15 March 2024, Volume 43 Issue 5
    

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  • HAN Yan1,2,BU Xiumeng1,WANG Lidong1,2,3,LUO Ying1,2,LI Kai3
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 1-11.
    Abstract ( 331 ) Download PDF ( 109 )   Knowledge map   Save
    Track unevenness is one of the primary sources of excitation that induces coupling vibrations in the vehicle-bridge system. The sensitive wavelength of the coupling vibration in the system has been identified, which holds significant reference value for line management. Firstly, a spatial model of the high-speed maglev train-track beam coupled system is established. In this model, the maglev train is simulated as a multibody dynamic model with 537 degrees of freedom, while the track beam is simulated as a spatial finite element model. The two are coupled through the magnetic track relationship based on PD control theory. Secondly, the Shanghai high-speed maglev is used as the research background, and a 5-car marshalling train crossing a 20-span simply supported girder bridge is selected as the calculation condition to verify the correctness of the model by comparing it with the measured results. Finally, considering the uneven excitation of track harmonics, the effects of different combinations of track unevenness in various directions, different amplitudes of track unevenness, and different vehicle speeds on the sensitive wavelength of dynamic response and ride stability of trains and bridges are discussed. The results indicate that the coupling of lateral and vertical vibrations in the maglev-bridge system is weak. At a design speed of 430 km/h, the sensitive wavelengths of the car body in vertical, roll, and pitch accelerations are 140-180 m, 60-100 m, and 120-160 m, respectively. The sensitive wavelengths of the car body in lateral and yaw accelerations are greater than 200 m. Resonance in the body roll, yaw, lateral, pitch, and vertical directions can be triggered at wavelengths of 80 m, 105 m, 115 m, 140 m, and 160 m, respectively. The response amplitudes of the car body and main beam are generally linearly related to the amplitude of track unevenness. When the amplitude of track unevenness is 1 mm, the peak roll acceleration of the car body does not change significantly with vehicle speed, while the peak accelerations in the other four degrees of freedom decrease with increasing vehicle speed. The vertical acceleration amplitude of the main beam increases linearly with vehicle speed. The lateral and vertical Sperling indicators of the car body indicate that the Sperling index of the car body is less than 2.5, indicating good ride stability for the maglev vehicle.
  • CHEN Tianyu1,2,MA Cunming1,2,DUAN Qingsong3,XIANG Hongxin1,2
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 12-19.
    Abstract ( 183 ) Download PDF ( 74 )   Knowledge map   Save
    The vortex-induced vibration of the bridge is mainly affected by the aerodynamic shape, structural dynamic characteristics and flow characteristics of the beam section. The long-span bridge is a typical wind-induced sensitive structure, so it should be treated carefully in the design. This paper studies the vortex-induced vibration performance a long-span combined highway and railway truss bridge which contains two separated decks. The vortex-induced vibration of the girder was studied by wind tunnel experiment in XNJD-1 reflux series wind tunnel. Computational fluid dynamics (CFD) simulations were carried out, and a series of aerodynamic control measures were adopted to suppress the VIV of the truss girder. The spanwise periodic perturbation method is introduced into the VIV control of the truss girder. And the effect of the L-shaped baffle and the wavy wind fairing on the VIV is verified. Finally, the influence of the geometric parameters of the wavy wind fairing on mitigating VIV were investigated through wind tunnel experiments. The results show that the suppression effect of the wavy wind fairing is sensitive to the amplitude, and increasing the amplitude can effectively suppress the VIV of the girder.
  • JIANG Huimin1,YANG Qun1,2,3,FAN Jiahao1,LIU Xiaobing1,2,3
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 20-30.
    Abstract ( 122 ) Download PDF ( 143 )   Knowledge map   Save
    To investigate the mean aerodynamic force characteristics of two rectangular cylinders arranged inline, the mean drag coefficients and the mean lift coefficients of the two rectangular cylinders with a width-to-height ratio of 1:4 were tested and analyzed by rigid model pressure measurement wind tunnel tests at various incidence angles and different spacing ratios. The test results were compared with those of a single one. In addition, the interference mechanism of the mean aerodynamic force coefficients of the two rectangular cylinders arranged inline was further revealed by analyzing the mean wind pressure distribution. The incidence angle α varies from 0° to 90° and the spacing ratio P/B (the ratio of the center-to-center distance of the two rectangular cylinders to the breadth of the cylinders) ranges from 1.2 to 8.0. The results show that the mean drag coefficients of the two rectangular cylinders can be divided into two categories: 0°≤α≤30° and 30°<α≤90°. The mean lift coefficients of the upstream rectangular cylinder can be classified into 0°≤α≤75° and 75°<α≤90°, and that of the downstream rectangular cylinder can be diversified into 0°≤α≤20° and 20°<α≤90°. The amplifying effect of the mean aerodynamic force coefficients is mainly reflected in the upstream rectangular cylinder, where the maximum mean drag coefficient is 1.5 times that of a single rectangular cylinder and the maximum mean lift coefficient is 2.1 times that of a single one.
  • LI Chengming1,WANG Qiming1,3,ZHU Ruihu2,3,HU Yan1,WANG Bochun1
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 31-40.
    Abstract ( 143 ) Download PDF ( 56 )   Knowledge map   Save
    Waves are long-term and significant external excitations for the pile foundation in high-piled wharves. Identifying damage in pile foundations under wave excitation is crucial for constructing health monitoring systems. The dynamic response under wave excitation exhibits multi-type aliasing, narrow-band and non-stationarity, which pose challenges for accurate damage identification using existing methods. To address the above issues, an automatic reconstruction method based on Complete Ensemble Empirical Mode Decomposition with Adaptive Noise and K-means++ was proposed to extract damage sub-signals. Then, a novel composite energy damage index was constructed to enhance the sensitivity and robustness of damage identification under small wave excitation. Furthermore, wave excitation experiments were conducted on a high-piled wharf model under various damage conditions to verify the effectiveness of the new method in damage identification. The results show that the composite energy factor combines both energy and phase advantages, which can precisely identify the damage’s presence, location and severity.
