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  • LIU Zhihao1,GAO Qinhe1,LIU Zhun1, WANG Xu1
    JOURNAL OF VIBRATION AND SHOCK.
    Abstract (299) PDF (21082)   Knowledge map   Save
    The experimental modal analysis, dynamic modeling and structural parameter identification were employed to research the inplane vibration modes of heavyloaded radial tires with larger flat ratio. The coupled characteristics of flexible tread, distributed sidewall element and rim were investigated by means of the experimental modal analysis. Taking the bending and inflation features of the flexible tread and the inertial force and sectional spring of the sidewall into consideration, the coupled kinematics of flexible tread, distributed sidewall element and rim was modeled. The inplane coupled analytical modal frequency was derived. The structural parameters identification was implemented and the higher order modal frequenies were predicted with the analytic method. The results show that: the flexible tread vibrates in the same/opposite direction with the distributed sidewall within 0-180 Hz and 180-300 Hz respectively ; the modal analysis and kinetics modeling in consideration of the coupled features of flexible tread, distributed sidewall element and rim can accurately characterize the inplane vibration features of heavy loaded tires within the frequency band of 300 Hz. 
  • TAO Ran1,2,XU Youcai2,HE Jie2,3,LU Yunbo2,3,QIAO Wangzhi2,3,YANG Chunyu2,3,ZHANG Junnan2,3,LI Jun2,WANG Hua1
    JOURNAL OF VIBRATION AND SHOCK.
    Abstract (452) PDF (12264)   Knowledge map   Save
    Aiming at the phenomenon of mode mixing in the extraction of fault information from the vibration signal of a high speed elevator rolling guide shoe,by the method of singular value decomposition (SVD) optimizing local mean decomposition (LMD), a feature extraction method based on self-adaptive sharpening wavelet decomposition (SSWD) optimizing LMD was proposed.First of all, the low pass filter, high pass filter, wavelet basis function and scale function were constructed.The original signal was decomposed into a high-frequency detailed feature signal and a low-frequency approximate signal by the multi-resolution filtering characteristics of wavelet decomposition (WD).Then, signal enhancement was done on the high frequency detailed feature components, and the enhanced high frequency detailed characteristic signal and the low frequency approximate signal were reconstructed.Finally, the LMD method was used to extract the fault features’ PF component of the rolling guide shoe from the reconstructed signals.The instantaneous Teager energy waveform of the PF component was obtained for comparative analysis.Through the actual working condition signal processing and analysing, the experimental results show that, compared with the SVD optimizing LMD method, the method completely extracts the fault characteristic components of the vibration signal of the rolling guide shoe, and avoids the phenomenon of modal confusion.
  • ZHONG Ming-shou1, LONG Yuan1, LIU Ying1, LU Liang2, LIU Jian-feng1, JI Chong1
    JOURNAL OF VIBRATION AND SHOCK.
    Abstract (304) PDF (10241)   Knowledge map   Save
    The collapse vibration performance laws of city viaduct to metro tunnel were obtained by using ANSYS/LS-DYNA software. The calculation model of collapse bridge impact to the underground tunnel of the city was established. Dynamic response of metro tunnel including three-direction vibration velocity and stress process of typical units was also obtained by comparison different conditions. The results show that as a main form of composite protective structure consists of Steel Plate-Rubber Tires system can make maximum of metro tunnel vibration velocity, compressive stress and tensile stress were decreased by 98.7%、95.6% and 94.4% compared with the absence of protective measures. It has shown excellent agreement between measured data and simulation results. Metro tunnel borne vibration speed is lower than the administration proposed safety threshold requirement and the design of comprehensive protection system achieved the expected result.
  • YU Yuanlin1 2, YANG Yi1, LIU Fujun3, SHI Biqing1, XIE Zhuangning1
    JOURNAL OF VIBRATION AND SHOCK.
