28 April 2021, Volume 40 Issue 8
    

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  • LIU Lulu,LIU Xu,ZHAO Zhenhua,LUO Gang,CHEN Wei
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 1-9.
    Abstract ( 317 ) Download PDF ( 222 )   Knowledge map   Save
    In order to investigate the influences of padding pressure on the high velocity impact resistance of shear thickening fluid (STF) impregnated Kevlar fabrics, 50 kPa, 100 kPa, 200 kPa pressure were employed to compact the compound fabric. Ballistic impact tests were also carried out using titanium alloy simulated blades projectile. The experimental results show that the shear thickening phenomenon appear in the three STF systems, with the thickening period at 169-1 500 s-1 and thickening ratio at 56.4. The nano silica particles are uniformly attached to the surface of the fiber, bonding the fibers together. With the increase of padding pressure, the weight add-on decrease. The energy absorption of STF treated Kevlar fabrics is 29.4% higher than that of neat Kevlar, while the ballistic performance index (BPI) is inferior to untreated fabric. The energy absorption of STF-Kevlar fabrics decreases after padding, but still higher than neat fabric. The 100 kPa padding pressure achieves the maximum BPI. The trend of energy absorpted by fabric is consistent with the variation of deformation cone height.
  • YANG Mohan,CHEN Guo,YU Pingchao
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 10-18.
    Abstract ( 206 ) Download PDF ( 349 )   Knowledge map   Save
    Aiming to identify the connection parameters of a rotor system, a method for identifying the connection parameters was analyzed. The research object was a rotor tester with a diaphragm coupling. First, a finite element model of the rotor system was established, with bearing stiffness, supporting position, and diaphragm coupling stiffness as the identified parameters and then parameter sensitivity analysis was carried out. Second, based on a large number of simulation samples, a support vector regression (SVR) algorithm was used to construct a calculation surrogate model between connection parameters and natural frequencies. Third, by using a non-dominated sorting genetic algorithm Ⅱ (NSGA-Ⅱ), a multi-objective function based on the multi-order natural frequencies and modal test data was established to find Pareto optimal solution to the rotor connection parameters at the optimization intervals. Finally, multiple connection parameters of the rotor system were successfully identified. Compared with the test results, natural frequency simulation results of the modified dynamic model show that the accuracy of the first order reaches 97.62% and the second order reaches 99.70%.
  • ZENG Yunhui1,2,LUO Liping1,2,WANG Zhihong1,WANG Anning1,YU Yuanhong3
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 19-27.
    Abstract ( 171 ) Download PDF ( 339 )   Knowledge map   Save
    The objective of this paper is to investigates oscillatory and asymptotic behaviors of solutions of a class of third-order nonlinear neutral differential equations with continuously delay and damping terms. By using generalized Riccati transformations, integral averaging technique and some necessary technique, a set of new sufficient conditions was set for α≠β which ensure that every solution of the equations oscillates or converges to zero. The results improve and extend related criteria in recent literature.
  • WU Xingyu,WEI Yingsan,JIN Shuanbao,WANG Dong,ZHU Hao,HU Pengfei,SUN Fangxu
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 28-34.
    Abstract ( 207 ) Download PDF ( 185 )   Knowledge map   Save
    To predict the broadband radiated noise of rear-stator’s in subsonic axial fans, a calculation formula of cascade broadband acoustic power was introduced and derived. On this base, considering the actual fan stator working in the rotor wake, the rotor wake turbulence wave spectrum model was established with the Park-Gauss wake model and the broadband acoustic power calculation formula of the interaction between the stator and the rotor was derived. The difference between the prediction result by above formula and the Boeing and NASA rear-stator test result is within 5 dB, and the prediction result is more accurate than the rear-stator broadband sound power predicted by the Hanson’s formula. For the NASA test model, reducing the blade number can suppression fan broadband noise at high frequencies.
  • LIU Liyan1,WANG Yipeng1,ZHU Yong2,XIONG Guangming2,WANG Yuqi1,TAN Wei1
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 35-40.
    Abstract ( 239 ) Download PDF ( )   Knowledge map   Save
    In this paper, a solid model and a beam element model of an outmost U-tube of steam generator were established, and its vibration response was studied by Abaqus explicit dynamics. The vibration response of the U-tube supported by anti-vibration bars (AVBs) was studied by the solid model and the simplified form of anti-vibration bars in beam element model was studied by comparing the results of the solid model and the beam element model. The effect of gap on vibration response and fretting wear of the U-tube was studied by changing the gap between the U-tube and the anti-vibration bars. The analysis shows that: in the beam element model, the anti-vibration bars can be simplified into simple support. With the gap of the anti-vibration bars increase, the support effect of the U-tube becomes weaker, but the amplitude is not sensitive, while the wear power decreases obviously. The design of a steam generator should consider the support effectiveness and wear condition comprehensively and the support gap should be controlled within a reasonable range.
  • ZHAO Tianci,ZHAO Boming
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 41-49.
