Characteristics of Luders deformation and their computer simulation based on a work-softening model

We proposed a new constitutive equation to explain the Portevin-LeChatelier effect. In the present study, we have examined whether the equation is applicable to the yield point phenomena of low carbon steels or not. By using the constitutive equation, some characteristics of the yield point phenomena, i.e., 1. stress difference between upper and lower yield points, 2. yield point elongation, 3. strain rate in Luders band and 4. velocity and width of the band, were predicted. To determine these characteristics experimentally, tensile tests on low carbon steels were carried out at room temperature at various strain rates. Local strains were measured by using strain gage stuck on the specimen surface. The prediction based on the constitutive equation showed a good agreement with the experimental phenomena. Some discussions are also done regarding on the validity of assumptions adopted.