    Abstract (365) PDF (9894)   Knowledge map   Save
    Here, 528 m high Nanning Wuxiang ASEAN Tower was taken as an engineering example, a new turbulent inflow generator named the narrowband synthetic random flow generator (NSRFG) was used to do the large eddy simulation (LES) for its wind-induced vibration response.Its base loads and displacement responses were calculated.The numerical wind tunnel’s simulation results were compared with those of the HFFB wind tunnel tests, and the effectiveness and correctness of NSRFG were verified.The results showed that the base bending moment power spectra simulation results in downwind and crosswind directions agree well with those of the wind tunnel tests, but the simulation results in torsional direction have a certain gap compared with the wind tunnel test ones; for the tower’s wind-induced vibration responses, the numerical simulation results in downwind direction agree well with the wind tunnel test ones, but the simulation results in crosswind and torsional directions are a little smaller; in across-wind direction, the predicted value for the vortex shedding frequency of the tower model with NSRFG was close to the wind tunnel test one.The study results provided a valuable reference for structural design.

  • 论文
    CHEN Haiwei ZHANG Qiuju SU Gaofeng
    . 2009, 28(4): 188-193.
    Abstract (3200) PDF (9721)   Knowledge map   Save
    This paper details pendulum characteristic linked with a vertical automatic washing machine. At first, a non-linear mode provided in [2] is linearized at its static equilibrium position and ingredients of its Jacobian matrix are analyzed. Second, the pendulum mode born with the machine is obtained by an eigensolution, and factors contribute to this mode are discussed. Third, relationships between the pendulum mode and a damp coefficient in the suspenders are found based on simulation results and pendulum characteristics are analyzed. The existence of the critical damp coefficient is discussed based on energy, factors affect it are then considered. Fourth, the bisection method is employed to determine the critical damp coefficient in a particular washing machine; relationships between the damp coefficient and radius of unbalance under different rotation speed are then fitted by several second order polynomials. The existence of the critical damp coefficient is supported through experiment and effect of the hydraulic balancer is finally discussed.
  • Guo Xuewei,Shen Yongjun,Yang Shaopu
    JOURNAL OF VIBRATION AND SHOCK.
    Abstract (324) PDF (7267)   Knowledge map   Save
    In this paper a new method of fault feature extraction based on sample entropy and fractional Fourier transform is presented. The core of this new method is to map the original data with poor separability into the appropriate fractional space firstly. Then the sample entropies of the transformed data after fractional Fourier transformation with appropriate order are computed and compared, so that fault feature extraction is fulfilled. The results show this new method could enhance the separability of different failure modes, and discriminate the normal, inner ring fault, outer ring fault and roller fault signals distinctly.
  • ZHAO Jiangang1, NING Jing1,2, NING Yunzhi1, CHEN Chunjun1, LI Yanping1
    JOURNAL OF VIBRATION AND SHOCK.
    Abstract (315) PDF (6356)   Knowledge map   Save
    A large number of signals collected by mechanical equipment monitoring system are usually nonlinear signals with multiple natural oscillation modes, so the single-scale feature extraction can’t characterize these nonlinear signals. For high dimensional feature matrix, its main lower dimensional features need to be further extracted. Here, to solve these two problems, a nonlinear feature extraction method combining multiscale permutation entropy and linear local tangent space alignment (MPE-LLTSA) was proposed. Firstly, signals were calculated using MPE to obtain multi-scale features with high dimensions. Then, LLTSA was used to excavate the embedded intrinsic structure, and realize low dimensional feature extraction. Finally, least squares support vector machine (LSSVM) was introduced to train and recognize low dimensional features. The test results showed that the proposed method has application potential in fields of mechanical pattern classification and fault recognition.
  • WANG Cheng1, WAN Bowen2, CHEN Yanyan3, MAO Feihong1, GUO Jing1, CHEN Juan1
    JOURNAL OF VIBRATION AND SHOCK.
