Cyclic Plasticity with an Application to Extremly Low Cycle Fatigue of Structural Steel

Abstract

In the present paper the Preisach model of hysteresis is applied to model cyclic behavior of elasto-plastic material. The problem of axial loading of rectangular cross section will be studied in details. Hysteretic stress -strain loop for prescribed history of stress change is plotted for material modeled by series connection of three unite element. All obtained results clearly show advantages of the Preisach model for describing cyclic behavior of so called stable plastic material. Other effects such are racheting and creep will be studied elsewhere. In this paper extremely low cycle fatigue will also be examined. Extremly low cycle fatigue stands for number of cycles to failure in between 10 and 20. The stress level is larger than the yield stress and the plastic strain is of the same magnitude as the elastic strain. In this paper it is shown that this case is of importance to dampers applied for reconstruction of earthquake damaged structures.