28 March 2025, Volume 44 Issue 6
    

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    VIBRATION THEORY AND INTERDISCIPLINARY RESEARCH
  • LI Sheng1, ZHAO Yuhao2, DU Jingtao3, CUI Haijian4
    Journal of Vibration and Shock. 2025, 44(6): 1-12.
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    As one of the basic engineering units, elastic beam systems are widely used in various fields, including architecture, aerospace, ocean engineering, and others.It is of great engineering significance to control the vibration level of elastic beam systems.To reveal the potential application of double-coupling nonlinear oscillators in the vibration control of double-beam systems, a dynamic behavior prediction model of double-beam systems with double-coupling nonlinear oscillators was established, where the Lagrange method was used to predict the dynamic behavior of the double-beam system.On the basis of ensuring the correctness of the numerical results, the typical operating mode of the double-coupling nonlinear oscillator was studied, and the influence of the double-coupling nonlinear oscillator parameters on the dynamic behavior of the double-beam system was discussed.The results show that the introduction of the double-coupling nonlinear oscillators can effectively realize the synchronous vibration control of each substructure of the double-beam system.On the one hand, when the double-coupling nonlinear oscillator is in the multi-frequency linear/nonlinear vibration control mode, the vibration of each sub-beam in the main resonance region of the double-beam system is effectively suppressed.Additionally, the multi-frequency nonlinear vibration control mode excites the complicated vibration responses of the double-beam system, resulting in the unidirectional transmission of vibration energy in time domain between elastic beams and double-coupling nonlinear oscillators.On the other hand, according to the vibration control requirements, the working mode and vibration control effect of double-coupling nonlinear oscillators can be realized by adjusting its core control parameters.Setting appropriate core control parameters for double-coupling nonlinear oscillators is conducive to enhancing the vibration control effect of the double-coupling nonlinear oscillators on the main resonance region of the double-beam system.
  • JI Yongjian1, 2, 3, HAN Qichao3, XU Xiaokang3
    Journal of Vibration and Shock. 2025, 44(6): 13-27.
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    Due to the low stiffness of serial industrial robots, the robotic milling process is prone to chatter due to the improper selection of processing parameters or robot pose, which will reduce the surface quality of the workpiece and damage the robot equipment.In order to predict the chatter stability of robotic milling, the variation of robot end stiffness along with the spatial pose was studied by constructing the stiffness model of the robot.The dynamic model of the spindle system was constructed, then the influence of the speed effect on the dynamic characteristics of the tool tip was studied, and the mapping function between the spindle speed and the natural frequency of the tool tip was constructed by data fitting method.A robotic milling dynamic model considering the coupling effects between the robot and spindle system was proposed.The damping ratio and modal mass at the tool tip of the robotic milling system were obtained by hammer experiments, and the stability lobe diagram of the robotic milling system considering different factors was obtained.The variation law of milling chatter stability under the coupling effects of the robot-spindle system was revealed and verified by experiments.The results show that the stability lobe diagram obtained when considering the robot-spindle system coupling effects is more consistent with the actual milling state, which can effectively improve the prediction accuracy of robotic milling chatter stability.
  • GAO Fan1, REN Yaning1, LI Junkuo1, ZHOU Wanzhi2, ZHANG Dachang2
    Journal of Vibration and Shock. 2025, 44(6): 28-37.
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    Transmission lines are subjected to dynamic loads such as wind loads, conductor vibrations, and dancing for a long time, resulting in loss of bolt preload or even loosening, which seriously affects the safety of transmission towers and lines.The joints of the tower are usually connected by bolts, which bear the shear force and lateral vibration load.However, relevant codes only specify that the tightening torque of bolts should achieve the purpose of tightening and preventing loosening, and other factors that affect the anti-loosening characteristics are often ignored, which may affect the long-term tightening state and daily operation and maintenance of bolts.Transverse vibration tests were conducted on 6.8 grade M16 rough high-strength bolts commonly used in transmission towers, and the effects of different frequencies, amplitudes, and torques on the bolt preload and fastening characteristics were studied.Then, a simulation analysis of the anti-loosening characteristics of bolts under transverse vibration load was carried out, and the results were compared and verified with the test results and specifications.The bolt deformation and thread area stress under transverse vibration state, as well as the bolt loosening law under different initial preloads were investigated.The results show that the decline curve of preload can be divided into two stages: rapid decrease and steady decrease.When the transverse vibration frequency is lower, the amplitude is larger, and the torque is smaller, the bolt is more likely to loosen.Under transverse vibration load, the stress distribution in the threaded area is uneven, with an overall trapezoidal distribution.Furthermore, the stress distribution of the thread gradually decreases from the screw section towards the free end, and the maximum stress point moves from the middle position to both sides.The higher the preload, the better the anti-loosening performance.Therefore, it can be seen that the preload force corresponding to the torque method specified in the code is relatively low.It is recommended to use preload force control and take 0.5 to 0.6 times the yield tightening axial force.
  • ZHU Rui1, 2, WANG Xinrou1, HAN Qingpeng1, WANG Xuechao1, JIANG Tianzhen1
    Journal of Vibration and Shock. 2025, 44(6): 38-46.
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    The influence of electromagnetic coupling excitation may affect the normal performance of the rotor system of gas turbine generator set. In order to study the coupling fault of air gap eccentricity and rubbing, it is necessary to quantitatively analyze the influence of rotational speed, excitation current and compound eccentric parameters on the dynamic response of the system. In this paper, by analyzing the change of air gap magnetic field energy in the case of air gap compound eccentricity, the analytical expressions of unbalanced magnetic pulling force and rubbing force caused by compound eccentricity are established. On this basis, the dynamic equations of double-span rotor with unbalanced magnetic pulling force fault and rub-impact fault are established and solved numerically by Runge-Kutta method. The results show that the influence of unbalanced magnetic pull on the dynamic response of the system increases obviously with the increase of rotational speed. The eccentricity of composite air gap leads to the increase of multiple frequency doubling components. The research results of this paper can provide a theoretical basis for the fault diagnosis of rotor system.
