Performance improvement of base isolation systems by incorporating eddy current damping and magnetic spring under earthquakes

Abstract

Summary An innovative subsystem with the incorporation of eddy current (EC) damping and magnetic negative stiffness spring (MNSS) is proposed to develop feasible strategies for performance improvement of existing base isolation techniques. The concept of integrating the eddy current damping mechanism and the nonlinear negative stiffness spring is firstly introduced for better energy transition behavior under earthquake excitations. The analytical expressions of the force characteristics of the EC and the MNSS components are presented accordingly, and a parametric study is conducted to evaluate the inherent properties of the integrated magnetic subsystem. To demonstrate the advantages of the EC–MNSS subsystem, an illustrative example of a two‐DOF model simulating both the superstructure and the isolation layer is numerically investigated by adopting two representative isolators and the proposed subsystem. The EC–MNSS subsystem is illustrated to significantly and simultaneously improve the isolation performances in terms of base drift and structural acceleration. The energy exchange and dissipation behavior are further revealed by employing time history analysis and energy‐displacement‐velocity plots. Furthermore, the proposed EC–MNSS subsystem is implemented in a benchmark isolation problem adopting an eight‐story frame structure subjected to bidirectional earthquake excitations. The simulation results indicate the superior and the comparable performances of the integrated isolation system as compared to those of the passive and the control‐augmented isolations, respectively.

Multi-objective optimization design of novel differential permanent magnet spring based on analytical modeling

“…54–56 Case1 represents that stiffness K is the top priority, linearity L i is the second, and volumetric force G is less important than them, which is suitable for the applications with large stiffness or strong nonlinearity, such as vibration energy harvesters 13,14,49 and nonlinear vibration isolator. 9 The priority from high to low of Case 2 are linearity L i , stiffness K , and volumetric force G , which is suitable for linear machines. 6,7 The priority from high to low of Case 3 are volume force G , linearity L i , and stiffness K , which is suitable for aerospace field.…”

“…4 These characteristics are of great significance in improving vibration and noise, reducing energy consumption, and increasing service life and durability. 5 Therefore, PMS are widely used for motors, 6,7 robots, 8 vibration isolators, 9 static load compensation, 10 pumps, 11 valves, 12 energy harvesting, 13,14 and many other apparatuses.…”

Study on shock absorption performance and damage of a new staggered story isolated system

“…Base isolated system could effectively protect buildings under high intensity ground motion (Losanno et al, 2021), and reduce the seismic response of structure (Cancellara and Angelis, 2016). Researchers have studied many kinds of isolated bearings and found that most of them can not only reduce the seismic response of the structure, but also control the displacement of the isolated story (Castaldo and Tubaldi, 2018; Fu et al, 2019; Shan et al, 2020; Shang and Hu, 2020). For the application of base isolated, Japan has more experiences than other countries (Pan et al, 2005).…”

Seismic Response of Long-Span Staggered Storey Isolated Structure Under Multi-support Excitation

“…Additionally, multi-support excitation for long-span structures is used to ensure that the calculation results are similar to the actual seismic response. The Meilan Airport Phase II Project is the largest staggered isolated building in China, as shown in Figure 1 [1][2][3][4][5][6]. During an earthquake, the energy released by the earthquake is transmitted to the Earth's surface, causing the ground to vibrate.…”