28 January 2024, Volume 43 Issue 2
    

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  • YANG Lijun1,PENG Linxin2,CHEN Wei3
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 1-11.
    Abstract ( 377 ) Download PDF ( 217 )   Knowledge map   Save
    As a new generation of advanced composites, functionally graded carbon nanotube reinforced composite (FG-CNTRC) has been widely concerned by researchers because of their excellent mechanical properties. In this paper, the FG-CNTRC beam on Pasternak foundation is taken as the research object. Based on different high-order shear deformation theories, a meshless method with interpolation characteristics, the stable moving Kriging interpolation (SMKI) is applied to solve the free vibration and buckling problems of FG-CNTRC beam on Pasternak foundation. Based on stable Kriging interpolation and different high-order shear deformation theory, the displacement field of FG-CNTRC beam is derived. The free vibration and buckling control equations of FG-CNTRC beam on Pasternak foundation are obtained by using Hamilton principle and minimum potential energy principle respectively. The relevant program is compiled by MATLAB. The comparison between the solution in this paper and the analytical solution or the literature solution proves the effectiveness and accuracy of this method in calculating the free vibration and buckling of FG-CNTRC beam on Pasternak foundation. At the end of the paper, the effects of different high-order shear deformation theory, foundation coefficient and carbon nanotube volume fraction on the natural frequency and buckling critical load are also discussed.
  • ZHANG Zhichao1,Lv Kaikai1,CHU Gaofeng1,QI Hongrui2,WANG Fangwen1
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 12-21.
    Abstract ( 243 ) Download PDF ( 74 )   Knowledge map   Save
    This paper proposes a simulation method for the dynamic response of the compressed 102-type coupler and draft gear based on test data, and then studies the dynamic performance of the heavy-haul locomotive and its 102-type coupler and draft gear for the 10,000-ton heavy-haul train with double locomotive traction marshalling. Firstly, based on the structural characteristics and compressed stability mechanism of 102-type coupler and draft gear, the weighted discrete method is used to simplify the draft gear into multiple impedance force elements with the same hysteresis characteristics, and the shear stiffness is introduced to consider the shear effect between these impedance force elements. By this way, the dynamic model of 102-type coupler and draft gear is established to simulate the one-side compressed characteristics of the coupler shoulder and draft gear accurately. And then the model of 10,000-ton train with the marshalling of “master locomotive + re-connected locomotive + freight vehicle + dummy freight train” is developed by using the substructure method; Then the shear stiffness between the discrete impedance force elements is confirmed and this train dynamic model is also verified by comparing the simulation results with test data. Finally, the influences of track conditions, structural parameters and locomotive electrical braking forces on the train dynamics response and running safety are calculated. The results indicate that the large locomotive electric braking forces on small radius curves are very dangerous for the train running safety; With the increases of the coupler free angle and the lateral stiffness of locomotive secondary suspension, the coupler rotation angle and locomotive running safety index increase gradually, but too large lateral stiffness may strength the wheel-rail lateral interaction.
  • WANG Zihao1,SUN Tiezhi1,ZHANG Guiyong1,2
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 22-31.
    Abstract ( 178 ) Download PDF ( 97 )   Knowledge map   Save
    The pressure wave mechanism is one of the cavitation flow mechanisms. The generation and propagation of pressure wave is an important source of cavitation instability. In this paper, three-dimensional hydrofoil cavitation flow is studied based on compressible fluid solver and detached-eddy simulation (DES). The results show that the pressure wave is generated by the pressure wave generated by the collapse of the cloud cavity. The propagation process of the pressure wave causes the shorten of the sheet cavity and the high-pressure pulse on the surface of the hydrofoil. The pressure wave is strongly disturb the motion of the vortex. The stable vortex structure on the surface of the hydrofoil is rolled up and replaced by the small-scale vortex structure. The dynamic mode decomposition method is used to analyze the characteristics of the flow field. The first-order mode represents the basic framework and main characteristics of the flow field. The pressure wave effect and the evolution of attached sheet cavity occupy the main energy of the flow field.
  • WANG Li1,2,YANG Yu2,LIU Guoqiang2,WANG Xiaguang2,LI Jiaxin2,REN Yipeng2
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 32-41.
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    In order to realize the condition-based maintenance and formulate the inspection and maintenance scheme during the service, probability of detection (POD) for guided wave damage monitoring technology must be clarified, as a new nondestructive testing method. This paper presents a novel POD computation method for guided wave based on signal response analysis model. First, the statistical computation model of POD is obtained by establishing the mapping relationship between the damage features of online response guided waves and fatigue crack. Then, by analyzing the quantitative effect of uncertainties of fitting parameters on the statistical computation model, POD computation models under different confident levels are obtained. The proposed method is validated on fatigue cracks monitoring experiments on metal center-hole and lap specimens. The results show that damage features, fitting functions and transducers monitoring schemes all have effects on POD, and the detectable crack length under 95% confidence level and 90% detection probability for center-hole and lap metal structures are about 2.6 mm and 9.5 mm.
