28 March 2023, Volume 42 Issue 6
    

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  • LI Zhen1,LIU Qingkuan1,2,3,JING Hongmiao1,2,3,SUN Yifei1,WANG Yangxue1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 1-7.
    Abstract ( 278 ) Download PDF ( 112 )   Knowledge map   Save
    Vortex induced vibration (VIV) is easy to occur in long-span bridges, resulting in structural fatigue damage. It is necessary to grasp the influence of girder shape on VIV. To investigate the influence and mechanism of guardrail with different locations on VIV characteristics of streamlined box girder, the vortex induced vibration response, wind pressure distribution, lift coefficient, aerodynamic phase difference and vortex induced vibration contribution coefficient of bridge side railings at five locations were studied through segmental model wind tunnel test. The experimental results show that the inward movement of the railing on the windward side is beneficial to suppress the vertical bending vortex vibration, and the inward movement of the railing on the leeward side will slightly increase the vortex vibration response. The inward movement of the railing on the windward side will reduce the absolute value of the lift of the main beam, increase the dispersion of aerodynamic phase difference, and also reduce the contribution coefficient of vortex induced vibration at each position, which is considered to be the reason for the suppression of VIV.
  • SONG Xiaodong1,WANG Wei1,YANG Jianchao2,LIU Fei2,GAO Weiliang2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 8-15.
    Abstract ( 156 ) Download PDF ( 113 )   Knowledge map   Save
    To study the relationship between the anti-penetration performance of early-strength concrete and the curing age, the 35 mm ballistic gun and 35CrMnSiA reduced-ratio ogive-nose projectiles were used to conduct penetration experiments on the ultra-early-strength concrete named “UR50” under two curing periods. According to the experimental data, the penetration response characteristics of ultra-early-strength concrete at two curing ages were compared and analyzed. In order to further study the response mechanism of projectile penetrating ultra-early strength concrete, the response model of rigid projectile penetrating semi-infinite target is introduced for theoretical research, and the improvement of the penetration resistance of special steel fiber in ultra-early strength concrete is analyzed by using the Berezan formula. The experimental results show that the process of projectile penetrating ultra-early strength concrete target at low speed can be divided into two stages: impact cratering and stable penetration. The ultra-early-strength concrete can achieve the anti-penetration performance of 28 days after curing for 7 days. The response model of rigid projectile penetrating semi-infinite target was used to compare the predicted penetration depth with the experimental penetration depth of ultra-early-strength concrete with one dimension for 7 days and 28 days, and it was found that the maximum relative errors were 29.13 % and 8.48 %, respectively. The calculated unconfined compressive strength of ultra-early-strength concrete at two ages in the response model was corrected to make the calculated penetration depth conform to the actual results.
  • TANG Longfei1,2,ZHENG Chaorong1,3
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 16-23.
    Abstract ( 204 ) Download PDF ( 114 )   Knowledge map   Save
    The random decrement technique (RDT) has been widely utilized in the modal parameter identification of engineering structures, due to its advantage of rapid computation and low cost. Aiming at the shortcomings of subjective selection of truncation amplitude and sample duration in the RDT, which brings large error in the modal parameter identification, the genetic algorithm is adopted to revise the RDT and the improved RDT (GA-RDT) method is proposed, and then the GA-RDT method is applied in the aerodynamic damping ratio identification of an aeroelastic model of a supertall building. Firstly, the free decay curve obtained by the RDT is fitted and then the error is defined. The effect of the cut-off amplitude and sample duration on the optimization target is analyzed and the genetic algorithm is utilized to search the optimal solution of these two parameters. Secondly, based on the tip acceleration time history acquired by the aeroelastic model wind tunnel test, the aerodynamic damping ratio is identified by combining the GA-RDT and Hilbert-Huang transformation method. Finally, the aerodynamic damping ratio identified by the natural excitation technique (NExT) is regarded as the benchmark, and the identification accuracy based on the GA-RDT method and traditional RDT method are discussed. The results show that, when compared with the aerodynamic damping ratio identified by the NExT method, the corresponding results identified by the GA-RDT method under different wind speeds have an average error of less than 0.14% in the X, Y and torsional directions respectively, and the identification accuracy is much better than those identified by the traditional RDT method. Therefore, the feasibility of the aerodynamic damping identification method based on the GA-RDT method is verified.
  • YUAN Jianhui,ZHAO Rongzhen,MA Chi
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 24-30.
    Abstract ( 128 ) Download PDF ( 123 )   Knowledge map   Save
    Aiming at the classification difficulty caused by feature redundancy in high-dimensional fault feature set of rotating machinery, a dimension reduction algorithm of fault data set based on Local Principal Component Preserving Projection (LPCPP) is proposed. The algorithm integrates two ideas of inter-class separability criterion and principal component calculation with Locality Preserving Projection (LPP), which makes the algorithm have the ability to eliminate redundant features and reduce dimensionality reduction blindness, so that it can better retain the fault information with high value density and the main components of features that can reflect the operation status of machinery. The proposed algorithm is verified by the vibration signals of two different types of two span rotor systems, and the dimensionality reduction performance of the algorithm is evaluated by the separability index and the recognition accuracy of three different classifiers.  The results show that the algorithm can achieve the function of reducing the difficulty of fault classification and improving the accuracy of fault classification, which can provide a theoretical basis for data computing to accumulate the data resources with high value density and the engineering implementation of intelligent decision-making technology for rotating machinery based on "industrial big data".
