Papers by Author: Antonino Risitano

Abstract: The paper presents a study performed on steel specimens under static loading using thermal infrared techniques to determine whether thermal analysis can also provide information on the fatigue behavior. In particular, the traditional static elastic zone was investigated. The results highlight that, even in the macroscopically elastic phase, a variation from the theoretical behavior is also detectable using thermographic techniques. In some previous works the authors demonstrated the possibility to estimate the fatigue limit of the material by mean of static tensile tests. In this paper, the procedure is adopted to analyze the effect of the cross-head speed on the thermoelastic limit, confirming the possibility to define the fatigue limit as the end of the totally linear thermoelastic behavior.

Abstract: In this work is indicated how it could be possible to evaluate the limit stress of the thermo-elastic phase of deformation by thermo-analysing the surface of the specimen during a static traction test. Adding the temperature curve measured on a small area of the surface (the hottest) to the classic stress-strain curve, it is possible to evaluate a limit temperature T0 coincident with the beginning of the non linear trend of the curve. The corresponding stress value is coincident with the fatigue limit of the analyzed component. As an example, the results of traction tests performed on two notched specimens, where the change of linearity in the temperature curve during static traction test was evident, are reported.