28 October 2024, Volume 43 Issue 20
    

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  • LI Nailu1, XU Wentao1, LUO Ziwei1, MU Anle2
    Journal of Vibration and Shock. 2024, 43(20): 1-9.
    Abstract ( 214 ) Download PDF ( 170 )   Knowledge map   Save
    The behaviors of nonlinear aeroelasitc system show limit cycle oscillations under smooth airflow and irregular, nonlinear, randomly varying oscillations under the turbulence. A fractional-order direct adaptive controller (FDAC) based on output feedback is proposed to suppress the vibration of nonlinear aeroelastic system under wind disturbance. First, the FDAC is designed based on fractional calcus and direct adaptive control theory. Then, the appropriate range of fractional order parameters are deduced. The advantage of FDAC on aeroelastic control and disturbance rejection is theoretically analyzed, compared with integral order direct adaptive controller (DAC). The stability of proposed controller is proved by Kalman-Yacubovich lemma. Simulation results reveal that the proposed FDAC can significantly improve the performance of vibration control and disturbance rejection, under large and random wind disturbance for nonlinear aeroelastic system. The simulation results also verify the theoretical inclusions. 
  • SUN Zhi'ang1, 2, YANG Xinwen1, 2, ZHAO Wenbo3, QI Zhigang4
    Journal of Vibration and Shock. 2024, 43(20): 10-17.
    Abstract ( 106 ) Download PDF ( 71 )   Knowledge map   Save
    Special boundary conditions such as high temperature difference cause additional track-bridge deformation, which affects track geometry and increases instability risk of high-speed train. Based on the long-term monitoring data and field testing of a certain Yangtze River bridge in China, extremes of temperature and wind speed data since the operation were introduced and characteristics of track geometry and dynamic responses were analyzed. A finite element model to analyze the influence of additional deformation on track geometry was established. United simulation method, which is composed of Finite Element Method and Multi-body Dynamics Analysis, laid the foundation of explaining the influence of temperature difference on dynamic responses of high-speed train. The results show that: (1) The long-term monitoring data show that the maximum temperature is 41.3℃ and the minimum temperature is -8.9℃; the maximum temperature sudden rise is 4.9℃, and the maximum temperature sudden fall is -10.7℃. (2) Track geometry and TQI index of the Yangtze River Bridge was in a good state. Wheel-rail responses and vehicle vibration satisfied requirements. (3) The extreme temperature difference causes the rail expansion to reach a maximum of 630.19mm, and the maximum longitudinal level of rail to reach 19.89mm, which is beyond the limit, resulting in eccentric loadings. The vertical Sperling index in the areas of piers and Rail Expansion Joints reaches 2.72, and lateral swing of the vehicle also becomes more obvious.
  • YUAN Pingping1, MAN Zhen2, ZHAO Zhoujie1, REN Weixin3
    Journal of Vibration and Shock. 2024, 43(20): 18-25.
    Abstract ( 75 ) Download PDF ( 64 )   Knowledge map   Save
    To reduce the impact of initial instantaneous frequency and signal noise on the variational nonlinear chirp mode decomposition (VNCMD), a data-driven adaptive variational nonlinear chirp mode decomposition (DDAVNCMD) is proposed in this paper. The modal number of the response signal is obtained by the proportion of modal energy, and the derivative normalization algorithm is used to preliminarily estimate the initial instantaneous frequencies of the modal components. An iterative time-varying filter is also added to reduce the noise effect. Based on this, the response signal is then subjected to VNCMD. The proposed method is validated through single-component and multi-component analytic signals, as well as a cable structure experiment. The research results indicate that the instantaneous frequency identification method based on DDAVNCMD has good accuracy and anti-noise performance.
  • HUANG Peng, ZHOU Hualiang, LI Ziyu, LIN Huatan
    Journal of Vibration and Shock. 2024, 43(20): 26-34.
    Abstract ( 64 ) Download PDF ( 35 )   Knowledge map   Save
    Windborne plate-type debris is one of the main factors causing damage to the building envelope in wind disasters, and there are usually mass eccentricities due to factors such as uneven materials. A numerical motion model of plate-type debris considering mass eccentricity was established, and the flight attitudes, trajectories and velocities of the debris under the influence of different centroid positions and initial wind attack angles were studied, and the influence of debris with eccentric mass on the crowds and buildings was analyzed. The results showed that the model is accurate and efficient, and can be adapted to the rapid simulation of plenty of debris with different initial parameters; mass eccentricity exacerbates the reverse flip of the plate-type debris in motion, and the rotation dissipates the translational energy thereby reducing the velocity of the impact; during takeoff, the center of mass is biased down, and the debris generally falls faster, while a higher center of mass is more likely to cause the trajectory to be dispersed; moreover, the mass eccentricity is critical to the attitude of the debris impacting the building envelope.
  • YANG Menggang1, 2, ZHANG Yu1, 2, MENG Dongliang1, 2, HU Shangtao1, 2
    Journal of Vibration and Shock. 2024, 43(20): 35-44.
    Abstract ( 51 ) Download PDF ( 59 )   Knowledge map   Save
    By conducting impact tests on a steel column specimen, the influences of impact mass and velocity on the impact responses were explored. Numerical simulation of the impact test was carried out based on ABAQUS/Explicit, furthermore, the effects of specimen slenderness ratio, hammer material and axial compression ratio on the dynamic response of the specimen due to impact loading were investigated. Based on the energy principle, a method for calculating the equivalent impact force for steel columns under horizontal impact was proposed. The results show that the impact force increases with the impact mass and velocity, and is more significantly affected by the impact velocity. With the decrease in specimen slenderness ratio, the peak impact force increases while the displacement decreases; a smaller axial pressure is beneficial for reducing the dynamic response of the specimen. The dynamic responses of the specimen under the impact of the aluminum hammer are similar to that of the steel hammer. In comparison, the responses under the impact of the rubber hammer are greatly reduced. When applying the equivalent impact force obtained by the proposed method to the impact position of the column, the errors of the calculated maximum responses such as strain and displacement of the column are within 15% compared to the corresponding responses under impact. 
