15 January 2024, Volume 43 Issue 1
    

  • Select all
    |
  • WANG Xiaodong1, ZHANG Haochun1, ZHAO Guiqi1, JI Hongli2
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 1-8.
    Abstract ( 394 ) Download PDF ( 205 )   Knowledge map   Save
    In the missile system, the vibration and impact produced by the engine and pyrotechnics will seriously affect the accuracy and reliability of the warhead, so it is significant to take effective measures to reduce the vibration and isolate the impact. Acoustic black hole (ABH) effect allows altering the phase velocity and group velocity of the wave propagation in a structure by changing the impedance. As a result, the wave is concentrated in the local area of the structure, and energy is efficiently dissipated by a little damping. The ABH with the advantages of high efficiency, light weight, wide frequency, which provides a new idea for structural dynamics control, and has the strong potential and application prospects. In this paper, with the aim of vibration suppression and shock isolation in multistage missile, a kind of structural design schemes (ABH ring) based on the ABH effect are presented to ensure the accuracy and reliability. The dynamics characteristics of ABH ring are analyzed by using the finite element method. It can be seen that the ABH ring has good characteristics about transfer and consumption of energy. The simulation model of ABH ring-warhead is established. By simulating the impact of random vibration and stage separation during flight, the system response characteristics are analyzed and suppression effect is evaluated. The results show that the proposed ABH ring has a good effect of vibration suppression and shock isolation under complex dynamic load: reducing the amplitude and increasing the attenuation rate. This research not only provides ideas for missile vibration reduction and shock isolation, but also effectively broadens the application of ABH new technology.
  • LIU Huan1,2,3, FAN Xiaoyi2,4, JIANG Yuanjun5, LIU Haonan2, HAN Peifeng6, TIAN Shujun6, LIU Junxin6
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 9-19.
    Abstract ( 218 ) Download PDF ( 193 )   Knowledge map   Save
    Based on the SPH-FEM coupled numerical method, this paper studies the dynamic response and failure mechanism of frame structure buildings under the impact of large rock debris flow from the aspects of structural failure form, impact time history, displacement and velocity of key points, and system energy. The calculation results show that the SPH-FEM coupled numerical method can well simulate the impact climbing, diffusion around flow and stable sedimentation of debris flow. Three intensity levels of debris flow are considered. In the case of low and medium intensity impact, the filling wall of the frame house is damaged and the whole structure of the house remains stable. In the case of high intensity impact, the gradual collapse of the frame building can be observed, and the failure mode of the frame column reflects the shear failure or plastic hinge failure mechanism. For the building structure, the impact damage ability of debris flow mainly comes from the impact force of the dragon head. The impact force of the dragon body decreases about 34.2% relative to the dragon head. The concentrated effect of large stones is the main reason for the local damage of the structure column. The energy of the system is mainly converted into internal energy (17.8%) and friction energy (82.8%) through kinetic energy of debris flow.
  • ZHANG Longwei1,2, YUAN Luqi1, CHEN Ning1, YUAN Shuaihua1, ZHANG Long1
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 20-27.
    Abstract ( 167 ) Download PDF ( 121 )   Knowledge map   Save
    The bridge weigh-in-motion (BWIM) can find axle weights from the measured response of the bridge acting by passing vehicles. However, since the measured response contains measurement errors, the accuracy of the traditional BWIM algorithm is reduced to a certain extent. To solve this problem, this paper proposes a novel BWIM algorithm based on Bayesian posterior estimation. The proposed algorithm considers the negative influence of measurement error on axle weight identification. Firstly, assume measurement error and axle weights both follow Gaussian distribution; Then, use the standard deviation of measurement error and axle weight standard deviation to obtain constraint factor which can restrain measurement error; Finally, the new solution equation of BWIM can be derived. In this paper, Bayesian algorithm is validated by numerical vehicle-bridge interaction model and in-situ test. The accuracy of Bayesian algorithm is compared to the results by the traditional BWIM algorithm. Results show that Bayesian algorithm can effectively suppress the effect of measurement error and improve the axle weight identification accuracy significantly.
  • BAI Xiaotian, YANG Wuzhe, WANG Zinan, ZHENG Hao
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 28-35.
    Abstract ( 194 ) Download PDF ( 107 )   Knowledge map   Save
    The fit clearance between the ceramic bearing outer ring and the bearing pedestal changes greatly in wide temperature ranges, and the shaft deflection caused by the rotor mass makes significant impacts on the motion of the shaft, especially when the shaft is long and slender. Then the load boundary conditions between the shaft and the bearing changes obviously, which has great influence on the bearing running performance. In this paper, a dynamic model considering the influence of deflection on the bearing rotor system in a wide temperature range is proposed, in which the thermal deformations of the pedestal and bearing are calculated separately as geometric boundary conditions. The shaft deflection is then considered to determine the contact forces between the inner ring and the shaft, and the dynamic characteristics of the ceramic bearing rotor system is thereby obtained. Parametric studies are carried out on the vibration situations of the full ceramic ball bearing considering the impacts brought by working temperature and shaft deflection, and the results are verified through experimental investigations. Results show that the shaft deflection leads to reductions in positive amplitudes of full ceramic ball bearing in wide temperature ranges, which results in unstable running of the system. The research results provide references for the dynamic analysis of full ceramic ball bearing, and also lay theoretical foundations for the improvement of the ceramic bearing rotor system stability.
  • HE Feifan, DU Jingtao, ZHAO Yuhao, LIU Yang
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 36-45.
