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Vibration Mode Analysis For Control Algorithm Implementation In Gyroscope Development

Vibration Mode Analysis For Control Algorithm Implementation In Gyroscope Development

Groscope is a rotation sensing instrument in Inertial Navigation Systems (INS) [1]. Development of Coriolis Vibratory Gyroscope (CVG) delivers all the aerospace requirements like small in size, weight, power and high reliability [2]. CVG has rigidly fixed hemispherical shell, in which its resonant vibration mode called primary wave mode at a known amplitude (a) is excited [3]. Once the gyroscope rotates about its axis, the Coriolis forces acts on the vibrating HS generate a second standing wave on it [4], [7]. This Second wave mode receives energy from the primary wave. The rate of transfer of vibration energy on both the standing modes can be accounted in terms of changing amplitude and phase about the HS [4]. The major requirement in the CVG is to measure the frequency and standing wave profile on the HS. A Phase Locked Loop (PLL) control is used to follow the change in phase of vibration mode [5],[6] with temperature during the operation [8],[9]. The designed frequency of the HS is in the human audible frequency range (20 Hz to 20 KHz), a low cost frequency measurement method is proposed by using the high sensitive microphone compare to the expensive optical method by using laser vibrometer. The standing wave profile at nodes and anti- nodes locations along the phase relation between them is measured electronically through capacitor formation at a fixed locations around the HS [10]. This scheme of capacitive pickoff is used in pendulous accelerometers [11], where the pendulum is suspended between the two fixed electrodes. When the accelerometer experiences an external force, the pendulum moves in response to the force applied.

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Development of a micro extruder with vibration mode for microencapsulation of human keratinocytes in calcium alginate

Development of a micro extruder with vibration mode for microencapsulation of human keratinocytes in calcium alginate

The alginate microcapsules can simply be produced by dripping the sodium alginate solution into the sodium chloride solution. Simple dripping technique can be used to generate microcapsules of alginate but this technique produced microcapsules in the range of 1000 to 3000 µm which are too large for the cells to grow. It was reported that the optimum size of the microcapsules for the microtissues to grow should be less than 1000 µm. Furthermore, smaller size of capsules can provide better transportation of nutrients and oxygen, easier implantation and better mechanical strength [11, 16]. Extrusion technology with vibration mode for microencapsulation method had been developed. Some of the technologies used the laminar liquid jet break up by a superimposed vibration and others used the monocentric or concentric nozzle system for cell microencapsulation [7]. However, most of the method comes with some disadvantages such as high complexity, difficult to conduct and high maintenance [6].

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Axial Vibration Mode of Coupled Liquid-Structure- Gas System in a Rigid Cylindrical Container

Axial Vibration Mode of Coupled Liquid-Structure- Gas System in a Rigid Cylindrical Container

The effect of the plate position on the natural frequencies was observed and they found that the natural frequencies drastically decrease when the plate approaches the rigid cylindrical container’s bottom or top surface. In [2], Gorman et al. analysed the vibration of a circular disc backed by a cylindrical cavity containing gas. They had developed a theoretical method to calculate the natural frequencies of a vibrating circular plate in interaction with a closed volume of compressible fluid. The analysis was extended in [3], where the modal parameter such as modal energy of the interacting fluid-structure system is extracted. In [4], Gorman et al. analysed the vibration of a thin circular plate influenced by liquid-gas interaction in a cylindrical cavity. They once again, developed a theoretical method to calculate the natural frequencies of a system consists a cylindrical gas cavity axially bounded at the bottom end by a liquid and a thin elastics circular plate at the top end. In [5], Gorman et. al. described the characteristics of strongly coupled membrane- fluid column interaction by simplified mass-spring system model. The mass-spring model compared fairly well with the full coupled model. Rajalingham et al. [6] studied the vibration analysis of a circular membrane backed by cyindrical cavity using multimodal approach. The cavity- backed membrane was modeled as a dynamical system composed of two subsystems, and their modal receptance characteristics were used to study the system vibration.

