15 April 2021, Volume 40 Issue 7
    

  • Select all
    |
  • YIN Yihe1,2,3, HAN Zhiyu4, ZHANG Zhiying1
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 1-8.
    Abstract ( 345 ) Download PDF ( 136 )   Knowledge map   Save
    Damping system represents the overall energy consumption characteristics of a structure system. The identification of damping system type is the premise of choosing structural dynamic analysis method, and is also the basis to ensure the correctness of structural aseismic analysis results. The identification of soil-structure interaction(SSI) damping system under dynamic action is usually based on material properties, it is lack of basic scientific research.Here, based on the most basic judging method of damping system, by means of shaking table model tests of large-scale SSI system, the consistency of dynamic characteristics of different parts of SSI system under dynamic action and the continuity of the system’s motion state at solid-structure interface were examined. SSI damping system and its change law under different dynamic actions were studied. The results showed that under certain conditions, SSI system can reveal obvious classical energy-dissipating characteristics, and be expressed as an approximate classical damping system.
  • WANG Fei1, SONG Zhiqiang1, LIU Yunhe1, ZHANG Jianfeng2
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 9-18.
    Abstract ( 174 ) Download PDF ( )   Knowledge map   Save
    Aiming at problems of oblique incidence being seldom considered in near-fault ground motion input and existing different free-field construction methods, the accuracy of different free-field construction methods and their influences on seismic response of ground hydropower house were studied. Firstly, the total wave field was decomposed into ingoing and outgoing fields. 3 kinds of free fields on each foundation border surface were analyzed based on the principle of wave field superposition. The equivalent nodal load formula corresponding to each border surface free field was derived, and the oblique incidence input of plane SV wave was realized combining with boundary conditions.Free-field of the whole foundation under 3 oblique incidences and its calculation accuracy relative to the analytical solution were analyzed. It was shown that when outgoing fields of bottom and right border of foundation are not considered, the calculation error is large;when they are considered, the calculation error is very small, and the maximum error is only -3.8%.Secondly, effects of pulse type and non-pulse ground motions on seismic response of the hydropower house under 3 kinds of free field construction methods were studied. The results showed that the total input energy and damage energy dissipation of the powerhouse have larger increase without considering outgoing fields of bottom and right border of foundation to cause extensive damage of draft tube structure at lower part of the power house and obvious change of the proportion of various energy in the total input energy;under the same free field construction method, the damage ability of pulse type ground motion to the powerhouse is stronger, so attention should be paid to the aseismic design of the powerhouse near the fault area.
  • GE Yue, WANG Hongbo, GONG Min, LUO Bo, ZHAO Junfeng, GAO Feng
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 19-28.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Here, aiming at influences of flexible effect on separation process of a satellite cabin shell, a rigid-flexible coupled dynamic model for horizontal throwing separation of a composite satellite cabin shell was established based on the flexible multi-body dynamic method. The thrust-displacement relationship of a thruster was used to realize the thrust equivalence of the thruster from ground tests to arbitrary conditions. Simulation and contrastive analysis for the flexible body model and the rigid body model were performed. The results showed that elastic deformation of the shell is dominated by the second-order “breathing motion” mode to absorb about 15% of work done by the thruster, and the separation speed decreases; the respiratory motion at the lower corner point of the separation surface is the most severe, and the influence of the first time inward breathing movement of the half hood on the inner envelope is the greatest; the flexibility effect can also affect the thrust action time history of the thruster. Satellite cabin separation ground tests were conducted. A high-speed photography was used to measure the half hood’s motion to contrastively verify the correctness of the simulation method. It was shown that the simulation error is less than 13%; the study results are helpful to ensure the effectiveness of the separation scheme, release the design margin of the satellite cabin inner envelope space, and provide a reference for separation optimization design.
  • QIN Yezhi, WANG Ying, WANG Zhikai, YAO Xiongliang
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 29-36.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to study damage characteristics of fixed single-layer square steel plate under near-field underwater explosion of small equivalent column charge, the high-precision Runge-Kutta discontinuous Galerkin(RKDG)method was used to solve the column charge near-field underwater explosion load, and the solution was compared with that obtained using the empirical formula of underwater explosion, both of them agreed well each other.The calculated explosion load was input into the LS-DYNA nonlinear finite element solver,damage characteristics of the fixed single-layer square steel plate were obtained, they were compared with test results to verify the accuracy of the model. It was shown that the Runge-Kutta discontinuous Galerkin-finite element method(RKDG-FEM) coupled computation model can accurately simulate damage response characteristics of fixed singer-layer square steel plate under column charge near-field underwater explosion.Then, damage modes of the fixed single-layer square steel plate with thickness of 4 mm andcharge of 5-30 g as well thickness of 3-8 mm and ascharge of 20 g werestudied, respectively. The results showed that damage modes of fixed single-layer square steel plate are mainly plastic deformation, petal type break and plug type round break;the break size calculation formula considering charge weight and plate thickness is fitted;the study results can provide a reference for the damage research of single-layer plate under small equivalent column charge near-field underwater explosion.