    Abstract ( 144 ) Download PDF ( 122 )   Knowledge map   Save
    Analytical model of the transverse vibration characteristics of Rayleigh spinning beam with elastic boundary constraints including unbalanced concentrated mass and axial load is established by using the improved Fourier series method. Firstly, the kinetic energy and potential energy matrix equations of the spinning shaft-support system are listed. Secondly, the motion equations of the spinning shaft system are derived by Lagrange’s equation. Finally, Improved the Fourier series are used as the assumed form of the equations to calculate and solve. The influence of supporting translational stiffness, rotational stiffness and axial load on the critical rotational speed of the spinning shaft is studied. The influence of unbalanced lumped mass in the spinning shaft on the whirl frequency and critical rotational speed of the spinning shaft is analyzed. The characteristics of the amplitude-frequency characteristic curve of the spinning shaft as a function of the unbalanced lumped mass, the axial position and the supporting stiffness at both ends of the spinning shaft were investigated.
  • MA Shixin1, XIE Xingbo2, LI Xiangdong1, ZHONG Mingshou2, JI Yangziyi1
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 46-53.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To study the vulnerability of concrete obstacles subjected to shaped charge penetrator hits, the vulnerability of concrete obstacles hit by jetting projectile charge (JPC) and explosively formed penetrator (EFP) was evaluated through experimental and numerical studies. The results show that a suborbicular or approximative notched oval-shaped damage zone is generated when the top or side face of the obstacle is hit. The severity of damage increases as the hit location moves closer to the center of the damage zone. When the penetrators hit the top face vertically, the center of the damage area coincides with the center of the top. When the side face is hit horizontally, the center of the damage area coincides with the geometric center of the side. When the penetrators hit obliquely upward, the center of the damage zone generated by JPC and EFP moves down by about 27.8 cm and 28.2 cm, respectively, whereas it moves up by about 26.5 cm and 28.7 cm when the penetrator hits the side obliquely downward. The concrete obstacle tends to be severely damaged when the penetrators hit the side horizontally. Furthermore, JPC demonstrates higher damage capability on the concrete obstacles than EFP with the same caliber charge under the same hit conditions.
  • XIONG Zhongming1,2, CHEN Zhi1, CHEN Xuan1,2, ZHENG Kun1, A Xin3,4
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 54-63.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The earthquake damage characteristics of the shallow buried subway station crossing the ground fissure (SSGF) were explored through the shaking table test. Then, considering the nonuniformity of the dynamic response of the ground fissure site, a pushover analysis method for the SSGF was used to study the earthquake damage mode of the SSGF. The results show that the pushover method can realistically simulate the activity of the ground fissure site and the damage characteristics of the SSGF in the earthquake. Under the horizontal seismic action, the mutual compression and separation activity mainly occurs in the hanging wall and foot wall, in which the mutual compression will exert the compression-bending effect on the central columns of the SSGF. The horizontal shear deformation of the soil is the main external factor of structural damage, and the additional compression-bending effect will further increase the axial compression ratio of the central column, reduce its deformation capacity, and accelerate the seismic damage of the SSGF. Under the unique deformation of the ground fissure site, the horizontal shear deformation capacity of the columns in the bottom of the SSGF is relatively weak, and the shear force of the structural members shows an obvious spatial distribution pattern. Therefore, the central column at the bottom of the SSGF in the hanging wall is the key seismic member of the SSGF. The research results have important references for the seismic design of these structures.
  • LAN Shuwei1, ZHOU Donghua2, CHEN Xu1, MAO Dejun1
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 64-70.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The support between the steel frame and shear-type bracing, the mutual support between the same layer columns and the inter-story interaction should be considered for overall stability calculation of multi-story shear type braced steel frames. The effective length coefficient method in the specification cannot consider these factors, which may lead to unreasonable design. An analytical algorithm for calculating the overall stability of multi-story shear type braced steel frames. Firstly, the relationship between the brace stiffness and the critical bearing capacity of the structure is analyzed, and the formula for calculating the floor critical braced stiffness is derived; Then, the formula for calculating the critical stiffness ratio coefficient of frame columns under arbitrary supports is derived by using the spring- rocking column mechanical model; Then, the effective lateral stiffness and load stiffness of each floor are assembled between floors, and the solution of the critical bearing capacity of multi-story shear type braced steel frames is converted into the solution of the floor effective lateral stiffness; Finally, based on the weighted average method of axial force, the calculation formula for calculating the critical bearing capacity of the multi-story shear braced steel frame is derived, which can judge the weak story of the structure, quantitatively calculate the mutual support between floors, and effectively make up for the deficiency that the specification cannot solve the effective length coefficient of the columns of the weakly braced steel frame.
  • CUI Shuangshuang1,2, MENG Yao2, CHEN Weihong3, SUN Hao2
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 71-82.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The use of ECC instead of concrete can improve the progressive collapse resistance of structures under accidental loads but bond-slip may occur between reinforcement and ECC during the stage of large deformation of the catenary. In this paper, based on the Hopkinson Pressure Bar (SHPB) test device, dynamic bond-slip behavior of steel bar and ECC is tested. The influence of strength grade, strain rate and diameter of steel bar on ultimate bond strength, stiffness and slip are analyzed. Mean bond-slip curves of steel bar and ECC under high strain rate are obtained. The dynamic increase factor DIF is calculated by comparing dynamic bond-slip curves with static bond-slip curves. Further, the distribution of bond stress and relative slip at different anchorage positions are obtained by placing strain gauge in the slot of reinforcement, and the bond position function is proposed. Finally, according to the test results, the average bond slip constitutive force of rebar and ECC is obtained, and then the dynamic bond-slip constitutive force considering the influence of anchorage position is obtained by multiplying the bond position function, which provides experimental basis and theoretical reference for ECC structural member design and finite element analysis.
