universal testing machines

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Presentation On Universal Testing Machine

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Page 1: Universal testing machines

Presentation On

Universal Testing Machine

Page 2: Universal testing machines

M Waqas Mushtaq MME-12-11 Muhammad Zubair MME-12-29 M. Faisal Maqsood MME-12-20 Muhammad Ahmad MME-12-14 Gulfam Hussain MME-12-30 Arif Ali MME-12-01

Group No 1

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Mechanics Of materials: Mechanics of materials is a branch of mechanics that develops relationships between the external loads applied to a deformable body and the intensity of internal forces acting within the body as well as the deformations of the body. Stress Strain

Introduction

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Stress Strain Diagram

Proportional limit

Elastic limit Yield Point Yield Strength Necking point Rupture Point

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Necking & Rupture

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Universal Testing Machine

The results from the test are commonly used to select a material for an application, for quality control, and to predict how a material will react under other types of forces. Properties that are directly measured via a tensile test are ultimate tensile strength, maximum elongation and reduction in area. From these measurements the following properties can also be determined: Young's modulus, yield strength, and strain-hardening characteristics.

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Tensile Test Compressive Test Tortion Test Shear Bending

Test Function

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COMPONENTS

Load cell Cross head Output

device Test fixtures

(jaws) Extensomete

r Columns

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TYPES

Mechanical The electromechanical machine

uses an electric motor, gear reduction system and one, two or four screws to move the crosshead up or down

. A range of crosshead speeds can be achieved by changing the speed of the motor.

A microprocessor based closed-loop servo system can be Implemented to accurately control the speed of the crosshead.

Hydraulic A hydraulic testing machine uses

either a single- or dual-acting piston to move the crosshead up or down.

In a manually operated machine, the operator adjusts a needle valve to control the rate of loading. In a closed-loop hydraulic servo system, the needle valve is replaced by an electrically operated servo-valve for precise control.

In general, the electromechanical machine is capable of a wide range of test speeds and long crosshead displacements, whereas the hydraulic machine is a cost-effective solution for generating high forces.

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TYPES

Digitally operated Universal Testing Machine

Computer operated Universal Testing Machine

Single Column Universal Testing Machines

Double / Dual Column Universal Testing Machines

Four Column Universal Testing Machines

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It works on the principle of elongation and deformation.

In UTM Tensile, Compressive and Shear Forces are acting.

Working Principle

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Working Procedure Compression Test

In compression test the specimen is gripped in machine jaws and load is applied through a screw gear mechanism by a movable crosshead jaw when we apply load our specimen is compressed under load and its compressive strength shows on screen by graph.

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In tensile test the specimen is gripped in machine jaws and load is applied through a screw gear mechanism by a movable crosshead jaw when we apply load our specimen is elongated under load and stress strain graph is shown on screen.

Tensile Test

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TENSILE TEST

Step 1: Original shape and size of the specimen with no load.

Step 2: Specimen undergoing uniform elongation.

Step 3: Point of maximum load and ultimate tensile strength.

Step 4: The onset of necking (plastic instability).

Step 5: Specimen fractures. Step 6: Final length.