  • GONG Bo1,ZHANG Zhengchuan1,YIN Junlian1,XU Rui1,LI Ning2,WANG Dezhong1
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 42-51.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to study the unsteady cavitation flow and its induced vibration characteristics in the water-jet pump, a high-speed camera and digital signal synchronization measurement platform was built. The cavitation flow, pressure pulsation, and vibration signals in the pump at different cavitation levels were acquired and analyzed. Empirical modal decomposition (EMD) and Hilbert-Huang Transform (HHT) were introduced to process and analyze the vibration signals. The results show that the cavitation of the top gap and the leaky cavitation of the top of the lobe appear in the water-jet pump. With the decreasing of inlet pressure of pump, the cavitation flow structure in the tip area of the blades develops from filamentary to sheet and then to cloudy. The rapidly rotating cavitation cloud will show an extremely unsteady characteristics, and the tailing of cavitation cloud will fall off to form perpendicular cavitation vortexes (PCVs); the small-scale PCVs dissipates in the middle of the flow channel, and with the further intensification of the cavitation, the scale of PCVs increases and moves to the pressure surface of the adjacent blade, resulting in the degradation of the water-jet pump performance. The change of flow structure characteristics with cavitation levels lead to a corresponding change in pressure fluctuation and induce an increase in vibration. The results of Hilbert-Huang transform show that the development of sheet cavitation and the collapse of large scale of cloudy cavitation vortex induce the increasing of broadband vibrations in the high frequency region; the PCVs induce rapid increasing of pressure fluctuations and vibrations at low frequencies. The trends of amplitude of high frequency, rotating frequency and shaft frequency at Hilbert marginal spectrum can be used to reflect the flow characteristics in the waterjet pump.
  • ZHAO Feng1,2,HUO Yaqi1,CHEN Lumin1,DU Wenliao1,CAO Shuqian2,FENG Guizhen3
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 52-59.
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    There exists problem that the dynamic stiffness of QZS isolators increases when the loaded mass deviates from the static equilibrium position, which influences the performance of vibration isolation at low frequency. A novelty constant QZS isolator is proposed herein based on the negative stiffness mechanism of two pairs of oblique bars. The force and stiffness expressions are derived. The QZS conditions are derived by considering that stiffness and its second order derivation are equal to zero at the static equilibrium position. The parameter conditions of nonlinear stiffness, constant QZS and zero stiffness are determined via discussing the influence of parameters on stiffness features. According to the static analysis, a constant QZS prototype is designed and tested for force-displacement curves, which shows better accordance with theoretical prediction. Furtherly, the constant QZS prototype and the corresponding linear isolator are tested by using laser vibrometer to respectively obtain their displacement responses and transmissibility. The dynamic experiment results show that the transmissibility of the constant QZS isolator is wholly lower than that of the corresponding linear isolator, the initial frequency of vibration isolation of the constant QZS isolator is less than 1.5 Hz but 4.5 Hz for the corresponding linear isolator. In summary, the proposed constant QZS isolator not only can realize any value of constant QZS but also can be conveniently fabricated by using ordinary bars and springs, which presents superior performance of vibration isolation at low frequency.
  • SU Yong1,HE Jiang2,ZHANG Miao2,GONG Wuqi1
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 60-70.
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    In addition to the self-excited excitation of high-pressure fluid in the tube, the kerosene pipeline in the liquid oxygen kerosene rocket engine is also subjected to external excitation such as external pressure pulsation and engine body vibration. Therefore, strong vibration often occurs, which has seriously threatened the safety of the rocket engine.In this paper, the vibration characteristics of the conveying pipeline are studied by using the established three-dimensional pipeline model including bellows, multi-section bends and other auxiliary structures, combined with the two-way fluid-solid coupling method.The results show that the low-frequency vibration of the pipeline is caused by the self-excited pressure pulsation of the fluid, and the high-frequency vibration is derived from the vibration of the engine body, while the external pressure pulsation excitation has no significant effect on the pipeline vibration.The visualization results show that the severe vibration position of the pipeline thermal test is mainly concentrated between the inlet and outlet and the two bellows.Bellows, elbows, and supports have high stress values, making them risky positions vulnerable to structural failure that need to be focused on. The findings of this study are significant in a good way for rocket engine structural optimization.
  • LI Zhengliang1,2,WANG Bangjie1,WANG Tao3,4
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 71-78.
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    The tension suspension-braced transmission structure is a new type of transmission structure suitable for mountainous terrain, which is sensitive to wind load. In this regard, a nonlinear finite element analysis model of wind-induced vibration is proposed for the transmission structure, and the wind-induced vibration response of the structure is analyzed. Firstly, the tangent stiffness matrix of the three-dimensional rod element for the bracing suspension and transmission line, considering the geometric nonlinearity of structures, is derived through the relationship between the element strain energy and its displacement. Subsequently, the element mass matrix and damping matrix of the bracing suspension and transmission line, as well as the element nodal load vector obtained from wind load equivalence are given. Then, based on the nonlinear finite element theory, the nonlinear dynamic equation of wind-induced vibration is established for the tension suspension-braced transmission structure and solved by Newmark-β method combined with Newton-Raphson iterative method. Finally, the two-span tension suspension-braced transmission structure is selected as an example, and the wind-induced nonlinear vibration is analyzed through the proposed model. The results show that: 1) the proposed model has high computational accuracy and efficiency. 2) The low order natural frequency of the suspension-braced conductor part is lower than that of the suspension-braced ground line part. 3) Transmission line displacement response of the structure is greatly affected by wind load. 4) Wind speed and wind direction angle have significant effects on the lateral displacement of transmission line and the suspension tension.
  • YANG Lijun1,CHEN Kong2,CHEN Wei3
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 79-87.