  • WU Zaixin1, YUAN Zhe2, YANG Jianjin2, QU Shuai2, LOU Panming2, YANG Jizhong3, ZHU Shengyang2
    Journal of Vibration and Shock. 2024, 43(20): 45-53.
    Abstract ( 41 ) Download PDF ( 25 )   Knowledge map   Save
    he increasing speed of underground railways necessitates posed higher demands for controlling train-induced environmental vibrations. This study focuses on the vibration issues induced by trains running in tunnels at 350 km/h. Utilizing the vehicle-track coupled dynamics theory and finite element methods, a prediction model for train-induced vibrations in underground railways was built and subsequently validated through on-site vibration tests. The study comprehensively examines the influence of the width, depth, and material properties of wave impeding blocks (WIB) on vibration isolation performance. Results indicate that installing horizontal WIBs in the soil above tunnels significantly reduces ground vibrations caused by train movements. Notably, WIBs positioned close to the vibration source offer prominent isolation effects for vibrations above 5 Hz. The width and depth of the WIB directly correlate with its vibration isolation capability, though excessive dimensions may amplify distant ground vibrations. Among evaluated materials, porous polystyrene WIBs outperform rubber, fine sand, and C30 concrete in terms of vibration isolation, especially within the 5-200 Hz frequency range.
  • LIU Xiuquan, LIU Zhaowei, WANG Kunqian, CHANG Yuanjiang, CHEN Guoming
    Journal of Vibration and Shock. 2024, 43(20): 54-61.
    Abstract ( 28 ) Download PDF ( 34 )   Knowledge map   Save
    The dynamic characteristics of workover riser system with workover tools under the excitation of workover vessel are studied. A mechanical model of workover riser and workover tool is established based on beam theory. The boundary constraints such as workover vessel, tension system and soil are applied to the mechanical model. The contact model is established by gap element method. A numerical model is established by finite element method and Newmark-β method. The dynamic response of workover riser system is analyzed. The results show that the difference between the axial displacement of workover riser and the axial displacement of workover tool is obvious when workover vessel is in heave motion. The workover riser and workover tools are prone to contact regularly when workover vessel is in surge motion. The movement of workover riser and workover tool is almost the same when workover vessel is pitching.
  • WEI Qiang1, LI Zifeng1, ZHANG Jie1, 2
    Journal of Vibration and Shock. 2024, 43(20): 62-74.
    Abstract ( 99 ) Download PDF ( 90 )   Knowledge map   Save
    In this paper, a mathematical model of the drillstring vibration in the process of an up-jar operation in vertical wells was established and solved. The three stages of the drillstring vibration were described, and a mathematical model was made to explain them during an up-jar operation. ① During the tensile energy storage stage, the static analysis of the drillstring was carried out. ② During the pressure relief stage, the Eigenfunction Function Expansion Method was used to find an analytical solution. ③ During the impact stage, the compact difference method was used to solve the mathematical model. After processing with the low-pass filtering method, the dynamic release force discovered using the aforementioned method is in good agreement with the corresponding analytical solutions and Abaqus results. The relationship between the jar initiation tensions, the up-jar’s location, the drilling fluid viscosity, the effective distance of the mandrel, and the dynamic release force were investigated.
  • L Yang1, ZHANG Fanxing1, ZHANG Yike2
    Journal of Vibration and Shock. 2024, 43(20): 75-84.
    Abstract ( 80 ) Download PDF ( 27 )   Knowledge map   Save
    The vertical load-bearing capacity of Magneto-Rheological Elastomer (MRE) isolation bearings is low. However, vertical load has significantly influences on the mechanical performance of the MRE bearings, which limits the engineering applications of MRE bearings. By adding vertical rods to bear vertical loads and a constant magnetic field with permanent magnets, an isolation bearing with a structure of MRE sheets and steel plates alternately stacked and bi-directional adjustable shear stiffness was designed and built. The finite element method was used to analyze the effects of MRE layer thickness, permanent magnet thickness, and magnet placement on the bearing's magnetic circuit. The bearing has a core diameter of 60 mm, consisting of 26 layers of MRE and 25 layers of steel plates. Mechanical performance tests of the bearing were conducted under sinusoidal waves of different frequencies and amplitudes under different currents and weights. Based on the test results, the Particle Swarm Optimization algorithm was used to identify the parameters of the Bouc-Wen model of the bearing. The results show that the MRE bearing has a high vertical load bearing capacity and stable mechanical performance. The Bouc-Wen model can accurately describe the hysteresis characteristics of the bearing, and the fitting data is in good agreement with the experimental results.
  • JIANG Xudong1, NIU Qiancheng1, TENG Xiaoyan2, WU Ziwang1, WU Hao1, LIAN Shanli3
    Journal of Vibration and Shock. 2024, 43(20): 85-93.
    Abstract ( 87 ) Download PDF ( 44 )   Knowledge map   Save
    This paper proposes the isogeometric-analysis-based stiffness and mass spreading method for topology optimization of trusses under transient loads to achieve their lightweight design with high load-bearing capability. Through the energy equivalence principle, both the stiffness and the mass matrixes are projected to the isogeometric background mesh, respectively. Subsequently, the isogeometric FEM of trusses is developed for transient analysis, which is effectively solved by unconditionally stable implicit Newmark’s scheme. We model the dynamic layout optimization of trusses for compliance minimization while constraining the volume of trusses. Based on the discretize-then-differentiate approach, the corresponding adjoint equations are derived for the transient problem, such that the sensitivity analysis is consistently computed on the discretized system in both space and time. Then, several 2D and 3D numerical examples are presented to verify the proposed method. The numerical results demonstrate that this approach has the potential to perform the layout design of trusses for the maximal dynamic stiffness, and thereby provides the wide application prospects in practical engineering. 
  • DONG Shaojiang, HUANG Xiang, XIA Zongyou, ZOU Song
    Journal of Vibration and Shock. 2024, 43(20): 94-105.
