Journal articles: 'Friction isolator'

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Mondal, Papiya D., Aparna D. Ghosh, and Subrata Chakraborty. "Performances of Various Base Isolation Systems in Mitigation of Structural Vibration Due to Underground Blast Induced Ground Motion." International Journal of Structural Stability and Dynamics 17, no. 04 (April 6, 2017): 1750043. http://dx.doi.org/10.1142/s0219455417500432.

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A comparative study is carried out on the performance of various elastomeric and frictional base isolation (BI) systems in the vibration mitigation of structures subjected to underground blast induced ground motion (BIGM). The parametric sensitivities of the base isolated structures to variations in the design parameters of the isolators are examined for different intensities of blast input. Results indicate that substantial reductions in both the acceleration and displacement responses of the structure can be achieved by the different base isolators. Generally, the Electricite de France (EDF) base isolator produces higher peak response reductions. However, peak bearing displacements are also largest here. The pure friction (P-F), resilient-friction base isolator (R-FBI) and friction pendulum (FP) systems produce lower values of response reductions but peak bearing displacements as well as residual displacements of isolators are also low. The New Zealand (N-Z) system provides good response reductions with a low to moderate value of peak bearing displacement. The present study indicates how a proper selection of the type of BI system with suitable design parameters can mitigate structural vibration due to different intensities of BIGM and restrict the unwanted characteristics of large isolator displacement and its permanent deformation.

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Lu, Lyan-Ywan, and Chia-Chiea Hsu. "Eccentric Rocking Bearings with a Designable Friction Property for Seismic Isolation: Experiment and Analysis." Earthquake Spectra 29, no. 3 (August 2013): 869–95. http://dx.doi.org/10.1193/1.4000166.

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The friction coefficient plays a critical role in a friction-type isolator, since it determines the transmitted seismic force and the energy dissipation capacity of the isolator, simultaneously. However, the choice of feasible sliding materials that possess appropriate friction coefficients is very limited, and this has restricted the development and applications of friction-type isolators. To overcome this, an isolator called the eccentric rocking bearing (ERB) with the property of designable friction is introduced in this study. By using an eccentric rolling mechanism, the ERB bearing is self-centering and its effective friction coefficient is adjustable by a geometric parameter that can be designed by engineers. The results of a shaking table test conducted on an ERB-isolated full-scale structure have confirmed the feasibility and efficiency of the ERB bearings for seismic isolation. Additionally, the high consistency between the simulated and experimental dynamic responses verifies the method developed to analyze the ERB.

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Hou, Jun Fang, Rong Li Li, Guang Chun Yu, Tao Luo, and Hai Wen He. "Contrast Test Research on Application of Dry Friction Isolators to Vibration Isolation of Vehicle Electronic Devices." Applied Mechanics and Materials 505-506 (January 2014): 360–64. http://dx.doi.org/10.4028/www.scientific.net/amm.505-506.360.

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As regards the reliability of the vehicle electronic devices on the tracklayer getting worse due to severe vibration, isolation theory and mechanical model of the GWF vibration isolator and wire-mesh vibration isolator were analyzed, and the test research on the isolation effectiveness of the two isolators applied to the isolation of the vehicle electronic devices were carried out. The test results show that the vibration source of the foundation of the electronic device is mainly from the structure resonance, and the two dry friction vibration isolators exhibit excellent isolation effectiveness on different roads and at different speed. The wire-mesh vibration isolator shows better performance than GWF vibration isolator on three-dimensional comprehensive isolation.

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Zhang, Wei, Xiaoping Li, Jian Li, and Xiqiu Li. "An Improved Structural Analysis Method for Isolator with Quasi-Zero-Stiffness Characteristic." Shock and Vibration 2021 (December 15, 2021): 1–13. http://dx.doi.org/10.1155/2021/9920674.

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A typical quasi-zero-stiffness (QZS) vibration isolator consisting of a vertical spring and two oblique springs has been widely researched on its static and dynamic characteristics. A general criterion for determining structural parameters of QZS isolator is to achieve low nondimensional stiffness around the equilibrium position. However, lower nondimensional stiffness of linear isolator means lower isolation frequency, which may be invalid on QZS isolator. Because there is an implicit relationship between geometric parameter and stiffness ratio of QZS isolator, this study presents an improved optimization criterion for determining the optimal structural parameters of the typical QZS isolator. The optimization criterion is that the QZS isolator has the maximum displacement range around the equilibrium position without exceeding given natural frequency, rather than given nondimensional stiffness. The results show that isolator with these optimal parameters can achieve lower stiffness around the equilibrium position and better vibration isolation performance. Furthermore, an extended QZS isolator consisting of vertical spring with fixed stiffness and prestressed oblique springs is discussed to further improve stiffness characteristic. Better stiffness performance can be obtained when the prestressed oblique springs have softening stiffness and the exponent of the nonlinear stiffness is 2. Considering the existence of friction in practical application, the influence of friction on both static and dynamic characteristics is investigated. The analysis reveals that friction has little influence on its stiffness characteristic around the static equilibrium position and friction damping produced by friction affects the response amplitude and resonant frequency in dynamics.

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Vibhute, A. S., S. D. Bharti, M. K. Shrimali, and S. Vern. "Seismic Performance of Elastomeric and Sliding Friction Isolation System." Proceedings of the 12th Structural Engineering Convention, SEC 2022: Themes 1-2 1, no. 1 (December 19, 2022): 815–19. http://dx.doi.org/10.38208/acp.v1.588.

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The base isolation technique is widely used in the isolation of structures for providing efficient protection to structures concerning different loadings. This study aims to evaluate comparative performance and inelastic responses of the base-isolated structure for two types of isolation systems under the Far-field and Near-field earthquake. For this purpose, seismic response quantities like base shear, peak ?oor displacement, absolute acceleration, and isolator displacement for ten-story reinforced concrete building frame base isolated by lead rubber bearings (LRBs) are evaluated and compared with the seismic response of the same structure base isolated by Friction Pendulum Bearing Isolator. Nonlinear time history analysis is carried out to investigate the inelastic behavior of the base-isolated structure. The building frame was designed according to IS1893:2016 seismic code and IS 456:2000. To represent a wide range of assessments, a 10 storey building frame taking identical isolation parameters for elastomeric and sliding isolation system was analyzed in SAP 2000. It was observed that the responses of both the isolation system are nearly the same for all the three earthquakes.

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Zelleke, Daniel H., Said Elias, Vasant A. Matsagar, and Arvind K. Jain. "Supplemental dampers in base-isolated buildings to mitigate large isolator displacement under earthquake excitations." Bulletin of the New Zealand Society for Earthquake Engineering 48, no. 2 (June 30, 2015): 100–117. http://dx.doi.org/10.5459/bnzsee.48.2.100-117.