  • LIU Xiaobing1,2,3, WU Qianyun3, JIANG Huimin3, ZHAO Huitao3, YANG Qun1,2,3
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 37-44.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Through wind tunnel tests of rigid model pressure measurement, aerodynamic force interference effects of tandem cylinders with different numbers and spacings in uniform flow field were studied. It was shown that the ratio  L/D of the center distance between adjacent cylinders L to cylinder diameter D changes from 1.2-12.0; the number of cylinders varies from 1-4; Reynolds number is 3.4 × 104. Test results showed that the critical spacing ratio (L/D)cr for flow state switching of tandem cylinders is 3.5-4; near the critical spacing, time average drag coefficient and fluctuating lift coefficient of the first two cylinders increase sharply, while the others drop sharply, and Strouhal number of each cylinder rises abruptly; the effect of aerodynamic force interference on time average drag coefficient and Strouhal number of tandem cylinders mainly reveals a reduction effect; effects of increase in the number of rear interference cylinders on the aerodynamic force of the first upstream cylinder can be ignored, while increase in the number of front interference cylinders has a significant impact on aerodynamic force of the last downstream cylinder.
  • YANG Yang1, WU Xiaoli1, XU Yuqian2, YANG Yiren1, CAO Dengqing2
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 45-52.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To investigate the geometric nonlinearity of a rotor in whirling with large amplitude, Hamilton principle was utilized to set up its equivalent dynamic model with both equivalent linear stiffness and equivalent nonlinear one revealing its geometrically nonlinear characteristics. Then, the misalignment fault of gear coupling and the unbalance fault of rotating disc were considered, and dynamic behavior of the geometrically nonlinear rotor system under misalignment-unbalance coupled fault was further studied. Finally, by comparing the response difference between linear rotor and nonlinear rotor, potential influences of rotor geometric nonlinearity on vibration characteristics of the system were analyzed, and effects of parameters, such as, misalignment degree of coupling, rotor radius and rotor length were discussed.
  • LIU Tao, ZHANG Qiang, LIU Wenguang, YUE Sheng
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 53-61.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Here, an adaptive variable stiffness seismic isolation device was developed based on mechanical performance features of negative stiffness system. Based on structure and deformation mechanism of the device, its theoretical mechanical model was proposed and its simplified three-stage variable stiffness model was established. The vertical compression quasi-static test results of the device showed that the three-stage stiffness of the theoretical mechanical model and that of the test mechanical model are basically consistent, the three-stage stiffness can effectively simulate the device’s variable stiffness mechanical characteristics. Combining the adaptive variable stiffness device and lead rubber bearing, the mechanical model of a variable stiffness seismic isolation system was deduced. The seismic response analysis of a local library showed that the new device can meet aseismic performance design requirements with different levels, reduce acceleration response of the isolated structure, avoid excessive displacement of isolation layer, and effectively improve stability and seismic isolation efficiency of the whole system.
  • LI Qi1, LI Bin1,2, MENG Xiaojun1, TANG Xiaowei2
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 62-67.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The method of time step automatic adjustment proposed in “The time step automatic adjustment method with synchronous change of load” is a beneficial attempt in the field of prior error evaluation, it is called the apriori time adaptive method (ATAM). In process of using ATAM, it is generally difficult to obtain analytical solutions. Therefore, it is impossible to evaluate the improvement degree of calculation efficiency after applying ATAM in numerical computing programs. Here, a method to solve this problem was proposed and verified. Then, a simplified evaluation algorithm was further proposed, and a calculation formula to estimate the improvement degree of computing efficiency was deduced. It was shown that according to this calculation formula, the minimum time step is not needed to be substituted into the original numerical program for improving the computing efficiency; using the new evaluation algorithm can directly improve the computing efficiency and save a lot of computing costs; the practicability and effectiveness of the new evaluation algorithm are verified.
  • ZENG Falin1, LIU Yachen2, HU Feng2
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 68-74.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    As an important part of studying influence of auto body vibration on its interior noise, the analysis of auto body panel contribution is usually realized using acoustic transfer vector (ATV) simulation. Here, in order to further explore effects of vehicle body vibration on its interior speech intelligibility, objective parameters of speech intelligibility were compared with subjective evaluation scores to take the speech intelligibility index (SII) under unsteady acceleration condition as the evaluation index, and ATV simulation method was used to find out the panel having the maximum impact on speech intelligibility. The analysis results showed that the body roof panel has the maximum effect on speech intelligibility. Aiming at the analysis results, the method of combining genetic algorithm and ATV inverse operation simulation was used to perform targeted body roof damping and verify it. The results showed that the optimized design based on contribution of speech intelligibility of body panel can effectively improve the interior speech clarity under the unsteady full throttle acceleration condition, and improve the interior sound quality.