  • LI Deng1,2,YAO Zhiyuan1,2,TU Yixiang1,2,LIU Yong3,WU Shijing1,2,WANG Xiaosun1,2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 31-38.
    Abstract ( 203 ) Download PDF ( 152 )   Knowledge map   Save
    Compared with plain waterjet, cavitating water jet can produce stronger impact forces and is thus being applied in all kinds of applications. Aiming at further improving the efficiency, a new type of cavitating waterjet called non-submerged dual cavitating waterjet is proposed. By using the Mixture model of multiphase flow and the RNG k-ε transport equation, the effects of outer nozzle width D0, outer nozzle extension length L and outer nozzle pressure P1 on the velocity, pressure, and vapor content are analyzed, as well as the impact characteristics under the optimal combination of D0、L、P1. The results show that the optimal flow field appears when D0 = 1.5mm and L = 2mm, and the optimal standoff distance under this condition is 20-25mm. Through analyzing the impact characteristics, it can be found that the non-submerged dual cavitating waterjet produces a larger volume of cavitation cloud and better impact effect, compared with the traditional central body cavitation nozzle. The results could provide a theoretical basis for the high efficient application of cavitating waterjet.
  • SHU Kun,SUN Yan,CHEN Yan
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 39-54.
    Abstract ( 212 ) Download PDF ( 80 )   Knowledge map   Save
    Ultrasonic assisted magnetic abrasive finishing technology adds ultrasonic vibration function on the basis of magnetic abrasive finishing, which can polish the surface to nano level in a short time . Because it has the advantages of good auxiliary grinding effect, good controllability and applicability, it has been applied in more and more fields. Firstly, the development of ultrasonic assisted magnetic abrasive finishing technology is briefly introduced, which is mainly analyzed and summarized from the aspects of surface roughness, material removal rate, microstructure and residual stress. Secondly, ultrasonic vibration process parameters are important factors affecting the grinding result. Optimizing the process parameters such as amplitude, vibration frequency, spindle speed and abrasive particle size can significantly improve the grinding effect. In addition, the appropriate machining time and machining clearance should be considered to accurately grind the complex surface. Finally, some defects in the research of ultrasonic vibration assisted magnetic abrasive finishing technology are put forward, and its future development trend is prospected.
  • HU Yinlong,WANG Kaiyi,CHENG Changjun,HUANG Chongqi,ZHU Zeqing,ZHENG Ruifei
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 55-60.
    Abstract ( 290 ) Download PDF ( 37 )   Knowledge map   Save
    In terms of the fact that the physical mass of inerters is often ignored in the existing research, a port-mass model for ball-screw inerters with physical mass consideration is proposed. Mathematical models and virtual simulation prototypes of a first-order system and a second-order system with a ball-screw inerter are established. By comparing the frequency responses of the mathematical model and simulation model, and through bench experiments, the accuracy of the proposed port-mass model is verified. Furthermore, based on a quarter-car vehicle model, the influence of the inerter physical mass on ride comfort is analyzed. The optimization simulation results show that there is an apparent difference in system performance between the cases with and without the physical mass consideration. Moreover, the optimization results indicate that comfort performance can be further improved based on the port-mass model. This demonstrates the necessity of considering the physical mass of inerters and the effectiveness of the proposed port-mass model.
  • ZHANG Zhi1,WANG Jiawei1,QIAO Yu2,ZHANG Jiazhen2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 61-68.
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    When the gas well buckles seriously, the tubing trajectory is complex, so the error of using the fluid transient model in the vertical well to solve the pressure fluctuation after shut in is too large, and the calculation results lose the reference value. Based on the perturbation method, a transient flow model suitable for the fluid in the buckling string is established in this paper. Taking into account the valve closing time, wellhead end opening and tubing buckling degree, the changes of pressure and flow rate of gas well after sudden shut in are analyzed and calculated. According to the calculation and analysis, when the tubing has spiral buckling, the local friction will be generated at the buckling part, and the pressure wave will be dissipated. Compared with the case without spiral buckling, the wellhead pressure is smaller. With the increase of valve closing time, the peak value of wellhead pressure decreases, and with the increase of valve closing time, the regularity of pressure change curve becomes less and less obvious; with the increase of valve closing time, the wellhead speed decreases more slowly, and the fluctuation amplitude and duration also decrease correspondingly. When the end opening of the valve is 0, the fluctuation of wellhead pressure lasts for a long time. The larger the pitch is, the smaller the tubing buckling is, the smaller the friction of the fluid in the tubing is, and the higher the wellhead pressure is. The calculation results of the model are closer to the real data, which has a positive guiding significance for the field operation.
  • GAO Bingwei1,2,SHEN Wei1,2,DAI Ye1,2,YE Yongtai1,2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 69-78.
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    In order to solve the problem of nonlinear friction interference that affects the tracking performance of electro-hydraulic servo system, an improved glowworm swarm algorithm is proposed to identify the parameters of friction model by combining adaptive step size with inertia factor. The glowworm swarm which has lost the ability to move is randomly optimized, and the global parallel search ability is introduced to improve the optimization ability of the glowworm swarm algorithm. Through function optimization and parameter identification tests, the results show that the improved glowworm swarm algorithm has better optimization performance. Finally, a friction state observer is built based on the identification model. For the chattering phenomenon of velocity zero in the simulation, the SIGMOID function is introduced to modify the friction observer. The experimental results show that the modified feedforward fuzzy controller can effectively restrain the adverse effects of friction on the servo system and further improve the tracking performance of the servo system.