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The effect of viscous, viscoelastic, and friction supplemental dampers on the seismic response of base-isolated building supported by various isolation systems is investigated. Although base-isolated buildings have an advantage in reducing damage to the superstructure, the displacement at the isolation level is large, especially under near-fault ground motions. The influence of supplemental dampers in controlling the isolator displacement and other responses of base-isolated building is investigated using a multi-storey building frame. The coupled equations of motion are derived, solved and time history analysis is carried out on a building modeled with fifteen combinations of five isolation systems and three passive dampers. The seismic responses are compared with that of the fixed-base and base-isolated buildings. Based on the results, it is concluded that supplemental dampers are beneficial to control the large deformation at the isolator level. Parametric study is conducted and optimum ranges of damper parameters to achieve reduced isolator displacement without adverse effect on the other responses are determined. Further, it is concluded that the combination of the resilient-friction base isolator (R-FBI) and viscous damper is the most effective in reducing the bearing displacement without significant increase in superstructure forces.

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Lee, Donghun, and Michael C. Constantinou. "Quintuple Friction Pendulum Isolator: Behavior, Modeling, and Validation." Earthquake Spectra 32, no. 3 (August 2016): 1607–26. http://dx.doi.org/10.1193/040615eqs053m.

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This paper describes the behavior of the quintuple friction pendulum isolator, a spherical sliding isolator with six sliding surfaces, five effective pendula, and nine regimes of operation that allow for complex multi-stage adaptive behavior depending on the amplitude of displacement. An analytical model is presented that is capable of tracing the behavior of the isolator in two general configurations of geometric and frictional properties. This analytical model is useful for verifying computational models and in performing simplified calculations for analysis and design. A computational model that can be implemented in the program SAP2000 is also presented and verified by comparison to the analytical model. A model quintuple friction pendulum isolator has been tested and the results have been used to validate the analytical and computational models.

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Rawat, Aruna, Naseef Ummer, and Vasant Matsagar. "Performance of bi-directional elliptical rolling rods for base isolation of buildings under near-fault earthquakes." Advances in Structural Engineering 21, no. 5 (August 25, 2017): 675–93. http://dx.doi.org/10.1177/1369433217726896.

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Rolling base isolation system provides effective isolation to the structures from seismic base excitations by virtue of its low frictional resistance. Herein, dynamic analysis of flexible-shear type multi-storey building mounted on orthogonally placed elliptical rolling rod base isolation systems subjected to bi-directional components of near-fault earthquake ground motions is presented. The orthogonally placed rods would make it possible to resist the earthquake forces induced in the structure in both the horizontal directions. The curved surface of these elliptical rods has a self-restoring capability due to which the magnitude of peak isolator displacement and residual displacement is reduced. The roughness of the tempered curved surface of the rollers dissipates energy in motion due to frictional damping. The seismic performance of the multi-storey building mounted on the elliptical rolling rod base isolation system is compared with that mounted on the sliding pure-friction and cylindrical rolling rod systems. Parametric studies are conducted to examine the behavior of the building for different superstructure flexibilities, eccentricities of the elliptical rod, and coefficients of friction. It is concluded that the elliptical rolling rod base isolation system is effective in mitigation of damaging effects of the near-fault earthquake ground motions in the multi-storey buildings. Even under the near-fault earthquake ground motions, the base-isolated building mounted on the elliptical rolling rods shows considerable reduction in seismic response. The isolator displacement with the elliptical rolling rod base isolation system is less in comparison to the pure-friction and cylindrical rolling rod systems.

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Abed, Dana, Jafar Al Thawabteh, Yazan Alzubi, Jamal Assbeihat, and Eid Al-Sahawneh. "Influence of Earthquake Parameters on the Bi-directional Behavior of Base Isolation Systems." Civil Engineering Journal 8, no. 10 (October 1, 2022): 2038–52. http://dx.doi.org/10.28991/cej-2022-08-10-02.

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The introduction and development of the base isolation systems, especially the friction isolator device, were done recently to improve the capacity of adaptive behavior. The efficiency of multi-phase friction pendulums comes from their complexity, which helps reduce the structural responses and enhance structures' energy dissipation under lateral loads. Nevertheless, the influence of various earthquakes' properties on the behavior of base-isolation systems subjected to bi-directional seismic loading is still unclear. Hence, further research and studies regarding the behavior and capability of these systems under bi-directional loading are still necessary before incorporating this device in real-life practical applications. Therefore, this paper is intended to investigate the bi-directional behavior of the friction isolator subjected to various ground motion records. In order to do so, different versions of the friction pendulum system are selected and compared within the study context. Generally, the study's results have shown that the behavior of the friction isolator is highly dependent on low values of the PGA/PGV ratio. Besides, pulse-like earthquakes considerably impact the response of the isolator compared to non-pulse-like ones. Doi: 10.28991/CEJ-2022-08-10-02 Full Text: PDF

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Ozbulut, Osman E., and Stefan Hurlebaus. "A Comparative Study on the Seismic Performance of Superelastic-Friction Base Isolators against Near-Field Earthquakes." Earthquake Spectra 28, no. 3 (August 2012): 1147–63. http://dx.doi.org/10.1193/1.4000070.

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This paper presents a comparative seismic performance assessment of super-elastic-friction base isolator (S-FBI) systems in improving the response of bridges under near-field earthquakes. The S-FBI system consists of a steel-Teflon sliding bearing and a superelastic shape memory alloy (SMA) device. The other isolation systems considered here are lead rubber bearing (LRB), friction pendulum system (FPS), and resilient-friction base isolator (R-FBI). Each isolation system is designed to provide the same isolation period and characteristic strength. Nonlinear time-history analyses of an isolated bridge are performed to compare the performance of various isolation systems. The results indicate that the S-FBI system shows superior performance in reducing deck displacement response and effectively limits permanent bearing deformation, whereas residual deformations are present for the other isolation systems in some cases. It is also observed that the LRB system has the largest deck drifts while the FPS system and R-FBI system produce the smallest peak deck acceleration and base shear.

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Kamrava, Alireza. "Seismic Isolators and their Types." Current World Environment 10, Special-Issue1 (June 28, 2015): 27–32. http://dx.doi.org/10.12944/cwe.10.special-issue1.05.

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In this paper I would like to describe about what seismic isolation is., seismic isolators, their types ,how do they work? ,their advantage and disadvantage. In seismic isolator types you will read about Elastomeric bearings, Natural and Synthetic Rubber Bearings , Lead Rubber Bearings , Friction pendulum bearing, Supplymetal Damping Devices like Buckling Restrained Brace, Fluid Dampers, Visco-Elastic Dampers,Friction Dampers, Hysteretic Dampers(Yeilding Dampers).In advantage and disadvantage part you will read some tips about using seismic isolators. In conclusion you will read a review about seismic isolation and using seismic isolators.

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Cancellara, Donato, and Mario Pasquino. "A New Passive Seismic Control Device for Protection of Structures under Anomalous Seismic Events." Applied Mechanics and Materials 82 (July 2011): 651–56. http://dx.doi.org/10.4028/www.scientific.net/amm.82.651.