    Abstract (443) PDF (5148)   Knowledge map   Save
    开展弧齿锥齿轮的试验研究可为理论设计、制造和装配等提供基础数据,提高弧齿锥齿轮的啮合质量和使用性能。以弧齿锥齿轮为研究对象,采用功率封闭试验系统,在准静态条件下开展试验研究。对不同转速和扭矩工况的传递误差和齿根应力开展测试,并从时域和频域角度进行了对比分析。结果表明:弧齿锥齿轮的传递误差呈正弦或余弦形式波动,并以转频对应幅值为主;随着扭矩的增加,弧齿锥齿轮传递误差峰峰值呈现递增的趋势,且传递误差转频对应幅值近似呈线性比例增加;转速对传递误差峰峰值影响较小,但对传递误差转频对应幅值影响较大。随着扭矩的增加,齿根应力峰峰值呈线性比例递增;转速对齿根应力峰峰值的影响较小;从小端到大端,齿根应力的变化很大且呈现增大的趋势;齿轮啮合过程中,轮齿进入啮合时,齿根应力为拉伸方向且应力逐渐增加达到峰值,随后轮齿逐渐退出啮合,齿根应力逐渐减小直至压缩方向并达到最小值;从频域角度齿根应力以转频及其倍频为主。
  • 论文
    LiLin Zhang Yongxiang Ming Tingtao
    . 2009, 28(4): 145-148.
    Abstract (1583) PDF (4696)   Knowledge map   Save
    Three different conditions of a gear, normal condition, crack in root of tooth, broken-tooth, are diagnosed by calculating the correlation dimension in the fractal theory. In order to weaken the effect of the noise on the precision of calculating , a new approach to filter based on EMD is put forward to pre-conduct the signal sampled. Through experiment with a gear box, this method is proved to be feasible and valid.
  • DOU Peng1,WANG Zhidong1,LING Hongjie2,XU Xiaosen2
    JOURNAL OF VIBRATION AND SHOCK.
    Abstract (405) PDF (4526)   Knowledge map   Save
    Based on the two-way fluid structure coupling theory, the numerical model of tuned liquid damper (TLD) and multi-layer multi-modal platform structure was established in this paper. The effects of TLD damping frequency and installation height on the first two resonant modes of multi-layer structure were systematically studied. The damping force has been quantified by numerical method. Combined with the phase delay relationship of sloshing wave and platform motion, the damping characteristics of TLD on multi-layer multi-modal platform structure were analyzed. The results show that the control effect of different installation positions of TLD is related to the maximum vibration mode of the corresponding mode of the structure. The damping frequency band of TLD can be widened by the frequency doubling excitation generated in the sloshing process. In addition, keeping the mass ratio of 2% unchanged, the multi-TLD system has a more stable vibration reduction effect on the multi-layer structure without local negative excitation. The average vibration reduction ratio at the two resonance points is better than that of other schemes.
  • LUO Yingqin, LOU Jingjun, ZHANG Yanbing
    JOURNAL OF VIBRATION AND SHOCK.
    Abstract (551) PDF (4400)   Knowledge map   Save
    A sound-absorbing structure of composite grid sandwich which is resistant to hydrostatic pressure is proposed. The grid spaces are filled with polyurethane matrix. The soft rubber coated iron ball is embedded in the matrix as a local resonance scatterer unit. The sound absorption performances of the structure under normal pressure and 3MPa static pressure are stable after compared by finite element method. The sound absorption mechanism was analyzed through discussing the relationship between sound absorption coefficient, average energy dissipation, the displacement and energy dissipation density fields. Finally, the genetic algorithm is used to optimize the broadband sound absorption performance of the structure. After optimization, the average sound absorption performance is increased by 150% and reaches 0.99 at a low frequency point where the thickness of the structure is less than λ/14, so that the small sized structure is realized to control the low frequency sound waves. It is expected to realize low-frequency broadband sound absorption design by adding more materials and structural parameters in the optimization model or filling different grid spaces with sound absorption microstructures that work at different low frequency points.
  • HAN Dongdong, LI Xin, WANG Wenhua
    JOURNAL OF VIBRATION AND SHOCK.
