28 April 2025, Volume 44 Issue 8
    

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    VIBRATION AND MECHANICS SCIENCE
  • Engineering equivalent reduced modeling method and scale-down experimental verification of gas turbine rotor system
    ZHAO Runchao1, JIAO Yinghou1, LI Zhitong1, XU Yeyin2, YU Guangbin1, GUO Hongwei1, LIU Rongqiang1
    Journal of Vibration and Shock. 2025, 44(8): 1-7.
    Abstract ( 227 ) Download PDF ( 315 )   Knowledge map   Save
    Gas turbines have important applications in the fields of industrial power generation, aviation and navigation, and national defense equipment.As one of the core components of gas turbines, the rotor system directly affects the performance, reliability, and service life of the whole machine.The use of equivalent models of gas turbine shaft systems can accelerate the dynamic solution process.An engineering equivalent reduced modeling method for gas turbine rotor systems was proposed in this article based on strain energy equivalence theory, combining similar design theory to obtain a scaled rotor model with similar dynamic characteristics to the prototype.The modal characteristics of the shaft system were calculated and dynamic acceleration tests were carried out to verify the accuracy of the engineering equivalent reduced modeling method.The results indicate that the deviation of the first three natural frequencies of the established engineering equivalent model from the prototype is less than 3.71%, and the deviation of the first two critical speeds is less than 3.8%.The proposed rotor engineering equivalent modeling method has broad application prospects in the dynamic design of new gas turbine structures.
  • Nonlinear dynamic analysis and experiment in a drifter-rock contact model
    MA Wei1, 2, ZHANG Jian3, JIANG Xin4, WU Wenzhang2, LI Yelin5
    Journal of Vibration and Shock. 2025, 44(8): 8-20.
    Abstract ( 158 ) Download PDF ( 67 )   Knowledge map   Save
    The structure of a drifter was introduced in this paper.Integrated with a linear rock model, the process of drilling rock was established as a four-degree-of-freedom mechanical and mathematical model.Taking the angular frequency, amplitude and vertical offset of the hydraulic force as control parameters, the single-parameter continuation analysis was carried out, and the period-doubling bifurcation, saddle-node bifurcation and torus bifurcation were found.A comparison was made between the piston displacement and velocity data obtained from the model and experimental results.The results indicate that to make the drifter work on the period-1 trajectory, the range of angular frequency should be 2.350 0<ω<6.611 0.The range of amplitude should be 0.027 2<a<1.000 0.The range of vertical offset should be 0.046 7<b<0.212 5.The model is consistent with the experimental results.
  • Study on dynamic instability basin migration mechanism of gear system based on tooth wear inefficiency
    SHI Jianfei, HAN Chuang, WANG Yanlin, JIN Wuyin, CHEN Guolong
    Journal of Vibration and Shock. 2025, 44(8): 21-29.
    Abstract ( 120 ) Download PDF ( 93 )   Knowledge map   Save
    The mounting error of gear pair accelerates the tooth wear, and the excessive wear will aggravate the meshing vibration and nonlinear vibration of gear teeth, causing premature gear failure, resulting in serious accidents.In this regard, it is important to study the health-instability basin migration mechanism of the gear system based on the wear failure of tooth flanks, which is essential for the safe and reliable operation of gear transmissions.The actual overlap of the gear pair was calculated considering the effect of mounting error; the multi-state meshing characteristics of the gear pair were extracted by analyzing the synergistic effect of overlap and tooth flank clearance; the evolution laws of time-varying meshing stiffness, load distribution coefficient and total dynamic meshing force under the influence of installation errors were calculated and analyzed; the nonlinear dynamics model of multi-state meshing of spur gears system with mounting error was established.Based on the nonlinear dynamic meshing force and Archard wear model, the depth of tooth wear was calculated and the health domain based on tooth wear inefficiency was constructed.The effect of joint variation of tooth side gap and multiple initial values on erosion and transmigration patterns in health-instability basins was investigated using multi-initial bifurcation diagrams, meshing force time course diagrams, phase diagrams, Poincaré mapping diagrams, and domains of attraction.The results show that the mounting error reduces the overlap and meshing stiffness of the gear pair, and the incomplete bifurcation causes the coexisting multi-attractor meshing force to exceed the limit, which leads to a healthy instability in the dynamic behavior, and induces the erosion of the health-instability basin.The system is in a healthy destabilization state over most of the initial value domain when the gap is large.
    • TRANSPORTATION SCIENCE
  • Mechanical principle and experimental analysis of vehicle magnetorheological hydro-pneumatic spring
    DONG Xiaomin1, LI Pingyang1, FEI Zhenyang1, SHEN Haoyue1, PAN Zhongwen2, GUO Haiquan3
    Journal of Vibration and Shock. 2025, 44(8): 30-41.
    Abstract ( 154 ) Download PDF ( 46 )   Knowledge map   Save
    Aiming at the problem that the damping characteristics of vehicle hydro-pneumatic spring cannot be adaptively adjusted according to road and driving conditions, and it is difficult to achieve sufficient safety and comfortBased on the insufficient adaptive damping capability with the various road and running conditions for hydro-pneumatic spring in vehicles, which cannot obtain satisfactory safety and serviceability,, a design theory of semi-active magnetorheological (MR) hydro-pneumatic spring is was proposed. Based on the MR mechanism and vibration-damping theory of vehicle suspension, a novel MR hydro-pneumatic spring with two-way damping force controllability for vehicles has beenwas designed. Mechanical principle of this MR prototype is was discussed with MR valve. Considering the compressibility of liquid and gas, squeezing strengthening effect of MR fluid and local loss, the theoretical models of output damping force and elastic force are were derived. The effects of Mechanical mechanical variations ,with piston length, gap width and gas pressure, with on output mechanical properties were have been qualitatively and quantitatively analyzed based on the derived model. Comparing with the measured results of the experimental prototype, the proposed theoretical models can precisely describe the mechanical performance under various excitations. The output force increases with the increasing increase the of excitation amplitude, frequency and the applied currents. These findings provide the theory and hardware base for optimization design of MR hydro-pneumatic spring for vehicles.
  • Study on dynamic characteristics of a tandem bionic composite suspension system
    LI Zhanlong1, ZHOU Junxian1, ZHANG Zheng1, GAO Shantie2, LIU Zhiqi1, MO Haibo1, HAO Pengxiang2
    Journal of Vibration and Shock. 2025, 44(8): 42-48.