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In this paper, the possibility offered by the Base Isolation System, designed according to the strategy of limitation seismic force, in order to ensure a significant level of robustness to the isolated superstructure, has been analyzed. In according to the strategy of limitation seismic force, a new seismic isolator called HDHSI (High Damping Hybrid Seismic Isolator) is proposed, obtained by the assembly in series of a LRB (Lead Rubber Bearing) and a FS (Friction Slider) with high friction coefficient. The HDHSI device is in contrast to the R-FBI (Resilient-Friction Base Isolation) isolator and is the optimization of the EDF (Electricité De France) system. A modeling with HDHSI devise has been presented by using nonlinear finite elements NLlink (Nonlinear link) and nonlinear dynamic analysis for a SDOF system with harmonic force, in order to characterize the cycle-hysteretic behavior of the device for different levels of shear deformation, are performed. Nonlinear dynamic analysis for a RC structure, base isolated by the proposed devices, are performed. As seismic actions, have been adopted the following registrations: an anomalous earthquakes for intensity and in particular El Centro earthquake (N00W component, 1940) with different amplification factors; an anomalous earthquake for frequency content and in particular Erzincan earthquake (N90W component, 1992).

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Rezaei, Sima, and Gholamreza Ghodrati Amiri. "Effect of Supplemental Damping on the Seismic Performance of Triple Pendulum Bearing Isolators under Near-Fault Ground Motions ." Applied Mechanics and Materials 845 (July 2016): 240–45. http://dx.doi.org/10.4028/www.scientific.net/amm.845.240.

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The isolating system absorbs part of the earthquake energy before transferring it to the structure, by shifting the natural period of the isolated structure. This period shift results in a reduction in the inertial forces. It is clear that the effects of near-fault (NF) ground motions with large velocity pulses can bring the seismic isolation devices to critical working conditions. In this study, two three-dimensional RC buildings with the heights of 9.0m and 21.0m which are supported by Triple Friction Pendulum Bearing (TFPB) isolators are idealized. Various TFPB configurations are selected for isolation systems. There are also viscous dampers to limit the excess deformation of isolators. Nonlinear time history analyses were performed by using OpenSees to study the influence of supplemental dampers on structural responses such as isolator displacements and maximum drifts under ten near-fault ground motion records. The results show noticeable reduction in isolator displacement when using dampers. However, maximum drift rises considerablely. Moreover by increasing the period range or reducing the damping ratio of isolation system, maximum driftreduces but the displacement of isolator increases.

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Jangid, R. S., and P. Banerji. "Effects of Isolation Damping on Stochastic Response of Structures with Nonlinear Base Isolators." Earthquake Spectra 14, no. 1 (February 1998): 95–114. http://dx.doi.org/10.1193/1.1585990.

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Optimum isolator damping required to minimize absolute acceleration responses to stochastic ground motions in buildings with non-linear resilient-friction base isolation (R-FBI) devices is studied. Using a stochastic equivalent linearization technique, an analytical expression is developed for estimating optimum material damping values in an R-FBI system for a rigid superstructure. This optimum damping value depends on the effective time period and friction coefficient of the R-FBI system and the design earthquake intensity. The fixed base structural time period, damping, and the number of stories also affect the optimum isolator damping values, if the superstructure is flexible. However, the analytical expression mentioned above provides an upper-bound optimum isolator damping value for any superstructure with an R-FBI system subjected to a given earthquake intensity. Comparison of optimum damping values for a linear isolator and the R-FBI system, with identical lateral stiffness properties, illustrates the beneficial effect of sliding friction in reducing the optimum damping in the latter type of isolator, for a given earthquake intensity.

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Cancellara, Donato, Fabio de Angelis, and Mario Pasquino. "A Novel Seismic Base Isolation System Consisting of a Lead Rubber Bearing in Series with a Friction Slider. Part I: Nonlinear Modeling of the System." Applied Mechanics and Materials 256-259 (December 2012): 2185–92. http://dx.doi.org/10.4028/www.scientific.net/amm.256-259.2185.

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In this paper a new seismic base isolator, called High Damping Hybrid Seismic Isolator (HDHSI), is proposed. It is obtained by the assembly in series of a Lead Rubber Bearing (LRB) and a Friction Slider (FS) with a high friction coefficient. The HDHSI device is in contrast with the Resilient-Friction Base Isolator (R-FBI) with the aim of optimizing the Electricité De France (EDF) system. The mathematical model of a structure base isolated by a HDHSI system is analyzed with a two Degree of Freedom System (2-DOF) in which the superstructure is assimilated to a rigid body. Nonlinear finite elements are adopted for modeling the HDHSI device. A dynamic nonlinear analysis is performed and the hysteretic cycles are derived and evaluated for the single components and for the innovative HDHSI device.

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Kumar, Sooraj, and Ganesh Jaiswal. "Effectiveness of Different Base Isolation on Stepped Buildings." International Journal for Research in Applied Science and Engineering Technology 10, no. 7 (July 31, 2022): 4345–53. http://dx.doi.org/10.22214/ijraset.2022.45997.

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Abstract: Seismic isolation devices are commonly employed to protect structures from the impacts of severe ground motions. ETABS2016, a modelling and analysis programme, was used in this work to model and analyse the isolated stepped building. Rubber isolator link components were used as a single joint element to represent the rubber isolators between the ground and the superstructure. El-Centro seismic records were used to analyse the isolated building. The lateral inter-storey drifts, story displacement and peak absolute floor accelerations, of the isolated building were compared to those of the fixed-base structure. The current study aims to evaluate the effectiveness of several types of base isolation systems for seismic protection of 6-story stepped structures using Time history analysis. The isolation systems considered include, i) rubber isolators, ii) rubber isolators with energy dissipation systems, and iii) friction pendulum isolators.

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Sharma, Ajay, and SudhirKumar Soni. "Application of MR damper in Base-isolated Irregular Building with different variable sliding Isolators." Proceedings of the 12th Structural Engineering Convention, SEC 2022: Themes 1-2 1, no. 1 (December 19, 2022): 673–85. http://dx.doi.org/10.38208/acp.v1.568.

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Application of Electromagnetic induction (EMI) based passively controlled and some local response governed MR dampers in controlling the isolator displacement in base-isolated Irregular building have been studied and compared with the Lyapunov controller. The Irregular building is hybrid isolated with elastomeric rubber bearings and a variety of sliding isolators subjected to strong near field earthquakes acting bi-directionally in horizontal plane. The shear type base-isolated Irregular building is modelled as three-dimensional linear elastic structure having three degrees-of-freedom at each floor level. Time domain dynamic analysis of the building has been carried out using constant-average acceleration Newmark-Beta method and non-linear isolation forces has been taken care by fourth-order Runge-Kutta method. It is observed that the EMI based passive controller performs better than the Lyapunov controller though it reduces less base displacement but gives lower structural response among all the controllers. Local response governed Hyperbolic and Aly’s controller require only velocity and displacement at controller locations sound simpler in application as compared to Lyapunov controller especially to civil engineering structures like Irregular building. The Hyperbolic controller restrains base displacement comparable to the Lyapunov controller but gives less base shear and story drifts to Irregular building. Variable frequency pendulum isolator (VFPI) and variable curvature friction pendulum system (VCFPS) sliding isolators perform better with MR damper control in comparison to conventional friction pendulum system (FPS) in base–isolated Irregular building.

