Journal articles: 'Vibration period'

1

Ryazancev, V., M. Gerasimov, and Y. Brazhnik. "REDUCTION OF DIFFERENTLY DIRECTIONAL VIBRATIONS TO ASYMMETRICAL BY CHANGING THE RATIO OF VALUES COMPOSING THE DRIVING FORCE." Bulletin of Belgorod State Technological University named after. V. G. Shukhov 6, no. 5 (May 18, 2021): 87–94. http://dx.doi.org/10.34031/2071-7318-2021-6-5-87-94.

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Vibrating machines play a primary role in the implementation of programs in the construction and road construction kit. The improvement of vibration machines allows to significantly increase the speed of construction and road construction work. The main working unit of a vibrating machine is a vibrating device or vibrator. Currently, in the industry, vibration devices are used with circular or directional, along a certain straight line of vibrations. Further improvement of vibrating machines is carried out in the direction of creating vibration devices with asymmetric vibrations. At present, there are practically no vibrating machines with asymmetric vibrations. These machines allow to distinguish between the "working" process phase and the "idle" phase within each oscillation period. Moreover, the value of the driving force in the phase of performing useful work is several times higher than the value of the driving force in the direction of idling. Therefore, much less work is spent on idling. This allows to get rid of massive elements - overloads that extinguish the magnitude of the driving force in the direction of idling. Therefore, the urgency is to develop a method for converting existing machines with directional vibrations into asymmetric ones, with a given coefficient of asymmetry of the driving force. This makes it possible to reduce the specific indicators of the metal consumption of vibrating machines and the energy consumption of the work performed.

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Dong, Jie, Yue Yang, and Zhi-Hui Wu. "Propagation characteristics of vibrations induced by heavy-haul trains in a loess area of the North China Plains." Journal of Vibration and Control 25, no. 4 (October 9, 2018): 882–94. http://dx.doi.org/10.1177/1077546318802980.

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To study heavy train-related vibration, this paper examines the world's largest heavy-freight railway – the Daqin Railway – to study the impacts of the seasonally frozen soil layer on vibrational acceleration. With increasing axle weight, the peak and mean values of the acceleration increased. Vibration acceleration attenuated the most from the shoulder to the embankment footing (51%–71%), while the vibrations at 70 m were attenuated by more than 90%. Certain measures must be taken by those living within 70 m of the railway shoulder. In addition, the acceleration peak caused by trains running in parallel after meeting amplified the vibration by 10%–39%. Moreover, the overall vibrations attenuate with increasing distance, whereas the local vibrations fluctuate. During the freezing period, the acceleration is 13%–26% greater than that of the unfrozen period. The vibration acceleration spectrum is comparatively wider, and is dominated by high-frequency components. Finally, using a three-dimensional model verified by field measurements, the vibrational features were analyzed at different embankment and foundation depths.

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Susastro, Susastro, and Novi Indah Riani. "Pendekatan Eksperimen Karakteristik Respon Getaran Sistem Two Degree of Freedom dengan Penambahan Independent Dual Dynamic Vibration Absorber." R.E.M. (Rekayasa Energi Manufaktur) Jurnal 3, no. 2 (May 2, 2019): 85. http://dx.doi.org/10.21070/r.e.m.v3i2.1729.

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Vibration is one of the problems that must be reduced in a vehicle. There are many ways to reduce vibration in vehicles, one of them is by adding Dynamic vibration absorber (DVA). While Dual Dynamic vibration absorber (dDVA) is a DVA period that is able to move in the translational direction given to the system to reduce translation vibration and when there is resonance. Translation DVA is an additional type of time used to reduce the vibration of the translation direction. So far there is not much research related to the use of translational DVA to reduce rotational vibrations as well as translation. In this study, a study was conducted related to the use of independent double translational DVA (dDVA) to reduce translation vibrations as well as rotation of the beam. The research was conducted by modeling the system obtained into mathematical equations and simulations were carried out to determine the characteristics of vibrations that arise. In the simulation, one of the DVA periods is placed at the center of the main system period, while the other DVA period is given a change between the center period and the end of the system. The results of the study show that the maximum reduction in translational vibration is 95.51% and occurs when the absorber is placed at the center of the system, while the maximum rotation vibration reduction is 56.62% and is obtained when the system is given with an arm ratio of 1 and zero.

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Cveticanin, L. "Period of vibration of axially vibrating truly nonlinear rod." Journal of Sound and Vibration 374 (July 2016): 199–210. http://dx.doi.org/10.1016/j.jsv.2016.03.027.

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Chang, Seongkyu. "Active Mass Damper for Reducing Wind and Earthquake Vibrations of a Long-Period Bridge." Actuators 9, no. 3 (August 7, 2020): 66. http://dx.doi.org/10.3390/act9030066.

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An active mass damper (AMD) was developed that uses a linear motor and coil spring to reduce the vertical vibration of a long-period cable-stayed bridge subjected to wind and earthquake loads. A scaled-down bridge model and AMD were fabricated, and the control effect of the AMD was investigated experimentally and analytically. The AMD was controlled via a linear quadratic Gaussian algorithm, which combines a linear quadratic regulator and Kalman filter. The dynamic properties were investigated using a 1/10 scale indoor experimental model, and the results confirmed that the measured and analytical accelerations were consistent. A vibrator was used to simulate the wind-induced vibration, and the experimental and analytical results were consistent. The proposed AMD was confirmed to damp the free vibration and harmonic load and increase the damping ratio of the bridge model from 0.17% to 9.2%. Finally, the control performance of the proposed AMD was numerically investigated with the scaled-down bridge model subjected to the El Centro and Imperial Valley-02 earthquakes. These results were compared with those of a TMD, and they confirmed that the proposed AMD could reduce excessive vertical vibrations of long-period cable-stayed bridges subjected to wind and earthquakes.

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Khomenko, Andrei P., Sergey K. Kargapoltsev, and Andrey V. Eliseev. "Development of Approaches to Creation of Active Vibration Control System in Problems of the Dynamics for Granular Media." MATEC Web of Conferences 148 (2018): 11004. http://dx.doi.org/10.1051/matecconf/201814811004.

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The article deals with the development of mathematical models and evaluation criteria of the vibration field in the dynamic interactions of the elements of the vibrational technological machines for the processes of vibrational strengthening of long-length parts with help of a steel balls working medium. The study forms a theoretical understanding of the modes of motions of material particles in interaction with a vibrating surface of the working body of the vibration machine. The generalized approach to the assessment of the dynamic quality of the work of vibrating machines in multiple modes of tossing, when the period of free flight of particles is a multiple of the period of the surface oscillations of the working body, is developed in the article. For the correction of vibration field of the working body, the characteristics of dynamic interactions of granular elements of the medium are taken into account using original sensors. The sensors that can detect different particularities of interaction of the granular medium elements at different points of the working body are proposed to evaluate the deviation from a homogeneous and one-dimensional mode of vibration field. Specially developed sensors are able to register interactions between a single granule, a system of granules in filamentous structures, and multipoint interactions of the elements in a close-spaced cylindrical structure. The system of regularization of the structure of vibration fields based on the introduction of motion translation devices is proposed using the multi-point sensor locations on the working body. The article refers to analytical approaches of the theory of vibration displacements. For the experimental data assessment, the methods of statistical analysis are applied. It is shown that the peculiar features of the motion of granular medium registered by the sensors can be used to build active control systems of field vibration.

