15 August 2018, Volume 37 Issue 17
    

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  • WANG Qiongyao1,JIANG Kaihong2,RAKHEJA Subhash1,SHANGGUAN Wenbin1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 1-8.
    Abstract ( 365 ) Download PDF ( 169 )   Knowledge map   Save
    A 3-D liquid slosh dynamic model was established for a liquid-partially filled tank truck in course of rotating or braking. The validity of this model was verified through comparing the calculating results obtained using this model with those obtained using tests and a quasi-static model. Both of them agreed well. The effects of geometry parameters including holes’size,shape and location of a wave cutter on load shifting and sloshing force when liquid sloshed transiently were studied. Forces acting on tank end face and individual wave cutter were evaluated under various geometry parameters of wave cutters. Large air pressure on wave cutters,tank end face and confined space between wave cutters was found under medium or high liquid-filling ratios. The results showed that geometry parameters of wave cutters have large effects on liquid load shifting,slosh forces and pitch moment; air pressure can reduce longitudinal liquid load shifting to suppress liquid slosh and improve the braking performance of the tank truck.



  • XIE Lanbo1,LIAO Haili2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 9-15.
    Abstract ( 240 ) Download PDF ( 185 )   Knowledge map   Save
    The calculation formulas for lateral galloping critical wind speed and amplitude of prisms with wind attack angle were deduced with the quasi-steady theory. H-shaped columns were adopted to conduct wind tunnel tests and calculations. The results showed that the galloping critical wind speed calculation results using the proposed method are very close to those using Den-Hartog formula under smaller wind attack angles; under larger wind attack angles,the difference between the two results is bigger,so Den-Hartog formula can’t be used to do galloping calculation under larger wind attack angles; the results of theoretical calculation for galloping amplitude agree well with those of tests,the correctness of the proposed method is verified.



  • CHANG Binquan1,YAN Changfeng1,YUAN Hao1,3,KANG Jianxiong1,2,WANG Kai1,WU Lixiao1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 16-24.
    Abstract ( 359 ) Download PDF ( )   Knowledge map   Save
    A 2-DOF dynamic model for rolling bearings was built to reveal their vibration response mechanism more correctly due to their inner race surface existing localized defects under action of radial loads. The process of rolling elements entering defective area until leaving was described as four events including entry event,impact one,exit one and load compensation one. Appropriate excitation force functions were constructed according to the corresponding events. Considering the effects of time-varying displacements due to defects and bearing’s stiffness-varying vibrations on bearing’s dynamic characteristics,based on Hertz contact theory,the dynamic model for a bearing with local defects was established. The fourth-order Runge-Kutta method with varying steps was used to solve the dynamic equation and obtain the model’s vibration response signals. The effect laws of defect size and rotating speed on bearing system’s vibration acceleration amplitude were investigated. The validity and feasibility of the dynamic model were verified using faulty bearings’tests.
     
  • SONG Xijie,LIU Chao,YANG Fan,ZHA Zhili, CHU Changhong, ZHANG Chongyang
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 25-31.
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    From the perspective of inlet vortex affecting pressure pulsation in an axial flow pump,the influence mechanism of inlet vortex on the axial flow pump was investigated using pressure fluctuation feature tests. Pressure pulsation sensors were installed at impeller inlet,impeller outlet and guide vane outlet. Pressure fluctuation tests were conducted under three typical operation conditions and the development process of inlet vortex was clearly captured using a high speed camera. The results showed that the amplitude of pressure pulsation under a small flow rate condition is the largest at one measured point of the axial flow pump device; the amplitude of pressure pulsation decreases gradually with increase in flow rate; the pressure pulsation excitation source in impeller inlet area is impeller rotating; pressure pulsation in impeller outlet area is caused due to the interaction between guide vane and impeller; pressure pulsation in guide vane outlet area is mainly influenced by outlet circulation; under a large flow rate condition,inlet vortex is developed to enter impeller area,increase the instability of flow field inside impeller and affect pressure pulsation inside impeller; the inlet vortex frequency is the blade passing one to be easy to cause the whole unit’s resonance.
  • WU Tianhao 1,2,3, FU Shixiao 1,2,3, REN Tongxin 3, HE Yue 3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 32-40.
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    Freely hanging water intake risers (WIRs) are widely used in deep-sea oil and gas development for its economic efficiency. Due to interaction between vessel motion and internal flow,WIRs have strong dynamic responses in inline (IL) direction and form a relative oscillatory current between them and surrounding water. This oscillatory flow is very likely to induce vortex-induced vibration (VIV) of WIRs in cross flow (CF) direction. Here,large-scale model tests for a freely hanging water intake riser (WIR) were performed in an ocean basin to investigate the riser’s dynamic responses under interaction between vessel motion and internal flow. In tests,fiber brag grating (FBG) strain sensors were used to record strain time histories of some points at the riser surface in CF and IL directions. The results showed that large diameter WIRs’VIV occur under actions of internal flow and oscillation flow field; within the internal flow speed range of tests here,the action of internal flow can be neglected,the vessel motion-induced VIV has an instability.


