Although there can be many variations on the standard tensile test, a tensile test most often involves loading a test specimen in a universal testing machine and applying an increasing uniaxial load to the specimen until failure occurs. The sample can be supported in the test frame any number of ways: hydraulic grips, mechanically fastened clevis grips or threaded grips. The method of gripping most often depends on the material being tested, its geometry and the capabilities of the test frame.
The test frame is designed to elongate the sample at a constant rate while accurately measuring the applied load. The load is measured using a load cell attached both to the test frame and the test specimen through a mechanical assembly. The recorded load data can be used to calculate the engineering stress using the formula: