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1 Chapter 1 : Home - Linear and Nonlinear Dynamics and Vibrations Laboratory Get this from a library! Vibration, shock, damage, and identification of mechanical systems: presented at the ASME design technical conferences, 14th Biennial Conference on Mechanical Vibration and Noise, Albuquerque, New Mexico, September, Select this result for bulk action Vibration of Timoshenko beams using non-classical elasticity theories Authors: This paper presents a comparison among classical elasticity, nonlocal elasticity, and modified couple stress theories for free vibration analysis of Timoshenko beams. A study of the influence of rotary inertia and nonlocal parameters on fundamental and higher natural frequencies is carried out. The nonlocal natural frequencies are found to be lower than the classical ones, while the natural frequencies estimated by the modified couple stress theory are higher. The modified couple stress theory results depend on â the beam cross-sectional size while those of the nonlocal theory do not. Convergence of both non-classical theories to the classical theory is observed as the beam global dimension increases. Nonlocal elasticity theory, couple stress theory, Timoshenko beam, rotary inertia, free vibration DOI: Shock and Vibration, vol. Inerters have become a hot topic in recent years especially in vehicle, train, building suspension systems, etc. Eight different layouts of suspensions were analyzed with a quarter-car model in this paper. Dimensionless root mean square RMS responses of the sprung mass vertical acceleration, the suspension travel, and the tire deflection are derived which were used to evaluate the performance of the quarter-car model. The behaviour of semi-active suspensions with inerters using Groundhook, Skyhook, and Hybrid control â has been evaluated and compared to the performance of passive suspensions with inerters. Sensitivity analysis was applied to the development of a high performance semi-active suspension with an inerter. Numerical simulations indicate that a semi-active suspension with an inerter has much better performance than the passive suspension with an inerter, especially with the Hybrid control method, which has the best compromise between comfort and road holding quality. Ohmori, Hiroshi Article Type: Two dimensional boundary characteristic orthonormal polynomials are used in the Ritz method for the vibration analysis of clamped and simply-supported circular plates of varying thickness. In order to verify the validity, convergence and accuracy of the results, comparison studies are made against existing results for the special case of â linearly tapered thickness plates. Variations in frequencies for the first six normal modes of vibration and mode shapes for various taper parameters are presented. In this paper, an approach using observability and controllability grammian matrices is proposed to determine if structural damage has occurred together with an estimate of its location. The theory is outlined and simulations are carried out on a simple structure to demonstrate the method. Experimental tests were also carried out to demonstrate the validity of the approach using real signals. The dynamic properties of the structure are identified using the eigensystem realization algorithm ERA and a â reduced order state-space model of the system subsequently constructed. Either the observability or controllability grammians can then be used depending on the number of sensors available. It is shown that these are sensitive to both the degree and location of the damage and offer promise for structural health monitoring applications. The formulation and solution of the inverse problem of damage identification based on wave propagation approach are presented. Different damage scenarios for a bar are considered. Time history responses, obtained from pulse-echo synthetic experiments, are used to identify damage position, severity and shape. In order to account for noise corrupted data, different levels of signal to noise ratio â varying from 30 to 0 db â are introduced. In the identification process, different optimization methods are â investigated: It is shown that the damage identification procedure built on the wave propagation approach was successful, even for highly corrupted noisy data. Test case results are presented and a few comments on the advantages of deterministic and stochastic methods and their combination are also reported. Finally, an experimental validation of the sequential algebraic algorithm, used for modeling the direct problem, is presented. Structural damage identification, wave propagation in solids, particle swarm optimization, hybrid optimization method DOI: The Page 1