  • YANG Zijian1, WANG Jun1, 2, ZHANG Jianchao2, WEN Shaofang2
    Journal of Vibration and Shock. 2025, 44(6): 47-57.
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    Nonlinear energy sink (NES) systems primarily dissipate energy through damping elements, and altering the location of the damping components significantly influences the performance of the systems. In this study, a novel piecewise stiffness NES with grounded damping is proposed, and the dynamic characteristics of the system are systematically investigated. Firstly, based on the complexification-averaging method and the method of multiple scales, the slow-flow equations of the system under 1:1 resonance are derived. Secondly, the effects of different parameters on the system's slow invariant manifold were analyzed. Subsequently, the occurrence of strongly modulated response (SMR) was determined by analyzing the topology of the slow invariant manifold. Finally, the effects of different positions of the grounded damping on the vibration suppression performance of the system under various pulse and harmonic excitations were studied, and comparisons were made with the case of no grounded damping. Additionally, the system parameters are optimized by the nutcracker optimization algorithm. The results indicate that introducing grounded damping into the piecewise stiffness NES can effectively improve the system's vibration suppression performance. The damper attached to the primary system and grounded is suitable for cases requiring high vibration reduction but lower demands on dissipation time, while the damper attached to the additional mass and grounded is suitable for scenarios where rapid dissipation of the primary system's energy to a lower level is required.
  • XIANG Zijian1, DU Weiqi1, QIU Xiaobiao2, CHEN Shilei3
    Journal of Vibration and Shock. 2025, 44(6): 58-65.
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    The acoustic black hole (ABH) effect has been shown to be a potential method for vibration control and energy harvesting. However, it faces structural strength problems due to its small localized thickness. In this paper, for the acoustic black hole plate structure, an analytical model for vibration fatigue life prediction of acoustic black hole plate under random excitation is developed by using analytical method. Based on the assumed vibration mode method, the stress frequency response function of the acoustic black hole plate is derived, and the random vibration displacement power spectral density function of the structure is obtained based on the consideration of random excitation. The P-S-N curve of the material AL6061 was also estimated based on the genetic algorithm. In addition, the correctness of the model and its prediction results were verified by using COMSOL and MATLAB software, and it was found that the intrinsic frequency deviation of the two was only 0.11%, and the accuracy of the displacement PSD was in good agreement. The fatigue life analysis shows that the smaller the truncated thickness h_0 and the larger the black hole radius〖 r〗_abh, the better the ABH effect but also the smaller the life.
  • WU Shiliang1, LIU Penghui2, 3, YANG Yiqian2, 3, DONG Zhensheng2, 3
    Journal of Vibration and Shock. 2025, 44(6): 66-73.
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    Field tests on track vibrations in a subway tunnel, indoor vibrations, and secondary structure noise in nearby buildings were conducted. Vibrations and noise levels before and after speed reduction were evaluated and com-pared. The results show that tunnel vibrations, indoor vibrations, and secondary structure noise varied significantly be-tween trains, displaying notable dispersion. After speed reduction, overall vibrations decreased, but dispersion increased, significantly influenced by train conditions. Vibrations in the 40-80Hz frequency range are the main sources of indoor vibrations and secondary structure noise. Post-speed reduction, indoor vibrations and secondary structure noise levels decreased overall, but the impact duration extended, potentially increasing the total exposure to vibration and noise. Speed reduction is less effective for trains with poor wheel conditions. Wheel re-profiling is recommended to improve wheel-rail interaction and reduce vibrations and secondary structure noise. Time-segmented speed limits and wheel-rail improvements can inform enhancements in subway vibration and noise control.
  • SHOCK AND EXPLOSION
  • XU Kaixuan1, 2, LI Enqi3, ZHOU Shiming1, 2, LI Daokui1, 2
    Journal of Vibration and Shock. 2025, 44(6): 74-81.
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    Chiral lattice structures offer advantages such as lightweight, high specific stiffness, and high specific strength, along with enhanced impact resistance. This research introduces a chiral Kelvin designed by leveraging the deformation mechanism of rotational rod chiral structure. Impact experiments are conducted to analyze the effect of chirality on impact resistance, revealing the underlying principles of the performance enhancement. The study examined how topological parameters influence the impact resistance. Results show that chirality significantly boosts peak impact stress and plateau stress, while marginally decreasing strain energy. The chiral Kelvin  improves impact resistance by reducing stiffness and enhancing overall deformability. The central diameter is the primary factor of the impact resistance, with moderate values of the central diameter and the angle of the connecting rods being optimal for the best impact resistance in chiral Kelvin. The study broadens the design scope of 3D chiral lattice structures and provides references for parametric design, mechanical analysis, and impact-resistant applications of chiral Kelvin.
  • LI Fan, LI Hongshuang
    Journal of Vibration and Shock. 2025, 44(6): 82-89.
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    The ground impact test is an indispensable stage before aerospace equipments are put in service so that shock wave generator is one of the most important tool for the reappearance of impact loading. In order to solve the issues of low repetition accuracy and poor controllability of shock wave, a method for optimal parameter design of porous-type shock waveform generator is proposed. According to the flow characteristics of the damping hole and the stress state of the piston, the shock response calculation model of the test system is established, as well as its discrete calculation formulation. Taking into account that the subset simulation optimization algorithm has the advantage of fast convergence and avoiding getting trapped in a local optimal solution when facing high-dimensional complex optimization problems, the algorithm is used to seek the optimal discrete combinations of the number of damping holes in each row and compared with the genetic algorithm.The results show that, with different requirements, the optimized acceleration waveform curves meet the tolerance specified in the corresponding standard, which are better than those obtained from genetic algorithm.