  • TAN Jian1,ZHANG Li2,WANG Chong1,ZHANG Yulong3,ZHANG Yu1,DUAN Menglan1
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 41-51.
    Abstract ( 149 ) Download PDF ( 21 )   Knowledge map   Save
    The intricate and ever-changing marine conditions give rise to the phenomenon of large-caliber cold water pipe forced vibration. This study aims to investigate the underlying mechanisms of cold-water pipe vibration response under uniformly distributed loads, linearly varying hydrostatic pressure, concentrated loads, and periodic loads. By employing the Euler-Bernoulli beam theory, a dynamic control equation for the pipeline is established. Leveraging the generalized integral transformation method, an analytical solution for the forced vibration of the system is obtained. A comparative analysis with the Differential Quadrature Method (DQM) and the Differential Transform Method (DTM) confirms the high accuracy and effectiveness of this approach. Furthermore, the influences of internal flow, viscoelastic dissipation coefficient, damping ratio, and mass ratio on the vibration characteristics of the pipeline are analyzed. The results indicate that flutter occurs when the vibration frequency corresponding to the internal flow velocity approaches the natural frequency of the pipeline. Increasing the viscoelastic dissipation coefficient, damping ratio, and mass ratio sequentially diminishes the inhibitory effect on lateral displacement. Significantly, altering the excitation position and frequency can induce notable changes in the lateral displacement of the pipeline. The findings of this research provide valuable guidance for the initial design of cold-water pipe.
  • YUAN Xiaoming1,2,WANG Weiqi1,2,PANG Haodong1,2,ZHANG Lijie1,2
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 52-61.
    Abstract ( 148 ) Download PDF ( )   Knowledge map   Save
    Aiming at the parametric vibration caused by the pressure pulsation of the driving hydraulic cylinder of the electro-hydraulic 3-UPS/S parallel stabilization platform, the parametric vibration equation is established and the first order approximate solutions of the primary resonance response and the combined resonance response are solved by using the multiscale method. The response characteristics of primary resonance and combined resonance and the variation of vibration amplitude in the initial workspace are analyzed. Finally, the parametric vibration model is validated by using the Runge-Kutta method and modal tests. The results show that the maximum error between the numerical and theoretical solutions is 4.2%, and the maximum error between the theoretical and experimental values of natural frequencies is 4.66%, which can verify the correctness of the parametric vibration model.
  • SUN Jiedi1,2,ZHAO Binji1,WEN Jiangtao3,SHI Peiming3
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 62-71.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To address the problem of the severe shortage of label samples for intelligent bearing fault diagnosis in practical applications, this paper proposes a data enhancement method combining compressed sensing, dictionary learning and transfer for small sample fault diagnosis research. Firstly, the source domain label data is used to generate a specific source domain dictionary through wavelet packet dictionary learning and optimization processing, and the shared representation coefficients are obtained to acquire the intrinsic fault information; then a small amount of target domain signals are used to fine-tune the shared representation coefficients, and the source domain dictionary is updated to generate a transfer dictionary; finally, a large number of new samples with target domain characteristics are generated through the representation coefficients and transfer dictionary to achieve data enhancement. The data augmentation algorithm is validated using a commonly used deep fault diagnosis network, and the results show that the signals generated by the method have valid information about the fault and can be used for model training and identification with good diagnostic performance. The proposed method provides a new idea for the small sample fault diagnosis.
  • XIA Yankun,LI Xinyang,REN Junjie,KOU Jianqiang
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 72-81.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Due to long-time high load operation, the insulation performance between turns of the stator winding of permanent magnet synchronous motor (PMSM) is prone to decrease, resulting in inter-turn short circuit. At this moment, the vibration intensity of the motor will change. In response to this phenomenon, this study proposed a CEEMDAN-HT nonlinear signal analysis method that combined complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) and hilbert transform (HT) and utilized it for extracting fault features from vibration signal. Firstly, the vibration signal was decomposed using CEEMDAN algorithm to obtain a series of intrinsic mode functions (IMF), and the variance contribution rate in principal component analysis was applied to distinguish the IMF component containing fault feature information. Secondly, the IMF with high contribution rate was analyzed using HT, and the main fault features were obtained by presenting time, instantaneous frequency, and amplitude using three-dimensional joint time-frequency diagram. Finally, a short circuit fault simulation of motor was conducted using ANSYS finite element software, and a short circuit fault experimental platform was constructed. By comparing and analyzing the finite element simulation results and experimental results, the effectiveness and accuracy of the method proposed in this study were verified.
