In the last form of the Ramberg–Osgood model, the hardening behavior of the material depends on the material constants α α and n . Due to the power-law relationship between stress and plastic strain, the Ramberg–Osgood model implies that plastic strain is present even for very low levels of stress. Nevertheless, for low applied stresses and for the commonly used values of the material constants α α and n , the plastic strain remains negligible compared to the elastic strain. On the other hand, for stress levels higher than σ σ 0 , plastic strain becomes progressively larger than elastic strain.