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    An algorithm for the identification of the strongest velocity pulse was proposed based on wavelet analysis, which considers three orthogonal components of the ground motion. The algorithm uses continuous wavelet transforms of three orthogonal components to identify the orientation of the velocity pulse that has the largest energy. The proposed algorithm analyzed 6 288 strong motion records of NGA-West 2 database and expanded the identification results. The statistical models of pulse amplitude, period with magnitude, and fault distance were established. The results show that the peak of the strongest velocity pulse gradually reduces with the increase of the fault distance, while gradually rises with the magnitude. Comparing with the fault normal or fault parallel orientation component, the strongest velocity pulse component has larger energy and smaller peak velocity. Compared with the Shahi, et al(2014) model, the predicted value of the proposed model is larger when the magnitude is small. With the strongest velocity pulses occupying more in the horizontal direction under a large magnitude, the difference between the two models gradually decreases.
  • LU Xiaohong,YANG Kun,LUAN Yihan,HOU Pengrong,GU Han
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 50-61.
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    Aiming at the chatter problems in thin-wall milling, the research progress of regenerative chatter theoretical models of thin-wall milling was discussed firstly in this work. Then, the milling force model, which is the root of the chatter, was discussed in depth, and the advantages and disadvantages of empirical models, finite element models, and analytical models of milling force were comparatively analyzed. Afterwards, the dynamic characteristics of thin-wall milling systems were discussed in detail. The methods of calculating the frequency response function of the tool tip were divided into experimental method, finite element method, and analytical method. The principles, research status, advantages, and disadvantages of these methods were discussed. Frequency-domain methods and time-domain methods for solving stability problems were comparatively analyzed. Related research on chatter stability of micro-milling meso-scale thin-wall was discussed. Finally, the research status and future directions of chatter stability of milling thin-walled parts were summarized and explored.
  • LI Yibing1,2,HUANG Dinghong1,MA Jianbo1,JIANG Li1,2
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 62-69.
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    It is difficult to extract the fault features of gears under complex operation conditions. The traditional fault diagnosis and recognition accuracy are easily affected by the manual feature extraction, and the information obtained by a single sensor is not comprehensive. To solve the above problems, a gear fault diagnosis method based on deep belief networks (DBN) and information fusion was proposed in this paper. Firstly, the vibration signals collected by each sensor were fused by multi-sensor information fusion technology at the data layer, and then DBN was used for adaptive feature extraction to achieve fault classification. In order to avoid the problem of model recognition accuracy degradation caused by artificial selection of DBN structural parameters, an improved shuffled frog leaping algorithm (ISFLA) was proposed to optimize DBN structural parameters. Experiments show that the information fusion and optimization methods proposed in this paper have higher fault recognition accuracy than BP neural network, DBN, and single sensor fault diagnosis.
  • WEI Qiang1,2,CUI Hongbin2,XIE Yaoguo2,QU Xianqiang2,LI Xu2
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 70-78.
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    In order to apply acoustic emission (AE) technology to the monitoring of fatigue cracks on oil and gas pipelines of offshore platforms, it is necessary to solve the problems of pipeline vibration interference and effective feature extraction of fatigue crack AE signals. The key to the problem lies in the study of feature extraction and identification algorithms of AE signals for fatigue cracks in pipeline structures. Based on existing research, a fatigue crack identification method was proposed based on empirical mode decomposition (EMD) as feature extraction. The problem of pipeline vibration interference and effective feature extraction of fatigue crack AE signals were linked. The characteristic elements were optimized to eliminate invalid noise interference information, and the fatigue crack signal was identified by a probabilistic neural network (PNN). The results show that PNN combined with the fatigue crack recognition method based on EMD as feature extraction can achieve a good result, which provides an experimental and theoretical basis for acoustic emission technology to monitor fatigue cracks of oil and gas pipelines on offshore platforms, and has certain guiding significance.
  • WANG Yunfeng1,WU Shuang2,LI Zhanxin3,XU Shuo3
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 79-84.
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    The quasi-zero-stiffness (QZS) isolator has character of high-static-low-dynamic-stiffness, and can be employed to suppress low-frequency vibration. Active damping control can reduce the resonance peak with keeping the transmissibility in high frequency band unchanged. It is effective to improve the performance of a QZS isolator by employing active damping control. In this paper, a buckled beam QZS isolator was adopted, and based on its dynamic model the active damping control was engaged to build an active-damping-QZS isolation system. The relationship between the isolation system transmissibility and active damping was studied by a theoretical method. Dynamic simulation was carried out in the SIMULINK software to study the performance of the isolation system in three conditions of sweep frequency disturbance, sinusoidal disturbance, and random disturbance. Simulation results indicate that in low-frequency-region (≤0.1 Hz) the amplitude of vibration was suppressed 8-32 dB, while in the high-frequency-region (≥10 Hz) the effect of vibration vilation was not less than 36 dB. In the random base disturbance condition, the vibration RMS was reduced 36 dB.
  • SUN Chaoming,SUN Kaihua,SUN Pengfei,GE Jiqiang
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 85-91.