    Abstract (326) PDF (4071)   Knowledge map   Save
    The fully coupled aero-servo-hydro-elastic-linear foundation simulation tool is developed based on the recompiled FAST-SC-SSI, and the coupled linear spring is applied to simulate the soil-structure interactions (SSI). The reference offshore wind turbines is designed according to the NREL 5-MW baseline wind turbine and a monopile foundation. The parameters of tuned mass damper (TMD) in nacelle are designed based on the dynamic characteristics of monopile OWT with rigid and flexible boundaries. Reductions of the structural responses in the time and frequency domains are adopted to reveal the vibration control mechanisms of TMD and evaluate the influence of SSI on the TMD mitigation effects. Based on the performed investigations, it can be seen the significant influence of SSI on the reductions of structural responses, which should be emphasized in the design of TMDs for OWTs.
  • WANG Yanhua, LV Jing,WU Jing
    JOURNAL OF VIBRATION AND SHOCK.
    Abstract (323) PDF (3851)   Knowledge map   Save
    Recently the application of neural networks to the online model updating of hybrid testings is an important research direction.How to improve the adaptability, stability and anti-noise ability of online model updating algorithm of neural network is a key problem.An on-line model updating method for hybrid testings based on the forgetting factor and LMBP neural network was proposed, namely in each time step the historical experimental data of the test substructure were used to form a dynamic window sample with a forgetting factor.Then the LMBP neural network was trained with the sample set by the incremental training method, and the restoring force of the numerical element with the same constitutive model was predicted synchronously.The model updating hybrid testing on a 2-DOF nonlinear system was simulated and the RMSD of the predicted restoring force of numerical substructure was found to be 0.023 0 finally.The results show that the online model updating method of hybrid testings based on the forgetting factor and LMBP neural network has good adaptability, stability and anti-noise ability.
  • WANG Daoyong,XU Yanmin
    JOURNAL OF VIBRATION AND SHOCK.
    Abstract (193) PDF (3768)   Knowledge map   Save
    In this paper, the vibration control of vehicle with different shift time based on a semi-active hydraulic damping strut (HDS) is researched on how to reduce the shift time of vehicle in situ shift without increasing the shock and vibration of the vehicle. Firstly, the experimental and theoretical acceleration values of the active side of the engine mount and torque strut are compared and analyzed and the error is less than 20%, which verifies the effectiveness of the 13-DOFs vehicle dynamics model. Secondly, the semi-active HDS in the mounting system can effectively reduce the shock and vibration in the process of in situ shift quickly according to the dynamic response analysis and experimental test. Finally, the dynamic response characteristics of the vehicle with different shift time are analyzed by combining theory and test. The results showed that the shift shock and vibration caused by in-situ shift are mainly transmitted to the vehicle through the transmission mount and the torque strut. The transmission mount is insensitive to the increase of the damping of the mounting system, and the engine mount is insensitive to the vibration of the powertrain. The introduction of semi-active HDS in the powertrain mounting system can reduce the in-situ shift time and fuel consumption.
    Key words:in situ shift; shift time; shock and vibration; semi-active hydraulic damping strut; vibration control
  • Weimin Wang Sanqun Ren Lifang Chen Shan Huang
    JOURNAL OF VIBRATION AND SHOCK.
    Abstract (322) PDF (3727)   Knowledge map   Save
    Accurate measurement of blade vibration with the use of fewer sensors and more compact installation space is indispensable for engineering applications. Based on the measurement method of BTT, the combination of the nonlinear least squares fitting and GARIV method is proposed and experimentally studied to identify the synchronous vibration parameters of blade. A high-speed straight blade test bench was established (the maximum speed is 45000rpm, and the blade tip velocity is 322.8m/s). In the experimental study, the parameter identification of synchronous vibration of blade is completed and the Campbell diagram of blade vibration is accurately plotted under the excitation of six magnets. Meanwhile, the experimental study and analysis on the harmonic vibration of blade with different numbers of excitation. The deviation of the dynamic frequency of blade between experimental result and simulation result is less than 6%. This method can provide a technical approach for blade fault early warming and non-contact measurement of dynamic stress.

  • SHEN Chao1,2, BO Jingshan1,2, ZHANG Xuedong3, ZHANG Jianyi2, LIANG Jianhui3, QI Wenhao1
    JOURNAL OF VIBRATION AND SHOCK.
