Universal testing machine

Universal Testing Machine (UTM), also known as universal testing machine, material testing machine or material testing rack, is used to test the tensile strength and compressive strength of materials.The early name of the tensile testing machine was the tensiometer.The "general purpose" part of the name reflects that it can perform many standard tension and compression tests on materials, components and structures (in other words, it is general purpose).

Components 

Several variants are in use.Common components include:

Load Frame-usually consists of two strong machine supports.Some small machines have only one stand. Load Cell  Requires a force sensor or other method of measuring load.Regulatory regulations or quality systems often require periodic calibration.Crosshead-A movable crosshead (crosshead) is controlled to move up or down.Usually this is done at a constant speed: sometimes called a constant elongation (CRE) machine.Some machines can program the crosshead speed or do cyclic testing, constant force testing, constant deformation testing,etc. Use electromechanical, servohydraulic, linear drives and resonance drives.Methods of Measuring Extension or Deformation.Many tests require measuring the specimen's response to beam movement. Sometimes an extensometer is used.Output device-needs a way to provide test results.Some older machines have dial or digital displays and chart recorders.Many newer machines have a computer interface for analysis and printing.Conditioning-Many tests require controlled conditioning (temperature,humidity, pressure, etc.).The machine can be tested in a controlled room or in a special environmental chamber placed around the test sample.Many test methods require test fixtures, specimen holders and associated sample making equipment.

Uses

Setup and use are specified in test methods, usually published by standards organizations.This specifies sample preparation, fixtures, gauge length (the length being studied or observed), analysis, etc.The specimen is placed in the machine between the grips, and if required, the extensometer can automatically record the change in gauge length during the test.If no extensometer is installed, the machine itself can record the displacement between the crossheads on which it holds the specimen.However, this method records not only changes in specimen length, but also all other extension/elastic components of the testing machine and its drive system, including any slippage of the specimen in the grips.After the machine starts up, it begins to apply an increasing load to the sample. Throughout the test, the control system and its associated software record the load and tension or compression of the specimen.Machines range from very small benchtop systems to systems with capacities in excess of 53 MN (12 million lbf).