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What is the principle of tensile test

Universal Testing Machine

Universal Testing Machine (UTM) can used for testing Mechanical properties (tension, compression etc.)

By applying tensile stress to a given test specimen, Compression, or transverse tension. What is the principle of the tensile test is the machine What is the principle of the tensile test.

It can named because it can perform a wide range of tests. Can work on a variety of materials. Details of the structure and application can given mostly experimentally. Published by a standards body. It mentions Sample preparation, fixing, measuring length (the length of study or observation), analysis, Etc,,,.

The sample can placed in the machine in between An extensometer can kept if needed The record gauge length changes automatically During the test. If no extensometer can fitted, The machine can record the displacement between itself Its cross heads can sampled. It is This method does not only record changes in the length model but all other expanded plastic Components of the testing machine.

There is a bar machine When starting, an increasing load begins to fall on it model. Control system throughout the test Records associated software loads and Expansion or contraction of the model. Machines From the smallest tabletop systems Except for a capacity greater than 53 MN (12 million lbf). Tests like peel test, flexural test, tension test, bending Test, abrasion test, spring.

Loading unit

The loading unit of UTM consists of the following components:

  • Load frame
  • Upper cross and lower cross
  • length scal

Mounting frame

The load frame of the universal testing machine can constructed with single support or double support.  What is the principle of tensile test The load frame consists of a table (where the specimen for compression testing can placed), an upper cross-section and a lower cross-section.

 Upper crosshead and lower crosshead

The upper cross-section can used to clamp one end of the test specimen. The lower cross member on the load frame can  a movable cross member whose screw can loosened and tightened to adjust the height. Both crosspieces have a thin slot in the center. This slot has a pair of raked jaws whose purpose is to hold the tensile test specimen.

Extension scale

The relative movement of the lower and upper tables can measured by the longitudinal scale supplied with the loading unit.

Control unit

Main components of control unit in universal testing machine:

  • Hydraulic power unit
  • unit of weight
  • Control devices

Hydraulic Power Unit

This unit has an oil pump that provides non-pulsatile oil flow to the main cylinder of the load unit. This flow enables uniform application of loads on the specimen. What is the principle of tensile test The oil pump in the hydraulic power unit can driven by an electric motor and sump.

Unit of measurement of weight

This unit consists of a pendulum dynamometer unit, which consists of a small cylinder with a piston that moves with a non-pulsating flow of oil. The pendulum pivot can connected to the piston by a lever. The pivot lever deflects depending on the load applied to the model. This deflection can converted into load pointer and displayed as load on the dial.

Load measuring unit (0-100 kN; 0-250 kN; 0-500 kN and 0-1000 kN) knob can adjust the range of load application. The accuracy of the unit of measurement controls the overall accuracy of the machine.

Control device

Control devices may be electrical or hydraulic. Electrical controls use switches to move the crossheads and turn the unit on/off. A hydraulic control device consists of two valves, a right control valve and a left control valve or release valve. A right control valve can used to apply loads to the model. Left control valve can used to release load application.

Functions of Universal Testing Machine

Standard tests performed by UTM are:

  • Tensile testing
  • Compression test
  • Adhesion test
  • Pull-out test
  • Bending test
  • Hysteresis test

Tension Test on Steel Wire

UTM can used to test various materials such as concrete, steel, cables, springs, steel wires and chains, slings, links, ropes, pulleys, steel ropes. Also read: Pull out the test What is the principle of the tensile test

UTM provides the value of load application and relative displacement. A load deflection diagram can obtained from the observed values. Load value on the Y axis and displacement on the X axis. Displacement is the movement of cross-sections during load application.

  • Force and displacement (cross-head motion) diagram
  • Force versus displacement (cross-head motion) diagram
  • From the load-deflection diagram, stress-strain analysis, modulus of elasticity, and yield strength of the tested specimen can determined.

Major Parts of Universal Testing Machine

What is the principle of tensile test

  • Upper crosshead
  • Movable crosshead
  • table
  • Load indicator
  • Speed control
  • Place for tensile model
  • Space for abstract models
  • Creation and operation of UTM
  • A universal testing machine consists of two vertical threaded rods.
  • Where the movable cross-section slides on these vertical bars. The cross-section is constant.
  • Both these ends have locking clamps to hold the specimen. Wires, wires, etc. are mostly for tensile testing.
  • If it is a tensile test, the specimen can placed between the cross-head and movable head jaws.
  • If it is a pressure test, the specimen can placed between the moving head and the table.
  • There can a speed controller, which controls the speed of two vertical threaded rods, as a result of which there can a change in the load applied to the sample with the help of a movable cross-section.
  • With the help of the loading dial indicator, you can see how much load can applied to the specimen during the test.

Principle of Operation:

The test specimen can loaded with a hydraulic system and accurately measured with a pendulum dynamometer.

oil pressure in the main cylinder can transmitted to the cylinder of the pendulum dynamometer located in the control chamber, the dynamometer piston exerts a force proportional to the hydraulic pressure. This force can transferred to the pendulum through a lever system. The pendulum displacement actuates the rack and pinion mechanism that drives the load indicator pointer. What is the principle of tensile test The swing speed of the pendulum can effectively reduced to absorb the energy if the sample suddenly breaks.

Tension machine includes:

Tension Unit:

It consists of a hydraulic cylinder and piston mounted on a rigid base. The loading frame consists of an upper cross, a middle cross and a lower table.

The upper cross-section and the lower table can connected by two hollow hard chrome-plated columns. The middle crosshead can mounted on two hard chrome-plated threaded columns. A reduction gear motor drives a chain and sprocket mounted on the bottom of a threaded column to adjust the height—men!

The cylinder and ram can folded separately to eliminate friction. Axial loading of the system can ensured by providing a ball seat under the lower table.

A length scale with a minimum count of 1 mm is provided to measure deformation in various specimens.

The tensile test can conducted by holding the test specimen between the upper and middle cross-sections. Compression, transverse, bending and shear tests can conducted between the middle cross-section and the lower table.

Control Panel:

The control panel includes drive motor, oil sump, hydraulic system with pendulum dynamometer and load indication system.

Hydraulic system

The power pack has a direct-driven pump which generates a maximum pressure of 200 kgf/cm2. The hydraulic pump generates a non-continuous pulsating oil flow. So loading the application is very smooth. An oil filter, oil strainer, air breather, oil level indicator, and drain plug are provided in the power pack. Flow compensating pressure in the master cylinder. This maintains a constant rate of movement of the piston, so the rate of tension remains constant. This valve can be manually operated and provides infinitely variable oil flow to achieve various tension ratios.

Pendulum Dynamometer:

The oil pressure in the master cylinder activates a special dynamometer system. Pressurized oil in the loading cylinder proportionally pushes up the metering piston and deflects the pendulum. The piston can continuously rotated to remove friction. The system has an effective damping arrangement to ensure a smooth return of the pendulum after the sudden breakage of the test piece. This unit allows the selection of favorable hydraulic ratios that produce relatively small frictional forces.

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Load Indication System:

The system has a large dial and a pointer. The pendulum displacement actuates the rack and pinion mechanism, which in turn drives the load indicator pointer. The mouse moves over the large dial indicating the load.  A window-type dial is provided to change the load range easily and clearly.

Load Extend Registration System:

A continuous roll (one strip chart) type load-output recorder is provided to plot the load-output diagram. The horizontal movement of the rack in a ratio of 1:5 or 1:10 produces the graph load coordinate and drum rotation to the ellipse ordinate. Read more

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