2 effectiveness and convenience of the method is illustrated in these examples. It will be shown that the solutions obtained with current method have a fabulous conformity with those achieved from time marching solution. HFAF is easy with powerful concepts and the high accuracy, so it can be found widely â applicable in vibrations, especially strong nonlinearity oscillatory problems. Ramadan, Khaled Article Type: This paper presents the transverse vibration of Bernoulli-Euler homogeneous isotropic damped beams with general boundary conditions. The beams are assumed to be subjected to a load moving at a uniform velocity. The damping characteristics of the beams are described in terms of fractional derivatives of arbitrary orders. In the analysis where initial conditions are assumed to be homogeneous, the Laplace transform cooperates with the decomposition method to obtain the analytical solution of the investigated problems. Subsequently, â curves are plotted to show the dynamic response of different beams under different sets of parameters including different orders of fractional derivatives. The curves reveal that the dynamic response increases as the order of fractional derivative increases. Furthermore, as the order of the fractional derivative increases the peak of the dynamic deflection shifts to the right, this yields that the smaller the order of the fractional derivative, the more oscillations the beam suffers. The results obtained in this paper closely match the results of papers in the literature review. Fractional damping, moving load, vibration, beams, fractional derivative DOI: Kumar, Yajuvindra Article Type: The free transverse vibrations of thin nonhomogeneous rectangular plates of variable thickness have been studied using boundary characteristic orthogonal polynomials in the Rayleigh-Ritz method. Gram-Schmidt process has been used to generate these orthogonal polynomials in two variables. The thickness variation is bidirectional and is the cartesian product of linear variations along two concurrent edges of the plate. Numerical results have been computed for four different combinations of clamped, simply supported and free edges. Effect of the nonhomogeneity and thickness variation with varying values of aspect ratio on the natural frequencies of vibration is illustrated for the first three modes of vibration. Three dimensional mode shapes for all the four boundary conditions have been presented. A comparison of results with those available in the literature has been made. The principal parametric resonance of two van der Pol oscillators under coupled position and velocity feedback control with time delay is investigated analytically and numerically on the assumption that only one of the two oscillators is parametrically excited and the feedback control is linear. The slow-flow equations are obtained by the averaging method and simplified by truncating the first term of Taylor expansions for those terms with time delay. It is found that nontrivial solutions corresponding â to periodic motions exist only for one oscillator if no feedback control is applied although the two oscillators are nonlinearly coupled. Based on Levenberg-Marquardt method, the effects of excitation and control parameters on the amplitude of periodic solutions of the system are graphically given. It can be seen that both of the two oscillators can be excited in periodic vibration with proper feedback. However, the amplitudes of the periodic vibrations are independent of the sign of feedback gains. In addition, the influence of time delay on the response of the system is periodic. In terms of numerical simulations, it is shown that both of the two oscillators can also have quasi-periodic motions, periodic motions about a new equilibrium position and other complex motions such as relaxation oscillation when feedback control is considered. Principal parametric resonance, coupled van der Pol oscillators, feedback control, time delay, bifurcation DOI: We present in this paper a novel and unified control approach that combines intelligent fuzzy logic methodology with predictive method for controlling chaotic vibration of a class of uncertain chaotic systems. The proposed controller can successfully stabilize the chaos and track the desired targets. The simulation results illustrate its effectiveness. Page 2

3 Chapter 2 : Shock and Vibration - Volume 19, issue 3 - Journals - IOS Press Vibration, Shock, Damage and Identification of Mechanical Systems [D. Carne, etc.] on theinnatdunvilla.com *FREE* shipping on qualifying offers. Proceedings of the 1st international modal analysis conference. Updating the mathematical model of a structure using vibration data. Journal of Vibration and Control, 11 12, The state of the art in analysis of cellular and voided slab bridges. Canadian Journal of Civil Engineering, 8 3, Methodology and Case Studies. Theory, Practice, and Application. Research Studies Press, Damage identification and health monitoring of structural and mechanical systems from changes in their vibration characteristics: Proceedings-spie the International Society for Optical Engineering. Proceedings of the International Modal Analysis Conference. Proceedings of Euromech international workshop: Past, Present, and Future. Applications to Structural Dynamics. Springer Science and Business Media, Midas Information Technology Co. Model updating in structural dynamics: Journal of Sound and Vibration, 2, Bridge deck analysis CRC Press Prentice Hall Pandey, A. Prentice-Hall, 1 Rytter, A. Proceedings of the 12th International Modal Analysis. All items in Spectrum are protected by copyright, with all rights reserved. Page 3

4 Chapter 3 : LDS shaker systems â Brüel & Kjà r Sound & Vibration Shock and Vibration is a peer-reviewed, Open Access journal that publishes original research articles as well as review articles on all aspects of shock and vibration, especially in relation to civil, mechanical, and aerospace engineering applications. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Damage detection and identification as well as continuous condition monitoring are one of the most important issues related to proper operation of machines and structural parts in order to ensure their structural integrity, safety, and desirable operational properties. In recent years, an exponential development of vibration-based methods for damage detection and identification as well as condition monitoring used for machines and structures has been observed. This development was possible for two main reasons: Both of these reasons influence modern trends related to vibration-based damage identification and condition monitoring in mechanical structures and components. This special issue is focused on recent attempts in development of vibration-based damage identification in mechanical structures and also homogeneous and inhomogeneous structures, especially stressing the latter such as advanced composites, and related issues connected with modal analysis and structural dynamic analysis. Moreover, the special issue covers damage identification and monitoring topics related to theoretical studies and numerical simulations as well as practical solutions, in particular in rotary machinery and vibration-generating devices, structural elements of heavy machinery and vehicles, etc. Thus, this special issue collects interdisciplinary approaches on vibration-based damage identification and condition monitoring, and it can be good motivation to consider and develop some innovative directions of research. All the trends and innovations in vibration-based damage identification and condition monitoring have attracted the attention to this special issue from the international researchers and scientists. This special issue has attracted 40 submissions from authors from all around the world; only 19 papers have been selected and included in this special issue on shock and vibration and vibration-based damage identification and condition monitoring in mechanical structures and components. The selection of the high-level papers was conducted as a rigorous peer-review process by the international, well-recognized experts in the appropriate fields presented in each paper. Thus, each manuscript has been evaluated as single, original work with the comparison with current state of art. The editors of the special issue would like to thank all authors of all submitted articles. More of the submitted papers were interesting and present original research. The first selection consisted in assessing compliance with the topic of special issue. The second stage of evaluation was based on originality and quality of the paper. The last editorial stage selected best papers to present wide range of research on vibration-based damage identification and condition monitoring in mechanical structures and components. Thus, even good papers could be rejected to ensure presentation of different areas. Selected papers present application of vibration and acoustics -based diagnostic and monitoring methods for different mechanical structures and materials. Other criteria of selection were to present novel approach and possibilities in signal processing and original research on application of new mathematical methods for the purpose of damage identification or structural health monitoring. Therefore, this special issue presents different approaches in vibration-based diagnostics, and it can indicate new areas or new application for further research. Conflicts of Interest The editors declare that they have no conflicts of interest. Page 4