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    Based on the assumption of the improved Reddy type third-order deformation theory (TSDT) with seven degrees of freedom variables, the static linear bending and natural vibration modes of functionally graded graphene-reinforced composite (FG-GRC) plate structures are studied by using the meshless method of stabilized moving least-square approximation (SMLS). The effective Young's modulus of the material is estimated by Halpin-Tsai model, and the effective mass density and Poisson's ratio are determined by the rule of mixture. The meshless governing equations of linear bending and natural frequency of FG-GRC plates are derived by using the principle of minimum potential energy and Hamilton principle, respectively. Since the shape function based on SMLS does not satisfy the Kronecker condition, the complete transformation method is used to deal with the essential boundary conditions. Firstly, the SMLS discrete model of FG-GRC plate based on TSDT is introduced. Then, the convergence and accuracy of this method are tested by comparing with the existing results. Finally, the effects of the distribution mode of graphene sheets (GPLs), weight fraction, geometric parameters, total number of layers and boundary conditions on the bending and mode of FG-GRC plate structure are numerically analyzed.
  • YU Yang1,2,ZHANG Penghui1,2,CHENG Siyuan1,2,ZHANG Wenhao1,2,YU Jianxing1,2
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 88-96.
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    The South China Sea is rich in oil and gas resources, and semi-submersible platform often face the major danger of mooring failure when working in this area. In this paper, a semi-submersible platform equipped with catenary mooring system and DP-3 dynamic positioning system is taken as the research object, and study the motion performance of semi-submersible platform before and after mooring failure by using the software AQWA. At the same time, drawing help from the secondary development function of the software AQWA, model-free adaptive control is used as the control theory of dynamic positioning system to study the motion performance recovery of semi-submersible platform after mooring failure. Numerical simulation results show that the semi-submersible platform using model-free adaptive control as the dynamic positioning system control theory can recover the motion performance well after mooring failure and reduce the harm caused by mooring failure effectively. Model-free adaptive control based on partial form dynamic linearization and full form dynamic linearization can recover the motion performance of semi-submersible platform faster than model-free adaptive control based on compact form dynamic linearization.
  • LONG Yao1,2,ZHANG Tongwen1,2,LI Jianping1,2,ZHANG Jiasheng3,XIAO Yuanjie3
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 97-104.
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    Red sandstone coarse-grained soil is fragile, and particle breakage will occur under the repeated action of dynamic load, resulting in obvious post-construction settlement of subgrade. According to the characteristics of particle breakage of red sandstone coarse-grained soil, dynamic load tests under different working conditions were carried out by using a large indoor dynamic triaxial tester, and the relationship between dynamic elastic modulus, dynamic elastic strain and particle size, as well as the relationship between particle breakage rate and the change rate of particle shape coefficient was studied. According to the dynamic breaking characteristics of the materials, a cumulative deformation model considering particle breaking was established and modified. The results show that the larger the particle size, the larger the dynamic elastic strain and the smaller the dynamic elastic modulus. The dynamic elastic strain increases rapidly at first and then tends to be stable. The dynamic elastic modulus decreases with the increase of loading times, and the soil appears strain softening phenomenon. The variation trend of particle shape coefficient is similar to that of particle breakage rate. With the increase of loading times, the shape coefficient value approaches to 1. In addition, the cumulative deformation model includes stress state parameters, physical state parameters and fitting parameters, which can better describe the cumulative deformation trend of coarse-grained red sandstone soil under the condition of particle breakage. According to the inverse computation results of test data, the fitting parameters of the cumulative deformation model are determined, which is convenient to calculate the subgrade deformation in practical engineering application. Due to the difference between the laboratory test and the field condition, the model correction coefficient ψ was proposed, which improves the prediction accuracy. The results of this study can provide theoretical basis and engineering application basis for the design, construction and operation of red sandstone coarse-grained soil subgrade.
  • MENG Xianfeng1,2,HAO Xingyan3,IANG Hui3,WU Songhua1,2,CAO Tiezhi1,2,LUO Meng3,SUN Yongxue1,2
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 105-113.
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    In order to study the influence of impact on the dynamic response of the airport bridge during aircraft landing and taxiing. Taking a runway bridge for the aircraft of class C as the research object and the Boeing 737-800 aircraft as an example, the technology of co-simulation based on finite element software and multi-body dynamics software is applied to the establishment of the aircraft-bridge coupling model for the first time. The whole process of aircraft landing and taxiing on the bridge with different landing attitudes is simulated finely. Based on verifying the accuracy of the aircraft-bridge coupling model, the influence degree and rule of landing mass, sinking speed, pitch angle and roll angle on the bridge dynamic response are systematically discussed and the distribution range of the bridge dynamic factor is defined. The results show that the dynamic factor of bridge is mainly between 1.26 and 1.62 under the impact of aircraft landing. The dynamic factor of bridge increases with the increase of landing mass, sinking speed and roll angle while decreases with the increase of grounding speed and pitch angle. The sinking speed has the most obvious influence. When the sinking speed increases from 1.00 m/s to 3.05 m/s, the dynamic factor increases from 0.98 to 1.87, an increase of 90%. The effect of dynamic load during aircraft landing and taxiing needs to be considered to the design of the runway bridge.
  • CHANG Tingting,SHEN Feng,BAO Siyuan
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 114-122.
