Base Isolator of Vertical Seismic Vibration Using a Negative Stiffness Mechanism

Mochida, Yusuke; Kida, Naohiro; Ilanko, Sinniah

doi:10.1007/978-3-319-09918-7_99

Cited by 4 publications

(2 citation statements)

References 9 publications

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“…Sarlis introduced a preloaded linear elastic spring into the passive isolation system and provided the damping system with negative stiffness by mounting an anchor frame and a movable frame [6]. Because the preloaded linear spring combination can provide negative stiffness by a certain connection method, Mochida et al hinged three linear springs to form a combination that can be applied to foundation isolation, which provides negative stiffness [7]. Mizuno et al used a voice coil motor as a linear actuator to generate a suspension system with negative stiffness and a pair of plate springs with normal stiffness and damping; the control strategy based on the Laplace transform was also introduced [8].…”

Section: Introductionmentioning

confidence: 99%

Performance of Variable Negative Stiffness MRE Vibration Isolation System

Guo

et al. 2015

Advances in Materials Science and Engineering

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Magnetorheological elastomer (MRE) vibration isolation devices can improve a system’s vibration response via adjustable stiffness and damping under different magnetic fields. Combined with negative stiffness design, these MRE devices can reduce a system’s stiffness and improve the vibration control effect significantly. This paper develops a variable negative stiffness MRE isolation device by combining an improved separable iron core with laminated MREs. The relationship between the negative stiffness and the performance of the device is obtained by mathematical transformation. Its vibration response under simple harmonic excitation at small amplitude and the impact of the volume fraction of soft magnetic particles on the isolation system are also analyzed. The results show that the negative stiffness produced by the magnetic force is a major factor affecting the capacity of the isolation system. Compared to devices of the same size, the isolation system equipped with low-particle volume fraction MREs demonstrates better performance.

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Section: Introductionmentioning

confidence: 99%

Performance of Variable Negative Stiffness MRE Vibration Isolation System

Guo

et al. 2015

Advances in Materials Science and Engineering

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“…This is because larger negative stiffness reduces the bearing capacity while isolating the seats from vibration coming from road profiles. Mochida et al [17] also investigated the use of negative stiffness in reducing transmission of forces in structures and suggested its use for seismic isolation, but the analysis was limited to the static case, and they did not conduct a dynamic analysis. Systems that provide such varying stiffness are called High-Static-Low-Dynamic Stiffness Systems (HSLDSS).…”

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confidence: 99%

Experimental and numerical investigation of a vertical vibration isolator for seismic applications

et al. 2022

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In near-fault seismic zones, the vertical acceleration experienced during a strong event can be greater than horizontal acceleration. Methods to reduce horizontal acceleration are applied in various forms and are in common use. However, methods to reduce vertical acceleration, and practical protection systems for these applications, remain elusive. One strategy to protect structures, which has been demonstrated to be effective in situations where the excitation is horizontal, is to isolate the structure. For vertical excitations, this is difficult due to the need to maintain sufficient stiffness and strength in the direction of gravitational loads. The need to maintain high stiffness for gravity loading while allowing flexibility for isolation during earthquakes has led to research on the use of High-Static-Low-Dynamic Stiffness Systems (HSLDSS) and in particular Quasi-Zero Stiffness Systems (QZSS), which have zero equivalent stiffness in the equilibrium position. Although effective, the QZSS is sensitive to mistuning and prone to large deformations for relatively small increments in static load for building applications. This paper presents the results of an analytical and experimental study in which a HSLDSS isolation system carrying a payload is subject to vertical base excitation using sinusoidal as well as actual, scaled earthquake signals. Static loading tests are also presented. This isolation system consists of rigid rotating arms, horizontal and vertical springs and a vertical damper. By a suitable selection of parameters this could also serve as a QZSS. Results show that both the QZSS and HSLDSS can significantly reduce the magnification of the force as well as the transmission of the acceleration and that the HSLDSS retains stiffness at the equilibrium position. The numerical model includes friction and is solved using direct integration of the equation of motion. Experimental results from a scale model agree well theoretical predictions.

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Feasibility and design of nonlinear negative‐stiffness isolating approach for solid‐rocket‐motor‐type structures

Wang,

Gao,

Wang

et al. 2024

Engineering Reports

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Solid rocket motor (SRM)‐type structures are popular due to their reliability, considering that service safety during transportation can be improved by applying advanced vibration control technologies. In this study, a negative‐stiffness‐enhanced isolation system (NSeIS) with appropriately designed linear and nonlinear properties was developed to vertically isolate SRMs subjected to transportation‐ and deployment‐induced vibrations. The NSeIS design, based on the combination of a negative‐stiffness device and vertical isolator, involved a clear mechanical model, physical realization, and mechanical properties. Parametric analyses were performed on a typical SRM controlled with a linear and nonlinear NSeIS and a conventional isolation system. Subsequently, a feasible parameter domain and design recommendations were deduced. Finally, design cases for the SRM for time‐domain verification were considered. The results revealed that the NSeIS offers a flexible and enhanced isolating effect through the parallel arrangement of the negative‐stiffness device and conventional isolators. For the motor‐type structure, NSeIS ensures marked enhancements in performance and multiple levels of mitigation effects. Thus, compared with a conventional isolator with the same damping, NSeIS achieves a more substantial negative‐stiffness effect for a large displacement response range owing to its nonlinear property. NSeIS can isolate more vibration‐induced energy, thereby suppressing the interface Mises stress, which is essential for SRM‐type structures.

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Base Isolator of Vertical Seismic Vibration Using a Negative Stiffness Mechanism

Cited by 4 publications

References 9 publications

Performance of Variable Negative Stiffness MRE Vibration Isolation System

Performance of Variable Negative Stiffness MRE Vibration Isolation System

Experimental and numerical investigation of a vertical vibration isolator for seismic applications

Feasibility and design of nonlinear negative‐stiffness isolating approach for solid‐rocket‐motor‐type structures

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