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Hui, An-Min, Ming Yan, Lei Zhang, Ying-Li Jin, Kaiping Wang, and Haichao Liu. "Shock Characteristics of the Opposed Disc Springs (ODS) Shock Isolator with Pretightening under Boundary Friction Condition." Shock and Vibration 2021 (April 22, 2021): 1–21. http://dx.doi.org/10.1155/2021/5510200.

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In this study, to solve the problems of shock environment and shock isolation, about which there is still a lack of reasonable description, an isokinetic shock distinguishing method (ISDM), which can quantitatively distinguish between shock and forced vibration state, is presented. And the shock isolation performance of an opposed disc springs (ODS) shock isolator with pretightening under boundary friction condition is investigated. The static and dynamic stiffness properties of the ODS shock isolator are discussed. Relying on ISDM, a shock dynamic model of the ODS shock isolator with pretightening under boundary friction condition is established. The average method is adopted to solve the model theoretically. The shock acceleration ratio (SAR), shock displacement ratio (SDR), and relative displacement ratio (RDR) of the model are calculated using the numerical method and verified by experiments. Both numerical and experimental results show that ISDM is effective. And the effects on isolation efficiency of the number of disc springs, additional supporting force, pretightening force, load, and the shock velocity constant of the ODS shock isolator are discussed, which provide guidelines for its further practical application.

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Cancellara, Donato, Fabio de Angelis, and Mario Pasquino. "A Novel Seismic Base Isolation System Consisting of a Lead Rubber Bearing in Series with a Friction Slider. Part II: Application to a Multi-Storey RC Building and Comparison with Traditional Systems." Applied Mechanics and Materials 256-259 (December 2012): 2174–84. http://dx.doi.org/10.4028/www.scientific.net/amm.256-259.2174.

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In a parallel paper a new High Damping Hybrid Seismic Isolator (HDHSI) has been proposed and obtained by the assembly in series of a Lead Rubber Bearing (LRB) and a Friction Slider (FS) characterized by a high friction coefficient. In the present paper, within the context of seismic base isolation techniques for the earthquake resistance of Reinforced Concrete (RC) buildings, a multi-storey RC building is analyzed as base isolated by the seismic isolator HDHSI (High Damping Hybrid Seismic Isolator). The seismic response of this base isolated RC building is compared with the seismic response of the same structure isolated by a LRB (Lead Rubber Bearing) isolator. The analysis is developed by considering different seismic events in terms of intensity and in terms of frequency content with regard to a supervening collapse. The purpose of this comparative analysis is to highlight the features offered by the HDHSI system compared to the LRB system in the seismic protection of structures. Accordingly, a nonlinear dynamic analysis is performed for a RC structure base isolated by means of the proposed device. In the analysis anomalous seismic events are considered. They are the El Centro earthquake (N00W component, 1940) which is characterized by high intensity and the Erzincan earthquake (N90W component, 1992) which is characterized by anomalous frequency content. The comparison between the two base isolation systems is presented by analyzing the time history of the shear force and the time history of the displacement at the base of the superstructure. The benefits of the HDHSI system in conferring protection to the structure are shown to be significant even under extreme seismic events.

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Tsipianitis, Alexandros, Andreas Spachis, and Yiannis Tsompanakis. "Combined Optimization of Friction-Based Isolators in Liquid Storage Tanks." Applied Sciences 12, no. 19 (September 30, 2022): 9879. http://dx.doi.org/10.3390/app12199879.

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Large-scale tanks are widely used for storing chemicals and fuels. Their failure due to natural (e.g., earthquakes) and/or man-made hazards can lead to disastrous consequences. Nonetheless, they are often constructed in seismic-prone regions. For this reason, base isolation is often used for the seismic protection of large tanks, aiming to “decouple” the superstructure from the imposed ground motions. In this study, a combined optimization formulation is presented in order to further improve the seismic response of a base-isolated tank. The main aim is to optimize both the critical design parameters and the placement of the minimum number of isolators at the base of the tank. In particular, a Cuckoo Search (CS) optimizer is used to optimize the dynamic performance of liquid storage tanks, isolated either via single friction pendulum bearings (SFPB) or triple friction pendulum bearings (TFPB). The main objective is to minimize the eccentricity between the center of mass and the center of rigidity of the isolation system, while appropriate constraints are also imposed. Several cases are examined, while the results are compared with respect to isolator displacement fragility curves, as well as the reduced accelerations at the base of the tank. According to the findings of this study, the tank industry can significantly benefit from the proposed approach, as a more cost-efficient design of the base-isolation system of large-scale tanks can be achieved, i.e., using fewer isolators with optimal key parameters.

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Liu, Lin, Xuan Min Li, and Wei Tian. "Seismic Isolation Retrofit of an Office Building Using Friction Pendulum System." Applied Mechanics and Materials 578-579 (July 2014): 1361–65. http://dx.doi.org/10.4028/www.scientific.net/amm.578-579.1361.

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Friction Pendulum Systems have been used as base isolation systems for both new construction and retrofit around the world. This paper presented its implementation in an office building located in Shanghai. To evaluate its impact on seismic performance of the retrofitted structure, models are needed to capture the intricate nonlinear behavior of both structural components and isolator elements. Nonlinear time history analysis of the building for the original and retrofitted cases was conducted to assess the efficiency of the isolation system at the high earthquake level. The numerical results indicate that the retrofitted structure experiences significantly less damage and less deformation due to the shake isolation and energy dissipation through the isolators.

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Li, Ming, Wei Cheng, and Ruili Xie. "Design and experiments of a quasi–zero-stiffness isolator with a noncircular cam-based negative-stiffness mechanism." Journal of Vibration and Control 26, no. 21-22 (February 19, 2020): 1935–47. http://dx.doi.org/10.1177/1077546320908689.

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This article presents a quasi–zero-stiffness isolator with a cam-based negative-stiffness mechanism, where the cam has a user-defined noncircular profile to generate negative stiffness to counterbalance the positive stiffness of the vertical spring and yield the quasi–zero-stiffness characteristic around the equilibrium position. Unlike previous studies, the proposed quasi–zero-stiffness isolator has the preferable feature that the desired cubic restoring force can be directly obtained through the well-designed profile of the cam in the negative-stiffness mechanism with the friction considered during the model design, rather than through the Taylor expansion and friction-ignoring assumption, which can avoid the approximation error between the theoretical design and the specific realization. The pure-cubic nonlinear differential equation of motion of the quasi–zero-stiffness isolator is derived and solved with the harmonic balance method, followed by the discussion of the relevant dynamic characteristics. Experimental studies are carried out based on the physical prototype of the quasi–zero-stiffness isolator. The results show that the quasi–zero-stiffness isolator can greatly extend the isolation frequency bandwidth and has a much lower resonance peak. In the low-frequency band, the quasi–zero-stiffness isolator greatly outperforms the corresponding linear system but is equivalent or even inferior in the high-frequency range with the increase of excitation force.

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Mostaghel, N., and M. Khodaverdian. "Dynamics of resilient-friction base isolator (R-FBI)." Earthquake Engineering & Structural Dynamics 15, no. 3 (April 1987): 379–90. http://dx.doi.org/10.1002/eqe.4290150307.