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    For ultrasonic measurement of bolt axial force, the results are affected by complex correlated multiple factors, which leads to lower measurement accuracy. To measure the axial force of short bolts (M8×37) accurately, theoretical analysis was carried out and a model to estimate measurement error was developed. Several factors in the measurement (such as fluctuation of temperature, position difference of transducer, variation of couplant, etc.) were separated and controlled, and experiments were conducted in two stages to study the influence of multiple factors on the measurement results and to investigate the achievable measurement accuracy. The results show that when bolt axial force is measured by ultrasonic technique, coefficient transforming a time delay of ultrasound waves to the bolt axial force has a significant effect on measurement accuracy, so it should be calibrated precisely and it should be effectively matched with the measured bolt. The fluctuation of temperature and variations of coupling layer reduce the accuracy of measurement results. Hence, temperature compensation and an echo-echo analysis method should be adopted to eliminate the adverse effects from these factors. Inconsistency of transducer position will significantly reduce measurement accuracy; however, abnormal results can be identified and ruled out by correlation analysis. After reasonable and effective process control, measurement accuracy of bolt axial force can be improved, and thus requirements of engineering applications are met.
  • YUE Xiaofeng,XIE Chengneng,GAO Xueliang,ZHAO Hang,GUOSONG Wuming,HAO Zhaopeng
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 92-97.
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    An optimized finite element modeling method for flexible ring tires was proposed. This method optimizes the number of springs on the conventional flexible ring model supported by radial springs and uses the equivalent carcass deformation of B21 linear beam elements. In this paper, a universal testing machine was used to perform a uniaxial tensile test on a dumbbell-shaped tire rubber sheet, and the stress-strain curve was obtained. The finite element simulation software Abaqus was used to perform superelastic and viscoelastic evaluation and fitting on the material tensile data. A linear perturbation modal analysis was performed on the flexible ring model of a normal radial tire under load and load conditions, and the mode shapes and natural frequencies were extracted. Compared with Singlemodle analysis results, the validity and accuracy of this modeling method was verified. The model was also used to predict the law of the effects of speed, load, and tire pressure on the tire’s natural frequency under dynamic conditions, which provides a reference for tire structure analysis and design.
  • CHENG Jiayuan,REN Tingzhi,ZHANG Zilong,LIU Dawei,JIN Xin
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 98-109.
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    Aiming at the defect of an inertia cone crusher such as violent vibration and poor product indexes, a systematic analysis method combining theoretical analysis, multi-body dynamics, and a discrete element coupling method, and test verification was proposed. For model verification, the industrial tests were conducted on a GYP 1200 inertia cone crusher. Two different drive speeds were included in the experiments, and the testing devices were used to sample crusher performances such as displacement amplitude, power draw, product size distribution and throughput capacity in order to verify the validity of the coupling model and the analysis method. Furthermore, the behavior of the particle flow and the crushing force distribution in the concave were predicted. Finally, the influence of key parameters such as different drive speed and fixed cone mass on the dynamic performance of the crusher was discussed in detail. The coupling simulations and study results provided a basis for the improvement of linings wear, lowering manufacturing cost, and obtaining optimal operation parameters.
  • WANG Xiaoyu,TONG Jinyu,ZHENG Jinde,PAN Haiyang,PAN Ziwei
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 110-116.
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    Vibration signals of rolling bearings with labels are difficult to obtain under variable working conditions, which leads to low accuracy of fault diagnosis. Aiming at this problem, a new fault diagnosis method for rolling bearings was proposed based on complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) and manifold embedding distribution alignment. Firstly, CEEMDAN was used to decompose the vibration signals of rolling bearings under different working conditions, and some intrinsic mode components (IMF) were obtained. Secondly, the time-domain and frequency-domain features of IMF components with larger kurtosis were extracted to construct a multi-features sample set. The extracted features were embedded into the manifold space for manifold feature transformation and the transformed manifold features were aligned dynamically. Finally, the classification model was trained with source data and target data to obtain the fault diagnosis results of rolling bearings with unknown labels. The experimental results show that the proposed method can minimize the difference of feature distribution between domains, and improve the accuracy of rolling bearings state recognition effectively.
  • SHI Ruchao1,2,SUN Xiaowang3
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 117-123.
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    The ghost material method was extended to the interaction between stress wave and fluid-solid interface. An interfacial calculation algorithm based on modified ghost fluid method (MGFM) was proposed for stress wave refraction on fluid-solid interface. On this basis, we used the Zwas scheme and the WENO scheme, respectively, to discretize solid and fluid governing equations to numerically simulate stress wave penetrating water tanks. Numerical test shows that the ghost material method was convergent when applied for stress wave impacting at fluid-solid interface. The presented calculation algorithm has first order numerical accuracy. 1D numerical results coincide well with the exact solutions. This verifies the feasibility of the extension of the Ghost Material Method to stress wave reflection and transmission on fluid-solid interface. Numerical results of stress wave penetrating the water tank show that (i) the results by the ghost material method are closed to those by the arbitrary-Lagrangian-Eulerian (ALE) method, (ii) the intensity of the transmitted wave increases to some extent after increasing the pressure of water tank, (iii) stress wave refractions in the vicinity of fluid-solid interface are very closed under different pressures. The conclusions are practically significant to ship defense and design.