  • WANG Zhiwei1,2,3,LIU Yuanzhen1,2,3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 41-47.
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    The influences of packages’jumping and cushion material nonlinearity on acceleration responses of packages were investigated with tests. Under random vibrations,acceleration response features of packages were analyzed in frequency domain and time domain. Results indicated that under Gauss excitation,package jumping was the main reason to cause packages’acceleration responses having non-Gaussian features. Under unconstrained conditions,packages have obvious jumps,their acceleration responses’probability density distribution is a non-Gaussian one; under elastic and fixed constrained conditions,jumping of packages is restricted,when the vibration intensity is larger,acceleration responses’distribution of packages deviates from Gaussian distribution to some extent,when the vibration intensity is smaller,acceleration responses’distribution of packages is a Gaussian one.


  • CHENG Can 1 LI Jianyong 1,2 XU Wensheng 1,2 NIE Meng 1,2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 48-55.
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    To improve the accuracy of tools’wear recognition under the case of small samples,a tools’wear recognition method based on support vector machine (SVM) and particle filtering was proposed. Aiming at difficult problems of SVM’s feature selecting and parametric selecting,a bi-level programming model for SVM’s input features and parametric optimization was developed and solved using the genetic algorithm and the artificial bee colony algorithm. Then,the particle filtering method was used to modify tools’wear recognition results obtained using the regression algorithm of SVM. Test results showed that under the case of small samples,the tools’wear recognition method based on SVM and particle filtering has a good learning capability and can recognize tools’wear precisely.

  • CHEN Ruilin,DONG Qi
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 56-62.
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    Using the nonlinear finite element software LS-DYNA,a flange connection structure’s 3D finite element model was built. The nonlinear coupling among a flange disk,a bolt connection and a flange gasket was realized using the penalty function method. The pre-tightening force loading of bolt connection was realized using the temperature load method. The ALE multi- matter fluid-solid interaction algorithm was adopted to study the dynamic response characteristics of a flange structure under blast impact loads. The effects of shock wave’s incident angle,bolt connection’s pre-tightening force and flange gasket’s thickness on a flange connection structure’s dynamic features were studied considering flange gasket being alloy steel and rubber under the action of blast impact loads. The results showed that flange disk is the main energy-dissipation component; bolt connection is mainly affected by incident angle of shock wave; effects of shock wave’s incident angle on an alloy steel flange gasket are smaller; under the action of high pressure compression wave,the flange disk produces non-uniform compression deformations relative to bolt connection; a thicker flange gasket is not always better than a thinner one be,reducing properly flange gasket’s thickness can improve the anti-impact capacity of flange connection structures.


  • SUN Yuan1,YANG Feng1,ZHENG Jing2,XU Maoxuan1,PEI Shuojin2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 63-71.
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    In order to solve problems of slower convergence and lower separating performance of the existing blind source separation methods,a new method based on membrane computing (MC) and particle swarm optimization (PSO) was proposed. The separated signals’neg-entropy was taken as the fitness function of PSO. Particles were uniformly distributed into each elementary membrane. The velocity and position of population particles were updated with a particle own optimal position and the population global optimal position. The optimal solution to PSO was used to adjust step function of blind source separation and then separate signals. The proposed algorithm simplified inertia weight’s choosing to ensure the accuracy of PSO local search and satisfy the variety of global search. The simulation and actual application showed that mixing signals can be well separated with this new method and the premature convergence problem of PSO can be avoided; this new method has a faster convergence speed and a more excellent separating performance.
     