  • ZHU Fucheng1, GUO Feng2
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 75-80.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Stochastic resonance (SR) phenomena in a fractional order linear oscillator with time-delayed kernel function and random characteristic frequency were investigated. Base on the linear system theory, using Laplace transformation, the analytical expression for the system output amplitude (SOA) of a fractional order oscillator was derived. It was shown that SOA is a periodic function of delayed-time of the kernel function; SR phenomena appear in relation curves of SOA versus noise correlation rate, SOA versus noise amplitude, and SOA versus fractional dimension, respectively. The non-monotonous dependence of SOA on system parameters and noise steady-state probability was analyzed.
  • ZHANG Wenzhuo, LI Ming, HAN Yongchao
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 81-88.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Considering factors, such as, base motion with low frequency and large swing and nonlinear oil film moments caused by tilting of rotor in bearings, the dynamic model of a sliding bearing-rotor system was established using Lagrange equation. Then, effects of base motion on nonlinear dynamic characteristics of the system were studied using the numerical method. The results showed that after the rotor system loses its stability for the first time, its dynamic bifurcation characteristics have two-branch of upper and lower complex quasi-periodic motions, and the rotating speed during the system losing its stability for the second time rises; when the rotor speed is higher, the rotor’s vibration amplitude increases sharply, and it reaches inner wall of bearing bush in quasi-periodic stage and can’t transit to chaotic state; effects of swing frequency and amplitude variation of base motion on dynamic characteristics of the system were discussed; the above conclusions are helpful to understand motion laws of sliding bearing-rotor systems with low frequency and large swing base motion.
  • CHEN Taicong, HONG Huihuang
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 89-94.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In health monitoring practice of bridge structures, using structural dynamic responses to identify bridge-site’s ground motion is very important for structural safety evaluation. Here, firstly, according to characteristics of bridge site, a non-stationary random process model was chosen to describe ground motion, and the corresponding variance function was derived. Then, a mathematical model was established for the ground motion identification problem. Based on the principle of maximum likelihood estimation, a progressive identification algorithm of real ground motion time history was deduced, in which the sensitivity of acceleration response corresponded to the discretized impulse response function. Taking a 3-span rigid frame bridge subjected to lateral earthquake as a numerical example, the identification effect of the proposed method was examined from two aspects of number of sensors and influence of observation noise. The results showed that the proposed identification method does not require a large number of sensors and has good anti-noise performance. Finally, shaking table tests of structural model was conducted to further verify the effectiveness of the proposed method.
  • JIANG Hancheng, WEI Jing, ZHANG Aiqiang, ZHOU Renhongyi
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 95-104.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The dynamic model of a gear-rotor-casing coupled system considering shafting and casing flexibility was established based on the super element method and node finite element method.Meshing relations of various types of gear pairs were derived.Taking the main reducer of a helicopter as the study object, vibration response tests were used to verify the effectiveness of the model.From the perspective of vibration energy, the multi-stage gear excitation phenomenon generated in the system model when gear pair was taken as a vibration excitation source and transmission characteristics of vibration energy when gear pair was used as a transmission structure were studied under two conditions of flexible casing involving coupling and uncoupling. The results showed that after casing involving coupling, the extreme point number of vibration energy contribution rates of gears of various stages decreases, the vibration energy contribution of gear excitation source near the target point to this point generally increases, whilethat of the non-adjacent gear excitation source to the target point generally decreases; increase in gear meshing stiffness and meshing damping ratio can increase the contribution of gear pairs to vibration energy; increase in meshing error can reduce the transmission capacity of vibration energy, while the coupled flexible casing can enlarge effects of gear meshing characteristics on gear pairs’ vibration energy transmission capacity.
  • GUO Pengcheng1, ZHENG Xiaobo1, ZHANG Hao1, GOU Dongming1,2
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 105-111.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    There is a shared pipe segment diversion system in a pumped storage power station with one pipe and multi-unit, hydraulic coupling interaction of the shared pipe segment is the key to the system dynamic modeling of pumped storage power station. Here, the coupling action of hydraulic system of the shared pipe segment was considered, and it was decomposed into several single variable functions only depending on the flow rate of each sub-pipe segment. Combining with dynamic characteristics of a pump-water turbine set, the non-linear dynamic model of a pumped storage power station with one pipe and multi-unit was established. When two units running in parallel under the rated condition, numerical simulation was used to explore effects of sudden full load rejection of one unit on dynamic characteristics of unit flow rate, water head and output inside each branch pipe under different guide blade closing rules and the other unit with speeder PID control. The simulation results showed that there is a positive correlation between dynamic responses of normal operation unit output and flow rate, dynamic response of unit water head has a negative correlation to its flow rate and output, and their fluctuation periods are close to each other; dynamic responses of water head and flow rate of the unit with sudden load rejection are closely related to  closing rules of guide blade; fluctuation degree of water head of the unit with sudden load rejection is always higher than that of normal operation unit, and their fluctuation periods are similar; the study results provide a theoretical reference for exploring transient dynamic modeling and stability control of pumped storage power station systems with one tube and multi-unit.