  • WANG Xu1, 2, QU Ke1, 2, 3, YANG Yuanping1, 3, WANG Chao1
    Journal of Vibration and Shock. 2025, 44(6): 90-103.
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    Based on the open source programs OpenFOAM and wave2Foam, we construct a high-precision numerical flume to solve the Reynolds-averaged Navier-Stokes equations. First, a high-precision tidal bore numerical flume is carried out to calculate the tidal bore, propagation, evolution, and the ability to interact with pile and column bodies. Then, we numerically calculate the change rules of surge propagation, evolution, and structural dynamic response characteristics of the pile column during the interaction between the tidal bore, and the pile column, and elucidate the complex hydrodynamic characteristics of the tidal bore, when it interacts with the pile column in different forms. Systematically analyze the influence of different tidal bore, heights, pre-tidal water depths, inclined angle and direction of the pile body on the hydrodynamic load and maximum impact pressure of the tidal bore,. Finally, based on the systematic collation of the maximum hydrodynamic load and maximum impact pressure, combined with the theoretical characterization, the theoretical calculation formulas of the maximum hydrodynamic load and maximum impact pressure are proposed to be suitable for the tidal bore, impacting on the pile columns in different forms.
  • HUANG Yonghui1, ZHAN Yufei1, ZHANG Hongbo1, LI Qinglin2, RUAN Xun3
    Journal of Vibration and Shock. 2025, 44(6): 104-112.
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    In the process of deep tunnel excavation, where extremely high in-situ stress is present, a numerical simulation method based on ANSYS/LS-DYNA software was used to study the effect of in-situ stress on surrounding rock damage caused by smooth blasting. A 3D simulation was conducted using the Structured Mesh-Finite Element-Particle Flow Coupling Algorithm (S-FEM-SPH). The study investigates the damage patterns of surrounding rock under bi-directional equivalent in-situ stress conditions ranging from 0 MPa to 40 MPa. The results indicate that the damage to the surrounding rock at the sidewalls and roof can be categorized into two phases based on the change in the distance from the blast center: a horizontal linear phase and a descending phase characterized by an inverse "S" curve. In the descending phase of the inverse "S" curve, the surrounding rock at the middle distance from the blast center shows a greater rate of damage reduction as the distance decreases. In-situ stress affects the damage to the surrounding rock at both the sidewalls and the roof, with the impact on the sidewalls being more significant than that on the roof, especially when the in-situ stress exceeds 20 MPa. By comparing the changes in effective plastic strain and the depth of surrounding rock damage at the sidewalls and roof with varying in-situ stress, the study confirms the validity of the finding that the depth of surrounding rock damage decreases initially and then increases with the rise in in-situ stress.

  • WANG Weizhan1, JING Tong2, LI Hongli3, MENG Fangao4, ZHENG Canjie4, ZHAO Taiyong1
    Journal of Vibration and Shock. 2025, 44(6): 113-120.
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    The study of kinetic energy projectiles' impact response characteristics against typical protective target plates has guiding significance for improving projectile power design. This article, through ballistic impact experiments, investigates the impact response characteristics of a 12.7mm kinetic energy projectile against three typical target plates: concrete (condition 1), armor steel (condition 2), and ceramic composite armor (condition 3). It establishes a calculation model for the fracture characteristics of brittle kinetic energy projectiles. The study finds that the tensile and shear waves generated by the impact load on the target plate are key factors influencing the change in fracture mode of the projectile core.When the impact load is relatively small, the projectile core initially exhibits elastic response characteristics (condition 1). As the impact load increases, the core shifts from tensile fracture to shear fracture, with the fracture surface transitioning from cleavage/dimple fracture (condition 2) to a predominantly cleavage fracture (condition 3). Additionally, the residual height of the projectile core gradually decreases. The theoretical model's calculated results for the kinetic energy projectile's fracture characteristics align well with the experimental results, demonstrating good applicability.
  • ZHANG Xuemei1, 2, XIE Xingbo1, ZHONG Mingshou1, GU Wenbin1, SHEN Chaohu3
    Journal of Vibration and Shock. 2025, 44(6): 121-129.
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     In order to improve the accuracy of shaped charge warhead striking underwater targets from air, a phased progressive numerical calculation model for the whole process of rod jet forming from air to underwater penetration of jet into target plate was established. The calculation model was verified by static penetration test, which improved the accuracy of the calculation model, and the error was within 5 %. In the experiment, the velocity of the shaped charge jet before entering the water, after entering the water and before the target is measured by using the on-off velocity measurement network target. The minimum error rate is 0.39 % and the average error rate is 4.16 %. Through the study, it is found that the velocity of the rod jet before and after entering the water decreases linearly, and the velocity before the target increases linearly. The penetration depth of rod jet in water increases first and then decreases with the increase of air explosion height. The optimum explosion height of shaped charge in water is 4.89 times the charge diameter, and the maximum penetration depth in water is 1.3 times the charge diameter. It provides a basis and reference for the research of shaped charge warhead in the air to isolate water and hit underwater targets.
  • WANG Yaoyao1, LUO Zhuhui1, WANG Han1, ZHOU Xisheng2, WANG Hu2, CHEN Shilu1
    Journal of Vibration and Shock. 2025, 44(6): 130-136.
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    Due to the long lead time and high cost for the preparation of rubber isolator prototypes and impact performance testing, simulation analysis is needed to evaluate the feasibility of the design or selection of structure and material before the preparation of prototypes. Referring to the drop impact test method of isolator, a finite element model for impact performance simulation analysis of vibration isolators is established in LS-DYNA, and the Mooney-Rivlin-Maxwell model is chosen as the rubber visco-hyperelastic constitutive model. In order to obtain the parameters of the constitutive model of the rubber material under the impact condition, the rubber material used in the isolator is made into a sphere, and the impact test and finite element simulation analysis of the rubber sphere and steel plate are carried out. A generalized regression neural network (GRNN) is established, and the optimized GRNN model and test data are used to predict the parameters of the constitutive model of rubber material. Carry out the impact simulation and analysis of rubber isolator, the simulation is close to the test results, and the established finite element simulation and analysis model can be used to evaluate the impact performance of the isolator, which provides a reference method to carry out the simulation and analysis of the impact performance of rubber isolators and the acquisition of the parameters of the constitutive model of rubber material under the impact condition.
