Evaluation of the Relative Plastic Work Factor During the Fatigue Test

The evaluation of the temperature rising during a fatigue test is extremely important to define the energy method to be used. In order to define the best load program and the more appropriate test frequency, it is necessary to estimate the surface temperature of the material, in particular when it's needed to arrange some tests on mechanical components. With regards to the energetic approach to the study of fatigue phenomena, in the past the internal damping factor was considered an important parameter to define the fatigue quality of the material used for the mechanical application. In the present paperthe role of another important work parameter ishighlighted, when linked to the plastic strain caused by the high number of fatigue tests. An approach to the detection of first microplasticization and crack beginning is also proposed, with a model for the estimation of the crack propagation during the last cycles of fatigue test.