  • JU Hanwen1,DENG Yang1,2,LI Aiqun1,2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 79-89.
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    The correlation between vehicle load, environmental temperature, and deflection of in-service bridge structures is complex. A high-precision correlation model between vehicle load, temperature, and deflection is important to bridge structural health monitoring. This study proposed a modeling method of bridge deflection monitoring data based on gated recurrent unit (GRU) neural network. The calculation method of vehicle load influence parameter was developed based on deflection influence line to solve the problem of time-domain discrete distribution of vehicle load monitoring data. On this basis, the correlation model of vehicle load influence parameter, temperature and bridge deflection based on GRU neural network was established. Taking a suspension as the example, the short-term, medium-term, and long-term correlation models were established. The prediction ability of stiffening girder deflection was investigated. A new separation method of temperature- and vehicle-induce deflection components was presented by using the correlation model. The suspension bridge case-study reveals that the predicted deflection based on the short-term correlation model is basically consistent with real-time deflection monitoring data. The medium- and long-term correlation models can accurately predict the deflection extremes in a certain time window. The temperature- and vehicle-induce deflection components separated by using the correlation model have favorable consistency with wavelet decomposition results.
  • DANG Yu,HE Yizhe
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 90-97.
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    Aiming at the visual measurement characteristics of the isolation bearing during an earthquake, that is, both the camera and the isolation bearing will move during an earthquake, and it is inconvenient to track the camera pose. This paper proposes a dynamic displacement measurement method of the isolation bearing without additional tracking of the camera movement. Firstly, the camera and the target are set in the orthogonal horizontal directions respectively, and the optical axis of the camera and the target plane are perpendicular to each other, and the scale factor method is used to calibrate the camera in each direction and time; Secondly, using the deep learning method, a YOLOv5 model is trained to automatically identify and locate the target, and the prediction box of YOLOv5 is enlarged and the target is repositioned by performing feature recognition and extraction on the enlarged image. Finally, the relative displacement of the target at the upper and lower connecting plates of the bearing is used to determine the dynamic displacement of the isolation bearing. The method was verified by photographing the mechanical performance test process of LRB500 isolation bearing. The results show that the error between the horizontal displacement time-history curve of the bearing obtained by this method and the displacement meter results at each moment is less than 1.0%, the absolute error of the horizontal displacement peak value is 1.042mm, and the absolute error of the vertical displacement peak value is 0.219mm. It shows that the method proposed in this paper has high detection accuracy, and can complete the deformation detection of the isolation bearing under the action of earthquake without tracking the camera pose.
  • SUN Hongjun1,L Pengfei1,DING Hongbing1,LI Jinxia2,SONG Chenrui1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 98-105.
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    Flow induced vibration generally exists in the field of engineering and nature. Due to the complexity and interdisciplinary, the flow induced vibration has always been one of the research hotspots in the academic community. The energy harvesting technology using passive turbulence control (PTC) to enhance flow induced vibration has attracted extensive attention. The study focused on the characteristics of flow induced vibration of cantilever vibrator by placing symmetrical square strip attachments with different angles on a smooth cylinder. The response of amplitude and frequency, output power and energy conversion efficiency, and the lift coefficient were obtained. The mechanism of passive turbulence control to enhance flow induced vibration was further revealed. The results showed that the maximum amplitude of PTC cylindrical vibrator is 2.0 D, which is 5 times that of smooth cylindrical vibrator; The maximum output power is 0.44 W, which is 14 times of the maximum output power of the smooth cylindrical vibrator. The reasonable placement angle of the attachment can make the vibration of the vibrator develop from vortex induced vibration to galloping, and obtain high output power and energy conversion efficiency, which provides necessary theoretical guidance and technical support for energy conversion and collection by flow induced vibration.
  • LI Xinran,JIN Wuyin
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 106-114.
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    Aiming at the problems that swarm intelligence algorithm optimization Support Vector Machine model (SVM)is easy to fall into local optimum and low accuracy in the field of rolling bearing fault diagnosis, a method of optimizing Support Vector Machine (SVM) based on improved Sparrow Search Algorithm (SSA) is proposed for fault diagnosis of rolling bearings. First, the evenly distributed Chebyshev chaotic map is introduced to initialize the sparrow population in order to improve the spatial distribution uniformity of the population. Then, the adaptive inertia weights are integrated into the location update of the discoverer of the sparrow algorithm. Finally, the optimal sparrow after the updated position is randomly disturbed to improve the global and local search ability of the algorithm and avoid falling into the local optimization. The algorithm is applied to the parameter optimization of support vector machine, and the ISSA-SVM fault diagnosis model is constructed to realize the classification and diagnosis of bearing fault signals. The analysis results of the rolling bearing fault diagnosis test show that the fault classification effect of the ISSA-SVM model is obviously better than that of the PSO-SVM, GA-SVM and SSA-SVM models, which can effectively identify the types of faults of rolling bearings.
  • LI Zhi1,2,XUE Tianqi1,2,YUAN Xiaolan1,2,ZHANG Yi1,2,QIAN Kai1,2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 115-125.