    Abstract ( 133 ) Download PDF ( 47 )   Knowledge map   Save
    A novel fault diagnosis method is proposed, which combines a multi-scale convolutional neural network (MSCNN) with a bi-directional long short-term memory network (BiLSTM) using an attention mechanism. This approach addresses the issue of feature extraction in traditional fault diagnosis methods, which often result in limited representation of fault information and the inability to deeply explore fault characteristics under complex working conditions. Firstly, the method employs pooling layers and convolutional kernels of different sizes to capture multi-scale features from vibration signals. Then, a multi-head self-attention mechanism (MHSA) is introduced to automatically assign different weights to different parts of the feature sequence, further enhancing the ability to represent features. Additionally, the BiLSTM structure is used to extract the internal relationships between features before and after, enabling the progressive transmission of information. Finally, the maximum-kernel mean discrepancy (MK-MMD) is utilized to reduce the distribution differences between the source and target domains at various layers of the pre-trained model, and a small amount of labeled target domain data is used to further train the model. The experimental results show that the proposed method has an average accuracy of 98.43% and 97.66% on the JNU and PU open bearing datasets, respectively, and the method also shows a very high accuracy and fast convergence speed on the bearing fault dataset (CME) made by Chongqing Changjiang Bearing Co. and provides a practical basis for the effective diagnosis of vibration rotating component faults. 
  • YANG Jing1, 2, PAN Wen1, 2, ZHANG Yanyan3, CAI Zheng1, 2
    Journal of Vibration and Shock. 2024, 43(20): 106-118.
    Abstract ( 45 ) Download PDF ( 46 )   Knowledge map   Save
    A new type of variable stiffness rubber bearing suitable for isolating three-dimensional earthquake or vertical vibration is proposed on the basis of the mechanical behavior of the rubber bearing, and the stiffness matrix analysis method that can solve the mechanical problem of non-homogeneous body of the variable stiffness bearing is described. Firstly, based on the analytical solution of the commonly used rubber bearing and the nonlinear response analysis of the compression shear test, the stiffness matrix analysis is used to calculate the test bearing, and the results are highly consistent with the test values, which verifies that the calculation accuracy of the method is high. Then, the results of the three kinds of bearings are compared: under the same external load and material parameters, the force and deformation of the thick bearing are the largest, and the force and deformation of the variable stiffness bearing and common bearing are significantly lower than that of the thick bearing; under different axial pressures, the P- effect is manifested as follows: the force and deformation of the thick bearing and the horizontal stiffness are most significantly affected by the axial pressure, while the variable stiffness bearing and the common bearing are less affected by the axial pressure. Finally, the calculation example shows that the vertical stiffness can be optimized by adjusting the variable stiffness bearing. In conclusion, the variable stiffness bearing has a better bearing capacity for force and deformation, and provides a simple and practical solution for three-dimensional seismic isolation (vibration).
  • XU Zexin1, AN Chen1, XIE Zhi1, ZHANG Jixiang2, LIM Frank3
    Journal of Vibration and Shock. 2024, 43(20): 119-127.
    Abstract ( 54 ) Download PDF ( 27 )   Knowledge map   Save
    Steel Catenary Risers (SCRs) serve as essential components for supporting offshore platforms and other crucial equipment. Ensuring the structural integrity and safety of SCRs are paramount during prolonged operations in extreme marine environments. Conducting resonant bending fatigue tests on the risers has emerged as a requisite evaluation standard to guarantee their safe operation under harsh conditions, and it also forms the basis for subsequent predictions of fatigue life and analysis of failures. This study focused on deriving and solving the natural frequency and mode functions of the resonance system under different constraint conditions for two specific types of SCRs, and analyzes the effects of pipeline length, pipeline wall thickness, eccentric block and counterweight mass on the natural frequency of the resonance system. Subsequently, full-scale resonant bending fatigue tests were conducted under different specific operating conditions, and the vibration response characteristics of the SCRs with different spans and internal pressures in the full-scale resonant bending fatigue test system were simulated. The integration of theoretical analysis, finite element calculations and results from resonant fatigue tests revealed that the pipeline length and the counterweight constraints at both ends are critical parameters affecting the first-order natural frequency of the resonance system, especially the impact is particularly pronounced when the pipe length is short and the wall thickness is thin. Additionally, internal pressure and an increasing span will decrease the natural frequency of the resonance system, and a shorter support span will result in a higher natural frequency of the system. These analytical results provide an important reference basis for the structural design and optimization of the test plan of the resonant bending fatigue test system of SCR.
  • WANG Jinnuo, CHEN Zhengshou
    Journal of Vibration and Shock. 2024, 43(20): 128-139.
    Abstract ( 47 ) Download PDF ( 33 )   Knowledge map   Save
    The vortex-induced vibration triggered by the coupled effect of wave and current plays an important role in causing the fatigue damage to slender and flexible marine structures such as marine risers, however the study about the characteristics of axial hydrodynamic associated with the wave-induced and current-induced vibrations along the pipe is still scare. In this paper, the volume of fluid (VOF) method is used to capture the free surface, and the numerical wave tank is established. Based on a two-way fluid-structure coupling method, the simulations of a flexible pipe system subject to the wave-current coupled effect are carried out, and then a comparative analysis about the effects of wave and current loads on the pipe’s vibration characteristics is performed. The results about cases subject to wave load show that the vibration amplitude of the flexible pipe increases gradually with KC number, and that the apparent frequencies corresponding to the in-line and cross-flow dominant vibration modes are multiples of those associated with incident wave. The wave force is significant near the free surface and the axial time-averaged values of hydrodynamic coefficient show various distribution features along different pipe segments. In the case of wave-current imposed simultaneously, the corresponding variation trends of amplitude are consistent with those related to the cases subject to current only. Subsequently, the corresponding displacements become more regular than those observed in which only wave load is applied. The in-line frequency is predominated by the wave frequency, and the cross-flow vibration frequency is characterized by a dominant frequency and two subordinate frequencies. It is worth noting that the discrepancies between dominant frequency and two subordinate frequencies are multiples of the wave frequency. Finally, comparing the vortex patterns along the pipe span related to four typical locations in the cases subject to wave and wave-current loads respectively, it is found that the presence of the current can accelerate the vortex release and also act as a key factor to control the type of vortex shedding.
  • ZHENG Gang1, 2, XIAO Jianchun1, 2, GUO Hua1, 2, MA Kejian1, 2, QIU Yun3
    Journal of Vibration and Shock. 2024, 43(20): 140-149.