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    To investigate the free vibration characteristics of conical rod, analysis models are established based on Euler-Bernoulli beam theory and Timoshenko beam theory respectively. First, in the presented models,series forms including trigonometric basis functions are adopted to express the the displacement function, which can satisfy the boundary condition of the rod. Then the linear equation set about the unknown coefficients is obtained based on the the minimum principle of the energy functional, and several natural frequencies and modes can be worked out by the eigenvalue problems. Similarly, suppose the series forms of the displacement and use the energy function, the solution method is established for conical rod’s vibration problem based on Timoshenko beam theory, and natural frequencies and modes can be obtained. Finally, a transformation formula is presented to transform the natural frequency under the Euler-Bernoulli beam theory and Timoshenko beam theory. The transformation formula is extended to the case of conical rod. The numerical examples analyze the sectional parameters’ influence on the natural frequency of conical rod, and some length parameters of the conical rod are designed based on value of target natural frequency and some restricted conditions. The numerical results show that under the two classical beam theories the presented method is stably converged with high efficiency and good accuracy. The research can provide computational basis for the dynamic characteristics of horn in ultrasonic engineering.
  • LIU Bin1,HUANG Yongfu1,SONG Yanchen2,HAN Qiang2,BAI Hongtao1,DING Kai1
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 123-137.
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    In order to investigate the feasibility of prefabricated assembled piers in high-intensity areas, a new pier-cap joint connected by the inner and outer corrugated pipes is proposed. Two specimens with a scale ratio of 1:3 were designed and fabricated as the internal and external corrugated pipe-connected pier (IOCPCP) and cast-in-place pier (CIP), respectively. By using the method of quasi-static test and finite element numerical simulation, the hysteretic performance, energy dissipation capacity, and curvature of the specimen are analyzed, as well as the failure mode. The test results show that the specimens are all damaged in the plastic hinge zone at the bottom of the pier; the IOCPCP specimen is similar to the CIP in bearing capacity, hysteresis, and energy dissipation, and has better ductility; the IOCPCP specimen can still maintain the bearing capacity of more than 88% of the peak load under the drift ratio of 6%. The parameter analysis accounting for the strength of the longitudinal reinforcement and the length of the internal compensation reinforcement of the pier column was carried out It is considered that the increase in the strength of the pier column longitudinal reinforcement can slightly reduce the plastic hinge area at the bottom of the pier, but requires higher strength of the grout in the peripheral corrugated pipes; when the length of the internal compensation reinforcement is short, double plastic hinges are prone to occur. The test results can provide a reference for the engineering application of prefabricated assembled piers in high-intensity areas.
  • CAO Yinhang1,LIU Gongmin2,HU Zhi1
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 138-145.
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    The transfer matrix method (TMM) is a common calculation method for studying structural vibration, but it suffers from numerical instability in the high-frequency transverse vibration calculation of large-span pipe conveying fluid, which limits its further application. The global transfer matrix method (GTMM) based on the subunit division criterion obtained from the dimensionless results, the hybrid energy transfer matrix method (HETMM) and the transfer matrix method combined with the variable precision algorithm—transfer matrix method (VPA-TMM) can solve this problem. Among these three methods, the GTMM is the most commonly used method to improve the stability of the TMM; the HETMM is extend from the calculation of wave propagation in layered media to the vibration analysis of pipeline system for the first time, the dimension and form of the HETMM calculation matrix do not change with the number of subunits, and the calculation time is the shortest; the VPA-TMM does not require subunit division, it can be seen as a solution to the TMM long-span high-frequency numerical instability problem from the root, but the computation time will increase significantly.
  • WANG Zhisong1,2,WANG Yujie1,YU Bo3,XU Qing3,HE Yong3,LI Zhengliang1,2
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 146-155.
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    The damage of the roof of the UHV converter station usually occurs under wind load. In order to reveal the mechanism of wind-induced failure of the roof, this paper studies the wind pressure characteristics on the roof under three wind fields that includes atmospheric-boundary-layer (ABL) wind, wall-jet-flow and homogeneous turbulence flow. Based on wind tunnel test, the influences of mean-wind-speed profile, wind speed, wind direction and turbulence intensity on the wind pressure are compared. The results show that the negative wind pressure on the windward edge of the roof is largest, and the control wind direction is around 45°. In the wall-jet flow, the fluctuating wind pressure and extreme wind pressure is larger than that in the ABL flow. The wind speed has little influence on the mean and extreme value of the negative wind pressure coefficient on the roof, while the turbulence intensity has great influence on the extreme value of the wind pressure coefficient. It is also found from the result of the test that the extreme wind pressure on the roof of the UHV converter station in ABL flow suggested by the "Roof structure wind load standard" (JGJ/T 481-2019) is safe, while the extreme wind pressure in wall-jet flow is the larger than that suggested by JGJ/T 481-2019, which should pay extra attention in the design.
  • DOU Wei1,ZHAO Dongfang2,ZHANG Hongli2,LIU Shulin2
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 156-165.
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    As the key component of liquid rocket engine propellant delivery system, the operation state of turbopump directly affects the performance of the entire launch system. However, the existing fault diagnosis methods often suffer from the problems of one-sided selection of feature parameters and high computational complexity. Aiming at the above limitations, a lightweight fault diagnosis framework towards turbopump is proposed. The proposed method uses the Hessian local linear embedding algorithm to reduce the dimension of the time-domain, frequency-domain and time-frequency features of the signal, and introduces a lightweight deep learning model MLP-Mixer as the classifier to realize the identification of different fault states. The validity of the proposed method is verified by the test run data of a turbopump. The results show that the proposed method can effectively reduce the computational complexity and improve the diagnostic efficiency while ensuring the diagnostic accuracy.