  • LI Baiyi1,WANG Guilin1,2,YUAN Jun3
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 124-130.
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    The deformation of foundation pit slope has the characteristics of non-stationarity and non-linearity. Currently, prediction models for foundation pit slope deformation usually use the data of a single monitoring point or overall monitoring points to predict, ignoring the correlation between different monitoring points. Three models, empirical mode decomposition-particle swarm optimization-back propagation neural network(EMD-PSO-BPNN) model, PSO-BPNN model, and BPNN model were built. Those models are based on single monitoring point data and related monitoring point data. Finally, a deep foundation pit slope in Chongqing was used to verify the correctness of those models. The following conclusions can be obtained. In the first place, The EMD model reduces the non-stationarity of the deformation data of the foundation pit slope, and makes the curve of each component smooth and stable, which improves the prediction accuracy. In the second place, the EMD-PSO-BPNN model has better ability of non-linear mapping, learning and self-adaptation. The prediction accuracy of the EMD-PSO-BPNN model is better than that of other models. In the last place, under the same model, the prediction accuracy of the prediction model based on correlation points is significantly higher than that of the prediction model based on single monitoring point.
  • HU Yan1,HUANG Panpan1,MA Ran1,CHEN Guangxiong2
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 131-136.
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    The integral dropper of a catenary system of Beijing—Tianjin high-speed railway was taken as the research object, and a coupling model of the pantograph-catenary system was established using a finite element method. The integral dropper was equivalent to a nonlinear spring which can only bear tension, and the coupling of the pantograph-catenary system was realized by a penalty function method. After verified the simulation model, the transient dynamic performance of integral dropper was studied. Results show that: while the relative speed between pantograph and catenary is 300 km/h or 350 km/h, the dominant frequency of dynamic force of different integral dropper in the same span is the same, and the dominant frequency is 7.8 Hz; While the relative speed is 300 km/h, the transverse vibration amplitude of different dropper′s upper and lower node is very small, which is less than 3 mm. Both the upper node and the lower node in a same dropper have the same vertical vibration phase, and the vibration dominant frequency of different dropper′s upper node or lower node is 1.42 Hz; while the relative speed range from 250-350 km/h, 3# dropper has a longest relaxation time compared with other droppers in a same spin.
  • ZHAI Yanchun1,2,LIANG Sen2,MA Jun1,REN Yuyan1,WANG Shaoqing2
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 137-142.
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    To further explore the vibration characteristics of viscoelastic composite damping plates, the complex vibration differential equation of viscoelastic composite damping plates was derived based on the mechanics of composite materials, the first order shear deformation theory, a piecewise displacement model and the Hamilton′s principle. The theoretical solution satisfying the displacement boundary condition was obtained by the Navier method, and the theoretical solution was verified by finite element simulation. Finally, based on the verified theoretical model, the change rule of vibration characteristics of viscoelastic composite damping plate with the structural parameters were explored theoretically.
  • LUO Peng1,2,HU Niaoqing1,2,SHEN Guoji1,2,CHENG Zhe1,2,ZHOU Zijun1,2
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 143-149.
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    The core of rolling bearing fault prognosis methods lies in the construction of a health indicator (HI). Most of the proposed HI is constructed artificially based on expert experience and it can only be applied to the trend analysis of a specific degradation stage of components. To solve the above problems, combined with the one-dimensional characteristics of vibration signals, a full life health indicator (FLHI) of rolling bearing intelligent extraction method based on one-dimensional deep convolutional neural network (1DDCNN) and principal component analysis (PCA) was proposed. 1DDCNN was used to extract features adaptively from the original signals, and it can deeply mine the degradation feature matrix that can represent the health state of the research object. And then, the extracted feature matrix was fused by the PCA method, so as to realize the FLHI intelligent extraction. The experimental results show that FLHI is more advantageous in terms of tendency, robustness, and monotonicity than the traditional HI.
  • GUO Xin1,ZHU Shiyao2,LIU Guanri3,YU Bing3,TANG Ke3,LEI Yongjun2
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 150-156.
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    A rigid clamp band system can provide a higher carrying capacity for a heavy-lift launch vehicle, but the research on its separation and capture dynamics process has not been deepened. In this paper, a nonlinear dynamic analysis model of a rigid clamp band system was established. The separation velocity, separation shock response, and capture motion of the rigid clamp band system were analyzed by an explicit dynamic simulation method. The influences of factors such as unlocking time and preload force on the parameters of separation and capture process were investigated. The results show that the extension of the unlocking time and the reduction of the preload force will result in the decrease in the separation speed and the impact acting on the satellite, the increase in the contact duration with the trapper, and the change in the separation movement of the clamp band, even causes the satellite to lean, which should be considered comprehensively in engineering applications.
  • ZHANG Letao,LIU Zhiqi,DONG Hongquan,LI Zhanlong,XU Yan
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 157-164.
