The yield point, or yield strength is the point on a stress–strain curve where elastic behavior ends and plastic behavior begins. A more simplified definition is that Yielding means the start of breaking of fibers on the sample being tested. If a sample is being tested and the yield point has not been reached the sample will return to its original shape. However, once the yield point has been passed the sample will become permanently deformed. Stress-Strain curve analysis is a critical component of accurately measuring the yield point. United offers a wide range of equipment, including our DATUM software package which will help you perform accurate and repeatable yield testing procedures.