  • WANG Zhaodong1,WANG Zifa2,3,LI Zhaoyan2,MIAO Pengyu1,WU Luyuan1
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 82-93.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Two liquefaction discrimination methods are proposed. The first method is to establish a machine learning model with sand liquefaction prediction function based on 519 sets of static penetration test data from the New Zealand Geotechnical Database (NZGD). First, three machine learning classification models, namely, Support Vector Machine (SVM), Random forest (RF), and XGboost (eXtreme Gradient Boosting (XGB), are established. After super parameter optimization using GridSearchCV, the performance of the model is evaluated using the overall accuracy (OA), accuracy (P), recall (R), and F1 values, Conduct model validation on historical liquefaction data and compare the results with domestic and foreign methods. The second method is based on historical earthquake damage data and uses empirical judgment to determine the initial judgment conditions for static penetration testing. The results show that Random forest can be used as a liquefaction Discriminative model with strong prediction ability. By comparing with the domestic Geotechnical investigation and the international Olsen method, Random forest with simple elements and rapid calculation can achieve the accuracy close to the above two power methods, which is a feasible liquefaction Discriminative model; In addition, based on the historical liquefaction database, the conic resistance threshold method with the limitation of liquefaction burial depth under different intensities is summarized. The accuracy rate of the method is good in the 7 intensity zone, 8 intensity zone, and 9 intensity zone through data verification. Compared with the Code for Geotechnical investigation, it has the advantages of good operability, strong interpretability, and wide applicability. The established model has strong applicability for predicting soil liquefaction, and the initial judgment conditions of static cone penetration can also serve as reference values for rapid liquefaction discrimination. The combination of the two methods can provide good reference value for scientific research and engineering construction.
  • ZHOU Hongdi,HUANG Tao,LI Zhi,ZHONG Fei
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 94-102.
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    The distributions of different domains under varying working conditions are often complex, which will lead to the challenges of mitigating feature distortion and divergence during data alignment in the original space. In this study, a rolling bearing fault diagnosis method based on Manifold Feature Domain Adaptation (MFDA) is proposed. An intermediate domain whose distribution is similar with source domain is firstly generated with unsupervised techniques. Then, a common space connected with the source, intermediate, and target domains is constructed. Meanwhile, the local generative discrepancy metric is adopted to preserve the local manifold geometry of the data within the subspace, which can prevent the distortion and divergence during alignment process. The maximum mean discrepancy is adopted to align the intermediate and target domain and minimize the distributional difference of those two domains, the correlation between local and global structures of data is consequently ensured. Finally, the learned features are utilized for cross-domain fault identification of rolling bearings using the least squares method. Three datasets of rolling bearing is utilized, and the experimental results demonstrate the effectiveness of proposed method in mitigating feature distortion and divergence. Furthermore, the proposed method exhibits exceptional generalization performance compared with other intelligent recognition algorithms.
  • XIA Zhongxian1,WU Yuhou1,BAO Zhigang1,FAN Yongzhong2,YAN Haipeng3,SUN Jian1
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 103-109.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To investigate the effect of cage on vibration characteristics of full ceramic ball bearings under cryogenic condition, theoretical and experimental research is carried out for silicon nitride full ceramic ball bearings under cryogenic condition, and vibration signal characteristics of full ceramic ball bearings equipped with cages of different materials are tested and analyzed. The results show that the vibration characteristics of the cage is similar to the contribution characteristic frequency of its stress state, which are mainly composed of the characteristic frequency of cage fc, the frequency doubling of ceramic ball characteristic frequency fb, the frequency doubling of inner ring characteristic frequency fi and the characteristic frequency components of cage and inner ring coupling. The vibration velocity of full ceramic ball bearings equipped with polymer matrix composite and bakelite cage is lower than that of full ceramic ball bearing equipped with carbon fiber composite cage, while the kurtosis value of the full ceramic ball bearing equipped with carbon fiber composite cage is lower than that of the full ceramic ball bearings equipped with bakelite and polymer matrix composite cages. In other words, carbon fiber composite is superior to bakelite and polymer matrix composite in signal stability and fault probability reduction of full ceramic ball bearing. The research results have a certain reference value for the selection of full ceramic ball bearing cage under cryogenic condition.
  • WANG Meng1,2,SHI Xun1,2,4,YANG Weiguo1,2,GE Jiaqi3,MA Botao3,ZHANG Mansheng3,LIU Pei1,2
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 110-120.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to optimize the seismic effect of the support for fixing the figurines in the museum collection, the typical seismically vulnerable figurine replicas (warrior figurines and Tang Sancai figurines) with different sizes and physiques were selected. The shaking table tests on the seismic system of the replicas and optimized combined measures (supports and fasteners) were carried out. The key optimization parameters affecting the movement of the replica and the interaction behavior between the replica and the support were obtained, and the seismic effectiveness of the combined measures for fixing the large figurine relics was verified. The numerical model of the interaction system between the replica and the combined measures was established. Through the parametric analysis, the impact of the gap between the support and the relic, the impact of filling the gap with different types of cushion on the dynamic responses of the figurine, the interaction between the replica and the fixation measures, and the minimum support size for the effective fixation of the figurine by independent support/combined measures were obtained, which provided the necessary basis for the optimal design of the fixation measures taking into account the principle of safety and minimum intervention. The results show that the combined measures effectively reduce the dynamic responses of figurines and improve the fixation effect compared with independent supports. In order to ensure the safety of figurines, it is recommended that the gap between the support and the figurine should be no more than 5mm. The measures of filling rubber pads and silicone pads in the gap could decrease the interaction force between figurine and the support by 50%~75% and effectively prevented the local damage of figurines. When the size of the figurine exceeded a certain limitation, the independent support is no longer applicable, as a result, the combined measures of the support and the shaped fastener are suggested.
  • LIU Xiuping1,WANG Tao1,YANG Kehuan2,FENG Yu1,HAN Wanshui1
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 121-130.