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MODAL ANALYSIS OF A SUSPENSION FOR HARD DISC DRIVE

MODAL ANALYSIS OF A SUSPENSION FOR HARD DISC DRIVE

Abstract: - In the digital era as the demand of transfer rate and data densities in computer hard disk drives has increased faster rotational disk has been imposed. Unfortunately, airflow-induced vibration of the disk drive suspension becomes a major barrier to positioning the read-write head with sufficient precision. Due complicated shape of HDD suspension it becomes difficult to analysis using traditional method. Therefore FEA study was conducted to obtain the resonant frequencies and determine the vibration mode with large radial displacement of the HDD suspension. By identifying the true design features, the extended service life and long term stability is assured. In this present work with the help ANSYS (11.0), vibration characteristics and vibration frequency distributions, structural characteristics of the Hard disk drive (HDD) suspension using modal analysis is investigated .The results show that the resonant frequencies and determine the vibration mode with large radial displacement of the HDD suspension.

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Driving modes and material stability of a double membrane rheometer and density sensor

Driving modes and material stability of a double membrane rheometer and density sensor

The sensor is placed in a basin containing the test liquid be- tween two permanent magnets, which provide field strengths of up to 0.2 T, see Fig. 2c. Liquid laterally enters the gap between both membranes. The connection of the excitation paths, which determines the excited vibration mode, is con- figured by the connection wires. The excitation paths are con- nected to a function generator, where GPIB (General Purpose Interface Bus) controlled frequency sweeps with an ampli- tude of approximately 0.5 V are used to evaluate the fre- quency response of the membrane vibration. The induced read-out voltage is measured with a Stanford Research lock- in amplifier SR 830.

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Development of Deep Sea Resonant Sandwich Linear Ultrasonic Motor

Development of Deep Sea Resonant Sandwich Linear Ultrasonic Motor

A deep-sea resonant sandwich linear ultrasonic motor is proposed and de- signed. We determine the parameter of its structure by finite-element analysis. The piezoelectric actuator adopts compound vibration mode of fifth order bending vibration and second order longitudinal. The mode degeneracy of that is completed. We manufacture the prototype to measure the performance of it. We measure its vibration mode and resonant frequency. The velocity of prototype can reach 264.5 mm/s while the water pressure is 8 MPa and the voltage signal with frequency of 30.30 kHz and voltage amplitude of 150 V.

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Vibration Analysis of Flapping Wing Micro Air Vehicle Using Finite Element Methods

Vibration Analysis of Flapping Wing Micro Air Vehicle Using Finite Element Methods

Fig 4: In this figure second vibration mode shape is shown which is obtained through both software ANSYS and Matlab. Upper mode shape of this figure is the second vibration mode obtained in ANSYS at 2.74Hz and lower one is the same mode obtained in Matlab at 1.98 Hz. There is little frequency difference between the modes obtained from the two software. This difference can be minimized by refining the codes further as a future work

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Dynamic Identification of All-FRP Pultruded Structures

Dynamic Identification of All-FRP Pultruded Structures

It can be noticed that the first vibration mode of the two structures happens at the same frequency along Y axis (i.e. 1.48Hz for structure 1 and 1.49Hz for structure 2), while there is a variation of 5% along X axis (2.06Hz for structure 1 and 1.95Hz for structure 2). The second (3.49 Hz) and third mode shape (4.17 Hz) of structure 1 (low) correspond to torque vibration modes. Structure 2 shows a similar behavior, with second modal shape at 2.04 Hz; the third shape at 2.54 Hz and fourth at 6.15 Hz have a significant torque component. Except for the first mode, the independent behavior of the two structures can be seen.