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Sabiha, Hamouche, Bennacer Lyacine, and Nassim Kernou. "Comparative Study of the Non-Linear Dynamic Behaviour of Different Seismic Isolation Systems." Advanced Engineering Forum 48 (January 10, 2023): 17–29. http://dx.doi.org/10.4028/p-97i58z.

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To mitigate the effect of earthquake on the structure, the base isolation technique is the best alternative as a seismic protection system. In this research, a two-degree-of-freedom (2DOF) equivalent model is modelled based on a real eight-level reinforced concrete structure damaged by the Boumerdes earthquake in 2003 is presented. The basic isolation systems considered are four models namely: the first system is a high damping isolator (HDBR), the second system is the friction pendulum isolator (FPS). The third model of the base isolation system is a non-linear model with two horizontal and rotational stiffness springs (SHRS), and finally the last model presents a bilinear spring (SB). The isolators are designed according to the UBC-97 code. Earthquake recordings from Dar-El-Beida of the 2003 Boumerdes earthquake were used as seismic load. A dynamic analysis of the comparative temporal responses of the structure was performed by comparing its dynamic behaviour with that of the fixed base structure. The results obtained reveal a reduction in base shear, stage drift and stage acceleration and an increase in displacement and time period for the structure isolated at the base. The results are presented in tables and graphs.

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Sharma, Ajay, and Sudhir Soni. "Seismic Performance of Irregular Building with different Variable sliding isolators and Semi active Dampers." Proceedings of the 12th Structural Engineering Convention, SEC 2022: Themes 1-2 1, no. 1 (December 19, 2022): 659–71. http://dx.doi.org/10.38208/acp.v1.567.

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The comparative performances of semiactive friction and stiffness dampers with different control laws in the base-isolated Irregular building subjected to bi-directionally acting strong earthquakes have been studied. The Irregular building is hybridly isolated with rubber bearings and friction pendulum system (FPS) or variable frequency pendulum isolator (VFPI) or variable curvature friction pendulum system (VCFPS). The shear type base-isolated Irregular building is modeled as three-dimensional linear elastic structure having three degrees-of-freedom at each floor level. Time domain dynamic analysis of the building has been carried out with the help of constant average acceleration Newmark-Beta method and non-linear isolation forces has been taken care by fourth-order Runge-Kutta method. The effects of variation of characteristic properties of semiactive dampers on their hysteresis loops and on the structural response of Irregular building is studied through parametric study. Comparative performances of different semiactive dampers with sliding isolation systems for seismic control of Irregular building have been observed through time history plots and peak response performance indices. It has been found that semiactive electromagnetic friction damper work efficiently with VFPI and VCFPS in comparison FPS for the Irregular building for near field earthquakes as it not only reduces base displacement at lower control force but also give lower base shear and story drift in base-isolated Irregular building. The control laws based on modulated homogeneous friction control semiactive friction dampers better than the predictive control law.

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Shih, Ming-Hsiang, Wen-Pei Sung, and Chia-Yu Ho. "Experimental Validation of Numerical Model for Bi-Tilt-Isolator." Shock and Vibration 2018 (2018): 1–12. http://dx.doi.org/10.1155/2018/7163516.

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Bi-Tilt Isolator (BTI) is composed of bi-tilt beveled substrate and slider. The advantages of BTI are that the maximum upload seismic force of structure can be easily controlled and displacement of isolation layer will be reduced. Sliding force, friction force, and impulse force are caused in the slanting process of BTI, nonlinear behavior. A nonlinear mathematical model is derived based on the sliding upwards, sliding downwards, and transition stages. Then, BTI element of nonlinear analysis program, GENDYN, is developed by the fourth-order Runge-Kutta method, the discretized ordinary differential equation for three movement stages of BTI. Then, test set-up of superstructure installed with BTI is tested and recorded the real displacement and acceleration responses under conditions of full lubrication, mild lubrication, and without lubrication between interface of bi-tilt beveled substrate and slider with three various initial displacements. The comparison of simulation results and test results shows the following: (1) root mean square error is below 1.35% for WD40 sprayed, 0.47% for WD40 whipped, and 0.54% for without lubrication, respectively; (2) the maximum root mean square error for simulating with cubic polynomial function of friction is much less than those of constant friction except conditions of full lubrication, which are not affected by kinetic friction force; (3) application of cubic polynomial function for simulating friction of BTI with three different lubricated conditions can perform very fine simulation results, compared with the test results. This proposed mathematical model and BTI element of GENDYN program, using cubic polynomial function of friction, perform fine simulation capability to assess nonlinear isolation effect of structure installed with BTI.

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Haeri, A. H., K. Badamchi, and H. Tajmir Riahi. "Proposing a new hybrid friction–yielding–elastomeric bearing." Journal of Vibration and Control 25, no. 9 (February 20, 2019): 1558–71. http://dx.doi.org/10.1177/1077546319829535.

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A new hybrid isolator consisting of elastomeric bearing, sliding parts and yielding dampers named friction–yielding–elastomeric bearing (FYEB) is proposed. In this hybrid isolator, the friction–yielding part has an energy absorption feature, where the rubber pad has re-centering and vertical bearing capacity. For this purpose, an X-shaped metal damper with different number and thickness, and sliding surfaces with different friction coefficients is applied and the effect of vertical load variations on the results is assessed. Using the hysteresis force-displacement diagrams of different FYEB and lead rubber bearing (LRB) with the same dimensions at shear strains of 50, 100, and 150%, effective horizontal stiffness, energy dissipation, equivalent viscous damping, and lateral force at each loading cycle are assessed and compared. It can be concluded that the proposed isolator has a more suitable and stable performance at all shear strains than LRB. In addition, by changing FYEB parameters, a wide range of performance can be achieved.

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Xu, Yanqing, Tong Guo, and Ping Yan. "Design optimization of triple friction pendulums for base-isolated high-rise buildings." Advances in Structural Engineering 22, no. 13 (May 26, 2019): 2727–40. http://dx.doi.org/10.1177/1369433219849840.

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The triple friction pendulum bearing, as a novel seismic isolator, has received much attention due to its notable advantages such as variable stiffness and damping; however, existing investigations and applications are mainly for low-rise or medium-rise buildings. In order to determine optimal design parameters of triple friction pendulum bearings for high-rise buildings, equations of motion for an isolated high-rise building are derived, and an evaluation function is developed to indicate the isolation effect with different pendulum parameters. In the optimization analysis, seven ground motions are scaled to three levels (corresponding to the service level, the design basis, and the maximum considered earthquakes, respectively) and the genetic algorithm is applied to determine the optimal pendulum parameters. The optimization results are compared with those obtained by the single-degree-of-freedom model, where significant difference is observed, showing the necessity of the presented study. Using the optimal parameters of triple friction pendulum bearings, seismic responses of the isolated building are analyzed and compared with those of the building isolated using the single friction pendulum bearings and the base-fixed building, where it is observed that the triple friction pendulum bearing is more effective and reliable in reducing base shear, floor acceleration, and story drifts.