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    To study the vibration reduction effect of Tuned Mass Damper (TMD) on bridge structures subjected to vehicle loading and reveal the excitation mechanism of TMD under moving vehicles, a multi-degree-of-freedom structural TMDs control method based on modal kinetic energy evolution was proposed. Optimal design parameters and installation locations for TMDs were determined. Considering the generality of dynamic solution for bridge finite element models, a vehicle-bridge-TMDs dynamic coupling analysis system was established using the BDANS software, a three-dimensional bridge dynamics analysis tool. Taking a classic case of a simply supported beam with a single-degree-of-freedom moving mass-spring system as the research object, the vibration characteristics of the vehicle-bridge-TMDs system were analyzed. An engineering example of a non-navigable bridge in a deepwater area with wind-resistant TMDs was studied to analyze the damping effects and mechanisms of TMDs on vehicle-induced vibrations. The research findings indicate the following: The amplitude of TMDs travel is positively correlated with its damping effect, indicating that larger travel amplitudes result in better attenuation of vehicle-bridge dynamic effects-induced vibrations. Installing TMDs can significantly increase the equivalent damping ratio of the structure, meeting the engineering requirement of an equivalent damping ratio greater than 1% and improving the stability of bridge structural vibrations. In certain conditions, TMDs can reduce the vertical displacement impact caused by moving vehicles, with a maximum reduction of approximately 3%. TMDs have a suppressing effect on the peak transient accelerations of both the vehicle and bridge subsystems, especially on the vertical acceleration of the bridge structure. The root mean square (RMS) value of the vertical acceleration at the midspan of the bridge decreases by approximately 20% after installing TMDs. For long-span steel box girder bridges, compared to smaller impact effect of moving vehicles, structures with first-order vertical bending mode exhibiting adjacent span anti-symmetrical characteristics are more easily excited by TMDs, resulting in better vibration attenuation of the bridge structure while vehicles move through.
  • ZHANG Ke1,2,ZHANG Liqi1,WANG Zhan1,GAO Liuwang1
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 131-138.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to investigate the dynamic characteristics of full ceramic angular contact ball bearings with ball slippage, a contact model between the roller and the outer ring of the bearing was established, and the contact parameters under sliding condition were calculated. On this basis, a dynamic model of full ceramic angular contact ball bearing considering the ball slippage was established. The vibration characteristics and periodic rules of the bearing system were analyzed by the calculation results of the model. According to the calculation results of the model, the contact deformation and contact area of balls during sliding motion increase with the increase of the load. However, the contact deformation is much smaller than that under normal contact, and the contact area is larger than that under normal contact. A bearing rotor test platform was set up to carry out vibration test. The average error between the vibration amplitude of the full-ceramic bearing and the results calculated by the model is only 0.68% under experimental conditions, which proves the accuracy of the model. This study provides a theoretical basis for the study of contact mechanism and dynamic characteristics of full ceramic angular contact ball bearings.
  • CHANG Mingyu1,2,SHEN Yusheng1,2,ZHANG Xi1,2,GAO Deng1,2,LUO Yang1,2,WANG Haokang1,2
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 139-148.
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    Aiming at the demand for monitoring model box displacement, surrounding rock movement, and tunnel lining deformation in vibration table experiments, a self-correction technology for tilted images is proposed by combining Yolo-V2, improved Canny edge detection, Hough transform, and tilt correction technology. The technology corrects the tilted image to an image where the camera axis is perpendicular to the motion plane of the measuring point for analysis, solving the problem caused by the limitations of the size of the vibration table and the tunnel lining model, which makes it difficult to set up the camera position vertically above the motion plane of the measuring point for shooting, affecting the accuracy of the subsequent processing results, and improving the field of use for target tracking algorithms in structural displacement and deformation monitoring. At the same time, the tracking of the corrected image is completed through the kernel correlation filtering technology to form a complete monitoring system. The system was used for the seismic action test of a fault-crossing tunnel's toughened structure with earthquake resistance and anti-seismic performance. The displacement of the model box, the movement of the surrounding rock, and the deformation of the tunnel lining were monitored. The reliability of the system was verified by comparing the data collected using high-precision wire-type displacement meters and displacement sensors. The results show that when there are markers at the monitoring points, and after correcting the acquired results for the tilted image, the 2-norm of the monitoring results compared with the displacement sensor is less than 0.005; when it is difficult to post markers, the precision of the tracking of the surface feature on the structure reaches 97.5%. The experimental results prove that the automatic correction technology for tilted images has high reliability in tracking images without markers for non-standard labels.
  • HE Dan1,2,QUAN Wei1,TANG Mingjun3,LIU Hui1
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 149-158.
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    Aiming at the difficult problem that the coupled impact feature extraction and separation in fault diagnosis, a method of adaptive extraction and separation of impact features based on multiscale morphological filtering (MMF) and recursive differencing was proposed. Firstly, the CMFH morphological operator suitable for impact feature separation is selected from the typical combinatorial operators using EA index and frequency response characteristic analysis; Secondly, the periodic impact features are extracted using the CMFH morphological operator and the weighted harmonic-to-noise ratio (WHNR) index; Then, the SOSO technique is used to suppress harmonic interference and white noise to further enhance the periodic impact features; Finally, the cyclic filter is constructed by iterative difference idea to extract and separate the periodic impact features at multiple scales. The simulation data and the analysis results of the traction motor bearing fault data show that the proposed method is better than the latest blind deconvolution (CYCBD) method and the classical spectral kurtosis method in extracting periodic impact under random impacts and harmonic disturbances.
  • LI Shurong1,2,ZHANG Xin1,2,YUE Qingxia1,2,GONG Shanliang3
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 159-165.
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    To study the seismic performance of the frame underpinning joints, 5 wrap-underpinning joints under frame column were designed and constructed. The cyclic loading tests were conducted and the influence on the failure mode and seismic performance of the height of interface and interface reinforcements were studied. Finite element mode of underpinning joint was established, and the accuracy of the model was verified by comparing the simulation results with the test results. The test results and analysis results show that the seismic performance was influenced most significantly by the interface height. When the joint height is 200mm, the interface reinforcement affects the failure mode of the underpinning joint, and the initial stiffness of the underpinning joints increases with the increase of the interface reinforcement. when the height joint is 300mm, the interface reinforcement has little influence on the seismic performance of the frame underpinning joints.
