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Zeitschriftenartikel zum Thema "Vibration period"

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Ryazancev, V., M. Gerasimov und 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, Nr. 5 (18.05.2021): 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 und 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, Nr. 4 (09.10.2018): 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, und 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, Nr. 2 (02.05.2019): 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 (Juli 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, Nr. 3 (07.08.2020): 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 und 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 und 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 und I. V. MOLODTSOVA. „RADIATIVE ACTIVITY OF MAGNETIC WHITE DWARF UNDERGOING LORENTZ-FORCE-DRIVEN TORSIONAL VIBRATIONS“. Modern Physics Letters A 26, Nr. 05 (20.02.2011): 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 und Chao Liu. „Numerical Analysis of Coupled Lateral and Torsional Vibrations of a Vertical Unbalanced Rotor“. Applied Mechanics and Materials 20-23 (Januar 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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Yakimova, Natalya L., Vladimir A. Pankov, Aleksandr V. Lizarev, Viktor S. Rukavishnikov, Marina V. Kuleshova, Elena V. Katamanova, Evgeny A. Titov und Dina V. Rusanova. „Neurophysiological and morphological effects in the post-exposure vibration period during experimental modeling“. Russian Journal of Occupational Health and Industrial Ecology, Nr. 5 (31.05.2019): 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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Dissertationen zum Thema "Vibration period"

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Dominguez, Morales Martha. „Fundamental period of vibration for reinforced concrete buildings“. Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0018/MQ58450.pdf.

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Young, Kelly Christine. „An Investigation of the Fundamental Period of Vibration of Irregular Steel Structures“. The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1316473829.

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Ticona, A. M., M. A. Rosales und J. D. Orihuela. „Correction coefficients of distortion and vibration period for buildings due to soil-structure interaction“. OP Publishing Ltd, 2020. http://hdl.handle.net/10757/656571.

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The present research analyzed the influence of the soil structure interaction (SSI) in buildings, varying geotechnical parameters and height, considering 3 international codes. The responses obtained from the structures taking into account the SSI, were compared with the responses of fixed-base buildings, being the main control variables: the period and the drift. It was determined that the estimated range in which the period of the structure increases is from 30 to 98%, demonstrating the influence of considering soil flexibility. Due to the variability of the responses obtained, an adjustment factor is proposed to predict said amplification of the control variables, depending on the height of the building and the ground.
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Hafeez, Ghazanfarah. „Dynamic Characteristics of Light-frame Wood Buildings“. Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/36223.

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This research project deals with dynamic field testing of light-frame wood buildings with wood based shear walls. The primary objective of the investigation is to evaluate the code formula for estimating light wood frame building’s fundamental period, through intensive field testing and numerical modelling. The project also aims to propose an alternative simplified rational approach where applicable. The thesis provides insight to the ambient vibration testing procedures of light-frame wood buildings and explains the protocol adopted for the current research program. Ambient vibration (AV) field tests were conducted on several multi-storey wood and beam-and-post buildings in Canada. Modal parameters of measured buildings, such as natural frequency, mode shapes and equivalent structural damping were obtained from Frequency Domain (FD) analysis of ambient motion records. Experimental and numerical investigations were performed to evaluate the effect of non-structural components, and the connectivity between firewall-separated buildings, on dynamic properties of light-frame wood buildings. The study provides a reliable expression for building period estimate based on field testing and numerical modeling.
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Navrátilová, Martina. „Nelineární dynamická analýza konstrukce zatížena seismickými účinky“. Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2015. http://www.nusl.cz/ntk/nusl-227701.

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Diploma thesis compares the methods for the calculation of the response of structures with seismic loads. Linear and nonlinear analyses are used for the calculations. In the case of linear analysis response spectrum method is applied. For nonlinear analysis pushover method is used. These two methods are compared in programs AxisVM and RFEM on the examples of high-rise building and space frame.
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Sun, Xiangkun. „Elastic wave propagation in periodic structures through numerical and analytical homogenization techniques“. Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEC041/document.