  • PAN Wei1,2,LI Yuanwen2,3,FENG Daofang1,2,LI Min1,2
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 166-178.
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    Near field acoustic holography (NAH) based on equivalent source method (ESM) is an effective technology for sound source identification. However, for the identification of spatially sparse sound sources, the traditional ESM methods based on L2-norm and L1-norm have some problems, such as insufficient estimation of sound source amplitude or poor stability of the algorithm. Therefore, a sound source recognition method based on constrained L1/2-norm sparse regularization is proposed. This method has the advantages of strong sparsity and strong anti-interference, which can identify the sound sources more accurately than traditional methods. The numerical simulation experiments and ordinary indoor measured experiments demonstrated the validity of the proposed method.
  • YANG Xiaoxin1,2,XIAO Lu1,2,YANG Xiaodong2,LI Qiqi2,GAO Xiaoxin3,JIN Pengcheng4
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 179-186.
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    In order to study the optimization method of dynamic characteristics of multi-stage fixed shaft gear transmission system, a macro parametric dynamic model including gear design parameters and system layout parameters is established by using generalized finite element method with a large mining gearbox as the object. Newmark-β time domain integration method is used to solve the dynamic equations under rated speed conditions. On this basis, an optimization model is established. During the optimization process, a time varying meshing stiffness calculation program in the dynamic equations that can be optimized based on the potential energy method is realized. At the same time, a multi-objective optimization method including system dynamic characteristics and volume optimization is proposed, and compared with the single objective optimization method. The research results can provide a theoretical reference for the macro parameter design of mine gear transmission system.
  • LIU Qingkuan1,2,3,HAN Yuan3,SUN Yifei3,ZHENG Yunfei4
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 187-200.
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    The Reynolds number effect of bridge wind engineering has been a fundamental problem that came from wind tunnel tests. Reynolds number increase accompanied by the development of bridge size, the effect of the difference between wind tunnel Reynolds number and practical bridge Reynolds number are paid more attention. In this paper, Reynolds number effect origin was expounded. The research history of Reynolds number effect is reviewed. Reynolds number effect research development of bridge structure sections including circular section, rectangular section, main girder section etc were summarized, including flow pattern, aerodynamic force and wind-induced vibration change with Reynolds number. Unsolved problems in Reynolds number effect in bridge wind engineering were pointed out. Some recommendations for future research were put forward.
  • XIE Zelong1,YANG Tingfang1,LIU Hanyao2,ZHOU Huikang1,WANG Runpu1,SHAN Songyi1,ZHOU Qianghui1
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 201-207.
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    Noise control of urban transformer is an urgent problem to be solved in power transmission and transformation projects. This paper analyzes the noise spectrum of a 110kV transformer, and obtains the distribution characteristics of the main frequency of transformer noise. A composite sound insulation structure based on multilayer hexagonal membrane-type acoustic metamaterial is designed by taking advantage of the complementarity of sound insulation ability of different types of membrane-type acoustic metamaterials. The sound insulation structure has the characteristics of small volume, strong sound insulation performance and good impact resistance. The finite element method is used to establish the simulation model of the hexagonal membrane-type acoustic metamaterial, and the influence of the thickness and prestress of the film on its sound insulation performance is studied and analyzed. The material is optimized based on the analysis results. On this basis, the finite element simulation model of composite sound insulation structure is established. The simulation results show that the composite sound insulation structure has high sound transmission loss at the main frequency of transformer noise, and the lowest is about 20.4dB, which can block the transmission of transformer noise.
  • YU Xu1,SHAN Zhicheng2,ZHUANG Haiyang3,CHEN Guoxing2
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 208-218.
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    By controlling the intensity and duration of input ground motions, this paper proposes a shaking table test method for pile foundation isolated structure on a variable-stiffness foundation. On this basis, combined with the completed shaking table model tests of isolated structures on different foundations, the influence of the foundation stiffness change on the dynamic characteristics of the pile group foundation of the isolated structure is also analyzed. The results show that the relative stiffness ratio of structure to soil and the strength of the input ground motion significantly affect the moment response of the pile group foundation of the isolated structure. With the increase of the relative stiffness ratio of structure to soil under strong earthquake motion, the upper moment response amplitudes of the middle piles in the pile group foundation of isolated structure grow remarkably, while the lower moment amplitude of the middle pile is relatively small. When the peak acceleration of the input motion and the relative stiffness ratio of structure to soil are greater than a certain limit, the seismic settlement of the pile group foundation increases significantly, and the rotation response of the pile group foundation cap is strong. Meanwhile, the horizontal displacement of grouped pile foundation pile top appears obvious unilateral cumulative horizontal displacement after the main earthquake. It indicates that the pile top of the pile group foundation of the isolated structure tends to occur earthquake damage during the process of foundation stiffness change, while the joint action of the seismic settlement of the pile group foundation and strong rotation reaction of foundation cap may be the main reason for the sharp increase of the pile upper bending moment.
  • ZHANG Yangkai1,2,LU Yiyu1,2,TANG Jiren1,2,LING Yuanfei1,2
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 219-225.