    Abstract ( 60 ) Download PDF ( 45 )   Knowledge map   Save
    Scaled model impact tests are essential for assessing steel pipe concrete's impact resistance in its original proportions. The material's dynamic strength and the prototype structure's dynamic strength in the scaled model experiments of the steel pipe concrete columns do not satisfy the similarity ratio relationship due to the influence of the strain rate effect under impact. This causes a degree of error when the results of the scaled experimental model are extrapolated to the impact performance of the prototype structure. Based on the DLV (density, geometry, impact velocity) dimension system, 1/2, 1/4, and 1/8 scaled-down models for the lateral impact of large steel-tube concrete columns were created. The Workbench/LS-DYNA software created a finite element model to simulate the lateral impact of a circular steel pipe concrete column. After confirming the model's accuracy, the dynamic yield stress similarity was analyzed using steel and concrete strain rate-sensitive equations. Subsequently, the similarity ratio coefficients were recalculated. The results indicate that by taking into account the similarity in dynamic yield stress of the materials, the errors in contact force, maximum deformation, yield stress, impact velocity, and time course curve agreement of the scaled-down model of steel-pipe concrete columns, which reflect the impact performance of the original-size structure, are further minimized. Notably, the maximum deformation errors are significantly reduced, with all errors falling within 1.5 percent. In conclusion, the similarity of the materials' dynamic yield stress reduces the scaled-down model for steel-tube concrete columns' error in presenting the original-size structure's impact performance.
  • YANG Ke1, 2, ZHENG Shizhang1, 2, LIU Wenjie1, 2, 3, XU Rijie1, 2, ZHANG Zhainan1, 2, LIU Shuai1, 2, CHI Xiaolou1, 2
    Journal of Vibration and Shock. 2024, 43(20): 150-161.
    Abstract ( 56 ) Download PDF ( 36 )   Knowledge map   Save
    In order to investigate the mechanical response and energy dissipation characteristics of coal-rock composite specimens under cyclic impact, a Split Hopkinson Pressure Bar (SHPB) experimental system was employed. Five different impact velocities were designed for cyclic impact compression experiments on coal-rock composite specimens. Comparative analyses were conducted to examine the dynamic stress-strain relationships, energy dissipation characteristics, and failure features of the composite specimens at different impact velocities. The research results indicate that under cyclic impact, coal-rock composite specimens exhibit a pronounced critical effect. When the impact velocity is below the critical velocity, the dynamic compressive strength rapidly decreases in the early stage of the impact, and the rate of change in peak strain decreases with increasing impact velocity. During cyclic impact, the total absorbed energy and fractal dimension of the specimens gradually increase, reaching their peak values at the critical velocity, after which both parameters decrease. Beyond the critical velocity, under equivalent total absorbed energy, the degree of damage to coal-rock formations under cyclic impact is higher than that under a single impact. With a coal-rock strength ratio of 1:2, as the total absorbed energy increases, the rock transitions from accumulating and transmitting energy to intensifying composite body damage. Under impact, the composite body exhibits tensile and splitting failure. Under low-speed conditions, macroscopic cracks mainly initiate at the coal body end face far from the bonding surface. As the impact velocity increases, cracks also appear on the side of the rock away from the bonding surface. According to the region of instability, the failure types of the composite body are classified into coal body instability and composite body instability, and under cyclic impact, the composite body exhibits composite body instability failure. The research results provide a fundamental basis for the stability control of dynamic pressure roadways and surrounding rock in weak rock layers.
  • TONG Jinyu, TANG Shiyu, ZHENG Jinde, YIN Zhuangzhuang, PAN Haiyang
    Journal of Vibration and Shock. 2024, 43(20): 162-171.
    Abstract ( 51 ) Download PDF ( 23 )   Knowledge map   Save
    Aiming at the problem that deep residual network (ResNet) cannot diagnose accurately in noisy environment, a method based on direct fast iterative filtering (DFIF) and an adaptive deep residual network (AResNet) is proposed. The method is applied to the fault diagnosis of rotating machinery in noisy environment. Firstly, different intensities of noise are added to the collected vibration signal, and then several Intrinsic Mode Function (IMF) components are obtained through DFIF decomposition. The IMF component with the smallest comprehensive evaluation index value is selected as the input sample. Secondly, Adaptive Residual Building Unit (ARBU) is proposed, which identifies the optimal coefficients of each channel, adaptively amplifies fault sensitive features and suppresses irrelevant features, and can better replace traditional Residual Building Unit (RBU). Finally, AResNet is constructed based on ARBU, and the input samples are processed through AResNet to obtain fault diagnosis results. The proposed method is applied to the fault diagnosis of rotating machinery under noisy backgrounds and validated in two different data sets. The results indicate that the proposed method has higher noise robustness, stability and better computational efficiency compared to existing methods. And it can better solve the problem that it is difficult to effectively mine the fault features of rotating machinery under noise backgrounds.
  • ZHUANG Peng1, 2, 3, YANG Jianing1, ZHANG Guowei1, 2, 3
    Journal of Vibration and Shock. 2024, 43(20): 172-182.
    Abstract ( 51 ) Download PDF ( 58 )   Knowledge map   Save
    Three-dimensional (3D) isolation of lattice shell structures is a vital research focus at present. Previous studies concentrated on passive 3D isolation bearings without adjustable real-time control capacities. To address the issue, magnetorheological negative stiffness dampers (MRNSDs) were combined with prepressed spring devices (PSDs) in parallel to form a vertical isolation bearing (MRNSD-PSD) with an adjustable damping force. Based on an objective of extending natural period in the vertical direction, a set of control strategy and implementation method of MRNSDs were established, which was used to simulate the cyclic behavior of the proposed damping device. A single-layer spherical lattice shell with surrounding columns was used as a prototype structure. A semi-active isolation system with MRNSD-PSDs and two different passive isolation systems were separately used for the target structure to improve its seismic behavior. The seismic responses of the controlled and uncontrolled structures were analyzed via numerical modeling. The simulation results indicate that all the three different isolation systems are effective in mitigating structural responses, whereas the semi-active isolation system provides superior control effects on vertical accelerations and displacements to the passive isolation systems.