  • HE Wenfu,HUANG Yishen,LIU Wenguang,LIU Wenyan
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 72-78.
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    Aiming at rubber bearing mechanical performances’coupling features related to horizontal loading,horizontal deformation and vertical loading,tests for relevance between horizontal and vertical performances of rubber bearings were conducted. Here,considering rubber supporting bearings with a multi-factor coupled mechanical model,the dynamic responses of a nuclear plant isolated structure under 12 waves with different shear wave velocities were simulated and analyzed. The theoretical analysis results agreed well with those of tests. The simulation results showed that the vertical stiffness decay of AP1000 is larger than its horizontal stiffness decay; different earthquakes with different shear wave velocities have large influences on the dynamic responses of the nuclear plant isolation structure,the smaller the shear wave velocity,the larger the stiffness decay rate in both directions; the displacement response of the super-structure of the isolated structure supported by rubber bearings with the coupled model is significantly larger than that supported by bearings without the coupled model; under earthquake beyond design basis,the isolated structure’s displacement response and stiffness decay rate have abrupt changes,bearings with the coupled model enter a buckling failure stage and the  superstructure enters sudden collapse; therefore,under earthquake beyond design basis,if a nuclear plant isolated structure’s dynamic responses are computed not using rubber bearings with the multi-factor coupled mechanical model,its seismic responses can be under-estimated.
  • ZHANG Yuliang1,YANG Fei1,YUE Honghao1,DENG Zongquan1,XU Yang2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 79-85.
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    Based on the dynamic load identification principle in the frequency domain method,impact loads of a connection-separation device between satellite and rocket driven using shape memory alloy (SMA) were identified for three times. The EEMD algorithm was used to de-noise and identify impact response signals of measured points,and then three times of impact loads generated in separation process were identified. The test results showed that the frequency domain method based on EEMD can be used to more accurately identify three times of impact loads of the connection-separation device between satellite and rocket with a better recognition effect,the feasibility and correctness of the proposed method is also verified with test results.
  • LI Chunguang,HUANG Jingwen,ZHANG Ji,HAN Yan
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 86-92.
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    A cable-stayed bridge with a side girder steel-concrete composite beam was taken as engineering background,Based on the side girder section-model’s wind tunnel tests,the vortex-induced vibration (VIV) performances of this blunt shaped composite deck were investigated and reasonable aerodynamic optimization measures were proposed. The test results showed that the open section girder of the side girder composite beam is easy to have vortex induced resonances under the condition of lower wind speed,and its VIV performances gradually get worse with decrease in wind attack angle; aerodynamic optimization measures make the effect of an outside horizontal stabilizer at the bottom of the side girder be better than that of inside  horizontal stabilizer; a vertical stabilizer installed at the bottom of the side girder can suppress the vertical VIV to some extent,but it causes the girder’s torsional VIV rising; the anti-vortex effect of a flow suppression board at the overhauling railing top is better than that of a horizontal stabilizer at the bottom of the side girder,so the superstructure of the side girder has a more significant influence on its VIV performance; wind fairings installed at both sides of the side girder have a best anti-vortex effect,the suppression rate of VIV amplitude can reach 80%.


  • ZHANG Jiayan1,2, MENG Qingxi1, FENG Xugang1,WANG Bing1,HU Xuefeng1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 93-100.
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    Mould oscillation control is the key link of continuous casting. Based on the hydraulic control system with nonlinear time-varying and uncertainty model structure characteristics,a compound control solutions on iterative learning mould hydraulic vibration was proposed. The PID(proportion integration differentiation controller) controller with displacement transducer constitute the disturbance-resisting inner loop system. The iterative learning controller (iterative learning controller,ILC) unit constitute the mould hydraulic vibration system as outer loop,to ensure the system tracking performance. Through the electro-hydraulic system design calculation and MATLAB simulation analysis,the effect of dynamic tracing control scheme at ILC was tested. On this basis,it was used in real control operation. Results show that the control scheme has  good effect such as strong robustness and good dynamic performance.
  • HE Dong-tai GUO Yu WU Xing LIU Zhiqi ZHAO Lei
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 101-106.
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    Aiming at problems of planet gear bearing’s vibration signals having time-varying transmission path and these signals being obliterated by gears meshing vibration signals,a diagnosis method for a planet gear bearing’s inner race faults based on self-reference adaptive de-noising (SRAD) was proposed here. Firstly,the disturbances of gears meshing vibration signals were weakened with the technique of SRAD and the pre-whiten technique of AR model. Then,the resonance band’s parameters were solved adaptively based on the spectral kurtosis approach. Furthermore,the square envelope signal was extracted using Hilbert transformation. Finally,the spectral analysis was conducted for the envelope signal. Test results showed that the proposed method can effectively reveal the fault feature information of planet gear bearing’s inner race.