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Chalah, Farid, Lila Chalah-Rezgui, Kamel Falek, Salah Eddine Djellab, and Abderrahim Bali. "Fundamental Vibration Period of SW Buildings." APCBEE Procedia 9 (2014): 354–59. http://dx.doi.org/10.1016/j.apcbee.2014.01.062.

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BASTRUKOV, S. I., J. W. YU, R. X. XU, and I. V. MOLODTSOVA. "RADIATIVE ACTIVITY OF MAGNETIC WHITE DWARF UNDERGOING LORENTZ-FORCE-DRIVEN TORSIONAL VIBRATIONS." Modern Physics Letters A 26, no. 05 (February 20, 2011): 359–66. http://dx.doi.org/10.1142/s0217732311034761.

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We study radiative activity of magnetic white dwarf undergoing torsional vibrations about axis of its own dipole magnetic moment under the action of Lorentz restoring force. It is shown that pulsating white dwarf can convert its vibration energy into the energy of magneto-dipole emission, oscillating with the frequency equal to the frequency of Alfvén torsional vibrations, provided that internal magnetic field is decayed. The most conspicuous feature of the vibration energy powered radiation in question is the lengthening of periods of oscillating emission; the rate of period elongation is determined by the rate magnetic field decay.

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An, Xue Li, Dong Xiang Jiang, Ming Hao Zhao, and Chao Liu. "Numerical Analysis of Coupled Lateral and Torsional Vibrations of a Vertical Unbalanced Rotor." Applied Mechanics and Materials 20-23 (January 2010): 352–57. http://dx.doi.org/10.4028/www.scientific.net/amm.20-23.352.

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A model for the coupled lateral and torsional vibrations of a vertical unbalanced rotor is developed. The equation of motion is obtained using Lagrangian dynamics without considering the external actuating forces and torque. The equation showed coupling and nonlinear interaction between the rotor lateral and torsional vibrations. Most of the earlier work on coupled vibrations has been done for the horizontal rotor model. The coupled vibrations for a vertical rotor have not been reported in the past. An attempt is made to reveal dynamic characteristics of vertical rotor. The results of the simulation showed the coupled between torsional and lateral vibrations is induced by mass eccentricity. Coupled vibrations have appeared in the start period of the vibration. After a transient vibration process, the vibrations are not coupling. The lateral vibration becomes equal amplitude with shafting speed. And the torsional vibration keeps on attenuating until it stops. When the vibration is coupled, the coupling effect on which torsional vibration to lateral vibration is evident. But there’s no coupling effect on the lateral to the torsional. It is also shown that for some operational parameters, the controlling action may excite large lateral vibrations due to coupling with the torsional motion.

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10

Yakimova, Natalya L., Vladimir A. Pankov, Aleksandr V. Lizarev, Viktor S. Rukavishnikov, Marina V. Kuleshova, Elena V. Katamanova, Evgeny A. Titov, and Dina V. Rusanova. "Neurophysiological and morphological effects in the post-exposure vibration period during experimental modeling." Russian Journal of Occupational Health and Industrial Ecology, no. 5 (May 31, 2019): 284–90. http://dx.doi.org/10.31089/1026-9428-2019-59-5-284-290.

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Introduction. Vibration disease continues to occupy one of the leading places in the structure of professional pathology. In workers after the termination of contact with vibration generalization and progression of violations in an organism is noted. The pathogenetic mechanisms of the progredient course of disturbances in the nervous system in the post-contact period of vibration exposure remain insufficiently studied.The aim of the study was to test an experimental model of vibration exposure to assess the neurophysiological and morphological effects of vibration in rats in the dynamics of the post-contact period.Materials and methods. The work was performed on 168 white male outbred rats aged 3 months weighing 180–260 g. The vibration effect was carried out on a 40 Hz vibrating table for 60 days 5 times a week for 4 hours a day. Examination of animals was performed after the end of the physical factor, on the 30th, 60th and 120th day of the post-contact period. To assess the long-term neurophysiological and morphofunctional effects of vibration in rats, we used indicators of behavioral reactions, bioelectric activity of the somatosensory zone of the cerebral cortex, somatosensory and visual evoked potentials, parameters of muscle response, morphological parameters of nervous tissue.Results. In the dynamics of the post-contact period observed the preservation of violations of tentatively research, motor and emotional components of behavior. In the Central nervous system instability of activity of rhythms of an electroencephalogram, decrease in amplitude of visual evoked potentials, lengthening of latency of somatosensory evoked potentials, decrease in total number of normal neurons and astroglia is established. In the peripheral nervous system remained changes in indicators: increasing duration and latency, reducing the amplitude of the neuromuscular response.Conclusions: The experimental model allows us to study the long-term neurophysiological and morphological effects of vibration on the body. The formation and preservation of changes in behavioral activity, neurophysiological and morphological effects of vibration from the 30th to the 120th day of the post-contact period were confirmed.

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Pakrashi, Vikram, Biswajit Basu, and Kevin Ryan. "Rapid Assessment of Natural Periods of Large Short-Period Civil Engineering Structures." Key Engineering Materials 569-570 (July 2013): 286–93. http://dx.doi.org/10.4028/www.scientific.net/kem.569-570.286.

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Rapid assessment of large, short-period structures is extremely important for establishing structural integrity. This paper demonstrates experimental non-contact detection of consistent frequency peaks from the ambient vibration of a range of large buildings. Long distance, remote Laser Doppler Vibrometry is employed to estimate the dominant response frequencies of these large building structures from their ambient vibration. These dominant frequencies were reproducible in the frequency domain. The results demonstrate potential field applications of this method in a number of important applications. Such applications include model-free and rapid assessment or monitoring of historical structures, strategically important structures, lifelines, assessment and monitoring of structures such as nuclear facilities and rapid evaluation of large scale structures following disasters. Empirical formulas specified in codes do not cover such special structures and experimental determination of periods employing the method proposed may thus become essential.

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Aydın, Şenay, Markus Kofler, Yeliz Bakuy, Ayşegül Gündüz, and Meral E. Kızıltan. "Effects of vibration on cutaneous silent period." Experimental Brain Research 237, no. 4 (January 18, 2019): 911–18. http://dx.doi.org/10.1007/s00221-018-05463-1.