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Dans ce travail, la méthode homogénéisation de multi-échelle, ainsi que diverses méthodes non homogénéisation, seront présentés pour étudier le comportement dynamique des structures périodiques. La méthode de multi-échelle commence par la séparation d'échelles. Dans ce cas, une échelle microscopique pour décrire le comportement local et une échelle macroscopique pour décrire le comportement global sont introduites. D'après la théorie de l'homogénéisation, la longueur d'onde est supposée grande, et la longueur de la cellule doit être beaucoup plus petite que la longueur caractéristique de la structure. Ainsi, le domaine d'homogénéisation est limité à la première zone de propagation. Le modèle d'homogénéisation traditionnel utilise des valeurs moyennes des éléments, mais le domaine de validité pratique est beaucoup plus petit que la première bande interdite. Alors, le développement de nouveaux modèles homogénéisés est beaucoup motivé par cet inconvénient. Par rapport au modèle d'homogénéisation traditionnel, équations d'ordre supérieur sont proposées pour fournir des modèles homogénéisation plus précises. Deux méthodes multi-échelles sont introduites: la méthode de développement asymptotique, et la méthode de l'homogénéisation des milieux périodiques discrètes (HMPD). Ces méthodes seront appliquées de façon séquentielle dans le cas d'onde longitudinale et le cas d'onde transversale. Les mêmes modèles d'ordre supérieur sont obtenus par les deux méthodes dans les deux cas. Ensuite, les modèles proposés sont validés en examinant la relation de dispersion et de la fonction de réponse fréquentielle. Des solutions analytiques et la méthode des ondes éléments finis(WFEM) sont utilisés pour donner les références. Des études paramétriques sont effectuées dans le cas infini, et deux différentes conditions aux limites sont prises en compte dans le cas fini. Ensuite, le HMPD et CWFEM sont utilisés pour étudier les vibrations longitudinales et transversales des structures réticulées dans le cas 1D et 2D. Le domaine de validité du HPDM est réévalué à l'aide de la fonction de propagation identifiée par le CWFEM. L'erreur relative au nombre d'onde obtenue par HPDM est illustré sur la fonction de la fréquence et le rapport d'échelle. Des études paramétriques sur l'épaisseur de la structure sont réalisées par la relation de dispersion. La dynamique des structures finies sont également étudiés en utilisant la HPDM et CWFEM
In this work, the multi-scale homogenization method, as well as various non homogenization methods, will be presented to study the dynamic behaviour of periodic structures. The multi-scale method starts with the scale-separation, which indicates a micro-scale to describe the local behaviour and a macro-scale to describe the global behaviour. According to the homogenization theory, the long-wave assumption is used, and the unit cell length should be much smaller than the characteristic length of the structure. Thus, the valid frequency range of homogenization is limited to the first propagating zone. The traditional homogenization model makes use of material properties mean values, but the practical validity range is far less than the first Bragg band gap. This deficiency motivated the development of new enriched homogenized models. Compared to traditional homogenization model, higher order homogenized wave equations are proposed to provide more accuracy homogenized models. Two multi-scale methods are introduced: the asymptotic expansion method, and the homogenization of periodic discrete media method (HPDM). These methods will be applied sequentially in longitudinal wave cases in bi-periodic rods and flexural wave cases in bi-periodic beams. Same higher order models are obtained by the two methods in both cases. Then, the proposed models are validated by investigating the dispersion relation and the frequency response function. Analytical solutions and wave finite element method (WFEM) are used as references. Parametric studies are carried out in the infinite case while two different boundary conditions are considered in the finite case. Afterwards, the HPDM and the CWFEM are employed to study the longitudinal and transverse vibrations of framed structures in 1D case and 2D case. The valid frequency range of the HPDM is re-evaluated using the wave propagation feature identified by the CWFEM. The relative error of the wavenumber by HPDM compared to CWFEM is illustrated in the function of frequency and scale ratio. Parametric studies on the thickness of the structure is carried out through the dispersion relation. The dynamics of finite structures are also investigated using the HPDM and CWFEM
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石田, 幸男, Yukio ISHIDA, 剛志 井上, Tsuyoshi INOUE, 軍. 劉, Jun LIU, 昭宏 鈴木 und Akihiro SUZUKI. „重力と非線形ばね特性の作用を受ける偏平軸の振動 (内部共振の影響)“. 日本機械学会, 2001. http://hdl.handle.net/2237/9052.

