Analysis Of Vibration Characteristics Research Articles

Analysis of motion and vibration characteristics of elastic composite cylindrical roller bearing

To investigate the motion characteristics and vibration characteristics of elastic composite cylindrical roller bearings (ECCRBs), a simulation model of the ECCRB is established in ABAQUS software. The influences of filling degrees and working conditions on motion characteristics of the ECCRB are compared, and the modal characteristics and harmonic response of the ECCRB are analyzed. Calculation results show that when the filling degree increases from 0% to 60%, there is a nonlinear relationship between the filling degree and the slip rate of cage, the natural frequency of each order decreases, and the vibration displacement of ECCRB increases under the excitation load; increasing the rotation speed and decreasing the radial load reasonably is beneficial to the motion stability of the ECCRB. At the same time, with the increase of the excitation load, the vibration displacement of the ECCRB increases. The analysis results can present some theoretical basis for the structural optimization of the ECCRB.

Analysis of Fluid-Structure Coupling Vibration Characteristics of Pipeline Transporting Bubbly Fluid Medium: With Application to Luxury Passenger Ship Life Area Pipeline

When pipelines are transporting bubbly fluid medium, due to the coalescence and breakage behaviours of the bubbles, the pressure distribution at the wall is not uniform and the structure response is more complex. The bubbly beverage pipeline in the life area of the luxury passenger ship is a typical scene of the pipeline transporting bubbly fluid medium. In this paper, the two-way fluid-structure coupling analysis is carried out on such a scene with the aid of ANSYS software and the PBM model is introduced to characterize the dynamic properties of bubbles. At the same time, the accuracy of this calculation method is verified by the scaling experiment. On this basis, the response of the pipeline under the excitation of bubbly fluid is calculated for different inlet velocities and gas volume fractions, and the effectiveness of common vibration damping measures is evaluated. The result shows that the addition of bubbles to the fluid medium has a significant effect on the distribution of the flow field in the pipeline during transport, and the vibration acceleration values of the pipe wall also increase significantly. This method enables accurate simulation of the vibration characteristics of bubbly fluid medium pipelines.

Horizontal dynamic modeling and vibration characteristic analysis for nonlinear coupling systems of high-speed elevators and guide rails

Horizontal dynamic modeling and vibration characteristic analysis for nonlinear coupling systems of high-speed elevators and guide rails

Mechanism analysis and experimental verification of the bulging vibration characteristic of a fluid-solid metamaterial

Most metamaterials consist of a solid medium, whereas research is lacking on fluid-solid metamaterials (FSMs). Water storage tanks in sponge cities can be considered periodic structures or FSMs and can be used for wave isolation. However, the wave propagation properties of FSMs are unclear. A finite element analysis model of metamaterials was established using COMSOL software based on the periodic theory. The dispersion curves, frequency response functions, and vibration modes of the FSMs were determined. Mechanism analysis of the bulging vibration and Bragg scattering characteristics of the FSMs was conducted, considering fluid-solid coupling and the vibration modes. A periodic water container (PWC) sample was used as the FSM, and dynamic tests were carried out to verify its inhibitory effect on the P-wave propagation. The results showed that the proposed FSM could excite the bulging modes, blocking the propagation of the elastic longitudinal waves and converting the energy of the structure into the bending energy of the wall plates. It could attenuate the elastic longitudinal waves in two extremely low-frequency ranges. The water improved the vibration damping capacity of the FSM, reducing the lower bound frequency of the initial Bragg scattering attenuation zone and enlarging the attenuation range. This study provides a new concept for designing water storage devices to reduce environmental vibrations at certain frequencies. The new device can have a broad impact in advanced vibration reduction measure.