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29

Constantinescu, Silviu Alexandru, and Ionuț Radu Răcănel. "Seismic Isolation of Bridges Using the Principle of Electromagnetic Attraction and Repulsion." Romanian Journal of Transport Infrastructure 6, no. 1 (July 1, 2017): 1–14. http://dx.doi.org/10.1515/rjti-2017-0050.

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Abstract This paper presents a new type of seismic isolator that uses the principle of electromagnetic attraction and repulsion, to control the friction force between two electromagnets during earthquakes. The two electromagnets are used in conjunction with a secondary high friction dissipating and damping mechanism composed from a 10mm thick neoprene ring layer and two steel surfaces coated with Si3N4 that are used to dissipate the kinetic energy in the bridge deck at some maximum ground accelerations. The isolator utilizes tri-axial accelerometers embedded in the abutments, high current rechargeable batteries and an automated controlling unit. The presented isolator was developed specifically for a concrete bridge deck with a span of 36 meters and simple supported on two abutments, using time history electromagnetic and structural analyses. The paper presents the advantages of using this active seismic isolation system, compared to classical passive devices and the important results obtained in terms of decreasing internal forces on the substructure elements cross sections together with the reduction of relative displacements between the two electromagnets.

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Shang, Jiying, Ping Tan, Yafei Zhang, Jianping Han, and Jiajun Qin. "Experimental and analytical investigation of variable friction pendulum isolator." Engineering Structures 243 (September 2021): 112575. http://dx.doi.org/10.1016/j.engstruct.2021.112575.

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31

Shih, Ming-Hsiang, and Wen-Pei Sung. "Developing Smart Measurement Device to Measure Kinetic Friction Coefficients of Bi-Tilt Isolator." Advances in Civil Engineering 2019 (January 2, 2019): 1–12. http://dx.doi.org/10.1155/2019/4392506.

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A sliding vibration isolation system, affected by a kinetic friction force, provides a flexible or energy dissipation system for a structure. The kinetic friction coefficient of the contact surfaces between the moving parts changes with the relative moving velocity of the two contact surfaces. In this study, a smart measuring device is proposed to measure the kinetic friction coefficients of materials. The Arduino boards Arduino Nano, Arduino MPU-9250, and Arduino SD modules were combined to create this proposed smart device and mounted on three aluminum extrusions constructed as a horizontal platform. Then, varying amounts of steel gaskets were applied to adjust the various slopes for sliding tests. The time history of the acceleration and displacement responses of test object movements in the sliding process were respectively, recorded and detected by this proposed smart measuring device and the digital image correlation method (DIC). Statistical analyses of all test responses were used to derive the relationship of velocity to kinetic friction coefficient. Test and analysis results showed that (1) the relationship of velocity to kinetic friction coefficient for the conditions of mild lubrication and no lubrication displayed a trend of first decreasing and then increasing with increasing speed, respectively and (2) the relationship of velocity to kinetic friction coefficient for the condition of full lubrication revealed that the kinetic friction coefficient decreased with increasing speed. Test results demonstrated that this proposed smart measurement device, which is low in price and easy to assemble, can easily measure the kinetic friction coefficient of a material under various lubrication conditions.

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Çakat, Gözde, and Zeynep Fırat Alemdar. "Seismic base isolation of a typical hospital structure with a friction pendulum isolator." Journal of Structural Engineering & Applied Mechanics 2, no. 1 (March 30, 2019): 1–11. http://dx.doi.org/10.31462/jseam.2019.01001011.

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33

Krishnamoorthy, Agrahara. "Seismic Isolation of Bridges Using Variable Frequency and Variable Friction Pendulum Isolator System." Structural Engineering International 20, no. 2 (May 2010): 178–84. http://dx.doi.org/10.2749/101686610791283632.

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34

Rajput, Gautam, and Vinayak Mishra. "Performance of RC Building with Different base Isolators." International Journal for Research in Applied Science and Engineering Technology 10, no. 8 (August 31, 2022): 1265–69. http://dx.doi.org/10.22214/ijraset.2022.46404.

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Abstract: The paper evaluates the application of base isolation methods based on the location of site. Building various sorts of structures while assuring their safety, serviceability, and durability is the focus of civil engineering. Seismic activity has severe impact on the structures' serviceability and safety. The type of building, the type of soil, the technology utilized for seismic resistant, and the location of the building, all the effects how much damage an earthquake may cause to structures. Because an earthquake alters the motion of the ground, which causes foundation failure, the effects of an earthquake are primarily dependent on the type of soil used for building foundations. Therefore, it is crucial to study how different types of soil behave during occurrence of earthquakes. A base isolation technique is one of the methods utilized in construction that can resist earthquakes. It enhances a building's structural performance when it is subjected to lateral stresses. This paper studies the effect of an earthquake response of isolated buildings and provides analysis of the base isolation on the structure's nature as well as a discussion of various isolator types. It compares the performance of two types of isolators: Lead Rubber Bearing (LRB) and Friction Pendulum Bearing (FPB). G+12 R.C structure is taken in this study & Time History analysis is performed with ETABS software. Time Period and Story Stiffness are compared for the building with the base isolator against the building with the fixed base. In comparison with a fixed base building, parameters are changed in each direction due to the presence of an isolator. The analysis examines the characteristics and the effects of base isolation on structures with the Bhuj earthquake.

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35

Xia, Dong Zhou. "Study on Seismic Performance of Symmetrical Steel Framed Building that with and without ERB and FPS Isolators." Applied Mechanics and Materials 204-208 (October 2012): 2634–40. http://dx.doi.org/10.4028/www.scientific.net/amm.204-208.2634.

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As is known, base isolation can reduce earthquake energy that transferred from the ground motion to the structure by buffering it with a bearing layer at the foundation which has relatively low horizontal stiffness. The paper investigates the time history records of a two storied symmetrical steel framed isolated building with Elastomeric Rubber Bearing and Friction Pendulum Systems that under the Northridge earthquake, and the isolator parameters are calculated using the design guidelines of International Building Code (IBC2000) within the spirit of IS 1893–2002(7). And then, contrasting of the roof’s displacements, accelerations and base shear values of the steel framed building with and without isolators, and which studied from the Non-linear time history analysis using structural analysis software SAP2000. The results show that base isolation will provide a substitute technology for the conventional, fixed-base design of structures and cost-effective for new buildings in high seismic regions.

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36

Jampole, Ezra, Gregory Deierlein, Eduardo Miranda, Benjamin Fell, Scott Swensen, and Cristian Acevedo. "Full-Scale Dynamic Testing of a Sliding Seismically Isolated Unibody House." Earthquake Spectra 32, no. 4 (November 2016): 2245–70. http://dx.doi.org/10.1193/010616eqs003m.