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Bao, Bin. „Distributed, broadband vibration control devices using nonlinear approaches“. Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI086/document.

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L’amélioration du confort des usagers ainsi que l’augmentation du niveau de sécurité des structures requièrent le développement de techniques permettant de limiter efficacement les vibrations. Dans cette optique, les travaux exposés ici proposent le développement et l’analyse de méthodes de contrôle vibratoire pour des structures de faibles dimensions et utilisant peu d’énergie. Afin de satisfaire à ces deux critères, il est ici proposé d’utiliser des éléments piézoélectriques électriquement interfacés de manière non-linéaire et périodiquement distribués sur la structure-cible à contrôler. Ainsi, l’approche proposée permet de bénéficier à la fois des avantages des techniques de contrôle non-linéaires appliquées aux matériaux intelligents de type piézoélectrique, offrant des performances remarquables tout en étant peu consommatrices d’énergie, avec ceux des structures périodiques exhibant des bandes fréquentielles interdites présentant de fortes atténuations de la propagation d’onde. Plus particulièrement, ce mémoire s’intéresse à différentes architectures d’interconnexion des interfaces électriques non-linéaires permettant un bon compromis entre la bande fréquentielle contrôlée et les performances en termes d’atténuation des vibrations. Ainsi, trois architectures principales sont proposées, allant de structures totalement périodiques, tant au niveau mécanique qu’électrique (interconnexions), à des structures présentant un certain degré d’apériodicité sur le plan électrique (entrelacement), impactant ainsi la propagation de l’onde acoustique en élargissant la bande de contrôle, pour enfin proposer une architecture hybride entre interconnexion et entrelacement conduisant à des systèmes large bande performants
For ameliorating vibration reduction systems in engineering applications, miscellaneous vibration control methods, including vibration damping systems, have been developed in recent years. As one of intelligent vibration damping systems, nonlinear electronic damping system using smart materials (e.g., piezoelectric materials), is more likely to achieve multimodal vibration control. With the development of meta-structures (a structure based upon metamaterial concepts), electronic vibration damping shunts, such as linear resonant damping or negative capacitance shunts, have been introduced and integrated abundantly in the electromechanical meta-structure design for wave attenuation and vibration reduction control. Herein, semi-passive Synchronized Switch Damping on the Inductor (SSDI) technique (which belongs to nonlinear electronic damping techniques), is combined with smart meta-structure (also called smart periodic structure) concept for broadband wave attenuation and vibration reduction control, especially for low frequency applications. More precisely, smart periodic structure with nonlinear SSDI electrical networks is investigated from the following four aspects, including three new techniques for limiting vibrations: First, in order to dispose of a tool allowing the evaluation of the proposed approaches, previous finite element (FE) modeling methods for piezoelectric beam structures are summarized and a new voltage-based FE modeling method, based on Timoshenko beam theory, is proposed for investigating smart beam structure with complex interconnected electrical networks; then, the first developed technique lies in smart periodic structure with nonlinear SSDI interconnected electrical networks, which involves wave propagation interaction between continuous mechanical and continuous nonlinear electrical media; the second proposed topology lies in smart periodic structures with nonlinear SSDI interleaved / Tri-interleaved electrical networks involving wave propagation interaction between the continuous mechanical medium and the discrete nonlinear electrical medium. Due to unique electrical interleaved configuration and nonlinear SSDI electrical features, electrical irregularities are induced and simultaneously mechanical irregularities are also generated within an investigated periodic cell; the last architecture consists in smart periodic structures with SSDI multilevel interleaved-interconnected electrical networks, involving wave propagation interaction between the continuous mechanical medium and the multilevel continuous nonlinear electrical medium. Compared with the SSDI interconnected case, more resonant-type band gaps in the primitive pass bands of purely mechanical periodic structures can be induced, and the number of such band-gaps are closely related to the interconnection / interleaved level. Finally, the main works and perspectives of the thesis are summarized in the last chapter
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Rodrigues, Cunha Leandro. „Robust bandgaps for vibration control in periodic structures“. Thesis, Bourgogne Franche-Comté, 2017. http://www.theses.fr/2017UBFCD060.