     
  • LI Zhiwen 1,2, LI Jianchun 1, HONG Shengnan 1,2, LI Haibo 1, ZHANG Guokai 1,2,3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 107-114.
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    Due to geometric diffusion of wave fronts and absorption of medium,amplitude and frequency of blasting seismic waves have a series of changes in their propagation process. In order to study generation and propagation laws of blasting seismic waves,rock mass was considered as a viscoelastic medium,blasting loads were equivalently exerted on the boundary of the vibration zone,the integral solution to the problem was obtained in frequency domain. The numerical calculation and parametric analysis were done for the integral solution. The results showed that the shorter the rise time of blasting loads,the larger the boundary vibration amplitude of the vibration zone; the longer the duration for blast loads lasting,the longer the duration for the boundary vibration lasting,but the vibration amplitude is not influenced; under the action of the same blasting loads,the smaller the medium’s elastic modulus and viscosity coefficient,the larger the boundary vibration amplitude; geometric decay of blasting seismic waves is divided into near-field attenuation and far-field attenuation,the decay rate of near field is obviously larger than that of far field; with increase in the ratio of viscous coefficient to elastic modulus,medium absorbs blasting seismic waves more obviously; with increase in the propagation distance of blasting seismic waves,their higher frequency components decrease  relative to their lower frequency components,the larger the viscosity coefficient,the faster the decrease speed. 
  • LIU Jian CHEN Junhuang XIA Baizhan MAN Xianfeng
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 115-121.
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    The traditional optimization design of photonic crystal is based on a deterministic acoustic model. However,uncertainties widely exist in photonic crystal and seriously affect its acoustic properties. Here,an interval model was introduced to describe uncertainties of its system parameters. Then,Chebyshev polynomial was employed to construct the surrogate model of energy band structure of photonic crystal to analyze influences of uncertain parameters on photonic crystal’s bandgap. Finally,taking photonic crystal bandgap’s maximization as the objective function,taking bandgap variation range as the constrained condition,the interval photonic crystal reliability optimization model based on Chebyshev surrogate model was constructed. The genetic algorithm was used to solve this optimization model. Numerical results showed that Chebyshev surrogate model can effectively and accurately predict the bandgap variation range of photonic crystal based on the interval model; when interval uncertainties are considered,the optimization model of photonic crystal based on Chebyshev surrogate model can maximize the bandgap variation range to significantly improve the sound shielding performance of photonic crystal.
  • QIN Yi 1, 2 ZHANG Qingliang 1, 2 ZHAO Yue 1, 2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 122-127.
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    Since fault features in planetary gearbox vibration signals are usually submerged in noise signals,it is necessary to study how to extract these weak fault features. Aiming at the problem of traditional feature extraction method based on the singular value decomposition (SVD) being not able to automatically select the amount of effective singular values,a new fault diagnosis method for planetary gearboxes based on adaptive SVD was proposed. Firstly,according to a certain condition,several different amounts of effective singular values were selected with the proposed method to get several reconstructed signals. Secondly,the optimal reconstructed signal was automatically chosen according to the skew absolute values of these reconstructed signals. At last,the envelope analysis was done for the optimal reconstructed signal to acquire the envelope spectrum of the fault signal. The contrastive results between simulation and tests showed that compared to the traditional feature extraction method based on SVD,the proposed method can better de-noise and extract weak fault features in planetary gearbox vibration signals.

  • CHEN Xudong, LIU Zhiheng, CHEN Chen
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 128-134.
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    There are still some problems in test technique of concrete material’s SHPB dynamic flexural and tensile tests. According to the assumption of stress equilibrium,it is necessary to know specific values of three kinds of stress waves to calculate stress and strain rate. However,the time required for longitudinal propagation of stress wave along a specimen is shorter than that for lateral propagation. Thus,stress wave can’t be measured on a transmission rod when the specimen is broken. According to the results obtained by Delvare et al,the calculation formula for bending moment can be derived using an infinite long beam model to further calculate the specimen’s strength and strain rate. In addition,in impact,bending and tensile tests,inertial forces exerted on the specimen affect the test accuracy. So,it is necessary to discuss inertial forces exerted on the specimen. Here,in impact tests,only part length of the specimen produced deformation. This part length was defined as the valid length. The relation formulas of the infinite long beam model were used to derive the calculation formula of the valid length. According to the correlation principle,inertia forces exerted on the specimen were calculated,and then the specimen’s actual strength was calculated.
  • FANG Deping
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 135-140.
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    Symmetric and antisymmetric vibration modes of an ordinary continuous beam were taken as vibration modes of a 2-span externally prestressed continuous beam,the 1st and 2nd order deformations of external tendon were precisely analyzed. Based on the energy method,the natural frequencies of the externally prestressed continuous beam were calculated. The calculation results indicated that external precompression force has the compression softening effect,this effect can be expressed using an influence coefficient with the range of 0—1; the influence coefficient value is determined by the number of deviators; if there are no deviators within a span,the influence coefficient is 1; the compression softening effect of external precompression force is the same as that of external axial force; if the number of deviators increases,external tendon is gradually close to unbonded one,the influence coefficient gradually drops from 1 to near 0,the compression softening effect of external precompression force is close to zero effect of unbonded precompression force; if there is at least 1  deviator within a span,the influence coefficient is much less than 1,the compression softening effect of external precompression force can be neglected; if the eccentricity and area of external tendon increase,only the natural frequency of the beam’s 1st order symmetric vibration shape increases obviously,the effects of external tendon on natural frequencies of the beam’s all antisymmetric vibration modes and symmetric ones except the 1st order one are negligible.
  • YU Qingbo,YANG Guolai,GE Jianli,SUN Quanzhao,XIAO Hui
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 141-147.
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    Considering excitation action of barrel vibration on motion form of projectile in its inner-ballistic period,the finite element dynamic model for the mutual coupled problem between projectile and barrel based on the vibration theory was built. The user-defined subroutine was utilized to realize projectile dynamic process related to propellant combustion law under module charge,and realize the actual loading conditions varying with projectile motion during propellant gas pressure acting on barrel inner-wall,and solve the problem of gases pressure radial effect’s inaccurate loading or being unable to load in previous simulation. The curve comparison between test data and simulation results under the same shooting conditions was obtained. The barrel’s dynamic response time history curves under different simulation conditions were also gained. The results showed that the established nonlinear dynamic model can better reflect the actual artillery firing condition; it can more actually reveal barrel structural dynamic response process; it provides reference data closer to reality for artillery design and fault analysis.