Comparative Analysis of CFRP and Steel Vibration Characteristics of Machine Tools Components

Vibration of manufacturing machine parts can be reduced by applying CFRP to precision machines. Recently, the use of 3D printers in manufacturing has increased. However, there are few studies on the vibration characteristics of 3D printed composite materials. The objective of this study is to analyze the vibration reduction effect of a 3D printed composite material used as a CFRP chuck adapter. The existing chuck adapter is made of steel. In this study, the vibration values for three types of CFRP, steel, and CFRP with steel chuck adapters are compared. The products were rotated at 10, 500, and 1000 rpm, and the vibration velocity and displacement were calculated as an average value after repeating each measurement 5 times. Vibration velocity was improved by up to 64% and displacement by up to 31.1%. These results can be usefully applied to other mechanical parts requiring vibration damping.

Numerical analysis and experimental research of vibration and noise characteristics of oil-immersed power transformers

Oil-immersed power transformers play a prominent role in power grid system, and its vibration and noise influence the operation of the power grid. In this paper, an electromagnetic–mechanical-acoustic coupled three-dimensional finite element method of oil-immersed transformer is established. On this basis, according to a noise and vibration experiment of product-level oil-immersed power transformer, it not only proves the effectiveness of the calculation model, but also explores the influences of the radiating grilles and input voltage on the vibration and noise characteristics of the oil immersion transformer quantitatively. Research shows that the main frequency components of transformer vibration and noise focus on 100 Hz and its higher and integer multiple frequencies. The errors of total vibration acceleration level and overall sound pressure levels between the simulation results and test results do not exceed 3 dB, which verify the effectiveness of the numerical method.

Vibration characteristics analysis of fluid-conveying pipes concurrently subjected to base excitation and pulsation excitation

Previous studies mostly concentrated on the vibration characteristics of the fluid-conveying pipe (FCP) under a single excitation, which is insufficient to address the requirements of FCP vibration analysis under a complex load environment. Meanwhile, the aero-engine pipes may be affected by both base and pulsation excitations during operation, which could result in more complicated vibration behaviors. To solve the vibration response of FCPs concurrently subjected to base excitation and pulsation excitation, a modified transfer matrix model is proposed in this study. The proposed model overcomes the shortcoming that the traditional transfer matrix model (TMM) can only be utilized to analyze the frequency response of FCP under point excitation or pulsation excitation. By modifying the pipe’s governing equation, the base excitation is introduced into the whole pipe segment in the form of the external excitation vector. The proposed model is validated by comparing the collected vibration signals and simulation results of a straight FCP and L-shaped FCP under base excitation and pulsation excitation. Then, the study is further extended to the parallel fluid-conveying pipes (PFCPs), and the influences of base excitation amplitude, flow velocity, pressure, coupling stiffness, and dual clamp damping on the vibration characteristics of PFCPs are analyzed. This work can provide an efficient and general solution for vibration prediction of complex fluid-conveying pipes subjected to base and pulsation excitations in engineering.

Analysis of Stator Vibration Characteristics in Synchronous Generators Considering Inclined Static Air Gap Eccentricity

This paper mainly focuses on the impact of inclined static air gap eccentricity (ISAGE) on the electromagnetic characteristics and mechanical performances (vibration, deformation, strain and stress). Considering different ISAGE fault types in the theoretical and finite element analysis (FEA) model of synchronous generators, the effects of intersection position of the rotor center axis and stator center axis, rotor inclined angle, and the combination of the previous two fault types on MFD, phase current and radial magnetic pulling per unit area (MPPUA) are analyzed and compared. Then, based on the stator model used uniformly in three physical fields, the harmonic response and mechanical response are investigated with loads imported by the electromagnetic field. Finally, the stator radial vibration measurement experiments are carried out to verify the results obtained by theoretical analysis and FEA. It is shown that ISAGE will considerably enlarge the fluctuation of MPPUA and intensify the radial vibration of the stator, especially at the 2nd harmonic. The probability of failure at tooth tip and inner slot wall of the stator will increase.