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Dans cette thèse, une méthodologie simple pour trouver des bandes interdites robustes est présentée. Quatre cellules unitaires différentes sont utilisées comme exemples numériques pour des modèles infinis et finis. Les deux premiers sont liés aux zones d'atténuation créées pour les ondes longitudinales en utilisant des cellules unitaires de masse et ressort et de barres. La méthode Matrice de Transfert est utilisée pour modéliser la cellule unitaire. Avec cette méthode, il est possible d'obtenir les réponses en fréquence, en utilisant une méthode spectrale, et des constantes de dispersion, en résolvant un problème a valeur propre. Les paramètres physiques et géométriques les plus influents sont déterminés en effectuant une analyse de sensibilité aux dérivées partielles et aux différences finies à travers un modèle infini. Dans ce cas, pour le deuxième exemple, la section de la demi-cellule est considérée comme une variable stochastique, représentée par une fonction densité de probabilité pour une analyse probabiliste. Le troisième exemple concerne les bandes interdites pour les ondes de flexion utilisant des cellules unitaires de poutres. Dans ce cas, la méthode habituelle de Matrice de Transfert ne peut pas être utilisée pour obtenir une réponse de structures finies en basse fréquence en raison de la présence de matrices mal conditionnées. Par conséquent, une méthode récursive est utilisée pour éviter la multiplication de matrices. Une analyse expérimentale est également réalisée pour ce cas, mais considérant que la longueur de la moitié des cellules unitaire comme incertaine. Le dernier exemple est un treillis périodique considérée avec et sans propriétés intelligentes. La cellule unitaire de cette structure en treillis peut avoir des membres passifs et actifs. À cause de la complexité de ce type de cellule, la méthode des éléments finis est utilisée. Cependant, ce type de structure ne présente pas de ruptures d'impédance suffisamment fortes pour ouvrir des bandes interdites même avec la présence de sous-structures répétitives. En vertu de cela, huit scénarios sont étudiés en considérant l'introduction de masse concentrée dans les articulations et les actionneurs piézoélectriques dans les circuits shunt résonants qui sont considérés comme stochastiques pour des cas spécifiques. À la fin, les résonances internes sont analysées à l'aide d'un modèle plus précis. Pour chaque modèle de structure, une simulation de Monte Carlo avec Latin Hypercube est effectuée, les distinctions entre les zones d'atténuation incertaines correspondantes pour les modèles finis et infinis sont exposées et la relation avec les modes localisés est clarifiée. Ces résultats suggèrent que les modèles finis ont une bande interdite plus large que les modèles infinis en considérant les incertitudes. En d'autres termes, les incertitudes entre les cellules voisines se compensent et les structures finies sont naturellement plus robustes. Enfin, l'effet de l'augmentation du niveau d'incertitude, en faisant varier un coefficient stochastique, est analysé et le concept de bande interdite robuste est présenté
In this thesis, a simple methodology to find robust bandgaps is presented. Four different periodic structures are used as numerical examples for infinite and finite models. The first two are related to attenuation zones created for longitudinal waves using spring-mass and stepped rod unit cells. The Transfer Matrix method is used to model the unit cell. With this method, it is possible to obtain the frequency responses, using a spectral method, and dispersion constants, solving an eigenvalue prob-lem. The most influential physical and geometrical parameters are determined by performing partial derivative and finite difference sensitivity analysis through an infinite model. Therein, for the second example, the cross-section area of half-cell is considered as a stochastic variable represented by a probability density function with specific deviation properties for a probabilistic analysis. The third example concerns the bandgaps for flexural waves using stepped beams unit cells. For this case, the classical Transfer Matrix method cannot be used to obtain finite structures response in low frequency because of the presence of ill-conditioned matrices. Therefore, a recursive method termed Translation Matrix, which avoid matrix multiplication, is used and the corresponding probabilistic analysis is per-formed using the half-cell thickness as a random variable. An experimental analysis is also performed for this case, but considering half-cell length as uncertain. The last example is a periodic truss that is considered with and without smart components. The unit cell of this lattice structure can present pas-sive and active members. As long as the type of unit cell is more complex, the finite element method is used. However, this kind of structure does not have impedance mismatches strong enough to open bandgaps although the presence of repetitive substructures. In virtue of this, eight scenarios are inves-tigated considering the introduction of concentrated mass on joints and piezoelectric actuators in reso-nant shunt circuit which are considered as stochastic for specific cases. For each structure model, a Monte Carlo Simulation with Latin Hypercube sampling is carried out, the distinctions between the corresponding uncertain attenuation zones for finite and infinite models are exposed and the relation with localized modes is clarified. These results lead to conclude that the finite models present a larger stop zone considering stochastic parameters than infinite models. In other words, the uncertainties be-tween neighbors’ cells compensate each other and the finite structures is naturally more robust. Final-ly, the effect of increasing the uncertainty level, by varying a stochastic coefficient, is analyzed and the concept of robust band gap is presented
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Ben, Brahim Nadia. „Approche multiéchelle pour le comportement vibratoire des structures avec un défaut de rigidité“. Phd thesis, Université Nice Sophia Antipolis, 2014. http://tel.archives-ouvertes.fr/tel-01066795.