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    To reduce the fatigue fracture caused by the friction and wear of a piston ring and ensure the volumetric efficiency and reliability of a motor, the friction of the piston ring was expressed linearly with the normal pressure and shear stress, the modal analysis method and the finite volume method were used to investigate the multi-body dynamics of the system and the fluid dynamics in the cylinder bore respectively, and the normal pressure and wall shear stress of the ring under different spindle angles, different width diameter ratios and arc cone angles were calculated. The results show that the change of displacement caused by the change of spindle angle has little effect on the friction, while the change of structural parameters of sealing ring has obvious effect. When the ratio of width to diameter is less than 0.3 and the angle of arc cone is less than 1.8°, the friction decreases with the ratio of width to diameter and cone angle. When the ratio of width to diameter is 0.3 and the angle of arc cone is 1.8°, the friction reaches the minimum and the maximum reduction rate is 28% and 25%, respectively; however, when the aspect ratio is greater than 0.3 and the arc cone angle is greater than 1.8°, the friction increases the aspect ratio and the cone angle. In addition, the shear stress increases with the ratio of width to diameter, but it is less affected by the cone angle of the arc surface. The research results provide theoretical basis and scientific basis for the design of piston motor piston ring friction reduction strategy.
  • LIN Henghui,ZHAO Yaobing
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 165-172.
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    As a classical flexible structure with quadratic and cubic nonlinearities, the suspended cables′ multi-type internal resonances are very easily excited. The paper aims at investigating influences of temperature on nonlinear dynamic behaviors of suspended cables considering simultaneous primary and two-to-one internal resonances. A kinematically condensed nonlinear model of a suspended cable considering temperature effects was introduced for the in-plane displacements by introducing a tension variation factor. Applying the Galerkin method and following the multiple scales procedure as to a weakly nonlinear system, both the polar and Cartesian forms of modulation equations were obtained when the higher/lower mode was excited directly. A complete dynamic scenario of vibration behaviors with thermal effects was presented quantitatively and qualitatively, e.g., force/frequency-response curves, periodic dynamic solutions, time displacement curves, phase plane diagrams, frequency spectrum, as well as Poincare sections. Numerical examples show that: the mode frequencies were affected by temperature changes significantly, and then the internal resonance would be changed induced by thermal effects. With an increase in temperature, the suspended cable with a smaller Irvine parameter would exhibit internal resonant responses. No matter the higher or the lower order was excited directly, the influence of temperature on the direct and internal excited response amplitudes were different. Temperature effects on the dynamic bifurcations (Hopf and periodic-doubling bifurcations) are much more apparent than the ones on the static bifurcations (saddle-node and pitck-fork bifurcations). The dynamic solutions as well as periodic motions are closely related to thermal effects, and significant different periodic motions were observed due to temperature changes. Besides, a good agreement between the perturbation solutions and the direct numerical integration ones could be observed.
  • HAN Jie,LU Guoyun
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 173-178.
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    The research boom of functional concrete is aroused by the concept of metamaterials. In the paper, based on an one-dimensional spring-mass system model, a three-dimensional vibration model of a unit cell that is taken as the study object was established under linearelastic deformation . The soft coating and mortar were assumed as spring that has equivalent stiffness and equivalent length in the model. Analyzed the force of the system, the equation of undamped free vibration was deduced using the D′Alembert law. Supposing the complex solution of the vibration, the natural frequency was acquired. Using the initial conditions, the vibration solution was obtained. The influences of the initial conditions, aggregate geometry data, the elastic modulus of the soft coating and the mortar on the natural frequency and the vibration characteristics were analyzed by using the MATLAB. The results show that: the natural frequency increases with the soft coating, mortar elastic modulus, and amplitude; when the soft coating elastic modulus and amplitude are the same, the natural frequency decreases with the soft coating thickness; the initial phase increases with the soft coating and mortar elastic modulus; the effect of different aggregate geometry data upon vibration characteristics is significant. The research of the metaconcrete structures resisted to high-frequency loads and impact loads has engineering guiding value.
  • HUANG Xuhong,YAN Weiming,XU Weibing,WANG Baoshun
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 179-186.
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    A pounding tuned rotary mass damper (PTRMD) was developed on the basis of the study of a tuned mass damper and a particle damper. The influence of various parameters on the vibration damping performance and mechanism is not clear. A PTRMD mechanical model was established by considering the collision and friction. The vibration process was divided into non-collision processes, collision processes, and viscous vibration process, and the corresponding motion equations were established separately. Finally, based on the numerical simulation, the parameter analysis was performed on the collision gap ratio, particle motion, frequency ratio, rolling friction coefficient, collision recovery coefficient, particle mass, the harmonic excitation intensity and frequency. The results show that when the particle motion frequency is small, the PTRMD damping effect increases linearly with the collision gap ratio, and the influence of the excitation amplitude is small. When the particle motion frequency is relatively large, the damping effect increases first and then decreases with the collision spacing ratio, and is greatly affected by the excitation amplitude.
  • DENG Feiyue1,2,QIANG Yawen2,HAO Rujiang2,MA Huaixiang2,GAO Fei2
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 187-193.