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Shaking table tests were conducted on a new low cost sliding seismic isolation system aimed at significantly improving the seismic performance of low-rise lightweight residential construction. A two-story, full-scale seismically isolated wood frame house was tested dynamically under multiple ground motions on a shake table. Two different sliding isolation bearings were evaluated, one with flat and another with concave sliding surfaces, both with high-density polyethylene sliders on galvanized steel surfaces with a coefficient of friction of approximately 0.18. Each isolation system was subjected to seven severe recorded earthquake ground motions, which produced peak isolator displacements of up to 41 cm. The maximum induced inertial shear force on the superstructure was on the order of 0.4 g, yet the house remained practically damage-free with story drift ratios less than 0.1%. The study successfully (1) provides a proof-of-concept for design, construction, and behavior of a light-frame house with low-cost high friction sliding seismic isolation, (2) confirms several design assumptions regarding isolation behavior and maximum isolation displacement, and (3) provides data to validate computational models and develop design guidelines for the isolated superstructure.

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37

Vo, Ngoc Yen Phuong, and Thanh Danh Le. "Dynamic Analysis of Quasi-Zero Stiffness Pneumatic Vibration Isolator." Applied Sciences 12, no. 5 (February 24, 2022): 2378. http://dx.doi.org/10.3390/app12052378.

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This paper focuses on analyzing the dynamic response of an innovated quasi-zero stiffness pneumatic vibration isolator (QZSPVI) using two mechanisms, including wedge and semicircle cam. Different from other studies relating quasi-zero stiffness isolation system, the pneumatic cylinder in this paper works as an air spring in order to easily adjust the dynamic stiffness of the proposed system according to the change of the isolated load through regulating the pressure. Firstly, the dynamic stiffness of the QZSPVI will be analyzed. Then, the condition for which the minimum dynamic stiffness is quasi-zero around the equilibrium position is also determined. The fundamental resonance response of the QZSPVI subjected to the externally harmonic force is analyzed through multi-scale method and the numerical simulations are verified. Secondly, due to exiting relative sliding frictional phenomenon between the cylinder and piston, instead of an experiment, another key content of this work is to identify the friction force model of the cylinder through virtual prototyping model. From this identified result, the complex dynamic response of the QZSPVI and coexistence of multiple solutions will be discovered by realizing the direct integration of the original dynamic equation through using the 5th-order Runge–Kutta algorithm. The analysis and simulation results clearly show the advantages of the proposed model against the equivalent pneumatic vibration isolator (EPVI), which only employs the wedge mechanism. This research will offer a useful insight into design and QZSPVI in practice.

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38

Sodha, A. H., D. P. Soni, M. K. Desai, and S. Kumar. "Behavior of Quintuple Friction Pendulum System Under Near-Fault Earthquakes." Journal of Earthquake and Tsunami 11, no. 05 (December 2017): 1750017. http://dx.doi.org/10.1142/s1793431117500178.

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The Quintuple Friction Pendulum (QTFP) system is a new generation sliding isolation having six spherical sliding surfaces with five effective pendula. Due to multiple sliding surfaces, QTFP system shows highly adaptive behavior under different hazard level of earthquakes, despite being a passive system. The paper describes mathematical model and seismic response of QTFP system under 60 earthquake records consisting of service level, design basis and maximum considered earthquakes. To study the effect of directivity focusing and fling step, additional 15 records consist of far-field, near-fault with forward directivity and fling step effect are also considered. Three types of effective period and effective damping in combination with two different displacement capacities of QTFP bearing resulting in six isolator designs are considered. The seismic demand parameters like base shear, top floor absolute acceleration and isolator displacement have been studied. It is found that the QTFP bearing stiffens at low input, softens with increasing input, and then stiffens again at higher levels of input. Thus, it shows highly adaptive behavior under different hazard levels of earthquake. Further, due to forward and backward momentum conveyed by the directivity pulse, near-fault directivity effect imposes higher demand compared to fling step containing only forward momentum.

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39

Ao, Hong Rui, Hong Yuan Jiang, and A. M. Ulanov. "Estimation of the Fatigue Lifetime of Metal Rubber Isolator with Dry Friction Damping." Key Engineering Materials 326-328 (December 2006): 949–52. http://dx.doi.org/10.4028/www.scientific.net/kem.326-328.949.

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Metal rubber (MR) sleeve isolators have been widely applied in aerospace industry. An experimental investigation into its fatigue lifetime was conducted. The results indicate that its performance is determined by the following factors: the relative deformation of MR sleeve elements, the preloading of sleeve elements, friction coefficient of metal wires and vibration amplitude. It is concluded that solid lubricates can increase the lifetime of MR isolator greatly but lower its ability to dissipate vibrating energy.

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40

Papadopoulos, I. C., and I. A. Tegos. "An Innovative Friction-Based Seismic Isolator Utilizing Bridge Approach Embankments." Indian Geotechnical Journal 44, no. 2 (December 6, 2013): 196–204. http://dx.doi.org/10.1007/s40098-013-0090-2.

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41

Kim, Sung-Wan, Bub-Gyu Jeon, Da-Woon Yun, Woo-Young Jung, and Bu-Seog Ju. "Seismic Experimental Assessment of Remote Terminal Unit System with Friction Pendulum under Triaxial Shake Table Tests." Metals 11, no. 9 (September 9, 2021): 1428. http://dx.doi.org/10.3390/met11091428.

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In recent years, earthquakes have caused more damage to nonstructural components, such as mechanical and electrical equipment and piping systems, than to structural components. In particular, among the nonstructural components, the electrical cabinet is an essential piece of equipment used to maintain the functionality of critical facilities such as nuclear and non-nuclear power plants. Therefore, damage to the electrical cabinet associated with the safety of the facility can lead to severe accidents related to loss-of-life and property damage. Consequently, the electrical cabinet system must be protected against strong ground motion. This paper presents an exploratory study of dynamic characteristics of seismically isolated remote terminal unit (RTU) cabinet system subjected to tri-axial shaking table, and also the shaking table test of the non-seismically isolated cabinet system was conducted to compare the vibration characteristics with the cabinet system installed with friction pendulum isolator device. In addition, for the shaking table test, two recorded earthquakes obtained from Korea and artificial earthquakes based on the common application of building seismic-resistant design standards as an input ground motions were applied. The experimental assessment showed that the various damage modes such as door opening, the fall of the wire mold, and damage to door lock occurred in the RTU panel fixed on the concrete foundation by a set anchor, but the damage occurred only at the seismic isolator in the seismically isolated RTU panel system. Furthermore, it was considered that the application of the seismic isolator can effectively mitigate the impact and amplification of seismic force to the RTU panel system during and after strong ground motions in this study.

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42

Zheng, En Lai, Fang Jia, Zhi Sheng Zhang, and Jin Fei Shi. "Modeling and Simulation of Nonlinear Combination Disc-Spring Vibration Isolator for High-Speed Press." Advanced Materials Research 211-212 (February 2011): 40–47. http://dx.doi.org/10.4028/www.scientific.net/amr.211-212.40.

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With its variable stiffness, capability to provide friction damping by itself, and space-based adaptive performance, the disc spring, by replacing the cylindrical helical spring extensively, has found wide application in fields like aerospace, metallurgy, architecture, machinery and so on. For the nonlinear combination disc-spring vibration isolator, the mathematical model is established in this study on the basis of classical disc spring theories. The simulation results of the combination vibration isolator under simple harmonic excitation and the effects of damping ratio and different types of load on the vibration isolator are explored in depth, the findings of which help to lay a solid foundation for parameterization and serialization of the nonlinear combination disc-spring vibration isolator.

