15 April 2018, Volume 37 Issue 9
    

  • Select all
    |
  • WANG Zhihao, GAO Hui, ZHANG Xinzhong, TIAN Wenwen
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 1-7.
    Abstract ( 528 ) Download PDF ( 365 )   Knowledge map   Save
    To realize optimal design for structure and magnetic circuit of a pendulum tuned mass damper (PTMD) with eddy current damping, the overall structure of PTMD with a planar eddy-current damper (PECD) was studied qualitatively. The effects of magnetic field attractive force between PTMD and PECD on vibration frequency of PTMD, and those of magnetic circuit layout on equivalent damping coefficient of PECD were investigated using theoretical analysis, model tests and 3D electromagnetic field finite element simulation. The results showed that PECD should be installed at the bottom of the moving mass of PTMD, the magnetic field attractive force makes the vibration frequency of PTMD increase; the pendulum initial length of PTMD should be appropriately adjusted to avoid TMD detuning; the energy-dissipating effect of PECD is improved by reducing magnetic field gap, increasing steel plate thickness properly and optimizing copper plate thickness; along the moving direction of PTMD, adjacent permanent magnets’ magnetic poles need to be arranged in a staggered manner, their optimal interval is determined with FEM; while along the direction perpendicular to the moving direction of PTMD, adjacent permanent magnets’ magnetic poles need to be arranged in the same polarity manner, they are close enough.

  • GAO Qidong1,2,LU Wenbo1,2,LENG Zhendong1,2YANG Zhaowei1,2,YAN Peng1,2,CHEN Ming1,2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 8-16.
    Abstract ( 317 ) Download PDF ( 628 )   Knowledge map   Save
    The influence action mechanism of detonating position was analysed in a perspective of propagation and reflection of blast stress wave. Based on drill-blast excavation of a tunnel, the slotting effect of a cut-hole and the corresponding induced blast vibration responses of the support structure under different detonating locations were analyzed contrastively with numerical simulation. Results indicated that both the cut-hole’s slotting effect and blast vibration responses of the support structure have larger differences under different detonating locations; the blast vibration of the support structure under direct initiation is minimum in favor of the support structure’s safety, but the cut hole’s slotting effect is poor; the slotting effect of reverse initiation is best, but the induced blast vibration of the support structure is maximum to seriously threaten the support structure’s safety; under middle initiation, both the slotting effect and the blast vibration of the support structure are mediate. According to different conditions of surrounding rock, the selection of cut holes’ detonating location was optimized
  • LI Zhiguo1, WANG Qi1,2, LIAO Haili1, WEI Yifeng3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 17-24.
    Abstract ( 298 ) Download PDF ( )   Knowledge map   Save
    Influences of inclined web slope on flutter performance of flat box girders and their quantification were studied. Two sets of sectional models with fixed width and height, and different slopes of inclined web were designed and fabricated, dynamic parameters of the detecting system were kept unchanging, and flutter performances of different models were obtained with wind tunnel tests. The results showed that when the ratio of width to height for flat box girders is 11, effects of inclined web slope on the flutter critical wind speed are significant under the condition of 5 wind attack angle, but they are not obvious under the condition of 0 wind attack angle; when the ratio of width to height is 7, effects of inclined web slope on flutter are not obvious under either 5 wind attack angle or 0 one; changes of inclined web slope make flutter coupled derivative H3* and flutter direct derivative A2* vary significantly to cause greater variation of flutter critical wind speed. Finally, according test data and calculating results, adopting the flutter factor in the analytical calculation formula for the flutter critical wind speed, effects of wind attack angle inclined web slope on flat box girders’ flutter were quantified. Flutter factors under different conditions were deduced. It was shown that compared with the single reduced factor in the current flutter calculation code, conditioned flutter factors can be used to accurately calculate the flutter critical wind speed for flat box girders. The results provided a reference for effectively improving the aerodynamic layout of flat box girders.
  • FANG Genshen YANG Yongxin GE Yaojun ZHOU Zhiyong
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 25-31.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Flutter performance of PK section girders for long-span bridges in the finished bridge state was investigated based on a cable-stayed bridge with the main span of 820 meters by means of sectional models’ wind tunnel tests and the 2D-3DOF method. A comprehensive criterion with root mean square (RMS) deviation, peak factor and damping ratio of torsional responses of girders under critical wind speed to determine the critical point of “soft flutter”was proposed. The flutter control effect and flutter drive mechanism for 3 sizes of airflow-suppressing lamina were explored. The study showed that PK section girders in the finished bridge state have obvious “soft flutter” characteristics, the effects of wind attack angle are also obvious, especially, the flutter critical wind speeds under the wind attack angle of 0° and 3° have a remarkable difference, girders reveal bending-torsion coupled flutter under the wind attack angle of 0, while they reveal single–DOF torsion flutter under the wind attack angle of 3 due to their obviously different aerodynamic damping variation laws; airflow-suppressing lamina can effectively improve the flutter critical wind speed of PK section girders under the wind attack angle of 3° to increase flutter coupling level; although more aerodynamic damping going against coupling are excited with airflow-suppressing laminas installed, the aerodynamic damping generated by torsional motion can enhance the system’s stability; the competition among different types of aerodynamic damping determines if the system diverges.
  • SUN Dong1, WANG Xin-jie1,WANG Jiong1,CHEN Chao2,TANG Yu-juan3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 32-36.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    It is significant to study failure modes of ultrasonic motors applied in weapon systems under shock environment. The possible failure modes of key components in ultrasonic motors include fracture and delamination of piezoelectric ceramics, drift of working frequency due to plastic deformation of the stator, and reduction or disappearance of pre-pressure due to stator and rotor’ plastic deformation and bolt-loosening in pre-tightening force mechanisms. The stress states and stress wave transmission process of each component of the motors were analyzed with dynamic simulation. It was shown that the pre-tightening force mechanism is the part to be damaged most easily in the whole structure of a motor. An air gun was used to conduct the impact-overload tests for an ultrasonic motor. When the impact load reached 26546g, bolts loosened, the pre-tightening force mechanism became invalid, but other parts had no obvious damages or deformations. The results provided a theoretical basis and improvement measures for the application of ultrasonic motors in weapon systems under shock environment.