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    Aiming at the problem that weak fault feature is difficult to detect under strong background noise, an adaptive parametric dictionary design method was proposed. The proposed method is based on the idea of local segmentation and global analysis of the analyzed signal, and two indexes, correlation function (CF) and kurtosis, were used to evaluate the local matching degree and global matching degree between the Morlet wavelet and the fault signal. Moreover, the whale optimization algorithm (WOA) was introduced to the analysis process, and wavelet parameters could be identified automatically. Then the parametric dictionary was constructed by point-by-point time-shift, and the fault feature was detected by the sparse decomposition using the orthogonal matching pursuit (OMP). The proposed method was applied to analyze a simulated fault signal and gear fault signal, the results show that this method can extract weak fault feature effectively, and the diagnosis effect is better than the classical parametric dictionary based on a correlation filtering algorithm (CFA), wavelet denoising,and based on K-SVD learning dictionary.
     
  • ZHANG Ying1,2,AN Liqiang1,ZHOU Xingyin1,WANG Zhangqi1
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 194-200.
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    The bending-torsion coupling of laminate plates was analyzed from the modal analysis point view,symmetric off-axis orientations in different location were proposed to perform the coupling feature. The frequency and mode shapes were studied experimentally and numerically. The multi-point excitation and single point measurement method was used to acquire the vibration data of the laminates, and analyze the natural frequency and vibration mode parameters. The nodal lines of laminated cantilever plates in different coupling regions were studied, and compared with finite element simulation results. A new method was proposed to quantitatively describe the bending-torsional coupling performance of laminates using modal confidence factor moal assurance criterion(MAC). The results show that the coupling effect of the centrally coupled laminates is significant at low-order vibrations, while the coupling effect of the end-coupled laminates is significant at higher-order modes.
  • DU Xinxin1,2, GAN Bin3, JIAN Xiaochun2, FU Benyuan1, LIU Chunzhi2, LIAO Changrong1
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 201-208.
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    To improve the accuracy of mechanical models and achieve high precision prediction of dynamic characteristics of magnetorheological energy absorbers under impact, the Herschel-Bulkley constitutive model was modified by considering the apparent slip and wall slip conditions. By analyzing the influence of apparent slip and wall slip conditions on the pressure gradient in the damper channel, the results show that the pressure gradient decreases with the viscosity of carrier fluid decreasing under the influence of apparent slip condition, and the influence is more significant at low velocity. The pressure gradient increases with the viscosity of carrier fluid under the influence of apparent slip condition, while the effects on the overall structure are not important. The pressure gradient of the damper channel is obviously influenced by the wall slip condition, and the pressure gradient changes more significantly with the wall slip coefficient. Comparisons between measured and computed results under different currents and impact velocity reveal that the new model can well predict and characterize the mechanical properties of the magnetorheological energy absorber. The flow of magnetorheological fluid in the damper channel is mainly affected by the wall slip, and is slightly influenced by the apparent slip condition.
  • AN Miao1, LIU Qingkuan2,3, SUN Yifei1, ZHENG Yunfei4, JIA Yaya2, 3
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 209-215.
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    The wind load and wind-induced vibration of stay cables are prominent. It is of great significance to explore a new type of stay cable which can not only reduce drag force but also suppress vibration. It is reported that a wavy cylinder has the capability of reducing drag force and suppressing vibration at Reynolds number of 103-104. In fact, the Reynolds number of stay cables is actually 105. It is necessary to examine the aerodynamic performance of a wavy cylinder at high Reynolds number. Taking a wavy cylinder with specific geometric parameters as the research object, the aerodynamic characteristics during Reynolds number of 1.4 ×105-4.0×105 were studied through a wind tunnel test. The results show that the drag force coefficient of the wavy cylinder is larger than that of a uniform cross section cylinder. During the Reynolds number of 1.4×105-3.6×105, value is around 4%-8%. The value is up to 47% in 3.6×105-4.0×105. In critical Reynolds number region, the drag force coefficient of the wavy cylinder does not experience sharply declining which belongs to the transition from pre-critical regime (TrBL0) to one bubble regime (TrBL1). However, the drag force coefficient maintains stable with the increasing of Reynolds number. And the lift coefficient is always near 0 during whole tested Reynolds number. The variation of drag force coefficient, lift force coefficient, and wind pressure distribution with Reynolds number at different spanwise locations behave differently, which is mainly due to 3D geometric characteristics of the wavy cylinder.
  • CAO Yanmei, LI Dongwei, ZHANG Yuyu, YANG Lin
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 216-222.