  • FENG Zhipeng, ZANG Fenggang, LIU Shuai, HUANG Xuan, QI Huanhuan
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 83-90.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Although the harmfulness and importance of fluidelastic instability of the tube bundle have attracted Particular emphasis again since the SONGS accident in 2012, the fundamental factors leading to this instability have not been determined. In order to further study the basic physical mechanism of fluidelastic instability, taking the parallel triangular tube bundle commonly used in PWR steam generator as the object, based on the open source CFD tool OpenFOAM and coupling the dynamic equation of the tube, this paper solves the unsteady Navier-Stokes (uRANS) equation with moving boundary, establishes a numerical model to study the damping-control instability mechanism, and then predicts the fluid-structure interaction of the tube bundle. The key parameters and flow response affecting the damping-controlled instability mechanism are revealed. The response characteristics, energy input and dissipation, coherence, phase difference and correlation coefficient between lift and displacement, spectral characteristics of lift and dominant excitation mechanism are discussed under different mass damping parameters. It further reveals the dominant excitation mechanism and key flow phenomena in the fluidelastic instability of tube bundle, which is helpful to understand the interaction mechanism between the tube bundle and the fluid, and provides a reference for using the open source CFD tool OpenFOAM to predict the instability behavior of the fluidelastic instability in engineering.
  • WU Di1, XIE Xiling2, ZHANG Zhiyi1,2
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 91-98.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    An approach is proposed to search the minimum number of actuators for an active vibration isolation platform-cabin shell system. Based on the established dynamic model of the multi-channel active vibration isolation system, the optimal allocation of actuators in this approach is described as a 0-1 nonlinear programming problem, in which the active/silent state of the actuators are independent variables and the objective function is constructed from the system responses. The teaching-learning based optimization algorithm (TLBO) is used to find the optimal actuator allocation. The optimization is carried out to verify the effectiveness of the proposed method, and the numerical results show that the vibration and acoustic radiation of the shell can be suppressed by part of the actuators in a specific excitation.
  • ZHANG Xiao, CUI Jie, LI Mingyuan, QIN Zikai
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 99-106.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to study the damage or even fracture of ship hull caused by bubble secondary shock wave, the interaction mechanism between bubble and damaged boundary is studied. The damaged bulkhead is simplified as an elastic wall with a circular break. The bubble dynamics model of underwater explosion near the damaged boundary is established based on CEL method. The numerical results are compared with the model experimental results, which verify the effectiveness of the method established in this paper. On this basis, the effects of bubble jet, bubble volume, pulsating period and bubble on wall impact damage are studied, and the pulsating laws of bubbles under different break parameters and the characteristic laws of jet penetration, tear, etc. are proved. It provides theoretical and technical support for the research and development of high-energy weapons and the safety protection of damaged ships.
  • LI Dan1,2, SHEN Peng1, HE Wenyu1, XIANG Shulin3
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 107-115.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In view of the difficulty in accurate detection of fatigue damages in bridge steel trusses, this study proposes a method to identify the damage degree of welded truss joints based on time-frequency analysis and deep learning of acoustic emission signals. The acoustic emission signals generated by the truss joints during operation are firstly analyzed by wavelet transform to characterize their energy distribution patterns in the time-frequency domain for different damage degrees. After that, a convolutional neural network (CNN) model is established to extract damage features from the time-frequency diagrams. The training efficiency and learning ability of the model are improved through transfer learning. Accurate identification of severe damage, minor damage, and intact cases of the truss joints can then be realized. Further, the activation areas in each convolution layer of the model are visualized to reveal the damage feature learning process and classification logic. Filed test was carried out on the central longitudinal steel truss web of a suspension bridge. The results showed that compared with the one-dimensional CNN model using time-domain waveforms of acoustic emission signals for feature learning, the two-dimensional CNN, taking time-frequency diagrams that contained more abundant damage information as the input, achieved an accuracy of more than 94% in identifying the three damage degrees of the truss joints. It behaved with higher robustness and potential for practical applications.
  • YAO Runhui, ZHOU Jin, DING Song, ZHANG Yue, XU Yuanping
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 116-122.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The magnetic levitation molecular pump has the characteristics of high working speed and large rotor pole rotational inertia. A new control method based on filtered cross-feedback and notch filter is proposed for the bending mode vibration and cone-motion mode vibration of the large inertia rotor of the magnetic levitation molecular pump during the speed-up process.The mathematical model of the magnetic bearing and the large inertia rigid rotor system is established, and the frequency of cone-motion mode vibration of the rotor is obtained. According to the model, the suppression effect of the filtered cross-feedback controller on the cone-motion mode vibration is analyzed, and a notch filter is designed to suppress the bending modal vibration of the rotor at different speeds. The experimental results show that the magnetic levitation molecular pump is stably increased to the working speed of 18000rpm, the vibration displacement of rotor is 35μm, and the bending mode vibration and the cone-motion mode vibration are effectively suppressed.
