Comparison Between Hysteresis Energy and Input Energy for Failure

Many methods for evaluation of seismic resistance have been proposed. Energy balance equation is one of the methods. The main feature of the energy balance equation is that it explains accumulated information of motion. Therefore energy balance is suitable to investigate the influence of cumulative load. We have already conducted some studies that applied the energy balance equation to mechanical structures. In the studies, we confirmed a relationship between input energy and fatigue failure. On the other hand, a relation between fatigue life and hysteresis energy (i.e. area of a hysteresis loop) is well known in the fatigue strength field, and a lot of knowledge has been reported. The input energy of the energy balance equation is essentially equivalent to the hysteresis energy. Therefore it is expected that input energy for failure is equivalent to hysteresis energy for failure. In this paper, two experiments are carried out. One is a fatigue fracture experiment and the other is a vibration experiment that causes fatigue failure to experimental models. Both experiments cause fatigue failure by same bending mode. Finally the input energy and hysteresis energy for failure are compared.