  • WU Shuaifeng, CAI Hong, YAN Jun, XIAO Jianzhang, WEI Ran
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 112-118.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on large-scale dynamic compaction tests of high fill earth rock mixture in Chengde airport, by means of laser scanning and 3D modeling, it was shown that the exponential attenuation relationship between single click tamping settlement and tamping times is obtained, and it is divided into rapid subsidence section and gentle development section, then the 3-parameter dynamic compaction settlement model is established; according to parameter evolution law, α is defined as the initial tamping settlement factor parameter, β is the site factor parameter of the area to be reinforced, and δ is the stable tamping settlement parameter. The results showed that the established model has good applicability to cover gravel soil, sandy soil, clay, silt and other types of foundation reinforcement, and the correlation law between model parameters and site conditions is obtained; the application of the model can guide the design of dynamic compaction, assist the detection of construction effect, and have stronger practical value in engineering.
  • WEI Chengxun1, ZHOU Daocheng2, ZHANG Jian3, XUE Sisi2
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 119-125.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at the study method of wave action dynamic model test of bridge tower structure of a cross sea bridge, the similarity method and model design method for dynamic model test of bridge tower structure were proposed by analyzing the similarity principle of dynamic model test of underwater structure. Then, a dynamic model of tower structure of a large-scale sea-crossing cable-stayed bridge was designed and manufactured, and structural dynamic characteristics tests and wave action dynamic response tests were conducted with the test model. Dynamic model test results showed that the structure main natural frequency measured with tests is close to that designed for the original structure, the test model structure can better simulate natural vibration characteristics of the original structure; base forces and dynamic responses of the model structure agree well with the corresponding numerical results of the original structure; the test results verify the feasibility of the proposed model test similarity method and model design method, they have application and reference significance for the hydro-elastic model test research of cross sea bridge structure.
  • ZHU Jingbao1,2, SONG Jindong1,2, LI Shanyou1,2
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 126-134.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to more accurately estimate earthquake magnitude, using Japanese K-Net strong earthquake data within 3 seconds after P-wave triggering, 12 P-wave characteristic parameters including 4 kinds of amplitude parameter, period one, energy one and derivative one were selected as input to construct the prediction model of earthquake magnitude based on support vector machine for earthquake magnitude estimation (SVM-M). Results showed that compared with the traditional earthquake magnitude estimation “τc method” and “Pd method”, the prediction error of the established SVM-M model is obviously reduced and not affected by variation of epicentral distance, and the overestimation of small earthquake is obviously improved. The case analysis results of main earthquake of 2016 Kumamoto earthquake (Mj7.3) in Japan and 2008 Wenchuan earthquake (Ms 8.0) in China showed that the 3-second time window can’t match the whole process of focal rupture, and the seismic magnitude is underestimated to a certain extent, but what happening can be determined as a large earthquake event within the short time window after P-wave triggering; the established SVM-M model can be used to rapidly estimate the seismic magnitude for earthquake early warning.
  • ZHANG Desheng1, GU Qi1, ZHOU Qiang1, HUANG Yadong1, SHI Weidong2
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 135-141.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to analyze applicability of the transient water lift theoretical model and unsteady cavitation process in start-up process of a mixed flow pump, high-speed photography and pressure measurement tests were conducted to investigate cavitation characteristics in blade tip region of the mixed flow pump under different working conditions of cavitation number and flow rate. The test results showed that the existing theoretical model can be applied to the start-up process of mixed flow pump, and the correctness of test results is verified; in start-up process, cavitation occurs firstly in blade tip region; when start-up is completed, the blade tip cavitation region can be divided into two parts, one is a triangular cavitation cloud cluster appearing in blade tip region, the other is a blowing vortex cavitation; under conditions with the same flow rate, with decrease in cavitation number, vertical cavitation vortex can appear and develop in start-up process; under conditions with the same cavitation number, with decrease in flow rate, vertical cavitation vortex occurring delays and cavitation area shrinks.
  • LIU Guangtong1, QU Di2, GUO Tao1, HE Tian2, XU Kai1
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 142-147.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    With development of aerospace science and technology and increasing in performance requirements, the reliability of satellites is required to be higher and higher, and stricter requirements for vibration during transportation to meet are also needed to make the current vibration reduction system be difficult to satisfy future transportation requirements. Here, aiming at this situation, a satellite packaging transportation vibration reduction system was designed based on parallel air spring structure, and its vibration characteristics were analyzed. Firstly, a parallel air spring vibration reduction system scheme was proposed according to structure and vibration reduction requirements of satellite transport box. Then, based on the measured parameters, the multi-body dynamic simulation model of the parallel air spring vibration reduction system was established, and the feasibility of the proposed scheme was verified. The vibration reduction efficiency and safety of the system under different transportation conditions were further studied. Finally, the vibration reduction system was constructed to perform real vehicle transportation tests under different working conditions. The results showed that the vibration reduction system based on air spring parallel structure has better vibration reduction efficiency in actual vehicle transportation and can ensure the safety of the equipment during transportation; the study results can provide a reference for designing large precision equipment transportation’s vibration reduction system.
