Vibration Reduction Optimization Research Articles

Optimization analysis of vibration reduction for aeroengine multistage blade-disk system

In order to reduce the vibration localization of multistage blade-disk system of aeroengine compressor, the integral model and substructure model of multistage blade-disk system are established by using substructure modal synthesis method, and the dynamic characteristics of two models are analyzed and the accuracy of the substructure model is verified by comparison. Based on the substructure model, two optimization algorithms of the random wear mass and the snake optimization are proposed. The results show that the vibration amplitudes of the two models are in good agreement in the first 200 modes, and the substructure model meets the requirement of analysis accuracy. Both optimization algorithms can effectively reduce the degree of the vibration localization of the mistuned blade-disk system. The random wear mass algorithm can quickly reduce the amplitude of the blade. The snake optimization algorithm can find the global optimal solution with enough iterations. The results show that the maximum vibration amplitude and the vibration localization factor after optimization are reduced by 5.72 % and 12.0 % respectively by using the random wear mass algorithm, and that of 9.13 % and 16.7 % respectively by using the snake optimization algorithm. The analysis method presented in this paper takes into account the analysis efficiency and analysis precision, it can be used for dynamic analysis and vibration reduction optimization of large power machinery such as aeroengine and gas turbine, and provides a basis for further improving the reliability and service life of aircraft.

Damping Optimization Method of Combine Harvester Frame Undergoing Multi-Source Excitation

The complex mechanical system of a rice combine harvester not only has various excitation sources, but also, the vibration transmission path between each working device and the vibration contribution characteristics to the frame are not clear, so it is difficult to perform a reduction vibration design for the sharp vibration of the rice combine harvester frame. Therefore, based on the comparison and improvement of multiple classical transfer path analysis methods, this paper analyzed the vibration transfer characteristics and transfer characteristics of each harvester by the discrete time matrix method and operating path method. In the Experimental section, through the vibration characteristic experiment firstly, this paper obtained the power spectrum variation and the most needed optimized path in the transmission path of each device under each operating condition. Secondly, through frame simulation analysis under the exciting force, we obtained the vibration damping areas that needs to be optimized. Finally, the damping optimization experiment connected with the vibration characteristic experiment, and the excitation force simulation analysis was performed. The results of the damping optimization experiment displayed that the maximum change value of the vibration acceleration of the cutting table decreased from 7.862 m·s−2 to 3.522 m·s−2, decreasing by 55.2%, and the peak amplitude of the multipoint test in the cab was 5.4, 5.3, 1.7 and 2.0 μm, respectively, which was significantly reduced, so the optimization effect was significant. This study provides theoretical support for the vibration reduction optimization of a rice combine harvester frame.

Target-oriented inverse optimization design of phononic crystals with variable constraints for vibration attenuation

Previous research on phononic crystals (PnCs) design mostly focused on the maximum band gap (BG) between adjacent orders and could not optimize the desired target frequency based on actual engineering problems. In order to achieve an arbitrarily specified BG structure of PnCs near the target frequency, a new topology design method for PnCs is proposed using a special triangular lattice PnC as the object. In the genetic algorithm (GA) optimization framework, two variable constraint optimization strategies, fixed-step and adaptive, are proposed to form a variable constraint genetic algorithm (VC-GA), which enables the non gradient optimization process to be continuous and uninterrupted. This optimization model also divides optimization into two stages, which can search for target individuals and maximize BG under the constraints of the target BG. Combining the optimization model with the improved fast plane wave expansion method (IFPWEM) for optimizing the single and multi-objective BGs in the in-plane and out-of-plane modes, and the weight coefficient is introduced to broaden its scope of application. The effectiveness of the method is verified through experiments, and the vibration reduction optimization design is carried out within a specific frequency range for the engineering structure corrugated plate as an example.

