses anelectric motor, gear reduction systemand one, two or four screws to move thecrosshead up or down. A range of crosshead speeds can beachieved by changing the speed of themotor.A microprocessor based closed-loopservo system can be Implemented toaccurately control the speed of thecrosshead.HydraulicA hydraulic testing machine uses either asingle- or dual-acting piston to move thecrosshead up or down.In a manually operated machine, theoperator adjusts a needle valve to controlthe rate of loading. In a closed-loophydraulic servo system, the needle valve isreplaced by an electrically operated servo-valve for precise control.In general, the electromechanical machineis capable of a wide range of test speedsand long crosshead displacements, whereasthe hydraulic machine is a cost-effectivesolution for generating high forces.
It works on the principle of elongation anddeformation.In UTM Tensile, Compressive and Shear Forces areacting.Working Principle
Working ProcedureCompression TestIn compression test thespecimen is gripped inmachine jaws and load isapplied through a screwgear mechanism by amovable crosshead jawwhen we apply load ourspecimen is compressedunder load and itscompressive strengthshows on screen by graph.
In tensile test the specimen is gripped in machinejaws and load is applied through a screw gearmechanism by a movable crosshead jaw when weapply load our specimen is elongated under load andstress strain graph is shown on screen.Tensile Test
TENSILE TESTStep 1: Original shape and sizeof the specimen with no load.Step 2: Specimen undergoinguniform elongation.Step 3: Point of maximum loadand ultimate tensile strength.Step 4: The onset of necking(plastic instability).Step 5: Specimen fractures.Step 6: Final length.