218 / 2021-04-07 10:07:04

An innovative multi-dimensional base isolation device for urban overpass

Vibration; base isolation; multi-dimensional; urban overpass; COMSOL

Under the vehicle loads or earthquake actions, the urban overpass could sustain severe vibration, thus it leads to serviceability or safety issue. To overcome this, the traditional measure is to install steel spring or rubber bearing as base isolation devices. However, these conventional isolators possess limited energy dissipation capacity. Moreover, they are mainly used to isolate the vertical vibration only. Therefore, it is quite meaningful and urgent to develop an isolator with excellent energy dissipation capacity in both vertical and lateral directions. In this study, we proposed an innovative isolator consisting of vertical and lateral subassemblies, which reduce the vertical and lateral vibration, respectively. The vertical subassembly is mainly composed of piezoelectric ceramic, magnetorheological (MR) fluid, shape memory alloy (SMA) disc spring, permanent magnet, coil and electrical resistor. The lateral subassembly contains piezoelectric ceramic, electromagnet, MR fluid and SMA spring. The isolator fully employs and integrates the piezoelectric effect, shape memory effect, eddy current and MR damping. As the energy dissipation mechanism involves multiple physical fields such as elasto-dynamics and electro-magneto-mechanics, the COMSOL Multiphysics software is used to simulate the dynamic behavior of the new isolator. The numerical results indicate that the isolator has superior multi-dimensional energy dissipation capacity, thus it has great potential to reduce the vibration of the urban overpass and other kinds of structures.