28 January 2023, Volume 42 Issue 2
    

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  • CHEN Jufeng1,2,SHEN Yongjun1,3,ZHANG Jing4,LI Xianghong2,WANG Xiaona5
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 1-6.
    Abstract ( 221 ) Download PDF ( 76 )   Knowledge map   Save
    The stability and existence conditions of Hopf bifurcation of a commensurate Rayleigh system with time-delayed feedback are studied. Firstly, the necessary and sufficient conditions for the asymptotic stability of the equilibrium point of fractional-order Rayleigh system with linear velocity  feedback are obtained, and it is found that the conditions are not only related to the feedback gain, but also to the fractional order. Secondly, regarding time delay as a bifurcation parameter, the stability of the commensurate fractional-order Rayleigh system with time-delayed feedback is investigated based on the characteristic equation. Under some conditions, the critical value of time delay is calculated. The equilibrium point is stable when the parameter is less than the critical value and will be unstable if the parameter is greater than it. Moreover, the conditions for the occurrence of Hopf bifurcation are obtained. Finally, choosing three typical system parameters, some numerical simulations are carried out to verify the correctness of the obtained theoretical results.
  • SU Yuewen1,GUO Caixia1,WANG Canjun1,ZHU Aibin2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 7-15.
    Abstract ( 204 ) Download PDF ( 24 )   Knowledge map   Save
    Manufacturing error is the key factor affecting the transmission accuracy of RV reducer. On the basis of the gear tooth contact analysis method, a new gear tooth contact equation for two-stage transmission of involute gear and cycloidal pin gear is constructed to evaluate the influence mechanism of various manufacturing errors on transmission error of RV reducer considering tooth profile modification, machining error and assembly error. The prediction model of transmission error for cycloid pinwheel mechanism with different manufacturing errors is obtained to calculate the the sensitivities of various manufacturing errors for the transmission error. Sensitivities are also used as the basis for the selection of tolerance levels IT5 or IT6. According to different tolerance levels, manufacturing errors are expressed as Gaussian random numbers. Furthermore the reliability of the RV reducer without interference is analyzed and the distribution of transmission errors are obtained through random sampling errors under each group of error samples. The results show that the position error of the pin and the cumulative pitch error of the cycloid gear have the greatest influence on the transmission error, the eccentricity error of involute gear and crank shaft has little influence, and the influence of the pin radius error is the least. When the machining errors with lower sensitivity are set to IT6 and the ones with higher sensitivity are IT5, the transmission error accuracy requirements when all machining errors are IT5 can be obtained, the reliability is 98%, and the machining cost is lower. It can be as the basis for the manufacturing tolerance selection and the cost control of RV reducer. 
  • DONG Xiaoxin,ZHAO Rongzhen
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 16-22.
    Abstract ( 163 ) Download PDF ( 63 )   Knowledge map   Save
    Aiming at the difficulty of fault classification caused by "dimension disaster" in fault feature set, a dimension reduction algorithm of fault feature set based on enhanced intrinsic local preserving discriminant analysis (SILPDA) is proposed. The algorithm integrates the enhanced multi manifold intrinsic model and local similarity matrix into the construction of the objective function. During this period, the multi manifold structure characteristics of the data set are fully considered and the local structure information of the sample is retained, so that the low dimensional feature subset after dimensionality reduction is easy to implement classification operation, and then achieve the effect of improving the accuracy of fault identification. The performance of the algorithm is verified by using the original fault feature set constructed from the vibration signal set of the rotor test-bed. The results show that the algorithm can extract sensitive feature subsets that are conducive to the implementation of classification operation from the original fault data set. These feature subsets will make the boundary between different fault categories clearer. Finally, compared with "LPP, LDA, LMDP" and other algorithms, the algorithm can achieve better fault identification effect. For improving the value density of rotating machinery big data resources, this algorithm provides a theoretical basis for optimizing the data structure model.
  • WANG Ming1,2,XU Huidong1,2,HE Dongping1,2,WANG Tao1,2,WANG Yiping1,2,REN Chaoran1,2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 23-34.
    Abstract ( 186 ) Download PDF ( 68 )   Knowledge map   Save
    Vertical vibration often occurs in the rolling mill during high-speed rolling, this vibration behavior will affect the stability of the rolling process and the surface quality and bonding strength of the composite plate, which is not conducive to efficient and continuous rolling production. In order to suppress the vertical vibration of the rolling mill roll system during the rolling process, a multi-degree-of-freedom particle damping vibration absorber is designed in this paper. Establish the model of vertical nonlinear parametric vibration of the upper work roll on the rolling mill with absorber. Using the multi-scale method, the amplitude-frequency characteristic equation of the system is solved, simulation and analysis the singular characteristics, time domain characteristics, frequency spectrum characteristics and amplitude-frequency characteristics of the vibration system. The vertical vibration control experiment was carried out on the upper work roll of statically determinate rolling mill, the comparison found that the theoretical analysis is basically consistent with the experimental results, prove the reliability of the established four-degree-of-freedom vibration model, the results show that the particle damping vibration absorber can effectively suppress the vertical vibration of the rolling mill roll system and meet the design requirements.
  • ZHENG Hualin1,JIN Huanbing1,WANG Xiaohu1,LI Yanjun2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 35-42.