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    Jet pressure characteristics determine its impact capacity, for the booster type pulse water jet transient pressure characteristics are not clear this problem, the use of self-developed booster type pulse water jet pressure acquisition system to carry out experiments to explore the inlet water pressure, oil pressure and nozzle diameter and other parameters on the booster chamber pressure characteristics of the law of influence. The test results show that: as the inlet pressure increases, the peak pressure remains unchanged, the valley pressure increases simultaneously, the frequency increases, and the boost ratio remains unchanged; as the inlet oil pressure increases, the peak pressure gradually increases, the valley pressure remains unchanged, the frequency increases, and the boost ratio remains unchanged; as the nozzle diameter increases, the peak pressure gradually decreases, the valley pressure remains unchanged, the frequency increases, and the boost ratio gradually decreases. Meanwhile, the single cycle instantaneous pressure includes two primary and one secondary pulsations. By modulating the inlet pressure, discontinuous and continuous pulsation pressure characteristics can be obtained.
  • YU Xin,CHEN Ping,HU Yiliang,FU Tong,LI Changze
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 226-233.
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    Aiming at the difficulty of achieving the expected accuracy when measuring the stress of high-strength short bolts by the ultrasonic conventional attenuation method, a method based on ultrasonic scattering attenuation theory and wavelet multiscale decomposition is proposed to measure the stress of bolts. Firstly, a theoretical model of the relationship between ultrasonic attenuation coefficient and stress is derived based on Rayleigh scattering of cubic crystal system materials. Secondly, the wavelet transform is used to obtain the attenuation coefficients of each scale and define the weighted ultrasonic multiscale attenuation coefficients, combine the particle swarm optimization algorithm and gray correlation analysis to determine the optimal scale combination of the attenuation coefficients and their normalized weight coefficients, and establish the ultrasonic multiscale attenuation measurement model of axial stress. Then, using the constructed bolt axial stress ultrasonic measurement system, the axial stress measurement of common bolts was performed, and the feasibility of the method was demonstrated. Finally, the axial stress measurements of high-strength short bolts by the multi-scale attenuation method were compared with transition time method and the traditional attenuation method, and it is verified that the ultrasonic multiscale attenuation method is more suitable for the axial stress measurements of high-strength short bolts.
  • RUAN Shuang1,2,ZHANG Ming1,3,NIE Hong1,2
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 234-243.
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    Aiming at two common aircraft running states, i.e., anti-swing state and control state, a multi-degree-of-freedom vibration mechanical model of landing gear pendulum is established, and the mechanism of the influence of clearance on them is studied. Two different types of vibration mechanical mathematical models of landing gear pendulum with clearance are obtained. Through smoothing of non-smooth system and numerical analysis of multidimensional system. The results show that the shimmy frequency of landing gear will slightly increase under the shimmy reduction condition, and the structural Coulomb friction can weaken the continuous shimmy caused by structural clearance. For the control state, the frequency domain characteristics are analyzed by fast Fourier transform, and it is found that the coupling between the lateral bending and torsion of the strut is serious, and the rigidity between them directly determines the shimmy frequency of the landing gear. When there is a structural gap, the overall frequency of the landing gear will decrease, and eventually the system will gradually tend to a stable limit cycle oscillation state.
  • YANG Mingxing1,2,XIA Yulei2,LIU Qingyun1,2,TANG Guoqing2,ZHENG Jinde1,2
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 244-253.
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    Tendon-sheath transmission system is widely used in robot drive system because of its flexible transmission path and strong flexibility, especially in the bionic design of robot, the combination of lasso drive and artificial muscle is often used to achieve long-distance flexible drive. However, there are obvious nonlinear factors in the lasso drive system, which have a great impact on the overall transmission characteristics of the lasso artificial muscle. In order to explore the influencing factors of the transmission characteristics of artificial muscle of lasso, the static and dynamic models of the transmission system are established based on the Cloulomb friction model and the Lugre friction model theory, and a test bench was built to explore and verify the transmission characteristics of force/displacement. The experimental results are basically consistent with the simulation results. The results show that the total curvature and the friction force are the main factors affecting the transmission efficiency of the lasso, and the large stiffness of the parallel spring and the small stiffness of the series spring are the two main factors leading to the low efficiency of the artificial muscle of the lasso. The research in this paper provides theoretical guidance for the application of artificial muscle of lasso based on Hill model.
  • A Junfeng1, WANG Zhaohui1, XU Kun1, ZHANG Xiangyang2, SONG Chengzhe3
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 254-263.
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    In order to make full use of the advantages of large construction tolerance of socket piers and the self-resetting ability of unbonded prestressed piers after earthquakes, and reduce the on-site prestressed tensioning construction, a hybrid connection prefabricated pier connected by socket connection and factory pretensioned unbonded prestressed reinforcement is proposed. The three-dimensional finite element model of the bridge pier was established by ABAQUS software. The accuracy of the numerical model was verified based on the quasi-static test results. The local damage, hysteretic behavior, skeleton curve, energy dissipation capacity, prestressed tendon tension, joint opening and other behaviors of the bridge pier were analyzed. The results show that the numerical model established in this paper can reproduce the quasi-static results well, and the force-displacement curve of the precast pier with hybrid connection is "flag type"; When the deviation rate of pier top is 5%, only transverse cracks appear on the pier column, without other obvious structural damage; When the socket depth is 0.4D, the cap has slight cracks, and when the socket depth is 0.7D, the cap can provide sufficient uplift resistance without obvious damage; There is stress concentration in the outer steel pipe and steel backing plate.