    Abstract ( 124 ) Download PDF ( 51 )   Knowledge map   Save
    In order to improve the vibration damping performance of the suspension of high-speed and heavy-duty track ATV, a series bionic composite suspension system with compact structure and strong impact resistance was designed by combining torsion bar spring and bionic "Z" shape buffer structure. Taking a single suspension system as the research object, theoretical modeling and dynamic simulation analysis are were carried out. The research shows that the static and dynamic parameters of the tandem bionic composite suspension system are within a reasonable range. Under the same road grade, the relative growth rates of RMS of vertical acceleration and RMS of dynamic deflection of tandem bionic composite suspension system decrease with when increasing vehicle speed. As the road surface quality and vehicle speed increase, the value of the vertical acceleration transfer rate (1.7% - 2.4%) of the tandem bionic composite suspension system for the vehicle body shows a downward trend; the tandem bionic composite suspension system shows a resonance peak in theduring 2-3 Hz range, avoiding the human body’s sensitive frequency range (4 to - 8 Hz), thus demonstrating excellent frequency response characteristics that meet suspension design requirements. The introduction of this system also provides new insights for enhancing the vibration damping performance of high-speed, heavy-duty tracked all-terrain vehicle suspensions.
  • Recent research progress on assessment and prediction of railway track geometric condition
    LI Zaiwei1, LIU Xiaozhou2, SHI Jie1, YIN Ziren2
    Journal of Vibration and Shock. 2025, 44(8): 49-63.
    Abstract ( 166 ) Download PDF ( 784 )   Knowledge map   Save
    The geometric condition of railway tracks is crucial for the operational safety and ride comfort of trains. Therefore, research on the analysis of track irregularities, track quality assessment, and prediction of track irregularity development is of importantsignificant practical significance. This paper reviews recent Recent research on the assessment and prediction of track geometry was reviewed in this paper, including the analysis distribution characteristics analysis of track irregularity, track serviceability assessment, and prediction of track irregularity development. The advancements and shortcomings of existing research is was discussed and future research directions of relevant topics are were analyzed. It is found that in the study of track regularity distribution, there is a need to further integrate dynamic and static track inspection data, as well as to further investigate the data feature in the sensitive and weak track sections. Regarding track quality assessment methods, time-domain methods is predominant, whilst the frequency-domain methods are still under development. Further research is needed to investigate the relationship between time- and frequency-domain indexes, and to establish a comprehensive track quality assessment scheme incorporating wavelength parameters. In terms of track irregularity development prediction, compared to ballasted tracks and conventional railways, research on ballastless tracks and high-speed railways is relatively limited, and relevant studies inadequately consider the evolution of track structural performance. Future efforts should focus on constructing predictive models that meet the requirements of maintenance work based on actual environmental and factors. 
  • Research on anti-roll performance of straddle monorail vehicle with air spring system
    ZHAO Zengchuang1, 2, YANG Tian1, REN Lihui1, JI Yuanjin1, ZHU Dongjin2
    Journal of Vibration and Shock. 2025, 44(8): 64-71.
    Abstract ( 127 ) Download PDF ( 110 )   Knowledge map   Save
    A four-point height control air spring system is used in the secondary suspension system of straddle monorail vehicle. When the monorail vehicle runs under unbalanced load, there is a pressure difference between the left and right air springs of the bogie. The anti-roll performance of monorail vehicle is obviously affected by the leveling valve and pressure-balancing valve of the air spring system. In this paper, the dynamic simulation model of straddle monorail vehicle including the thermodynamic model of air spring system was established. Firstly, the influence of the leveling valve and pressure-balancing valve of air spring system before and after opening on the anti-roll performance of the vehicle was simulated and analyzed. Secondly, the influence of the opening threshold value of pressure-balancing valve on the anti-roll performance of the vehicle was analyzed. The results show that the critical roll angle of straddle monorail vehicle with air spring system is about 50% of that without air spring system due to the influence of leveling valve; when the pressure-balancing valve is opened, the anti-roll performance of the vehicle is significantly adversely affected, and the vehicle is in an unstable oscillation state. In order to ensure the anti-roll performance of the vehicle, the opening threshold of the pressure-balancing valve should be higher than the pressure difference of the left and right air spring when the vehicle is in the critical roll angle state.
    • VIBRATION THEORY AND INTERDISCIPLINARY RESEARCH
  • Semi-analytical modeling and vibration characteristic analysis of free vibration of hard-coated thin-walled cylindrical shells in thermal environment
    ZHENG Haojie, YANG Jian, LIU Xin, DENG Yu, ZHANG Yue
    Journal of Vibration and Shock. 2025, 44(8): 72-79.
    Abstract ( 103 ) Download PDF ( 55 )   Knowledge map   Save
    This study utilizes fFinite element software was utilized in this paper to simulate the temperature distribution in the thickness direction of a cylindrical shell under real thermal field conditions. Combining this with the generalized Jacobi polynomials and the Rayleigh-Ritz method, a semi-analytical model for the free vibration of hard-coated thin-walled cylindrical composite structures in a steady-state thermal environment is was established. Using a thin-walled cylindrical shell coated with NiCoCrAlY hard coatings as an example, the vibration characteristics under a steady-state thermal field are were analyzed. The validity and accuracy of the semi-analytical model are were verified by comparing theoretical calculations with finite element results under different temperature conditions (20 ℃, 50 ℃, 100 ℃, 150 ℃, 200 ℃). Additionally, the effects of truncation number N, different temperatures, and substrate thickness on the vibration characteristics of hard-coated thin-walled cylindrical composite structures are were discussed.The Results results indicate that when the truncation number N reaches 7, more accurate vibration analysis results can be obtained. The modal loss factor increases with the circumferential wavenumber, especially under high-temperature conditions. The natural frequency decreases as the temperature rises, with the rate of decrease accelerating at higher temperatures. As the substrate thickness increases, the modal loss factor shows a decreasing trend, with the extent of decrease being more significant at higher temperatures.
  • Study on the influence mechanism of water attack angle on vortex-induced vibration of a finite-cylinder
    DUAN Derong, DAI Senliang, WANG Muhao, ZHANG Xiaoya, ZHANG Hui, YANG Xuefeng
    Journal of Vibration and Shock. 2025, 44(8): 80-88.