    Abstract ( 211 ) Download PDF ( 109 )   Knowledge map   Save
    Taking the typical dual-rotor-inter-shaft bearing system of aero-engine as the research object, influence of airflow excitation force and the characteristics of dual-rotor inter-shaft bearing, the dynamic characteristics of dual-rotor system including airflow excitation Alford force and nonlinear force of inter-shaft bearing are studied. The dynamic model of the system was established by using the Euler-Bernoulli beam theory, and the nonlinear intermediate bearing force and Alford force were introduced into the model. The finite element method and Newmark-β method was used to solve the dynamic response of the system. The calculation results show that Alford force affects the motion of the system in the form of combined frequency and continuous frequency, and it is easy to excite the nonlinear characteristics of the intermediate bearing force. Alford force increases the critical speed of the system .With the increase of rotational speed, the influence of intermediate bearing force on rotor system decreases, while the influence of Alford force increases. In addition, the change of the clearance of the intermediate bearing is deeply coupled with the characteristics of the Alford force. Under different clearances, the bearing force and the Alford force jointly cause different motion states such as period, quasi-period and chaos of the system.
  • LI Ling,HE Benshuai,WANG Jingjing,ZHANG Jinhua,CAI Anjiang
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 43-50.
    Abstract ( 215 ) Download PDF ( 138 )   Knowledge map   Save
    A method using the equivalent asperity of a quadratic rotating body is proposed based on rough surface topography measurement experiments. The analytical relationship between the contact radius and the contact deformation of the asperity is established, which makes up for the defect of a single radius of curvature in the hemisphere model. Then, the contact expressions of a single asperity in three deformation stages of elastic, elastoplastic and fully plastic are deduced through the geometric model. The microscopic contact model of the rough surface is established based on the theory of contact mechanics and statistical methods. Finally, the simulation results of the model are compared with CEB model, ZMC model and KE model to verify the validity. Furthermore, the influence law of plasticity index and asperity size parameters on contact characteristics is revealed. The results show that the quadratic function model is better than the hemisphere model in fitting the contour of the asperity. The model can more accurately analyze the contact characteristics of the joint surface under higher loads. Additionally, the plasticity index is the main factor affecting the contact stiffness, and the contact area decreases with the increase of the plasticity index, resulting in a weaker ability to resist deformation. The influence of asperity size parameters on contact stiffness is relatively small, and the contact area and contact stiffness increase with the increase of the ratio of asperity diameter to height.
  • WANG Debin1,HE Jie1,SUN Zhiguo2,WANG Dongsheng3
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 51-59.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The energy dissipation function could not be fully used in the traditional self-centering braces. A torsional friction self-centering brace with displacement amplification function (SC-DARFB) was proposed based on the working principle of the bridge type amplifier. The basic structure and working principle of the SC-DARFB was introduced, and its theoretical restoring force model was proposed. The mechanical properties of the braces under different initial amplification angles were studied by numerical simulation, and the seismic response of the double-column pier with SC-DARFB was analyzed. It is found that the hysteretic performance of the SC-DARFB can be effectively described by the proposed theoretical restoring force model, which is in good agreement with the numerical simulation results. With the decrease of the initial amplification angle, the slip load, the maximum load and the energy dissipation capacity of the SC-DARFB are significantly improved, and the SC-DARFB shows good self-centering ability. Reasonable design would ensure that the maximum tension/compression load ratio meets the limit of 1.3 in the American Steel Structure Code. As a result, it is suggested to use an inverted V-shaped symmetrical SC-DARFB. The maximum displacements and residual drift ratio of the double-column piers would be decreased significantly by using the SC-DARFB. The seismic dissipation capacity of the double-column piers can be further improved by reducing the initial amplification angle of the SC-DARFB.
    Key words: frictional energy dissipation; displacement amplification; restoring force;seismic design of bridges; double column pier
  • HUANG Hua1,YAO Jiajing1,WANG Yonghe1,L Yanjun2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 60-67.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the failure of historical model caused by different data distribution in tool wear prediction modeling under the same working condition, a tool wear dynamic prediction modeling method based on multi-channel one-dimensional convolutional neural network is proposed. The multi-channel one-dimensional convolutional neural network trained on historical tool wear data serves as historical model of the initial tool wear prediction. The maximum mean difference method (MMD) was used to detect the similarity of different tool wear data. When the similarity difference is large, the iterative update is carried out on the basis of the historical model, and then the updated model is used to predict the wear data. The results of milling experiments show that the method can accurately predict the wear values of different tools and has great adaptive ability.
  • FAN Yuan,LU Wensheng
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 68-78.
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    More attention has been paid to the seismic performance and design of non-structural components of buildings. Among them, the study of floor acceleration demand can reasonably determine the seismic inputs of acceleration sensitive non-structural components. In this paper, the main structure is simplified by distributed parameter model, and the relationship between floor acceleration and seismic input and structural characteristics is established. The influence of flexural to shear stiffness ratio on structural dynamic characteristics and modal shape is studied. Based on the relationship between the frequency ratio of each order of modes and the stiffness ratio, a method for identifying the stiffness ratio of the structure is proposed. The far-field and near-field strong motion record data set from ATC-63 report is selected to predict the Floor Acceleration Amplification (FAA) factor. The relationship between floor acceleration amplification with structural damping ratio, period, stiffness ratio is regressed and fitted, and this relationship can be used to predict the floor acceleration.