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Escaler, Xavier, and Toufik Mebarki. "Full-Scale Wind Turbine Vibration Signature Analysis." Machines 6, no. 4 (December 7, 2018): 63. http://dx.doi.org/10.3390/machines6040063.

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A sample of healthy wind turbines from the same wind farm with identical sizes and designs was investigated to determine the average vibrational signatures of the drive train components during normal operation. The units were variable-speed machines with three blades. The rotor was supported by two bearings, and the drive train connected to an intermediate three-stage planetary/helical gearbox. The nominal 2 MW output power was regulated using blade pitch adjustment. Vibrations were measured in exactly the same positions using the same type of sensors over a six-month period covering the entire range of operating conditions. The data set was preliminary validated to remove outliers based on the theoretical power curves. The most relevant frequency peaks in the rotor, gearbox, and generator vibrations were detected and identified based on averaged power spectra. The amplitudes of the peaks induced by a common source of excitation were compared in different measurement positions. A wind speed dependency of broadband vibration amplitudes was also observed. Finally, a fault detection case is presented showing the change of vibration signature induced by a damage in the gearbox.

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Nguyen, Thanh Q., Thao D. Nguyen, Lam Q. Tran, and Nhi K. Ngo. "A New Insight to Vibration Characteristics of Spans under Random Moving Load: Case Study of 38 Bridges in Ho Chi Minh City, Vietnam." Shock and Vibration 2020 (November 4, 2020): 1–20. http://dx.doi.org/10.1155/2020/1547568.

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We propose a novel representative power spectrum density as a specific characteristic for showing responses of spans during a long operational period. The idea behind this method is to use the representative power spectrum density as a powerful tool to evaluate the stiffness decline of spans during their operation period. In addition, a new measurement method has been introduced to replace the traditional method of monitoring the health conditions of bridges through a periodic measurement technique. This helps to reduce costs when carrying out testing bridges. Besides, the proposed approach can be widely applied not only in Vietnam but also in many other underprivileged countries around the world. Obtained results show that, during the operational process of spans, there is not only a pure vibration evaluation such as bending vibration and torsion vibration tests but also a combination of various vibration types including bending-torsion vibration or high-level vibrations like first-mode bending and first-mode torsion. Depending on each type of structure and material properties, different types of vibrations will appear more or less during the operational process of spans under a random moving load. Furthermore, the representative power spectrum density is also suitable for evaluating and determining many different fundamental vibrations through the same measurement time as well as various measurement times.

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Inel, Mehmet, Hayri Baytan Ozmen, and Bayram Tanik Cayci. "Determination of Period of RC Buildings by the Ambient Vibration Method." Advances in Civil Engineering 2019 (September 22, 2019): 1–10. http://dx.doi.org/10.1155/2019/1213078.

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Determining the dynamic properties of structures is important for understanding their seismic behaviour. Ambient vibration signal measurement is one of the approaches used to determine the period of structures. Advantages of this method include the possibility of taking real-time records and presenting nondestructive and rapid solutions. In this study, natural vibration periods are calculated by taking ambient vibration signal records from 40 buildings. The height of the building, infill wall effect, presence of seismic retrofit, and presence of damage are taken into consideration, and their effects on natural vibration periods are investigated. Moreover, the results are compared with the analytical methods to reveal the differences. A significant correlation between the period and height of the building is observed. It is seen that the natural vibration periods of the buildings decrease by 7% to 30% (15% on average) due to infill wall contribution. However, the efficiency of infill walls decreases as the building height increases. Another significant result is that adding shear walls substantially decreases the vibration period values by 23% to 33% with respect to the shear wall ratio. When the analytical estimates and measured building period results are compared, it is seen that analytical models have closer period estimates before infill walls are implemented. The limited data in scope of the study suggest that significant differences may present in the analytical and measured periods of the buildings due to infill wall contributions.

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Lugovoi, V. P., and V. V. Lugovoi. "Comparative Analysis of Vibrations of Ring-Shaped Ultrasonic Concentrators." Science & Technique 20, no. 2 (April 8, 2021): 121–26. http://dx.doi.org/10.21122/2227-1031-2021-20-2-121-126.

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The paper provides a comparative analysis of the influence of ring concentrator shape in ultrasonic systems on their amplitude-frequency characteristics. Devices are known in which elastic elements are used either as resonators or as working tools of ultrasonic technological systems. However, the use of elastic elements as concentrators of ultrasonic vibrations is insufficiently studied and requires comprehensive research and development of recommendations for their practical application. For this purpose, a theoretical analysis has been carried out in the paper while using the ANSYS computer program, which made it possible to perform modal and harmonic analysis of ring models with various shapes. The round ring has a nominal outer diameter of 50 mm and a variable cross-section. Three ring models have been analyzed: one round model and two models of oval shape. To conduct a comparative analysis and identify frequencies at which resonance occurs, the vibration characteristics of the rings have been considered in the frequency range from 1 to 26 kHz. Results of the analysis show that, depending on the frequency of forced vibrations, bending vibrations are formed in the rings, which act in different coordinate planes. In this case, a change in the shape of the rings is accompanied by a change in the amplitude of the bending vibrations. The most intense ring vibrations along the vertical axis have been achieved in circular rings. It has been found that with an increase in the frequency of forced oscillations, an increase in the number of oscillation periods is observed. If in the region of low vibration frequencies only a one-period vibration mode is formed in the ring, then in the region of ultrasonic vibrations the number of vibration periods increases to two and three. All the considered ring models have several natural vibration frequencies with a certain periodicity in different coordinate planes depending on the shape of the rings. The intensity of the vibrations is different in different directions and depends on the shape and frequency of the forced vibrations. Examples of vibration mode variations for various ring shapes are demonstrated in the paper.

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Seo, Moonbok, Sanghoon Kwon, and Bongjik Lee. "Improvement of Grouting by Short-period Vibration Energy." Journal of the Korean Geoenvironmental Society 16, no. 7 (July 1, 2015): 35–42. http://dx.doi.org/10.14481/jkges.2015.16.7.35.

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Winterflood, J., and D. G. Blair. "A long-period conical pendulum for vibration isolation." Physics Letters A 222, no. 3 (October 1996): 141–47. http://dx.doi.org/10.1016/0375-9601(96)00619-6.

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Zhang, Jianjun, Qibo Ni, Jing Wang, and Feng Guo. "Transient thermal elastohydrodynamic lubrication of point contacts subjected to normal vibration." Industrial Lubrication and Tribology 68, no. 5 (August 8, 2016): 536–47. http://dx.doi.org/10.1108/ilt-06-2015-0085.

