UTM

Universal Testing Machine

1. Universal Testing Machine Maneeb Masood M.Tech.Part-1(15152010 ) IIT(BHU), Varanasi

2. 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

3. 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

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

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

6. 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.

7. LOAD CELL TENSION CROSSHEAD TABLE ADJUSTABLE CROSS HEAD SCREW COLUMN Notched column Hydraulic cylinder CONTROL PANEL

8. 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 Mark the gauge length as per specification and record it accurately. The gauge length should be symmetrical with the length of the bar. Grip the specimen firmly in the jaw of the Universal testing machine and adjust the machine to read zero. Continue loading at increments each time and this loading should be continued till yield point is reached. Record the load at the yield point . That is uniaxial compressive strength of the specimen.

9. 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 Mark the gauge length as per specification and record it accurately. The gauge length should be symmetrical with the length of the bar. Grip the specimen firmly in the jaw of the Universal testing machine in brazilian cage and adjust the machine to read zero. Continue loading at increments each time and this loading should be continued till yield point is reached.

10. Brazilian cage

11. Shear strength:- Steps Mark the gauge length as per specification and record it accurately. The gauge length should be symmetrical with the length of the bar. 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. Continue loading at increments each time and this loading should be continued till yield point is reached. Record the load at the yield point. That is shear strength of the specimen .

12. Double shear cage Single shear cage

13. PRECAUTIONS Apply the load at a uniform rate and without any jerk. S election of proper dimension of specimen when testing of different type of strength.