  • WANG Weiyin1,WANG Zuocai1,2,XIN Yu1,3,DING Yajie1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 79-88.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To simultaneously consider the effects of multiple uncertainties on nonlinear structural model updating, a stochastic nonlinear model updating method based on modular Bayesian inference is proposed. In this study, the instantaneous acceleration amplitude of the main component of the structural dynamic response is extracted as the nonlinear indicator. Based on the proposed approach, the nonlinear model updating is divided into three modules. Firstly, a Gaussian process alternative model of the nonlinear model is established as module 1; meanwhile, to consider the influence of the model uncertainties on nonlinear model updating, a Gaussian process model is further constructed in module 2, in this model, the design variables are assigned as input and the model error is designed as output. Finally, combing with the modules 1 and 2, the posterior probability density function of the nonlinear model parameter is estimated by using the Transitional Markov Chain Monte Carlo (TMCMC) Random sampling method. Numerical simulation on a three-span continuous girder bridge is used to verify the accuracy of the proposed stochastic nonlinear model updating method, and the updating results under different noise levels and different model uncertainties are investigated. The results show that the proposed method is effective for stochastic nonlinear model updating with a better robustness.
  • YAN Xiaojia1,LIANG Weige1,ZHANG Gang2,SHE Bo1,TIAN Fuqing1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 89-99.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The problem of imbalance and limited training data is the key factor that restricts the application effect of deep learning technology in the field of fault diagnosis of complex feeding and ramming mechanism. In order to overcome the shortcomings of traditional deep learning methods that are difficult to obtain the internal distribution of limited data and the defect that traditional unbalanced data processing methods do not consider the equalization of category information, a fault diagnosis method for complex feeding and ramming mechanism based on wavelet time-frequency diagram and SAE-ACGANs is proposed. Firstly, the continuous wavelet transform (CWT) is performed on the vibration signal of the feeding and ramming mechanism to obtain a two-dimensional time-frequency diagram reflecting the time-frequency characteristics of the signal. Then, the sparse encoder in the model is used to extract image features and merge them with category information into hidden variables. It is used to strengthen the ability of latent variables to represent the characteristics related to the category of the image. After that, the generator maps the fused latent variables to generated samples similar to the real sample distribution to expand the training data set. The discriminator mines effective depth features from the extended data set and realizes the judgment of the authenticity and category of the sample. Finally, through adversarial learning and training mechanism, the optimized generator and discriminator alternately optimize each other to achieve the Nash balance. The method improves the sample generation quality and fault judgment ability with a unbalanced limited training data. The research results of the test bench for complex feeding and ramming mechanism show that: The SAE-ACGANs framework can fully learn the internal distribution and depth characteristics of the input samples. Compared with the original ACGANs framework, the method improves the performance of the discriminator, and realizes the improvement of model convergence speed, training accuracy and stability. Compared with traditional unbalanced data processing algorithms, the model's ability to identify minority fault samples is greatly improved.
  • ZHU Dapeng1,WANG Haoran1,CAO Xingxiao2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 100-107.
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    In many cases, the package is excited by non-Gaussian random vibration loads, in circumstances where the packaging system optimization and package parameters optimization are performed, the package acceleration response statistical characteristics and vibration reliability needs to be determined repeatedly. Therefore, in this paper, an efficient and accurate analytical method is proposed to determine statistical characteristics of nonlinear package acceleration response. By use of non-Gaussian Karhunen-Loeve expansion, the stationary non-Gaussian random vibration is expressed as the linear combination of uncorrelated non-Gaussian random variables, the package acceleration response is approximated by first order Taylor expansion, the statistical characteristics of package acceleration response are determined analytically. The probability density function(PDF) and cumulative distribution function(CDF) of package acceleration response are determined using the saddlepoint approximation method, based on the first four statistical moments of package acceleration response. Since the linear combination of non-Gaussian variables is used to express the excitation, the nonlinear transformation of random variables is avoided, the first order Taylor expansion approximation for the response has good accuracy. The PDF and CDF of package response are determined analytically by use of saddlepoint approximation, the Monte Carlo(or Quasi Monte Carlo) simulations are avoided, the analysis efficiency is improved greatly.
  • SUN Yilong1,XU Chengshun1,XI Renqiang1,2,DU Xiuli1,DOU Pengfei1,3
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 108-115.
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    Offshore wind turbine structures usually suffer wave, wind and other external lateral cyclic loads. The long-term cyclic loadings cause the variation of foundation stiffness. The offshore wind turbine structural system is sensitive to these dynamic cyclic loads, so it is very important to predict the long-term effect of cyclic loading on the natural frequency. This study developed a method to analyze the natural frequency of offshore wind turbine structural system with considering soil-pile interaction and the effect of long-term cyclic loading. This method is based on the kinematic equation of the damped system, considering the long-term effect of cyclic loading on the foundation stiffness by embedding the foundation stiffness degradation model. This method was then validated against engineering data and numerical calculation. Parameter studies were conduct to present the influence of the cyclic loading amplitude, cyclic number and pile diameter on the natural frequency of offshore wind turbine structure system by using the developed method. The results showed that the natural frequency of the offshore wind turbine structural system would decrease with increasing cyclic loading amplitude and cyclic number, and the natural vibration frequency of the fan structural system would be biased towards 1P with increasing the cyclic number. This method can be used to evaluate the natural frequency of monopile supported offshore wind turbine structure under the long-term cyclic loading, and provide some reference for the design of natural frequency of offshore wind turbine.
  • LIU Zhibin1,2, 3,4,TAN Ping1,2,3,4,WANG Jingjing1,CHEN Yangyang2,3,4
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 116-125.