  • LI Feng1,YANG Tiejun1,WU Lei2,XU Yang2,LI Wenke1,LI Xinhui1,ZHU Minggang1
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 166-172.
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    A pneumatic impact hammer was developed as force excitation for the secondary path pre-identifying of an active vibration control system for marine machine. Simulation and experimental investigations were carried out to understand its characteristics. Firstly, the thermal-mechanic coupling model of working process and impacting model of the pneumatic hammer are derived and the relationship of impact velocity, impact force and duration time are derived. Simulation and measurements of piston group working process are compared and analyzed. Then the effects of spring stiffness, viscous damper of piston and dead volume on the hammer impact velocity are discussed. Finally, impact forces from calculation and measuring are compared, the comparison of transfer functions of a flexible structure excited by the pneumatic hammer and a traditional hammer is also made. The feasibility and effectiveness of the developed pneumatic hammer are verified.
  • LIN Zhiqiang1,LUO Min1,WANG Jing2,XU Tingting1,LI Qiaozhen1
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 173-181.
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    In this paper, for the stochastic dynamic contact problem of controllable universal joint flexible pipes in elbow pipe, the elbow pipe and the controllable universal joint flexible pipes are used as research objects. Hamiltonian principle combined with multi-body system dynamics theory is adopted to introduce rigid body motion coordinate system to describe the motion constraints of controllable joint, and pipe-pipe contact model is used to describe the dynamic contact of controllable universal joint pipe and elbow pipe. Established the syphon controlled universal joint flexible pipes numerical calculation methods of contact nonlinear multi-body system dynamics. Taking the flexible drill pipe in the deviation section of ultra-short radius horizontal well as an example, the vibration characteristics of the flexible drill pipe were evaluated according to the dynamic characteristics standard of Baker Hughes, and the effects of different rotational speed and bit weight on the dynamic characteristics of the flexible drill pipe were studied. The results indicate that the transverse vibration is the main factor leading to the possible failure of the flexible drill pipe. The transverse vibration of flexible pipe decreases with the increase of rotational speed, with the increase of weight on bit.
  • YANG Yongyu1,2,LI Tengyue2,CHENG Changzheng2,ZHAO Hang1,GE Renyu1
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 182-187.
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    Orthotropic anisotropic plates are widely used in engineering structures due to the light weight and high load-bearing capacity. A method is proposed to analyze the free vibration characteristics of orthotropic anisotropic plates based on the Green's function combining and Peridynamic differential operator (PDDO). Firstly, the displacement function in the vibration control equation is assumed to be the first-order integral form with Green's function. Secondly, the linear fourth-order partial differential equations are discretized into algebraic equations in the radial and circumferential directions of the notched plate, respectively. Finally, the generalized characteristic equation of free vibration is established by constructing PDDO interpolation functions to represent the non-common discrete point displacements, which can obtain the free vibration frequency and shape to prove the accuracy of the proposed method. The influence law of the notch geometry parameters on the vibration characteristics of the structure is analyzed, which can provide support for designing of the plate and shell structure.
  • TIAN Hao1,2,3,HU Jinjun1,2,TAN Jingyang1,2,JIN Chaoyue3,LIU Mingji1,2
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 188-201.
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    The prediction model of ground motion response spectrum is the foundation of seismic hazard analysis.Here,based on 892 sets of offshore ground motion records and 4 033 sets of onshore ground motion records from Japanese K-NET network in Sagami Bay area,considering magnitude, hypocentral distance,focal depth as well as source type and site, the prediction models of peak ground acceleration (PGA) and acceleration response spectra (SAs) at 0.05-15.0 s of offshore ground motion were established. The rationality of models was verified with residual analysis and correlation analysis,and effects of source type and focal depth on response spectra were analyzed.Differences between offshore and onshore ground motion prediction models were compared.The results show that source type and focal depth affect the models’ prediction results significantly; SAs predicted using the horizontal offshore model and the long-period (T≥10 s) vertical offshore model are larger than those predicted using the onshore model,and site amplification coefficients of the horizontal model and the long-period vertical model are both larger than 1.The established model can provide a reference for establishing long-period offshore ground motion models and probabilistic seismic hazard analyses,and provide a basis for aseismic fortification of long-period offshore engineering projects. 
  • ZHAO Yang1,2,3,LIU Jinhui1,XIAO Yang1,DENG Congying1,MA Ying1
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 202-213.
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    The proposed method is based on the frequency response function (FRF) of the digital model of the structure. The modal parameters which are identified by the least square complex frequency domain method are used to modify the physical parameters derived from the lumped mass method, to establish a mathematical model consistent with the dynamic behavior of the structure. Firstly, the method is verified on the clamped-clamped beam model. Then, the fine finite element model of a 600MW large turbogenerator stator end winding is established, and the modal parameters calculated by the finite element method are compared with the measured results to verify the reliability of the model. After that, based on the FRF calculated by the finite element model and the model parameters, the physical parameters of the end winding are identified and its mathematical model is established. The results show that: 1. Compared the end winding modes identified by the least squares complex frequency domain method to the finite element results in the frequency range of 75 ~ 115Hz, the largest errors of natural frequency and damping ratio are 0.27% and 0.5% respectively which appear in the first mode. And the modal shapes are close to each other. 2. The maximum error of the natural frequency between the mathematical model and the finite element model is 0.27%, and the modal shapes are consistent. 3. The matching degree of the FRF at the measuring points between the mathematical model and the finite element results can reach 95%, and the others also can exceed 85%. This method can provide a basis for accurate modeling of large turbogenerator stator end winding dynamic characteristics.