  • LU Lin1, 2, YANG Pengjie1, LIU Lanyang3, ZOU Rui3, CHEN Kaimin1, HU Yanxiao4
    Journal of Vibration and Shock. 2025, 44(6): 137-143.
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    To investigate the effects of a random ice field on the water-entry process of a moving body, a series of experiments on the vertical water entry of a moving body in a crushed ice environment were conducted, integrating the use of a random ice field and high-speed photography technology. The water entry process of vertical moving body was analyzed under both ice-free and crushed ice environment, and the water-entry process is divided into two stages: water-entry impact stage and movement with cavity stage. Additionally, a series water-entry experiments were also conducted with different crushed ice densities environment, the law of influence of crushed ice densities on the evolution of vertical moving body water cavitation is summarized. Results show that during the water-entry impact stage, compared with the ice-free environment, the cavity diameter is larger and the cavity expansion duration is longer at the same depth under the crushed ice environment. During the movement with cavity stage, crushed ice restricts the cavity from contracting. Compared with the ice-free environment, the cavity diameter and length are larger, and the collapse wake is more serious. With the increase of ice density, the closing length and maximum diameter of the cavity increase obviously, the closing time of the surface is delayed, and the velocity attenuation of the moving body is increased. 
  • XU Ping1, 2, HOU Weiqi1, QIAO Shifan3, DONG Hui1, 2, LUO Xiaoguang1, 2, ZHAO Wei1
    Journal of Vibration and Shock. 2025, 44(6): 144-156.
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    To investigate the propagation laws of energy waves generated by nearshore underwater borehole blasting and to evaluate the destructive effects of seismic waves and water shock waves on reservoir dam, as well as the damaging effects of seismic waves on reservoir shore pits, this study was conducted based on the underwater borehole blasting project at the water intake of the Second Water Source Project in Guilin City. Using a fully coupled Lagrangian-Eulerian algorithm, numerical simulations of nearshore underwater borehole blasting were carried out to analyze the changes in propagation patterns and attenuation laws of blasting energy waves, as well as the dynamic response characteristics of the reservoir dam and shore pits. The results indicated that: 1) The attenuation characteristics of the water shock wave peak pressure with the scaled distance charge (Q1/3/R), dam vibration velocity time history curve and the variation pattern of dam peak vibration velocity observed in field tests showed a high degree of consistency with the numerical simulation results. Both field tests and numerical simulations demonstrated that the attenuation characteristics of water shock wave peak pressure closely matched Cole's empirical formula, confirming the reliability of the numerical simulation model for underwater borehole blasting. 2) Based on an intuitive analysis of the propagation and attenuation characteristics of water shock waves in reservoir water and seismic waves in the reservoir bottom rock mass, the propagation process of blasting energy waves was divided into three stages: explosion stage, diffusion stage, and attenuation stage. The influence ranges of seismic waves and water shock waves caused by the propagation of energy waves, with a medium vibration velocity of v=0.1cm/s, were 270m and 206.28m, respectively, and both did not reach the foot of the reservoir dam. 3) The peak pressure of water shock waves significantly attenuated with increasing distance from the explosion center and depth. Based on the blast similarity analogy method, a dual-factor empirical calculation formula for water shock wave pressure, considering both explosion center distance and underwater depth, was established, which can be used to reliably predict the peak pressure of water shock waves at any position in the water area. 4) The propagation of blasting energy waves in the reservoir dam caused significant dynamic responses in the core wall and the dam body. The vibration response in the bottom region of the dam’s blast-facing side was intense, and localized damage occurred in the dam foot area. The peak vibration velocity at the monitoring point at the dam bottom reached 0.17cm/s, which is below the standard limit of 2.5cm/s, indicating that the dam was preliminarily in a safe and stable state; the maximum damage ratio at the dam foot was only 25%. To ensure the absolute safety of the dam, appropriate vibration isolation and protective measures should be considered. 5) The propagation of blast-induced seismic waves in the reservoir shore rock mass triggered sequential dynamic responses on the blast-facing side, bottom, side, and back-blast side of the pit. The peak stress and peak vibration velocity were highest at the top of the blast-facing side of the pit. Close-range high-charge blasting could adversely affect the safety and stability of the shore pit, necessitating strict reinforcement and vibration isolation measures in engineering practice. The findings can also provide a reference for analyzing the propagation laws of energy waves and assessing adverse impacts in similar engineering blasting projects.
  • CIVIL ENGINEERING
  • JING Hongmiao1, 2, 3, ZHAO Wanru3, ZHAO Jian4, AN Luming4, YU Chao4, LIU Qingkuan1, 2, 3
    Journal of Vibration and Shock. 2025, 44(6): 157-167.
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    Wind characteristics at a bridge site in mountain valley are very complicated, which leads to a new problem for the design and construction of long span bridges. To accurately obtain the wind characteristics in mountain valley and their distribution, the terrain model wind tunnel test of a V-shaped canyon where a long span bridge is going to be built with uniform and atmospheric boundary layer inflow conditions was carried out, and the mean and fluctuating wind characteristics at the bridge site under different wind directions were studied. The distribution of wind characteristics at the location of bridge tower and main girder was analyzed. And the main beam 1/6 span and the midspan of the V-shaped canyon in the boundary layer turbulent wind field under the inflow wind characteristics were compared. The results indicate that the wind profile suitable for flat terrain in the relevant wind resistance specifications cannot be directly applied for mountain area, and the range of wind attack angle changes in the canyon is large. The suggested wind attack angle range for V-shaped valleys is -20° to +20°. When the flow direction and the valley orientation are consistent, the turbulence intensity is also smaller, while the turbulence intensity of the leeward side of the bridge is large, so the leeward side of the bridge should be reinforced during the design. The fluctuating wind power spectra at the middle span of main girder and the pylon are in agreement with the von Kármán spectrum. This study could be provided reference for wind resistance analysis and design of long span bridges in similar V-shaped canyon in mountain areas.