  • GAO Yun1, 2, YANG Jia-dong1, ZOU Li3, ZONG Zhi3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 37-43.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Effects of surface roughness on vortex-induced vibration (VIV) characteristics of a circular cylinder were studied numerically. The cylinder’s VIV response amplitude, vortex-shedding frequency, structural vibration frequency and lock-in region under different surface roughnesses were analyzed contrastively. The numerical results showed that the whole reduced velocity interval can be divided into four regions including region I, region II, region III and region IV based on the cylinder’s VIV response amplitude and frequency; with increase in roughness, the maximum value of the cylinder’s VIV drops, the beginning point of the lock-in region slowly shifts to an earlier position while the lock-in region’s ending point quickly shifts an earlier one, the width of the lock-in region becomes gradually narrower.



  • ZHANG Ai-ping1, LI Ya-xuan1, XIAO Bin1, SHI Shuang-xia1, CAO Li-hua1,GAO Chao1,QIU Rui2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 44-49.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    It is sure that the responses of practical structural dynamic systems considering parametric uncertainty under deterministic excitations also have characteristics of randomness. The acquisition of their statistical features is a difficult problem in vibration analysis of stochastic structural dynamic systems. Here, under the condition of a system’s uncertain characteristic parameters obeying Gauss distribution, based on Fourier-Hermite polynomial expansion, the stochastic responses of the dynamic system were solved using the generalized model dimension-reducing and the multi-dimensional Gauss-Hermite numerical quadrature to determine expansion coefficients, and obtain the system’s responses approximate solution in the form of explicit orthogonal polynomial function expansion. Then, the solution was embedded with the local Monte Carlo simulation (MCS) to form the statistical analysis method for random vibration systems, and acquire the statistical characteristics of the system responses. Furthermore, using FEM modeling, based on the proposed above method, the statistical analysis was conducted for plate structures’ vibration responses. Numerical simulation results showed that the statistical analysis results using the proposed method agree well with those using the direct MCS method to obtain statistical characteristics of random plate structures’ vibration responses; the statistical characteristics of random plate structures’ vibration responses under a continuous stiffness boundary condition can be predicted based on the FEM mesh refinement of a discrete stiffness boundary.
  • WANG Kai1LI Yu1 LIU Hou-lin1 XIA Chen1 LIU Zhong-cun2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 50-55.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Hydrodynamic noise excited by a dipole acoustic source in a five-stage diffuser centrifugal pump was studied with Lighthill acoustic analogy theory. The transient flow field inside the five-stage centrifugal pump was numerically simulated, and the dipole acoustic source on wall surface of all stages was extracted. The direct boundary element method was used to calculate the internal flow-induced noise in the pump. The pump’s vibration was calculated with the modal response method,vibration tests for the pump were also conducted. It was verified that the numerical prediction method for flow-induced noise in the pump has some certain feasibility. The results showed that with increase in flow rate, noise in the pump firstly increases, then decreases and increases again, the noise level is the minimum under the designed working condition; in the sound pressure frequency distribution, BPF2 and noise energy on its characteristic frequency increase with increase in flow rate, noise energy on a higher frequency range increases significantly; blade numbers of the first-stage impeller, another four stages’ impellers and positive guide vane have larger effects on flow induced noise, while blade number of the negative guide vane has a relatively smaller effect. The study results provided a reference for the design of low-noise multi-stage centrifugal pumps.
  • PENG Qi’an, WANG Sanmin, ZHI Changjian, LI Bo
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 56-60.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    With increase in array elements, the computation amount to analyze an array deployable structure is huge based on the conventional FEM dynamic analysis method, even the computation becomes impossible. The specification dynamic method (SDM) for a planar linear array deployable structure with scissor-like elements was proposed according to its feature of it being regularly composed of element mechanisms. The superposition node DOFs among element mechanisms and internal node DOFs were separated with this method to realize element characteristic matrices added end to end circularly, and obtain the global stiffness matrix and mass one of an array deployable structure. Taking a 55 planar linear array deployable structure with scissor-like elements as an example, its natural frequencies and dynamic responses were analyzed with the SDM. The results showed that the structure’s natural frequency decreases to 0 Hz rapidly when its deployable angle is close to 0 or 180; when external loads are applied, the dynamic responses of the system are periodic vibration, periodic vibration with the maximum amplitude attenuated, and no vibration, respectively under undamped, underdamped and overdamped conditions; the structure with the deployable angle close to 0 or 180 is unstable, the safe range of the deployable angle should be 20 to 160; in addition, appropriately increasing damping can reduce the structure’s vibration effectively; the SDM can be used to improve modeling efficiency, and it is easy to be regularly programmed for computation. 
  • DONG Cheng1, 2,LIU Wen-jie1, 2,LI Liang 2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 61-67.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The factors affecting dynamic resilient modulus of subgrade compacted silty clay were investigated with dynamic tri-axis tests to analyze the dependency of dynamic resilient modulus on deviator stress and body stress. Through the two-factor regression analysis, an improved prediction model with four parameters was proposed by introducing k4 on the basis of AASHTO-N37A dynamic resilient modulus prediction model. In order to apply the improved model in finite element calculation, the accurate consistent tangent stiffness matrix of this model was derived based on the general Hooke law. The improved model was transplanted into the FE software ABAQUS by compiling the user material subroutine (UMAT), the computation validation was made under conditions of a single soil element and a subgrade-pavement structure. The results showed that the four-parameter improved model can better predict the dynamic resilient modulus of silty clay under different compaction levels; the soil body element’s stress-strain relation calculated with the improved model developed secondarily agreed well with the analytical solution; the improved model being applied in the analysis of subgrade-pavement structure can reflect differences of the dynamic resilient modulus at different locations of subgrade due to different stresses, and also reflect evolution of the dynamic resilient modulus under vehicle loading to realize the dynamic coupling between stress states and dynamic resilient modulus. The study provided a more actual numerical simulation method for design of subgrade-pavement structures.