  • WANG Dongming, GAO Yongwu
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 148-154.
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    Here,16 strong ground motion records for Ms 7.0 Lushan and Jiuzhaigou Earthquakes were selected with screening conditions of epi-central distance being less than 55 km and PGA being larger than or equal to 50 gal. 41 kinds of ground motion intensity parameters and accumulative kinetic energy curves based on V2 time-frequency response spectrum (V2TFRS) were extracted from each of the selected records. 111 lumped mass simplified models were established to do elastoplastic time history analyses with the selected 16 records taken as inputs,and extract the maximum inter-story drift angle and the maximum peak floor acceleration at the lumped mass of each building.  Taking the limit value of inter-story drift angle as a building’s damage state parameter,damage states of 111 buildings under the action of each of the 16 selected records were obtained. Through comparing 41kinds of ground motion intensity parameters and accumulative kinetic energy curves based on V2TFRS of Ms 7.0 Lushan and Jiuzhangou earthquakes’ground motion records as well as damage states of 111 buildings,the reason why Jiuzhaigou earthquake had a smaller destructive capacity than Lushan earthquake did was described quantitatively to provide a basis for scientifically analyzing the disaster difference between Lushan earthquake and Jiuzhaigou one.
  • ZHANG Yibei1,GAO Jifeng1,CHEN Wujun1,ZHANG Daxu1,FANG Guangqiang2,CAO Zhengli2,PENG Fujun2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 155-160.
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    A large space deployable truss made of weave composite material was taken as a study object. Modal tests in microgravity environment and simulation analysis were conducted for this truss. The space truss was mainly composed of circular hollow section pipe,triangular spacer and oblique stiffened cable. In modal tests,a pneumatic electromagnetic suspension system was used to realize a structure’s gravity off-loading and simulate the microgravity environment. In simulation analysis,a circular hollow section pipe made of weave composite material was assumed to be an orthotropic material structure; a triangular spacer made of laminated composite material was assumed to be an isotropic material structure; the effects of oblique stiffened cable’s pre-stress on structural stiffness and oblique stiffed cable’s equivalent elastic modulus were considered. The simulation results agreed well with those of tests. The study results provided a reference for studying large pre-stressed space deployable trusses.
  • LI Zhen,LI Weiguang,ZHAO Xuezhi,LIN xin
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 161-168.
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    The matching pursuit (MP) algorithm is usually used to realize signals’sparse decomposition. In the classical MP algorithm,the criterion for selecting the optimal core function is that the primitive function and the core function have the largest inner product. However,this criterion may cause reconstructed signals to have large error. Aiming at this problem,the iterative residual criterion was proposed. Many examples showed that this criterion causes reconstructed signals to have a smaller error. Meanwhile,the endpoint effect was detected in both the classical MP algorithm and the iterative residual algorithm to cause reconstructed signals having a larger error at an endpoint. In order to solve this problem,an extension algorithm based on polynomial fitting was proposed. Example results showed that this algorithm is more effective than the iterative residual algorithm be to weaken the endpoint effect.
  • ZHANG Hao1,2,LI Hongnan1,3,CAO Guangwei1,SHANG Bing4
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 169-177.
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    In order to investigate the effects of strain rate on nonlinear seismic disaster process of RC structures under earthquake,using the uniaxial dynamic constitutive relations of reinforcement and concrete and their loading and unloading regulations,a material subroutine of ABAQUS explicit dynamic analysis based on the fiber beam theory was developed. Numerical simulation with this subroutine for a three-story RC frame-shear wall structure’s shaking table test was conducted to verify the correctness and effectiveness of this subroutine applied in RC structures’nonlinear seismic response analysis. The simulation for progressive collapse damage process of a RC structure considering strain rate effect was realized by defining failure damage criteria of reinforcement and concrete in the material subroutine. The progressive collapse damage modes of the shaking table test’s model structure and the RC frame structure were predicted,respectively. The effects of strain rate on the seismic response and progressive collapse damage process of the RC structure were preliminarily discussed. The results showed that the developed subroutine can correctly simulate the nonlinear seismic disaster process of RC structures,and it can be applied in RC structures’aseismic design and analysis considering strain rate effect.