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43

Rajput, Gautam, and Vinayak Mishra. "Seismic Performance of Multi Story Building with Different Base Isolators." International Journal for Research in Applied Science and Engineering Technology 10, no. 8 (August 31, 2022): 1259–64. http://dx.doi.org/10.22214/ijraset.2022.46403.

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Abstract: Earthquakes are one of nature's most dangerous hazards; throughout history, they have resulted in substantial loss of life and serious property damage, particularly to man-made structures. Seismic activity of large magnitude is a major source of risk for all types of constructions. We apply unique methodologies based on performance-based seismic design to protect structures from earthquakes. One way for reducing the influence of large-scale vibration created during an earthquake is the base isolation method. Seismic isolation can be used to give an efficient solution for a variety of seismic design difficulties according to well-established practices that have been examined by several researchers. It compares the performance of two types of isolators: Lead Rubber Bearing (LRB) and Friction Pendulum Bearing (FPB). G+12 R.C structure is taken in this study & Time History analysis is performed with ETABS software. Story drift and Story force are compared for the building with the base isolator against the building with the fixed base. In comparison with a fixed base building, parameters are changed in each direction due to the presence of an isolator. The analysis examines the characteristics and the effects of base isolation on structures with the Uttarkashi earthquake.

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44

Zelleke, Daniel H., Sandip K. Saha, and Vasant A. Matsagar. "Multihazard Response Control of Base-Isolated Buildings under Bidirectional Dynamic Excitation." Shock and Vibration 2020 (December 19, 2020): 1–24. http://dx.doi.org/10.1155/2020/8830460.

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The issues of safety and posthazard functionality of structures under multihazard scenarios are some of the significant challenges in the current dynamic and rapidly growing urban environment. In this paper, multistory base-isolated buildings are investigated under the independent multihazard scenario of earthquake and blast-induced ground motion (BIGM). Multistory building models equipped with five different types of isolation systems, namely, the laminated rubber bearing (LRB), lead-rubber bearing (N-Z system), pure friction (PF) system, friction pendulum system (FPS), and resilient-friction base isolator (R-FBI) are assessed under bidirectional multihazard excitations. The suitability of the isolation systems and their key parameters in protecting multistory buildings is evaluated. Furthermore, the influence of the superstructure characteristics, such as the superstructure damping and the number of stories, is also assessed. The effect of bidirectional hazards on fixed-base buildings is also presented for comparison. The key response quantities of base-isolated buildings are presented and compared for different isolation systems. Parametric investigations are also conducted, and the trends of the response quantities are presented to study the influence of important parameters of isolation systems in protecting the buildings under the multihazard scenario of earthquake and BIGM. The results of the investigation show that the behaviors of the buildings equipped with various isolation systems are different for the two hazards. Moreover, the influences of the key parameters of the isolation systems are found to be different for various hazards. Therefore, the selection of design parameters of isolation systems shall be made with due consideration of the influence of multiple hazards. Additionally, the influence of the properties of the superstructure, such as the number of stories and the damping of the superstructure, on the behavior of the base-isolated buildings under the multihazard loading, is presented.

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45

SHINTANI, Masanori, Naoya TAGUCHI, and Yuichi HATTORI. "106 Experimental Verification of the Seismic Isolator by Using Friction Force." Proceedings of the Dynamics & Design Conference 2007 (2007): _106–1_—_106–6_. http://dx.doi.org/10.1299/jsmedmc.2007._106-1_.

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46

Vasanwala, Sandip A., Ankit H. Sodha, and Devesh P. Soni. "Evaluation of linear visco-elastic model of quintuple friction pendulum isolator." International Journal of Structural Engineering 11, no. 1 (2021): 19. http://dx.doi.org/10.1504/ijstructe.2021.10033855.

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47

Sodha, Ankit H., Devesh P. Soni, and Sandip A. Vasanwala. "Evaluation of linear visco-elastic model of quintuple friction pendulum isolator." International Journal of Structural Engineering 11, no. 1 (2021): 19. http://dx.doi.org/10.1504/ijstructe.2021.112090.

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48

Ihira, Naoki, and Masashi Yasuda. "Development of Low Friction Type Horizontal Seismic Isolator Using Pneumatic Levitation." Proceedings of the Dynamics & Design Conference 2016 (2016): 214. http://dx.doi.org/10.1299/jsmedmc.2016.214.

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49

Yang, Qiao, Hai Bo Chen, and Yong Yan Wang. "Statistical Energy Analysis of Fractional Derivative Model-Based Rubber Vibration Isolating System." Applied Mechanics and Materials 437 (October 2013): 114–19. http://dx.doi.org/10.4028/www.scientific.net/amm.437.114.

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The fractional derivative model and Coulomb friction model are introduced to describe the nonlinear characteristics of rubber isolators. Then the non-conservative coupling theory is used to calculate the statistical energy analysis (SEA) parameters of a typical non-conservative coupling system formed by two square plates and a rubber isolator. Numerical results are compared with those obtained by using the traditional viscous damping model, which shows that higher accuracy can be obtained by using the fractional derivative model in high-frequency band.

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50

Barrera-Vargas, Christian A., Iván M. Díaz, José M. Soria, and Jaime H. García-Palacios. "Enhancing Friction Pendulum Isolation Systems Using Passive and Semi-Active Dampers." Applied Sciences 10, no. 16 (August 13, 2020): 5621. http://dx.doi.org/10.3390/app10165621.

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Friction pendulum systems (FPSs) are a common solution for isolating civil engineering structures under ground movements. The result is a base-isolated structure in which the base exhibits low shear stiffness in such a way that the input energy of the earthquake is concentrated and dissipated into it, leaving the superstructure free of damage. As a consequence, large displacements of the FPS may be demanded depending on the earthquake intensity and the fundamental period of the FPS. To accommodate these displacements, large-size isolators with high friction coefficients are usually required. However, the FPS will then exhibit poor re-centering capacity and the risk of future shocks will increase due to previous residual displacements, especially for low-intensity earthquakes. An alternative solution is to include a semi-active damper to the FPS, keeping the friction coefficient low and achieving both, limited base displacement under high-intensity earthquakes and good re-centering capacity under low-intensity ones. Thus, this work presents a design methodology for base isolators formed by an FPS with a damper added. The design methodology is applied to an FPS with a passive damper and to an FPS with a semi-active damper. Two ON-OFF control strategies are studied: (i) a fairly simple phase control, and (ii), a mechanical energy-predictive based algorithm. The advantages of semi-active FPSs with low friction coefficients with respect to FPS with high friction coefficients are demonstrated. The results with the designed semi-active FPS are compared with the single FPS and the FPS with a passive damper. Finally, the use of semi-active FPS allows us to enhance the FPS performance as the isolator size can be reduced while keeping the capacity to cope with low and high-intensity earthquakes without residual displacements.

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Journal articles on the topic 'Friction isolator'

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