  • GAO Jianzheng, WU Haijun, JIANG Weikang
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 148-153.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The vortex shedding noise of rotating blade is a kind of typical directional sound source. However, the directivity of vortex shedding noise can’t be measured accurately due to blade rotating. Here, two planar arrays were used to study the acoustic imaging of sound source in two directions of parallel and vertical to the rotating surface of blade. In tests, different blade rotation azimuth positions were selected to perform beamforming acoustic imaging of vortex shedding aerodynamic noise. The directivity of vortex shedding noise was verified by comparing acoustic imaging results under different blade azimuth angles and array directions, and effects of different blade rotation azimuth angles on vortex shedding noise were analyzed. The test results verified the feasibility and effectiveness of the dual-array acoustic imaging measurement scheme. The comparison of imaging results showed that the rotating aerodynamic noise source of NACA0012 blade at 2.5 kHz is directional.
  • WANG Tao, LIU Degui, ZHANG Xingbiao
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 154-163.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Taking a real cable-stayed bridge as the study object, effects of cable-beam related vibration on cable fatigue reliability of the bridge under wind and train action were analyzed. A 3-D precision finite element (FEM) model of a long span railway cable-stayed bridge was established by using the existing finite element dynamic analysis program, vibration responses of the full bridge under wind and train action were calculated, and characteristics of cable-beam related vibration of the full bridge were analyzed. The probability model of train traffic load was established, and the wind load probability model of the bridge was established according to wind speed statistical data at the bridge position, and the stress spectrum of the cable was calculated. Based on the damage theory, the fatigue reliability analysis of cable under wind and train dynamic action was performed by using Monte Carlo method. The results showed that in daily operation state of the bridge, cable-beam related vibration under action of wind and train can’t cause cable resonance, and cable-beam related vibration is the main reason for the decline of cable fatigue reliability; for the fatigue failure probability of cable under long-term dynamic load, wind field action accounts for a smaller proportion, while train action takes a larger proportion; cable force of each cable in finished state affects cable stress amplitude under train action, and further affects cable fatigue reliability of the bridge under long-term dynamic action.
  • LIU Xinyun1, MA Jisheng1, HOU Jian2
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 164-170.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Because the structure of naval gun test projectile is different from that of the real projectile, its rebound speed is excessively high when loading in bore to cause the fracture of related parts and latch failure. Here, a differential clay buffer was designed to absorb excessive kinetic energy to ensure the reliability of the test projectile. In order to evaluate the buffering efficiency of differential mastic buffer on the test projectile and analyze the projectile loading motion law, a simulation analysis method combining buffer fluid numerical analysis with computational fluid dynamics (CFD) and multi-body dynamic analysis (MBD) was proposed. The computation results showed that the proposed method can accurately compute and predict the buffer efficiency of the buffer, and the buffer meets design technical requirements; in process of static pressure, multiple vortices are formed behind piston, while in process of impact, streamline is stable without vortices; the viscous impedance component increases firstly and then decreases with decrease in compression rate; the study can not only provide a theoretical support for application of clay buffer in naval gun test projectile, but also provide a new analysis method for studying clay buffer.
  • XUE Zhijie, LI Qicai, HUANG Shen
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 171-178.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to study aseismic performance of porous butterfly-shaped steel plate shear wall, low cycle cyclic loading tests of 4 full-scale specimens were conducted. On the premise of the waist width ratio of butterfly bar being controlled at 0.4, effects of steel plate thickness and opening rate on hysteretic performance, load-bearing capacity and energy dissipation performance of porous butterfly-shaped steel plate shear wall were studied. The test results showed that porous butterfly-shaped steel plate shear wall has good aseismic performance and is an ideal anti-lateral force component and energy dissipation component; its ultimate failure mode is end tearing of butterfly rod on the outermost side of the steel plate; with increase in thickness of the steel plate wall and decrease in its opening rate, lateral stiffness and load-bearing capacity of specimens increase and their energy consumption increases.
  • LI Wei1,2, HUANG Yan1,3
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 179-187.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to ensure safety of offshore platform, identify and locate its damage in time, the structural health monitoring technology of offshore platform has become an important issue for scholars. Here, for a jacket platform in service, its dynamic responses under different random wave excitations were numerically simulated in health state and damage state, respectively. In the process of damage identification, cross-correlation analyses of dynamic responses of different positions of the platform were performed to extract damage sensitive features. Then the principal component analysis (PCA) method was used to extract principal component from complex data. Finally, the damage index was defined and the damage identification was done. Aiming at the problem of the traditional PCA method’s accuracy for damage identification of some members being not high, a new method of selecting principal components was proposed to improve the traditional PCA method. The results showed that the improved PCA method can effectively improve the accuracy of damage identification to correctly identify structural damage under random wave condition.
  • XU Zidong, WANG Hao, LIANG Ruijun
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 188-192.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Ground motion is a typical nonstationary stochastic process, and its energy time-frequency distribution can be described by evolution spectrum. However, time-frequency coupled characteristics of evolution spectrum limit the simulation efficiency of the classical spectral representation method. Here,in order to improve the efficiency of non-stationary ground motion simulation, and simplify the structural random response analysis under non-stationary earthquake, a decoupling scheme of ground motion evolution spectrum based on non-negative matrix factorization was proposed to simplify the calculation of structural response under non-stationary earthquake as superposition of structural random responses under each uniform modulated excitation. Results showed that the decoupling of the evolution spectrum of ground motion based on non-negative matrix factorization has good accuracy; introducing fast Fourier transformation (FFT) technology improves the simulation efficiency of the classical spectral representation method, the auto-correlation function of simulation samples agrees well with the target value, and the frequency domain analysis of structure random responses under the action of nonstationary earthquake is simplified.
