BEHAVIOR OF A PASSIVE CONTROL DAMPER COMBINING VISCO-ELASTIC AND ELASTO-PLASTIC DEVICES IN SERIES

Most of the passive control devices currently used for buildings can be categorized into a velocity-dependent (visco-elastic or viscous) devi ce and a displacement-dependent (elasto-plastic or friction) device. The former tends to increase acceleration and inertia force in a major e arthquake, and the latter does not dissipate kinetic energy in a small quake. In order to overcome these limitations, we have developed a v isco-elasto-plastic damper combining the two in series. Test results validate superior performance and significant advantages of the damper as compared to a case using a single device. Analysis was also conducted using a model with fractional time-derivative visco-elas tic constitutive rule and a bilinear elasto-plastic constitutive rule, and it appears to correlate extremely well with the test results. Simplified e xpressions for deformations of both devices as well as effective stiffness and damping of the combined damper are also given.