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Purpose Vibration exists widely in all machineries working under high speed. The unpredictability of vibration and the change of the relative surface speed may result in difficulties in the elastohydrodynamic lubrication (EHL) analysis. By far, few studies on EHL relating to vibration have been published. The purpose of the present study is to investigate the effect of the vertical vibrations and the influence of temperature on the thermal EHL contacts. Design/methodology/approach The lubricant was assumed to be Newtonian fluid. The time-dependent numerical solutions were achieved instant after instant in each period of the vibration. At each instant, the pressure field was solved with a multi-level technique, the surface deformation was solved with a multi-level multi-integration method and the temperature filed was solved with a finite different scheme through a sweeping progress. The periodic error was checked at each end of the vibration period until the responses of pressure, film thickness and temperature were all periodic functions with the frequency of the roller’s vibrations. Findings The results reveal that normal vibration produces little drastic change of pressure, film thickness and temperature in EHL. Under some conditions, the vibrations of the roller can produce transient dimples within the contact conjunction. It is also showed that the lubrication in the same sliding is better than the opposite sliding. Research limitations/implications For the unpredictability of vibration, it is not easy to do the experiment to realize a real comparison with numerical results. The reach does not show any verification and consider the effect of non-Newtonian fluid. Originality/value The effect of the vertical vibrations on the thermal EHL point contact hast been studied. The effects of both the amplitude and the frequency on the predicted load-carrying capacity, minimum film thickness, center pressure and center temperature and the coefficient of friction were investigated. The role of the thermal effect was given.

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Pastukhova, Lilia, Vladimir Alekhin, Sergey Gorodilov, and Antonina Sekacheva. "NUMERIC ANALYSIS OF VIBRATION IMPACT OF SUBWAY ON MULTI-STOREY BUILDING." Akustika 34 (November 1, 2019): 59–65. http://dx.doi.org/10.36336/akustika20193459.

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The authors carried out the numerical analysis of vibration impact of subway on the multistory residential building. Supposed building site is situated in Yekaterinburg and placed above the subway line tunnels in the middle of the track between the stations. The analysis is aimed to simulate the initiation of vibration during the period when the train passes, to assess the impact of availability of vibration-damping layer on this process, and also to obtain values of vibrational accelerations in order to predict vibration levels and volumes of sound in reference points in living spaces.

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KILIKEVIČIUS, Artūras, Darius BAČINSKAS, Mindaugas JUREVIČIUS, Kristina KILIKEVIČIENĖ, Antanas FURSENKO, Jonas JAKAITIS, and Eligijus TOLOČKA. "FIELD TESTING AND DYNAMIC ANALYSIS OF OLD CONTINUOUS TRUSS STEEL BRIDGE." Baltic Journal of Road and Bridge Engineering 13, no. 1 (March 27, 2018): 54–66. http://dx.doi.org/10.3846/bjrbe.2018.394.

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Paper presents dynamic field test and analysis results of a three span railway steel continuous truss bridge over river Neris in Jonava. Bridge was originally constructed in 1914. In the period of the World War II and afterwards the bridge was many time destroyed by German and Soviet armies. In 1948 the new railway bridge was constructed. Object of the present paper is to evaluate dynamic behaviour of the railway bridge after 67 years in service. Experimental dynamic analysis was divided into resonance-vibration, forced-vibration and free vibration studies. Resonance-vibrations of the bridge were excited by separate actions of shock loading and standard locomotive 2M62. Forced-vibrations were measured under the action of locomotive 2M62. Additionally, free vibration tests under passage of freight and passenger trains have been carried out. Structural dynamic response of the bridge was analysed using Brüel & Kjær LAN XI dynamic test system and software. As a result, main dynamic parameters of the bridge were obtained. The main results include: mode shapes, frequencies of natural and forced vibrations, damping ratios, maximum amplitudes of accelerations, dynamic displacements. The obtained values were compared to the requirements of different design codes. Based on the achieved results concluding remarks and recommendations regarding the condition of the bridge after long-term period in service were presented.

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Cvetanovic, Boban, Dragan Cvetković, Momir Praščević, Miljan Cvetković, and Milan Pavlović. "An analysis of the impact of agricultural tractor seat cushion materials to the level of exposure to vibration." Journal of Low Frequency Noise, Vibration and Active Control 36, no. 2 (June 2017): 116–23. http://dx.doi.org/10.1177/0263092317711983.

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During everyday operations with tractors, drivers are exposed to harmful effects of various factors. In addition to unfavourable temperature and humidity, dust and noise, one of the factors harmful to driver’s health is vibrations. They come from the tractor engine and from the roughness of the ground and are transferred to the cab and through the seat to the body of the driver. In case of high level magnitude vibrations and a long period of exposure to them, many health problems occur. The harmful effect of the vibrations is especially obvious in older models of tractors. High intensities of vibrations (above permitted limits) were found during the measurements of vibrations at the driver seat in such tractors. This study is an attempt to reduce the vibration levels using various vibration-absorbing components, such as cushions, at driver’s seat. The results of the measurements showed that the vibration levels were significantly lower in comparison to original seats.

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Lapole, Thomas, and Chantal Pérot. "Hoffmann reflex is increased after 14 days of daily repeated Achilles tendon vibration for the soleus but not for the gastrocnemii muscles." Applied Physiology, Nutrition, and Metabolism 37, no. 1 (February 2012): 14–20. http://dx.doi.org/10.1139/h11-129.

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In a previous study, Achilles tendon vibrations were enough to improve the triceps surae (TS) activation capacities and also to slightly increase TS Hoffmann reflex (H-reflex) obtained by summing up soleus (Sol) and gastrocnemii (GM and GL) EMGs. The purpose of the present study was to analyze separately Sol and GM or GL reflexes to account for different effects of the vibrations on the reflex excitability of the slow soleus and of the gastrocnemii muscles. A control group (n = 13) and a vibration group (n = 16) were tested in pre-test and post-test conditions. The Achilles tendon vibration program consisted of 1 h of daily vibration (frequency: 50 Hz) applied during 14 days. Maximal Sol, GM and GL H-reflexes, and M-waves were recorded, and their Hmax/Mmax ratios gave the index of reflex excitability. After the vibration protocol, only Sol Hmax/Mmax was enhanced (p < 0.001). The enhanced Sol reflex excitability after vibration is in favor of a decrease in the pre-synaptic inhibition due to the repeated vibrations and the high solicitation of the reflex pathway. Those results of a short period of vibration applied at rest may be limited to the soleus because of its high density in muscle spindles and slow motor units, both structures being very sensitive to vibrations.

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Mohamed, Ahmed Nader, Khaled F. El Kashif, and Hamed M. Salem. "An Investigation of the Fundamental Period of Vibration for Moment Resisting Concrete Frames." Civil Engineering Journal 5, no. 12 (December 1, 2019): 2626–42. http://dx.doi.org/10.28991/cej-2019-03091438.