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Nous considérons un système mécanique en vibration non linéaire, pour lequel nous fournissons une solution approchée par l'utilisation des développements multiples échelles; nous proposons d'abord une étude avec double échelles puis avec triple échelles où nous comparons les deux approches. Une preuve rigoureuse de ces développements a été faite. L'étude de la stabilité de la solution est nécessaire pour montrer la convergence au voisinage de la résonance. Un lien entre l'amplitude de la réponse vibratoire et la fréquence du système en vibration libre a été mis en évidence.
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Bücher zum Thema "Vibration period"

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Mei, C. Component mode synthesis and large deflection vibration of complex structures: Final report for the period ended January 31, 1987. [Washington, DC: National Aeronautics and Space Administration, 1987.

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Britcher, Colin P. Large angle magnetic suspension test fixture: Final report for the period ended October 31, 1995. Norfolk, Va: Old Dominion University Research Foundation, 1995.

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Barbieri, Enrique. Momentum management in redundant manipulators for vibration suppression: Final report, NASA research grant NAG-1-1270 : report period June 1, 1992 - August 31, 1993. [Washington, D.C: National Aeronautics and Space Administration, 1993.

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Britcher, Colin P. Large angle magnetic suspension test fixture: Progress report for the period November 1, 1995 through May 1, 1996. Norfolk, Va: Dept. of Aerospace Engineering, Dept. of Mechanical Engineering, College of Engineering & Technology, Old Dominion University, 1996.

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Britcher, Colin P. Large angle magnetic suspension test fixture: Progress report for the period November 1, 1992 to May 31, 1993. Norfolk, Va: Dept. of Mechanical Engineering & Mechanics, College of Engineering & Technology, Old Dominion University, 1993.

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Britcher, Colin P. Large angle magnetic suspension test fixture: Final report for the period 11-1-95 thru 10-31-96. [Washington, D.C: National Aeronautics and Space Administration, 1997.

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Meirovitch, Leonard. A progress report on identification and control of structures in space: NASA research grant NAG-1-225, covering the period July 1 - June 31, 1985. Blacksburg, Va: Virginia Pollytechnic Institute and State University , Engineering Science and Mechanics Dept., 1985.

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Meirovitch, Leonard. A progress report on identification and control of structures in space: NASA research grant NAG-1-225, covering the period January 1 - June 30, 1985. [Washington, D.C.?: National Aeronautics and Space Administration?], 1985.

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Pierre, Christophe. Localized free and forced vibrations of nearly periodic disordered structures. New York: American Institute of Aeronautics and Astronautics, 1987.

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Heinbockel, J. H. Nozzle flow with vibrational nonequilibrium: Final report for the period ended August 31, 1995. Norfolk, Va: Old Dominion University Research Foundation, Dept. of Mathematics & Statistics, College of Sciences, 1995.