    Abstract (206) PDF (3713)   Knowledge map   Save
    Under suitable conditions, strong earthquake can cause surface rupture and damage to projects.Avoiding a surface rupture zone caused by seismogenic fault is one of important contents of project site selection.Here, based on the geotechnical centrifugal simulation technology, the process of reverse fault dislocation was successfully simulated in 100g centrifugal field, and surface deformation evolution characteristics of 40 m thick dry sand and wet sand sites during bedrock having different dislocations were obtained.According to test results, the surface deformation process was divided into 4 stages including whole uplift stage, uplift deformation one, scarp translation one and deformation mitigation lag one.Finally, the recommended value of ground surface rupture avoidance distance for strong earthquakes was given.It was shown that the test study and related results here have important theoretical and practical significance for understanding and studying the deformation of soil body caused by dislocation of hidden reverse fault and determining the avoidance distance of surface rupture of seismogenic fault.
  • LIU Mingyang, YANG Jin, ZHENG Wei, FAN Endong
    JOURNAL OF VIBRATION AND SHOCK.
    Abstract (183) PDF (3246)   Knowledge map   Save
    The water supply network has a large number of branch pipes. The fluid flow state changes under the action of the branch joint, which produces a fluid noise. This branch flow-induced noise couples with the leak sound signal through the pipe wall. Aiming at the leak location under the interference of branch flow-induced noise. The proposed C-EFastICA algorithm based on EFastICA, which expanded the cost function, constraint function, and iteration rules of the instantaneous linear EFastICA technology in the time domain to the complex-valued domain. Because the algorithm can adaptively select the nonlinear function g to establish the cost function and iterative learning rules according to the generalized Gaussian characteristics of the signal, it has a higher separation precision for signal decomposition. The experiments show that the relative error of the obtained leak source signal with C-EFastICA is less than 12%, which is lower than the traditional C-FastICA algorithm.
  • HUANG Peng, CHEN Sheng, HUANG Shunjie
    JOURNAL OF VIBRATION AND SHOCK.
    Abstract (222) PDF (3202)   Knowledge map   Save
    In wind disasters, the closed structures will become open structures after being destroyed, and the internal pressure of the structures will suddenly increase, which has greater damages to the structures. At present, the researches on wind-induced internal pressure mainly focus on the structure with opening on windward wall, but ignore the situation of leeward wall with opening. Firstly, the calculation method of wind-induced response of structure with opening on leeward wall was deduced theoretically. Then the natural frequencies of the internal pressure system and the internal pressure responses obtained from the field measurement and the theoretical calculation method were compared to verify the accuracy of the theoretical method. After that, a rational method about the opening area on the leeward walls was explored and established, which was demonstrated to have obvious effects on improving the load conditions of roofs under strong wind.

  • ZHANG Jiayan1,2, MENG Qingxi1, FENG Xugang1,WANG Bing1,HU Xuefeng1
    JOURNAL OF VIBRATION AND SHOCK.
    Abstract (205) PDF (3172)   Knowledge map   Save
    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.
  • Ren Yongsheng, Shi Yuyan, Zhang Yuhuan
    JOURNAL OF VIBRATION AND SHOCK.
    Abstract (196) PDF (3119)   Knowledge map   Save
    The nonlinear free vibration and stability of an internally damped rotating composite shaft were investigated. The shaft was assumed as an inextensional rotating beam with nonlinear curvature and inertia. The internal damping was described by the dissipative behavior of composite. Based on the constitutive relations and the strain-displacement relations of composite, the strain energy, virtual dissipative work and kinetic energy of the shaft were obtained. The equations of motion governing the nonlinear bending-bending vibration of the rotating composite shaft were derived using the extended Hamilton principle. The partial differential equations of motion were reduced into ordinary differential equations by the Galerkin’s method. In order to find the boundaries of stability, the corresponding linearized model of the composite shaft was used in eigenvalue analysis. The critical rotating speeds and instability thresholds of composite shaft were provided. The fourth-order Runge-Kutta method was used to integrate numerically the differential equations of motion. The displacement-time responses, phase plane curves and power spectra of the shaft were presented. The effects of the ply angle, ratio of length to outer radius and stacking sequence on the nonlinear bending vibration responses of the composite shaft were evaluated.
