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This paper proposes a quasi-zero stiffness (QZS) isolator composed of a curved beam (as spider foot) and a linear spring (as spider muscle) inspired by the precise capturing ability of spiders in vibrating environments. The curved beam is simplified as an inclined horizontal spring, and a static analysis is carried out to explore the effects of different structural parameters on the stiffness performance of the QZS isolator. The finite element simulation analysis verifies that the QZS isolator can significantly reduce the first-order natural frequency under the load in the QZS region. The harmonic balance method (HBM) is used to explore the effects of the excitation amplitude, damping ratio, and stiffness coefficient on the system's amplitude-frequency response and transmissibility performance, and the accuracy of the analytical results is verified by the fourth-order Runge-Kutta integral method (RK-4). The experimental data of the QZS isolator prototype are fitted to a nine-degree polynomial, and the RK-4 can theoretically predict the experimental results. The experimental results show that the QZS isolator has a lower initial isolation frequency and a wider isolation frequency bandwidth than the equivalent linear isolator. The frequency sweep test of prototypes with different harmonic excitation amplitudes shows that the initial isolation frequency of the QZS isolator is 3 Hz, and it can isolate 90% of the excitation signal at 7 Hz. The proposed biomimetic spider-like QZS isolator has high application prospects and can provide a reference for optimizing low-frequency or ultra-low-frequency isolators. [ABSTRACT FROM AUTHOR]

Ship vibration not only causes safety issues, but also easily generates noise pollution. Therefore, this paper introduces the quasi-zero stiffness (QZS) vibration isolator to solve the problem of low-frequency vibration. In terms of static analysis, this paper proposes a discretized beam constraint model (DBCM) to study the static properties of flexible beams with large deformation, and the finite element analysis (FEA) verifies the accuracy of DBCM. Regarding dynamic analysis, this paper combines the harmonic balance method (HBM) and the pseudo-arc length method (PALM) to analyze the dynamic response and explore the influence of excitation and damping ratio on the response stability. In addition, the performance of equivalent linear isolators is compared, revealing significant advantages of QZS isolator in terms of isolation bandwidth and peak transmissibility. The experimental data demonstrates that QZS isolator's initial isolation frequency (2.14 Hz) is 68.5% lower than that of linear isolators (6.79 Hz), and the isolation efficiency at 5.35 Hz can reach 90%, making it suitable for low-frequency isolation. Furthermore, experimental data validate the accuracy of the theoretical model and FEA. The static and dynamic theoretical models can optimize the structural parameters of flexible beams and serve as valuable inspiration and reference for designing and improving isolator. • The QZS isolator is composed of eight flexible beams and a linear spring. • DBCM can accurately calculate the nonlinear statics of flexible beams. • The QZS isolator has a wider isolation frequency band and lower transmissibility. [ABSTRACT FROM AUTHOR]