  • ZHANG Congcong1, 2, ZHOU Yuzhe3, MEN Rixiu4, FU Xiaorui1, 2, FENG Zemin1, 2, CAI Changwang1, 2
    Journal of Vibration and Shock. 2024, 43(20): 183-191.
    Abstract ( 34 ) Download PDF ( 10 )   Knowledge map   Save
    The circumferential oil-groove on the floating ring bearing has an important effect on the distribution of the outer oil film pressure, which leads obvious nonlinear vibration for the high-speed and light-loaded turbocharger rotor. Based on the fluid lubrication theory and finite element method, a comprehensive model, including the dynamic equation of the TC rotor, the transient form of thermal energy balance of FRBs, the viscosity-temperature equation of the lubricating oil and the thermal deformation equation of FRBs are established, and the corresponding solving strategy is proposed. The accuracy and reliability of the comprehensive model are verified by the experimental results. Taking the turbocharger rotor system for a diesel engine as an example, the transient vibration response in frequency domain of rotor system with different circumferential oil-groove widths and under different inlet oil temperatures is studied by means of three-dimensional vibration waterfall. It shows that the circumferential oil-groove width is increased for 2.4 to 4.8 mm, the rotational speed range of the inner oil film whip/whirl is reduced, and the inner oil film whirl amplitude decreases greatly under different inlet temperatures. However, with the increase of the width of the circumferential oil-groove and the inlet oil temperature, the bearing capacity of the outer film decreases, which leads to a rigid movement of the rotor system, that is, zero-frequency vibration. The amplitude of zero-frequency vibration is higher than that of low-frequency vibration(subsynchronous), which becomes the dominant frequency. when the circumference groove width increases from 2.4 to 4.8mm and the inlet oil temperature is 50°C, the maximum dimensionless vibration amplitude of the rotor system decreases by about 67%, 75% and 83%, respectively. When the inlet oil temperature is 90°C, the maximum dimensionless vibration amplitude of the rotor system decreases by about 38%, 75% and 82%, respectively. When the inlet oil temperature increases to 130°C, the maximum dimensionless vibration amplitude of the rotor system decreases by about 67%, 75% and 79%, respectively. Therefore, for different inlet oil temperatures, the vibration amplitude of the rotor system can be greatly reduced by the circumferential oil-groove, which is conducive to improving the stability of the rotor system. The conclusion can provide theoretical reference for the parameter design of the circumferential oil-groove for the floating ring bearing.
  • JIANG Xueliang1, 2, YANG Hui1, 2, YU Lei2, 3, QIN Shihui2, SHEN Bo2, WANG Haodong2, LIN Hang4
    Journal of Vibration and Shock. 2024, 43(20): 192-199.
    Abstract ( 35 ) Download PDF ( 23 )   Knowledge map   Save
    Based on the shaking table model tests of a shallow-buried and unsymmetrial pressure tunnel with and without rubber damping layer whose geometric similarity ratio is 1:20, the damping coefficient change laws of rubber damping layer on the tunnel lining’s acceleration and strain were studied and the seismic reduction effect of the rubber damping layer were evaluated. The research conclusion is as follows. (1) The rubber damping layer does not change the trend of the acceleration time history curve at the inverted arch, but significantly reduces its peak horizontal and vertical acceleration response. Regardless of the type of seismic wave, the intensity of seismic excitation, and the location of the tunnel lining, the rubber damping layer can significantly reduce the horizontal and vertical acceleration re-sponse.(2)Regardless of the type of seismic wave and excitation intensity, the horizontal and vertical acceleration damping coefficients of the left arch shoulder of the tunnel lining are much larger than those of the right arch shoulder, which is related to the tunnel being in an eccentric compression state. The impact of seismic wave types on the horizontal ac-celeration damping coefficient is greater than that on the vertical acceleration damping coefficient. (3)There is no significant correlation between the acceleration damping coefficient and the seismic excitation intensity, but from a trend perspective, as the excitation intensity increases, the damping coefficient tends to decrease. (4)Regardless of the type of seismic wave, the intensity of seismic excitation, and the location of the lining, the rubber damping layer has a significant reduction effect on the maximum and minimum principal strains. There is no significant correlation between the maximum and minimum principal strain damping coefficients of the lining and the excitation strength, but overall, the damping coefficient shows a trend of weakening with the excitation strength. (5)The rubber damping layer can play an excellent damping effect in shallow-buried and unsymmetrial pressure tunnel, and its damping effect is closely related to seismic strength, material parameters of the damping layer, and stress environment. These conclusions can provide a certain reference for the application of rubber damping layer in tunnel engineering.
  • FAN Lili, JIANG Bin, ZHAO Peiyi, LI Shihang
    Journal of Vibration and Shock. 2024, 43(20): 200-212.
    Abstract ( 45 ) Download PDF ( 13 )   Knowledge map   Save
    The transfer and transformation of materials during milling under vibration is the key to revealing multi temporal of surface formation. Based on dynamic cutting behavior of milling cutter, the material flow structure was constructed, and transfer and transformation relationships between each component were revealed. Quantitatively characterize instantaneous cutting state of each node in the flow structure with parameters such as the structure, cutting motion, and cutting force. The adjacency matrix of adjacent nodes in the flow structure was constructed, and transfer relationship between adjacent nodes was clarified. Using root mean square, kurtosis, dominant frequency and fractal dimension, dynamic of internal nodes in material information flow were revealed. The input end, cutting layer node, and output end of material information flow were experimentally verified. The results showed that above method could reveal material transfer and transformation of milling process under machine tool drive, providing a basic model for milling process design.
  • ZHANG Zhenhai1, TONG Bo1, QU Duo2
    Journal of Vibration and Shock. 2024, 43(20): 213-220.