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    In this paper, Pushdown loading tests was carried out on RC spatial beam-column substructure under loss of a column scenario and a refined finite element (FE) model was established, which were used to study the progressive collapse resistance performance of RC spatial beam-column substructures with unequal spans. And the influence of horizontal constraints on the top of corner column, transverse reinforcement ratio at corner joint, and spatial action on the progressive collapse resistance of substructure was analyzed. The results indicated that for the RC spatial beam-column structure under the loss of a corner column, the structure cannot develop effective catenary action and the collapse resistance mainly relied on the beam action. It should be noted that the contribution of Vierendeel action cannot be ignored. Increasing the horizontal constraints at the corner column, the first peak load of the substructures will increase. However, the corner column may suffer greater shear stress and prone to cause shear failure. Installing an amount of transverse reinforcement at the corner joint could delay or mitigate the shear failure of the corner joint. Thus, progressive collapse resistance capacity of the substructures could be upgraded. Moreover, for the case of corner column failure, the spatial effects could not be taken as simple summation of the load resistance of the plain frame as the spatial effects may aggravate the shear failure of the corner joint.
  • HU Zhewen1,2,LI Jianbo1,2,LI Zhiyuan1,2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 126-133.
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    Under strong earthquake, the possible uplift-slip of the nuclear island common raft has a significant impact on the structural stress state. Refined simulation of the contact state on raft-soil interface and analyzing structure-interface-soil as a whole, are helpful to clarify the influence mechanism of uplift-slip effects on the seismic response of the structure. By applying the contact model named the penalty function method to simulate the contact mechanical behavior between the raft and the soil, the equivalent linear method for describing dynamic nonlinearity of the soil, and the viscoelastic boundary method for simulating radiation damping condition, a structure-interface-soil interaction model in consideration of uplift-slip effects was established. Furthermore, by applying the proposed model to evaluate the response of AP1000 nuclear island plant, the comparison of the simplified model of the raft-soil binding was achieved in consideration of the combined static and dynamic effects. The results showed that the peak of the structure acceleration response and the peak and the shape of the floor response spectrum changed obviously, which indicated that under strong earthquake uplift-slip of the raft had an adverse effect on the anti-seismic safety. It can be seen that uplift-slip effects should be considered in the seismic fortification of nuclear power structures.
  • WANG Yihang,PENG Zhenrui
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 134-142.
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    To obtain the boundary conditions of the finite element model which can accurately reflect the structural assembly relationship, combining the Kriging model and the hierarchical model updating technique, an identification method of the structural boundary conditions is proposed. Firstly, to weaken the influence of material parameter errors on the identification of boundary conditions and improve ill-posedness, the material parameters of finite element model are updated by using the measured free mode frequencies; then, boundary condition identification is performed on the basis of the updated model, and sensitivity analysis is used to determine the boundary parameters to be updated. Latin hypercube sampling is used for experimental design, and the minimum error between the measured constrained modal frequencies and the predicted frequencies of the Kriging model is taken as the objective function, and the particle swarm optimization algorithm is used to obtain the optimal parameters. Finally, the test results of a rocker arm link structure in a packaging machine show that the proposed method has better identification result compared with the traditional boundary parameters identification methods, and that the obtained boundary parameters and structural responses can have the better consistency with the actual structure.
  • LI Haiping1,2,TIAN Ruilan1,3,XUE Qiang1,3,ZHANG Yangkun1,3,ZHANG Xiaolong1,3
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 143-151.
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    Based on the nonlinear topological characteristics of non-smooth variable scale Smooth and Discontinuous(SD) limit system, the non-smooth variable scale crest frequency identification method is optimized and applied to the early fault signal detection of bearing. Using the periodicity of homoclinic-like orbit, the non-smooth random subharmonic-like Melnikov function is derived, which leads to the necessary and sufficient conditions for the occurrence of simple zeros in the mean square sense. The effects of non-smooth and noise coupling factors on the chaotic threshold of non-smooth variable scale SD limit system are revealed. The numerical simulation results show that the initial phase of weak signal leads to the deviation or unrecognizability of non-smooth variable scale-convex-peak method. When there is a deviation in frequency identification, a linear correction formula is given by using the geometric characteristics of the data; When the frequency is unrecognizable, the detection equations are constructed to make the convex peak frequency identification method still effective. Through an example of early fault of wheel set bearing of high-speed train, the possible fault location of wheel set bearing is determined by using the optimized non-smooth variable scale convex peak frequency identification method. The results show that the non-smooth variable scale convex peak frequency identification method can accurately identify the frequency of early fault signal of wheel set bearing, and the method is simple and accurate.
  • YU Gaoyuan1,2,LOU Yunfeng1,2,3,LI Junjie1,2,JIN Xianlong1,2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 152-158.
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    According to the architecture characteristics of domestic heterogeneous multi-core processor, a hierarchical communication parallel computing algorithm for structural transient analysis is proposed, which has important significance to improve the parallel efficiency of the system transient analysis on the entire large structure under the domestic heterogeneous multi-core and distributed memory parallel computers. Based on hierarchical communication and Newmark-HHT algorithm, a parallel computing system for a large-scale transient analysis was established, which can not only significantly improve memory access rate through the distributed storage of a large amount of data, but also significantly improve communication rate with the two-layer parallelization of the computational procedure. Hence, it can improve the efficiency rates of parallel computing of large-scale transient analysis by fully exploiting the architecture characteristics of the domestic heterogeneous multi-core and distributed memory parallel computers. Finally, typical numerical experiments were used to validate the correctness and efficiency of the proposed method. Then a parallel transient analysis of the high-rise building with over ten-million-DOF was performed and ten thousands of core processors were applied.
  • KANG Yingzi1,YANG Jinbao1,XIE Xinxing2,ZHANG Qu2,SHANGGUAN Wenbin1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 159-165.