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    This paper proposes a novel asymmetric inerter nonlinear energy sink(NES), which is composed of an asymmetric NES and an inerter element, to reduce the mass of dampers and improve the seismic mitigation performance of NES. The working principle of asymmetric inerter NES was presented, and the equations of motion of asymmetric inerter NES-attached system are derived. Asymmetric inerter NES is optimized under impulsive excitations to analyze the energy and frequency robustness of the proposed asymmetric inerter NES. Control performance and wavelet spectrum analysis of Asymmetric inerter NES under the action of earthquakes. Numerical results show that the proposed asymmetric inerter NES is as effective as asymmetric NES in response mitigation under seismic excitations and exhibits strong robustness against changes in both the energy level and the structural frequency but asymmetric inerter NES is preferred with a much smaller stroke demand and reduces the mass of dampers. Therefore, Asymmetric inerter NES demonstrates great potential as an effective control strategy for seismic response mitigation of building structures.
  • ZHAO Zhihong1,2,LI Chunxiu1,DOU Guangjian1,YANG Shaopu2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 126-131.
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    Bearing fault diagnosis is very important to ensure the safety of mechanical equipment. In recent years, data-driven fault diagnosis methods have attracted the attention of researchers. Unlike the traditional fault feature extraction methods that rely on expert experience, the deep learning method can realize end-to-end automatic fault feature extraction and classification. In response to the problem that one-dimensional signal cannot fully exploit the relevant information between data when used as input to a convolutional neural network (CNN), a bearing fault diagnosis method based on a MTF-CNN is proposed. The collected vibration signals are encoded by the Markov transition field(MTF), the data correlation in different time intervals is obtained according to the transfer probability between data, and the corresponding feature map is generated. Then, it is input to a CNN to complete feature extraction and fault classification. The model is verified by the bearing dataset of Case Western Reserve University. The experimental results show that the fault diagnosis accuracy of the model is over 99.8%, and better generalization performance is obtained compared to other image coding methods.
  • LI Boli,ZHAO Sihan,LIU Yuanmeng,YANG Jianhui,GUO Weiguo
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 132-138.
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    In both civilian and military fields, equipment or structural components are often subjected to repeated impacts with high loading rates, namely impact fatigue problems. The impact fatigue test device is the basis for studying the impact fatigue problems, therefore an impact fatigue test method based on the split Hopkinson bar is presented in this article, where the impact projectile is reset by vacuum system, the incident bar is limited by elastic restraint during the loading process, and the transmission bar and the specimen are reset by an electric push bar. The above process is controlled by the PLC controller. The continuous real-time display of waves through signal acquisition on the bar can be realized by this method which is easy to operate and can change the geometric configuration of the impact projectile to produce loading wave with different wave configurations (trapezoidal wave, triangle wave and half sine wave) and different loading rates (8×105~3×106MPa/s). Meanwhile, the loading frequency ranges from 0 to 0.5Hz. Finally, the applicability of the method is demonstrated in this paper with test results for high-strength steel cylindrical specimens and three-point-bending specimen processed by additive manufactured 316L stainless steel with process defects.
  • LI Jingxian,WANG Cong,ZHANG Hongli,ZHANG Shaohua
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 139-148.
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    As a complex and unstable nonlinear dynamic behavior, Chaos can easily lead to the oscillation and instability of the power system, and threaten the safe and stable operation of the power system seriously. Based on the finite time theory, this paper proposes a finite time command filter adaptive control method considering static error elimination for chaotic power systems. Firstly,the radial basis function neural network is used to achieve the approximation of the unknown nonlinear function in the power system model. Secondly, the command filter and error compensator are added to realize the derivation and error compensation of the virtual control signal. Finally, in view of the static error problem in the control, introducing the error integral feedback law, design the system's control law through the backstepping method to satisfy the finite time stability, and realize the tracking of the target signal in the chaotic state of the power system, thereby realizing the chaotic control of the power system indirectly. The simulation experiment proves that the method designed in this paper can effectively suppress the chaotic oscillation phenomenon of the power system, eliminate the static error in the control process, further weaken the coupling relationship between the control variables, and ensure the normal operation of the power system.
  • LAN Shuwei1,ZHOU Donghua2,CHEN Xu1,WANG Chunhua1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 149-156.
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    In view of the inconvenience of determining the overall stability of frames by the standard calculation length method for each component checking and the lack of not being able to consider the mutual support between the same layer columns and the inter-story interaction, this paper describes the physical meaning of the instability of sway steel frames based on the spring-swinging column model. Through the concept of structural transformation, first this paper use the frame repeating unit to solve the floor lateral stiffness and the critical stiffness ratio coefficient to solve the floor load stiffness, and then the floor lateral stiffness and the floor load stiffness are assembled as a whole, and the second-order calculation for solving the overall stability critical bearing capacity of steel frames is transformed into a first-order problem to determine the overall lateral stiffness of frames. Finally, the activation degree of the floor stiffness is considered based on the method of axial force weighted average, and the calculation formula that can directly calculate the critical bearing capacity of steel frame is obtained. This formula can judge the weak layer of frame structures, which can quantitatively calculate the degree of mutual support between floors, and avoid the unreasonable design caused by the standard calculation length method because the two support functions cannot be considered. The results of calculation examples show that this method has good precision and accuracy, which can be used for engineering design.
  • GAO Zhiqiang,CHEN Hanbo,ZHOU Xuesong,MA Youjie
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 157-165.