Analysis of Vibration Characteristics of Single-Axle Tractors with Gasoline and Diesel Engine

Highlights Operators of single-axle tractors are exposed to high levels of hand-arm vibrations. A single-axle tractor with a gasoline engine produces lower vibrations than a tractor with a diesel engine. The daily working time with the single-axle tractor should be limited to protect the operators. If daily vibration exposure is not limited, hand-arm vibration syndrome may occur in a relatively short time. Abstract. Single-axle tractors are often the only source of mechanical power for agricultural activities on small farms, but operators are exposed to high levels of hand-arm vibrations transmitted from the handles. These vibrations can cause hand-arm vibration syndrome (HAVS), which includes vascular, neurological, and musculoskeletal disorders. The aim of this paper was to evaluate and compare the vibrations transmitted to the operator’s hands from the handles of two single-axle tractors (with gasoline and diesel engines). The vibration levels were measured at engine idling mode and at full load during soil tillage. The frequency-weighted acceleration values during soil tillage were 11.76, 2.90, and 6.16 m s-2 for the single-axle tractor with gasoline engine, while the values for the single-axle tractor with diesel engine were 22.47, 6.83, and 7.95 m s-2 in the X-, Y-, and Z-axes, respectively. As expected, significantly lower acceleration values were measured for both tractors at engine idling mode. The daily vibration exposure of the operator of the single-axle tractor with gasoline engine was 9.02 m s-2, and at such exposure, hand-arm vibration syndrome will occur in 10% of the operators after 3.09 years. For the single-axle tractor with a diesel engine, the daily exposure was 16.86 m s-2, and hand-arm vibration syndrome will occur in 10% of the operators after only 1.59 years. The daily working time with a single-axle tractor should be limited to protect the operators, and work schedules should be arranged to include vibration-free periods. Keywords: Ergonomics, Exposure limits, Hand-arm vibrations, IC engine, Single-axle tractor.

Transient Torsional Vibration Characteristic Analysis and Active Suppression of PHEV with Planetary Coupled Transmission System during Mode Transition Process

Transient Torsional Vibration Characteristic Analysis and Active Suppression of PHEV with Planetary Coupled Transmission System during Mode Transition Process

Dynamic modeling and vibration characteristics analysis of parallel antenna

Abstract. Research on the vibration characteristics of the mechanical systems is a necessary step for the stable and reliable operation of high-end equipment. The 6 degrees of freedom parallel mechanism is proposed for the supporting mechanism of the antenna. First, the dynamic equations of the moving platform and branch of the mechanism are established. The closed-form dynamics of the mechanism are derived based on the Newton–Euler method. In addition, the vibration equation of the parallel antenna is established based on the vibration theory, and the relationship between the natural frequency, displacement response, and vibration frequency is obtained. Afterward, the pitch and roll poses of a 1.8 m aperture antenna are developed based on a MATLAB software simulation. The actuation forces of parallel antenna under no-load and load conditions are simulated. Finally, the natural frequencies and vibration modes of the initial position and roll (20∘) are simulated based on the Adams software vibration analysis module. Furthermore, the relationship between the displacement response of the moving platform and the resonant frequency is studied based on the harmonic response analysis. The control strategy based on the dynamic model improves the control accuracy of parallel antenna. This research work provides a guarantee for the dynamic characteristics analysis and engineering application of parallel antenna.

Dynamic Modeling and Vibration Characteristics Analysis for the Helicopter Horizontal Tail Drive Shaft System with the Ballistic Impact Vertical Penetrating Damage

Dynamic Modeling and Vibration Characteristics Analysis for the Helicopter Horizontal Tail Drive Shaft System with the Ballistic Impact Vertical Penetrating Damage

Analysis of free vibration characteristics of porous rectangular plates with variable thickness

Analysis of free vibration characteristics of porous rectangular plates with variable thickness

Analysis and design optimization approach of vibration characteristics of an I shaped straight steel girder bridge

