A Study on the Effectiveness in Reducing Seismic Demand due to Targeted Element Ductility of Mechanical System Support Structure

Abstract

An analytical evaluation of the effect of the plastic deformation of the support structure of mechanical components on reducing the seismic demand of the equipment is attempted using a simple two-masses model. The element ductility factor of the support structure is varied stepwise, and changes in the resonance curves of the sinusoidal acceleration wave input and the elasto-plastic seismic response curves of the strong-motion recorded waveform input are examined. Although a relatively small target element ductility factor is set in this report, which aims at a simplified seismic design method in the plastic region, it was observed that the seismic demand decreases significantly from the elastic state by slight plasticization of the support structure element, and the response spectrum becomes flat even in the resonance with the input motion and in the rigid region.