  • HU Guang-shen1, LU Ze-qi1,CHEN Li-qun1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 68-73.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aiming at vibration systems with nonlinear stiffness and nonlinear damping, two parametric identification methods were proposed. The first method was based on vibration amplitude jumping phenomenon in a nonlinear vibration system, the system was excited with a swept-sine excitation, frequency and amplitude of the amplitude-jumping point’s displacement were obtained through measurement, then the harmonic balance method was used to recognize the nonlinear vibration system’s stiffness and damping. The second method was involved in the time domain transient response of a nonlinear system, Hilbert transformation was used to gain the free vibration response’s amplitude and phase angle of the system, then combining with the analytical solution to the system excited with a transient excitation, the system’s nonlinear stiffness and nonlinear damping were recognized. Taking a vibration isolation system with nonlinear stiffness and nonlinear damping as an example, the two methods mentioned above were verified through numerical simulation. It was shown that the parametric recognition results using these two methods agree well each other. The study results provided a theoretical guide for parametric identification of vibration isolation systems with nonlinear stiffness and nonlinear damping.
  • LU Ming-fei, YE Ji-hong
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 74-79.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Stability is a key factor in design and analysis of single-layer cylindrical domes. From the perspective of joint well-formedness, the relative gradient of joint well-formedness (gra_r) was defined here to fully reflect the static stability of structures and consider the core part directly related to stability of external factors, its minimum value (gra_rmin) was directly related to stability loads. It was shown that gra_r can quantitatively measure a structure’s tendency to lose stability and reveal domes’ unstable mechanism. On this basis, the stability optimization design method for single-layer cylindrical domes was proposed. Using the stability optimization model, the maximization of gra_rmin was taken as an objective, and discrete rods’ cross-sections as variables, various design constraint conditions specified in the code were considered, the force-bearing ability for the structure stability was improved under the premise of a given steel-consuming amount. Two practical engineering examples verified the effectiveness of the proposed stability optimization design method for single-layer cylindrical domes.
  • YAO Hongliang1, WANG Tongzhao1, CAO Yanbo1, WEN Bangchun1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 80-85.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To realize vibration suppression of a rotor system with variable rotating speed, a new type of dynamic absorber with tunable stiffness was proposed. The stiffness and natural frequency of the absorber could be adjusted with a variable stiffness mechanism composed of permanent magnets. Firstly, the structure of the absorber was designed, the dynamic equation of the rotor-absorber with a permanent magnet variable stiffness was established, and the working principle of the absorber was analyzed. Secondly, the rotor-permanent magnet tunable stiffness absorber test platform and its control system were built, a PID control program was compiled. Finally, the effectiveness test of the permanent magnet tunable stiffness mechanism, the validity test for frequency-sweeping and vibration reduction effect and the rotor constant speed control test were conducted on the test platform. The results showed that the tunable stiffness dynamic absorber designed can acquire vibration suppression effect.