  • LI Chuangdi1, CHANG Mingjing1, BAI Dalian2, WANG Bowen1
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 193-201.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to establish the aseismic dynamic reliability analysis method for practical viscoelastic damper energy dissipation structure and damper system with braces, a general analytical solution to responses of a practical viscoelastic damper energy dissipation isolation system with braces in non-expansive order space under non-uniform and completely non-stationary seismic excitation was proposed. Firstly, the equivalent transformation was made for the practical viscoelastic damper with braces, and the dynamic equation of the isolation structure system was established. Then, the non-orthogonal mode superposition analytical solution to the transient response of the system under arbitrary excitation and non-zero initial conditions was obtained in non-expansive order space. Furthermore, due to the non-stationarity of intensity and frequency of ground motion, the general analytical expressions for non-stationary mean square responses  of the system’s displacements, velocities, damper’s force and force velocity, brace’s displacement and velocity, damper’s displacement and velocity were obtained, and analytical solutions to the system’s responses under the classical uniform and non-uniform modulated non-stationary random earthquake excitation and C-P completely non-stationary ground motion power spectrum model, respectively were obtained. Through comparing frequency response functions of the system’s various responses obtained with the proposed method and those obtained with the direct solving method, the correctness of the proposed method was verified. The proposed method provided a new analysis way for aseismic design and aseismic dynamic reliability analysis of practical viscoelastic damper energy dissipation structure and damper systems with braces.
  • DAI Qiyi1,2, QIN Zhaoye2, CHU Fulei2
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 202-207.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Micro-macro damping characteristics of laminated composite cylindrical shells were studied here. Based on Reissner-Naghdi thin shell theory, the vibration differential equations of a cylindrical shell were derived. In process of separation of variables, Haar wavelet series was used to represent axial mode, and Fourier series was used to represent circumferential mode. The unknown coefficients appearing in integration were solved using boundary conditions to obtain the characteristic equation to be used for analyzing free vibration characteristics of the cylindrical shell. Based on the microscopic damping calculation method and multi-cell model of hybrid materials, the equivalent damping characteristics and equivalent elastic characteristics of single-layer composite material were obtained, and damping characteristics of a composite cylindrical shell were predicted using the complex modulus method. By comparing damping prediction results with those published in other literature, the effectiveness of the proposed method was verified. Effects of fiber content, circumferential wave number, laminated mode and geometric parameters on damping characteristics of composite cylindrical shell under four typical boundary conditions were further analyzed.
  • XU Xu1, YANG Xiaofeng2, SHEN Yujie2, LI Yue1
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 208-215.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to study effects of time delay on stability of a semi-active suspension system, a 2-DOF semi-active suspension model with time delay was established, and sufficient and necessary conditions to satisfy all delay stability of the system was derived by using the improved all delay stability algebraic criterion according to the stability theory of time delay system, and the range of controllable damping value was obtained. Aiming at semi-active suspension parameters not satisfying the all delay stability condition, the stability switching point analysis method was proposed to solve and obtain the actual stability switching point and its stability interval. The time-domain simulation showed that the generation of time delay does not lead to the deterioration of suspension performance under the all delay stability condition; under the condition of non-all delay stability, the performance of suspension drops with increase in time delay and worsens sharply when time delay exceeds the stability switching point.
  • WANG Jinjin1, LI Zhigang1, YANG Haifeng1, LIU Fu2
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 216-221.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Here, the bird impact problem of multispectral zinc sulfide (ZnS) optical glass material used in aircraft was investigated. Firstly, dynamic compressive tests were conducted on multispectral ZnS glass at high-medium strain rate to obtain its material properties. Secondly, a bird body was modeled using the smoothed particle hydrodynamics (SPH) method, and Gruneisen state equation was introduced to define the bird body constitutive model. The established bird body model impacting aluminum plate was simulated and verified with tests. The verification results showed that the established bird body model has higher accuracy and can be used for simulation in other impact cases. Finally, a model of bird impact glass plate was established to predict the anti-bird impact performance of multispectral ZnS glass. Simulation results showed that the ultimate strain and failure of ZnS glass are easy to reach at impact position and place of edge constraint; contact force peak value of glass surface decreases with decrease in bird impact angle; the study results can provide a reference for numerical simulation of the bird body SPH method and application of multispectral ZnS glass in aircraft.
  • CHEN Liangliang1,2, ZHU Changsheng3, CHEN Bo4, ZHOU Jiehua2, LI Zhinong1
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 222-230.