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    The sound insulation pad is mainly used to isolate the noise of engine and prevent it from reaching the passenger compartment. It is generally an ABA (absorption layer - insulation layer - absorption layer) structure. The absorption layer (A) in ABA structure is porous felt, which is often made of fibrous materials. In this paper, kapok fiber and superfine fiber are used to make porous felt. The sound absorption coefficients of two kinds of porous felt are tested and compared. Two kinds of fibers are used to make the ABA structure samples, and the sound insulation performances are tested. The calculation model of the sound insulation performance of ABA structure is established and the validity of the model is verified. The model is used to calculate and analyze the sound insulation performances of ABA structures with different material composition and thickness parameters.
  • ZHAO Zhihong1,2,WU Dongdong1,DOU Guangjian1,YANG Shaopu2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 166-171.
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    Aiming at the problems that the fault sample was scare and over-fitting in traditional deep neural network model in small samples and poor generalization performance, a fault diagnosis method based on CNN-BiGRU Siamese network was proposed. Siamese networks were composed of two convolution neural networks and bidirectional gated recurrent unit that had the same structure and shared weights, the bearing sample pairs of the same category and different categories were constructed to input the Siamese network and the similarity was compared based on the L1 distance to achieve fault classification. Compared with the traditional deep neural network, the Siamese network adopted the method of sample pair training, which increased the effective training times of the network model under the same number of samples, so as to improve the performance of bearing fault diagnosis. The convolution neural network and bidirectional gated recurrent unit were used to construct the Siamese network, which can extract spatial and temporal features from vibration signals at the same time, improved the accuracy of feature extraction. The fault diagnosis experiment was carried out by using the measured bearing fault signal, and compared with other deep neural network models. The experimental results show that the CNN-BiGRU Siamese network method still had superior diagnostic performance in the case of small samples and had a certain engineering application value.
  • WANG Xiaofei1,HU Shaobin2,WANG Enyuan1,ZHANG Qiang3
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 172-179.
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    In order to study the impact and vibration hazard effects of dry ice powder pneumatic rock breaking, the experiment tested the gas pressure change in the dry ice tube and the vibration speed of the ground surface, and the attenuation law of dry ice powder pneumatic rock breaking vibration was studied by the Hilbert-Huang transformation method. The research results show that: 1. The maximum vibration velocity of dry ice powder pneumatic rock breaking drops below 2.5cm/s at 11m, which is a new rock breaking method with little vibration;2. The peak pressure in the fracturing tube is measured to reach 50.85MPa, and the TNT equivalent of the calculated energy conforms to the Sadowski formula; 3. The time-frequency analysis of the dry ice powder pneumatic rock breaking vibration signal is carried out by using HHT, and the energy is mainly distributed in the frequency domain. 0-100Hz, vibration duration 0.3s.
  • PAN Yi1,WANG Meng1,2,ZHOU Yang1,LI Xuemei1,SUN Beibei1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 180-187.
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    To improve the energy absorption characteristics of negative stiffness metamaterials, a reinforced cylindrical negative stiffness metamaterial structure was proposed, which was composed of cylindrical inclined beam elements and internal periodic plane inclined beam elements. Its energy absorption performance was mainly realized by the negative stiffness of the inclined beam element. The mechanical properties of the structure were studied by theoretical analysis and finite element analysis. The results show that the greater the ratio of height to thickness of the inclined beam elements is, the more obvious the negative stiffness and bi-stable performance of the structure are, and the closer the ratio of height to thickness of the two inclined beam elements is, the better the stability of the structure is. At the same time, compared with hollow cylindrical metamaterial structure with negative stiffness, it is confirmed that the reinforced structure improves space utilization rate and energy absorption effect. Finally, taking the non-explosive separation device of spacecraft as the application background, the novel negative stiffness metamaterial energy absorbing structure was optimized based on Kriging agent model. The total energy absorption level and unit energy absorption level are increased by 20.47%
  • JIAN Bin1,MA Hongye2,WANG Ke2,YAN Bo3
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 188-195.
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    This paper proposes two kinds of nonlinear electromagnetic vibration absorbers: the quasi-zero stiffness main structure coupled nonlinear RLC circuit and the quasi-zero stiffness main structure coupled linear RLC circuit. First, the nonlinear electromagnetic coefficient is derived. Then, the governing equations of two kinds of nonlinear electromagnetic absorbers are established and corresponding displacement transmissibilities are derived by the harmonic balance method. Last, Jacobin Matrix is used to judge the stability of solutions. Results show that two kinds of nonlinear absorbers can improve the vibration absorption performance by 64% and 77% compared with that under the condition of the main structure without external circuit. The former has more advantages in low-frequency vibration absorption. Moreover, it will cause quasi-periodic vibration at a specific frequency when the resistance is low. Both of them have optimal design parameters.
  • MIAO Xiangyao,WU Xing,LIU Xiaoqin,TANG Linjiang
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 196-201.
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    It is essential to find the location of the fault in large bearings to improve the efficiency of the maintenance. A method for fault localization using single acoustic emission sensor is proposed. The dispersion characteristics of Lamb wave are applied to estimate the propagation velocities of possible modes for the bearing annular structures. The arrival time differences of possible modes with the corresponding frequency bands are calculated by using the Akaike Information Criterion (AIC). The distance between the sensor and the acoustic emission source can be estimated according to the velocity difference and the time difference. For the uncertainty of the propagation modes and the twin locations, a secondary localization procedure is carried out by changing the sensor position. The unique location of the acoustic emission source is obtained after filtering out the unreasonable propagation modes. The effectiveness of the proposed method is verified by the pencil lead breaking experiments on the cylindrical roller thrust bearing.