  • HAN Xiaolei1,2 YOU Tao1 JI Jing1,2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 86-91.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Deficiencies existing in China code of buildings aseismic design for long-period range of an acceleration response spectrum were analyzed. According to the definition of site classification and the seismic ground motion feature period Tg in the seismic ground motion parameters zonation map of China, 7274 ground motion records selected from 1146 real strong earthquake events with the rank  5.0 were divided into groups. Based on the random vibration theory, the statistical energy density distribution and acceleration response spectrum were obtained with the conversion relation among seismic ground motion’s Fourier amplitude spectrum, power spectrum and designed response spectrum. The attenuation laws of energy density distribution and acceleration response spectrum were studied. Through regression analysis, the reasonable descending form and slope value in long-period range of the designed response spectrum were deduced under different site conditions. The results provided a reference for the code modification.


  • PENG Xia 1,2,3,GONG Xian-sheng1,2,WU Xian-zhao1,2,ZOU Sheng-yong4
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 92-99.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The forms of grooves on a drum for ultra-deep mine hoist have extremely important effects on vibration of hoisting wire rope and smooth winding. Here, the effects of transition zone between parallel broken line grooves of a multi-layer winding drum on vibration of hoisting wire rope under different asymmetric parameters were studied. The suspension rope’s lateral vibration of of hoisting wire rope was studied and its amplitude was taken as the evaluation index for asymmetric forms of multi-layer winding grooves. On the basis of studying the movement behavior in the transition zone of a mine hoisting system and wire rope, the dynamic partial differential equations of the hoisting system and the excitation function were established, and they were discretized into ordinary differential equations with Galerkin method. Taking a certain ultra-deep mine as an example, the effects of transition zone between parallel broken line grooves on vibration of the hoisting system under different asymmetric parameters were studied with numerical simulation. The results showed that either symmetric groove form or asymmetric one depends on the hoisting system’s parameters. The study method and the study results provided a scientific guidance for correctly designing and selecting parallel broken line grooves on a multi-layer winding drum.



  • YANG Yang1,2, WANG Ya-ping2, XU Cheng2, Chen liqing1, ZHANG Wei2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 100-105.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Here, the gun-controlling characteristics of a shooter were studied during continuous firing. Shooters’ 15 continuous firing kinematic attitude data were captured with a 3-D motion capturing system. The human-rifle musculoskeletal model was built adopting the human body bio-mechanics modeling software AnyBody. Using the shooting kinematic data to drive the human-rifle model, the laws for muscle and joint reaction forces of a shooter were obtained based on the principles of inverse dynamics. The simulation results showed that the proposed model can better simulate the bio-mechanical characteristics of human body under recoil loads during continuous firing; the study results provide a basis for deeply studying dynamic responses of human body under continuous impacts in shooting process.


  • WANG Hao,KE Shitang
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 106-113.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Excessive large local wind pressure is one of important factors causing a cooling tower’s local damage and destruction, and the interference effect of tower groups can significantly change cooling tower’s local wind pressure distribution pattern. Taking the world’s highest cooling tower (220m) now being built as the engineering background, the wind tunnel tests for a single tower, two towers and five typical four-tower combinations were conducted. The distribution features of four-tower combinations’ wind pressure interference factor were discussed. Influence laws of four-tower combinations on distribution modes of cooling towers’ mean wind pressure and fluctuating one were analyzed. Wind pressure signals were decomposed and analyzed in time-frequency domain based on the mathematical statistics and Hilbert-Huang transformation (HHT). The results showed that the interference effect of four-tower combinations on the middle tower is the maximum; the influence of four-tower combination effect on mean wind pressure mainly focuses on the minimum negative pressure area and leeward zone; in 5 typical four-tower combinations, the diamond scheme has the smallest static interference on local wind pressure, and the oblique L-shaped scheme has the smallest dynamic interference on local wind pressure.