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    Inverter is a strong nonlinear system, it generally has sophisticated nonlinear dynamical behaviors, for instance transcritical bifurcation, period doubling bifurcation, etc, it will greatly increased the harmonic component of the output current, decrease the efficiency rate of the convertor, make it oscillate and even collapse. At present, most of chaos control has the disadvantages of modeling difficulty, control effect is not obvious and stability is not strong. To solve this problem, a new chaos suppression method, namely improved cosine delay feedback control (ICDFC), is proposed. In this method, the difference value between the export variable of the controlled object and itself time delay of one period is first used as the feedback quantity, which then passes through the cosine function and feedback control parameters to obtain the controlling message, after that the controlling message is directly reaction on the controlled subject in feedback forms. In the meantime, establishing system’s stroboscopic mapping model, seeking the Jacobin matrices and balance points of the controlled object. At last, the restrictive conditions of the feedback controlling parameter is presented based on the July criterion. To illustrate the superiority of the suggested chaotic control method, a great deal of simulating experiments were unfolded, and compared with exponential delayed feedback control which proves that ICDFC can not only suppress the chaotic behavior of the inverter more effectively, but also largely increases system operational stable region.
  • YANG Chaofeng1,2,ZHOU Yunjiao3,HUANG Xianglong2,LI Feng4,LI Youyi4,LIU Feifei1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 166-174.
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    Using experimental methods, the static and dynamic characteristics and internal characteristics of different structural hydraulic bushings under different amplitudes and different frequencies were tested. A unified multi-inertial tracks-multi-orifices hydraulic bushing lumped parameter model is derived, and the dynamic characteristics of the hydraulic bushing are described. A unified multi-inertial tracks-multi-orifices hydraulic bushing fluid flow response in the fluid channel and the response equation of pressure fluctuations in the fluid chamber are established. The calculation parameters of the physical model of the hydraulic bushing are obtained by the combination of direct fluid-solid coupling and fixed points. The calculation results are compared with the test to verify the correctness of the model. The calculation analyzes the internal characteristics of different structural hydraulic bushings under different amplitude and frequency excitation, and compares the theoretical derivation and experimental data to verify the correctness of the calculation and analysis results. The calculation method in the article can provide a direct reference for the initial selection, design and development of hydraulic bushings.
  • YANG Yaxun1,2,ZHANG Weide1,YU Haibo1,CHAI Wenhao1,LIU Dechuang1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 175-181.
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    In the study of the relationship between five ultrasonic parameters (wave velocity, first wave amplitude, main frequency amplitude, non-linear coefficient and ultrasonic spectral area) and stress in loaded concrete simulated by support vector machines, in order to improve their operational efficiency and optimisation results. The effect of different normalization methods and kernel functions on the effectiveness of finding the correlation between ultrasonic parameters and stress is compared through numerical simulations, and the simulation results of three types of support vector machines, namely empirical parameters, traversal algorithm optimized parameters and particle swarm algorithm optimized parameters, are investigated experimentally. The results show that the proposed first normalization method is more suitable for the special problem of ultrasonic parameters and stress, and the kernel function is better than the radial basis kernel function; the simulation results of different support vector machines differ significantly, and the simulation results of the simple support vector machine are poor, especially in the low stress stage; the results obtained by the model optimized by the traversal algorithm are better, but the computation time is too long, and the judgment error in the low stress stage is The particle swarm algorithm optimises the support vector machine to reduce the computation time significantly compared to the traversal algorithm and gives the best simulation results.
  • GAN Shengyong1,2,3,WEI Xiaohui1,2,3,FANG Xingbo1,2,3
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 182-188.
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    In order to analyze the damping characteristics of the landing gear oil hole, the lattice Boltzmann method was used to analyze the influence of oil hole geometric parameters and operating environment parameters on the oil flow characteristics. Based on the single parameter analysis results and the least squares method, the damping force regression equation was established and verified. The results show that the lattice Boltzmann method can accurately analyze the oil hole damping performance. The oil hole length changes the position of the flow minimum contraction section in the oil hole, the variation of the oil hole diameter in a limited interval has little effect on the discharge coefficient, and the increase of the backpressure improves the oil hole flow quality. The regression equation can predict the damping force reliably in the design interval, and the method can be used in general landing gear oil hole design.
  • WEI Yufeng,HE Weiling,JIANG Xiangzeng,HE Yuxiang
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 189-196.
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    The high-soft tower wind turbine has the characteristics of light weight, high rise and low damping, which makes it more sensitive to the dynamic response of various excitation sources. The identification and research of vibration sources is of great significance to the safety evaluation of the unit during operation. In this paper, taking the tower of a 140 meter high-soft tower wind turbine as the research object, the vibration response signals at different heights are measured, and the main vibration source types and characteristics inducing tower vibration are identified by spectral kurtosis method. The measured signals are decomposed by wavelet packet decomposition and wavelet packet energy principle to obtain the frequency domain components and energy proportion representing the characteristics of each vibration source, Finally, the vibration source characteristics and energy proportion at different working conditions and different measuring points are counted. It is found that the tower structure is always excited by periodic strong vibration sources such as its first-order natural vibration and wind turbine rotation in the whole life cycle of wind turbine. With the increase of power generation, The strong vibration source changes from the single first-order natural vibration excitation to the combined excitation of first-order natural vibration and wind turbine rotation, and then to the complete wind turbine rotation excitation. In the high speed region, the frequency doubling of wind turbine is close to multiple modal frequencies of tower, which is very easy to cause resonance.
  • SHEN Chaoming1,HUANG Jie1,CHEN Molin1,QIAN Denghui1,WANG Jianchun2,ZHUANG Jiawei1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 197-204.