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Buchteile zum Thema "Vibration period"

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Charney, Finley A. „Period of Vibration“. In Seismic Loads, 115–22. Reston, VA: American Society of Civil Engineers, 2015. http://dx.doi.org/10.1061/9780784413524.ch17.

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Soni, Prabhat K., Prakash Sangamnerkar und S. K. Dubey. „Fundamental Time Period of Vibration in Seismic Analysis“. In Lecture Notes in Civil Engineering, 679–89. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-0890-5_56.

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Manyin, Hu, Liu Yujing, Yin Qi, Liu Zhong und Gao Xianglin. „Research on Vibration Period Optimization of Electrostatic Precipitator“. In Electrostatic Precipitation, 94–97. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-540-89251-9_19.

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Roy, Anuja, Atanu Sahu und Debasish Bandyopadhyay. „A Novel Sloshing Damper for Vibration Control of Short Period Structures“. In Lecture Notes in Civil Engineering, 323–30. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-8138-0_26.

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Pandey, Dhirendra Kumar, und Sudib Kumar Mishra. „Modified Tuned Liquid Damper for Vibration Control of Short Period Structures“. In Lecture Notes in Civil Engineering, 257–68. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-15-9976-7_24.

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Kawamura, Shozo, Tetsuhiko Owa, Tomohiko Ise und Masami Matsubara. „Proposition of Isolation Table Considering the Long-Period Earthquake Ground Motion (Method of Changing Natural Frequency of Isolation System with Additional Spring)“. In Vibration Engineering for a Sustainable Future, 245–53. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-48153-7_32.

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Soni, Prabhat Kumar, S. K. Dubey und Prakash Sangamnerkar. „Effect of Slab Thickness on Period of the Vibration of Reinforced Concrete Building“. In Lecture Notes in Civil Engineering, 353–61. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-5235-9_26.

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Zou, Hongbo, Dakai Liang, Jie Zeng, Kun Li und Yifei Zhou. „A Fiber Bragg Grating Vibration Interrogation System Based on a Cascaded Long-Period Fiber Grating“. In Communications in Computer and Information Science, 211–19. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-23226-8_28.

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Del Pedro, M., und P. Pahud. „Periodic Steady State“. In Vibration Mechanics, 80–97. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-011-3514-6_5.

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Jara, Jose M., Bertha A. Olmos und Guillermo Martínez. „Strengthening and Retrofitting of Motín de Oro II Bridge in Mexico“. In Case Studies on Conservation and Seismic Strengthening/Retrofitting of Existing Structures, 193–209. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2020. http://dx.doi.org/10.2749/cs002.193.

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This chapter presents the studies conducted to retrofit an existing bridge in a seismic prone area of Mexico. The Motín de Oro II Bridge was built in the 1970s with a continuous box girder superstructure and wall-type substructure. From the 1970s to nowadays, the design truck loads in Mexico have been substantially incremented and many bridges built in that period have required to be evaluated and, in some cases, rehabilitated and retrofitted. Firstly, the study presents the results of visual inspections of all parts of the bridge and a description of the preliminary studies conducted to determine the material properties, to evaluate the river flow characteristics and to calculate the scour depth. Secondly, the chapter discusses the initial structural analyses of the bridge subjected to the original gravitational and seismic loads and to the current loads before the intervention. These analyses allow to select the structural elements that require to be retrofitted and the best strategy to follow. Finally, the study presents results of the numerical retrofitted model and the experimental assessment of the dynamic properties based on ambient vibration measurements. Additionally, the scour protection and the general construction procedure are also described.
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Konferenzberichte zum Thema "Vibration period"

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Takeuchi, Makoto, Satoshi Tanaka, Shingo Tekuramori, Atsushi Wada und Nobuaki Takahashi. „Mechanical vibration sensing using cascaded long period fiber grating“. In 2013 Conference on Lasers and Electro-Optics Pacific Rim (CLEO-PR). IEEE, 2013. http://dx.doi.org/10.1109/cleopr.2013.6600331.