  • CHENG Xiefeng1,2,SHE Chenjun1,LI Ji1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 178-184.
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    Aiming at chaotic characteristic difference between a normal heart sound signal and a pathological one,an anti-control method for heart sound chaos making the pathological heart sound track the normal one was put forward. Here,firstly,the design principle and standard for the heart sound chaos anti-control method were proposed. Then,a heart sound chaos anti-control method combining TD and Fuzzy-PID control theories was designed. When pathological heart sounds were input,the control method adjusted PID parameters according to the normal heart sound read from the other path to make the former rapidly trace the latter. The test results and quantitative analysis showed that the proposed control method has the advantages of fast tracking speed,small error and good robustness; the controlled pathological heart sound signal can trace the normal one well and its chaotic characteristics are obviously enhanced; this heart sound chaos anti-control method can be used to develop the related medical auxiliary physiotherapy equipment of cardiovascular disease with feasibility and practicability.

  • YANG Jing1,WU Rongkun2,PENG Yu1,LI Hua2,PIAO Mingwei1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 185-195.
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    To correctly analyze inner forces in a 2-vehicle set system for piggyback transport,the relevant simplified processing technique strategies were proposed and validated for complex surfaces’contact friction problems. The multi-body system’s dynamic simulation analyses indicate that a tare or laden vehicle can realize 3 equilibrium states of trunnion axe locking,rolling track bearing and ground support and their load-transfer path changes so as to sufficiently guarantee 100 % Ro-Ro operations in road-rail transit of freight trucks or semi-trailers of containers; a topological relation graph of complex constraints is used to improve the modularization of system modeling or the modeling level of templates; based on the full correctness validation of the simulation model,the rigid-flexible coupling simulation technique is used to deeply study the effect laws of deformation compatibility,structural stability and the relevant factors,and provide necessary technical supports for optimal design of lightweight vehicle bodies; the local high stresses and their alternative changes are taken as one of important criteria to determine structural damages,so inner force features of relevant constraints should be analyzed using the rigid-flexible coupled simulation,not confined to the geometric space field.
  • LI Li,ZHANG Zuyan,XU Ningbo,YI Yongzhi
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 196-203.
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    According to vibration characteristics of FDZ-type dampers’hammer,based on the theoretical calculation model of FR-type dampers,considering 6-DOF of the hammer in six directions,the theoretical calculation model of FDZ-type dampers was established. This theoretical model was suitable for all kinds of Stockbridge-type dampers. Through FDZ-type dampers’vibration-exciting tests,the power characteristic curve obtained using the theoretical model was compared with that acquired in the vibration tests. It was found that power peak,peak frequency,trend of curve and position of peaks and troughs of both curves agree well with each other,and the correctness of the theoretical model is verified; the model can be used to calculate breeze-induced vibration responses of transmission lines,and it provides a theoretical basis for anti-vibration design of transmission lines.

          
  • WU Lei DU Qungui XIAO Longfan
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 204-209.
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    Pressure roller mechanism is one of key mechanisms in a corrugating machine. It plays an important role in bonding corrugated base paper and core one. The vibration of pressure rollers not only affects the forming quality of corrugated boards but also reduces the working life of a corrugating machine. It also causes a lot of noise. Here,based on a simplified pressure roller mechanism model,its dynamic model was established. Natural frequencies of the pressure roller mechanism were solved using Lagrange equation to provide a theoretical basis for optimization of the mechanism. A vibration test was conduct for the pressure roller mechanism to verify the correctness of its dynamic model. Finally,its natural frequencies were increased to avoid resonance by changing factors to affect natural frequencies of the pressure roller mechanism.