    Abstract ( 37 ) Download PDF ( 25 )   Knowledge map   Save
    In order to achieve precise simulation of the flow field and sound field around the rudder and wing of an underwater vehicle during rudder rotation, based on the bidirectional fluid solid coupling theory, the flow field is calculated by using the DES turbulence model, and the fluid-structure interaction boundary is treated by using the automatic matching layer technology to analyze the fluid-structure interaction characteristics of the rudder-wing combined structure in the rotating process, the accuracy of which has been verified by comparing with model experiments. On this basis, the effects of rudder angle, concentrated loads, water filling inside the rudder, and flow velocity on structural sound radiation were studied. The results show that the increase of rudder angle increases the non-uniformity of the flow field, reduces the stiffness of the rudder-wing structure, and exacerbates the vibration of the airfoil, which contribute to the increase of total sound pressure level and vibration acceleration level; for periodic excitation with equal amplitude, the more concentrated the load distribution, the greater the contribution to sound radiation; filling the rudder with water can reduce the amplitude of sound pressure in the mid to high frequency range, but it will increase the number of line spectra of structural sound radiation. In addition, the increase of flow velocity will increase the sound radiation.
  • MA Wenyong1, 2, 3, WANG Hepeng1, JI Yinfeng4, ZOU Chuang4
    Journal of Vibration and Shock. 2024, 43(20): 221-228.
    Abstract ( 60 ) Download PDF ( 22 )   Knowledge map   Save
    Aiming at the problem of wind-induced torsional aerodynamic instability of single-axis trackers, this study used a full aeroelastic model, and reproduced the phenomenon of torsional aerodynamic instability of the single-axis tracker in wind tunnel test. Through the analysis of torsional response and the critical wind speed, the vibration characteristics of the single-axis trackers are clarified. The results show that torsional aerodynamic instability occurs in the tilt angle range of -45°~45°, and the critical wind speed is higher in tilt angle of 0°,when the module is placed horizontally, than that in the other tilt angles . Damping has little effect on the critical wind speed at small tilt angles, and increasing damping at large tilt angle can increase the critical wind speed. With the increase of the angle between the incoming flow and the normal direction of the single-axis tracker (wind direction), the critical wind speed gradually increases. The vibration of the wake end of the single-axis tracker under oblique wind is more severe than that of the windward.
  • LI Xingjian, DIAO Yansong, L Jianda, HOU Jingru
    Journal of Vibration and Shock. 2024, 43(20): 229-237.
    Abstract ( 43 ) Download PDF ( 29 )   Knowledge map   Save
    When using vibration response and deep learning for structural damage identification, the problems such as requiring more data of measuring points, low accuracy of damage identification, and over-fitting of the network will be encountered. Therefore, a novel structural damage identification method based on Convolutional Neural Networks ( CNN ) -Gated Recurrent Unit ( GRU ) parallel neural network are presented in this paper. Firstly, the Generalized S Transform ( GST ) is performed on the measured response signal to obtain the GST time-frequency diagram. Then, CNN and GRU are used to extract time-frequency features and temporal features from time-frequency diagrams and response signals, respectively. The time-frequency features and temporal features are spliced and input into the fully connected layer and Softmax classifier for structural damage identification. The verification results of the model test data of offshore wind power supporting structure under displacement excitation show that the proposed method only needs the response signal of one measuring point and has higher identification accuracy and efficiency than other similar methods. 
  • ENG Ruizhe1, 2, FENG Heying1, XIANG Min2, HOU Jie1, FANG Ling1
    Journal of Vibration and Shock. 2024, 43(20): 238-246.
    Abstract ( 42 ) Download PDF ( 23 )   Knowledge map   Save
    The excellent drag reduction performance of the supercavitating shape of the vehicle is helpful to achieve a fast and accurate strike on the target underwater, and the good buffering and load reduction effect of the head jet load reduction method can greatly reduce the impact damage of the vehicle during the high-speed water entry process. Therefore, several models of head-jet supercavitating trans-media vehicle with both load reduction and drag reduction performance were designed, and the one-way jet and two-way jet modes were introduced. Based on the VOF multiphase flow model, the cavitation, load and resistance characteristics of the head jet supercavitation vehicle during the vertical water entry process were studied, and the influence of the jet volume on the water entry performance was analyzed. The results show that the design of the head jet combined with the supercavitation shape can reduce the navigation resistance of the vehicle after entering water, and the drag reduction effect of the two-way jet is better, because the two-way jet can generate a fully wrapped supercavitation that makes the whole process of the vehicle without wetting; the cavity air cushion formed by the head jet can not only significantly reduce the peak axial impact acceleration, but also delay the peak occurrence time, thereby reducing the impact load on the vehicle, and the two-way jet performance is also better in this regard; with the increase of the jet volume, the growth rate of the relative load reduction efficiency of the two-way jet is not good.
  • LI Wengheng, ZHU Changsheng
    Journal of Vibration and Shock. 2024, 43(20): 247-254.
    Abstract ( 23 ) Download PDF ( 26 )   Knowledge map   Save
    In order to realize the vibration estimation at unsensed positions in the rotor systems, this paper proposed a vibration displacement reconstruction method based on an unknown input observer. Firstly, the dynamics model of the rotor system is established by the finite element method, and the accuracy of the model is verified by modal test. Then, a design method to solve the problem of unsatisfied observer matching condition by constructing an unknown input observer with auxiliary output based on the second-order derivatives. The state observability of the rotor system is investigated. Finally, experiments are carried out on a lobule-cantilever low-pressure single-rotor system test setup. The experimental results show that under the condition that the mathematical model contains two orders of rigid and the first two orders of bending modes, the reconstruction errors of vibration peaks of the two orders of rigid modes at the target position are all no more than 25%.
  • LI Li1, 2, YAN Hubin3, HAN Yan3, WANG Wei3, LI Chunguang3, ZHOU Xuhui3
    Journal of Vibration and Shock. 2024, 43(20): 255-262.
    Abstract ( 28 ) Download PDF ( 33 )   Knowledge map   Save
    Based on the research background of the aerodynamic interference-induced aeroelastic instability of the hoisting cable, an aeroelastic model of the hoisting cable considering the sag effect and similar aerodynamic shape was designed and fabricated. Through the wind tunnel test, the influence of cable spacing on the vibration characteristics of the critical instability wind speed, vibration frequency and motion trajectory of the aerodynamic disturbance of the hoisting cable was analyzed, and the difference of aeroelastic instability caused by aerodynamic interference of the double cable system and the triple cable system was compared. The results show that when the two cables are arranged in series, the downstream cable is disturbed by the wake of the upstream cable, and the wake vibration is obvious, while the upstream cable is not obviously disturbed by the downstream cable, and the aerodynamic stability is good, and there is almost no vibration. When the three cables are arranged in series, not only the downstream cable is disturbed by the wake of the upstream cable and the air elastic instability, but the upstream cable is also vibrated by the aerodynamic interference of the downstream cable. There is a significant difference in the instability and vibration characteristics of the pneumatic bomb caused by the aerodynamic interference of the double cable and the triple cable.