  • LI Meng1,2, GUO Huiyong1,2
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 123-130.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Damage detection technique plays a fundamental role in the Structural Health Monitoring (SHM) system. To further improve the accuracy and applicability of damage identification, a new method is proposed, which integrates J-divergence distance function and Vector Autoregressive Moving Average (ARMAV) model. First, pre-whitening filter was used to cancel the correlation of excitations and de-noise the acceleration time series. Then, a ARMAV model was established, whose autoregressive parameters and residual variance were used to develop a damage indicator for damage identification. Finally, to verify the effectiveness of this method, standard data sets of laboratory three-story frame was used, and the damage identification experimental study on the relay tower model was carried out. The results show that the damage identification method based on ARMAV model and J- divergence distance is easy to operate, and can accurately and efficiently localize the damage of the frame and relay tower structure. Furthermore, the proposed method is less affected by environmental changes, and is promising to be used in online structural health monitoring systems.
  • LI Xiaoxiong1, ZHUANG Haiyang1,2, WANG Wei1, ZHAO Kai1, CHEN Guoxing1
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 131-137.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To clarify the seismic performance of the cross-river and cross-sea shield tunnel structure in the liquefied flow slippage area of the site, a 4.8km refined beam-spring shield tunnel model is established based on the generalized response displacement method. The displacement time histories of soil layers under different ground motion intensities in a slightly inclined liquefiable wide river valley site are used as input ground motion states. This paper investigates the effects of site liquefaction flow slippage on the longitudinal seismic response of shield tunnels and the longitudinal opening of adjacent pipe rings. According to the results, the liquefied flow slippage of the site will cause the shield tunnels to produce extremely large longitudinal openings, abrupt changes in section tension and compressive. It fully illustrates the hazard of site flow slippage on the seismic safety of tunnel structures. The severe damage locations of the shield tunnel are located on the sliding surface of the liquefied soil layer. The bending moment variation curves and the acceleration amplification coefficient curves along the axis are consistent with the river valley topography, and the curves show obvious abrupt changes in the liquefaction zone.
  • ZHU He1, LIAO Hanliang1, ZHANG Renqi2, LIU Cheng1
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 138-144.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    For the study of transmission line conductor dc asymmetric operation characteristic of melting ice, with transmission conductor LGJ - 400/50 as the research object, and establish a transmission wire entity model under different operating conditions, using COMSOL software to explore the influence of different ice thickness on the conductor temperature distribution, and the different environment temperature and different wind speed on the center conductor temperature change is analyzed, The wire temperature at the deicing time was applied as the initial condition, and ANSYS LS-DYNA PrepPost nonlinear structural dynamics model was used to establish the finite element model of three-phase wire-phase interval wire system in the actual operation process, and analyze the dynamic response of asymmetric deicing in DC melting of the wire system. The results show that the maximum deicing jump height of the wire system varies with the number of deicing phases under the conditions of different deicing schemes. The deicing situation of the three-phase wier-phase interval wire system is asymmetric compared with that of the single wire in the process of deicing. According to the influence rule of spacer rod arrangement on the dynamic response of the wire system, The phase spacing of conductor can be optimized to ensure the safe operation of DC melting process.
  • PAN Xuejiao1, DONG Shaojiang2, ZHU Peng3, ZHOU Cunfang2, SONG Kai4
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 145-152.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the problem of the difference in characteristic distribution of the collected data of rolling bearing life status under variable working conditions and the poor generalization ability of the deep neural network model, an end-to-end transfer prediction method of rolling bearing remaining life (RUL) is proposed in this paper, combining the temporal convolutional neural network (TCN) and the residual self-attention mechanism (RSAM). Firstly, the one-dimensional time-domain signal collected by the sensor was converted into a frequency-domain signal by short-time Fourier transform; Secondly, the proposed network was used in the general feature extraction layer of the transfer residual life prediction network. While extracting time series information, the RSAM was further used to capture the local degradation features of the bearing, which enhances the model's ability to extract transfer features; Thirdly, the proposed joint domain self-adaptive strategy is used to match the characteristic distribution difference of rolling bearing life state data under variable working conditions, so as to realize the migration prediction of bearing life state information under different working conditions; Finally, the experimental verification was carried out on the full life of the rolling bearing. The results show that the proposed method can effectively realize the RUL prediction of the rolling bearing under variable working conditions, and obtain a better prediction. performance.
  • ZOU Xiaoguang1, YANG Weiguo1, WANG Meng1, LIU Pei1, GE Jiaqi2
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 153-164.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Earthquake damage research showed that the freestanding museum collections housed in the museum were easily damaged when earthquakes occurred. While museum staff often rely on their own experience to secure the museum collections with fasteners to protect them from being damaged in the earthquakes, but there is a lack of scientific methods to evaluate the effectiveness and seismic performance of fasteners. In order to reasonably evaluate the seismic performance of fasteners, aiming at the seismic damage mode of museum collections, this paper put forward an analysis method of seismic fragility for museum collections based on logical regression, which takes the rocking angle and contact stress as the discriminant indexes. Finally, a method to evaluate the seismic performance of fasteners by calculating the seismic risk of museum collections through risk convolution is proposed. In this paper, the finite element analysis was carried out to further explain and verify the proposed evaluation method, and the proposed method was used to evaluate the seismic performance of the fasteners adopted for a precious museum object exhibited in a museum in North China. The results show that the evaluation method based on probability risk analysis proposed in this paper can quantify the seismic performance of fasteners for securing museum collections, and provide a scientific basis for the selection of fasteners. The evaluation process and results of the case study can provide effective reference for museum collections.
