Abstract
Most of the passive control devices currently used for buildings can be categorized into a velocity-dependent (visco-elastic or viscous) device and a displacement-dependent (elasto-plastic or friction) device. The former tends to increase acceleration and inertia force in a major earthquake, and the latter does not dissipate kinetic energy in a small quake. In order to overcome these limitations, we have developed a visco-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-elastic constitutive rule and a bilinear elasto-plastic constitutive rule, and it appears to correlate extremely well with the test results. Simplified expressions for deformations of both devices as well as effective stiffness and damping of the combined damper are also given.