    Abstract ( ) Download PDF ( )   Knowledge map   Save

    Stator permanent magnet motor is very suitable for high speed operation due to its advantages of no permanent magnets and windings in rotor, high power density, and high efficiency. However, because of complex geometric configuration of its salient pole rotor, the rotor strength analysis in high speed operation can only be done using numerical methods, such as, the finite element method (FEM). Here, based on the elasticity theory, the analytical analysis model of salient pole rotor strength was established. Firstly, the load distribution of the salient pole rotor was analyzed. Then, based on the plane stress model and the stress function method, analytical solutions to stress and deformation of the salient pole rotor of the stator permanent magnet motor were derived, and the effectiveness of analytical solutions was verified using FEM. Finally, effects of salient pole height and shape on rotor strength were analyzed. The results showed that the calculation results of strength analytical solutions to the salient pole rotor established here agree well with those obtained using FEM in the maximum stress region of the rotor to accurately analyze the maximum stress of the salient pole rotor of the motor; the study results can provide a support for rotor design of stator permanent magnet high-speed motors.

  • YAO Yanping1, ZHANG Bisheng2
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 231-236.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In running process of a belt conveyor, the dynamic tension of conveyor belt propagates in the form of wave along the running direction of belt, and produces longitudinal vibration in process of transmission. The larger longitudinal vibration of belt can affect the distribution of driving force of multiple rollers. Here, Kelvin-Voigt viscoelastic model was taken as the mechanical model of conveyor belt, and the distribution equation of driving force for longitudinal vibration of long-distance belt conveyor was established based on the constitutive equation of conveyor belt. Taking a certain long-distance belt conveyor driven by its head double-drum in Tianjin Port as an example, the driving force variation curve of driving drum and the vibration curve of conveyor belt in start-up process were simulated. The simulation results were compared with test ones. It was shown that for the belt conveyor system driven by its head double-drum, with increase in elastic modulus of conveyor belt, vibration of belt is reduced, and driving force distribution of double-drum drive is closer to the ideal power ratio; the study results can provide a reliable basis for rational selection of conveyor belt, and make the motor work near the design work point to avoid burning the drive motor due to uneven driving force distribution.
  • SHANG Huilin, DONG Zhanghui, LIU Hai, LIU Zhiqun
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 237-243.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on the global bifurcation theory, the mechanism of pull-in instability of a typical electrostatic driven bilateral capacitive micro-resonator was studied. Then, a linear time-delay velocity feedback was introduced into the system’s DC bias voltage to control complex dynamic behavior of the system. By introducing independent parameters, the exact analytical expression of the system’s heteroclinic orbit was obtained. Furthermore, Melnikov method was used to predict heteroclinic bifurcation conditions of the microstructure to obtain its AC voltage threshold causing its pull-in instability. It was shown that the numerical results agree well with the theoretical analytical ones to verify the time-delay velocity feedback control being able to effectively suppress pull-in instability, chaos and other complex dynamic behaviors of this kind of bilateral capacitive micro structures; the study results have potential application value for optimal controlling the performance of micro resonators.
  • LIU Haisong, CHEN Haijun, WU Yuxuan, CHEN Jianfeng, YIN Guofu
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 244-252.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To make high-speed counter-current chromatograph’s planetary transmission mechanism run stably, through the analysis of traditional prefabricated balance hole design algorithm and the verification of simulation software Matlab, a modified prefabricated balance hole design algorithm was proposed. The modified prefabricated balance hole design algorithm was applied in the balance hole design of chromatograph planetary mechanism separation column. Combined with residual unbalance of separation column, the balance hole structure of rotor was modeled. Dynamic balance tests were conducted to compare balance effects of planetary mechanism using two balance hole layouts. The dynamic balance test data showed that the unbalance reduction rate of separation column with modified balance hole structure is 9.9% higher than that of separation column with traditional balance hole structure, the unbalance reduction rate of planetary mechanism with modified balance hole structure is 18.2% higher than that of planetary mechanism with traditional balance hole structure; the balance accuracy of planetary mechanism with modified balance hole structure is significantly improved compared with that of planetary mechanism with traditional balance hole structure.
  • WANG Junguang, SUN Qinglin, LIANG Bing, YU Qingrong
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 253-259.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to study permeability evolution law of shale under cyclic loading and unloading of osmotic pressure, cyclic loading and unloading tests of shale with different confining pressures and different osmotic pressures were conducted by using the improved pulse attenuation gas permeability measurement device. The test results showed that initial confining pressure affects initial permeability of shale, and the larger the initial confining pressure, the smaller the initial permeability; in process of cyclic loading and unloading of osmotic pressure with constant confining pressure, the permeability increases with loading of osmotic pressure and decreases with unloading of osmotic pressure; in the same osmotic pressure loading and unloading cycle, permeability curve in loading stage doesn’t coincide with that in unloading stage, and the latter is above the former; the fitting result of the relation between permeability and cyclic loading and unloading of osmotic pressure is in accordance with quadratic function, and the correlation coefficient is more than 95%.