  • ZHAI Xinxian1,ZHAI Yanwei2,LIU Qinyu1,ZHAO Xiaofan1,REN Zhu’an1,GUO Zhaoyang1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 202-211.
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    Coal seam water injection is one of the main measures to prevent coal bump in the gateways of fully mechanized caving face. In order to study dynamic mechanical properties and mechanical parameters of water-bearing coal specimens, the uniaxial impact compression tests of cylindrical coal specimens with different moisture contents were carried out by using the Hopkinson pressure bar (SHPB) test system. The effects of moisture contents and impact velocities on the dynamic stress-strain curves, dynamic mechanical parameters, and dissipation energies of coal specimens were studied. (1) Dynamic mechanical parameters of coal specimens are related with their impact velocities and moisture contents. When the moisture contents of coal specimens are a constant, the dynamic compressive strength and dynamic elastic modulus of coal specimens are positively correlated with the impact velocities. When the impact velocities are a constant, the dynamic compressive strength and dynamic elastic modulus of coal specimens are negatively correlated with their moisture contents. (2) The damage dissipation energies of coal specimens during impact directly reflects their degree of micro-fracture development. With the increase of impact time, the damage dissipation energies of coal specimens increase, and the damage dissipation energies reach the maximum when the coal specimens collapses. When the moisture contents are a constant, the failure dissipation energies of coal specimens are positively correlated with the impact velocities; When the impact velocities are a constant, failure dissipation energies of the coal specimens are negatively correlated with their moisture contents. (3) The ratio of damage dissipation energy to failure dissipation energy of coal specimen is defined as its damage factor. Based on the uniaxial impact compression tests results of coal specimens, their damage-viscoelastic constitutive model and constitutive relation were established. The dynamic stress-strain experimental curves of coal specimens with different moisture contents were theoretically fitted. The fitting degree between the theoretical and the experimental curves was higher, so the theoretical curves can be used to represent the stress-strain relationship of uniaxial impact compression coal specimens. The conclusions provide a theoretical basis for the prevention of rockburst by coal seam water injection into deep-holes in coal bump mines.
  • PANG Junheng,DONG Sheng
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 212-223.
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    Accurate damage identification is an important guarantee for the safe operation of the offshore platform. Wavelet packet analysis can effectively reveal the partial feature of the signal, this paper proposes a sensitive to the damage of scheme selection principle of the wavelet packet decomposition, The wavelet packet energy change rate of acceleration signal before and after structural damage is taken as residual, the elastic modulus of the structure is taken as the parameter to be updated, a new objective function is constructed by sensitivity analysis for model updating and structural damage identification. Applying the above identification method to the simply supported beam model can accurately identify the existence, location and degree of damage, which verifies the feasibility of the method. The identification and analysis of the signal polluted by noise shows that the method has certain robustness, and the signal with serious noise pollution is denoised by wavelet threshold, the identification effect is improved compared with that before noise reduction. The method is applied to the offshore jacket platform model, and the damage scenario of different height and different type of member can be identified effectively, indicating that the method is also suitable for multi-storey complex structures.
  • ZHANG Bin,ZHANG Xiaofang,MA Xindong,BI Qinsheng
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 224-231.
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    Since there exist coexisted stable attractors with different attracting basins, when the coupling of different scales involves the vector field, complicated dynamical behaviors can be observed in the multi-stable system with wide science and engineering background. The paper aims at the influence of the coexisted stable attractors on property of the bursting oscillations as well as the mechanism in the multi-stable system. Based on a classical Hatley oscillator, by introducing external periodic excitation, when the frequency is far less than the natural frequency, different forms of bursting oscillations can be obtained with the variation of parameters.  Regarding the whole exciting term as a slow-varying parameter, we can derive the equilibrium branches and their bifurcations with the variation of slow-varying parameter by the stability analysis of the equilibrium point of the generalized autonomous fast subsystem. It is found that there exist several situations with different coexisted stable attractors. Here we consider three typical cases, where the characteristics of the coexisted attractors and the influence of their attracting basins on the bifurcation is presented. Accordingly, the bifurcations at the transitions between the quiescent states and spiking states are obtained, which can be used to explore the mechanism of the bursting oscillations. It is pointed out that when the trajectory passes across the attracting basins of the coexisted attractors in turn, the associated attractors may affect the structure of the bursting oscillations, which leads to complicated bursting oscillations. However, when the trajectory only passes across the attracting basins of some of the stable attractors, there may exist coexisted bursting attractors, which correspond to different initial conditions.
  • WANG Yangxue1,LIU Qingkuan1,2,3,JING Hongmiao1,2,3,LI Zhen1,SUN Yifei1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 232-239.