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Study of Vibration Milling for Improving Surface Finish of Difficult-to-cut Materials

Study of Vibration Milling for Improving Surface Finish of Difficult-to-cut Materials

axial mode of the vibration milling tool. A combined application of numerical and experimental analysis has confirmed the validity of the proposed approach. An experimentally verified finite element model of the vibration milling tool was built on the basis of the actual tool prototype. Complex tool structure in the numerical model was reduced to a single pre- twisted cantilever, which was imposed with boundary conditions (clamping and excitation conditions) that accurately reproduce those of the actual vibration tool. The model was used to determine the resonance frequency of the axial vibration mode of cutters of two different lengths. Milling experiments demonstrated that excitation of the axial mode in the vibration milling tool leads to an appreciable reduction in the surface roughness of stainless steel and titanium workpieces. The application of qualitative and quantitative characterization methods revealed better surface quality in comparison to the conventional milling process: surfaces having one roughness grade lower finish were obtained. A statistical analysis of the collected roughness data allowed us to establish that the dynamic characteristics (excitation frequency) of the tool and machining method (with or without the assistance of high-frequency vibrations) have the largest effect on surface quality. The reported research results demonstrate that it is crucial to dynamically tailor the excitation frequency of the vibration cutting tool in order to generate the required vibration mode in the mill cutter and thereby achieve the most pronounced improvement in surface finish in difficult- to-cut materials.

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Vibration Control of Smart Structure Using Sliding Mode Control with Observer

Vibration Control of Smart Structure Using Sliding Mode Control with Observer

Different control techniques have been investigated in the control of smart structure. Abreu conducted experimental work for the vibration control of flexible beam by using piezoelectric sensors and actuators with Linear Quadratic Gaussian (LQG) controller [4]. There are many classical strategies that can be used when the mathematical model is available, for instance pole allocation and optimal control. However, if the model has uncertainties these methods are not indicated. There are many robust techniques in structural control literature. Li investigated two control strategies for robust vibration control of parameter uncertain systems [5]. Mayhan combined intelligent control and smart materials to produced an adaptive and robust controller to dampen the fundamental vibration mode of the system in the presence of modeling uncertainties [6]. Zhang et al. studied the active vibration control problem for the high-speed flexible mechanisms all of whose members were considered as flexible by using complex mode method and robust H ∞ control scheme [7-8]. Kawabe utilized neural networks (NN) theory for active control in a longitudinal cantilevered-beam system by simulation and experiment. It is found that fairly satisfactory active

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An Overview of Disarray in Vibration Analysis of Cracked Rectangular Cantilever Beam Supriya D. Sankpal Arun V. Bhosale

An Overview of Disarray in Vibration Analysis of Cracked Rectangular Cantilever Beam Supriya D. Sankpal Arun V. Bhosale

The presence of cracks in a structure is usually detected by adopting a linear approach through the monitoring of changes in its dynamic response features, such as natural frequencies and mode shapes. But these linear vibration procedures do not always come up to practical results because of their inherently low sensitivity to defects. Since a crack introduces non-linearities in the system, their use in damage detection merits to be investigated. With this aim the present paper is devoted to analyzing the peculiar features of the non-linear response of a cracked beam. The problem of a cantilever beam with an asymmetric edge crack subjected to a harmonic forcing at the tip is considered as a plane problem and is solved by using two-dimensional finite elements; the behaviour of the breathing crack is simulated as a frictionless contact problem. The modification of the response with respect to the linear one is outlined: in particular, excitation of sub- and super-harmonics, period doubling, and quasi-impulsive behaviour at crack interfaces are the main achievements. These response characteristics, strictly due to the presence of a crack, can be used in non-linear techniques of crack identification. [3]

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EVALUATION OF EIGEN VALUES AND EIGEN VECTORS FOR FREE VIBRATION ANALYSIS USING FINITE ELEMENT PROCEDURES