  • LU Junlong1, LI Chaofang1, TIAN Penggang2, LI Mingdong1, WU Xiaoqin1,
    Journal of Vibration and Shock. 2025, 44(6): 168-175.
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    The Xi’an City Wall, a quintessential example of heritage architecture with an external brick and internal rammed earth structure, is susceptible to damage due to the stress imposed by crowds atop the wall, posing a threat to its structural integrity. To investigate the dynamic response and underlying damage mechanisms of this wall structure under the influence of crowd-induced loads, in-situ dynamic testing was employed to examine its dynamic properties and responses. Utilizing 3DEC, a discrete element modeling software, a comprehensive three-dimensional numerical model was developed for dynamic analysis, yielding insights into the wall’s response to crowd loads at its summit. The findings from this analysis were then used to assess the structural safety of the wall. The study reveals that the dynamic response intensifies with the elevation of the wall, with the most pronounced effects observed at the top, where vertical responses surpass horizontal ones. As crowd density increases, the wall’s strain becomes more pronounced vertically, particularly above wall openings, near wall piers, and along parapet walls. Therefore, the top of the entrance of the city wall and the top of the wall are prone to damage under the action of high-density crowd load, and necessary monitoring should be carried out.
  • LI Yuqing1, WANG Xin1, LIU Xiaobing1, 2, 3, CHEN Anjie1, CUI Huimin2, 3, 4
    Journal of Vibration and Shock. 2025, 44(6): 176-183.
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    The large-span cylindrical reticulated shell structure is sensitive to wind load. The opening of spacer skylights at the top has a great influence on the wind resistance of the structure. In this paper, the large-span cylindrical reticulated shell structure is studied by the rigid model pressure measurement wind tunnel test method, and the influence of the opening and closing of the top spaced skylight on the shape coefficient, the overall force coefficient and the extreme wind pressure coefficient of the structure under different wind direction angles is analyzed. The results show that the opening and closing of the skylight has little influence on the wind load of the outer surface of the structure, but the influence of the wind load of the inner surface is obvious. The change of the wind load on the inner surface is the main reason for the variation of the wind load of the structure with the opening and closing of the skylight. Compared with the skylight is closed, the overall force of the structure increases by about 34% when the skylight is opened. This effect gradually weakens with the deviation of the incoming flow, and when the deviation is 60°, the effect is basically gone. The vertical overall force of the structure is smaller, with an amplitude reduction of about 47%, and this effect gradually weakens with the deviation of the flow from the span direction, but still exists even when the deviation is 90° (longitudinal flow). Compared with the skylight is closed, the positive extreme wind pressure of the structure increases when the skylight is opened, and the negative extreme wind suction decreases in most areas, but the negative extreme wind suction increases in some areas of the skylight.
  • HE Yuxuan, YIN Tao, WANG Xi
    Journal of Vibration and Shock. 2025, 44(6): 184-190.
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    Bayesian Neural Network (BNN) generally has stronger noise robustness than ordinary neural networks, and has gradually attracted attention in the fields of structural system identification and health monitoring. Currently, relevant literature in this field mainly focuses on the application and architecture design of single-hidden-layer BNN. Multi-hidden-layer architectures with a certain depth usually have stronger generalization capabilities in fitting complex high-dimensional data than single-hidden-layer ones, but research on the optimal design of multi-hidden-layer BNN architectures has not yet been reported in the current literature. This paper aims to carry out optimal architecture design on multi-hidden-layer BNN combined with finite element (FE) model updating problems. A quantitative measure of multi-hidden-layer BNN performance based on evidence logarithm is developed, and an efficient algorithm is also proposed to simultaneously configure the number of neurons in each hidden layer to achieve an optimal architecture design solution of multi-hidden-layer BNN for model updating problems. The correctness and effectiveness of the proposed method are verified by refining the initial FE model of a large-span steel pedestrian bridge utilizing field measured data.
  • HUANG Ke1, 2, LIU Chunfang1, HUANG Dukang1, DAI Lizhao1, WANG Lei1
    Journal of Vibration and Shock. 2025, 44(6): 191-201.
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    In the case of unknown excitation, existing structure identification method based on unscented Kalman filter (UKF) suffered from a large number of unknown parameters, low computational efficiency, and difficulty in updating of the structural state, structural parameters and unknown excitation simultaneously. To resolve these problems, an enhanced UKF method for real – time and simultaneous identification of structural states, parameters and excitations was proposed in this study. By simulating the unknown excitations and unknown parameters as a random walk model, and establishing a uniform state matrix of structural states, structural parameters and external excitations, this method effectively reduces the number of unknown quantities in the identification process and solves the problem that the unknown excitations cannot be updated synchronously. The stiffness degradation is used to identify the structural damage, and the validity of the method is verified based on two nonlinear hysteresis model examples under seismic action, considering the influence of observation noise in the identification process. The results show that the proposed method can not only identify the state, parameters, and external excitation of the nonlinear structure in real time simultaneously, but also track the structural damage in real time.
  • QIAN Hui1, LI Hanyu1, WANG Xiangyu1, ZHAO Hui1, 2, SHI Yifei1
    Journal of Vibration and Shock. 2025, 44(6): 202-212.