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    Vortex-induced vibration (VIV) is a kind of wind-induced self-limiting vibration with both forced and self-excited characteristics, which is easy to occur in long-span bridges at low wind speeds. The railings, subsidiary facilities of the bridge deck, have a significant influence on the VIV performance, as a results of its variation in aerodynamic shape of the main girder. To reveal the influence and mechanism of inclined railings on VIV performance of streamlined box girder. The pressure distribution and displacement respond of sectional model were carried out by wind tunnel tests. The VIV response, mean and fluctuating wind pressure coefficient distribution were comprehensively studied. Meanwhile, correlation and contribution coefficients, as well as phase difference between local aerodynamic force and vortex-excited force also were comprehensively studied. The results indicate that when the sidewalk railing inclined inward, the greater the inclined angle, the more obvious the vibration suppression effect. When the sidewalk railing is inclined outward, the vibration suppression effect of the main beam with 10° inclined outward is better than that of the main beam with 20° inclined outward; compared with the conventional vertical railings, the main reasons why the railings inclined 20° inward and 10° outward have obvious vibration suppression effect are as follows: the fluctuating wind pressure coefficients on the upper and lower surfaces of main girders are considerably lower, decreasing by 61.54 % in the most obvious regions; the correlation coefficient between local aerodynamic force and vortex-excited force is reduced by about 33.33% on average, in most areas of the upper surface of the main beam.; the vortex-induced contribution coefficients are reduced to varying degrees in the upstream front, downstream tail and most areas of the lower surface; the continuity of the phase differences between the measurement points are interrupted, and the phase differences become scattered.
  • BIN Fengjiao, GUAN Rui, LIU Guolin, ZENG Yu, WEI Zheng
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 240-247.
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    Euler-Bernoulli beam model and one-dimensional spring oscillator model are the dynamic theoretical basis of atomic force microscope (AFM). In this paper, a new method for calculating the equivalent damping was proposed, and the equivalent mass, equivalent stiffness and equivalent damping simplified from Euler-Bernoulli beam model to one-dimensional spring vibrator model were calculated using two simplified methods: deflection curve function and first-order vibration mode function, and the two simplified methods were compared. On the basis of equivalent parameters, the response amplitude of cantilever beam excited with fixed end displacement was further discussed. Finally, the frequency sweep experiment of the needle free probe away from the sample was designed. The experimental results show that the theoretical results obtained by simplifying the first-order mode function are in good agreement with the experiment. The results provide a theoretical reference for the study of the kinetic properties of atomic force microscope.
  • YANG Jiasong1, LIU Xiaoqin1, XU Kai1, WANG Dongxiao1, WU Xing1,2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 248-254.
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    Aiming at the problem of bolt loosening at the joints of industrial robots, an electromechanical coupling model was established according to the robot joint structure, and then the base loosening was introduced to establish the system dynamics model of bolt loosening. The current signal of the simulation model is analyzed, and the law between the current signal and the bolt loosening fault is obtained. The research shows that in the case of loosening, sidebands appear near the current frequency of the motor, pulse shocks appear in the time-domain waveform, and energy fluctuations appear on the time-frequency diagram. The analysis results of the proposed model are in good agreement with the experimental data, and the research results have important reference value for the modeling and diagnosis of industrial robot joint bolt loosening faults.
  • YANG Shu1,2, CHEN Pengyu1,2, JIANG Feng1,2, PEI Lianzheng1,2, QI Chang1,2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 255-262.
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    For ballistic impact protection, 1060 aluminum alloy re-entrant circular (REC) and traditional re-entrant (RE) hexagonal honeycomb sandwich panels were designed and fabricated. The dynamic response and protection performance of the two types of honeycomb sandwich panels under low-speed ballistic impact load were studied and compared by using steel cylindrical projectile low-speed impact test and finite element (FE) numerical simulation. Using the verified FE model, the effects of ballistic speed on the maximum permanent compression, local Poisson’s ratio and energy absorption partition of two types of honeycomb sandwich panels under low-speed ballistic impact were simulated and analyzed. Finally, the effects of structural parameters such as circular cell wall radius and cell length of REC honeycomb cell on the low-speed ballistic impact response of sandwich panel were studied. The results show that compared with RE honeycomb, REC honeycomb sandwich panel has smaller maximum permanent compression and better ballistic performance under the same ballistic impact load, and the advantage is more obvious at low speed; With the decrease of cell length and circular cell wall radius, the ballistic performance of REC honeycomb sandwich panel can be further improved.
  • XU Jie1, ZANG Duyang2, WANG Guozhang1, LIN Jiyan1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 263-271.
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    The disc ultrasonic concentrator combines with the piezoelectric tube to achieve the large radiation scope. Traditional research on the vibration of the ultrasonic concentrator is based on the one-dimensional theory which ignored the effect of height on vibration. Whereas, the actual vibration of the disc ultrasonic concentrator is the coupling of radial and longitudinal vibration. The object of the analysis is the conical disc ultrasonic concentrator because of the simple structure and easy process, which the diameter is close to the longitudinal dimension. The equivalent elasticity method is used and the mechanical coupling coefficient is introduced to analyze coupled vibration of this concentrator. The electromechanical equivalent circuit, the resonance frequency equations and the radial displacement amplification of the ultrasonic concentrator are derived. Moreover, the dependences between the coupling coefficient, the resonance frequency, radial displacement magnification and geometric size are analyzed. The coupled vibration modes of the ultrasonic concentrator are simulated and the numerical resonance frequencies are obtained from the finite element analysis. The theoretical analyses are consistent with the numerical results, which verifies the theoretical derivation. The conclusion provides the theoretical research basis for the engineering application for the ultrasonic concentrator and the radial composite transducers.
  • HUANG Linsen, XU Zhongming, ZAN Ming, ZHANG Zhifei, HE Yansong
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 272-279.
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    In the field of sound source identification, it is a challenging task to identify the target sound source stably and accurately, especially in the middle- and low-frequency range. This paper proposes a fast iterative Cauchy threshold algorithm (FICTA) to identify the sound source and achieve robust sound source location in the middle and low-frequency range. Compared with the other three classical penalty function methods (including Tikhonov regularization method, wideband acoustic holography algorithm and interior point method), the Monte Carlo Analysis shows that the proposed method could obtain the stable sound pressure reconstruction results whose average reconstruction error is below 5% in the medium- and low-frequency range, and it has favorable distance-adaptability and signal-to-noise ratio-adaptability to the inverse problem of the sound source identification.