  • ZHANG Yi-min, ZHANG Rui, ZHU Li-sha, ZHAO Chun-yu
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 114-119.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The dynamic characteristics of MG500/1180-WD shearer’s rocker arm were studied aiming at the problem of its poor reliability under cutting loads. The simplified finite element (FE) model for the arm was established and its natural frequencies and main modal shapes were obtained with modal analysis. Modal analysis showed that the main vibration modes of the arm are bending-torsional vibration of planet head and motor shell. Through test modal analysis, taking its natural frequencies as the judgement index, the FE model was validated. Choosing 5 design variables including motor shell’s wall thickness, etc., the variation law of the arm’s natural frequencies with the design variables was studied. Harmonic response analysis for the arm was conducted under the condition of heavy cutting loads, and the vibration responses of the arm were calculated. The results showed that the thickness of old pond side wall in the middle of the arm is the key factor influencing the arm’s natural characteristics; the arm’s dynamic stresses are larger under loads with double of the planet’s 1st frequency, double of the spur gear’s 1st one, double of the spur gear’s 2nd one, and the 8th natural frequency; the arm’s elastic vibration mainly has features of its 1st and 3rd modal shapes to cause stress concentration at the arm hinge ear; the analysis results provide a reference for the optimal design and reliability analysis of a shearer’s rocker arm.
  • LIN Wei-guo WU Shi-en
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 120-126.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A non-intrusive acoustic monitoring method for valve internal leakage was proposed using a dual-sensor structure. The sensing device was designed to be able to adjust contact level between sensor and pipe wall and lock them, and it could be loaded and unloaded quickly. The time-frequency domain features of interference acoustic signals sampled under the conditions of valve normal state, valve internal leakage, pipe tapping, pump starting during valve being in open or close state were analyzed contrastively. The feature extraction approach based on the wavelet packet energy ratio for valve internal leakage acoustic signals was proposed. It was shown that this method can effectively distinguish valve internal leakage and external interferences; it has a higher leakage detection sensitivity, it can greatly reduce the sampling frequency and the difficulty degree of valve internal leakage diagnosis. 

        
  • LIU Wei 1 JIANG Yi 1 DONG Xiao-tong 1 WEI Heng 2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 127-132.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Multi-axle trucks are prone to rollover in their driving due to its giant size, larger mass and higher gravity center. Here, the rollover model of multi-axle trucks was studied. A 3-DOF nonlinear rollover model for them was built considering characteristics of multi-axis steering, tire nonlinearity and suspension nonlinearity. Real vehicle tests were conducted to verify the correctness of the model. Effects of the main nonlinear parameters in the model on the vehicle’s dynamic responses were studied based on the nonlinear model. The results showed that the lateral leaning stiffness of tire has little effect on the vehicle attitudes within a certain range; the rigidity of hydro-pneumatic spring of suspension has a significant influence on the vehicle roll angle, while it has little effect on the lateral acceleration of the vehicle.
     
  • LI Yanwei1,2,3, WANG Chaohui2, SHI Xin3, CHEN Sen2, FENG,Dongjie2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 133-141.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To eliminate technical defects of piezoelectric transducers used in road engineering, piezoelectric stack harvesting unit structures being applicable to road power generation were preferably selected and their sizes were optimized, 8 piezoelectric stack harvesting units used in road engineering were prepared. Their structural strengths were evaluated by means of mechanical property tests. The test fixtures for piezoelectric harvesting units were developed, and the anlog test systems for electricity generating performance were constructed. The electricity generating performance of piezoelectric harvesting units was studied, the electrical energy output effect of power pavement’s small-size specimens were measured. The results showed that the structural strength of the piezoelectric stack harvesting units prepared is good to meet the requirements of power pavement’s construction and working; within the test range, magnitude of load, loading frequency, thickness of piezoelectric ceramic piece and layer number of stack are positively correlated to electricity generating performance of piezoelectric harvesting units; the maximum open circuit voltage and the maximum power of piezoelectric stack harvesting units with monolithic thickness of 1.0mm can reach 37.8V and 183.2 mW, respectively; the energy output of the typical power pavement’s small specimen is 11.06mW, so it has an ideal application prospect.
  • QIN Dong-bin DU Jing-li
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 142-148.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Electrostatic formed membrane reflector antenna is a new type of antennas. Its reflective surface accuracy is its important performance index. It is necessary to study shape errors existing in forming of membrane reflector. Firstly, shape errors were classified into principle errors and manufacturing errors, manufacturing errors were divided into mosaic errors, paste errors and boundary errors. Then, reflector forming simulation was realized based on the finite element method to obtain principle errors. Mosaic errors were presented numerically through rotation and radical translation of film surface design position. Paste bars were approximately equivalent to cable elements, different cable stresses were set to simulate paste errors. Boundary errors were presented with skirt boundary cable force errors. Based on the above mentioned errors, the reflector’s cutting layout optimization model was proposed. Ring number, cutting number per ring and voltage were taken as variables to be optimized, the shape precision of membrane reflector was taken as the objective to be optimized, and the positivity and uniformity of membrane stress were taken as constraints. A technique combining the gradient method and the genetic algorithm was proposed to solve this optimization model including continuous and discrete variables with high non-linearity. The validity of the optimization model was verified with a numerical example of a 0.55m membrane reflector antenna model.
  • Liu Kun, Fu Jie, Wang Zhe, Wang Zili
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 149-154.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Web girders of ship hull structures are often damaged due to in-plane impact load during ships collision and grounding accidents. Here, the specimens were scaled down and simplified from a typical web girder structure in ships. A set of unstiffened web girders and a set of longitudinally stiffened ones were designed. The quasi-static impact tests and finite element simulations for the two sets of web girders subjected to in-plane impact loads were conducted. Their deformation mechanisms were analyzed from two sides of impact loads and damage deformation. The results showed that the longitudinally stiffened web girders can improve greatly their structural resistance forces; two types of web girders have different wrinkle deformation modes in middle section of ribbed plates; the results can provide a basis for the determination of web girders’ deformation modes in subsequent analytical methods.