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    To suppress the propagation of vibration and noise in engineering, a kind of phononic crystal beam structure was designed. Based on the Bloch theorem of periodic structure, the band structures,displacement fields of eigenmodes and transmission power spectrums of the corresponding finite periodic phononic crystal beam structure are calculated by a finite element method. And the band gap characteristics of its display is studied. Based on the main mechanism of local resonant band gap formation, the phononic crystal beam structure of low frequency vibration and noise control is studied, which can be applied to the vibration and noise reduction of specific frequency in engineering. The band gap characteristics of phononic crystal veneer beam and phononic crystal double-layer beam are analyzed, and the commonness of phononic crystal single/double layer beam is studied. The influence of various parameters on the band gap attenuation band of phononic crystal beam structure is studied, and the low frequency vibration isolation in a specific range can be realized through reasonable design of parameters, which has a good application prospect in the field of vibration and noise of ships and other engineering.
  • RAN Feng1,ZHU Caichao1,TAN Jianjun1,SONG Chaosheng1,ZHU Yongchao1,CHEN Shuai2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 205-215.
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    With the development of wind turbine gearbox towards 10MW and above ultra-high power, the problem of the full-size testing is limited by the power of the test stand becomes more and more obvious. In this paper, an equivalent scaling method is proposed for the transient dynamic response of the megawatt-level wind turbine gearbox transmission system. Taking a certain type of 5MW wind turbine gearbox as the research object, a wind turbine gearbox transmission system variable speed dynamic model is established by dimensional theory. The dynamic similarity relationship of equivalent reduction of wind turbine gearbox transmission system suitable for variable speed conditions is analyzed, and the inherent characteristics and vibration response of the prototype and scaled wind turbine gearbox transmission system are compared and analyzed. The research results show that the natural frequency and mode shape of the scaled wind turbine gearbox transmission system meet the similar relationship with the prototype, and the steady-state response and transient response of the scaled wind turbine gearbox transmission system meet the similar relationship with the prototype, and the maximum error is less than 3%. This method can provide a certain reference basis for the equivalent scale design of wind turbine gearbox.
  • YU Chunlei1,JI Haojie2,MENG Zhongliang1,3,LU Jili1,XU Wei1,C.Chiu1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 216-224.
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    The curved beam structure has a series of advantages including beautiful appearance, good mechanical properties and strong bearing capacity etc and it has been widely used in construction, bridge, ship, aerospace and other fields due to the above advantages. Firstly, a unified dynamic analysis model of curved beams with complex boundary conditions is established by using Hamilton's principle based on the theory of first-order shear deformed beams. Four typical curved beam structures including circular curved beam, elliptic curved beam, parabolic curved beam and hyperbolic curved beam are taken into accounted in this study. Secondly, the convergence of the established curved beam model is verified and the optimal truncation number and boundary spring stiffness are determined according to the above verification. Then, the accuracy of the established curved beam model is verified and it is validated that the established model can quickly solve the vibration characteristics of the curved beam model with complex boundary conditions. Finally, the effects of structural parameters, boundary conditions and pulse load types on the vibration characteristics are investigated and the results show that the thickness, elastic boundary conditions and pulse load types of the curved beam have different degrees of influence on the structure of the curved beam.
  • HAN Mingjun,LI Jinpei,WANG Peng
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 225-234.
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    Based on Von Kármán thin plate large deflection theory and Kirchhoff assumption, the nonlinear vibration characteristics of gradient porous thin-walled plate are studied. Considering the three different distributions of pores along the thickness direction of the wall plate, the Galerkin method is used to transform the gradient porous wall plate and the nonlinear equation is obtained by integrating the aerodynamic chord length. Then the determination of Hopf bifurcation is transformed into the root of the nonlinear equation by using the Hurwitz determinant, and the dimensionless critical frequency and dimensionless critical velocity are solved. Finally, a numerical example is calculated and compared with the results obtained in the existing literature. The effects of temperature stress, porosity and aerodynamic stiffness coefficient on the aeroelastic stability of gradient porous thin-walled plates are analyzed.
  • YANG Longfei1,LI Pu2,YE Yizhou3,FANG Yubin1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 235-243.
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    Thermoelastic damping (TED) is one of the critical coefficients that determines the upper limit of the quality factor of the micromechanical resonators. This paper presents for the first time a general theoretical framework for calculating TED in circular microplate resonators partially covered with multiple coatings. The present model can be degenerated to that of fully covered bilayer cases, and the numerical method also verifies the effectiveness of the current model. At the same time, a simple model for rapid calculation in the engineering design is proposed, and the scope of application of the simple model is analyzed. Finally, the TED frequency spectra behaviors of microcircular plates with 2 coatings are studied, and three Debye peaks in the frequency spectra are found.
  • LIU Qiang, HE Xiping
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 244-250.
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    To efficiently apply Terfenol-D rods, six kinds of rods are studied in this paper. Finite element software was used to analyze and calculate the core loss of rods with different structures, and the dynamic simulation study was performed. Three types of rods were processed, and the output amplitude of the rods was tested experimentally. The results show that the core loss of untreated rod is the largest at the outer diameter surface; the core loss of slicing and slotting rods is reduced, and the core loss of slicing rods is less than that of slotting rods. The overall loss of the radial slitting rod is the largest; the overall loss of the radial cutting and bonding rod and the slicing treatment rod is less than that of the untreated rod and the radial slitting rod; the overall loss of the slicing rod at both ends is greater than that of the slicing and slotting rod and the slicing treatment rod. The untreated rod has the highest resonance frequency, the biggest mechanical quality factor, and the smallest amplitude; compared with untreated rods, the resonant frequency and mechanical quality factor of slicing rods or slitting rods are reduced, and the amplitude is increased; the resonant frequency and mechanical quality factor of the slicing treatment rod are smaller than that of the slitting treatment rod, and the amplitude is much larger than that of the slitting treatment rods.