  • WANG Yueyang1, 2, CHEN Shaolu2, 3, LONG Jingbing1, 2, WANG Jiawei1, 2, CHEN Yingyu1, 2
    Journal of Vibration and Shock. 2024, 43(20): 263-274.
    Abstract ( 30 ) Download PDF ( 27 )   Knowledge map   Save
    The impact force experienced by a vehicle entering water at high speed across media can threaten its structural safety and the stability of its entry trajectory. In order to explore the influence of water entry impact on the structure, the cylinder with foam head cap was taken as the experimental research object to explore the water entry impact load characteristics of different foam head caps under different water entry speeds and angles. In the experiment, high-speed camera technology was used to capture the shape characteristics of the water inlet bubbles of the cylinder with a leading cap, and the bubble features were analyzed based on the Canny edge detection algorithm; At the same time, the water impact load is obtained through the built-in accelerometer, and the CEEMD method is used for filtering load analysis. By analyzing the images and sensor measurement results of the experimental process, the evolution characteristics of bubbles and the variation rules of acceleration in water entering different speeds, angles, and head shaped cylinders were obtained, and the reasons for these changes were compared. The load reduction effects of different load reduction methods were also compared. The experimental results show that the load on the cylinder entering the water increases linearly with the square of the velocity; The head shape has the most obvious buffering effect on the low speed water entry load of the cylinder. The load reduction effect of the head cap with conical shape reaches 86.8%, and the load reduction and buffering effect of the conical foam head cap reaches 97%. In addition, the experiment also observed the phenomenon of the tail bubbles gradually falling off after the deep closure of the water entering bubbles of the cylinder, which formed a gradually decreasing pulse load on the cylinder; PMI foam head cap will not change the shape of water entering cavitation, but will make the cavitation wall rough and fuzzy.
  • U Taiying1, WEN Huabing1, PAN Fei1, GUO Junhua1, SHEN Hua2
    Journal of Vibration and Shock. 2024, 43(20): 275-281.
    Abstract ( 24 ) Download PDF ( 17 )   Knowledge map   Save
    The corrugated muffler can maximize the muffling in specific frequency bands, and the frequency bands are complemented by adjusting the recombination of different corrugation depths to obtain irregular corrugated structures. Calculate the transmission loss of single bellows by using the theoretical formula of side-branch resonance cavity, and measure the acoustic performance of bellows by constructing an experimental bench based on the double-loading principle, compare theoretical and experimental results with numerical predictions. The results showed that the corrugation depth is the main factor affecting the resonance frequency of single corrugated structures; Irregular corrugated structure transfer loss bandwidth is mainly affected by the number of irregular corrugations, the depth difference of adjacent corrugations; The volume of the anechoic chamber affects the effective bandwidth frequency range. The final optimized result improves the mean value of transmission loss by about 20.55 dB in 1000-5000 Hz and broadens the bandwidth by about 1750 Hz compared to the conventional bellows.
  • RAO Chenjie1, WANG Jingchun2, WANG Dapeng1, HOU Weihong2, NIU Xing1
    Journal of Vibration and Shock. 2024, 43(20): 282-288.
    Abstract ( 45 ) Download PDF ( 23 )   Knowledge map   Save
    In order to study the distribution and evolution law of vehicle-induced damage in horseshoe shaped tunnel of heavy haul railway, the plastic damage constitutive model of concrete and the tensile and compressive constitutive relationship of concrete recommended by the code were combined. Based on the improved Miner cumulative damage theory, a coupling dynamic model of horseshoe tunnel and surrounding rock for a single line of heavy-haul railway was established. The damage distribution characteristics, cumulative damage, incremental damage evolution and fatigue life prediction of tunnel lining structures under long-term action of heavy-haul trains were studied. The results show that the long-term vehicle-induced lining damage is mainly distributed in the invert of the track, the intersection of invert and side wall and the intersection of invert filling and side wall. The damage amount increased by 3.41 times compared with the maximum damage position with no load. Both cumulative damage and damage increment increase with the increase of operation times, and the change is non-linear. The fatigue life of the lining structure is 94.2 years, and the inspection and maintenance of the tunnel lining should be carried out when the train runs for 68.5 years and the damage increment enters the significant growth area.
  • YANG Wenchao1, YANG Tingfang1, SU Sheng1, XIE Zelong1, HE Bin1, YI Wei2
    Journal of Vibration and Shock. 2024, 43(20): 289-297.
    Abstract ( 64 ) Download PDF ( 31 )   Knowledge map   Save
    In order to solve the problems of narrow sound insulation band in low frequency range, poor durability and weak risk resistance of membrane-type acoustic metamaterial (MAM), and to explore the application of MAM in the transformer noise reduction field, a noise reduction structure coupled with pyramid sandwich panel and MAM is designed. By the finite element method, the sound insulation performance of the coupled structure and its acoustic and vibration characteristics are studied, the sound solid coupling model of the structure is established, the sound transmission loss and vibration mode of the structure are analyzed, and the factors affecting the noise reduction of the structure are explored. The results show that the coupling structure has excellent broadband sound insulation characteristics in low and medium frequency, and the sound insulation characteristics of the structure can be changed by adjusting the parameters of the membrane and the plate. The sound insulation of the optimized structure at the main noise frequency of the 110kV transformer can exceed that of 110dB.
  • WANG Yifan, HE Xiping
    Journal of Vibration and Shock. 2024, 43(20): 289-304.