  • YANG Ying1, JIN Licheng2, XIANG Yiqiang2, HE Yuliang1
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 165-171.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to reduce the dynamic response of submerged floating tunnel (SFT) under moving load, tuned mass damper (TMD) was used as the vibration control measure, and the vibration reduction effect was analyzed. The SFT tube was simplified as a beam on elastic foundation, the vehicle load was simulated by a moving harmonic force, the added mass force and the hydraulic resistance which caused by the movement of the tube were considered according to the Morison equation, the vibration governing equations of the SFT tube-TMD system were established. The equations were solved by the Newmark-β method, and the vibration reduction effect of TMD on the SFT tube was analyzed. In view of the vibration characteristics of the SFT tube, a distributed TMD layout was proposed, and the influence of moving speed and TMD damping ratio was discussed. The results shows that TMD has a significant vibration reduction effect on the SFT tube under moving harmonic load, and the maximum displacement vibration reduction rate is more than 50%. Since multiple modes participate in vibration, the effective damping range of a single TMD is limited. Under the condition of keeping the total mass unchanged, the distributed TMD can achieve better overall vibration reduction effect. Increasing the mass ratio of TMD and decreasing the moving load speed are helpful to improve the vibration reduction effect of TMD. Increasing the damping ratio will weaken the effect of TMD, which should be determined by considering the damping effect and the requirements of the working space.
  • CAO Lihua, XUE Chuan, SI Heyong, GAO Lulu, LI Xiang, HAO Decheng
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 172-183.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    With an aim to accurately reflect the motion characteristics of the steam turbine rotor-bearing-seal system under steam exciting force, the differential equation of rotor motion including nonlinear dynamic characteristic (nonlinear stiffness, damping) is derived. The simulative equation of nonlinear steam flow excitation force obtained by numerical simulation is coupled to the equation of motion, and the corresponding equation of motion is solved by Runge-Kutta method. The necessity of investigating nonlinear factors and the accuracy of motion differential equation are verified based on experimental comparison. On this basis, the influence of different nonlinear dynamic characteristic coefficients on the motion characteristics and stability of the rotor under the steam flow excitation force is analyzed. It is shown from the result that the nonlinear dynamic characteristic in the system will change the different types of chaotic motion regions and the displacement of the rotors, making the occurrence range and amplitude of the power frequency of 1/2, 1/3, and 2/3 change, and the dense frequency phenomenon increase. The rotor displacement in the high load area decreases after coupled thermal and dynamic loads. Compared with the Lyapunov exponent, the mean value increases after considering nonlinear dynamic characteristic; reasonable nonlinear stiffness can improve the stability of the system, and high nonlinear damping can improve the stability of the system; the system with coupled thermal and dynamic loads is more stable during operation under high load.
  • TONG Xiaoling, ZENG Feiyu, JIANG Ke, LIANG Lei
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 184-192.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Fiber optic distributed acoustic sensing (DAS) systems are widely used in the fields of microseismic monitoring and source localization because of their high sensitivity, resistance to electromagnetic interference and distributed long-distance sensing. In this paper, the vibration signal generated by the explosion is collected by the DAS system and the arrival information of the signal is used to locate the explosion source. However, due to the noise interference at the explosion test site, the signal and noise are mixed, and the arrival time information obtained by the arrival time algorithm has a large error, which affects the positioning accuracy, so the signal needs to be denoised. In view of the serious loss of effective information when empirical mode decomposition methods are used for explosion vibration signals, a fusion noise reduction method based on complementary ensemble empirical modal decomposition (CEEMD), multiscale permutation entropy (MPE), and improved wavelet threshold denoising (WTD) is proposed to denoise the signals collected by a distributed acoustic sensing system. It was compared with the EEMD-MPE, CEEMD-MPE, and CEEMD-MPE-WTD methods. The experimental results show that this method can improve the signal-to-noise ratio to 25.95 dB, which is significantly higher than that of the other methods. The denoised signal was used to locate the source, and the error was within 5 m. This method can remove the environmental noise and high-frequency noise of the instrument, while retaining the dominant frequency energy of the explosion vibration signal. The results show that this method is suitable for denoising explosion vibration signals.
  • LU Naiwei1,2, LIU Jing1, WANG Kai3, WANG Honghao1
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 193-201.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The transverse distribution of wheel tracks is a key factor to generate random stress spectrum at welded joints of orthotropic steel bridge deck. In addition, the morphology of welding defect are random in nature. Thus, the random propagation behavior of fatigue cracks in steel bridge deck was induced. In order to study the random propagation characteristics of fatigue cracks at the welded joints of steel bridge deck, the effect of wheel tracks transverse distribution on equivalent stress intensity factor of welded root and toe of orthotropic steel bridge deck were analyzed based on the fracture mechanics theory and extended finite element method. The effect of wheel tracks transverse dispersion, initial crack depth and initial crack morphology ratio on distribution of random propagation path of fatigue cracks at welded joints were revealed. The results indicate that transverse distribution of vehicle wheel tracks has a significant effect on the stress intensity factor of the fatigue cracks of the welded root and the welded toe. The maximum equivalent stress intensity factor of welded root is 85.99(MPa•mm1/2), which was 6.72% higher than that of welded toe. The dispersion degree of transverse distribution of wheel tracks and initial crack depth are positively correlated with the dispersion of random propagation path distribution of fatigue cracks of welded joints of orthotropic steel bridge deck, and the initial crack morphology ratio is negatively correlated with them.