  • GUAN Qing-hai1,ZHOU Yan1, LI Jia-wu2,HU Zhao-tong2,LIU Jian-xin 2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 155-160.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to study effects of parameters on nonlinear aerostatic stability of a long-span pedestrian suspension bridge, using the double-iteration numerical algorithm, effects of parameters including structural additional wind attack angle, initial wind attack angle of incoming flow, wind loads of non-main girder structures, wind resistance cable and central buckle structure measures on nonlinear aerostatic stability for a pedestrian suspension bridge with main span of 420m were analyzed. The analysis results showed that regardless of additional wind attack angle enlarging the critical wind speed of aerostatic instability, different development paths of aerostatic loads under different positive and negative initial attack angles make the positive attack angle worsen the aerostatic stability and the negative attack angle  improve the aerostatic stability; wind loads of non-main girder structure have little effect on the critical wind speed of aerostatic instability, while wind load of wind resistance cable has great effects on displacements under static wind of main girder, wind load of main tower has the least effect on displacements under static wind of main girder; wind resistance cable can change aerostatic instability status of a long-span pedestrian suspension bridge and greatly improve its aerostatic stability; for a pedestrian suspension bridge with main span of 420m, it is difficult to only depend on central buckle structure measures for the design scheme without wind resistance cable to get sufficient aerostatic stability.
  • LIU Ning 1,2,LIU Sixin 1,XI Jiaxin 2,ZHANG Xuebing 3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 161-167.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    With the signal acquisition and processing technology, the sensor technology, and the wireless communication technology’s continuing to make progress, a lot of studies are made to use vibration response signals to detect damages occurring in structures. The signal processing method is one of important means for structural damage detection based on vibration response signals, its purpose is to extract small changes in vibration signals to identify and quantify damage’s levels in structures. S transformation is a short time Fourier transformation (STFT) with a variable window or an extension of wavelet transformation (WT). Here, in a test, a concentrated load was exerted at the middle of a simply supported RC beam with the stepwise equal amount loading method. The vibration response signals after each step unloading were collected using a hammer excitation. Then the vibration data of the RC beam before damage and after damage were processed with S transformation. The test results showed that the obtained time-frequency spectra of the vibration signals and their time-frequency spectral energy E after using S transformation qualitatively and quantitatively describe crack’s developing at the middle position of the simply supported beam with increase in load, the energy attenuation step by step during elastic wave passing through, and the energy significant increase during the beam being completely destroyed; the effectiveness and feasibility of S transformation method for damage recognition of simply supported beams under different load conditions are also verified.
  • YIN Tingting1, DENG Zichen1,2, JIANG Xianhong1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 168-172.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Taking dynamic problems of some large stiffness and small size adapting pieces in complex spatial structures before on-orbit assembly as studying background, the orbit-attitude coupled dynamic model for spatial rigid beams was established. With this dynamic model, the symplectic Runge-Kutta method was adopted to simulate dynamic behaviors of a spatial rigid beam. From the obtained numerical results about evolution processes of the beam’s orbit radius, true anomaly and attitude angle, it was shown that with increase in initial attitude angular speed, the orbit-attitude coupled effects become more obvious; the relative error of the system total energy within each time step is recorded, all relative errors are compared with those in the numerical results using the classic Runge-Kutta method, the correctness of the numerical results using the symplectic Runge-Kutta method and the long-time numerical stability of the symplectic Runge-Kutta method are verified.


  • WANG Haitao WANG Kun SHI Lichen
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 173-179.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To extract effectively features of different damage levels on rolling bearings’ inner race, a method of quantitative fault feature extraction based on the combination of Volterra kernel function theory and bi-spectral analysis was proposed. Firstly, input signals and output ones of a system were used to determine a Volterra model. Secondly, Volterra kernel function of the model was solved with the improved multi-pulse excitation method. The model was identified using the generalized frequency response function (GFRF). Finally, using the means of bi-spectrum and its slices, the information of damage level features implied in the second order kernel function due to phase coupling was separated, quantized and extracted. A rolling bearing test table was used to collect faulty bearings’ data to verify the proposed analysis method. The results were compared with those using the envelope spectral analysis method. The results showed that the bi-spectral slice method can be used to intuitively and quantitatively express the information implied in Volterra second order kernel function when there are not obvious shock vibration, and effectively distinguish normal bearings and faulty bearings with different inner race damage levels.
  • WU Yudong, LI Renxian, DING Weiping, YANG Mingliang, MA Yifei
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 180-184.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The similarity between vibration reduction frequency band features of torsional vibration dampers (TVDs) and local resonance photonic crystals band gap ones was discussed with the dynamic equivalent moment of inertia analysis. A new method to calculate TVDs’ vibration reduction frequency band gap was proposed based on the theory of local resonance photonic crystals. The influences of TVDs’ geometric parameters and material ones on their vibration reduction band gaps were studied. Aiming at a certain multi-purpose vehicle (MPV)’s interior booming noise problem caused by its powertrain torsional vibration, this method for calculating vibration reduction frequency band gap was used to design a TVD. It was manufactured and installed in the MPV. The MPV’s powertrain torsional vibration tests and vehicle interior noise tests were conducted. The results showed that this TVD can effectively suppress the MPV’s powertrain torsional vibration, reduce its interior booming noise and improve the whole vehicle’s NVH performance.
     
