On the premise of a small excitation amplitude, the performance of the quasi-zero stiffness isolator is better than that of the corresponding linear vibration isolator. 20 studied the dynamic characteristics of the quasi-zero stiffness isolator based on a simplified model. The concrete realization of negative stiffness can be realized in a variety of mechanisms. The basic principle of quasi-zero stiffness is to introduce a negative stiffness structure into a positive stiffness system. The QZS isolator 18 is a typical vibration isolator with high static stiffness and low dynamic stiffness, which can provide sufficient static stiffness and low dynamic stiffness near the equilibrium point. In the past ten years, the quasi-zero stiffness (QZS) vibration isolator is the most representative one with high static and low dynamic characteristics. The directional magnetic field can align the particles to form a columnar structure and obtain an anisotropic MRE. The curing process was carried out in a 240 MT oriented magnetic field for about 6 h. Then, a uniform mixture was put into the mold with a cylindrical cavity with a diameter of 20 × 1 mm 2. All ingredients were stirred in a blender at room temperature for 30 min. A typical method is to mix silicone rubber and dimethyl silicone oil with a stirring rod at room temperature and then mix with cobalt particles. Liu 17 prepared an MR elastomer with excellent performance according to previous research results. The preparation method of MRE samples is simple. The working range of MRE and MRF is also different. Better thermal stability is another advantage of MRE. 16 In addition, in the case of MRF, agglomeration and sedimentation of magnetic particles are no longer a problem. This is because of the densification of the fluid after many operating cycles, and the durability of the MRF is limited.
11–15 The magnetorheological elastomer (MRE) is the corresponding material of MRF curing. 9,10 Compared with a magnetorheological fluid, the magnetorheological elastomer does not have the problems of particle sedimentation and sealing difficulty, so it has been more applied in different fields. The final performance of the composite mainly depends on the component material, quantity, and combination method used. Under the condition of magnetic field control, the stiffness and damping can change continuously. The mechanical properties of the magnetorheological elastomer change with a change in the magnetic field strength 5–8 and have fast response and reversibility. The magnetorheological elastomer is formed by evenly dispersing ferromagnetic particles in various types of rubber and then curing. Its performance is similar to that of a magnetorheological fluid (MRF). The magnetorheological elastomer (MRE) 1–4 is a kind of intelligent material, which has very excellent performance and is widely used in various fields.
The experiment results show that the theoretical calculation results are in good agreement with the actual shock isolation bearing, and the proposed model can accurately describe the dynamic characteristics of the SIBP, which provides the design basis for the application of the SIBP in active control. A novel dynamics model is established to model the displacement–force hysteretic curve of the SIBP under small displacement and large displacement input. The shear storage modulus and damping factor of MRE with different strains are tested and analyzed. Through the theoretical analysis and magnetic field simulation of the SIBP’s damping force, the structure of the SIBP is designed and established. It is noteworthy that the stiffness of the magnetorheological elastomer (MRE) limit layer can be adjusted to provide controllable seismic resistance and to achieve isolation and vibration reduction under various seismic conditions, such as small and large displacements. The addition of the negative stiffness platform to the SIBP can further reduce the natural frequency of the structure and enable the isolator to a broader range of isolation frequencies. In this paper, an intelligent shock isolation bearing based on the negative stiffness platform (SIBP) is designed, manufactured, and modeled.
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