Bridges are subjected to environmental exposure like corrosion which may induce cracks. These cracks may cause change in natural frequency of bridge. The current study's goal is to explore the effect of crack on the vibration characteristics of bridge the design and modal analysis of bridge is conducted by ANSYS 21 simulation package. Two different designs of bridges are evaluated i.e. without crack and with crack.The effect of crack on natural frequency and mode shape is evaluated. The vibration characteristics of bridge structure changed with artificially induced transverse elliptical crack on girder.Techniques of optimization could help in determining the behaviour of the damage and extent to which it could be controlled via simulation technique without conducting tests on the actual model. Analysing the frequencies using ANSYS software, the validity of the presented numerical formulation is studied. Response spectrum methodology is used in studying the crack characteristic and optimization of crack variables. Sensitivity analysis showed the individual effect of each variable on the output parameters. Moreover, the response surface plots generated showed the peak and least deformation values of natural frequencies. Invaluable information which help practicing engineers better understand the vibration characteristics is provided.

Modal Analysis of Main Structure of Substation Post-switchgear

The main structure of the substation post-equipment is a typical wind-sensitive structure, which is high and flexible. In order to ensure the safety and stability of the structure, it is necessary to conduct a modal analysis of the main structure of the substation post equipment, which in turn provides a basis for the analysis of wind vibration characteristics of the structural system. This paper analyzes the self-oscillation frequency and vibration pattern of the main structure of a substation in Inner Mongolia based on ABAQUS, compares them with the measured wind response modal results to verify the reliability of the numerical simulation results and finds that the low-order natural frequency of the main structure of the substation pillar-type equipment is between 0-2 Hz, and the frequency in the opening state is lower than the state of closing soon.

Dynamic modelling and analysis of cracked gear system with tip relief based on proposed variable-angle deformation energy integration method

Due to ignoring the effects of the change of the tooth attachment position caused by the cracks, traditional time vary mesh stiffness (TVMS) calculation models and dynamic simulations for cracked gears will lose their precision in the body crack case. To address this shortcoming, a new analytical TVMS calculation model of cracked gear considering tip relief (TR) is developed based on a proposed variable-angle deformation energy integration method. On this basis, a dynamic model of the gear system for the analysis of fault vibration characteristics is established. The effectiveness and accuracy of the proposed TVMS calculation model are verified by the finite element method. A comprehensive investigation is finally carried out to reveal the effects of the parameters of TR, load and crack on the TVMS and dynamic characteristics of the cracked gears. The study results indicate that the proposed models can meet the accurate TVMS calculation and dynamic simulation for both the tooth- and body-cracked gears, and the influences of the tooth attachment position change caused by the crack cannot be ignored. This study could provide a systematic methodology and meaningful reference for the dynamic modelling, simulation and fault diagnosis of gear systems with crack failures.

Nonlinear dynamic and forced vibration characteristic analysis of sandwich panel with double-U auxetic core and GPLRC facing sheets embedded with piezoelectric layers

The aim of the present research is to investigate the nonlinear dynamic and forced vibration of a composite sandwich panel embedded with piezoelectric layers under thermo-harmonic loading. The panel consists of a double-U auxetic honeycomb core made of aluminum alloy and graphene platelet reinforced composite (GPLRC) skins at the top and bottom surfaces. According to Gibson’s formula, the effective material properties of facing sheets and double-V auxetic core are considered. The nonlinear equations are obtained by applying Hamilton’s principles via von Karman’s nonlinear theory and higher-order shear deformation theory (HSDT). The governing equations of motion are solved by employing the differential quadrature method (DQM) and homotopy perturbation method, respectively. The accuracy of the current results has been verified by comparison with others in the literature. Finally, the influence of different parameters such as applied voltage, magnetic potential, temperature rise, different boundary conditions, and geometric parameters of core on the nonlinear frequency-amplitude response of cylindrical panels are analyzed. The numerical results show negative effect of temperature increment, positive influence of ratio of thickness to inclined length, core thickness, amplitudes of segments, considerable effect of the magnetic potential as well as small effect of applied voltage on the nonlinear vibration of sandwich panel. Finally, the important findings of this research indicate that the magnetic potential, amplitude segment, and length to inclined cell rib length have significant effects on nonlinear dynamic deflection and frequencies-amplitude response. Based on the results of this article, designers can develop different parts of aircraft.