    Abstract ( 144 ) Download PDF ( 47 )   Knowledge map   Save
    Different working postures of finite-length cylinders in marine engineering equipment will produce different impact effects of water flow angle of attack. In order to reveal the influence mechanism of water flow angel of attack on the vortex-induced vibration response of finite-length cylinders, the three-dimensional unsteady Reynolds-averaged Navier-Stokes（N-S） equation and SST k-ω turbulence model were used. The two-way fluid-structure interaction numerical calculation of finite-length cylinders at different angles of attack was carried out, and the accuracy of the numerical results was verified by experiments. The results show that the increase of the angle of attack will aggravate the imbalance of fluid velocity on both sides of the structure, and the lift and drag will increase, and the change of the lift wasis more obvious than that of drag, which lead to the increase of the vibration response of the finite cylinder with the increase of the angle of attack. When the angle of attack increasesd from 0° to 2° and 4°, the amplitude of the free end cross flow increaseds by 7.3% and 21.2%, and the amplitude of the in-line increased increases by 6.3% and 24.6%. The vibration frequency of the in-line vortex-induced vibration was is no longer twice that of the cross-flow. Due to the existence of the free end and the fixed end, the formation and shedding of the vortex behind the cylinder were are disturbed. The larger the angle of attack, the larger the width of the wake vortex-shedding, and the larger the vibration amplitude of the finite-length cylinder.
  • Free vibration analysis of non-uniform Timoshenko beams using improved AMDM
    YAO Donghui, REN Yongsheng
    Journal of Vibration and Shock. 2025, 44(8): 89-100.
    Abstract ( 112 ) Download PDF ( 50 )   Knowledge map   Save
    The free vibration of beams can usually be modeled by differential equations.The Adomian modified decomposition method (AMDM) is a mathematical method for solving approximate analytical solutions of differential equations, which has high accuracy.However, its accuracy depends on the convergence domain and cannot converge when solving vibration problem of Timoshenko beams with cross section varying along axial coordinate in linear or non-linear form.In order to improve convergence, firstly,the shape dependent terms in the differential equations of vibration was extracted in this paper.According the convergence of the Taylor expansion of these terms, the beam was divided into several segments.AMDM was applied to each segment of the beam.Then, boundary conditions were substituted to solve natural frequencies and modal functions.This improved AMDM provides a universal method for solving the vibration problem of Timoshenko beams with cross section varying in non-linear form.The influence of factors such as taper and power of shape functions on convergence and natural frequency was investigated.Numerical results show that the method proposed in this paper is in good agreement with FEM simulation.
  • Crack propagation characteristics of rock with an interfacial layer parallel to the direction of dynamic load
    WEN Lei1, 2, FENG Wenjie1, SHI Zhaolong1, 3, YU Junhong1, LIU Lin4
    Journal of Vibration and Shock. 2025, 44(8): 101-112.
    Abstract ( 85 ) Download PDF ( 128 )   Knowledge map   Save
    The rock-like sample with an interfacial layer was taken as the research object, and the SHPB system was used to apply impact loads of different strengths parallel to the interfacial layer of the specimen. Crack propagation process was recorded by a high-speed camera system. Crack propagation path, fracture mechanism and macroscopic mechanical properties of the specimen under different positions of interfacial layer and impact strengths were analyzed. The result of researchs shows that crack initiation and propagation is not closely related to the prefabricated edge crack, but closely related to the interfacial layer under the conditions of this test. This is significantly different from the case where the load direction is non-parallel to the interfacial layer.This phenomenon is obviously different from the loading direction and non-parallel arrangement of the interface layer. When the peak value of the incident wave is small, the axial type Ⅳ tensile crack is generally displayed. With the increase of the peak value of the incident wave, the crack gradually transforms to shear crack. The greater the peak value of the incident wave, the greater the angle between the shear crack and the loading direction, and the more type III shear cracks appear. Initial failure zone generally appears on the side with high strength and elastic modulus, and the time difference of crack initiation on both sides of the interfacial layer decreases significantly with the increase of impact strength. The initiation of intergranular tensile crack is generally caused by the convergence effect of stress waves, and the obvious bend of the main crack  is generally the late local failure area. The dynamic compressive strength of rock samples shows obvious strain rate effect, and the position of interfacial layer has significant influence on the strain rate effect. The location of the initial crack, the diversity of stress field at the crack tip, and the abrupt characteristics of the crack tip velocity during crack propagation increase the uncertainty of the prediction of dynamic crack propagation path in rock samples with interfacial layers.
  • Dynamic analysis and experimental study of a multi-tagline anti-swing and positioning system for offshore slender-beam payload
    SUN Maokai, WANG Shenghai, HAN Guangdong, CHEN Haiquan, SUN Yuqing
    Journal of Vibration and Shock. 2025, 44(8): 113-123.
    Abstract ( 79 ) Download PDF ( 36 )   Knowledge map   Save
    To address the challenges of low hoisting efficiency, high risk, and difficulty in achieving accurate positioning caused by the double-pendulum phenomenon of slender-beam payloads under rough sea conditions. A ,a novel Multi-Tagline Anti-swing and Positioning System (MTAPS) has beenwas proposed. The dynamic model of the MTAPS is was established using multi-body dynamics and Newtonian classical mechanics. Experimental data indicate that the MTAPS can effectively suppress the swinging of both regular and slender-beam payload, bringing slender-beam payload to a relatively stable state in a short time. Under specified conditions, the average anti-swing reduction ratios for regular and slender-beam payload using this system exceed 90% and 85%, respectively. Additionally, dynamic simulations were conducted to compare the anti-swing effectiveness and dynamic characteristics of the multi-tagline anti-swing system with those of the MTAPS under ship motion excitation. The anti-swing device developed on the principle of anti-swing system has been applied in engineering, which provides a new idea for the rapid lifting and accurate positioning of slender-beam payload in an offshore environment.
  • Fundamental frequency maximization design of porous structures using explicit topology optimization method
    WANG Xuan1, 2, 3, SHI Yuankun2, CHEN Xiang2, YAN Kun3
    Journal of Vibration and Shock. 2025, 44(8): 124-132.
    Abstract ( 118 ) Download PDF ( 37 )   Knowledge map   Save
    Porous structures have become one of the solutions to address the challenges in dynamic design due to their unique properties and broad application prospects. In order to achieve excellent dynamic performance in porous structure design, an explicit topology optimization method based on the moving deformable bars approach iwas proposed to maximize the fundamental frequency of undamped free vibration of porous structures. The modeling and optimization of porous structures are were realized by optimizing the geometric variables of these moving bars. The bars are were mapped to a density field on a background grid to avoid the cumbersome task of grid redivision during the bar movement. A dynamic topology optimization model of maximizing the first eigenvalue for porous structures under volume ratio constraint is was established. The analytical sensitivity of the eigenvalue objective function with respect to geometric design variables is was derived in detail, and the geometric design variables are were updated using the Method of Moving Asymptotes (MMA) to achieve the optimization design of porous structures. Finally, the effectiveness and stability of the proposed method are were verified through three numerical examples, and the influence of size control and volume ratio constraint on the optimization results is was also discussed.
  • Research on data-driven topology optimization method for microstructures of acoustic-structure interaction system
    XU Jiongyang1, YU Qiuzi1, ZHANG Jialong1, CAO Xiaolong2, CHEN Haibo1
    Journal of Vibration and Shock. 2025, 44(8): 133-142.