  • YU Yang,FU Tao
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 214-222.
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    In order to study the dynamic response of the circular curve honeycomb sandwich panel with negative Poisson's ratio under low-speed impact, based on Hamilton's principle and the first-order shear deformation theory, the motion equation of the circular curve honeycomb sandwich panel with negative Poisson's ratio is derived. Meanwhile, this study applies the mass-spring model to obtain the contact force between the spherical impactor and the sandwich panel. Besides, the Navier method and Duhamel’s integral are used to solve the vibration displacement of the sandwich panel. In terms of validity verification of theoretical model, the maximum relative error between the theoretical model and the ABAQUS finite element simulation results is 4.9%, and the maximum relative error of the contact force between the theoretical model in this paper and the published re-search is 8%, which verifies the validity of the theoretical model. The influence of the unit cell parameters on dynamic response of the circular curve honeycomb sandwich panel was studied by theoretical model. The results show that the maximum lateral displacement of the sandwich panel increases with the increasing velocity of the spherical impactor. The impact resistance of the honeycomb sandwich panel decreases with the increasing of the unit cell radius or angles, when the unit cell radius increases from 5 mm to 7 mm, the impact resistance of the honeycomb sandwich panel structure decreases by 40.28%, and when the unit cell angles increase from 30° to 60°, the impact resistance of the honeycomb sandwich panel structure de-creases by 83.64%. The impact resistance of the honeycomb sandwich panel increases with the increasing of the unit cell wall thickness, when the unit cell wall thickness increases from 1 mm to 3 mm, the impact resistance of the honeycomb sandwich panel structure increases by 59.51%. By decreasing of the unit cell radius or angles, and increasing of the unit cell thickness, the impact resistance of the circular curve honeycomb sandwich panel can be improved.
  • WU Penghui1,WANG Jilei1,MAO Chenyang1,ZHAO Yan1,2
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 223-230.
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    For the bolted assembly structure with hysteresis effects, a frequency domain approach was developed for the power spectral density analysis of the random vibration response of a structure by combining the pseudo excitation method and the multi-harmonic balance method. First, for an assembly structure with random excitation, the constitutive was modeled using the Jenkins model. Second, the random excitation was expressed as a complex exponential series expansion form. Then, the extended pseudo excitation method (E–PEM) was proposed to transform the response spectral analysis into a vector operation of the pseudo response. Finally, for the constitutive computation in the frequency domain during the pseudo response solution, the time-frequency transform (AFT) was introduced to deal with it. Furthermore, convergence difficulties of the traditional Newton method were solved by converting the iterative solution problem into an optimization problem and solving it using the trust region method. The random vibration response spectral characteristics of the assembly structure were investigated by using the two-DOF model and the assembly beam model. The correctness of E–PEM was verified by comparison with Monte Carlo simulation (MCS), and some nonlinear random vibration mechanisms specific to the structure were discussed. The results show that the E–PEM in this paper provides a useful solution idea for the frequency domain analysis of random vibration of general nonlinear structures.
  • WANG Haoqi,YU Bingqian,CHEN Jun
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 231-238.
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    Human jumping load tests with 27 participants were conducted and 9985 time histories of single-jumping load cycles and their corresponding human body motion were obtained through motion capture system, which has been commonly used in the field of medical science and biomechanics. The measured jumping cycles were expressed by a 3-parameter model and a Fourier-series model with different model parameters. The human body motion and the load parameters are considered as the inputs and the outputs of a convolutional neural network, respectively. With the trained network, the time histories of the jumping cycles could be reconstructed from the human body motion. Comparison between the reconstructed and measured jumping loads shows that the features of the reconstructed ones coincide well with those of the measured ones in both the time and the frequency domain. The proposed method can serve as an indirect technique for human jumping load measurement.
  • WANG Peng,LI Danqing,WANG Heng
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 239-249.
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    For the problems of large differences in feature distribution between monitoring signals of different models of rolling bearings and small samples of fault data, which lead to low accuracy of bearing faults, a rolling bearing fault diagnosis algorithm based on improved alternating migration learning is proposed in this paper. In order to give full play to the excellent feature extraction ability of convolutional neural networks (CNN) for two-dimensional data, firstly, the one-dimensional vibration signal is transformed into a two-dimensional image and input to a deep convolutional neural network for learning; secondly, in order to reduce the difference of feature distribution between the source and target domain data, an improved alternately transfer learning (IATL) is proposed to calculate the CORAL loss function and maximum mean discrepancy (MMD) loss function between domains alternately, and back propagate to update the weights and bias parameters of each layer of the network, in order to achieve migration adaptation of bearing characteristics under variable operating conditions, across bearing types and small failure sample conditions; Finally, the Softmax function is used in the fully connected layer for fault diagnosis of the target domain data. In order to verify the effectiveness of the proposed algorithm, a migration experiment is conducted using rolling bearing dataset from Case western reserve university (CWRU). The results show that the algorithm effectively reduces the difference of feature distribution between domain data and has higher fault classification accuracy when compared with algorithms such as calculating only CORAL loss function and MMD loss function.
  • HU Haowen1,2,CHEN Denghong1,2,WANG Qianfeng1,2,HU Jilei1,2,LUO Huan1,2
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 250-259.