Prediction Method of Unsteady Flow Load of Compressor Stator under Working Condition Disturbance

Due to the complexity of the compressor operating conditions and the existence of various disturbances and unsteady effects in the flow field, the analysis of compressor stator vibration characteristics becomes particularly critical. The convolutional neural network model combined with a transient CFD method was introduced to solve the difficulty of analyzing the flow load of the compressor stator blade. This paper mainly focuses on two key points: the complex change of the aerodynamic load and the accurate prediction of the blade excitation. Considering the stator–rotor interference, the unsteady effects, and the variable working condition characteristics, the random disturbance analysis model of the flow field boundary was generated to simulate the unsteady flow excitation of the stator under complex working conditions. By establishing the neural network of boundary disturbance and flow excitation characteristics, the prediction model was trained and generated under the support of large-scale data. The most important role of the model was to establish the end-to-end data mapping between the disturbance condition and the aerodynamic load of the stator blade. The conclusions demonstrate that the introduction of an airflow disturbance is helpful to obtain the excitation characteristics of the stator under complex working conditions. The model established in this paper based on 1000 groups of disturbed working condition data can effectively predict the aerodynamic load of the blades under complex working conditions. In addition, the construction of the model is beneficial for saving a lot of computing resources, and the prediction accuracy also reaches a good level. The method presented in this paper provides a reference for the vibration analysis of the compressor stator.

Computational Investigation of Vibration Characteristics Analysis for Industrial Rotor

Abstract During the operation of a rotor, various types of vibrations appear in this mechanical system and often limit the performance and endanger the safety of the operation. Therefore, dynamic analysis is essential because precise knowledge of the vibration behaviour is essential to ensure proper operation. This article presents a set of scientific techniques for the modelling and simulation of rotor vibrations. To work out the equations of the vibratory movement of the rotor, we used the energy approach of Lagrange. To achieve this, a model with one blading wheel carried by a shaft supported by two hydrodynamic bearings is chosen basedon the characteristics of the rotor studied (Fan 280 cement draft fan). It is an arduous task to manually ascertain the analytical resolution of the differential equations that characterise the vibratory behaviour of the rotor. The numerical approach employing the finite element method, programmed on the ANSYS software, made it possible to perform the vibration analysis of the rotor. First, the FAN 280 cement draft fan rotor is modelled using SolidWorks 3D software and reverse design using the coordinate measuring machine (CMM) for the design of the fins. Then, the modal characteristics of the fan rotor model were analysed using the finite element analysis (FEA) software ANSYS Workbench. Also, to study the effect of blade wear on critical speeds, the Campbell diagram was obtained. Finally, harmonic analysis was performed to determine the amplitude of the rotor vortex at critical speeds obtained with and without blade wear.

Vibration characteristics analysis of a type of turbine disk-blade assembly system in the civil aero-engine

The coupled vibration in the turbine disk-blade system (TDS) is one of the main bottlenecks that hinder the further development of high-performance engines. To analyze the vibration of the TDS, three types of contact conditions, involving bonded, frictionless, or frictional were used to simulate the contact between the turbine disk and the blades. Three finite element analysis (FEA) models of a typical TDS based on the tenon structure were developed. The experimental system was developed and experimental modal analysis (EMA) was performed. According to the comparison between FEA and EMA results, the most accurate model is the frictional contact FEA model. The average error of the frictional contact FEA model is 1.42%, and the root mean square error is 0.75%. The working modes of the TDS at different speeds were calculated using the frictional contact FEA model. Meanwhile, based on the newly developed FEA model, it is found that the weak links in the TDS are the blades. This work can provide a theoretical basis for the TDS structure optimization and promote the development of high-quality aero-engines.