Abstract
An intelligent universal test machine can measure the relationships between stress and time, and strain and time. The tensile test of the indistinguishable yield point of S45C was carried out using the intelligent universal test machine. The relationship between stress and time showed three different types of behavior, types A, B and C, depending on the elevated tensile speed. For type A, no clear elasticity-plasticity transition point (E-P point) is observed. For type B, an E-P point is clearly observed. For type C, an E-P point is also observed, but elastic behavior appears in the plastic region. The results of the experiment were analyzed by considering the relationship between strain and time in the plastic region, which is shown to be linear. We conclude that the slope of the experimentally determined equation is dependent on the material, and the graft is dependent on the elevated tensile speed.