  • L Duo1, XU Jiahao1, HU Hongwei1, YI Shanchang2, WANG Lei2
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 264-270.
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    Aiming at the propagation velocity deviation of existing ultrasonic nondestructive testing methods in corrosion damage evaluation of reinforced concrete (RC), a monitoring method using coda wave interferometry (CWI) to characterize RC corrosion was proposed. Based on multiple scattering of ultrasonic propagation of concrete, corrosion damage evaluation indexes of CWI were established. A rapid electrochemical experiment was set up to monitor the corrosion process of RC at 0%, 1% and 2% corrosion rates. The relative velocity change "Δv" ⁄"v" and the decorrelation coefficient "K" _"d" were analyzed by stepwise CWI, and the influence of transducer arrangement on the sensitivity of coda corrosion monitoring was explored. The results show that "Δv" ⁄"v" decreases with the corrosion time, while "K" _"d" increases with the corrosion time. The CWI method can effectively monitor the corrosion crack propagation process of RC structure and has good sensitivity. The corrosion cracking of RC structure can be detected by three different arrangements of the transducer: vertical, opposite and same side, and the vertical arrangement is more sensitive to RC corrosion detection.
  • ZHU Can, LIU Yan, YI Zhuangpeng
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 271-279.
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    The submerged floating tunnel (SFT) is a kind of underwater traffic structure with great potential. The accurate acquisition of the frequency and mode of its supporting cables is crucial to identify the dynamic performance of this structure. In this paper, a novel method is proposed to obtain the "dynamic frequency" and "wet mode" of the supporting cables under the tube motion. Four types of mechanical models are established by equating the cable as a beam or string, taking into accounts the bending stiffness, wet-weight and other factors of the cables. On the premise of quasi-static treatment of the moving SFT and determination of the basic parameters of the structure by the principle that the top tension of the supporting cable is equal to the net buoyancy within the support range of the cable during static equilibrium, the distribution law of the dynamic frequency and wet mode of the cable during the vertical periodic motion of tube is studied. The corresponding relationships, as well as the parameter sensitive interval, between the dynamic frequency band of the cable and its upper/lower limits and the tube’s buoyancy weight ratio (BWR), the cable’s inclination angle, the cable’s vertical height and the amplitude of the tube motion are determined. The sensitivities of the wet mode to the span effect of wet-weight, the vertical height and other factors are obtained. This method provides a new treatment idea for further in-depth research on the frequency locking of the vortex-induced vibration and parametric vibration for the cable of SFT.
  • LIU Qingyun1, LIU Kangren1, ZHANG Hongyi1, LIU Tao1,2
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 280-290.
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    Based on the isogeometric analysis method and a simple first-order shear deformation theory (S-FSDT) with only four degrees of freedom per node, the numerical analysis model of piezoelectric integrated graphene platelets reinforced functionally graded porous (P-GPLs-FGP) plates is established. Firstly, the effective material properties of graphene platelets reinforced functionally graded porous plates are determined by using the Halpin-Tsai micromechanical model, the closed cell theory under Gaussian random field and the rule of mixture. Then, the governing equations of P-GPLs-FGP plates are derived based on the isogeometric analysis method, S-FSDT and Hamilton’s principle. The accuracy and effectiveness of developed model are demonstrated through numerical experiment with comparison. Finally, the effects of porosity distribution types, porosity coefficient, graphene platelets distribution patterns, graphene platelets weight fraction, boundary conditions and width-thickness ratio on natural frequencies and static bending response of P-GPLs-FGP plates under electro-mechanical loads are analyzed. The results show that the stiffness of the plates is inversely proportional to the porosity coefficient and can be effectively enhanced by adding a small amount of GPLs into the matrix material. Compared with other considered combinations, the plates with PD-S and GPL-S possess the highest stiffness.
  • DING Yuan, SHI Kaiyao, ZHENG Ling
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 291-298.
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    In recent years, embedded acoustic black holes (ABH) have shown extremely broad application prospects in the fields of structural vibration and noise reduction, sound wave control, and energy recovery with their excellent performance. However, the weakening of local structural strength will affect their engineering practicability. In this paper, a dish-shaped acoustic black hole (DABH) structure is proposed and attached to the main structure to achieve broadband vibration suppression of the main structure. Under the framework of Rayleigh-Ritz method, a gaussian function is selected as the basis function, the distribution of the gaussian function is determined according to the shape of the dish-shaped acoustic black hole, the singularization of the mass matrix and the stiffness matrix is avoided, and the semi-analytical analysis model of the coupling system is established. By comparing with the finite element modal analysis results, the correctness of the semi-analytical modeling method is verified. The influence of the structural parameters of the dish-shape acoustic black hole (DABH) and the connection position on the vibration response characteristics of the main structure are investigated. The ABH effect and the coupling effect with the main structure are analyzed, and the mechanism of broadband tuning and vibration are revealed. It demonstrates the application of ABH in broadband vibration control.
  • NIE Haomiao, CHE Chidong
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 299-305.
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    For many fault diagnosis methods based on vibration signals, the diagnosis is not comprehensive under different loads. A fault diagnosis method based on power spectral density (PSD) and support vector machine (SVM) is proposed.In this method, the vibration signal power is processed by moving average filter (MAF), and the power spectral density (PSD) of the normalized signal of each period in the sample are calculated, and then the kernel method SVM is used for feature classification, so as to realize fault diagnosis. After the actual diesel engine test, the fault recognition rate of this method under different loads reaches 96.72%, and it can effectively identify the faults of the diesel engine intake and exhaust valve gap increase under different loads.