  • FANG Shizheng1, LI Weiyu2, YANG Yang1, CHEN Cheng1, XU Peng3
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 280-288.
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    With the development of deep rock engineering, the mechanical response of rock under in-situ stress needs to be studied. In this study, the dynamic characteristics of deep rock under hydrostatic pre-stress is carried out by using the split Hopkinson pressure bar (SHPB) experimental system. The effects of hydrostatic pre-stress and dynamic load rate on rock dynamic strength and dissipated energy are analyzed, and the rock failure characteristics are also studied. Results show that the dynamic strength of rock shows a significant rate effect, which increases with the increase of impact air pressure, showing a linear positive correlation; and it will increase nonlinearly with the increase of hydrostatic pre-stress, and has a well correlation after binomial fitting. As to energy evolution, it is found that the energy absorption proportion of rock increases with the increase of impact air pressure, and the hydrostatic pre-stress has an opposite effect on the rock energy absorption proportion, which reflects the constraint effect of hydrostatic pre-stress on rock deformation. Finally, the rock apparent failure mode is analyzed. It is found that the rock failure is mainly controlled by shear cracks at low hydrostatic pre-stress. With the increase of hydrostatic pre-stress, shear crack and circular crack appear simultaneously in the sample. The research results can provide basic parameters for deep rock engineering construction.
  • JIANG Zecheng, GAO Yun, LIU Lei, CHAI Shenglin
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 289-297.
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    The effects of four different inflow angles (α) on the vortex-induced vibration response of a two-degree-of-freedom cylinder were studied using the two-dimensional unsteady Reynolds-averaged N-S equation and shear stress transport k-ω model, combined with the fourth-order Runge-Kutta method. The effects of different incoming flow angles on the amplitude of vortex-induced vibration, structural vibration frequency, locking interval, vortex shedding mode, Strouhal number, hydrodynamic coefficient and energy capture efficiency are compared. The numerical results show that the change of the incoming flow angle will make the vortex-induced vibration response of the cylinder produce multi-frequency characteristics, and with the increase of the incoming flow angle, the amplitude in the y direction gradually decreases and the amplitude in the x direction gradually increases. Different incoming flow angles have obvious locking phenomenon, but the width of locking interval has no obvious change on incoming flow angle. With the increase of inflow angle, the root mean square of force coefficient in y direction and the mean value of force coefficient in x direction both tend to decrease.
  • LI Xuemei1, WANG Meng1,2, LIU Yanhao1, PAN Yi1, SUN Beibei1
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 298-306.
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    To ensure the reliable connection and separation of the separation device in the launching process of spacecraft, the contact dynamics and separation process of a certain type of non-explosive separation device was researched. The non-explosive separation device used shape memory alloy spring as the driving source. The contact model was analyzed and the contact parameters was determined according to the contact theory. The dynamic simulation model was established and simulation was calculated. The simulation results show that the separation shock is less than 300g, which is consistent with experimental results. The recovery time of SMA spring in separation device, the preload force and spring stiffness were researched for the influence of the separation process. The results show that the recovery time and preload force have opposite effects on the separation device of shock response, the values must be taken into account comprehensively. Among the spring parameters, the stiffness of the segment separation spring and the bolt separation spring have the greatest influence on the separation shock.
  • ZHAO Xiangwei, FU Liang, YANG Zhen, ZHANG Chenhui, YANG Yang, XIE Zhenzhen
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 307-312.
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    In order to reduce the vibration of rocket sled motion on track, the damping slipper was designed, and the dynamic characteristics of that was numerically analyzed. Firstly, the constitutive parameters of natural rubber in the damping layer of damping slipper are determined by plane compression test and empirical formula, then it’s nonlinear stiffness was obtained from the finite element model, secondly, the nonlinear dynamic model of damping slipper was established, solved and verified by experiments, the calculation results show that: the damping slipper has better damping capacity than the traditional slipper, and it’s damping capacity increase with the increase of load, but the introduction of rubber makes it appear ‘jump’ under the condition of large load and high overload, according to this phenomenon, the working boundary of the damper slipper is determined, in the typical working conditions, the load of each damping slipper should be less than 311kg at 1 Ma and Less than 181kg at 2 Ma.
  • WANG Jinghui1, JIANG Yi1, YANG Changzhi2, WEI Dongdong2
    JOURNAL OF VIBRATION AND SHOCK. 2023, 42(6): 313-324.
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    In order to study the effects of liquid propellant sloshing with different liquid filling ratios on rocket launch accuracy under cold ejection load, the liquid rocket with cold ejection is studied in this paper. The dynamic response of propellant sloshing is studied by fluid-solid coupling technique based on MPS method. Finally, the interference on rocket tank and influence on initial disturbance of rocket and mechanical characteristics of adaptor at different propellant liquid filling ratio are obtained. The results show that the larger the liquid filling ratio is, the greater the force of liquid propellant on a single tank is; In a certain range, with the increase of the filling ratio, the propellant sloshing makes the off-orbit pitch and yaw angular velocity of the rocket increase first and then decrease;  When the liquid filling ratio is 80%, the initial disturbance of the rocket and the force of the adapter are worse. Propellant sloshing can not be ignored in the dynamics study of liquid rocket cold ejection.