Vibration Of Coupled System Research Articles

Analyze on a Coupled Beam Vibration System by FEM (II): Case Study

From the article of Analyze on a coupled beam vibration system by FEM (I): theory, equation of motion of the beam system with attachments is established by conventional finite element method, and some parameters, such as natural frequencies, associated mode shapes, are obtained. The mode localization and frequency loci veering phenomena of a weakly coupled beam system with multiple spring-mass systems are investigated. Studies show that for weakly coupled beam system with attachments, the mode localization and loci veering will occur once there is a disorder in the system.

Analyze on a Coupled Beam Vibration System by FEM (I): Theory

An approach based on finite element analysis is presented to analyze the free vibration of coupled beams with spring-mass attachments. The equation of motion of the beam system with attachments is established by conventional finite element method. The natural frequencies and the associated mode shapes are obtained from the generalized eigenvalue problem. It is found that the results from the proposed method agree well with those from analytical methods in the literature.

Modified Method of Semi-Analytical Transition Matrix on the Analysis of a Coupled Vibration System

The coupled bending-extensional in-plane vibration of a rotating curved beam is considered. The dynamic system is governed by two coupled differential equations and six boundary conditions. The conventional method of transition matrix is usually used to solve the system composed of one nth order differential equation and n boundary conditions. In this study, the system of a rotating curved beam is different from that of the conventional one. The modified method of a semi-analytical transition matrix is developed to study this system. Finally, several physical observations about the rotating curved beam are manifested.

Edge Detection Technology and its Application in the Model Test of Vehicle Bridge Coupled Vibration

At present, point sensors are mainly used in the measurement of the vehicle and bridge coupled vibration system. And only limited points of the system are measured. Test results can not be compared with calculated and analyzed results in the full field of the system. In the model test of the vehicle bridge vibration, test video is captured with a camera, each frame of the video is processed by the sub-pixel edge detection techniques to identify the deformation of the beam at each time, and the time history of the vibration response at each point of the beam. The model test results are compared with the calculated results of the vehicle bridge coupled vibration system. It is shown in the comparison that the beam deformation curves of both the test and analysis at each time are agreed quite good, and the time history responses of each point of the beam are also in good agreement. It means that the application of the video detection techniques in the vehicle and bridge coupled vibration model test is successful. Taking into account the advantages of the full field high density measurement and the synchronized measurement of the moving vehicle and bridge, further research and extension on the video detection technology are necessary.

Influence Analysis of Cell Plate Length to Slab Track Vertical Dynamic Response

A vehicle-track-subgrade coupling vibration system model was proposed to analysis the influence of cell plate length to slab track vertical dynamic response. The model was built with finite element method, rail was modeled as space beam element, both track plate and base plate were modeled as shell element, the vertical connections between rail, slab and subgrade were modeled as spring-damper element. The results show that with the cell plate length increases, the vertical vibration displacement of rail, track plate and base plate have decreasing tendency; the vertical vibration acceleration of rail has increasing tendency; the vertical vibration acceleration of track plate and base plate have decreasing tendency.

Study on the Maglev vehicle–guideway coupling vibration system

An innovative control approach for a Maglev system, including a new structure of the Maglev line and a novel levitation control method, is proposed in order to solve the problem of vehicle–guideway coupling vibration. Compared with a traditional Maglev line, the magnetic tracks in the new line are divided into smaller pieces to allow decoupling of the levitation magnets from the flexible supporting beams (steel or concrete beams). The vibration states of the magnetic tracks are introduced into the control system by the state observer, and a controller is designed using the full state feedback method. The effects of various parameters on the stability of the system are investigated. Also, a hardware-in-loop test rig is built to verify the feasibility of the scheme. The following conclusions are drawn based on the obtained results: in the new system, the magnet is dual-decoupled from the carbody and the supporting beam; the relative position between the magnet and the supporting beam exerts a negligible effect on the responses of the track and magnet, this makes it feasible to obtain all the vibration states of the track and the magnet using a state observer; an increase in the mass of the track is conducive to the stability of the system and a low pad stiffness value produces a faster decay ratio of the vibration of the supporting beam; the system’s stability margin is improved as the damping ratio of the supporting beam increases.

Simulation on Hydraulic-Mechanical Coupling Vibration of Cold Strip Rolling Mill Vertical System

Based on vibration problems of a six roller cold rolling mill, hydraulic-machinery coupling vibration system dynamic model of the 2180mm 4-stand tandem cold rolling mills was built integrated the software of MATLAB and ADAMS and simulated. The simulation result was consistent with that of the field test data revealed by rolling mill vibration. Through the comparison of the vertical systems motion displacement, velocity, acceleration under the different work condition, coupling vibration causes and evolution mechanism was analyzed, that had practical value to further control mill motor behavior.

