The basic idea of a tensile test is to place a sample of a material between two fixtures ... Measure the change in length while adding weight until the part begins to stretch and finally breaks. The ...

A neck is formed in a tensile test specimen when the UTS of the engineering stress/strain curve is reached. Prior to this stress-strain condition the plastic deformation occurs throughout the sample ...

It doesn't consider the fact that the dimensions of the test specimen change throughout the duration of the tensile test. In this video I cover the interesting topic of true stress and true strain ...