    Abstract ( 136 ) Download PDF ( 200 )   Knowledge map   Save
    Traditional microstructural topology optimization for acoustic-structure interaction system relies on numerical methods such as the finite element method and boundary element method, which has the problems of high computational cost and long time consumption. In this paper, a data-driven topology optimization method for the microstructures of acoustic-structure interaction system iwas proposed to overcome the problems. In this method, the density distribution of microstructures is was used as the feature, and the system response and sensitivity values are were used as labels to construct a dataset to train the artificial neural network,  respectively, and the nonlinear mapping relationships between the distribution of microstructures and the response and /sensitivity values are were established. The response and sensitivity calculation part are were replaced by neural network prediction in the optimization process, so as to reduce the computational cost. Numerical tests indicate that the proposed method can significantly improve the computational efficiency while ensuring computational accuracy. At the same time, the proposed method has good generalization ability and can quickly converge to optimization configurations for different initial structures. This work is significant in searching for the global topology optimization design of the microstructures in acoustic-structure interaction system. 
  • Active vibration control method based on left eigenstructure assignment and frequency response function
    XIA Maolong1, YANG Hanyin1, GUO Yitong1, LIU Shuang2, LI Yongzheng1
    Journal of Vibration and Shock. 2025, 44(8): 143-150.
    Abstract ( 107 ) Download PDF ( 65 )   Knowledge map   Save
    A new active suppression method of low-frequency vibration is was proposed based on frequency response function and the left eigenstructure assignment. The method uses the The frequency response data was used to avoid the numerical error problem in modeling, and establishes the mathematical relationship between among the actuator arrangement, the left eigenvectors and the external excitation force was established. The low frequency vibration of the structure is was suppressed by velocity and displacement feedback. Based on this, a method to optimize the actuator arrangement is was proposed, which greatly reduces the number of actuators required. The simulation results show that this method can effectively suppress the vibration of the structure with only a few actuators, which shows good practicability and engineering application prospect.
  • NES-based vibration mitigation model and dynamic response analysis for underground granary
    YANG Heng1, MA Jianjun1, 2, WANG Chaosheng1, 2, HOU Chao1, CUI Li1
    Journal of Vibration and Shock. 2025, 44(8): 151-159.
    Abstract ( 158 ) Download PDF ( 40 )   Knowledge map   Save
    Underground granaries efficiently utilize subsurface space and exhibit strong resistance to external disturbances. To investigate the dynamic characteristics of the interaction between the underground granary structure and surrounding soil, this study examines the steel piles in prefabricated underground granaries were examined in this paper. Employing Nonlinear Energy Sink (NES) theory, the surrounding soil is was modeled as a nonlinear Winkler foundation, and the steel piles are were represented as simply supported Euler-Bernoulli beams. The motion equation of the beam-soil system is was formulated using Hamilton's principle, incorporating a foundation reaction coefficient to describe the soil's nonlinear stiffness. The incremental harmonic balance method is was used to derive a semi-analytical solution, which is was compared with numerical solutions. The impact of parameters like damping, mass ratio, and foundation reaction coefficient on the dynamic response under harmonic excitation is was analyzed, both with and without the NES effect. The soil field's suppression of structural vibration response under different conditions is was also assessed. The Results results demonstrate that,  with appropriate damping, mass ratio, and foundation reaction coefficients, steady-state vibration energy is reduced across a wide frequency range, significantly lowering resonance energy peaks and response amplitudes. Optimal parameters achieve a vibration energy attenuation rate of 99.39%. This study elucidates the vibration and energy dissipation effects of soil-structure interaction, providing a theoretical basis for NES-based vibration reduction design of underground granaries.
  • Numerical simulation of the water-entry, free settling and touch-bed process of multiple discrete rocks using the CFD-DEM
    CHANG Shuqi1, JI Chunning1, CAO Yonghua2, 3, 4, 5, YUE Changxi2, 3, 4, 5
    Journal of Vibration and Shock. 2025, 44(8): 160-168.
    Abstract ( 117 ) Download PDF ( 44 )   Knowledge map   Save
    Integrating the combined Finite-Discrete Element Method (FDEM) with the Computational Fluid Dynamics (CFD) software FLOW-3D, a CFD-DEM based fluid-solid coupling model was established. This model simulates the dynamic process of multiple rocks entering water, freely settling, and hitting the bottom bed. The study analyzes hHow different rock equivalent diameters, shapes, and water-entry velocities affect touch-bed velocity and force was analyzed. It was found that rocks’ settling velocity decreases rapidly upon water entry, stabilizing before dynamic equilibrium settling and collision with the bottom bed. Touch-bed velocity increases with equivalent diameter, with equant rocks having the highest velocity, followed by rod-shaped rocks, and then disk-shaped rocks. The maximum touch-bed force also increases with equivalent diameter in nonlinear relationships, from which empirical formulae for touch-bed force were derived. Significance analysis showed that the rock’s equivalent diameter has the most significant effect on touch-bed force, followed by shape, and then water-entry velocity. 
  • A study on the nonreciprocal band gap characteristics of axial tube phononic crystals based on spatiotemporal pumping
    LU Zixun, YAO Lingyun
    Journal of Vibration and Shock. 2025, 44(8): 169-174.
    Abstract ( 91 ) Download PDF ( 25 )   Knowledge map   Save
    A spiral phononic crystal structure that can generate dynamic boundaries is was designed based on the adiabatic evolution principle of nonreciprocal waveguide theory, which can solve the problem of unidirectional isolation control in shaft tube structures. The spatiotemporal pump formed by this structure is was used to achieve nonreciprocal transmission of elastic waves in the shaft tube, which can achieve unidirectional isolation of shaft vibration. This design uses =theoretical Theoretical and simulation calculations were used to analyze the energy band structure of the periodic tube. It was found that the rotation of the tube can deflect the energy band of the periodic structure, and the dynamic boundary formed by it has a unidirectional pumping function. The offset frequency range can be tuned by changing the angular velocity. The modulation rate reaches 15.89% when the modulation speed is 10 m/s. To verify the effectiveness of the unidirectional bandgap of the shaft tube, finite element simulation and experimental verification were conducted on the unidirectional isolation performance of the shaft tube. The amplitude normalization curve obtained has good matching with the nonreciprocal bandgap offset characteristics. The results indicates that modulating the propagation mode of elastic waves through mechanical device motion is a new approach to achieve unidirectional vibration isolation of shaft tube structures.
  • Numerical study on wind characteristics of ideal U-shaped canyon with different width-depth ratios
    JING Hongmiao1, 2, 3, 4, CUI Shengnan3, LI Weikang3, QIAO Mingzhe5, ZHAO Wanru3, XU Haoran3
    Journal of Vibration and Shock. 2025, 44(8): 175-183.
