The structures subjected to seismic excitation can undergo inelastic deformation cycles. The resulting cumulative damage process reduces the ability of the structure and components to withstand future loads. Yet, present design methods focus on either the maximum ductility or the peak ground acceleration, ignoring the nonmaximum cycles of response. The 'absolute' and the 'relative' energy equations were computed by integrating the equations of motion, to include the nonmaximum cycles of response. The energy dissipation and the inelastic behavior of SDOF structures during strong excitation are investigated. The energy dissipation in inelastic structures, modeled as SDOF oscillators subjected to seismic loads, has been studied. The two inelastic models used were the bilinear and the stiffness degrading.
In this study, two damage measures are described, one based on Miner's linear damage model and the other based on energy concepts derived from low-cycle fatigue theory. These methods permit one to evaluate damage based not only on ductility principles, but also on the repetitive cyclic nature of the deformation response.