EVALUATION OF EIGEN VALUES AND EIGEN VECTORS FOR FREE VIBRATION ANALYSIS USING FINITE ELEMENT PROCEDURES

The literature of eigenproblems is quite large, both for theoretical aspects and numerical algorithms, and only a small fraction of it can be cited. Hughes T.J.R. [1], Bathe K. J. [2] and Kardestuncer H. [3] have written extensive discussions about eigenproblems in their Finite Element Books. Wilkinson J.H. [4] wrote a book about the algebraic eigenvalue problem in 1965. Bathe K. J. and Wilson E.L. [5] published a paper on solution methods for eigenvalue problems in structural mechanics in 1973. In 1980, Parlett B.N. [6] introduced the method for solution of the symmetric eigenvalue problem. In 1984, Jennings A. [7] wrote about eigenvalue methods for vibration analysis. Sehmi N.S. [8] gave large order structural eigenvalue techniques in 1989. Cheung Y.K. and Leung A.Y.T. [9]. published a book on finite element methods in dynamics in 1991 In 1994, Tichler V.A. and Venk ayya V.B. [10] evaluated eigenvalue routines for large scale applications. Bertolini A.F. [11] reviewed eigensolution procedures for linear dynamic finite element analysis in 1998.

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High Mode Vortex Induced Vibration (VIV)
Experiments on a Large Scale Riser

High Mode Vortex Induced Vibration (VIV) Experiments on a Large Scale Riser

In 1976 [1] tested 23.3 m segments of various cables with fixed ends held under constant tension in a uniform flow. They found that as the Strouhal frequency approached the cables natural frequency, the phenomena of lock-in occurred. The maximum Reynolds number tested was 6850, and maximum mode number achieved was 7. There were only 2 accelerom- eters used to measure model displacements. A second set of experiments were performed by [2] in 1983 at Reynolds up to 22 000, using the same apparatus, and results showed that the drag coefficient reached values larger than 3. Again, only the seventh mode was achieved, and only 7 pairs of accelerometers were used over the 23.3 m model length. Reference [3] hung a 267 m Kevlar cable over the side of a vessel and found that the vibration response of a long cable was essentially that of an infinite string and single mode lock-in was not observed in a shear current. Only 3 accelerometers were used to determine modal displacements and there were problems reading the in- flowing current correctly. Reference [4] conducted sheared current tests on an instrumented cable arranged horizontally across the width of a 17.7 m canal. The test cable was a 0.028 m diameter rubber hose with 6 pairs of accelerometers along the length and a maximum mode number of 11 was achieved. Reference [5] conducted large scale tests involving two composite fiberglass pipes, 61 m and 122 m long, and 0.033 m in diameter. Twenty-four tri-axial accelerometers were spaced evenly along the length of the model and the maximum Reynolds number was approximately 34,000. The authors reported cross-flow flow excitation of up to the 25th mode.

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Health Monitoring Of Plate Structure Using Piezo Electric Patches And Curvature Mode Shape

Health Monitoring Of Plate Structure Using Piezo Electric Patches And Curvature Mode Shape

structure while in-service is preferred which is generally called Structural Health Monitoring (SHM). The dynamics-based damage detection is an effective method due to its simplicity of implementation and ability of acquiring both the global and the local information of the structure. The development of real- time, in-service structural health monitoring and damage detection techniques using smart material has recently attracted a large number of academic and industrial researchers. Application of a combination of two different damage detection techniques such as electromechanical coupling property of piezoelectric material and tracking the changes in the frequency response function data is shown in [1]. [2] Has presented the method which uses pairs of piezoelectric sensors bonded on both sides of a structure executing flexural oscillations in order to determine the changes in the strain distribution due to the presence of a crack. The advantage of using PZT sensors is that by passing a voltage in the PZT elements, strains are induced, even in the absence of external forces [3]. Experimental PZT based damage detection in steel bridge components is investigated [4]. A comprehensive survey of various vibrations based damage detection methods including curvature mode shape is presented in [5].A curvature mode shape based damage detection in composite structure is shown in [6]. The curvature mode is shown to be an excellent parameter in damage detection of structure while in case that certain curvature mode curve cannot show existence of damage. A curvature mode changing rate (CMCR) method for the damage detection is shown in [7]. In this study the effective combined utilization of Piezo Electric patches and Curvature mode shape for vibration based structural health monitoring is explored. It is not only detecting the damage but to estimate the damage location and severity.