  • SHAO Shiru, WANG Yang, SUN Shuangshuang
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 202-211.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on the mesomechanics of composite materials, the damping prediction model of glass/carbon fiber hybrid composite laminated beams in hygrothermal environment was established by using the principle of energy dissipation and macroscopic strain energy method. The MATLAB calculation program for the loss factor of glass/carbon fiber hybrid composites under hygrothermal environment was written, and the influence of fiber laying angle, volume fraction, laying order and hygrothermal effect on the damping performance of glass/carbon fiber hybrid composite laminated beams was studied. The results showed that: hygrothermal strain is the main mechanism affecting damping characteristics; the loss factors of glass/carbon fiber hybrid composite laminated beams increase with the increasing of temperature and water absorption concentration, and the influence of temperature is much greater than water absorption concentration; the higher the fiber volume fraction, the greater the degree of influence by moisture and heat; the influence of ply angle on the loss factor is much higher than that of moisture and heat, ply mode, and fiber volume fraction.
  • YAN Jun1,2, ZHANG Chenguang1, SAI Yinfu1, WANG Fuhao1, HUO Sixu1, CHAI Xianghai3,4, YAN Kun5
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 212-217.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Hollow sandwich blades are widely used in aero-engine design because of both lightweight and energy-absorbing properties. In this paper, the effect of four different lattice configurations on the bird strike resistance of the equivalent simulated parts of the infilled blade is investigated. The equivalent stiffness of the four lattice configurations is given by homogenization method. Then the lattice-filled curved plate model is established based on the modeling method of shape-following adaptive lattice-filled structure, and the lattice-filled curved plate structure is manufactured by 3D printing for bird strike tests and numerical simulations. Finally, the bird strike resistance of four different lattice-filled curved plate was analyzed from the viewpoint of deformation and energy absorption, and BCC has better resistance to both deformation in z-direction and in-plane y-direction creases and better energy absorption than other types of structures. Therefore, BCC has better bird strike resistance.
  • ZHANG Xianwen, LI Guozheng, WANG Weijie, SU Shuqiang
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 218-229.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the problems of low output power and small working frequency range of existing vibration energy harvesters, a new structure of nonlinear maglev vibration energy harvester based on magnetic liquid was proposed. Firstly, the structure of the new energy harvester is proposed, its working principle is analyzed, and the nonlinear mechanical model of magnetic dipole is established. The simulation results are compared with the experimental data to verify its accuracy. Then, the second-order buoyancy and viscous damping of the magnetic liquid were analyzed, and its mathematical model was established. The approximate solution of the dynamic equation of the energy regenerator was solved by multi-scale transformation method, and the output performance response model was obtained. Finally, the influence of three kinds of system structure parameters and excitation acceleration on the output performance of energy harvester is analyzed and the output performance of energy harvester with or without magnetic liquid is compared. The results show that the distance between magnets, the total mass of the suspension magnet and the magnetic liquid and the excitation acceleration can effectively change the working frequency range and the output power amplitude of the energy harvesting device, and the damping ratio mainly affects the output power amplitude. The output voltage peak value and output power peak value of the new energy harvester respectively reach 426.88mV and 0.56mW. The output voltage and power respectively increase by 22.67% and 75% after adding magnetic liquid. Compared with other low-frequency vibration energy harvesters, it has better output power characteristics. The structure and dynamic model of the new maglev energy harvester can provide a new solution for broadening the range of the working frequency band and enhancing the output power performance of this kind of energy harvester, which has good reference value.
  • SUN Wenjing1, WANG Jiahao1, THOMPSON David2, WANG Tengfei1, ZHOU Jinsong1
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 230-236.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Fatigue failure of metal coil springs in the suspension system of railway vehicle during service can affect the safety of train operation. In response to a fatigue failure in a certain series of coil springs, an accurate model for extracting the spring load is established, taking into account the coupling relationship between wheel/rail excitation and spring structural dynamic characteristics. The structural frequency-domain fatigue analysis method is used to calculate the dynamic stress response and fatigue life of the spring. Firstly, the dynamic characteristics of the coil spring structure are considered, and a refined vehicle-track coupling dynamic model containing a series of dynamic and stiffness characteristics is established. Then, under wheel-rail excitation, the dynamic loads at both ends of the service-condition spring are extracted. Finally, the structural frequency-domain fatigue analysis method is used to calculate the dynamic stress response and fatigue life of the spring, which is compared and verified with the measured dynamic stress results. The results show that the dynamic characteristics of the coil spring itself are reflected in the maximum mode deformation at the middle of the spring and the maximum mode stress between the first and second coils under multi-mode frequency. Based on the coupling dynamic model, the calculated internal spring dynamic stress response is consistent with the measured results, and the dynamic stress peak value at 58Hz is more than three times that at other frequencies. Due to the close resonance frequency between the first-order natural frequency of the inner spring and the P2 resonance frequency of the wheel-rail system, internal resonance of the spring causes high stress on the inner side of the first two coils, and the analysis result of the shortest fatigue life at that location coincides with the actual fracture position. The shortest fatigue life of the outer spring is about 3.6 times that of the inner spring. Therefore, considering both the wheel-rail excitation and the dynamic characteristics of the coil spring itself, it is of great significance for the anti-fatigue design of the coil spring series to keep its natural frequency far away from the wheel-rail resonance frequency.
  • LIU Zongtong1, MA Jianjun1,2, GUO Ying1
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 237-245.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The effect of soil-structure interaction on structural dynamics is a nonlinear energy sink. Using Winkler foundation beam theory considering soil mass, the limited depth elastic medium is equivalent to the additional mass of the nonlinear energy sink system. The nonlinear dynamic model of the supported beam system on the elastic medium under harmonic excitation is established. The Galerkin and incremental harmonic balance method analyze the nonlinear dynamic response of a supported beam on the elastic medium. The correctness of the theoretical results is verified by numerical calculation, and the effectiveness of the nonlinear energy sink is analyzed. The vibration reduction effect of the elastic medium in different parameter ranges is revealed through parameter optimization and analysis, and the optimal parameter range is discussed. The results show that the elastic medium has an excellent inhibitory effect on the dynamic response of the supporting beam within a reasonable parameter range. It can quickly and effectively absorb the vibration energy under resonance conditions and has good robustness. The optimized nonlinear energy sink can reduce the resonance amplitude of the beam by more than 95% and has a wide vibration reduction frequency band. The research results show the vibration reduction mechanism of soil-structure interaction from a nonlinear energy sink perspective and provide a theoretical basis for structural vibration suppression based on the elastic foundation design.