5 Chapter 4 : ISO/TC - Mechanical vibration, shock and condition monitoring This paper provides an overview of methods to detect, locate, and characterize damage in structural and mechanical systems by examining changes in measured vibration response. Functions[ edit ] A logger comprises sensors such as accelerometers, storage media, a processor and power supply. The sensors measure and store shocks either as the entire waveform, summary data, or an indication of whether a threshold value was observed. Some devices have accelerometers built into the unit while others can use external accelerometers. The processor processes the measured data and saves it on the storage media together with the associated measurement times. This allows the measurement data to be retrieved after the measurements have been completed, either directly on the logger or via an interface to a computer. Some have an RFID interface. The shock and vibration data is either recorded continuously over a defined time period or on an event-driven basis where the recording of data is determined by certain criteria. Employing such an event-based measurement method allows the recording of specific shocks that exceed a critical length of time or strength. Some have wireless capability such as Bluetooth transmissions to smart phones. Such devices will not lose the data when the device is powered down. This also means that the measured data will remain stored in the event of a power failure. Overview of shock measurement[ edit ] Shocks and impacts are often described by the peak acceleration expressed in g-s sometimes called g-forces. The form of the shock pulse and particularly the pulse duration are equally important. For example, a short 1 ms g shock has little damage potential and is not usually of interest but a 20 ms g shock might be critical. Use of shock response spectrum analysis is also useful. The mounting location also affects the response of most shock detectors. A shock on a rigid item such as a sports helmet or a rigid package might respond to a field shock with a jagged shock pulse which, without proper filtering is difficult to characterize. A shock on a cushioned item usually has a smoother shock pulse. Shocks are vector quantities with the direction of the shock often being important to the item of interest. A shock data logger can be evaluated: Separately in a laboratory physical test, perhaps on an instrumented shock machine. Mounted to its intended item in a testing laboratory with controlled fixturing and controlled input shocks. In the field with uncontrolled and more highly variable input shocks. Use of proper test methods, calibration, and Verification and validation protocols are important for all phases of evaluation. Monitoring of goods in transit[ edit ] Shock loggers can be used to monitor fragile and valuable goods during transit and to measure the transportation shock and vibration environment. Some large items may have several shock sensors to measure different locations. The measured data reveals whether the goods in transit have been subjected to potentially damaging conditions. Based on this data, the options may be: If there have not been unusual shock or vibration continue to use the shipment as is, without special inspection If potentially damaging hazards have occurred, thoroughly inspect the shipment for damage or conduct extra calibration prior to use The consignee may choose to reject a shipment where sensors indicate severe handling The time of the damage, or GPS tracking, may be able to determine the location of the damaging shock or vibration to direct appropriate corrective action. Shock and vibration data from multiple replicate shipments can be used to Compare the shipment severity of different routings or of logistics providers. The shock handling data is often most useful converted from accelerations to drop heights or other means of quantifying the severity of impacts. Several means of statistical analysis of drops and impacts are available. Acceleration logger measuring vibrations on a tool carousel of a CNC lathe Among other applications, acceleration sensors are used to: Measure accelerations in motor vehicles, for example during the reconstruction of road accidents. Monitor machinery used on production lines that is sensitive to shocks or vibrations. Monitor and reduce wear in industrial plants and for increasing the performance of machines. Monitor trucks for excessive jolts [7] Measure vibrations in wind generators. Record input shocks and vibrations to humans [8] Record movement data for health management, patient monitoring. Animal monitoring of breathing, walking, standing, lying and sleeping behaviour. Measuring acceleration for avalanche emergency systems. Monitoring vibrations in data Page 5

6 centers for sensitive equipment [9] Measure impacts to sports helmets [10] [11] Determine the g-forces acting on people when riding rollercoasters. Establish accelerations for objects on conveyor belts. Chapter 5 : Shock and vibration data logger - Wikipedia Vibration, shock, damage, and identification of mechanical systems: presented at the ASME Design Technical Conferences - 14th Biennial Conference on Mechanical Vibration and Noise, Albuquerque, New Mexico, September, Page 6