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    Stress intensity factors (SIFs) are important parameters in predicting the initiation and propagation of cracks in structures subjected to loads. The semi-analytical scaled boundary finite element method (SBFEM) combines the advantages of finite element and boundary element method, and without local mesh refinement around crack tips or regions existing stress singularities. The stress intensity factors can be directly extracted. Within the framework of the scaled boundary finite element method in evaluating stress intensity factors, random parameters are introduced for Monte Carlo simulation (MCs), a novel uncertainty quantification (UQ) analysis based on Monte Carlo simulation is proposed in this manuscript. Unlike direct Monte Carlo simulation, singular value decomposition (SVD) is used to construct lower order subspaces to reduce the degree of freedom of the system. Radial basis function (RBF) is used to approximate the subspaces and obtain new structural responses through linear combinations of subspaces, achieving fast uncertainty quantification analysis based on MCs. Considering the effects of structural shape parameters and material property parameters on stress intensity factors under different load conditions, an improved Monte Carlo simulation is used to calculate the statistical characteristics of stress intensity factors and quantify the impact of uncertain parameters on the structure. Finally, the accuracy and effectiveness of the algorithm proposed in this paper are verified by several examples.
  • ZHANG Fengmin,ZHANG Xiaozheng,ZHOU Rong,ZHANG Yongbin,BI Chuanxing
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 260-267.
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    Most of the current compressive sensing-based equivalent source method for near-field acoustic holography utilizes a single measurement vector model with single frequency processing for sound field reconstruction, but this model usually suffers from poor noise robustness and insufficient reconstruction accuracy. In fact, noise sources often have broadband characteristics, and the equivalent source strengths of different frequencies at the same location are grouped together to exhibit joint sparse characteristics, which can improve the reconstruction performance if the joint sparse characteristics of the source strengths are fully utilized. Therefore, the near-field acoustic holography based on multi-frequency jointly-sparse Bayesian learning equivalent source method is proposed in this paper. In this method, a near-field acoustic holographic model based on multi-frequency equivalent source method is first constructed using multi-frequency co-processing, then the joint sparse constraint is imposed on the equivalent source strengths and they are solved by the jointly-sparse Bayesian learning method. Compared with the conventional near-field acoustic holography based on single-frequency equivalent source method, the proposed method can obtain higher reconstruction accuracy and better noise robustness. The superiority of the proposed method is verified by simulations of monopole sources and an experiment of two small speakers.
  • CHEN Junsheng,YAO Zhenqiang,TANG Zhenrong
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 268-272.
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    The contact model of the bearing rolling joint was established based on Hertz contact theory. The finite element model of turret grinding carriage of the compound grinding machine was established in ABAQUS finite element analysis software, in which model, spring damping element was used to replace the bearing roller joint. and the modal analysis of the turret structure was carried out. The modal test and analysis of turret structure are carried out using LMS structure test system. The experimental results show that the finite element modal analysis using spring damping element to simulate the rolling joint of bearing is consistent with the dynamic experimental results, which verifies the feasibility of the method. The replacement of bearing by spring damping element can reduce the difficulty of modeling and provide a reference for the optimization of wheel rotation frequency and turret structure.
  • JIANG Li1,LIU Zhen2,MA Xingliang1
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 273-282.
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    Near fault ground motion is a special type of ground motion that contains high energy velocity pulses, with long periods, strong destructiveness, and concentrated energy. Compared to single tower super high-rise buildings, multi tower super high-rise buildings have more complex forces, longer natural vibration periods, easier input of velocity pulse energy into the structure, and may cause significant differences in response to each tower. However, no corresponding provisions have been issued in the seismic code for such special cases. Taking a three tower super high-rise building as an example, taking various near fault and non near fault ground motions and high energy velocity pulses as ground motion inputs, seismic time history analysis is conducted using large-scale finite element software, and seismic vulnerability analysis is conducted for the main tower and auxiliary tower structures with inter story displacement angle and maximum displacement as the main analysis objects. The results show that the example structure can meet the requirements of "no damage due to small earthquakes, no repair due to moderate earthquakes, and no collapse due to large earthquakes" under various earthquake actions; However, the response of near fault ground motions to structures is much greater than that of non near fault ground motions; Comparing the damage probabilities of various damage states, near-fault ground motions have an average increase of 11.79% compared to non near-fault ground motions. Further analysis of high energy velocity pulses reveals that velocity pulses are an important factor causing structural damage in near-fault ground motions, and smaller velocity pulses may cause more severe structural damage to the main tower.
  • CHAI Jiangshuai,LUO Qing
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 283-291.
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    This paper addresses the analytical methods of coupled micro-vibrations of spacecraft. Coupled models of micro-vibration source and supporting structure are derived through dynamic equilibrium relationship, Dynamic Mass Method (DMM), and mechanical impedance theory, respectively. The application range of the traditional DMM is discussed and analyzed. The results indicate that traditional DMM may lead to significant discrepancy in the relatively lower frequency range during coupled micro-vibration analysis, and it is only suitable for cases that when the micro-vibration source’s mass is much smaller than that of the supporting structure. Therefore, a modified DMM is proposed based on mechanical impedance theory. Using the modified DMM, a coupled dynamic model consists of the reaction wheel and spacecraft is developed, with a particular focus on the treatment of gyroscopic effects. Then, coupled dynamics of the reaction wheel and spacecraft structure are analyzed and impact of gyroscopic effects are investigated. The proposed modified DMM can provide an analytical tool for both coupled micro-vibration analysis of spacecraft and ground tests.
  • SHI Wenhui1,YUE Shuai1,LIU Zhou2,XIAO Yuzhi3,DU Zhonghua1,LIU Zhi2,GAO Guangfa1
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 292-301.