  • GUO Mingjun1,2, LI Weiguang2, ZHAO Xuezhi2, ZHANG Xinxin2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 251-257.
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    At present, there are few researches on micro-motor fault detection, and the traditional motor diagnosis methods based on single domain features have low accuracy. So, a fault detection method for micro motor based on ensemble empirical mode decomposition (EEMD) and bat algorithm (BA) is proposed. The proposed method includes three steps: construction of sample sets, model training as well as parameters optimization, and model test. Firstly, EEMD processing is carried out to the collected micro motor signals, and the main intrinsic mode fuction(IMF) components are selected by the principle of correlation coefficient, combined with the calculated time and frequency domain features of the motor signals, multi-domain feature set is constructed and normalized. Then, these features are divided into a training set and a test set in a certain proportion. Secondly, the training set is taken as input, the error rate is employed as fitness, and then parameters of KELM model are optimized with bat algorithm (BA). Finally, the optimized BA-KELM model is tested by test set, the experimental results show that the accuracy of the proposed method is 98.75%, which is higher than other methods.
  • SUN Qikai, ZHANG Nan, LIU Xiao
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 258-266.
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    Considering the effect of shear deformation and shear slip, an analytical model for analyzing the dynamic characteristics of steel-concrete composite continuous beams (SCCCBs) is proposed. Firstly, the n-1 intermediate supports of the SCCCBs are replaced by the unknown reaction Ri (i=n-1), so the dynamic problem of the SCCCBs is reduced to that of the simply supported composite beam bearing the unknown loads. Then, the vibration mode function of the SCCCBs bearing unknown reactions is obtained by Laplace transform and inverse Laplace transform. Finally, the linear equations for n-1 unknown reactions can be obtained by substituting the boundary conditions at beam end and the middle supports. The eigenfrequencies of the SCCCBs can be calculated by the the determinant of the coefficient matrix of the linear equations, which is not 0. In the model, the concrete sub-beam and steel beam are considered as independent Timoshenko beam elements respectively, which has higher calculation accuracy than the assumption that both sub-beams have the same shear angle and that the shear deformation is not considered. Finally, the effects of shear deformation, the ratio of side to the main span, and span to depth ratio on the natural vibration characteristics of SCCCBs are analyzed. The results show that the proposed method in this paper has higher calculation accuracy; The influence of shear deformation on the natural frequency of SCCCBs can be ignored, when L/(nh)>10.
  • ZHOU Lijie1, CHEN Kai1, FAN Yongqi2, CHAI Zhaopeng2, WANG Yiwen1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 267-275.
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    The main reduction gear system is an important transmission component of an automobile transmission, and it is also the main cause of vibration and noise of the cabinet. In order to indicate the vibration characteristics of the main reduction system by the internal and external dynamic excitation, a bending-torsion-shaft-pendulum fully coupled kinetic equation is established by the finite element discretization modeling method which discrete the box-shaft into the shaft section and couple it with the input and output shaft section units, gear meshing unit and bearing unit. The box-shaft flexibility, the time-varying meshing stiffness of the helical gear with large coincidence and the static transmission error excitation is considered in the model and the numerical solution is adopted to get inherent characteristics and vibration response characteristics of the system. The research results show that the low-order natural frequency of the system is slightly reduced after the box-shaft flexibility is taken into account, but new natural frequencies and vibration modes are added. By the increase of the speed, there is an obvious order amplitude increase in 1 and 2 times meshing frequency, and an obvious resonance response is appeared when the speed reaches 4900rpm. The result also shows that the increase in external load mainly leads to the rise of the vibration amplitude in non-resonant zone. When the combination of different end-face contact degree and axial contact degree is selected, or the axial contact degree is increased within a certain range, the fluctuation of time-varying meshing stiffness of helical gear can be effectively reduced and the vibration displacement amplitude near the resonance point can be improved.
  • WEN Guozheng, WANG Jiadong, CAO Zhanxue, ZHAO Shilin
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 276-284.
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    The sloshing of liquid in a 2-D rectangular container under horizontal excitation is investigated. The sloshing control device is a rigid vertical baffle. The analytical models of the baffle at free surface are established, respectively. Firstly, the liquid domain is divided into several liquid subdomains has continuous boundary conditions of class C1 by introducing artificial interfaces. Based on the superposition principle, the formal solution of the velocity potential of each liquid subdomain is obtained using the separation of variables method. The formal solution is substituting into the interface between the subdomains and the free liquid surface condition gives the series equation with the determined coefficients. The spatial coordinates in the equation are eliminated by weighted integration, and the characteristic equation is obtained by truncating the equation. The sloshing frequency and mode obtained by the characteristic equation. The total velocity potential function under lateral excitation is taken as the sum of the container potential function and the liquid perturbed potential function. The dynamic response equation with generalized coordinates can be obtained by substituting the perturbation velocity potential and rigid body velocity potential into the wave equation of liquid surface. The sloshing response of liquid in the container is obtained by solving the equation.
  • YUAN Jing, YAO Ze, HU Wenyue, JIANG Huiming, ZHAO Qian
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 285-292.