An adaptive dual-Kriging method based on parameter sensitivity analysis and application to vibration reduction optimization of helicopter rotor test-bed

An adaptive dual-Kriging method based on parameter sensitivity analysis and application to vibration reduction optimization of helicopter rotor test-bed

Effect of novel phononic crystals vibration isolator on vibration reduction for floating slab track considering the random dynamical load of the vehicle

ABSTRACT The vibration caused by urban rail transit has led to numerous severe environmental issues. The floating slab track (FST) plays an important role in vibration control and noise reduction for rail transit. In this study, a novel phononic crystal vibration isolator (NPCVI) is developed based on the principle of local resonance to address the deficiencies in the low frequency vibration reduction of existing FST with steel spring vibration isolators (SSVI). The vibration equation of the NPCVI is derived and an analytical method for the dynamic interaction between vehicle, track, and tunnel is proposed. The pseudo excitation method (PEM) is introduced to solve the random vibration response of the vehicle-track-tunnel coupled system under the excitation of full-band track random irregularity. The numerical simulation results are compared with the field measurement results to verify the correctness of the solution model. The vibration reduction analysis of FST using NPCVI is conducted within a system dynamics framework, and a comparison is made between the performance of the conventional SSVI and the proposed NPCVI while a train is passing. The vibration reduction optimization effect of the NPCVI is evaluated using the vibration level (VL) of the tunnel structure. The results demonstrate that the NPCVI exhibits a superior band gap width as compared to that of the SSVI.

A High-Precision Super Element Used for the Parametric Finite Element Modeling and Vibration Reduction Optimization of the Pipeline System

A High-Precision Super Element Used for the Parametric Finite Element Modeling and Vibration Reduction Optimization of the Pipeline System

Simulation on Vibration Characteristics of Oil Tank of Flexible DC Transformer with Different Foundation

The transformer vibration and noise under the action of voltage and current is a serious problem to the equipment itself and the environment. In this paper, a newly designed and manufactured flexible DC transformer is considered. To reduce vibration and noise of the transformer through proper installation on the foundation, the vibration characteristics of the oil tank with different foundation designs are analysed. The numerical simulation model of the oil tank with two kinds of foundation is established based on the FEA. The convergence of the numerical model is verified through coarse and fine meshes. The vibration characteristics, including the natural frequencies, the modal shapes, and the harmonic responses, are revealed based on the simulation. The present results can provide a foundation of the vibration noise analysis and vibration reduction optimization of the transformer.

Fast Vibration Reduction Optimization Approach for Complex Thin-Walled Shells Accelerated by Global Proper Orthogonal Decomposition Reduced-Order Model

A fast vibration reduction optimization approach accelerated by the global proper orthogonal decomposition (POD) reduced-order model (ROM) is proposed, aiming at increasing the efficiency of frequency response analysis and vibration reduction optimization of complex thin-walled shells. At the offline stage, the global POD ROM is adaptively updated using the sample configurations generated by the CV (cross validation)–Voronoi sequence sampling method. In comparison to the traditional direct sampling method, the proposed approach achieves higher global prediction accuracy. At the online stage, the fast vibration reduction optimization is performed by combining the surrogate-based efficient global optimization (EGO) method and the proposed ROM. Two representative examples are carried out to verify the effectiveness and efficiency of the proposed approach, including examples of an aerospace S-shaped curved stiffened shell and a Payload Attach Fitting. The results indicate that the proposed approach achieves high prediction accuracy and efficiency through the verification by FOM and obtains better optimization ability over the direct optimization method based on FOM.

Analysis of Vibration Characteristics of Podded Propulsor Shafting Based on Analytical Method

Podded propulsors are widely used in warships and cruise ships, which have a higher requirement of vibrational and acoustic design. Therefore, studying vibration characteristics and the transmission mechanism of podded propulsor shafting is significant for reducing vibration and ensuring the safe operation of ships. This paper establishes a model of podded propulsor shafting by analytical method. The shafting is simplified to a heterogeneous variable cross-section beam, while bearings are seen as springs. The podded propulsor shafting has one radial-thrust hybrid bearing and one radial bearing. The excitations from the propeller and cabin are considered. The influences of bearing stiffness, bearing location, and excitation on vibration characteristics of shafting are analyzed. The main conclusions are as follows: Based on the analysis of the area that resonance frequency is sensitive to the change of bearing stiffness, the resonance frequencies of the shafting can be adjusted to the proper range. The large span between hybrid bearing and radial bearing leads to low stiffness of shafting and low resonances frequencies. Under radial excitations, the low vibration always occurs at the hybrid bearing, motor shafting, or propeller end of shafting. This research provides theoretical support for the design and optimization of vibration reduction of podded propulsor shafting.