Comparison of dispersive relation of the oil well with that of the fluid cylinder and the hollow in solid

Acoustical well logging is a widely used technique in oil fields to investigate the formation outside wells and the quality of wells. The knowledge of the acoustical behavior of the wells is important to the technique and has been widely studied. The wells are usually modeled as a fluid filled cylindrical borehole in an infinite solid medium. This structure with an infinite section, sometimes called as open waveguide, is more difficult to study than the typical acoustical waveguide with finite section and free or rigid boundaries. In this presentation the well is studied as a coupled vibration system consisted of the fluid cylinder inside the well and the solid formation outside the well. The dispersive relations of 3 systems, i.e., the circular fluid cylinder with rigid boundary, the circular hollow in solid medium and the fluid filled borehole in solid, are numerically calculated and compared.

Vibration Analysis and Optimal Design in Hydraulic Leveling System

In the process of launching, some launch bearing platforms will bear large impact force, thus causing severe vibration of the platform. There exists coupling relationship between this kind of vibration and the hydraulic system. In this paper, we established the vibration model according to the coupling vibration system in bearing platform and hydraulic system, and realized decoupling. Then we derived the vibration controlling equation and transfer function of coupling vibration between bearing platform and hydraulic system. Further more, we simulate the actual situation in software Simulink, and it gave vibration response curves under different parameters. In this way, it provides basis for reducing platform vibration.

Dynamics Analysis and Simulation for Fluid-Structure Coupled Vibration of Liquid Container

The analysis process for the linear coupled vibration of a circular container and its inner liquid often uses FEM method. An equation set which contained the fluid node pressure and the structure node displacement was formed, based on these equations, in this paper, a new equation set which has a smaller dimension and symmetrical form is obtained by the method of model reduction and coordinate symmetrization. By solving the boundary value problems of equivalent Laplace formulas, the additional masses matrix, additional stiffness matrix and coupling matrix which have effect from fluid to structure are gained. The example of the modal analysis for liquid container demonstrates that this method presented in this paper can get the modal frequency accurately and rapidly in fluid-structure coupled vibration system and other similar engineering realm.

The Study on Bridge Coupled Vibration System Analysis Model

On the base of modal synthesis theory, the self-compiling vehicle-bridge coupling vibration analysis program was used to analyze the vehicle dynamic response and passing vehicle riding comfort of cable-stayed bridge. Compared with the impact of different factors on vehicle riding comfort, this method provides a useful theoretical reference to correlated evaluation research and management maintenance. The influence of driving speed on comfort is not obvious. The research makes reference to correlated project evaluation in procedure and method.

Study on Influence of the Truss Bridge’s Nature Frequency by Added Masses

Due to the role of the vehicle, the large-span bridge’s frequency which is according to the bridge monitoring data is actually the vibration frequency of the vehicle-bridge coupled vibration system, but not the bridge’s natural frequency. This paper gets formulation of the added mass and the beam’s natural frequency according to the added mass of the beam’s vibration equation; and the formulation is tested by experiments and numerical simulation of a large-span steel truss bridge model. Result shows that added masses which have the fixed location are linearly proportional to changing values of the bridge’s nature frequency.

Influence of Material Properties on Modal Characteristics for Fluid-Structure Coupled Vibration System

The analysis processing for the linear coupled vibration of a flume and its inner fluid often uses FEM method. An equation set which contained the fluid node pressure and the structure node displacement is formed, based on this equation, reduction form and symmetry form is used to get the same modal frequency. Computers can calculate out the frequency more rapidly by a smaller control equation. According to the frequency comparison of different fluid-structure coupled vibration system with different materials, this paper draws some conclusions on the influence of material properties on modal characteristics for fluid-structure coupled vibration system. It can give a reference to select the material in practical engineer.

Simply Supported Box Girder Bridge Vibration Control with MR-TMD

MR-TMD is a new type of semi-active control device which combines with Tuned Mass Damper (TMD) and a Magnetorheological (MR) Damper. Taking German ICE3 high-speed railway train through 32meters simply supported box girder bridge for example, a dynamical model of Train-Bridge coupling vibration system is established by considering track irregularities. The relations between the bridge vibration and track irregularities with dampers are studied and the effects of vibration control with TMD and MR-TMD on the bridge are comparatively analyzed. The results show that the effects of track irregularities on vertical displacement of the bridge are relatively small, but on vibration acceleration are relatively large. As the train speed increases, the effects of track irregularities on the vibration acceleration is lager. As the track irregularities increase, the accelerations are greater. MR-TMD is able to inhibit vibration of bridge effectively, and has a wider control range and frequency bandwidth.