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    The parameter distribution of the material damping ratio of shallow soil can be identified by inversion through the surface wave attenuation curve extracted by the multi-channel surface wave analysis method (MASW). However, the attenuation curves of surface waves are insensitive to the property changes of soil with larger depths and small spatial scales, and the damping ratio distribution of subsoil material is non-unique and uncertain. Therefore, in this paper, the variation of the damping ratio with depth is expressed by a non-Gaussian prior probability distribution model, and then is decomposed into the sum of standard Gaussian variables and also eigenvalues and eigenvectors by using the Nataf transformation and the Karhunen-Loeve decomposition. Moreover, on the basis of the Bayesian theory, the TLM-PML theory was combined with a half-power bandwidth method in the frequency-wavenumber domain to simulate the attenuation curves, which is compared with the experimental data to construct the likelihood function. The Monte Carlo Markov chain (MCMC)-Metropolis (MH) algorithm was used to obtain the posterior probability distribution model of soil damping ratio from the posterior sample data, and the convergence and independence of the Markov chain were validated so that multiple sets of independent posterior sample data were obtained. Finally, the independent posterior samples were used to calculate the vibration responses of the free field. The confidence interval with a certain degree of confidence was obtained using the kernel density estimation and thus was compared with the experimental data, which validates the rationality and reliability of the non-deterministic probability model of soil damping ratio proposed in this paper.
  • WEI Gang1, FENG Yan1, ZHANG Tiechun1, DENG Yunfei1, YANG Yonggang2
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 223-229.
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    The finite element analysis software Abaqus/explicit was used to simulate the impact of flat nosed projectile on TC4 titanium alloy plates with different thickness. The relationship was studied between impact failure characteristics and thickness change of double-layer targets. The effectiveness of the simulation model was verified by comparing the impact tests and simulation results. On this basis, the penetration resistance of a TC4 double-layer target was compared with the same thickness of a monolithic target. The results show that the ballistic limit of the double-layer structure is approximately linear with the total thickness of the target plate in the range of 2-16 mm for the flat nosed projectile with 12.68 mm diameter. Due to the special phenomenon that the ballistic limit has no obvious change with the increase of the thickness for the monolithic target plate in the range of 4-10 mm, the double-layer target has obvious advantages over the monolithic target in the thickness range. The ballistic limit is 43% higher than that of the monolithic target when the total thickness is 8 mm.
  • YING Shudi1, WANG Yan2, WU Jimei1, 3, WU Qiumin3
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 230-236.
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    The substrate material of Beiren PRC250 printing machine is web of the weight of 200-300 g/m2, the supporting roller in the multi-color printing process was used as the intermediate support. In this paper, a new P-type higher order differential quadrature method was proposed to solve the vibration of a moving web with intermediate supports. According to the Hamilton principle, the energy expression of the moving web was deduced, the shape function of the element was generated by the interpolation of the newly constructed C1 element. The influence of intermediate support and velocity on transverse vibration of the moving web was analyzed. The results show that complex frequency of the paper tape increases with the setting of the intermediate support, and the stable region becomes smaller with the increase of the speed under the constraint of the simple support and the opposite side free movement. The comparative was carried out by the CAE software, and it is proved that the new method to solve the vibration of the intermediate support moving paper tape is better than finite element software.
  • GAO Jun1, WU Zhibin1,2, KONG Lingyong1, LI Qi1
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 237-246.
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    Civil aircrafts have high requirements for the bird strike performance of a tail leading edge. The original auxiliary spar of a civil aircraft tail leading edge was an aluminum alloy machine part. Two novel configurations of the tail leading edge using aluminum alloy sheet metal auxiliary spars were proposed to optimize its bird strike resistance performance. The bird strike resistance of the three leading edges was calculated by the PAM-CRASH software, and the better one of the two new configurations was selected as the preferred configuration according to the analysis results. Bird strike tests were carried out for the original configuration and optimal configuration of the leading edge, and post-test simulations were carried out. The numerical calculation and test results show that the sheet metal auxiliary spar structure with corrugated stiffeners has no hard points, and the material has good ductility, which can absorb the energy during bird strike through large structure deformation and of many fasteners failure. The new structure greatly improves the bird strike resistance performance of the tail leading edge, and has obvious weight advantages, which can be applied to the civil aircraft tail leading edge design.
  • CHEN Changhong, TIAN Miao, SUN Meijing
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 247-254.
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    A two-dimensional composite piezoelectric phononic crystal was proposed, which is composed of a thin epoxy at the bottom and a nickel pillar at the top and deposited on the lithium niobate substrate. The dispersion relation of the structure was calculated by a finite element method, the bandgap characteristics of the composite piezoelectric phononic crystal were also carefully analyzed. The results show that the effective elastic modulus of the scatterer is reduced by introducing epoxy, so that the complete band gap of the surface acoustic waves (SAWs) is reduced and multiple SAW directional band gaps are opened. The transmission spectra were calculated to verify the existence of the band gap, and its transmission characteristics were discussed. The mechanism of band gap formation was analyzed by using the displacement fields of different eigenmodes at the edge X of Brillouin zone. Furthermore, the effect of the geometric parameters of the pillar on the SAW complete band gap and XM direction SAW band gap characteristics were also studied. It is found that, as the thickness of epoxy increases, multi-band gaps in the XM direction will merge to form a wide band gap of 158 MHz. The research content provides a reference for designing of electroacoustic equipment based on phononic crystal.
  • YUAN Xinyan, WANG Shuqing, ZHANG Yuan, FANG Hui, SONG Xiancang, XU Yihua
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 255-262.