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    In order to solve the problem of insufficient bonding performance between traditional bare round SMA bars and concrete substrates, a superelastic Ni-Ti SMA ribbed reinforcement is processed in this paper. A superelastic ribbed SMA bar reinforced ECC beam and four control rectangular cross-section adapted beams were experimentally designed and fabricated, and digital image correlation technology was applied for simultaneous observation and collection to calculate and analyse the surface crack development of the beams. The beams were subjected to four-point bending low circumferential unidirectional cyclic loading tests to investigate the mechanical properties of the beams subjected to bending. The results show that the superelastic hysteresis effect of the ribbed SMA bars after ageing heat treatment is similar to that of the bare round SMA bars, and the superelastic properties are improved. The deformation ductility, ultimate load carrying capacity, self-reinstatement capacity and crack control capacity of ECC beams reinforced with ribbed SMA tendons were significantly improved compared with other tested beams. All the beams did not show any slip or fracture of the tensile tendons during the whole loading process, and the tensile tendons worked well with the concrete. Based on the one-dimensional intrinsic model of the material and specific assumptions, a simplified calculation model of the load carrying capacity of the studied composite beams is deduced and established, and its accuracy is effectively verified.
  • EARTHQUAKE SCIENCE AND STRUCTURE SEISMIC RESILIENCE
  • XU Qikeng1, ZHANG Zhenqian1, LIU Qiang1, WANG Likun2, LI Liang3
    Journal of Vibration and Shock. 2025, 44(6): 213-222.
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    The dynamic interaction between silo structures and grain particles under seismic loading induces dynamic overpressure, which poses a significant safety concern for silos. To address this, a finite element model of a column-supported silo and grain particles was developed based on the extended Drucker-Prager (D-P) model. Vibration table experiments were conducted to validate the dynamic lateral pressure results through comparative analysis. A full-scale silo finite element model was further constructed to examine the influence of various grain parameters on dynamic lateral pressure, with a gray relational analysis performed.Results demonstrate that the extended D-P model effectively captures the trend of dynamic lateral pressure changes, validating the FEM's accuracy.The impact of friction coefficient on dynamic lateral pressure was found to vary with silo height, while the elastic modulus showed the strongest correlation. This study clarifies the mechanisms by which grain parameters affect dynamic lateral pressure and provides valuable insights for selecting parameters in numerical simulations and seismic design of silo structures.
  • HUANG Feng1, 2, L Liqun1, MA Chao1, HOU Chengyou1, GAO Ziqi1, ZHU Guinan1
    Journal of Vibration and Shock. 2025, 44(6): 223-230.
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    The incision of the Yellow River's has led to a decrease in the erosion base level of the Tongde Basin, causing it to transition from a sedimentary to an erosional area, and increasing the frequency of debris flow disasters. Monitoring the formation and movement process of debris flows is beneficial for ensuring the safety of the lives and properties of pastoralists in the valley bottom. Techniques such as the Band-Pass Filter (BP-filter), Fast Fourier Transform (FFT), and Power Spectral Density (PSD) analysis are employed to uncover the time-frequency attributes and energy distribution patterns of debris flow movements. The relationship between the dynamic parameters of debris flows and vibration signals is analyzed by combining monitoring devices such as video cameras, mud level meters, flow rate meters, and pressure sensors. The results indicate that the STA/LTA ratio can effectively respond to debris flow events, with significantly higher R values at the debris flow head compared to the debris flow body. During the occurrence of episodic flows, the STA/LTA ratio exhibits a sharp increase, with monitoring values preceding actual events. Power spectral density can reflect the unstable movement process of debris flows, with mid and high-frequency bands containing more dynamic information compared to low-frequency bands. Distinguishing between debris flows and flash floods based on a single energy threshold is not feasible, as the energy threshold is influenced by the addition of material from bank collapses during the unstable movement of debris flows. The response relationship between seismic signals and single movement parameters such as mud level, flow rate, and velocity of debris flows is poor, while the relationship with mass flow is the most robust.
  • LIANG Yuming1, 2, BAI Yu1, 2, MA Ming3
    Journal of Vibration and Shock. 2025, 44(6): 231-243.
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     In order to solve the issue of zero horizontal stiffness in the sliding process of rigid skateboard bearings, a new type of metal spring isolation bearings was developed. Through pure shear tests of the metal spring components and compression-shear tests of the isolation bearings, the relationship between the restoring force characteristics of the component part and the isolation bearing was studied. The study results indicate that the vertical bearing capacity of the isolation bearing is independent of the horizontal restoring force; the metal spring component has nonlinear elastic restoring force, with the restoring force increasing with displacement. The frictional force of the isolation bearing is related to the vertical pressure, and the energy dissipation effect increases with increasing vertical pressure. A method for calculating the large deformation of curved Euler-Bernoulli beams under boundary constraints was proposed. Using this method and basing on the spring material and dimensions, the force-displacement relationship of the isolation bearing was observed. The computed results with the proposed method agree well with the test data and the simulation results. The proposed method demonstrating reliable calculation accuracy and high computational efficiency.
  • WANG Fei1, 2, LIU Yunhe3, LI Hu1, 4, XUE Bing1, 4, MOU You1, 4, SONG Zhiqiang3
    Journal of Vibration and Shock. 2025, 44(6): 244-253.
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    Seismic input is the foundation of seismic safety analysis for dams, but the influence of canyon scattering effects on dam dynamic response has not been reasonably considered in seismic input. This paper decomposes the total motion field of the canyon site into the free field motion of a flat half space and the scattering field motion of the canyon, which are solved separately. The indirect boundary integral equation method is used to solve the scattering field of the canyon site, and it is superimposed with the free field of a flat half space to obtain the total motion field (ground motion field) of the canyon site. The accuracy of the indirect boundary integral equation method is verified through closed form solutions. Furthermore, the finite element method is used to simulate the interior of the canyon site, and the total motion field at the truncated boundary of the canyon foundation is converted into the equivalent seismic input loads, establishing a wave input method that combines the total motion field with viscoelastic artificial boundaries. The seismic wave input method based on finite element method-indirect boundary integral equation method is applied to numerically solve the ground motion field of a trapezoidal canyon site, and the differences in dynamic response of the canyon under free field wave input and total motion field wave input are analyzed. The results show that there is a significant deviation between the peak displacement and waveform of key position of the canyon under the free field wave input and the exact solution, the maximum errors of horizontal and vertical displacements are 15.6% and 29.3%, respectively. The peak displacement and waveform under the total motion field wave input fit well with the exact solution. The wave input method established in this paper has high calculation accuracy and reasonably considers the scattering effect of canyons, providing a basis for more accurate prediction of the dynamic response of dams on canyons.