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    Resonance demodulation technology is an effective method widely used in the field of bearing fault diagnosis, in which the selection of demodulation frequency band is crucial. Traditional demodulation methods can only identify single bearing faults with obvious features, but it is often difficult to extract abnormal weak features for composite faults of rotating machinery bearings and to select multiple optimal demodulation bands caused by different faults. For this reason, the time-frequency energy aggregation spectrum diagnosis method is proposed. The method introduces multisynchrosqueezing transform to construct a time-frequency representation with high energy concentration to solve the problem of optimal demodulation band accuracy, and also proposes the relative factor index of energy aggregation spectrum to realize the comprehensive extraction, synchronization and accurate output of strong and weak multi-fault feature bands through the index, which provides a favorable basis for the extraction and identification of weak and composite bearing fault features in complex dynamic signals of rotating machinery. The experimental results show that this method can successfully extract the bearing compound fault features.
  • ZHAO Zhujie, HOU Hailiang, LI Dian, YAO Menglei
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 293-302.
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    In order to investigate the anti-explosive performance of multicell liquid cabin structure, the concave multicell liquid cabin structure is proposed, and the three-dimensional numerical simulation models of the conventional liquid cabin structure and the concave multicell liquid cabin structure are established. The response and protection characteristics of these two types of structures under the action of explosion shock wave loads of different strengths are compared, and the influence of the change of liquid filling method on the protection effectiveness of the multicell liquid cabin structure is discussed. The results show that: under the blast impact load, the panels near the blast and the panels far from the blast of the fully filled liquid cabin structure show bending deformation in line with the direction of the blast, while the rest of the outer panels are bent and deformed to the outside of the structure. The deformation morphology of the partially filled liquid cabin structure is related to the filling position. When the structure is completely filled with liquid, the anti-explosive performance of the concave multicell liquid cabin structure is better than that of the conventional liquid cabin structure. When the structure is partially filled with liquid, the anti-explosive performance of the concave multicell liquid cabin structure, which is partially filled with liquid near the explosion, is better than that of the conventional liquid cabin structure, and the anti-explosive performance of the concave multicell liquid cabin structure, which is partially filled with liquid away from the explosion, is inferior to that of the conventional liquid cabin structure.
  • KOU Farong, HE Jiajie, LI Mengxin, XU Jia’nan, WU Dapeng
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 303-311.
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    In order to improve the poor adaptability of dynamic performance and energy regenerative characteristics of active suspension on different road levels, an adaptive fuzzy control of electromagnetic hybrid suspension based on road level recognition was designed. The BAS-BP road recognition model was established by optimizing the neural network weight threshold with BAS algorithm. An adaptive fuzzy PID controller is designed. Three objective functions are designed for different pavement levels and the main dynamic feedback adjustment theory domain is introduced. The dynamic performance and energy regenerative characteristics of suspension were analyzed by simulation and bench test was carried out. Simulation results show that: Compared with fuzzy PID control, the root mean square of sprung mass acceleration of the suspension system with adaptive fuzzy control is reduced by 13.28% and 13.84% on grade A and B road surface, and the root mean square of dynamic load of the tire on grade B, C and D road surface is reduced by 9.09%, 16.07% and 15.54% respectively, and 42.8W vibration energy recovery is achieved. The experimental results show that, compared with the simulation analysis, the relative errors in time domain and frequency domain are within 16%, which verifies the correctness of the simulation results and the practicability of the system.
  • BAI Hua1, LIU Boxiang1, JI Naichuan2, LI Jiawu1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 312-320.
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    In order to ensure the flow field around the segment model to meet the two-dimensional flow characteristics, it is necessary to set end plate to reduce the influence of the end effect. In the past, the setting of end plate size was mostly based on experience and lack of quantitative basis, Therefore, a method was proposed to estimate the reasonable size of the two-dimensional end plate of the segmental model. The two-dimensional flow field of the test section was calculated by numerical simulation, and the dimensionless dynamic pressure difference distribution function F(x,y) at different positions of the section was obtained. At the same time, the correction coefficient K was introduced to consider the influence of position spacing on the end effect. On this basis, the parameters P(x,y) which effected the influence of the three-dimensional flow around the (x,y) position on the aerodynamic force of the model was proposed. The larger the value is, the more serious the influence of end flow is. According to the results of wind tunnel test and numerical simulation, when the width direction of the model is 10 and the height direction of the model is 15, the size of the end plate can ensure that the end effect is completely eliminated. From this value, the reasonable size of the end plate can be calculated. The effectiveness of this method is verified by wind tunnel test. The method in this paper can provide a reference for the quantitative determination of the reasonable size of the binary end plate.
  • LIN Yun, GUO Yu, CHEN Xin
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(2): 321-328.
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    In the vibration signal of planetary gearbox, the gear related vibration component usually has relatively high energy. At the same time, bearing slip will make it difficult to obtain the characteristic frequency of the vibration component corresponding to planet bearing fault. Therefore, a fault extraction method of planet bearing based on parameter optimized Maximum Second Order Cyclostationary Blind Deconvolution (CYCBD) is proposed. Aiming at the problem that it is difficult for CYCBD to obtain the cycle frequency and filter length under the condition of bearing slip, the improved envelope spectrum fault feature ratio (IFFR) index is used as the fitness function of particle swarm optimization algorithm to automatically obtain the actual cycle frequency and optimize the filter length in CYCBD algorithm, and the parameter adaptive CYCBD algorithm is used to enhance the impact of bearing fault. The square envelope spectrum of deconvolution results reflects the bearing fault characteristics, so as to extract the fault characteristics accurately. The simulation and experimental results show that this method can effectively extract fault features of planet bearing.