    Abstract ( 112 ) Download PDF ( 53 )   Knowledge map   Save
    Terrain in mountain area is variable, where the wind characteristics are more complex than those in plain area. To further understand the wind characteristics in U-shaped canyon, a series of ideal U-shaped canyons were employed to study the mean and fluctuating wind characteristics, as well as the flow field, with different width-depth ratios based on LES (Large Eddy Simulation) approach. The results indicated that the width-depth ratio had a significant influence on the wind characteristics. With the decrease of the width-depth ratio, the mean wind speed gradually decreases, the acceleration effect in the canyon weakenings, the wind attack angle at the mid-bottom of the canyon slowly changing changes from positive to negative, while the turbulence intensity increasingincreases. The power spectra are in good agreement with the von Kármán spectrum, and the peak frequency of fluctuating wind spectrum at the center of the canyon is the smallest when the width-depth ratio is 0.33. Due to the blocking effect of mountains, the airflow in front of the entrance of the canyon with a small width-depth ratio is more intense, and the vortices inside the canyon are relatively larger. The turbulence integral scales in the canyon increases first and then decreases with the increase of height, and increases over the canyon. With the increase of the width-depth ratio, variation of the turbulence integral scale decreases in the canyon is small.
    • FAULT DIAGNOSIS ANALYSIS
  • Damage identification method of offshore wind turbine support structure based on VMD and FCM clustering algorithm
    REN Yijian, DIAO Yansong, L Jianda, HOU Jingru
    Journal of Vibration and Shock. 2025, 44(8): 184-191.
    Abstract ( 113 ) Download PDF ( 39 )   Knowledge map   Save
    When using vibration response and supervised learning algorithm to identify the damage of offshore wind turbine supporting structure under operating conditions, the influence of harmonic components with high energy proportion in the response and the problem that supervised learning algorithm needs to manually define labels will be encountered. Therefore, the Variational Modal Decomposition (VMD) and Fuzzy C-Means (FCM) clustering algorithm awere employed to identify the damage of offshore wind turbine supporting structure in this paper. In order to eliminate the harmonic components in the vibration response signal,firstly, the VMD is was used to decompose the acceleration response signal, and the structural modal response (only containing the natural frequency of the structure) signal is was selected as the analysis signal. Then, the time domain, energy, energy ratio and sample entropy of the modal response signal are were calculated to construct the feature matrix, and the principal component analysis (PCA) is was used to reduce the dimension of the feature matrix to obtain the damage feature matrix. The damage feature matrix is was input into the FCM clustering algorithm, and the damage state of the structure is was obtained by clustering analysis. The model test data of damage identification of offshore wind turbine supporting structure under displacement excitation verify the effectiveness of the proposed method. ,The proposed this methodwhich is not affected by the harmonic components in the response. On the other hand, it does not need to manually define the label because the FCM clustering algorithm belongs to the unsupervised learning algorithm.
  • Fuzzy projection twin broad learning and its application to rolling bearing fault diagnosis
    ZHENG Fenglei, PAN Haiyang, ZHENG Jinde, TONG Jinyu, CHENG Jian
    Journal of Vibration and Shock. 2025, 44(8): 192-198.
    Abstract ( 105 ) Download PDF ( 30 )   Knowledge map   Save
    Vibration signals obtained from sensors often contain substantial noise and redundant information, which can significantly impact the accuracy of rolling bearing fault diagnosis. To address this challenge, this paper proposes a rolling bearing fault diagnosis method was proposed in this paper based on Fuzzy Projection Twin Broad Learning (FPTBL). In the FPTBL modeling process, a projection direction is was firstly found for each type of data in the feature space, and a fuzzy membership function is was used to calculate the membership degree. To address the sensitivity of model to noise information, the likelihood of each sample belonging to each category is was evaluated, and the projection direction is was adjusted to make similar samples closer to each other and disperse dissimilar samples. Meanwhile, FPTBL not only focuses on minimizing empirical risk, but also on minimizing structural risk. To prevent model overfitting, it constructs non-parallel projection spaces were constructed and incorporates regularization terms were incorporated into the objective function to effectively weaken the impact of redundant information on the model. Experimental validation on two rolling bearing datasets demonstrates that FPTBL achieves superior performance than existing methods in terms of accuracy, Kappa coefficient, F1-score, precision and recall rate.
  • Multi-stage denoising combined with feature-enhanced rolling bearing fault diagnosis
    LIAO Yunhu, JI Guoyi
    Journal of Vibration and Shock. 2025, 44(8): 199-208.
    Abstract ( 128 ) Download PDF ( 79 )   Knowledge map   Save
    Since it is difficult to extract the early fault features of rolling bearing in the background of strong noise, this paper proposes a new method was proposed in this  paper.which is to prePre-denoise processing was performed through multi-stage denoising that combining the improved singular value decomposition (ISVD) with the improved wavelet decomposition decomposition,called multi-stage denoising and to post-processing was performed through parameter adaptive multipoint optimal minimum entropy deconvolution adjusted (MOMEDA) .Aim at singular value decomposition denoising method is hard to select singular value, this paper proposes an improved SVD denoising method was proposed to avoid the selection of singular value firstly. Aim at the defects of soft and hard threshold wavelet denoising, a new wavelet denoising method is was proposed secondly. In view of the problem of multi-point kurtosis spectrum (Mkurt) is sensitive to noise in solving the cycle, this paper uses multi-stage denoising was used to pre-process the signal, and then uses the new cycle index multi-point envelope kurtosis spectrum (Mekurt) was used to identify the cycle finally. The effectiveness and superiority of the present proposed method is was verified by simulation and experiment.
    • EARTHQUAKE SCIENCE AND STRUCTURE SEISMIC RESILIENCE
  • Experimental study on seismic performance of assembled steel fully recycled concrete frame structure
    CHEN Yuliang1, 2, 3, WANG Shuangyi1, LIU Jie1, JIANG Rui1, YE Peihuan1, 2
    Journal of Vibration and Shock. 2025, 44(8): 209-219.