  • MA Zengqiang,ZHANG Junjia,ZHANG An,RUAN Wanying
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 210-217.
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    Aiming at problems of early fault features of rolling bearings being weak and the deficiency of the frequency sliced wavelet transformation (FSWT)’s extracting fault features under strong background noise,a new fault feature extracting method using FSWT and joint de-noising of the variational mode decomposition(VMD) and the singular value decomposition (SVD) was proposed. Firstly,VMD was used to decompose adaptively a fault signal into a series of intrinsic mode functions (IMFs). Some IMFs containing richest fault information were selected to reconstruct a signal based on the kurtosis criterion. Then SVD was used to de-noise the reconstructed signal again and improve its signal-noise ratio. Finally,FSWT was done for the reconstructed signal to highlight fault features’time-frequency distribution information and extract fault features. The analysis results of simulated signals and test data showed that this method can effectively eliminate noise effects and clearly extract the fault signal’s characteristic frequency to realize the accurate recognition of rolling bearings’faults.
  • RAN Wenmin1,LI Zhengchuan2,LI Xiaozhen1,YI Bing3,ZHANG Xun1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 218-224.
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    In order to study vibration problems of a high-speed railway station structure under train load excitation,a frequency domain analysis model for vibration responses of the station structure was established. Taking Chongqing Shapingba integrated transportation hub as an engineering background,a vehicle-track coupled model,a finite element (FE) model for track-soil and a FE model for the station structure were established. The dynamic wheel-rail force was solved with the vehicle-track model,and the vibration amplitude response at the column bottom of the station was solved using the track-soil FE model with the dynamic wheel-rail force exerted on the track line. The latter was taken as the external load to be applied on the station structure FE model,and finally the vibration response of the station structure was solved. Then,the influence of fastener stiffness on the station’s vibration was discussed. The results showed that the vibration response of the office at the first floor of the station is the largest when a train passes through the station; when designing the station,a lot of attentions should be paid to the office’s vibration problem; the main frequency range of the station vibration is within 10—60 Hz,its peak frequency is concentrated at 40 Hz; when taking vibration reduction measures,the station vibration at 40 Hz should be concerned; increase in fastener stiffness can effectively reduce the station vibration response within the frequency range of 6.3—31.5 Hz,but the station vibration response within the frequency range of 40—80 Hz rises.
  • WANG Zuyao1,DING Hu2,CHEN Liqun2,3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 225-229.
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    Here,nonlinear dynamic behaviors of a magnetic levitation energy harvesting system attaching a linear oscillator were studied under multi-frequency excitation. The nonlinear dynamic equations of this electromagnetic-mechanical coupled model were approximately solved using the harmonic balance method and the arc-length extension method. In addition,the approximate analytical results were verified with a direct numerical simulation. The results showed that with increase in the mass ratio of this energy harvesting system,resonance peaks of its middle magnet’s average power amplitude-frequency response under multi-frequency excitation increase from two peaks to four ones,the resonance peaks’amplitudes decrease,but their bandwidths are wider; adjusting the system’s parametric damping ratio and coupling coefficient can optimize intensities and bandwidths of resonance peaks to enhance the vibration energy harvesting effect.

  • GUO Kaiqiang1, JIA Yanmin1, YU Gunglong1, WANG Jiawei2,ZHANG Guanhua2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 230-235.
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    Based on the basic theory of structural vibration,the theoretical calculation formula for natural frequencies of a simply supported beam with straight unequal pre-stressed reinforcements was deduced using the free vibration equation of beams. Taking a certain bridge as the engineering background,modal tests for two pre-stressed concrete hollow slab beams of this bridge were conducted,and modal analyses were done for these two tested beams with the finite element (FE) software ANSYS. The results showed that measured values,FE analysis values and calculation values using the theoretical calculation formula agree well with each other; the deduced formula is reasonable and accurate to calculate the first two-order vibration frequencies of the simply supported beam with straight unequal pre-stressed reinforcements. Finally,the effects of pre-stress and eccentricity of pre-stressed reinforcement on natural frequencies of a simply supported beam with straight unequal pre-stressed reinforcements were analyzed using the theoretical calculation formula and the FE model.
  • ZHANG Yang,DENG Zhaoxiang,WEN Yiyun
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 236-240.
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    The correctness of the finite element method (FEM) to predict vehicle exhaust muffler’s performance was verified through comparing test results and simulation ones. The effects of the muffler’s substructure connection mode on its whole performance were discussed using FEM. The theoretical cause of these effects was explained from the view point of topology. A visual topology graph was proposed to intuitively reveal a muffler’s inner connection relations based on the graph theory and summarizing connection relations inside the muffler. The specific method for dividing the muffler substructures was gained according to different functional structures’different features indicated in the muffler’s topology graph. Finally,actual examples were used to verify the engineering applicability of the proposed muffler topology graph.


  • ZHANG Guiyong1,2,3,LU Huan1,WANG Haiying4,YU Dapeng1,SUN Tiezhi1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 241-248.
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    Aiming at problems of linear triangular element used by the traditional finite element method (FEM) having an over-hard stiffness and computed structure natural frequencies being larger,while the node-based smooth point interpolation method (NS-PIM) causing over-soft stiffness and making dynamic computation failure and computed natural frequencies too smaller,a node-based partly smoothed point interpolation method (NPS-PIM) was proposed here. This new method combined FEM and NS-PIM through partly strain smoothing operation to compute structural dynamic problems. It was shown that the proposed method overcomes NS-PIM’s deficiencies of time instability and solved natural frequencies too smaller; the same linear triangular element mesh was used to discretize a problem domain,the natural frequencies computed with the new method are more accurate than those with the traditional FEM; the new method is simple and easy to implement,and it has better prospects for engineering application.