     
  • WANG Quan1,2,LIN Chaojian1,LI Zhimin3,LU Junwei1,LI Rui1,2
    JOURNAL OF VIBRATION AND SHOCK.
    Abstract (355) PDF (3040)   Knowledge map   Save
    In order to study the vibration and noise characteristics caused by the explosion inside a vessel under negative pressure, a set of 34.8 L vacuum-pumped explosive vessel devices was developed.A single industrial detonator No.8 was used as the explosion source in the experiments, and the vibration velocity and the sound pressure level of explosion noise were measured by a NuBox8016 blasting vibration tester and a SZ4A noise vibration tester respectively.The vibration signal was analyzed by the fast Fourier transform(FFT) and empirical mode decomposition(EMD) method.The results show that with the increase of vacuum degree, the peak vibration speed of the cylinder and the sound pressure level of explosion noise all show a downward trend.When the vacuum pressure in the cylinder is -99 kPa, the harmful effects of explosions are effectively attenuated.Compared with the normal pressure condition, the peak vibration speed is attenuated by 70%, and the maximum noise sound pressure level is reduced by 18.3%.According to the FFT and EMD results, the main vibration frequency of the cylinder increases with the increase of vacuum degree, and the number of IMF components with high contribution rate increases.The test and analysis results have guiding significance for exploring the explosion vibration and attenuating its noise signal under negative pressure, as well as for extending the engineering the application of vacuum explosions.
  • JIN Pengcheng, ZHOU Jianxing, QI Le, WANG Shengnan, ZHOU Hengyu, SONG Lirui
    JOURNAL OF VIBRATION AND SHOCK.
    Abstract (156) PDF (3031)   Knowledge map   Save
    In order to study the dynamic performance optimization method of multistage fixed-axle gear train,a parametric dynamics model including gear design parameters (number of teeth,modulus,tooth width) and system layout parameters (gear installation position,interstage phase Angle) was established by using the generalized finite element method. Newmark-β time domain integral method was used to solve the dynamic equation at rated speed,and the influence of each parameter on the dynamic characteristics of the system was analyzed. On this basis,the multistage fixed axis gear system dynamic optimization method is proposed,taking design and layout parameters as variables,reducer gear ratio,the diameter of axle width as constraint conditions,such as dynamic load amplitude and minimum on bearing load difference as the main target,multi-objective hybrid discrete optimization model is established, and obtain the optimal design variables based on bayesian algorithm programming model. The results show that the amplitude of the first stage meshing force of the optimized reducer is reduced by 18.9%,the amplitude of the second stage meshing force is reduced by 17.2%,and the load difference of bearings on both sides of shafting is reduced by 36%,40% and 45% respectively. The mass decrease by 8.7%,the volume of boundary box decrease by 27%,and the optimization effect is obvious.
  • GUO Linsheng1, WEN Yongpeng1, SHANG Huilin2, ZONG Zhixiang1, SUN Qian1
    JOURNAL OF VIBRATION AND SHOCK.
    Abstract (213) PDF (2938)   Knowledge map   Save
    In order to study relationship between vibration characteristics of urban rail elastic vehicle body and under-vehicle equipment, a rigid-flexible coupled multi-body dynamic model for the equivalent Euler beam vehicle body with under-vehicle equipment was established using the modal superposition method.Vibration responses of the vehicle body’s middle part and the upper one on the vehicle bogie were analyzed under various different operating conditions.The sensitivity of the first-order elastic modal frequency of the vehicle body to the elastic resonance velocity was discussed.Along the whole vehicle length, the coupled vibration relationship between the vehicle body and the under-vehicle equipment was analyzed.The variation of the whole vehicle’s vibration was analyzed to evaluate the stability of the vehicle at last.The results showed that elastic suspension of under-vehicle equipment can effectively suppress vibration of the entire vehicle body; from the view point of suppressing the entire vehicle body vibration, it is necessary to symmetrically install the equipment under the middle of the vehicle body, and choose different elastic suspension devices for under-vehicle equipment with different mass; the vehicle body’s elastic vibration is greatly affected by the resonance speed, vehicle operation under non-resonant speed can effectively avoid the overall vehicle elastic resonance and improve passengers’ comfort; the study results provide a reference for reducing elastic vibration of urban rail vehicles, improving passengers’ comfort, reasonably locating under-vehicle equipment and appropriately choosing its elastic suspension devise.