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    Aiming at the impact on the satellite platform during the launch of the pyrotechnic device, a new launch buffer structure using an aluminum honeycomb was designed. Then the internal ballistic model of the pyrotechnic device and aluminum honeycomb crushing model was established through the closed bomb tests of gunpowder and the quasi-static tests of aluminum honeycomb. Then the launch recoil model was found on this basis. And the effects of the charge of gunpowder and the inner diameter of aluminum honeycomb on the recoil characteristics were studied. The results show that when the powder charge increased by 0.3 g, the average recoil increased by 1.95%, the velocity of the mass block increased by 5.10%, the recoil displacement increased by 7.64%, and the recoil duration decreased by 10.3%. When the inner diameter of the aluminum honeycomb decreases from 148 mm by 1 mm and 2 mm, respectively, the average recoil increases by 4.06% and 9.08%, the velocity of the mass block increases by 0.22% and 0.54%, and the recoil displacement rises by 3.38% and 15.24%. And the reasonable selection of the above parameters can effectively reduce the launch recoil and ensure the launch performance of the mass block.
  • WANG Shuhan1,2,YANG Haisheng1,TANG Rui2,LUO Bin2,YANG Xiaomin1,DENG Si’er1
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 302-314.
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    Rolling bearings in aero-engine spindles are often used in conjunction with Elastic Ring Squeeze Film Damper (ERSFD) in order to reduce system vibration. Based on rolling bearing dynamics theory and hydrodynamic control equations, the dynamics analysis model of cylindrical roller bearing coupled with ERSFD is established by using the Gear stiff integral algorithm with variable step (GSTIFF), and the vibration characteristics and slip rate of cylindrical roller bearing cage with ERSFD on the outer ring are studied. The results show that ERSFD can improve the stability of cylindrical roller bearing cage compared with the cylindrical roller bearing without ERSFD assembly. Too large or too small number and width of the elastic ring bosses are not conducive to the stability of cylindrical roller bearing cages, and suitable number and width of bosses need to be selected. Radial load and rotational speed have significant effects on the stability of cylindrical roller bearing cage with elastic ring squeeze film damper. Harmonic number of cage vortex frequency decreases with the increase of radial load, and its corresponding amplitude decreases; harmonic number of cage vortex frequency increases with the increase of rotational speed, and its corresponding amplitude increases.
  • ZHANG Rongfei1,2,SUN Wei1,2,LUO Haitao3,ZHANG Hui1,2
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 315-327.
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    It is difficult to suppress the vibration of the solar wing windsurfing in the space environment, so it is very significant to study the vibration reduction of the solar wing windsurfing. The double-lap bolted thin plates is used to simulate the unfolding state of the solar wing windsurfing, and the method of vibration suppression by attaching constrained layer damping (CLD) is studied. A semi-analytical dynamic model of the double-lap bolted thin plates with "H-type" CLD is established, including: the stress-strain relationship of CLD is derived by using the principle of interlaminar shear deformation, and the damping characteristics of the viscoelastic layer are characterized by complex modulus; considering the influence region of bolts, the stiffness, damping, and mass characteristics of the joint of the double-lap bolts are simulated by using compound spring element and modified mass; the orthogonal polynomial is introduced as the displacement admissible function, and the dynamic equations of bolted thin plates with "H-type" CLD is established by using Lagrange equation and Hamilton principle. An example study is carried out, and the experimental system is established to prove the rationality of the semi-analytical model of the composite structure in solving the natural characteristics and vibration response parameters. Moreover, the results of both the experiment and the semi-analytical model show that the “H-type” CLD has a vibration reduction effect on the double-lap bolted thin plates. Finally, based on the semi-analytical model of the model, the influence of the attaching area and the thickness of the CLD on the vibration reduction effect of the double-lap bolted thin plates is analyzed
  • JIANG Wei1,2,ZHANG Ming1,2,HU Xiaohang1,2,ZHU Xin1,2,TANG Liming1,2
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 328-337.
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    In this paper, a two-wheel strut landing gear was taken as the research object to study the low-frequency vibration induced by aircraft brakes. Firstly, a complete six-degree-of-freedom mathematical model of aircraft landing brake skid was established, and the model was built in Simulnk to analyze the influence of some parameters of brake con-trol law on chattering. Secondly, the Rms value of the center course acceleration of the axle was taken as the vibra-tion quantization index, and the combination coefficient efficiency was set as the optimization objective. The multi-objective optimization design of the hydraulic brake control system parameters was carried out based on the NSGA-Ⅱ algorithm, and the optimal solution of the Parato optimal front surface and the TOPSIS compromise of the optimi-zation variables was obtained. Finally, the vibration responses of axle center before and after optimization were compared according to the optimized design scheme, and the adaptability of the optimized scheme to different land-ing environments was tested by setting several groups of simulation conditions. The results show that the maximum reduction of the landing gear axle center acceleration Rms value after optimization can reach 14.53%, and the max-imum increase of the binding coefficient efficiency is 3.65%, which indicates that the proposed landing gear vibra-tion reduction optimization design method has good feasibility.
  • LI Xin1,CHEN Guanfeng1,QIN Xiuyun1,CHENG Qian1,PAN Rong1,2,WANG Chunjian1,ZHANG Chengbo3
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(5): 338-344.
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    During the fatigue test of compressor blades in an aviation engine on a vibration table, the high-order harmonic components appear when the harmonic excitation signal of the shaking table is transmitted through the friction interface of several tooling. When the natural frequency of the blade is close to the frequency of the high-order harmonic component of the excitation frequency, the blade will have multi-mode coupling vibration under external harmonic excitation which can be used to simulate the multi-order coupling vibration of aero-engine compressor blades. This article obtained the vibration characteristics of displacement and strain during blade coupled vibration through vibration fatigue multi-mode calibration tests and excitation tests. Numerical analysis and experimental results show that: a) the position of blade failure is consistent with the position of high stress after the superposition of coupled vibration modes; b) with the increase of frequency difference between blade natural frequency and higher-order harmonic component frequency, the vibration stress of higher-order modes decreases exponentially.