    Abstract ( 127 ) Download PDF ( 33 )   Knowledge map   Save
    In order to study the seismic performance of the assembled steel fully recycled concrete frame-recycled concrete infilled wall structure, a cast-in-place steel reinforced concrete frame (control group) and two assembled steel reinforced recycled concrete frames with a scale ratio of 1:2.5 were designed. The mechanical properties such as hysteresis curve, skeleton curve, stiffness degradation, energy dissipation capacity, strength degradation and inter-story displacement angle of assembled steel reinforced fully recycled concrete were investigated by low cyclic loading test. The results show that the failure modes of the assembled steel fully recycled concrete frame and the cast-in-place ordinary concrete frame are similar, both of which are manifested as the failure of the plastic hinge zone at the beam end and the column bottom. The stiffness degradation of prefabricated steel reinforced recycled concrete frame is more obvious than that of cast-in-place ordinary concrete frame, and the maximum reduction is about 62.54 %. The energy dissipation capacity of the prefabricated steel reinforced recycled concrete frame with infill wall is the best, which is about 22.22 % higher than that of the cast-in-place steel reinforced concrete frame. The strength degradation coefficient of cast-in-place ordinary steel reinforced concrete frame and assembled steel reinforced recycled concrete frame is between 0.89 and 0.91, and the strength degradation coefficient of assembled steel reinforced recycled concrete frame with infilled wall is between 0.77 and 0.82. The displacement ductility coefficient of the assembled steel reinforced recycled concrete frame is about 2.14 ~ 4.63, which is about 118.40 % higher than that of the cast-in-place ordinary concrete structure. The ultimate inter-story displacement angle of cast-in-place steel ordinary concrete frame and assembled steel recycled concrete frame is between 1/39 and 1/28. The strain test results show that the bearing capacity of the structure is mainly controlled by the normal stress on the section. The plastic hinge begins to form at the beam end, and finally forms at the bottom of the column. The failure belongs to the beam hinge mechanism, which meets the seismic requirements of strong column and weak beam.
  • Study on seismic behavior of prestressed concrete composite shear wall
    LI Shurong1, 2, GUO Zhiyuan1, ZHANG Xin1, 2, ZHOU Guangqiang1, 2, WANG Heng3
    Journal of Vibration and Shock. 2025, 44(8): 220-227.
    Abstract ( 110 ) Download PDF ( 36 )   Knowledge map   Save
    A new type of prestressed reinforced concrete composite shear wall was proposed in this study. Due to arrangingthe prestressed steel in the precast slab, the thickness of the concrete precast slab was reduced, and the transportation and lifting efficiency was were correspondingly improved. The cyclic loading tests for cast-in-situ shear wall and composite shear wall with a shear span ratio of 1.5 were conducted. The failure mode, bearing capacity, ductility and energy dissipation were compared. The test results indicated that the composited shear wall exhibited exhibites the same seismic performance as the cast-in-place shear wall. Finite element models considered considering the axial compression ratio, shear span ratio and initial prestress level were established by using software ABAQUS. The accuracy of the model was validated by comparing simulated results with experimental results. The analysis results showed that under a high axial compression ratio or a low shear span ratio, the bearing capacity and ductility of the new composite shear wall were are higher than those of the cast-in-place shear wall. With the increase of the initial prestress level, the bearing capacity increased increases and the failure mode changed changes from shear failure to beading failure. Owing to the horizontal prestressed bars in the composite wall, the development of diagonal cracks in the composite shear wall was is delayed and the shear capacity improved. The initial prestress value of 0.50fptk is suggested.
  • Analysis of the current research status on the dynamic performance and seismic performance of masonry pagodas
    LU Junlong, LI Mingdong, WU Xiaoqin, WANG Zhenshan, LI Xiaolei, TIAN Jianbo
    Journal of Vibration and Shock. 2025, 44(8): 228-240.
    Abstract ( 128 ) Download PDF ( )   Knowledge map   Save
    Masonry pagodas are important cultural heritage buildings,with a relatively large number of existing examples and distinguished by their unique structural forms and the relatively large number of existing examples. Due to their high aspect ratios and relatively low shear strength, these pagodas exhibit notable dynamic responses under seismic actions, making them highly susceptible to damage. This study examines the The structural features of these pagodas were examined in this study, summarizing the patterns of seismic damage in various structural forms were summarized. It compiles and analyzes The formulas for calculating the natural vibration periods of these structures were compiled and analyzed and compares the results of in-situ dynamic tests were compared. Focusing on key issues related to damage identification, dynamic response, damage mechanisms, and vibration control, the analysis highlights highlighted the fundamental patterns of seismic response in masonry ancient pagodas and the mechanical mechanisms of seismic damage formation and control. By integrating research on damage identification, this study also analyzes the basic characteristics of dynamic responses were also analyzed obtained from shaking table tests and numerical analyses, and summarizing the variations in seismic responses of the pagodas were summarized. Analyzing the damage modes of masonry ancient pagodas under seismic actions, this study examines the seismic damage mechanisms of the pagodas, organizes existing reliability assessment methods, clarifies the influence of foundation soil on the seismic response of the pagoda structure, and identifies key issues in the restoration and seismic control of ancient pagodas. Based on the failure mode of masonry pagodas under seismic action, the seismic failure mechanism of the pagodas was analyzed, the existing reliability evaluation methods were sorted out, the influence of foundation soil on the seismic response of the pagoda structure was clarified, and the key issues of restoration and seismic reduction control of thepagodas were identified. This work provides valuable insights for the seismic research and performance enhancement of masonry ancient pagodas.
  • Study on seismic effect of Shenjiabao slope site in Beichuan
    LI Xiaobo1, 2, WANG Tianhu1, 2, WANG Huaiqiang1, 2, LIU Yaokuo1, 2, XI Shuheng1, 2, ZHAO Yang1, 2
    Journal of Vibration and Shock. 2025, 44(8): 240-250.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on the microtremor data of Shenjiabao slope site in Beichuan, this paper uses the horizontal-to-vertical spectral ratio method (HVSR method) was used to explore the seismic effect characteristics of slope site. The results show that: (1) The HVSR curve of Shenjiabao slope site is mainly bimodal or multimodal. The peak frequency of the stratum is concentrated in 1.39 Hz ~ 3.90 Hz, and the amplification coefficient corresponding to the peak frequency is between 1.89 and 3.80, showing a relativelymore obvious local topographic amplification effect. (2) The dominant directions of microtremors at the top and waist of Shenjiabao slope are easy to distinguish, which are 30° ~ 80° and 110° ~ 160° respectively. When the peak frequency of multiple measuring points in a certain area tends to be consistent, the directional distribution is also more concentrated, which reveals the control effect of the underlying stratum structure change on the directional characteristics of the site soil layer. (3) The dominant direction of the joint occurrence of the Shenjiabao slope is 60° ~ 80°, which is in good agreement with the dominant direction of the ground pulsation at the top of the slope (30° ~ 80°), but it intersects with the slope strike (110°) at an acute angle. Compared with the seismic effect characteristics of the Wangjiayan landslide site, the layout of the anti-slide pile at the front edge of the Shenjiabao slope is an important factor in blocking the formation of the landslide. The research results provide a reference for exploring the seismic effect of slope sites and the prevention and control of slope disasters.