Impact Effect on Bridge in Model of Vehicle-bridge Coupled Vibration System

AbstractThe bridge and vehicle were treated as two separated sub-systems, the FEM model of three vehicle-bridge vibration were established based on software ANSYS. The dynamic response of vehicle-bridge coupled vibration system was solved by separated iterative algorithm with consideration of the deck roughness and compatibility conditions of the contact points. The fast inverse Fourier transform and trigonometric series iteration were used to generate 5 grades of deck roughness and their derivative velocity terms. The vehicle-bridge coupled vibration of a simple supported beam bridge was simulated numerically to find out the influence of vehicle model, road roughness and the velocity of moving vehicle on the impact effect of bridge. The result indicates that (1) the impact effects of bridge with variant vehicle models differ greatly; (2) the influence of road roughness is more significant than that of the velocity of moving vehicle, and the displacement impact effect is larger than the internal force imp...

Analysis Coupling Vibration Characteristic of HVAS Droplets Based on Wave-Like Disturbance

Characteristics of vibration molten metal droplets are decisive importance to performance of high velocity arc sprayed coating, it is hardly that detected the dynamic action of liquid droplets owing to the limitation of experimental technique. The gas fluid-liquid droplet coupling vibration system of equations were established based on wave-like disturbance, the governing equation for fastest-growing wave number is derived. The agreement of predicted fastest-growing wave number and data of Bradley, which has the deviation within the±2% limits,indicares that the gas fluid-liquid droplet coupling vibration system of equations is effective. By the use of the coupling vibration system of equations, the effects of gas velocity, gas type and molten metal type to vibration characteristics of HVAS droplets is researched. The results show that selected N2gas sprayed and increasing the gas velocity would be raise adhesive strength of the spraying coating, and provides theoretical evidence for choice of spraying materials and control in HVAS.

Comparison of Vertical Model and Spatial Model for Vehicle-Track-Bridge Coupling Vibration System

In this paper, models for vertical and spatial coupling vibration of vehicle-track-bridge system are established separately. The track vertical irregularity sample in time domain is established by power spectrum density and taken as the exciting source to analyze the coupling vibration of vehicle-track-bridge system of two models. The advantages and disadvantages and applicability of the vertical vibration model and the spatial vibration model are analyzed by comparing the vertical vibration responses of the two models under excitation with same level of track vertical irregularity.

Research on Dynamic Characteristics of Steel Bridge Deck Thin Paving

Basing on the coupled vibration theory, dynamic characteristics of steel bridge deck thin paving were investigated. Interaction model and coupled vibration partial differential equation were derived for the coupled vibration system of vehicle and bridge-deck-paving. The results obtained from the finite element analysis were compared with those from the field test, and in general, a good agreement was achieved. Effects of load lateral distribution and road roughness and surface crack and cohesive layer condition on the dynamic amplification factor (DAF) were studied. The results show that adding epoxy asphalt as a sub coat can reduce the dynamic amplification factors obviously, which would be designed as the cohesive layer of steel deck thin paving.

11809 励振される基礎上における剛体系のロッキングに関する研究(OS5 運動と制御(2),オーガナイズドセッション)

The purpose of this study is to formulate a motion of rigid bodies system with unilateral contact problems by applying techniques of multibody dynamics and to analyze the issue of rocking conditions of the rigid bodies with slide contact or collision. The system is a coupled vibration system composed of three rigid bodies elastically supported by excited foundation. The differential algebraic equation is solved by the augmented formulation with Lagrange multipliers, using generalized coordinates and non-generalized surface parameters that describe the contact point. The influences of rocking mode and slip on the rocking motion are discussed.

Analysis of dynamic characteristic and structure optimisation for hybrid machine tool

A new method that the exciting vibration test is simulated to analyse the dynamic characteristic of hybrid machine tool is proposed. The principle of exciting vibration test on dynamic characteristic is researched, and the skeleton and design process of swept sine vibration test is also given. In order to obtain accurate simulation results, the rigid?flexible coupling system model of hybrid machine tool is built in ADAMS software, which forms the exciting vibration simulation model. The exciting force is loaded on the coupling vibration system and brings displacement response, and then the curves of displacement response are obtained. According to the simulation results, the weak parts are effectively optimised and the simulation is carried out again on the optimised structure; then the simulation results are ideal and the deformation of weak parts is also reduced. Therefore, the simulation method can effectively improve the dynamic characteristic of hybrid machine tool.