  • 论文
    RONG Bao;RUI Xiao-ting;Wang Guo-ping;YANG Fu-feng
    . 2011, 30(7): 178-187.
    Abstract (1907) PDF (2926)   Knowledge map   Save
    Multibody system dynamics is an important branch in the field of the modern mechanics. It provides a
    strong tool for dynamic performance estimation and optimizing design of many mechanical systems in a lot of important
    engineering fields, such as, weapon, aeronautics, astronautics, vehicle, robot, precision machinery, and so on. The study
    on dynamic modeling, design and control of complex multibody systems is the urgent demand of modern engineering
    problems. The studies on the dynamic modeling methods, computational strategies, control design, software
    exploitations, and experiments of multibody systems in recently years are reviewed. The future directions of this field are
    indicated.
  • GUO Jian-ying1 BAI Yan-yan 2
    JOURNAL OF VIBRATION AND SHOCK.
    Abstract (190) PDF (2882)   Knowledge map   Save
    Non-homogeneous, shear deformation and rotary inertia effects must be taken into account in vibration analysis of laminated metal thick-walled short tubes. Based on Timoshenko’s beam theory, the analytical expressions of the frequency and modal function of laminated metal tubes are deduced for four boundary conditions: hinged-hinged, clamped-clamped, free-free and clamped-free. The natural frequencies of copper-steel laminated tubes are solved and mode shapes are mapped by used of computer algebra system MAPLE for these four cases. The natural frequencies of three copper-steel laminated tubes with different length are also measured by method of hammer tests combined with finite element modal analysis. The theoretical solutions of the first three natural frequencies of copper-steel tubes are compared with the measured values, the maximum error of -4.56%, compared with the finite element, the maximum error of -0.76%. The frequency influence coefficients of shear deformation and rotary inertia on the laminated metal thick-walled short tubes are solved. The variations of the frequency influence coefficients and modal shapes with the boundary condition, frequency order, the aspect ratio, the non-homogeneous material parameter of laminated metal tubes are also investigated.
  • CUI Guangyao1,JI Lei1,WANG Mingnian2,3,ZHU Chang’an4
    JOURNAL OF VIBRATION AND SHOCK.
    Abstract (316) PDF (2751)   Knowledge map   Save
    In order to study shock absorber technology with rigid-flexible combination for tunnel opening section in high intensity seismic areas, taking the entrance section of Bai-yunding tunnel as a background, large-scale shaking table model tests were conducted to study peak acceleration of ground motion, longitudinal strain, contact stress and structural internal forces through analysing test data. The test results showed that only taking structural strengthening measures, the growth percentage of structure safety factor minimum value of the whole tunnel opening section is between 30%—65%; only setting a shock absorption gap, that is between 40%—55%; the shock absorption gap has an obvious action to reduce forced displacements, and its shock absorption effect is obvious; taking the shock absorber technology with rigid-flexible combination, the growth percentage of structure safety factor minimum value of the whole tunnel opening section is between 85%—145% and its action is remarkable to resist earthquake motion and reduce forced displacements, the shock absorption effect is the best. The study results provided a reference for improving the aseismic performance of transportation tunnels in high intensity seismic areas.
  • 论文
    LIU Xiang-jian CHEN Ren-wen
    . 2012, 31(16): 169-176.
    Abstract (1210) PDF (2717)   Knowledge map   Save
    Abstract: With the development of wireless technology and micro-electro-mechanical technology, electrochemical batteries as power sources have many flaws. On the contrary, piezoelectric vibration energy harvesters receive more attention because of their advantages of simple structure, no pollution and easily microminiaturizing. Beginning with the piezoelectric materials and their piezoelectricity, the piezoelectric vibration energy harvesters are reviewed based on the structure design and energy harvesting circuit design in this paper. Based on the directivity and band of the piezoelectric vibration energy harvesters, the improvements of the structure design are introduced in detail. Based on the energy harvesting efficiency of the piezoelectric vibration energy harvesters, the improvements of the energy harvesting circuit design are also introduced. Finally, the development perspective of the piezoelectric vibration energy harvesters is summarized. This paper will be helpful for the researchers who are engaged in the studying on the piezoelectric vibration energy harvesting.