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The determination of fundamental period of vibration for structures is essential to earthquake design. The current codes provide empirical formulas to estimate the approximated fundamental period and these formulas are dependent on building material, height of structure or number of stories. Such a formulation is excessively conservative and unable to account for other parameters such as: length to width ratios, vertical element size and floors area. This study investigated the fundamental periods of mid-rise reinforced concrete moment resisting frames. A total of 13 moment resisting frames were analyzed by ETABS 15.2.2, for gross and cracked eigenvalue analysis and Extreme Loading for Structures Software® or ELS, for non-linear dynamic analysis. The estimated periods of vibration were compared with empirical equations, including current code equations. As expected, the results show that building periods estimated based on simple equations provided by earthquake design codes in Europe (EC8) and America (UBC97 and ASCE 7-10) are significantly smaller than the periods computed using nonlinear dynamic analysis. Based on the results obtained from the analyzed models, equations for calculating period of vibration are proposed. These proposed equations will allow design engineers to quickly and accurately estimate the fundamental period of moment resisting frames with taking different length to width ratios, vertical element size, floors area and building height into account. The interaction between reduction factor and the reduced period of vibration is studied, and it is found that values of maximum period of vibration can be used as an alternative method to calculate the inelastic base shear value without taking reduction factors in consideration.

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Chen, Wen-Li, Donglai Gao, Shujin Laima, and Hui Li. "A Field Investigation on Vortex-Induced Vibrations of Stay Cables in a Cable-Stayed Bridge." Applied Sciences 9, no. 21 (October 27, 2019): 4556. http://dx.doi.org/10.3390/app9214556.

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A field study was conducted to identify the vortex-induced vibrations (VIVs) of stay cables in a cable-stayed bridge. A full-scale health-monitoring system was established to observe the wind effects of the selected cables. The vibration amplitudes in the twenty selected stay cables were first studied. The results indicate that only cable CAC20 has large amplitudes with a multimode and high-frequency vibration in the investigated period. The correlation between the wind and cable vibration was subsequently investigated. The large vibration amplitudes are primarily located in the mean speed scope of 4 to 6 m/s, simultaneously close to the reduced velocity of five when the wind was almost perpendicular to the bridge axis and had a smaller turbulence intensity. Moreover, the relationship between the maximum vibration amplitude with the mean wind speed was fitted by a function that was validated by the measured data. Finally, an estimation method was presented to predict the participative vibration modes that would happen in the VIVs of the stay cables, according to the known wind and cable parameters. The measured cable vibrations were employed to validate this estimation method. The results indicate the estimated vibration modes are close to the measured vibration modes.

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Zhao, Shi Quan, Bo Xue Liu, Yong Quan Wang, and Hua Ling Chen. "Vibration Reduction of Pipe Systems Using Phononic Crystals." Advanced Materials Research 694-697 (May 2013): 354–60. http://dx.doi.org/10.4028/www.scientific.net/amr.694-697.354.

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The vibration of pipe systems not only worsens their working environment, but also may result in the loosening of mechanical connections between pipelines, as well as the structural fatigue damages. This paper presents a new method for vibration control of pipe systems, by specially designing some pipe structures based on two vibration reduction mechanisms of phononic crystals, for the vibration frequency in the actual tests. Some numerical analyses are then performed about the effects of the parameters of vibrator, for instance, the ratio of material components, and the numbers of period. The simulation results demonstrate that the proposed phononic crystals structures can reduce the vibration of pipe systems effectively.

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Dapeng, Zhu, Qin Liangkai, and Lin Yundian. "Analytical Study on Dynamic Response of Deep Foundation Pit Support Structure under the Action of Subway Train Vibration Load: A Case Study of Deep Foundation Pit of the New Museum Near Metro Line 2 in Chengdu, China." Shock and Vibration 2015 (2015): 1–10. http://dx.doi.org/10.1155/2015/535196.

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Presently, foundation pit support structures are generally regarded as the temporary structures and the impact of vibration loads is often overlooked. As opposed to static and seismic loads, the vibration loads of subway trains are a type of cyclic load with a relatively long duration of action and a definite cycle; it is of great importance for the design of foundation pit support structures to correctly evaluate the impact of subway train vibrations on deep foundation pit and support works. In this paper, a dynamic three-dimensional numerical model is built that considers the vibration load of subway trains on the basis of the static numerical model for deep foundation pit support structures and simplified train loads to study the impact of train vibrations on deep foundation pit and permanent support structures. Studies have shown that the dynamic response of surface displacement mainly occurs in the early period of dynamic load, the vibration load of subway trains has little impact on ground subsidence, the support pile structure is in an elastic state during dynamic response under the action of subway train vibrations, and the action of train vibration loads is inimical to the safety of foundation pit support structures and should be closely studied.

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Isobe, Hiromi, Masatoshi Okuda, Keisuke Hara, and Jun Ishimatsu. "Effect of Vibration Direction of Ultrasonic Vibrating Cutting Edge on Internal Stress Fluctuation of Workpiece." International Journal of Automation Technology 15, no. 4 (July 5, 2021): 457–65. http://dx.doi.org/10.20965/ijat.2021.p0457.

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The aim of this study is to investigate the dynamic phenomenon of ultrasonic vibration-assisted cutting by utilizing a stress distribution visualization system. The vibrating cutting-edge is considered to be a cause of dynamic changes in the cutting force at ultrasonic frequencies. However, many researchers have explained the effect of ultrasonic vibration-assisted cutting by evaluating the time-averaged cutting force, because existing dynamometers are unable to measure the dynamically changing cutting force at ultrasonic frequencies. There are some reports that the vibration direction of cutting edge strongly affects tool wear. However, in practical ultrasonic cutting, the vibration of the cutting edge has yet to be measured in a production environment. In this study, the instantaneous stress distribution on the workpiece was visualized by a photoelastic method that combines a pulsed laser emission synchronized with tool vibration. The developed photographic system can capture 360 frames in one ultrasonic vibration period. The dynamic cutting force was calculated by Flamant’s stress distribution theory. It was experimentally confirmed that the stress distribution under vibration-assisted conditions showed periodical changes synchronized with vibration. Because these results are compatible with well-known vibration-cutting theories, the imaging system was able to show the periodic changes in stress distribution in the ultrasonic frequency band. This indicates that the dynamic change in cutting force during the ultrasonic vibration period affects intermittent cutting conditions. In this report, the vibration direction was adjusted from −9.5° to +9.5° along the cutting direction. When the tool moved in upwards for the cutting phase and downwards for withdrawal phase, the stress distribution was continuously observed over one tool vibration period; no intermittent cutting was observed. The locus of the cutting force vector was affected by the ultrasonic vibration direction and rake angle of the cutting tool. A negative rake angle showed that the direction of the cutting force vector shifted toward the workpiece side near the most advanced position of the cutting edge.