  • CHEN Yuxin1, 2, LI Ping1, 2, 3, GAO Zhiyin1, 2, TIAN Zhaoyang4, BO Jingshan1, 2, LI Xiaobo1, 2
    Journal of Vibration and Shock. 2025, 44(6): 254-262.
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    The unique river valley terrain of Beichuan old county town is one of the main reasons for it being the area most severely affected by the Wenchuan Ms8.0 earthquake, indicating that local irregular terrain significantly affects seismic wave propagation and spectral characteristics. In order to investigate the seismic ground motion effects of the valley site on this area in depth, taking the Jianjiang river valley in Beichuan old county town as the study area. Based on regional geological investigation and drilling, two nearly parallel river-oriented profiles are laid out along the left side of the Jianjiang river valley for microtremor testing. The horizontal-to-vertical spectral ratio method is used, combined with field geological investigation and drilling results, to comprehensively analyze the valley terrain effects of Beichuan old county town. The research results show (1) Significant amplification effects of the Jianjiang river valley site, with the predominant frequencies of the Jianjiang river valley soil layer concentrated between 3.89-12.11 Hz, and corresponding peak amplification factors ranging from 2.12-7.26. (2) Most of the H/V spectral ratio curves of the pulsating points exhibit bimodal or multimodal shapes, indicating the existence of two or more wave impedance interfaces at different depths underground. The amplification factors of the points near the river line (Line II) are almost all greater than those near the mountain line (Line I), and the predominant frequencies of the soil layer are almost all lower than those of Line I points. Both lines have impedance boundaries slightly larger around 0.8 Hz and larger around 8 Hz. (3) Integrating the microtremor data with the actual drilling data, a preliminary depth-frequency relationship of the valley area is established. The research results not only provide a reference for the seismic damage research of Beichuan old county town but also accumulate basic data for the in-depth study of valley site effects.
  • TRANSPORTATION SCIENCE
  • JIANG Hongguang1, WANG Xinyu1, MA Chuanyi2, ZHANG Ning2, LIU Shun3, WANG Chuan2
    Journal of Vibration and Shock. 2025, 44(6): 263-271.
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    The mud pumping in subgrade bed of high-speed railway has gradually emerged resulted from the hydraulic-mechanical effect. Studying the critical hydraulic gradient corresponding to the fine particles of the subgrade bed can help to reveal the mechanism of mud pumping. In order to further study the migration and critical hydraulic gradient of fine particles in subgrade bed of high-speed railway, based on the model device for mud pumping of subgrade bed, the dynamic water characteristics and fine particles migration test under cyclic loading was carried out. The development laws of dynamic pore water pressure, hydraulic gradient and turbidity of subgrade bed filler were analyzed, and the relationship between particle size and critical hydraulic gradient of subgrade bed filler was proposed. The results show that under the dynamic loading, the surface layer presents the alternating action of positive-negative excess pore pressure, and the upward hydraulic gradient of “negative pressure pumping” is generated during the unloading. The interlayer shows the upward hydraulic gradient of the combined action of “positive pressure driving” and “negative pressure pumping”. The distribution of fine particles in the surface layer is consistent with the hydraulic gradient, showing a “saddle-shaped” distribution of high at both ends and low in the middle. For the bottom layer, the critical hydraulic gradient for the migration of 0.075 mm particles is 0.052, which is lower than the experimental values of 0.12~0.25 of the interlayer, resulting in the migration of fine particles to the surface layer. The current design specification cannot completely avoid the mud pumping. It is necessary to further reduce the fine particle content in combination with the dynamic load level of the train.
  • DING Wangcai1, 2, ZHANG Jiandong1, GE Feiyuan1, WU Shaopei1, LI Deyang1, LI Guofang1
    Journal of Vibration and Shock. 2025, 44(6): 272-281.
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    To investigate the optimization problem of steel rail profile on small radius curves in heavy haul railways, the wear area and rolling circle radius difference of the outer and inner rails are taken as the optimization objectives. While considering reducing wear, the ability of vehicles to negotiate curves is also optimized. The Kriging theory is used to fit the objective function and obtain the corresponding mathematical model. The NURBS theory is used to parameterize the rail profile, and the second-generation Non-dominated Sorting Genetic Algorithm (NSGA-II) is employed to solve the objective function and obtain the optimized rail profile. The wear performance, dynamic performance, rail rolling contact fatigue, and wheel wear performance of the optimized profile are analyzed to evaluate the optimization profile from multiple perspectives. The results show that the range of design variables significantly affects the objective function. After optimizing the range of design variables, the performance of the obtained optimal profile in terms of wear area and rolling circle radius difference is superior to that of the optimal profile corresponding to the initial range of design variables. The optimized profile outperforms the CN75 profile in terms of wear index, wear power, and rail wear volume. It also exhibits better dynamic performance, such as wheel lateral shift, compared to the CN75 profile, ensuring better safety and stability of train operation. In terms of rail rolling contact fatigue, the optimized profile is superior to the CN75 profile, with the right rail showing the most significant improvement. In terms of wheel wear, the difference in the wear impact on the wheel between the optimized profile and the CN75 profile is small. The overall wear volume of the optimized profile for the outer and inner rails is slightly reduced compared to the CN75 profile, and the wheel wear performance of the optimized profile is better than that of the initial CN75 profile during the early stage of wear.