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Somatomo, Hiroyuki, Satoshi Tanaka und Nobuaki Takahashi. „Vibration sensing of solid using long-period fiber grating“. In 19th International Conference on Optical Fibre Sensors, herausgegeben von David D. Sampson. SPIE, 2008. http://dx.doi.org/10.1117/12.785961.

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Pi, Jun, und Xiangji Bu. „Analysis of Full-Period and Non-full-Period Sampling of Vibration Signal for Engine Rotors“. In 2015 International Conference on Industrial Technology and Management Science. Paris, France: Atlantis Press, 2015. http://dx.doi.org/10.2991/itms-15.2015.121.

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Black, Jared L. „Using Vibration Measurements to Assess Structural Integrity“. In ASME 2009 28th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/omae2009-79144.

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Structural vibration monitoring can aid in assessing offshore platform structural integrity. The method utilizes topside acceleration measurements to detect the platform’s natural periods of vibration; the periods depend only on platform weights (mass) and resistance (stiffness). If the platform’s natural period increases over time, in the absence of a change in mass, it can indicate a loss of structural integrity. The vibration survey utilizes a portable monitoring system, which includes sensitive low frequency accelerometers. The above water monitoring provides information on the below water structural integrity; the method is very low cost when compared to diver or ROV surveys. Examples of structural monitoring surveys are presented, including the following: verification that a platform remained fit for purpose despite having its foundation disturbed by a shallow gas release, two cases of using surveys to confirm jacket stiffness recovery following repairs of structural damage caused by Gulf of Mexico hurricanes and evaluation of a minimal platform after a heavy compressor was installed. The development of a natural period database is reviewed. The database, covering 95 platforms in Asian waters, was developed to reduce inspection costs and aid in life extension reviews, as well as providing quick integrity assessments should a tropical cyclone cross the production area.
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Lu, ShuQing. „The ANSYS Analysis of Predominant Period Varication under the Site Vibration“. In 2009 Second International Conference on Information and Computing Science. IEEE, 2009. http://dx.doi.org/10.1109/icic.2009.344.

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Neyman, Lyudmila A., Vladimir Yu Neyman und Andrei S. Shabanov. „Vibration dynamics of an electromagnetic drive with a half-period rectifier“. In 2017 18th International Conference of Young Specialists on Micro/Nanotechnologies and Electron Devices (EDM). IEEE, 2017. http://dx.doi.org/10.1109/edm.2017.7981805.

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Yu, Bo, und Albert C. J. Luo. „Periodic Motion in a Nonlinear Vibration Isolator Under Harmonic Excitation“. In ASME 2017 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/imece2017-71032.

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In this paper, periodic motions of a periodically forced oscillator with a nonlinear isolator are studied through generalized harmonic balanced method. Both symmetric and asymmetric period-1 motions are obtained. Stability and bifurcation of the periodic motions are determined through eigenvalue analysis. Numerical illustrations of both symmetric and asymmetric are given. From the harmonic amplitude spectrums, the harmonic effects on periodic motions are determined, and the corresponding accuracy of approximate analytical solutions can be observed.
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Zhang, Zijun, Chunjian Hua und Chaofan Wang. „Study on Fatigue Fracture Period of Metal Pipes under Compound Vibration Loading“. In 2020 39th Chinese Control Conference (CCC). IEEE, 2020. http://dx.doi.org/10.23919/ccc50068.2020.9188490.

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„Evaluation of Measurement Accuracy of the MEMS Accelerometer for Long Period and Large Amplitude Vibration“. In Structural Health Monitoring. Materials Research Forum LLC, 2021. http://dx.doi.org/10.21741/9781644901311-27.