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Wu, Chu Qun, Fan Wang, and Shao Yong Wang. "Dynamic Analysis of Large Steel Structure Truss System." Applied Mechanics and Materials 101-102 (September 2011): 387–91. http://dx.doi.org/10.4028/www.scientific.net/amm.101-102.387.

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The deformation of the large steel structure truss system, which was subjected to constant loads, variable loads and wind loads, was calculated by using the 3D3S steel structure analysis program. The periods and the vibration mode from the first to the ninth order of the structure were obtained by the earthquake vibration mode period analysis. The dynamic computation of the structure showed that the period difference of the vibration modes is small. The frequencies and the modes of vibration from the first to the ninth order of the same structure mode were calculated by using the ANSYS finite element program. The frequencies and the modes of vibration from the first to the ninth order of the building were obtained by the dynamic analysis of the structure. The dynamic computation of the structure shows that the frequencies difference of the vibration modes is small. The vibration instability is possible for the structure.

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JOSHI, S. G., and KWATRA NAVEEN. "EFFECT OF GEOMETRY OVER THE FUNDAMENTAL PERIOD OF VIBRATION." i-manager's Journal on Structural Engineering 8, no. 1 (2019): 28. http://dx.doi.org/10.26634/jste.8.1.15440.

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Yang, Lei, Yao Li, Qiongzheng Lin, Huanyu Jia, Xiang-Yang Li, and Yunhao Liu. "Tagbeat: Sensing Mechanical Vibration Period With COTS RFID Systems." IEEE/ACM Transactions on Networking 25, no. 6 (December 2017): 3823–35. http://dx.doi.org/10.1109/tnet.2017.2769138.

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TAUE, Katsuhira, and Tadayoshi KOIZUMI. "212 Constructing Period Waveform and Characteristics of Nonlinear Vibration." Proceedings of Conference of Hokkaido Branch 2008.47 (2008): 55–56. http://dx.doi.org/10.1299/jsmehokkaido.2008.47.55.

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Huang, Yi, and Hui Li. "Chaos and period-doubling vibration in superconducting levitation systems." AIP Advances 10, no. 9 (September 1, 2020): 095121. http://dx.doi.org/10.1063/5.0020899.

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Zhang, Xiaodong, Shuguang Liu, Changwang Yan, Xiaoxiao Wang, and Huiwen Wang. "Effects of Vehicle-Induced Vibrations on the Tensile Performance of Early-Age PVA-ECC." Materials 12, no. 17 (August 21, 2019): 2652. http://dx.doi.org/10.3390/ma12172652.

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Polyvinyl alcohol-engineering cementitious composites (PVA-ECCs) have been widely applied in bridge deck repairing or widening, and a common practice is that a portion of the bridge is left open to traffic while the closed portion is constructed, which exposes the early-age PVA-ECC to vehicle-induced vibrations. However, whether vehicle-induced vibrations affect the performance of early-age PVA-ECC remains unknown. The purpose of this study was to conduct laboratory test programs to investigate to what extent vehicle-induced vibrations soon after installation affects the tensile performance of the PVA-ECC. A self-improved device was used to simulate the vehicle-induced vibrations, and after vibrating with the designed variables, both a uniaxial tensile test and a grey correlation analysis were performed. The results indicated that the effects of vehicle-induced vibrations on the tensile performance of early-age PVA-ECCs were significant, and they generally tended to be negative. In particular, for all of the vibrated PVA-ECC specimens, the most negative effects occurred when vibration occurred during the period between the initial set and the final set. We concluded that although vehicle-induced vibrations during the setting periods had no substantial effects on the inherent strain-hardening characteristics of PVA-ECCs, the effects should not be ignored.

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Iwakura, Izumi, Atsushi Yabushita, Jun Liu, Kotaro Okamura, Satoko Kezuka, and Takayoshi Kobayashi. "A new reaction mechanism of Claisen rearrangement induced by few-optical-cycle pulses: Demonstration of nonthermal chemistry by femtosecond vibrational spectroscopy." Pure and Applied Chemistry 85, no. 10 (October 1, 2013): 1991–2004. http://dx.doi.org/10.1351/pac-con-12-12-01.

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Time-resolved vibration spectroscopy is the only known way to directly observe reaction processes. In this work, we measure time-resolved vibration spectra of the Claisen rearrangement triggered and observed by few-optical-cycle pulses. Changes in molecular structure during the reaction, including its transition states (TSs), are elucidated by observing the transient changes of molecular vibration wavenumbers. We pump samples with visible ultrashort pulses of shorter duration than the molecular vibration period, and with photon energies much lower than the minimum excitation energy of the sample. The results indicate that the “nonthermal Claisen rearrangement” can be triggered by visible few-optical-cycle pulses exciting molecular vibrations in the electronic ground state of the sample, which replaces the typical thermal Claisen rearrangement.

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Necula, Maria, Dorin Bibicu, and Luminița Moraru. "Vibration of rectangular plates: fundamental mode and integer multiple of the fundamental period of vibration." Annals of the ”Dunarea de Jos” University of Galati. Fascicle II, Mathematics, Physics, Theoretical Mechanics 42, no. 1 (July 28, 2019): 43–48. http://dx.doi.org/10.35219/ann-ugal-math-phys-mec.2019.1.06.

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Taş, Süleyman. "The Effects of Vibration and Pressure Treatments in the Early Postoperative Period of Rhinoplasty." Aesthetic Surgery Journal 40, no. 6 (August 13, 2019): 605–16. http://dx.doi.org/10.1093/asj/sjz226.

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Abstract Background The early postoperative period can be distressing for the patients undergoing rhinoplasty since edema and ecchymosis are common complications. Objectives To analyze the effects of the vibration and pressure treatments in the early postoperative period of rhinoplasty. Methods Sixty patients, who had undergone rhinoplasty, were randomized into 3 groups: group 1 (control group, n = 20) received classic nasal casting, group 2 (n = 20) received nasal cast with an elastic bandage to hold it on the face, and group 3 (n = 20) received vibration treatment in addition to that in group 2 following the rhinoplasty. They were evaluated preoperatively and postoperatively at 3 and 7 days in a prospective study. The postoperative edema and ecchymosis were scored by 2 independent surgeons. The postoperative pain was measured using the visual analog scale, and the necessity of anti-inflammatory medication (and the dose needed) and the cast comfort was questioned. The sebaceous activity of the nose skin was examined. A preoperative and postoperative seventh day sonographic study was performed to evaluate the tissue edema objectively. Results The pressure treatment decreased the edema and ecchymosis significantly compared with the control group. The vibration treatment minimized edema, ecchymosis, sebaceous activity of the nose skin, pain score, and the need for anti-inflammatory medication, and increased the cast comfort significantly compared with the other groups (P < 0.0001). Conclusions Rapid regression of edema and ecchymosis may be achieved using the vibrating nasal cast technique that may minimize patient discomfort, pain, and sebaceous activity following rhinoplasty. Level of Evidence: 1

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Lu, Guanya, Kehai Wang, and Weizuo Guo. "Vibration characteristic analyses of medium-and small-span girder bridge groups in highway systems based on machine learning models." Advances in Structural Engineering 24, no. 11 (March 3, 2021): 2336–50. http://dx.doi.org/10.1177/1369433221997722.