  • ZHOU Yang1, HUANG Weiping2, YANG Bin3, PAN Chong3,SONG Zekun3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 249-255.
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    In order to study suppression effect of helical strakes on risers’VIV,model test method was used to conduct tests for VIV of 2-DOF risers including one bare riser and 3 risers with helical strakes of different pitches under different Reynolds numbers in a water channel. VIV differences among the bare riser and 3 risers with helical strakes were analyzed,and the effects of different helical pitches on risers’VIV were studied. Moreover,wake flows of these 4 risers during their VIV were observed with the tracer method. The results showed that helical strakes can disturb risers wake flows’vortex discharge to effectively suppress risers vibration responses in their transverse flow direction; compared to the bare riser,vibration responses in transverse flow direction of risers with helical strakes can be reduced by 70 percent,but their in-line vibration responses increase; the helical strake with a 9D pitch has the best suppressing effect on risers’VIV; Strouhal number of the bare riser is larger than those of risers with helical strakes under different Reynolds numbers.

     
  • CAO Jianhua 1,2, LIU Yongshou 1, LIU Wei 1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 256-260.
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    In-plane vibrations of fluid-conveying curved pipes were investigated by using the wavelet-based finite element (FE) method as a new attempt of wavelet in numerical calculation. In order to solve the high order differential equation of fluid-conveying curved pipes’in-plane vibration,the interval spline wavelet function was taken as the interpolation one of the displacement field. The curved pipe element with interval spline wavelet of scale 4 and order 6 was established. The wavelet-based curved pipe element mass matrix,stiffness matrix and damping matrix were derived. Then,the dynamic equations for in-plane vibration of fluid-conveying curved pipes were derived. In numerical examples,natural frequencies of fluid-conveying straight pipe and curves one were computed with the proposed method under several typical boundary conditions. The numerical results agreed well with those obtained using Galerkin method and the traditional finite element one,and the former costed less time. The study showed that the new type wavelet-based curved pipe element has a certain advantage in solving in-plane linear vibration problems of curved pipes; after further studying,it can be extended to analyze nonlinear dynamic problems of fluid-conveying curved pipes.
  • DU Wenzheng, MA Baozhu, CAO Dazhi, FU Guanglei
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 261-269.
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    To predict fatigue life of steel wire ropes under tensile load,the finite element model of a 6×36WS steel wire rope was established and its stress distribution under axial tensile load was simulated. The tensile fatigue test for the steel wire having the maximum stress was conducted to obtain its load-life curve. Then,the tensile fatigue life of the steel wire rope was simulated and its tensile fatigue test was conducted to verify the simulated result. The fatigue simulation result of the wire rope showed that under the axial tensile load,the maximum stress is located at the contact area of adjacent two strands where the fatigue life is the shortest; the fatigue life simulation result of the wire rope agrees well with that of its fatigue test,the load-life curve fitted with simulation data provides a basis for predicting fatigue life of steel wire ropes.
  • LI Kebin1, LI Xiaojie1,2, YAN Honghao1, WANG Xiaohong1, YANG Chenchen1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 270-276.
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    External environment variation makes shock wave propagation of air explosion produce obvious changes. In order to analyze the influence of degree of vacuum on near-field characteristics of air explosion,the finite element model of a free-field air explosion was established. Based on Sachs scaling law,introducing the characteristic scaled distance Z,the variation laws of explosion near-field characteristic parameters under various vacuum degrees were analyzed. Results indicated that the piecewise function taking Hopkinson scaled distance and the characteristic scaled distance Z as variables can express the explosion peak pressure Δpm within the full range of different degrees of vacuum; the variation of specific impulse i and positive pressure action time t+ is non-monotonic and closely related to sparse wave tail discontinuity surface of detonation product; time history curves of detonation product’s interface and shock wave front under different degrees of vacuum are overlapped,respectively in a dimensionless coordinate system,and the ultimate expansion volume is linearly related to critical distance Rs.


  • WU Wenfeng1, CHEN Xiaohu2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(17): 277-282.
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    Aiming at traditional mechanical vibration signals de-noising method’s limitation,considering partial differential equations’principle and application in image de-noising,a strong noise signal filtering algorithm based on wavelet transform module and modified Perona-Malik model was proposed. Firstly,the correlation between the wavelet threshold de-noising and Perona-Malik nonlinear anisotropic diffusion filtering model was studied. Secondly,wavelet transform module was used to substitute gradient module and construct an improved diffusion coefficient. The modified Perona-Malik model was derived based on wavelet transform module. The test results showed that compared with the traditional de-noising method and the basic Perona-Malik model,the modified Perona-Malik model can not only realize mechanical vibration signals’effective de-noising under strong noise background,but also keep signals’detail features with little signal distortion; it has a strong anti-noise capacity,the new algorithm makes the average SNR increase by about 3 dB.