Finite element modal analysis and experiment of rice transplanter chassis

The vibration problem during the operation of rice transplanters is the most common phenomenon. In order that the static and dynamic characteristics of the rice transplanter chassis can meet the requirements of more stable operation, the research took the 2ZG-6DK rice transplanter as the research object to carry out a vibration reduction optimization study. In the research, the Pro/Engineer 5.0 software was first used to model the chassis of the rice transplanter. The constructed finite element model was revised by using the structural parameter revision method and the mixed penalty function method. The model was imported into ANSYS Workbench to solve the modal frequency and vibration shape of the rice transplanter chassis. Based on the MAC (modal assurance criterion) criterion, modal tests were carried out to verify the accuracy of the finite element theoretical analysis. Through the analysis of the characteristics of the external excitation frequency, the chassis is structurally optimized to avoid resonance caused by the natural frequency of the chassis falling within the road excitation frequency range. The final optimization results showed that the first four orders of modal frequencies of the chassis were adjusted to 32.083 Hz, 33.751 Hz, 42.517 Hz, and 50.362 Hz, respectively, in the case that the chassis mass was increased by 6.714 kg (8.8%). They all avoid the range of road excitation frequency (10-30 Hz) so that the rice transplanter can effectively avoid the resonance phenomenon during operation. This study can provide a reference for the design and optimization of the chassis structure of transplanter. Keywords: transplanter chassis, vibration, finite element analysis, modal experiment, MAC criterion, optimization design DOI: 10.25165/j.ijabe.20221505.6230 Citation: Chen K K, Yuan Y W, Zhao B, Jin X, Lin Y, Zheng Y J. Finite element modal analysis and experiment of rice transplanter chassis. Int J Agric & Biol Eng, 2022; 15(5): 91–100.

Resonance Analysis and Vibration Reduction Optimization of Agricultural Machinery Frame—Taking Vegetable Precision Seeder as an Example

In order to solve the problem of vigorous vibration of agricultural machinery frames, taking a vegetable precision seeder as an example, the concept of vibration reduction was proposed. The modal analysis of the frame was carried out, and the accuracy of the finite element model was verified by comparing the modal test of multipoint input and multipoint output (MIMO) and simulation results. Additionally, the main frequency of engine vibration was the main excitation source of frame resonance. According to the modal shapes, it was proposed to increase the fixed beam structure and to carry out simulation tests. The time-domain signal of the maximum deformation position in the first-order vibration mode was measured, and the vibration spectrum analysis maps before and after optimization were obtained by Fourier transform. A field experiment showed that the seeding quality of the whole machine was significantly improved after optimization. This study provides a reference for the analysis of vibration characteristics and the vibration reduction design of the agricultural machinery equipment.

UM-SIMULINK Co-simulation for the vibration reduction optimization of a magnetorheological damping steel-spring floating slab track

To further mitigate the low-frequency vibration of a vibration source induced by the natural frequency vibration of a floating slab track (FST), the key parameters including the maximum damping force and the displacement threshold of magnetorheological dampers (MRDs) were studied under different subway operating conditions. A Graphical user interface (GUI) co-simulation was proposed to investigate the dynamic responses of a magnetorheological damping Steel-spring FST (SSFST). The mitigation effect of different MRD parameters on vibration sources was evaluated with the environmental vibration prediction model. MRDs could reduce the Z-weighted vibration level of the FST and the tunnel wall simultaneously, but the control strategy was necessary to prevent excessively amplifying the mid-high frequency vibration of the tunnel wall. The deterioration of the track irregularity and the train characteristic frequency close to the natural frequency of the FST required an appropriate increase in the MRD maximum damping force. The displacement threshold should be determined in combination with the dynamic displacement generated by the axle load and the corresponding vibration reduction effect. When the same desired effect is obtained, the parameter matching with a smaller MRD damping force and a larger displacement threshold is recommended.