  • TIAN Xiaojie1, XIE Dashuai1, LIU Guijie1, XIE Yingchun1, DENG Wei2
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 260-267.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Here, the software ANSYS was used to perform fluid-structure interaction characteristics analysis of a gas-liquid two-phase flow marine riser including modal analysis and dynamic analysis. Modal analysis was used to study change of vibration modes of the riser with and without fluid-structure interaction and effects of fluid boundary conditions on natural frequencies and modal shapes of the riser. Then, natural frequencies solved using simulation analysis were compared with those solved using DNV formula to verify the correctness of simulation. Dynamic analysis was used to study fluid-structure interaction vibration analyses in single direction and double ones, and contrastively analyze both of them considering effects of riser support mode and fluid boundary conditions on riser vibration. Finally, the vibration reduction measures for riser were proposed. The study results provided an important theoretical basis for optimal design and operation reliability of marine risers.
  • HU Aijun, YAN Jiaxiang, BAI Zerui
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 268-273.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The structure of wind turbine gearbox is complex. When there are many faults in gear and bearing, fault diagnosis accuracy is low and some faults’ diagnosis is missed due to different fault intensities, mutual coupling between faults and noise interference. A multi-fault diagnosis method for wind turbine gearbox based on multi-point optimal minimum entropy deconvolution adjusted (MOMEDA) and enhanced cepstrum was proposed. Firstly, fault characteristic frequencies of different positions of gear and bearing were used to set reasonable deconvolution period, and the original signal was preprocessed by using MOMEDA. Then, enhanced cepstrum was used to further suppress noise interference and enhance fault features. Finally, prominent components in enhanced cepstrum were compared with fault characteristic frequencies of gearbox to determine the fault type. The analysis results of multi-fault vibration test data of actual wind turbine gearbox showed that the proposed method can effectively extract multi-fault feature information of gearbox.
  • ZHENG Zhi1,2, ZHANG Huaqin1, PAN Yue3
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 274-280.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The adaptive moment (Adam) estimation optimizer tends to make the long short-term memory (LSTM) neural network fall into local minimum value, which leads to excessive low accuracy of rolling bearing fault diagnosis. The searching area of the whale optimization algorithm (WOA) is too large, which leads to excessive low optimization efficiency. Here, aiming at the above two problems, WOA was improved, and LSTM was optimized to propose a new IWOA-LSTM method. It was shown that the proposed method endows WOA with momentum driven function and inherits the momentum term of Adam optimizer in LSTM to optimize the search area of cell weight value and improve the efficiency of weight value optimization; then, WOA is combined with Adam optimizer to update the weight value matrix to jump out of the local minimum value and improve the accuracy of fault diagnosis; in addition, effects of learning efficiency and iteration times on the diagnosis accuracy of IWOA-LSTM is systematically analyzed to realize highly effective fault diagnosis analysis. Three kinds of faults of inner ring, outer ring and rolling element of actual bearing data measured were analyzed, the results showed that the fault diagnosis efficiency of IWOA-LSTM is 47.60%, 38.06%, 37.62%, 26.82% and 22.71% higher than those of shallow BP neural network (BPNN), deep convolution neural network (CNN), deep gated recurrent unit neural network (GRU), LSTM and WOA-LSTM, respectively; the diagnosis accuracy is up to 97%.
  • SHAO Sujuan1, REN Chuanbo2, JING Dong2, YAN Tinghao2
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 281-290.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Here, a nonlinear active suspension system model with time delay feedback control was studied considering nonlinear characteristics of suspension spring and damping. The critical gain of delay independent stable region and the critical delay of stability switch were derived by using the generalized Sturm criterion. The effectiveness of the theoretical analysis was verified using numerical simulation with chosen parametric combinations in different stability intervals. Based on dynamic equations, nonlinear dynamic behavior of the suspension system under road excitation was studied by using bifurcation diagram, Poincare map and time domain diagram. The results showed that there is a small parameter interval in gain coefficient-damping coefficient  plane to realize delay independent stability, and the interval range increases with increase in suspension damping coefficient; when the controlled system has no delay independent stability, the system can have stability switching with change of time delay; these stability switches correspond to Hopf bifurcations when time delay crosses critical value; numerical simulation verifies the correctness of the theoretical analysis; when time delay is taken as a bifurcation parameter, the system’s path from quasi-periodic motion to chaotic one is observed, i.e., rupture of quasi-periodic torus.
  • LI Weipeng, CAO Yan, LI Lijuan
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(7): 291-296.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    k-medoids cluster algorithm(KCA) is an improved machine learning clustering algorithm. This method reveals the inherent properties and laws of the data,through selecting the initial clustering center ,updating the clustering center and learning the unmarked training samples, so as to distinguish the running state of the machine. In this paper, an orthogonal wavelet transform k-medoids clustering algorithm (OWTKCA) was proposed for diagnosis, which uses the orthogonal wavelet transform (OWT) method to extract the detailed signals as training samples, and uses the KCA method to classify them.The results of test data classification of rolling bearing show that this method can deal with complex mechanical vibration signals more effectively than KCA without extracting characteristic values, it obviously improves the clustering effect of fault data, shortens the clustering time and improves the efficiency of intelligent diagnosis.