    Abstract ( 0 ) Download PDF ( 7 )   Knowledge map   Save
    A window structure (double rare earth rods structure) giant magnetostrictive transducer is developed. The transducer was designed by the equivalent circuit method. In order to get the maximum amplitude of the vibration output end, the uniformity of the magnetic field in the rare earth rod and the small peak stress rare earth rods, the structure size of the transducer was optimized by the finite element method. The impedance circle and the amplitude of the output end of the transducer were simulated and calculated with the increase of the excitation current, and the relationship between the temperature rise and time at the operating frequency was also calculated. The test results of the fabricated transducer show that the measured value is 19.64 kHz, the design frequency is 19.45 kHz; the experimental test displacement amplitude is 6.1 m at 1A excitation current, and the calculated value is 6.3 m; the tested value of electro-acoustic efficiency is 52.58%, and the calculated value is 41.51%. After 15 minutes of transducer operation under 1A excitation current, the temperature rises to 45.5 °C by tested, while the simulation calculation temperature rise is 47.8°C. The experimental tested is in good agreement with the theoretical simulation calculated.
  • WEI Wei, LI Baozuo, YU Songjian
    Journal of Vibration and Shock. 2024, 43(20): 305-317.
    Abstract ( 56 ) Download PDF ( 20 )   Knowledge map   Save
    In order to compensate for the lack of active control force in the passive suspension of automobiles, a linear motor type active suspension based on the traditional passive suspension structure was designed. Adding linear motors to the passive suspension can increase the damping force of the active suspension and reduce the vibration of the vehicle. Firstly, the structure of the linear motor was designed. Secondly, Ansys/Maxwell magnetic field analysis software and control variable method were used to optimize the structural dimension parameters of each part of the linear motor. The results showed that the fluctuation of electromagnetic thrust of the linear motor was reduced by 83%, while the steady thrust was increased by 10%. Finally, the simulation model of linear motor active suspension is built in Matlab/Simulink, and fuzzy PID is used to control the linear motor active suspension system. The analysis is carried out in time domain and frequency domain respectively. The results show that: Compared with the passive suspension, the body acceleration, suspension dynamic deflection and tire dynamic load of the linear motor active suspension are effectively inhibited, and the power spectral density of the body acceleration is also greatly reduced, which effectively improves the ride comfort and handling stability of the vehicle.
  • SUN Zhaolin, YANG Lu, MA Yuefei, LIU Meiyu
    Journal of Vibration and Shock. 2024, 43(20): 318-324.
    Abstract ( 36 ) Download PDF ( 15 )   Knowledge map   Save
    A nondestructive testing method combining ground-penetrating radar (GPR) and phased-array ultrasonic testing (PAUT) was proposed to address the difficulty of detecting defects on the bonding surface of concrete composite slabs. In order to verify the validity of the method, and to study the influence of reinforcement on the detection method, a single-layer reinforced composite slab and a double-layer reinforced truss composite slab were designed and fabricated. On the bonding surface, three types of artificial defects were set: delamination, voids and debris. The detection results showed that the method can effectively detect all defect types with accurate defect localization. The relative errors of detecting the size of defects were below 20%, and the average errors of detecting two specimens were 8% and 6.6%, respectively; the relative errors of detecting the depth of defects were below 10%, and the average errors of detecting two specimens were 4.3% and 4.8%, respectively. This method is an effective and accurate method for detecting defects in the bond surface of concrete composite slabs.
  • YUE Maoling1, YU Zexing1, 2, SUN Jiaying1, XU Chao1, 3
    Journal of Vibration and Shock. 2024, 43(20): 325-333.
    Abstract ( 60 ) Download PDF ( )   Knowledge map   Save
    In aerospace engineering, there are a large number of structures with curved edges or curved surfaces, and when elastic waves are used to detect the damage of such structures, the analysis of elastic wave propagation behavior in the structure is an important link, and at present, numerical simulation is an effective method to study the propagation behavior of elastic waves in structures. The existing numerical simulation methods mostly use straight-edge elements when modeling curved-edge structures, and there are large geometric approximation errors at the structural boundaries, which affects the accuracy of elastic wave propagation simulation. To solve this problem, under the time-domain spectral element methodology, a sub-parametric curved-edge spectral element with 27 nodes is derived in this paper, which uses a quadratic interpolation function to describe the element boundary. This element can accurately describe the geometric characteristics of complex curved-edge structures, so it is suitable for simulating the propagation behavior of elastic waves in such structures. Taking the wave propagation problem in thin-walled cylindrical structure as an example, the propagation behavior of elastic waves in this structure is calculated by using the curved-edge spectral element method, straight-edge spectral element method and classical finite element method respectively to verify the efficiency and accuracy of the proposed method. The results show that under the same calculation accuracy, the calculation scale of the curved-edge element method is much smaller than that of the classical finite element method, which verifies the efficiency of the curved-edge element method. Under the same mesh scale, compared with the straight-edge spectral element method, the calculation model of the curved-edge spectral element method can better approximate the actual structure, so as to achieve higher solution accuracy, and the curved edge spectral element method is not sensitive to the change of element size, and can quickly converge to an accurate solution at a smaller mesh scale. In addition, the larger the curvature of the structure, the more significant the computation advantages of the curved-edge element method compared with the straight-edge spectral element method.
  • WANG Dongxian, ZHAO Jianlei, ZHAO Weijia, ZHU Rui
    Journal of Vibration and Shock. 2024, 43(20): 334-342.
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    Spacecraft actuators like Control Moment Gyroscopes (CMGs) can generate micro-vibrations, which directly affect the imaging quality of the space optical instruments and even the lifespan of key components of the spacecraft. Eventually, the key performance of the spacecraft can be affected. Although the integrated metastructure exhibits excellent vibration isolation ability, the manufacturing uncertainty on the complex geometry can affect the overall vibration isolation performance. In this paper, an efficient uncertainty analysis method based on global sensitivity is proposed, which can accurately quantify the vibration isolation performance deviation caused by the manufacturing uncertainty. First, an efficient global sensitivity analysis method is proposed by combining high-order sparse point interval Chebyshev polynomial expansion (HOSPSCPE) with variance based Sobol's sensitivity index. Comparing with the traditional Monte Carlo (MCM) sensitivity analysis methods, this method improves computational efficiency by three orders of magnitude. Second, by ignoring the interval variables with smaller global sensitivity indices, the efficiency of the uncertainty analysis for complex metastructures can be further enhanced. Finally, experimental validations are carrying out. The results indicate that our proposed uncertainty analysis method based on global sensitivity can provide useful and efficient guidance for the design and manufacturing of vibration-isolating metastructures.