The vibration reduction optimization of the body tube fastening of EM rail launcher

In order to further optimize the vibration reduction effect of the body tube fastening of the electromagnetic rail launcher, the vibration reduction optimization scheme of the body tube fastening is determined by the modal superposition method. The electromagnetic rail launcher is simplified to Bernoulli-Euler beam, the vibration equation of the rail is established, and the inherent characteristics of the rail are analyzed. The multi-field coupled finite element model of the electromagnetic rail launcher is established and the complete transient launching process of the launcher is simulated. Based on the modal analysis of the system stiffness at the critical velocity, the optimal position of the tube fastening is determined, and the influence of different fastening positions on the damping effect is analyzed. The results show that the fastening of the body tube can effectively improve the structural stiffness of the electromagnetic rail launcher, and the damping effect of the fastening is affected by the vibration characteristics of the fastening position. The addition of fastening leads to the stress concentration in the adjacent part of the rail, which increases the requirement of rail strength. When the fastening is set in the front part of the rail, the vibration reduction effect is obvious. When it is set in the back part, the resonance range of the critical velocity should be avoided and the priority should be given to the position before the critical velocity.

Vibration reduction optimization for mistuned bladed disk based on reduced order modeling technique

The arrangement optimization algorithm of blades can reduce the vibration localization of mistuned bladed disk in a compressor of aero-engine, however, it will destroy the dynamic balance of bladed disk. A new arrangement optimization method of isolation zone on bladed disk system considering unbalance moment is proposed, on the basis the reduced order modeling technology. This method is based on the finite element model and can be implemented as fast and accurate vibration reduction optimization without destroying the mass balance of the bladed disk system, the method considers both mass and stiffness mistuning. Firstly, the discrete particle swarm optimization algorithm is used to sort the mass-mistuned blades according to unbalanced moment, then, the arranged bladed disk is divided into 6 isolation zones, then, in each isolation zone, the stiffness mistuned bladed disk is arranged optimally by the stiffness mistuning optimization algorithm. Under the premise of satisfying the dynamic balance of bladed disk, this algorithm optimizes the arrangement of blades with mass mistuning and stiffness mistuning, and achieves the purpose of vibration reduction optimization of mistuned bladed disk. The results show that, the maximum amplitude of the bladed disk system is reduced by 23.9 %. The vibration localization degree of the optimized blade are reduced by 46.3 %.

Vibration reduction of rotating frame structure based on quadratic performance index

An efficient method based on quadratic performance index and Lyapunov's second method is developed for the vibration reduction optimization of frame structure rotating at a constant angular velocity. Four optimization formulations and algorithms are studied for both low and high angular velocity. These formulations consider both linear vs nonlinear dynamic models as well as direct integration and Lypunov method to evaluate performance index. Three numerical examples are presented to compare the effectiveness of the four algorithms. Numerical results show that all the four optimization methods can reduce vibration at low rotating speed and find very similar optimal designs. However, at high rotating speed, dynamic model of rotating structure must consider nonlinear axial strain in order to obtain correct dynamic response. Since the Lyapunov's second method is not applicable for the nonlinear model and the NFTI (nonlinear dynamic model with nonlinear axial strain and time integration) method is very inefficient, the present study develops a perturbation method, linearizes the nonlinear dynamic model and establishes the LNFLA(linearized dynamic model with nonlinear axial strain, the Lyapunov's second method). Numerical examples show the optimization method LNFLA provides an efficient numerical method for vibration reduction of rotating frame structure with both low and high rotating speed.

Coupled modeling and dynamic characteristics of TBM cutterhead system under uncertain factors

The cutterhead system is the most critical component of a tunnel boring machine (TBM). Because of its complex structure and the influence of many uncertain factors, which not only aggravate its vibration damage, but also make the prediction of its dynamic characteristics and the damage-resistant design very challenging, coupled modeling and the dynamic characteristic analysis of cutterhead system under uncertain factors are of great significance. In this paper, firstly, we considered the influence of geology and cutter position, the geological uncertainty model and the uncertainty model of the cutter position were established for the first time. The combination and transformation of the uncertainty model and the obtained load interval were realized successfully. Then, the load interval was substituted into the dynamic model, the multi-degree-of-freedom coupled dynamic model of the cutterhead system under uncertain factors was obtained. We combined interval theory with the central difference method to solve the dynamic model and obtained the dynamic response boundary. The necessity of considering uncertainty and the effectiveness of this method were verified by comparing the data under uncertain factors with the field test data and simulation data. Finally, we applied our method to an engineering cutterhead system. The results showed that (1) The five-part cutterhead has better vibration characteristics than the integrated cutterhead and two-part cutterhead; (2) When the mass of the center block accounts for 45–46% of the total, the vibration amplitude is the smallest. This provides a very important theoretical reference for structural design and vibration reduction optimization of the cutterhead system.