  • LENG Wuming1,2, ZHAI Bin1, XU Fang1,2, ZHANG Qishu1, AI Xi1, HAN Xu1
    JOURNAL OF VIBRATION AND SHOCK.
    Abstract (187) PDF (2644)   Knowledge map   Save
    The cumulative plastic deformation of subgrade soils under long-term cyclic dynamic loads is discrete. Firstly, a series of large-scale dynamic triaxial tests of a coarse-grained soil filling were conducted to investigate the development trend and variation law of cumulative plastic strain with confining pressure, dynamic stress and water content. The results show that the cumulative plastic strain and its stable value increase with the increase of dynamic stress and decrease with the increase of confining pressure, indicating that the increase of confining pressure can effectively inhibit the cumulative plastic deformation of the soil. The dynamic stability of the soil increases with the decrease of water content. Secondly, based on the semi-logarithmic prediction model, the relevance theory of grey systems is adopted to explore the correlation between the model parameters and water content and dynamic-static stress ratio, and a normality test is performed to demonstrate that the model parameter controlling the growth rate of the cumulative plastic strain of the coarse-grained soil obeys a normal distribution. Finally, based on the probability failure theory, a probabilistic model for predicting the cumulative plastic strain of coarse-grained soil fillings is proposed, which can predict the cumulative plastic strain development range of coarse-grained soil fillings under cyclic dynamic loadings.
     
  • 论文
    Piao Ming-wei Fang Ji Zhao Qian-xu Zhao Wen-zhong
    . 2009, 28(3): 1-5.
    In order to analysis the influencing extent of structural vibration effects on fatigue life, a methodology of vibration fatigue analysis was presented based on rigid-flexible coupling simulation. With the Interface Transaction Technical Strategy (ITTS) for flex-body, the model of rigid-flexible coupling system is established, in which the flex-body can produce the elastic vibration characterized by the relevant modal vibrations under the dynamical constraint interactions. By the Component Modal Synthesis (CMS) approach of stress recovery, the following analyses are carried out to determine the fatigue quality and the influencing extent of vibration: the correlation between dynamical stress and modal vibration, and the stress range histograms by which the amplitude and number of cycle stress on critcal points are contrasted stastically among the multi-condition. For the vertical vibration problem of container flatcat, for instance, vertical acceleration on high side, it is sured that under the dynamical interaction of the wedge’s stick-slip friction, the flatcar produces the elastic vibration characterized by the 2nd vertical bending modal, which can be validated by both modal mass and attached mass models of flatcar. According to the modal correlation analysis and the statistical contrast of stress range histogram for the cycle stress on crotical points, the vertical and lateral constraint forces of container feets are one of the main causes of the large amplitude of cycle stress on critcal points, and the influencing extent of structural vibration on fatigue life is up to (20-25)%.
  • 论文
    MA Cong-Gan;ZUO Shu-Guang;TAN Qin-Wen;GAO Li-Hua;SUN Qing;MENG Shu
    . 2013, 32(12): 131-134.
    Abstract (810) PDF (2599)   Knowledge map   Save
    To solve the torsional vibration problem of permanent magnet synchronous motor (PMSM) which causes the body structure vibration and noise in electric vehicle, firstly, non-linear dynamical model of torsional vibration of PMSM was established with the lumped parameter method and the electromagnetic Torque of PMSM considering non-sinusoidal magnetic field distribution of permanent magnet, slotting and harmonic currents was obtained by an analytical method. Stiffness and damping parameters were obtained as well. It was indicated that electromagnetic torque ripple is the main reason of the torsional vibration of PMSM. Then, the non-linear differential equations were solved by means of the solved State variable technique. Finally, the model was tested and verified by the experimental results.