  • GAO Shan1,2, SHI Yao1,2, PAN Guang1,2
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 306-314.
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    During the process of high-speed vehicle exiting-water, its shoulder attached to cavitation across the free liquid surface collapse phenomenon, generating huge impact load, seriously affecting the vehicle exiting-water posture and structural safety. To investigate the evolution of the cavitation flow field details and the collapse load characteristics of the vehicle exiting-water process, this paper adopts the improved delayed detached eddy simulation model. The results show that: the collapse of the vehicle attached to the cavitation during exiting-water process occurs from top to bottom, and at the end of the collapse shrinks to a smaller isolated bubble, the collapse of the resulting high-speed jet impact on the surface of the structure. During the exiting-water process, the counter-rotating vortex pairs near the water surface led to the rapid collapse of the attached cavitation, and the development of the wall vortex structure represented by the hairpin vortex was obviously inhibited by the attached cavitation. The isolated bubble collapse generates a huge impact pressure peak, which causes great damage to the structural safety of the vehicle; However, the bubble collapse behavior on the face flow of the vehicle lead to the appearance of larger pressure peaks.
  • LIU Yating1, DUAN Jingbo1,2, XU Buqing1,2, GAO Yihang3,4
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 315-322.
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    The nonlinear aerothermoelastic behavior of composite panels with transient aerodynamic heating temperature effect was investigated. For the aerothermal model, the aerodynamic heat flux was obtained using the Eckert reference temperature method and the two-dimensional transient temperature field including the in-plane and through-thickness directions of the panel was calculated by the finite difference method. For the aeroelastic model, the Von Karman assumption was used to describe the large-deflection deformation of the composite wall plate, and the first-order piston theory was used to calculate the supersonic aerodynamic force. After the verification of the proposed method, the transient temperature response and aeroelastic limit cycle oscillation (LCO) response of composite panels considering the transient effect of aerodynamic heating were first presented, and compared with the aeroelastic LCO response of the panel in the steady-state temperature field. Moreover, the influences of the shock wave, incoming flow pressure, heat transfer coefficient and initial interference force on the supersonic aerothermoelastic LCO response and transient temperature field of composite panels considering the transient aerodynamic heating temperature effect were discussed.
  • FAN Xing, LI Xiaopeng, PENG Jianwen, LIU Bingfei
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 323-333.
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    Aiming at the pendulum vibration problem of power transmission line inspection robots (PTLIRs) in the field transmission line environment under the influence of natural wind, this paper proposes a pendulum vibration suppression strategy by installing a pendulum dynamic vibration absorber (DVA) in the variable center of gravity box of PTLIR. Firstly, the structural characteristics of the power transmission line system (PTL) and the PTLIR equipped with pendulum DVA are described. The wind disturbance model is established based on the Davenport wind velocity spectrum and the power transmission line system characteristics. The influence of the robot walking on the transmission line is analyzed, the simplified dynamic model of the robot swing under the influence of wind disturbance is established, and the response of the robot under the influence of wind disturbance before vibration suppression is given. Furthermore, based on the Lagrange equation, the dynamic model of the PTLIR with DVA is established, and the parameters of the DVA are designed. The effectiveness of the proposed vibration suppression strategy is verified by simulating the wind vibration response of the robot under different wind speeds. Finally, based on the prototype of the PTLIR with the improved structure, the indoor wind disturbance experiment is carried out. The results show that: the proposed vibration suppression strategy of DVA would be useful for restraining the robot's fuselage swing and improving the working stability. The research process of this paper is meaningful for the stability optimization of other pendulum structure equipment.
  • HUANG Jiacheng1,XIAO Xinbiao1,WANG Qi1,DU Xing2,ZHOU Shunyuan1,DU Yelin3
    JOURNAL OF VIBRATION AND SHOCK. 2024, 43(2): 334-342.
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    In order to study the influence of traction transformer on the interior noise of municipal train. In this thesis, the multi-physical field coupling model of electromagnetic field-structural force field-pressure sound field of traction transformer and the simulation model of vehicle interior noise are established. The effectiveness of the traction transformer and the car body simulation model is verified by the transformer radiation test and the interior noise test respectively. The noise simulation model of traction transformer considers the anisotropy of core material and the nonlinearity of magnetostrictive. The interior noise simulation model considers the structural characteristics of the car body. In order to reduce the influence of transformer on vehicle interior noise. According to the radiation noise generation mechanism and field test results of traction transformer, noise reduction measures are proposed from two aspects of transformer structure and electromagnetic parameters. Based on the established transformer and vehicle noise simulation model, the noise reduction measures are simulated and analyzed. The results show that the noise reduction effect is the most obvious when the core stiffness increases by 60% and the magnetic flux density decreases by 10%. The total noise in the vehicle is reduced by 8.2 dBA and 4.4 dBA respectively. Reducing the core flux density has an inhibitory effect on noise in the range of 50 ~ 5000 Hz. The noise reduction scheme of 80 % and 60 % increase of vertical clamp stiffness and transverse clamp stiffness can also effectively reduce the total radiated noise of traction transformer, but it can only suppress the noise in a certain frequency range.