Study on Design and Vibration Reduction Optimization of High Starting Torque Induction Motor

Induction motors are widely used in various applications. This study considers a Y2-200L2-6 three-phase induction motor. Its starting torque was improved by combining the characteristics and design method of a star-delta hybrid connection winding, which can meet the demand of the motor for oil fields. Meanwhile the electromagnetic vibration and optimization of vibration reduction were studied based on the improved motor. The electromagnetic performance of the improved motor was calculated, and the electromagnetic force distribution of the motor was obtained based on the results of the transient magnetic field. Based on the calculation results of the electromagnetic force, a transient dynamic analysis of the motor was performed, and the electromagnetic vibration displacement curve of the motor was obtained. The experimental results of the vibration were compared with the finite element simulation results to verify the validity of the calculation method. The optimal design scheme of the stator winding was proposed based on the characteristics of the winding connection. The radial electromagnetic force and electromagnetic vibration displacement of the motor before and after winding optimization were compared, and the feasibility of the optimization scheme in reducing electromagnetic vibration was verified.

Vibration reduction optimization of the mistuned bladed disk considering the prestress

Ignoring the effect of prestress can increase the gap between the actual results and research results, which is not conducive to improve the vibration localization of bladed disk system and the finite element calculation. To improve the vibration localization and computational efficiency, the prestressed component mode synthesis method (PCMSM) was adopted to establish the finite element reduced-order model considering prepress. Since the main calculation precision of the prestressed component mode synthesis method was the mode truncation number, calculation was made to the eigenfrequency of different mode truncations; the contrast and analysis were made to the calculation result of blisk model, minimum mode truncation number under the above calculation precision was obtained, and freedom of the model was greatly reduced. The finite element reduced-order model was collocated to make an analysis of the vibration response characteristics of mistuned bladed disk. From the aforementioned analysis, the maximum amplitude of mistuned bladed disk was not only associated with the mistuning value of blade but also related to the frequency of adjacent blade; on the basis of such a rule, the finite element reduced-order model was adopted to raise an optimization algorithm for the blade vibration reduction and arrangement. Results have revealed that the optimization algorithm has made an adequate consideration of both model precision and calculation speed. The maximum dimensionless amplitude of blade vibration under three mistuning patterns and upon optimization is greatly reduced by 32.8%, 30.1%, and 28%. The localization factor of blade vibration under three mistuning patterns and upon optimization is greatly reduced by 64%, 68.5%, and 57.2%. The optimization algorithm based on the prestressed component mode synthesis method gets the optimization value by not more than 15 iterations. The optimization algorithm has greatly reduced the amplitude of the blade and obviously dampened vibration localization of the bladed disk system.

Optimization of vibration reduction of the rubber floating-slab tracks

The floating-slab track is one of the best methods to reduce the vibration from the underground railway. In this paper, the rubber floating-slab track was studied. The train-track model coupled with the track-tunnel-surrounding soil model was built, which was verified by the results of the in-site test. Through this model, the quality of the rubber floating-slab track was optimized by the multi-island genetic algorithm. The optimized Z vibration level was reduced by 4.92 dB with the density of the floating slab 2306 kg/m3, the Young’s modulus of the floating slab 3.21×1010 N/m2, the density of the rubber bearing 730 kg/m3 and the Young’s modulus of the rubber bearing 9.55×108 N/m2.

STABILITY ANALYSIS AND VIBRATION REDUCTION FOR A TWO-DIMENSIONAL NONLINEAR SYSTEM

This study examines how the vibration absorbers influence the stability of nonlinear flow-solid interaction systems. A novel approach is proposed for the analysis of dynamic stability of the two-dimensional nonlinear system using the internal resonance contour plot (IRCP) and flutter speed contour plot (FSCP). The system considered is a planar rigid-body with plunge and pitch vibrations. The two ends of the body are supported by cubic nonlinear springs with quadratic damping. The vibration absorber attached beneath is also considered as a rigid body, with the mass and position of the absorber adjusted for optimization of vibration reduction. The method of multiple scales (MOMS) is employed to obtain a fixed point solution. The P-method is also adopted to obtain the eigen plot and Poincaré Map for comparison. Finally, both the IRCP with FSCP are cross-referenced to provide guide-lines for identifying the optimal location for the absorber with regard to stability and vibration reduction without the need to alter the framework of the main body.