  • MA Chaozhi1, 2, WANG Yang2, ZHANG Shufang3, ZHONG Jie4, XIAO Hong2
    Journal of Vibration and Shock. 2025, 44(6): 282-290.
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    Rapid identification of rail corrugation is essential for railway maintenance departments to plan maintenance activities. Using carriage inner noise data for quick identification of rail corrugation has significant advantages. To address the challenge of limited labeled carriage inner noise data and the difficulty of general learning from few labeled samples, a two-stage self-supervised rail corrugation recognition model based on "pretraining + fine-tuning" is proposed. First, a large amount of carriage inner noise data from operating subway trains was collected, and a time-frequency diagram dataset was created using wavelet denoising and wavelet transform techniques. During the pretraining stage, a denoising convolutional autoencoder was used to perform representation learning on numerous unlabeled time-frequency diagrams, and optimal pretraining parameters were obtained. In the fine-tuning stage, supervised learning was conducted on a small set of labeled time-frequency diagrams using an "encoder + classifier" approach. Finally, model experiments were carried out, and rail corrugation recognition was evaluated. The results show that the proposed model effectively extracts key features from the time-frequency diagrams. The detection accuracies for "no corrugation," "30-100 mm corrugation," "100-300 mm corrugation," and "30-100 mm + 100-300 mm mixed corrugation" are 95.62%, 96.46%, 92.38%, and 90.37%, respectively.
  • WANG Yiwei, LU Fan, LI Jiasheng
    Journal of Vibration and Shock. 2025, 44(6): 291-297.
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    In order to study the safety and launching accuracyof vehicle-mounted anti-aircraft missile continuous launching on the move, the rigid-flexible coupling dynamic model of launch vehicle was established. The flexibility of frame was considered and different standard grade pavement models were constructed. The accuracy and rationality of the modelling method proposed by this paper were validated against the test results of real vehicle. The dynamic simulation of vehicle on different roads with different speed was carried out to obtain the vibration and outlet attitude data. The results show that the vehicle speed should be limited according to the road conditions, which could improve the stability of the vehicle and reduce the vibration response of the missiles.The initial disturbance caused by uneven pavement is random. In most cases, the missile still has a pitch tendency when exiting the launch barrel, and the launch tube has a certain effect on missile deviation correction on the basis of missile yaw. The influence of wind load on the outlet attitude of missile is small under the coupling action of vehicle-road factors.
  • FAULT DIAGNOSIS ANALYSIS
  • CHEN Xinting1, 2, ZHANG Jun1, 2, LU Dongming2, 3, YING Liuqi2, 3, LI Qiang2
    Journal of Vibration and Shock. 2025, 44(6): 298-305.
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    To address the challenge that traditional supervised learning methods require a large amount of labeled damage data, this paper proposes a reconstruction method for bridge structure vibration signals based on a multi-head convolutional autoencoder. The effectiveness of the vibration signal reconstruction for arch bridges and beam bridges, as well as the variation patterns under different damage states, are analyzed using a damage assessment metric based on mean squared error. The results indicate that the multi-head convolutional autoencoder achieves high accuracy in both signal reconstruction and subsequent damage identification, with the multi-head one-dimensional convolutional structure outperforming traditional one-dimensional convolutional structures in terms of damage detection accuracy and sensitivity. The proposed method is validated through finite element simulation data for arch bridges and damage measurement data for continuous beam bridges, demonstrating its ability to accurately identify the damage development trends in bridge structures. Furthermore, the method exhibits robust performance in noisy environments, providing a valuable reference for the analysis of structural health monitoring data in bridge engineering.
  • YUAN Jiuhai, ZHANG Qing, ZHANG Jianqun, FENG Wenzong, SUN Yuantao
    Journal of Vibration and Shock. 2025, 44(6): 306-317.
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    The number of components and fault types of the shore bridge gearbox is large, and the fault data is difficult to obtain, and its diagnosis faces the problem of small sample and multiple classification. To address the above problems, a fault diagnosis method based on frequency domain vibration image (FDVI) and conditional denoising diffusion probabilistic model (CDDPM) is proposed. Firstly, the obtained vibration signals are transformed into images using the FDVI method, fully characterizing the characteristic information of vibration signals for each fault. Then, the CDDPM is used to expand the small sample data, and the labeling information is input to the model to control the generation of fault sample categories, while skip-layer sampling is used to accelerate the sample generation speed. Input the expanded sample set into a convolutional neural network classifier for training to improve the classifier's performance in diagnosing multi class faults with small samples. The small-sample diagnostic experiments on the 17 faults in the CWRU dataset and the 29 faults in the shore bridge scaling experimental platform dataset show that: after the sample expansion, the fault recognition rate of the CWRU dataset is increased from 89.86% to 99.30%; the fault recognition rate of the shore bridge dataset is increased from 68.63% to 99.30%. The above analysis shows that the proposed method can accomplish the task of multi-class fault diagnosis for shore bridge gearboxes under small sample conditions.
  • YU Lichao, HUANG Yuan, WANG Chenglong, LUO Huageng
    Journal of Vibration and Shock. 2025, 44(6): 318-328.
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    In vibration-based gearbox fault diagnosis, accurately extracting periodic transient impact signals caused by defects is critical for achieving fault diagnosis. However, the vibration signals measured in practice often contain various interference components, making the extraction of transient impacts quite challenging. To address the issue, this paper proposes a sparsity-enhancing regularization method based on harmonic features. Firstly, a weighted sparse optimization model for gearbox fault signals is established. Secondly, an indicator reflecting the strength of periodic transient impact signals is constructed based on harmonic features. Finally, reweighted regularization is implemented based on the indicator to penalize interference signals, thus enhancing the noise reduction capability. The analysis results of both simulated signals and practical cases verify that the proposed method outperforms other sparse decomposition methods and conventional signal processing methods in terms of the reconstruction accuracy for fault signals, thereby providing more accurate gearbox fault diagnosis results.