  • Experimental study on seismic performance of masonry wall strengthened with sprayed ECC
    LI Xiaoqin1, LI Keran1, ZHANG Tian2, XU Wei1, LIANG Limin3
    Journal of Vibration and Shock. 2025, 44(8): 251-258.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Engineered Cementitious Composites (ECC) are widely used in structural strengthening due to the characteristics of strain hardening and multiple cracking. However, existing research on ECC strengthening was is mainly manually applied, which is with low retrofitting efficiency. For strengthening a large number of rural masonry structures, the sprayed ECC retrofitting method was investigated. Pseudo-static tests were conducted on four un-strengthened and strengthened masonry walls, which were with,of traditionally manually applied and the new sprayed ECC. The results indicated that the strengthening efficiency of sprayed ECC is 5.27 times that of the manual application. The ECC strengthening layers were are with good adhesion performance to the wall surface, providing effective strengthening effects and improving the non-ductile failure characteristics of the masonry walls. Meanwhile, the strengthening effect of sprayed ECC is comparable to that of manual plastering, where the sprayed ECC strengtheningwhich can effectively enhance the masonry wall’s bearing, deformation and energy dissipation capacities and enhancing enhance the comprehensive seismic performance of the masonry walls.
    • CIVIL ENGINEERING
  • Buffeting and cable fatigue of cable-stayed bridges with Π-shaped section considering effect of crossbeams
    FANG Zhao1, YANG Fan2, LI Aiqun2, 3, CAO Baoya3
    Journal of Vibration and Shock. 2025, 44(8): 259-266.
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    The crossbeams may affect the three static wind force coefficients of a cable-stayed bridge with a П-shaped main beam section, and further affect the wind-induced buffeting and fatigue analysis results of cables. In this paper, a certain single-tower cable-stayed bridge with a П-shaped main beam section iwas taken as an example and a segmentation-based 2D simulation method for the consideration of main beams is was proposed. Based on computational fluid dynamics (CFD) simulation, the three static wind force coefficients of the bridge deck are were obtained by segmentation-based 2D simulation method and 3D simulation method. The indexes such as bridge deck buffeting effect, cable fatigue damage and corresponding error rates of the above two simulation methods and the method without the consideration of the crossbeam effect are were compared by finite element analysis. The effect of crossbeam spacing, wind speed, wind attack angle and terrain roughness on the above indexes are were discussed and the feasibility of the segmentation-based 2D simulation method is was analyzed. The results show that the ignorance of the crossbeam effect will lead to large error in bridge deck buffeting and cable fatigue analysis results of the cable-stayed bridge with П-shaped section; The proposed segmentation-based 2D simulation method is not suitable for cable fatigue analysis, but its buffeting analysis accuracy increases with the increase of beam spacing, the increase of terrain roughness, the decrease of the wind speed and the decrease of the absolute value of the wind attack angle, and can be well applied to the buffeting analysis of urban cable-stayed bridges in areas with a small reference wind speed. The bridge deck buffeting lateral displacement and the cable fatigue damage of the cable-stayed bridge increase with the increase of the wind speed, the absolute value of the wind attack angle and the terrain roughness roughness.As the beam spacing increases, the buffeting lateral displacement increases while the cable fatigue damage decreases. while they increase and decrease with the increase of the beam spacing, respectively. 
  • Identification of vibration displacement and dynamic characteristics of piers based on the kernelized correlation filters algorithm
    CHEN Liangyu1, CAI Wei1, XIE Wen1, HE Tiantao2, 3
    Journal of Vibration and Shock. 2025, 44(8): 267-275.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Evaluating the mechanical performance and operational conditions of bridge structures relies on accurately measuringement of vibration displacement. Such measurement can provide essential parameters, such as mode and frequency, to assess the operational status and condition of damaged bridge structures. However, traditional displacement monitoring techniques have high cost, low accuracyare expensive, have low accuracy, and offer and limited measurement positions. This paper proposes a A low-cost, non-contact, and multi-point measurement method was proposed in this  paper,based on the Kernelized correlation filters (KCF) algorithm to measure the vibration displacement of bridges. The proposed method used shaking Shaking table tests on a dual-column pier model were conducted  ,with energy dissipation links under different white noise sweeps. The recorded vibration displacement from a laser displacement sensor (LDS) was used as a reference for comparison. The natural frequencies and mode shapes of the dual-column pier and bridges were identified using the covariance-driven stochastic subspace identification method. The study verified the The reliability, feasibility, and accuracy of machine vision technology in identifying the natural frequencies and mode shapes of bridges were verified. The results showed that the small amplitude vibration displacement of the dual-column pier identified by the KCF algorithm is almost consistent with the waveforms, change trends, and peak values recorded by LDS, with a maximum peak error of 4%. The error between the natural frequencies identified by the KCF algorithm and the LDS results was within 2.5%. The confidence level of the mode shapes identified between both approaches was above 0.90.
  • Numerical simulation study of self-anchored suspension bridge coated with polyurea concrete under the effect of near-field explosion
    ZHOU Guangpan1, CHEN Yipeng1, WANG Rong2, DING Jianguo2, DONG Jianjun1
    Journal of Vibration and Shock. 2025, 44(8): 276-286.
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    To study the protective effect of polyurea coating on the weakest position of the super-wide concrete self-anchored suspension bridge under the near-field blast loading, a real super-wide concrete self-anchored suspension bridge was selected as the background, and the numerical simulation was used to analyze the damage characteristics and dynamic response of the bridge under the blast loading. The finite element model of the whole bridge was established by using SOLIDWORKS and HYPERMESH, and the dynamic response of the bridge under different explosive equivalents and different lateral and longitudinal blast positions and different polyurea thicknesses was analyzed parametrically by LS-DYNA, and the damage characteristics of the whole bridge and the vertical displacement of the bottom plate before and after the coating of polyurea under the blast loading were compared. The results show that polyurea coating can effectively improve the blast resistance of concrete self-anchored suspension bridges. For different explosion positions in the lateral and longitudinal directions, the weakest positions are the middle box girder and 1/2 span, respectively. For different polyurea thicknesses, tand the optimal polyurea thicknesses for the weakest positions in the lateral and longitudinal directions are 8mm and 15mm, respectively. The research results can provide important references for the wartime reinforcement and protection of super-wide concrete self-anchored suspension bridges.
