Unit 1 Universal testing machine A Universal Testing

Unit 1 Universal testing machine �A Universal Testing Machine is a machine that is used to perform standard tensile and compressive tests on materials, components and structures. �It can be used to perform following tests: Tensile Test Compression Test Shear Test

COURSE OUTCOMES After the end of this course, students will be able to: Study and perform on universal testing machine to determine tensile, compression and shear strength. Performance on impact testing machine for different materials for determining CO 405. 2 impact strength. Experiment on brinell hardness testing machine to determine the hardness of CO 405. 3 the material. CO 405. 1 CO 405. 4 Experiment on Torsion test Experiment on deflection of beam (Simply supported beam) for determining slope and deflection. CO 405. 6 Experiment on helical spring to determine the deflection of spring CO 405. 5

Introduction �A Universal Testing Machine is a machine that is used to perform standard tensile and compressive tests on materials, components and structures. �It can be used to perform following tests: Tensile Test Compression Test Shear Test

Components. . . �Loading Unit Load Frame Load Cell Cross Head �Control Panel Hydraulic Power Unit Load Measuring Unit �Control Devices Electric Control Devices Hydraulic Control Devices Load Indicating Devices

Control Panel A Control Panel Comprises of: �Power Pack (with drive motor & oil tank) �Control Valves �Pendulum Dynamometer �Load Indicator System �Autograph Recorder

Working Principle It is a load-controlled machine and works on the principle of elongation/deformation of material on the application of load.

TESTS To assess various rock properties we can use different kind of machines among them universal testing machine is one of the most widely used and versatile machine which can measure compressive/tensile/shear strength, directly or indirectly using sample/specimen of rock mass. �Compressive strength can be assessed directly but for the tensile and shear strength we need to use different kind of cages and calculations. �Tension and Shear tests are conducted by indirect testing. �In the Old UTMs, the lower cross head can be raised or lowered rapidly by operating the screwed columns , thus facilitating ease of fixing of test specimen. �New UTMs have a fixed table and the adjustable cross head moves up and down.

TENSION CROSSHEAD Notched column SCREW COLUMN ADJUSTABLE CROSS HEA D TABLE LOAD CELL Hydraulic cylinder CONTROL PANEL

OPERTAIONAL PROCEDURE Compressive strength: Specimen: The cross section of the specimen may be circular, squire, rectangular or in special cases of any other form. Specimens of circular sections are generally be made to the dimensions. Steps 1. Mark the gauge length as per specification and record it accurately. The gauge length should be symmetrical with the length of the bar. 2. Grip the specimen firmly in the jaw of the Universal testing machine and adjust the machine to read zero. 3. Continue loading at increments each time and this loading should be continued till yield point is reached. 4. Record the load at the yield point. That is uniaxial compressive strength of the specimen.

TENSILE STRENGTH: Specimen: The cross section of the specimen may be circular, squire, rectangular or in special cases of any other form. Speimen of circular sections are generally be made to the dimensions Steps 1. Mark the gauge length as per specification and record it accurately. The gauge length should be symmetrical with the length of the bar. 2. Grip the specimen firmly in the jaw of the Universal testing machine in brazilian cage and adjust the machine to read zero. 3. Continue loading at increments each time and this loading should be continued till yield point is reached.

Brazilian cage

Shear strength: - Steps 1. Mark the gauge length as per specification and record it accurately. The gauge length should be symmetrical with the length of the bar. 2. Grip the specimen firmly in the jaw of the UTM in suitable cage for single shear or double shear and adjust the machine to read zero. 3. Continue loading at increments each time and this loading should be continued till yield point is reached. 4. Record the load at the yield point. That is shear strength of the specimen.

Single shear cage Double shear cage

PRECAUTIONS 1. Apply the load at a uniform rate and without any jerk. 2. Selection of proper dimension of specimen when testing of different type of strength.