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    In order to accurately study the numerical simulation of negative stiffness honeycombs with viscoelastic materials, a numerical simulation method that based on the viscoelastic generalized Maxwell model was proposed to simulate the compression properties of negative stiffness honeycombs. A dynamic mechanical analysis (DMA) testing was carried out for nylon 12, and the generalized Maxwell model was used to fit the measured data, thus, the dynamic modulus that reflected nylon 12 dynamic viscoelastic dimensionless modulus gi  and relaxation time τi were obtained. The finite element model of the negative stiffness honeycombs was established in Abaqus, and the dynamic viscoelastic parameters were applied to study the compression performance of the structure. At the same time, the compression experiment was carried out to verify the accuracy of the numerical simulation results. Finally, the influence of geometric parameters on compression the performance of structures was numerically simulated. The results show that the simulation analysis method based on the generalized viscoelastic Maxwell model can accurately simulate the compression performance of negative stiffness honeycombs, which provided help for the scientific prediction of the mechanical properties of negative stiffness honeycombs.
  • XIN Zhaowei1, HAN Zhijun2
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 263-268.
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    Based on an energy method and considering the stress wave effect, the buckling problem of a cylindrical shell subjected to a rigid mass was studied. The Lagrange function and the trial function satisfied the boundary condition were substituted into the second Lagrange equation. After the second-order linear partial differential equation was obtained, the analytical expression of the critical buckling speed of a rigid mass impacting cylindrical shell was obtained by analyzing the properties of the equations. The influence of critical length, impact mass, axial mode number, circumferential mode number and diameter-thickness ratio on buckling was discussed by analyzing the examples. The results show that the stress wave effect, initial kinetic energy, and diameter-thickness ratio have a significant effect on the dynamic buckling of cylindrical shells; the higher-order modes of buckling and the buckling of cylindrical shell were easily motivated by high-speed impact.
  • ZHANG Chunhui1, ZHANG Fei1,2, ZHANG Lei1, WANG Zhijun2
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 269-277.
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    To study the mechanical properties of marine welded steel sheets under dynamic load, this study carried out quasi-static tensile tests, high temperature tensile tests and SHPB dynamic compression tests of typical marine welded steel base metals, welds and heat affected zones. The mechanical behavior of welded steel materials under different stress states was analyzed. Based on the mechanical properties test results, a constitutive models of welded steel base metal, weld and heat affected zone materials were fitted. The results show that under quasi-static conditions, the yield strength and tensile strength of the weld and heat affected zone materials are larger than that of the base metal and the elongation is smaller than that of the base metal. At high strain rate, the ability of the material in the heat-affected zone to resist plastic deformation is significantly stronger than the other two materials, and the ability to resist plastic deformation increases with strain rate. The welded plate base metal, weld and heat affected zone materials all exhibit strain rate effects and temperature effects. The heat affected zone is the area where the impact properties of the welded plate are relatively weak. The established Johnson-Cook model can describe the mechanical properties of welded steel plates under blast load.
  • ZENG Qin’e, GAO Liang, HOU Bowen, MA Chaozhi
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 278-285.
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    In this paper, noise field tests were carried out in an underground station platform. And a suitable finite element model was established to analyze structure-borne noise induced by the load of a rail transit train through the refined simulation of the station structure. The sound field distribution characteristics of low-frequency structure-borne noise in the station platform space were analyzed. At the same time, acoustic mode was used to reveal the propagation mechanism of low-frequency noise in the station platform. The analysis results indicate that: the low frequency noise in the underground station platform appears an obvious peak at 50 Hz-85 Hz, which is radiated mainly from the vibration of the platform board. The sound pressure level at different locations shows a significant volatility with a fluctuation of 12 dB, and the sound pressure level varies within 68.6 dB-80.4 dB. The sensitive resonant frequency of the platform acoustic cavity has a significant impact on low-frequency structural noise, which will amplify the low-frequency structural noise of the station. Changing the height of station platform is a useful method to improve the station sound environment.
  • LIU Zhouqiang, XU Yan
    JOURNAL OF VIBRATION AND SHOCK. 2021, 40(8): 286-294.
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    As a key node of urban traffic network, the seismic safety of overpass is very important. In view of the vulnerability of overpasses under the action of near-fault ground motion and the fact that such ground motion records are few, a two-step method was proposed to construct near-fault ground motion input based on the comparison of simplified impulse simulation and real ground motion records. And the seismic response characteristics of overpasses under such action were studied. It was found that when the ratio of the simplified pulse period to the basic period of each substructure of the overpass is between 1 and 3, the structural reaction is intense, and when it is around 1.5, the internal force of the pier bottom reaches the maximum value. When the real near-fault ground motion records corresponding to the most disadvantageous simplified pulse period of each substructure are used to input the structure, the error of the seismic response of the ramp bridge in a short period is about 15% under the simulated input of a single simplified velocity pulse and real one. For ramp bridges and main bridges with medium and long period, it is necessary to adopt the two-step construction method to superimpose the high frequency components, so as to better restore the effect of the real ground motion record.