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There are large amounts of small-and medium-span girder bridges which bear structural similarity, while the large-scale bridge structures are generally limited in the timely applications of structural vibration characteristics. Therefore, in this study a framework based on machine learning models was proposed to analyze the vibration characteristics of specific line bridge groups. The probability distributions of structural, geometric, and material properties of bridge groups in specific lines were obtained using statistical tools and a Latin hypercube sampling method was used to generate reasonable sample sets for the bridges group, and parameterized finite element models of the bridges were established. Then, the optimal models were tuned and determined to predict fundamental mode and period by the 10-fold cross-validation method applying the numerical simulation results. This study’s results showed that the random forest models divided the vibration modes of the bridge groups into the longitudinal vibrations of the main girders and the longitudinal vibrations of the adjacent spans and side piers with a classification accuracy of greater than 90%, while the artificial neural network models exhibited the lowest normalized mean square error for the periods. The periods mainly ranged between 0.7 and 1.5 s. Furthermore, the bearing settings, ratios of the pier height to section diameters, and boundary types were determined to be the most significant properties influencing the fundamental modes and periods of the examined bridges, by respectively observing the reduced value of the random forest Gini indices and distribution of the generalized weight value of the input variables in artificial neural networks. This study provides an intelligent and efficient method for obtaining vibration characteristics of bridges group for a specific network.

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Zhang, Rong Hai, Ning Yuan Zhu, and Gai Pin Cai. "Surface Effect Mechanism Analysis for Vibrational Rotary Forging." Advanced Materials Research 314-316 (August 2011): 753–58. http://dx.doi.org/10.4028/www.scientific.net/amr.314-316.753.

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As a contact of vibrational rotary forging is highly nonlinear, the contact area and boundary between rotary toolhead and workpiece had more accurate calculation, made the contact boundary more tally with the actual situation. For a surface effect is of complexity for vibrational rotary forging, a vibrational rotary forging visco-elasticity plasticity model was built, and the visco-elasticity spatial matrix and the visco-plasticity spatial matrix were derived by the generalized Hooke's law in elasticity theory and the increase theory in mechanics of plasticity, then by the finite element founction of MATLAB for the surface effect analyzed during the vibrational rotary forging deformation, it is shown as blow: the surface effect should be appeared with high frequency vibration or low frequency vibration, but there are some conditions for surface effect produced during plastic process, and then the hypothesis that the friction vector is reversal of deformation load, and it is benefit to deformation process during the part of time in vibration period is validated.

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Huang, Yan, and Song Lin He. "Experimental Study on the Vertical Vibration of Symmetrical Double Spring-Mass System." Applied Mechanics and Materials 778 (July 2015): 24–27. http://dx.doi.org/10.4028/www.scientific.net/amm.778.24.

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The free vibration along with the vertical direction of the symmetric double spring –mass system has been studied with experimental method. It is discovered that when the distance between two suspending points is not zero, the vibration of symmetrical double spring mass system along the vertical direction is nonlinear. The period of the system increases with the increase of the amplitude and distance of suspending points. The equivalent mass coefficient of the system vibrating nonlinearly is greater than that of the system vibrating harmonically and is related to inclination degree and relative elongation of the spring.

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Tremblay, Robert. "Fundamental Periods of Vibration of Braced Steel Frames for Seismic Design." Earthquake Spectra 21, no. 3 (August 2005): 833–60. http://dx.doi.org/10.1193/1.1989358.

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An analytical study is performed to propose a simple expression for the fundamental period of vibration of concentrically braced steel frames. This work was carried out in the context of the development of the 2005 National Building Code of Canada (NBCC) and is mainly applicable to structures located in moderate and low seismic regions. Available field and test measurements of building periods are compared to analytical predictions. An empirical period formula is developed based on a survey of analytically computed building periods published in the literature. The influence of the 2005 NBCC design provisions on braced steel-frame periods is examined through a closed-form period solution and an extensive parametric study. Building periods are found to vary significantly with seismic hazard levels and soil conditions. An expression is tentatively proposed that provides reasonable lower-bound period estimates for most situations in Canada.

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Zhang, Wei Pan, Guoan Yang, and Zhi Yong Zhou. "The Vibration Analysis and Improvements of Compressor and Pipeline for Reforming Hydrogen Device." Advanced Materials Research 562-564 (August 2012): 1003–6. http://dx.doi.org/10.4028/www.scientific.net/amr.562-564.1003.

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Excessive vibration was observed from hydrogen reciprocating compressor pipelines since the capacity expansion revamping of this unit finished in a refinery. The production had been frequently stopped since the vibrations on the pipelines exceeded the alarm value, which often led to a delivery failure of Hydrogen for subsequent reactions, causing great economic losses. In order to identify the root cause of vibration, reduce the airflow pulse peak, and enhance the pipeline security strength and rigidity of the structure, a comprehensive analysis on the reciprocating compressor and pipeline system was conducted. The vibration has been constrained in an acceptable range after the adjustment，and the unit has gotten a long-period and stable operation.

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Ostendorf, C. "The Influence of a Noise Barrier on Nuisance Caused by Vibrations." Journal of Low Frequency Noise, Vibration and Active Control 24, no. 4 (December 2005): 251–64. http://dx.doi.org/10.1260/026309205776232781.

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Since the construction of a noise barrier beside the motorway near their home, a family suffers from nuisance caused by vibration. Prior to the building activities of the noise barrier there had never been a problem with vibration. The family is convinced that the noise barrier in some way introduces or amplifies the vibration caused by traffic using the motorway. In order to find the cause of the vibration and the relevance of the noise barrier, vibration measurements have been done. These measurements show that the traffic using the motorway is indeed the main cause of the vibration in the building. The noise barrier, however/has no influence on the vibrations. The fact that nuisance occurred in the same period as the building activities, is mainly due to the fast decline of the road-surface influenced by the building activities. The measurements also showed that the floor (especially the bedroom floor) reacted very strongly to vibration with a dominant frequency of 17 Hz. To reduce the vibration, it has been advised that the road-surface of the motorway be renewed and the possibility of modifying the floor to reduce the 17Hz resonance be considered.

