<P> A universal testing machine (UTM), also known as a universal tester, materials testing machine or materials test frame, is used to test the tensile strength and compressive strength of materials . An earlier name for a tensile testing machine is a tensometer . The "universal" part of the name reflects that it can perform many standard tensile and compression tests on materials, components, and structures (in other words, that it is versatile). </P> <P> Several variations are in use . Common components include: </P> <Ul> <Li> Load frame - Usually consisting of two strong supports for the machine . Some small machines have a single support . </Li> <Li> Load cell - A force transducer or other means of measuring the load is required . Periodic calibration is usually required by governing regulations or quality system . </Li> <Li> Cross head - A movable cross head (crosshead) is controlled to move up or down . Usually this is at a constant speed: sometimes called a constant rate of extension (CRE) machine . Some machines can program the crosshead speed or conduct cyclical testing, testing at constant force, testing at constant deformation, etc . Electromechanical, servo - hydraulic, linear drive, and resonance drive are used . </Li> <Li> Means of measuring extension or deformation - Many tests require a measure of the response of the test specimen to the movement of the cross head . Extensometers are sometimes used . </Li> <Li> Output device - A means of providing the test result is needed . Some older machines have dial or digital displays and chart recorders . Many newer machines have a computer interface for analysis and printing . </Li> <Li> Conditioning - Many tests require controlled conditioning (temperature, humidity, pressure, etc .). The machine can be in a controlled room or a special environmental chamber can be placed around the test specimen for the test . </Li> <Li> Test fixtures, specimen holding jaws, and related sample making equipment are called for in many test methods . </Li> </Ul> <Li> Load frame - Usually consisting of two strong supports for the machine . Some small machines have a single support . </Li>

Types of universal testing machines and principles of operations