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Abstract. Health monitoring systems are used to assess building damage immediately after an earthquake and have become widely utilized in Japan. For example, the system developed by the authors has been installed in more than 60 buildings since 2014. Such systems mostly rely on accelerometers to estimate the building performance. Recently, Micro electro mechanical system (MEMS) accelerometers have been increasingly applied for such uses due to their economic advantages. However, MEMS accelerometers are known to have relatively low measurement accuracy for certain frequency band excitations compared to servo type accelerometers. Past research has been undertaken to test their measurement accuracy, however, few studies review their performance under long period and large amplitude seismic motions. Evaluation of measurement accuracy in such conditions is essential since the system is also installed in tall buildings and isolated buildings with relatively long natural periods. Therefore, this study evaluates the measurement accuracy of the MEMS accelerometer under long period and large amplitude vibration based on the results of shake table testing.
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Shind, Yui, Yasuhiro Tsutsum, Takahiro Has, Masaharu Ohash, Yuji Miyosh und Hirokazu Kubot. „Vibration Monitoring Based on the Polarization Dependent Loss of Long Period Fiber Gratings“. In 2018 23rd Opto-Electronics and Communications Conference (OECC). IEEE, 2018. http://dx.doi.org/10.1109/oecc.2018.8730141.

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Berichte der Organisationen zum Thema "Vibration period"

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Wang, Kon-Well. Piezoelectric Tailoring with Enhanced Electromechanical Coupling for Concurrent Vibration Control of Mistuned Periodic Structures. Fort Belvoir, VA: Defense Technical Information Center, Dezember 2006. http://dx.doi.org/10.21236/ada471779.

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Xi, X. Vibrational and Electronic Properties of Fullerene and Carbon-Based Clustors. Final Reports for period July 1, 1997 - June 30, 2001. Office of Scientific and Technical Information (OSTI), November 2002. http://dx.doi.org/10.2172/833761.

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Quinn, Meghan. Geotechnical effects on fiber optic distributed acoustic sensing performance. Engineer Research and Development Center (U.S.), Juli 2021. http://dx.doi.org/10.21079/11681/41325.

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Distributed Acoustic Sensing (DAS) is a fiber optic sensing system that is used for vibration monitoring. At a minimum, DAS is composed of a fiber optic cable and an optic analyzer called an interrogator. The oil and gas industry has used DAS for over a decade to monitor infrastructure such as pipelines for leaks, and in recent years changes in DAS performance over time have been observed for DAS arrays that are buried in the ground. This dissertation investigates the effect that soil type, soil temperature, soil moisture, time in-situ, and vehicle loading have on DAS performance for fiber optic cables buried in soil. This was accomplished through a field testing program involving two newly installed DAS arrays. For the first installation, a new portion of DAS array was added to an existing DAS array installed a decade prior. The new portion of the DAS array was installed in four different soil types: native fill, sand, gravel, and an excavatable flowable fill. Soil moisture and temperature sensors were buried adjacent to the fiber optic cable to monitor seasonal environmental changes over time. Periodic impact testing was performed at set locations along the DAS array for over one year. A second, temporary DAS array was installed to test the effect of vehicle loading on DAS performance. Signal to Noise Ratio (SNR) of the DAS response was used for all the tests to evaluate the system performance. The results of the impact testing program indicated that the portions of the array in gravel performed more consistently over time. Changes in soil moisture or soil temperature did not appear to affect DAS performance. The results also indicated that time DAS performance does change somewhat over time. Performance variance increased in new portions of array in all material types through time. The SNR in portions of the DAS array in native silty sand material dropped slightly, while the SNR in portions of the array in sand fill and flowable fill material decreased significantly over time. This significant change in performance occurred while testing halted from March 2020 to August 2020 due to the Covid-19 pandemic. These significant changes in performance were observed in the new portion of test bed, while the performance of the prior installation remained consistent. It may be that, after some time in-situ, SNR in a DAS array will reach a steady state. Though it is unfortunate that testing was on pause while changes in DAS performance developed, the observed changes emphasize the potential of DAS to be used for infrastructure change-detection monitoring. In the temporary test bed, increasing vehicle loads were observed to increase DAS performance, although there was considerable variability in the measured SNR. The significant variation in DAS response is likely due to various industrial activities on-site and some disturbance to the array while on-boarding and off-boarding vehicles. The results of this experiment indicated that the presence of load on less than 10% of an array channel length may improve DAS performance. Overall, this dissertation provides guidance that can help inform the civil engineering community with respect to installation design recommendations related to DAS used for infrastructure monitoring.
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