  • KANG Zhuang,NI Wenchi
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 185-189.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    At present, the vortex induced vibration (VIV) studies are mainly focused on circular cylinders fixed elastically with one DOF or 2-DOF to analyze change laws of their amplitude, frequency and phase etc. vibration responses with variation of the reduced velocity. For the VIV considering rotational-DOF, the relevant studies are not many due to the restriction of test devices and detection methods. Here, based on the software OpenFoam, the VIV response features of circular cylinders with a lower mass ratio and rotational-DOF were simulated numerically. Firstly, according to Williamson (2004)’s test, the VIV response of a cylinder with two-DOF was simulated, then a rotational-DOF was added and the similar numerical simulation for this cylinder under the same boundary conditions was conducted. Through the contrastive analysis of these two VIV responses, it was concluded that the cylinder’s yaw phenomenon occurs in its VIV process; at the same time, the yaw phenomenon slightly suppresses the VIV amplitude; in addition, the yaw frequency is equal to the cylinder’s lateral vibration frequency, and the yaw amplitude is related to the form of tail vortex.
  • ZHONG Xianyou,TIAN Hongliang,ZHAO Chunhua,CHEN Baojia,CHEN Fafa
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 190-195.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The effect of fast kurtogram to extract rolling bearings’ weak fault signals is not obvious under interference of strong background noise. Here, rolling bearings’ weak fault feature extraction was conducted with the combination of iterative filtering and fast kurtogram. The faulty bearing’s vibration signals were adaptively decomposed into a group of intrinsic mode components with iterative filtering. The iterative filtering method was used to denoise rolling bearing’s vibration signals with strong noise. An optimal band-pass filter was constructed using the fast kurtogram.Finally, the envelope spectra of the filtered signals were compared with fault feature frequencies of rolling bearings to judge the diagnosed bearing’s fault types.The effectiveness and advantages of the proposed method were verified with numerical simulation and tests.

  • LI Rui1 LI Xiaozhang1 ZHENG Xianglong2 ZHOU Yitang1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 196-201.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The Frequency method is widely used to measure tension of hanger rods in arch bridges. But, the traditional frequency method ignores the effects of bending stiffness. When it is used to calculate tensions of hanger rods with two fixed ends, the calculation error is too large to meet requirements of engineering accuracy. Here, the frequency equation of a hanger rod with two fixed ends was deduced with its dynamic equation. Then the particle swarm optimization (PSO) method was adopted to solve this transcendental frequency equation. Finally, two order natural frequencies measured of the hanger rod were employed to realize accurate recognition of tension and bending stiffness of the hanger rod. Through identifying tension of a virtual hanger rod and error analysis, the recognition accuracy of the proposed method was verified. Through identifying tension of an actual hanger rod, the engineering feasibility of the proposed method was verified.

     
  • Wang Xue-Qing1, Zhao Tong-Wu2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 202-207.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The energy transmission in percussive machines’ penetration process is a key problem of percussive systems. Here, for general percussive penetration systems with a single cylinder piston, the expression of energy transfer efficiency for a percussive system with a single cylinder piston was derived. Furthermore, the dual energy conversion process and residual energy in piston and tools were presented with the wave theory. Influences of system parameters on energy transmission were analyzed. The study showed that in the dual energy conversion process, the system penetration efficiency η is a product of the incident wave effective conversion efficiency and the penetration conversion efficiency; there is an optimal region for η (η>75%) when the system constant q=0 and 1<θ<2.5; the residual energy is lower when q≥0, but it increases rapidly with decrease in q when q<0; increase in the residual energy affects normal operation and fatigue life of a percussive system. Taking tests on a percussive energy transmission test system as examples, the results of calculation agree well with those of tests.