  • Numerical study on the characteristics of fluctuating wind pressure for a new type of near-rail sound barrier on viaducts
    HU Rui1, 2, BAO Yulong3, 4, LI Yongle1, 2, WU Mingrui1, 2, TAN Qiu4
    Journal of Vibration and Shock. 2025, 44(8): 287-296.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    As a new type of sound barrier structure, the central near-rail sound barrier is close to the track and is susceptible to the influence of strong perturbing airflows, which may lead to structural vibrations,  damage,  or fatigue failure more easily. Taking the near-rail sound barrier on a certain urban railway viaduct as the engineering background, a CFD numerical analysis model of the D-type train passing through the sound barrier-bridge system was established. On the basis of verifying the independence of the numerical model, the distribution characteristics of fluctuating wind pressure in the vertical and longitudinal directions of the sound barrier were investigated. The influence of parameters such as train speed, the distance between the train center and the sound barrier, and the height of the sound barrier on the fluctuating wind pressure was analyzed. A prediction formula for the peak fluctuating wind pressure of the sound barrier containing multiple parameter variables was provided. The results indicate that the sound barrier is primarily affected by the leading and trailing wave effects of the train. The negative pressure peak value of the leading wave is the largest in the wind pressure time history curve. As the measurement point height increases, the absolute value of the negative pressure peak of the sound barrier's leading wave gradually increases. Different parameters have a significant impact on the peak value of fluctuating wind pressure. This peak is found to be quadratically related to train velocity, inversely proportional to the square of the distance parameter, and proportional to the barrier’s height to the 1.1 powerthe 1.1 power of the barrier's height. The prediction of the peak fluctuating wind pressure when multiple parameters are altered shows a high degree of fit between the predicted values and the simulated values, indicating that the prediction formula has reliable accuracy and can provide reference for the design of new types of central near-rail sound barriers.
  • Research on bridge ship collision alarms using natural excitation technique to extract the free decay vibration signals
    SU Binjian1, ZHANG Xin1, WEI Bin1, XU Zhaofeng1, 2, ZHANG Jian2
    Journal of Vibration and Shock. 2025, 44(8): 297-308.
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    Traditional methods using vibration threshold algorithms and vibration time-domain feature vector algorithms face difficulties in identifying ship collision signals from the measured vibration acceleration data of bridges under ship impact conditions. To address the problems encountered in bridge ship collision anomaly alarms using measured acceleration data, including different threshold settings, difficulties in signal type recognition, and identification results susceptibility to environmental noise, this study proposes a method for bridge ship collision alarms was proposed in this study,using natural excitation technique to extract the acceleration free vibration decay response signal. Firstly, a sliding window algorithm is was used to extract corresponding acceleration subsequences from the measured data. Then, the natural excitation technique is was applied to extract the vibration response curve from the acceleration subsequences, and the Hilbert transform is was used to extract the envelope of the vibration response signal. The attenuation function is was applied to determine the signal type based on the envelope. On this basisBased on this, the Mahalanobis distance mean ratio is was calculated for different states. The Chauvenet method is was used to judge the abnormal values of the Mahalanobis distance mean ratio of the acceleration vibration response at different bridge pier tops. The occurrence time and magnitude of the abnormal values are were used to determine the timing of the ship collision. Finally, using taking the measured acceleration data from two ship-bridge collision events on the Jiujiang Bridge as an example, the acceleration vibration decay signals at different pier top positions and the Mahalanobis distance mean ratio under different states are were analyzed. The results demonstrate that the proposed method is capable of identifying the timing of ship collisions and can effectively perform ship collision alarms, overcoming the limitations of traditional vibration time-domain feature vector algorithms in recognition. Moreover, the algorithm utilizes the characteristics of impact vibration decay and solves the problem of signal type recognition difficulty in general bridge ship collision algorithms.
  • Study on the randomness of vibration sources on ordinary track bed in the underground section of a subway line
    WANG Youhan1, LIAO Yingying1, ZHANG Peijie2, ZHANG Hougui3
    Journal of Vibration and Shock. 2025, 44(8): 309-314.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    For a long time, wWhen conducting environmental impact assessments on environmental vibration caused by urban rail transit, the chain formula of HJ453 is often used for preliminary prediction in current research. Among them, t，and the selection of vibration source strength will have a decisive impact on the final prediction results and control measures. In order to reveal the selection principle of vibration source strengths of ordinary monolithic track beds as a reference, this paper selects four field test datas were selected in this paper,with similar test conditions on a certain Beijing subway line for statistical analysis. The research results show that after statistical hypothesis testing, the vibration source strength still satisfies the normal distribution characteristics, which shows that it is reasonable to use statistical data with a certain confidence coefficient to characterize the vibration source strength; Even under similar conditions such as line conditions, driving speed, tunnel depth, and vehicle operating conditions, the vibration source strengths of different ordinary monolithic track beds still show great differences, which it indicates that the vibration source data of small samples obtained by engineering analogy method cannot be used as the only reference basis for environmental impact assessment prediction; for example, using the average value of current standards for prediction, traditional method useing of the vibration source strength of 80 dB as the reference value for ordinary monolithic track beds can obtain conservative results.
  • Study on aerodynamic force characteristics and flow field mechanism of wide-width double-box composite beams with different aspect ratios
    ZHANG Xiao1, ZHAO Renyan2, ZHANG Dewang2, LIU Xiaobing2, 3, LI Huijun4
    Journal of Vibration and Shock. 2025, 44(8): 315-324.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on a domestic wide-width double-box composite beam bridge, the aerodynamic characteristics and flow field mechanisms of wide-width double-box composite beams with different aspect ratios were investigated investigated,using a combined approach of wind tunnel test and numerical simulation in this study. Firstly, a total of eleven wind attack angles ranging from -10° to 10° with an interval of 2° were selected for the investigation under an aspect ratio of the actual bridge of 12.8. Subsequently, focusing on the 0° wind attack angle (horizontal flow direction), six different aspect ratios (9, 11, 12.8, 15, 17, and 19) were chosen for analysis, based on the range observed in practical engineering applications for double-box composite beams. The results indicate that,  under the aspect ratio of the actual bridge, as the wind attack angle varies from -10° to 10°, the drag coefficient of the double-box composite beam initially first decreases and then increases; the direction of lift force changes from downward to upward, with the absolute value of the lift coefficient initially first decreasing and then increasing; the direction of torque changes from counterclockwise to clockwise, and the clockwise torque coefficient initially first increases and then decreases. At a wind attack angle of 0°, as the aspect ratio of the composite beam increases, the drag coefficient remains constant initially first and then increases; the direction of lift force changes from downward to upward, with the absolute value of the lift coefficient initially first decreasing and then increasing; and the torque coefficient gradually decreases. For the wide-width double-box composite beams with different aspect ratios under 0° wind attack angle, a calculation formula for the three-component force coefficient is was presented, which can provide a reference for the wind load design of wide-width double-box composite beams in practical engineering.
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