  • HE Peitao1,2, WANG Shuangli1,2, GENG Xiaoming3, XIE Xiling1,2, ZHANG Zhiyi1,2
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 246-251.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To attenuate vibration transmission along the annular support in a compact shell, an active/passive vibration isolation support with piezoelectric actuators is proposed. The analysis of vibration control is carried out on the basis of the dynamic model of the vibration source-active/passive support-cylindrical shell system. The cylindrical shell is modeled by the Flugge shell theory and the wave propagation method. The vibration source, active/passive support, etc. are modeled by the finite element method. The coupled model is established on the frequency response functions of the subsystems. Based on the coupled model and ideal control assumption, the feasibility of active vibration control is investigated in the frequency domain. A vibration source-active/passive support-cylindrical shell experimental systemis constructed to verify the effectiveness of the control method. Simulation and experimental results show that the active/passive support vibration isolation support with piezoelectric actuators can significantly attenuate wide-band and line spectrum vibration of the shell.
  • SHI Gang, GAO Xinjun, ZHANG Hao
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 252-264.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Traffic, machine operations can generate ground vibrations, which can cause distress to adjacent structures, and disturb the operation of precision instrument. The adverse effects of ground vibrations can be eliminated or prevented by installation of various types of wave barriers, such as a row or multi-row of piles. However, construction of traditional piles can also generate adverse effects, such as mud, ground vibration or compacting effect. A new kind of environmental-friendly pile, called stiffed deep cement mixing (SDCM), is introduced to construct wave barriers in city. In order to investigate the screening efficiency of a row of SDCM piles in saturated soil, a 3D semi-analytical BEM-FEM coupling model is established to use a row of SDCM piles as active wave barrier, to isolate the ground vibrations generated by the machine foundation laid on the surface of saturated soil foundation. And the effects of the model parameters on isolation effectiveness are investigated and discussed in detail. The results show that a row of SDCM piles can isolate the ground vibrations successfully. The SDCM pile row with isometric core pile has a better screening efficiency than that of short core pile, and increasing the number of piles in a row can get a better vibration isolation effectiveness. Further, the net spacing between two successive piles has less effect on the screening efficiency. According to the results, it’s suggested in the design that the hole radius should take the value of 2~2.5λ_R (λ_R is the Rayleigh wave length) . The distance between the machine foundation and barrier can affect the screening effectiveness, and the larger the distance is, the poor the screening effectiveness is. Moreover, the SDCM pile wave barriers, which are made up of different precast core piles with the same overall dimension, can result the approximate equivalent screening efficiency.
  • ZHANG Heng1, ZHOU Yongjun1,2, WANG Yelu1, FAN Kaixiang1, ZHAO Yu1,2, XUE Yuxin1
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 265-275.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to study the influence of vibration marking on the deflection dynamic load allowance(DLA) of long slope bridge structure, taking 30m span continuous box girder bridge and five-axis vehicle as the research object, the irregularity based on the actual vibration marking form was simulated, and the vehicle bridge coupling vibration equation is established. With the help of ANSYS and APDL language, the direct integration method is used to solve the equation, and the deflection time history curves and the DLA of different midspan positions are obtained. The influence of the number, spacing and position of vibration markings on the deflection DLA of different midspan sections of continuous girder bridge is studied. The results show that the deflection DLA of continuous girder bridge with vibration marking is greater than that in the code value, and the maximum value of the former is 2.40 times than the latter; the number of vibration markings has little influence on the deflection DLA of the first mid-span in the travelling direction, but it has a great influence on the deflection DLA of the second mid-span; with the increase of the spacing of vibration markings, the deflection DLA of different midspan positions changes differently; the position of vibration markings has effect on the deflection DLA of different midspan positions. When the number of vibration markings groups is 6, the distance from the first vibration marking to the bridge end is suggested to be 4m, and the spacing is 4.5m. When the number of vibration markings groups is 4 or 5, the vibration marking setting should be selected according to different span layout. The research results can provide reference for the setting of vibration markings on bridge structures.
  • ZHENG Yongjin, WANG Li, LIU Zuoqiu
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 276-282.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Nonlinear phenomena widely exist in structural analysis. Obtaining the periodic response of nonlinear systems is crucial to analyzing the frequency response characteristics, bifurcation and stability characteristics of structures. Therefore, a method for solving the periodic response of nonlinear systems based on time finite element method is proposed. On the basis of Galerkin time finite element method, in this method, periodic boundary conditions are introduced and combined with Newton iterative method to solve problem. The advantages of this method are: (a) it can simply deal with nonsmooth periodic loads (such as step or impact periodic loads), and (b) it can directly calculate the transfer matrix and Floquet multiplier according to the system matrix of the time finite element, and then determine the stability of the periodic solution. Finally, the correctness, convergence and accuracy of the proposed time finite element method in the periodic response solution and stability analysis of nonlinear systems are verified by numerical examples.