  • WU Guan-nan, XU Chao
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 208-213.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Under severe loading conditions, bolted joints in assembled structures may loosen or fail. Reliability detection for early looseness in connection positions is significant to ensure the reliability and safety of structures. Here, high-frequency ultrasonic signals with a chaotic feature were adopted to excite a connection structure to be detected to acquire dynamic response signals of the structure, and use the nonlinear time series analysis method to extract feature parameters to characterize bolt looseness. Taking a typical bolted lap beam as the study object and piezoelectric ceramic pieces as units to collect excitation and response signals, the structure’s response signals were demodulated and reconstructed in a phase space. Lyapunov dimension to characterize an attractor’s whole features and ALAVR to reflect an attractor’s local features were extracted and taken as looseness indexes. Test results showed that the proposed method can effectively detect the looseness state of bolted joints; compared with Lyapunov dimension, an attractor’s feature parameter ALAVR can better detect the decline of pre-tightening force in bolts, ALAVR can effectively detect early bolt looseness.
  • JIANG Zhong-tao1, LI Ye2, PANG Xue-jia3, WANG Shi-ping1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 214-220.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on the coupled Euler-Lagrange (CEL) algorithm in the software ABAQUS, processes of near field underwater explosion bubble jet load impacting hull plates were simulated. The numerical results of CEL algorithm agreed well with Obara’ test ones, so the effectiveness of the numerical method was verified. Then, the load pressure characteristics of underwater explosion jet, jet velocity distribution features and the distribution features of structural shear stress induced by jet were investigated. The results provided a reference for the anti-impact design of hull plates against underwater explosion jet load in practical sea-battles.


  • HE Zhao-qi1XUE Dong-xin1Zhang Juan2SONG Xi-geng1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 221-229.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The classical closed-loop dynamic model built with Newton-Euler approach for a 6-UPS Stewart platform has some shortcomings. It was improved by some scholars in three aspects including considering rotational DOF of rods around their axis, modifying restraint moment direction of universal joint and adopting the parallel axis theorem to calculate moments of inertia of each structure. Here, Euler equations for rods and upper platform were established according to reasonable forms of the momentum moment theorem, based on torque balance of upper rods about a lower hinge point and that of lower ones about the same hinge one being different cases. Finally, two different closed-loop improved dynamic models were deduced combining the above three aspects. Using the same example, the necessity of improving the model was explained by comparing dynamic responses of the improved models with those of the original model. It was shown that from the view point of theoretical derivation, the improved models are more reasonable and more accurate than the original one be.



  • SUN Feng,ZHOU Ran,XIA Peng-peng,JIN Jun-jie,XU Fang-chao, LI Qiang,JIN Jia-qi
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 230-233.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Permanent magnetic suspension systems with controllable magnetic circuit have characteristics of strong nonlinearity and large difficulty in control. According to the characteristics of a permanent magnet suspension system, a cascade controller composed of an angle loop and a position loop was designed here. A permanent magnetic levitation system was simulated and tested with this controller. The test results showed that the system has a good robust stability; the system can track an input displacement signal within a short time and reach a new stable suspension state when a smaller step external disturbance is exerted on the system.


  • HONG Xinchen 1,2 PAN Minghui 1 YUAN Yinan 1 WANG Yalei 1 WU Shasha 1 LAN Siren 1,2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 234-238.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Here, the relation between physical quantities to represent a bamboo garden space’s soundscape and psychological quantities to represent human subjective feelings was explored. The semantic difference method was used for observers to evaluate the coordination degree of different sounds and sights in a bamboo space, the objective physical indexes of observers’ positions were measured, and eventually the evaluation model for bamboo gardens’ soundscape coordination degree was established from the perspective of the soundscape ecology and the psychophysics. The results showed that when geophysical sounds are lighter, they make evaluators produce more coordinated perceptions or general coordinated ones, while their sound pressure levels rise, evaluators produce a certain uncoordinated feeling; biological sounds make evaluators produce a steady and coordinated sensation, while their sound pressure levels rise, evaluators  don’t have a significant uncoordinated feeling; artificial sounds make evaluators produce a more uncoordinated feeling; the fitting trend for subjective data and objective ones of various acoustic elements conform to principles of the psychophysics, geophysical sounds and biological ones conform to Fechner's law, artificial sounds conform to Stevens' law; the proposed evaluation model is suitable to bamboo gardens’ soundscape coordination degree, it provides a reference for scientific and reasonable construction of bamboo gardens.
     
  • WU Bobo,WANG Gaoyi,LI Haixia,REN Zhongyi,HAN Ximing
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(9): 239-242.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In order to investigate effects of reflector on insertion loss of a U-beam’s adhesive sound-absorbing material, an analog reflector was constructed for tests based on the outline of a train car. The test results were analyzed using the sound line theory. It was shown that when a reflector exists, noise within medium and high frequency ranges after repeated reflections between reflector and a U-beam’s adhesive sound-absorbing material gradually dissipates energy, the insertion loss increases; in the noise sensitive area outside the U-beam, the insertion loss during reflector existing is significantly larger than that be during absence of reflector; the 1/3 octave insertion loss curve for each measured point reveals the existence of reflector has a larger influence on noise within medium and high frequency ranges but a less influence on noise within a lower frequency range. This study provided a reference for evaluating the actual noise reduction effect of a certain newly developed adhesive sound-absorbing material used at the inner side of a U-beam’s web.