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Ren, Fushen, Baojin Wang, and Suli Chen. "Nonlinear Modeling and Qualitative Analysis of Coupled Vibrations in a Drill String." International Journal of Bifurcation and Chaos 28, no. 10 (September 2018): 1850119. http://dx.doi.org/10.1142/s0218127418501195.

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A coupled model for axial/torsional/lateral vibrations of the drill string is presented, in which the nonlinear dynamics and qualitative analysis method are employed to find out the key factors and sensitive zone for coupled vibration. The drill string is simplified as an equivalent shell under axial rotation. After dimensionless processing, the mathematical model for coupled axial/torsional/lateral vibrations of the drill string is obtained. The Runge–Kutta–Fehlberg method is employed for the numerical simulation, and the rules that govern the changing of the torsional and axial excitation are revealed. And the stability domains of the explicit Runge–Kutta method are analyzed. Furthermore, the suggestions for field applications are also presented. It is demonstrated by simulation results that the lateral/axial/torsional vibrations exist simultaneously and couple with each other. The system will obtain a stable period motion with an axial excitation zone before the coupled vibration in the three directions, and continue to increase the axial excitation to cause the coupled vibration easily. The torsional excitation of the drill string mainly contributes to the coupled vibration in the three directions when in a specific rotation speed zone. The system is more likely to obtain a periodic motion through adjusting the torsional excitation out of this zone.

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Liu, Panxue, Shuguang Zuo, Xudong Wu, and Minghai Zhang. "A method for determining the minimum period number in finite locally resonant phononic crystal beams." Journal of Vibration and Control 26, no. 9-10 (January 3, 2020): 801–13. http://dx.doi.org/10.1177/1077546319889851.

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To achieve the target band-gap in finite locally resonant phononic crystal beams, a method for determining the minimum period number is proposed. The vibration transmissibility method is extended to deal with the finite locally resonant phononic crystal beam. Comparing the vibration attenuation region obtained from the transmissibility method with the band-gap from the conventional transfer matrix method, the minimum period number can be calculated. Based on two forming patterns of locally resonant phononic crystal beams, the effects of the lattice constant and structural parameters of resonators on the band-gap as well as the influence of the period number on the vibration transmission characteristic are investigated. The minimum period number method can improve the applicability of the transmissibility method in the design of band-gaps and overcome the drawback that the transfer matrix method lacks the actual vibration attenuation. Finally, a comprehensive index is introduced to evaluate the effect of vibration reduction.

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Huang, Zhi Bo, Cong Mou Lin, Jin Shan Huang, Ying Chen, and Fan Bing Meng. "The Research on the Structure Response of Underwater Blasting on 4-Story Masonry-Concrete Building." Advanced Materials Research 163-167 (December 2010): 2521–27. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.2521.

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This article takes the Xiamen Sea reef engineering as an example to research the structure response of underwater blasting vibration on 4-story masonry-concrete building. The blasting seismic wave has been field monitored and the data has been analyzed with some means such as wavelet analysis. As a result, the characteristic laws of different floors’ structure responses under the effect of blasting vibration load have been acquired. With the floor increasing, the particles vibration velocity amplification coefficient of the forth top roof relative to the ground is approximately 1.36 to 2.086. The duration period and the main vibrationa are reduced respectively by 14%-28% and by 38%-56%; each floor’s vibration energy mostly concentrates in 0-25Hz’s band. The first floor’s energy mainly concentrates on 0-60ms, mainly distributing in 1st and 2nd frequency band, with the maximum appearing in the 1st band. And the vibration signal energy peak amplification coefficient relative to the ground is approximately 1.783 to 3.866.

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Guler, Kadir, Ercan Yuksel, and Ali Kocak. "Estimation of the Fundamental Vibration Period of Existing RC Buildings in Turkey Utilizing Ambient Vibration Records." Journal of Earthquake Engineering 12, sup2 (May 14, 2008): 140–50. http://dx.doi.org/10.1080/13632460802013909.

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Ritta, Raul J., Julio C. Massa, and Guillermo D. Chiappero. "Processing of ambient vibration records for the estimation of the fundamental vibration period of soil deposits." IEEE Latin America Transactions 11, no. 1 (February 2013): 300–306. http://dx.doi.org/10.1109/tla.2013.6502820.

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Fu, Jian Bao, Ai Hua Liang, and Bin Bin Xu. "Comparative Analysis of Underwater Vibrating Compaction Technology and Compaction on Land." Advanced Materials Research 1030-1032 (September 2014): 740–43. http://dx.doi.org/10.4028/www.scientific.net/amr.1030-1032.740.

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In HongKong-Zhuhai-Macao bridge project, about 4.8 kilometers stone bed underwater should be compacted to make it smooth and remove the excess settlement. Vibrating compaction method would be used to tamp the stone layer with no dead angle in a short construction period. This paper theoretical studied on vibrating compaction technology of scattering-filling rubble stone layer. Vibrating compaction system and stone layer were simplified to a mechanical model and the vibration equation was established. According to an interpolation table, a fitting formula of equivalent damping was given. Through rigorous mathematical derivation, this paper gave mathematical expressions of the vibration displacement, the vibration velocity and compaction work on stone layer. Both compaction work on land and compaction work underwater could be calculated by these mathematical expressions. Lastly, through a set of field test parameters, comparative analysis between compaction work on land and compaction work underwater was carried out. The result shows that the weakening effect of water on compaction work is poor.

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Wang, Hao, Tianyou Tao, Tong Guo, Jian Li, and Aiqun Li. "Full-Scale Measurements and System Identification on Sutong Cable-Stayed Bridge during Typhoon Fung-Wong." Scientific World Journal 2014 (2014): 1–13. http://dx.doi.org/10.1155/2014/936832.

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The structural health monitoring system (SHMS) provides an effective tool to conduct full-scale measurements on existing bridges for essential research on bridge wind engineering. In July 2008, Typhoon Fung-Wong lashed China and hit Sutong cable-stayed bridge (SCB) in China. During typhoon period, full-scale measurements were conducted to record the wind data and the structural vibration responses were collected by the SHMS installed on SCB. Based on the statistical method and the spectral analysis technique, the measured data are analyzed to obtain the typical parameters and characteristics. Furthermore, this paper analyzed the measured structural vibration responses and indicated the vibration characteristics of the stay cable and the deck, the relationship between structural vibrations and wind speed, the comparison of upstream and downstream cable vibrations, the effectiveness of cable dampers, and so forth. Considering the significance of damping ratio in vibration mitigation, the modal damping ratios of the SCB are identified based on the Hilbert-Huang transform (HHT) combined with the random decrement technique (RDT). The analysis results can be used to validate the current dynamic characteristic analysis methods, buffeting calculation methods, and wind tunnel test results of the long-span cable-stayed bridges.

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Journal articles on the topic 'Vibration period'

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