  • WU Bingquan1,2, NI Wankui1,2, TUO Wenxin1,2, REN Siyuan1,2, CHEN Junting1,2
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 283-289.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to further study the influence of dynamic compaction on the stability of surrounding loess slope, the limit equilibrium arc strip division method was used to deduce and calculate the slope safety factor under dynamic compaction.Combined with the engineering example, TC-4850 blasting vibration meter was used to test the acceleration of the site monitoring points.Considering the common influence of elevation difference and measuring point distance, the matlab programming was used for multiple regression analysis of the field data.The analytical formula of vibration acceleration of slope particles under dynamic compaction was obtained in the paper. On the basis of obtaining the minimum safety factor, the influence of different directions of strong rammed load on the stability of loess slope was studied.The results showed that under the same load, when the angle between the direction of strong rammed load and the positive direction of the horizontal axis is 0o、45o、60o、270o、315o、330o、and 360o , the safety factor is less than or equal to 1. With the increasing of the pseudo-static coefficient, the safety factor becomes smaller and smaller. When the angle between the direction of strong rammed load and the positive direction of the horizontal axis is 90o、135o、150o、180o、225o and 240o , the safety factor is greater than 1.05. With the increasing of the pseudo-static coefficient, the safety factor also increases. The method is simple and easy to calculate. It’s can be directly used in practical engineering. This method can be applied to the practical engineering of loess slope.
  • LI Bingwei1, ZHU Hongmin1, LIU Shixiu2, CHEN Gang3
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 290-296.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    High-speed aircraft undergoes noise and vibration environment during the flight mission, and the environment is severe, complex, and difficult to predict. Therefore, a noise and vibration environment prediction method based on sound and vibration transmission is proposed. Firstly, the extravehicular fluctuating pressure field of aircraft under typical flying conditions is obtained by means of numerical simulation, fluctuating pressure wind tunnel test or engineering analysis. Secondly, through noise test or sound-vibration coupling simulation analysis, the sound-vibration transmission characteristics of aircraft are obtained. Finally, according to the obtained extravehicular pulsating pressure and sound and vibration energy transfer characteristics, combined with the specific flight parameters, the aircraft noise and vibration environment under the actual flight conditions is predicted. The method proposed in this paper is used to study the vibration environment prediction of an aircraft. It is verified by ground and flight tests that the prediction accuracy of vibration environment can reach 1.6dB. The prediction method of flight sound and vibration environment based on sound and vibration transmission proposed in this paper can be widely used in the fine environment design of missiles, rockets and other aircraft. It has important engineering significance for improving the overall performance, environmental adaptability and flight reliability of aircraft.
  • MOU Haolei1, GAO Fei2, WANG Zilong2, XIAO Pei2, FENG Zhenyu1, XIE Jiang1
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 297-307.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To study the vertical water-entry impact characteristics of civil aircraft typical fuselage section, the cylinder water-entry impact test was firstly carried out by using the water-entry impact test system. Secondly, the uniform grid fluid model and locally refined grid fluid model were established based on the LS-DYNA ALE method, and were verified by comparing the water-entry impact test results. Finally, the water-entry impact characteristics of fuselage section at 6.02m/s were studied based on the verified fluid domain model and fuselage section model, the difference between water-entry impact characteristics and rigid ground impact characteristics, and the water-entry impact response of fuselage section at different speeds were further analyzed. The results show that the ALE method has higher accuracy for the structure water-entry impact simulation, and the fluid model grids numbers and the water-entry impact calculation time can be greatly reduced when using the locally refined grid fluid model. The water-entry impact failure mode of fuselage section is consistent with the rigid ground impact failure mode, but the overall deformation degree of fuselage section decreases, and the deformation degree of cabin floor beam increases. The frames are still the most energy-absorbing structural components, and a large amount of impact energy are absorbed by the water, resulting in the acceleration at the floor rail is always smaller. With the increase of the water -entry impact velocity, the degree of bending and upturning of fuselage frames increases.
  • MENG Xianfeng1,2, LUO Meng3,4, JIANG Hui3, DAI Peng1,2, GAO Xuekui1,2, ZHAO Xingyan3, JI Jinwen1,2
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(1): 308-318.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to study the dynamic load characteristics of civil airport pavement during aircraft landing and taxiing, taking the Boeing 737-800 aircraft as an example, a three-dimensional numerical simulation model of the fuselage, landing gear and tires was established, based on the dynamic simulation software VI-Aircraft. The pavement simulation model was created according to the measured roughness data of an airport pavement, forming a set of simulation methods for aircraft landing impact considering aerodynamic variation characteristics. The reliability of the simulation method was verified by two methods of landing gear system drop test and aircraft ground kinematics theory analysis. In addition, the influence of various landing state parameters on the dynamic load characteristics of the pavement was systematically discussed, the quantitative value of the dynamic load coefficient of the pavement under the influence of different landing state parameters was clarified, and the influence rule and mechanism of various landing state parameters on the dynamic load response of the pavement were revealed. The results show that with the increase of landing mass, descending speed and roll angle, the dynamic load response of pavement is significantly enhanced. With the increase of heading speed, the dynamic load response of pavement decreases significantly and with the increase of pitch angle, the dynamic load response of pavement shows a trend of decreasing fluctuation. In the process of aircraft landing, the sensitivity factors of the dynamic load coefficient of the pavement from large to small are: heading speed, descending speed, landing mass, roll angle and pitch angle. In full consideration of the impact of various landing state parameters, the distribution range of the dynamic load coefficient DIM of the pavement is 1.18~1.80 in general The research results can be further extended to the analysis and research of aircraft landing on runway bridge.