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Suppressing Vibration In A Plate Using Particle Swarm Optimization

Suppressing Vibration In A Plate Using Particle Swarm Optimization

In the current work, the particle swarm optimization technique is employed for the vibration control of the (FGM) plate. PSO is a population-based stochastic search algorithm. When analytical approaches either do not apply or do not guarantee a global solution for nonlinear systems, stochastic search algorithms may provide a promising alternative to these traditional approaches. PSO is a relatively new stochastic optimization technique. It was first introduced by Kennedy and Eberhart [12]. The algorithm is theoretically simple and computationally

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Ultrafast 2D-IR and optical Kerr effect spectroscopy reveal the impact of duplex melting on the structural dynamics of DNA

Ultrafast 2D-IR and optical Kerr effect spectroscopy reveal the impact of duplex melting on the structural dynamics of DNA

It is however interesting that the loss of the B4 (ds-DNA) phonon band reaches a mid-point at a slightly higher temperature than the other measurements (330 ± 2K). Even accounting for the likely higher errors involved in deriving this value from a fit to the OKE data, this suggests that the B4 band persists even as the Watson-Crick interactions are being lost. Indeed, the ss-DNA phonon mode and the ds-DNA mode do not have the same midpoint. This observation is also visible in the previous reports of these bands on different oligomeric samples. 14 The origin of this effect is not clear but implies that

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Static and Vibration Analysis of Composite Beams Using Finite Element Methods

Static and Vibration Analysis of Composite Beams Using Finite Element Methods

mode, and the restoring force that tries to return that specific distortion of the body back to its equilibrium position. Each of these different ways of vibrating is known as a mode of vibration of the system. Each mode is assigned a number and the lowest frequency at which a system vibrates after all external loads are removed is assigned as mode 1 or fundamental mode. A mode of vibration is characterized by a modal frequency and a mode shape. Each mode is entirely independent of all other modes. Thus all modes have different frequencies and different mode shapes. In the study of vibration in engineering, the expected shape/curvature (or displacement) of a system at a particular mode due to vibration is the mode shape. Thus the mode shape always describes the time-to-time curvature of the system under vibration where the magnitude of the curvature continuously changes. The mode shape depends on two factors:

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The Research on Breaker Fault Status Parameter Classification of Improved Particle Swarm Optimization

The Research on Breaker Fault Status Parameter Classification of Improved Particle Swarm Optimization

Abstract. In order to improve the mechanical structure of the type of fault resolution precision high voltage circuit breaker spring mechanism, the paper analyzes the characteristics of the circuit breaker and the combination of mechanical vibration signal PSO algorithm (PSO) SVM parameter optimization method proposed collaborative dynamic acceleration constant inertia weight particle swarm optimization (WCPSO) optimization support vector machine (SVM) analysis breaker fault classification parameters and kernel function parameters. The vibration signal circuit breaker empirical mode decomposition, the total intrinsic mode components through energy analysis to obtain the required fault feature vectors and support vector machine as input, the use of dynamic acceleration constant synergy inertia weight PSO support vector machines penalty factor C and radial basis kernel function parameters  optimize the fault feature vector signal input test samples aft er SVM training sample trained optimized for fault classification, fault status classification.

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Development of a Complex Examination Device for QST in Medical Institutions

Development of a Complex Examination Device for QST in Medical Institutions

Sensory Testing (QST) while also reducing the workload of testers but without placing burden on subjects is a challenge. Several QST devices have been proposed thus far. Most notably, a pencil-type thermal aesthesiometer (Yufu Itonaga) for a temperature sensation testing device, and Vibration II (Sensortek) for a vibratory sensation testing device were developed, and the utility of these devices has been proven [2]. However, the devices invented thus far are all for use in single sensory tests, and our investigation indicates that there is no such device that integrates more than one sensory test.

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Modal analysis of concrete bridge decks subjected to free vibration

Modal analysis of concrete bridge decks subjected to free vibration

damage reported is not significant, the potential danger caused by the tremor should be a concern for the owners and authorities of landmark structures including bridges and buildings. The determination of baseline dynamic measurement or vibration signature of our structures should be made for their health monitoring. The after effects of loadings and earthquake forces can be detected on the structures using dynamic analysis and more research is required to study the application of vibration techniques for structural health monitoring.

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