Numerical analysis of multi-degree of freedom isolation structures with ER dampers

The base isolation control analysis of multi-degree of freedom structures(MDOFs) with electrorheological(ER) smart device was carried out. The restoring force model of ER damper has been developed after designing the details of the device. The dynamic characteristics of isolated system were analyzed on the basis of the friction mechanism. Then, the equations and criteria were given for each vibration stage of the isolated system and the corresponding nonlinear analysis program was made. The dynamic time-history analysis was conducted for two MDOFs isolated with ER devices of three different hysteretic rules. The analysis indicated that good control effect could be achieved by reducing the displacement of the isolated system. And the structural acceleration could be reduced significantly with the displacement-limited ER isolator. The acceleration response of structure with pseudo-friction type isolator might be enlarged.