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. 

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.

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.

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.

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.

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。

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.

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

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.

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.

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.

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.

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.

简单的摩擦振子蕴藏着复杂的粘滑运动。由于摩擦的非线性非光滑特征，使得摩擦振子的理论分析相当困难，粘滑运动的数值仿真耗费大量时间。首先分析了干摩擦振子的亚谐双stop粘滑运动。进而给出了激励频率为固有频率三分之一时，干摩擦振子的双stop粘滑运动的精确解。并给出了此粘滑运动的存在的范围。最后用数值仿真验证了理论解。

It’s reviewed that the research progresses of road roughness in the field of automobile engineering and transportation engineering in recent years. Based on the difference of viewport of investigation, three aspects are discussed. First of all is the research of basic theory including the definition of road roughness and the mathematical model of road roughness in power spectrum, the second is the analysis of experiments which include the development of instruments of measurement and the research progresses of test and simulation in road roughness, once more is the application of road roughness in engineering of automobile engineering and transportation engineering. The principle, characteristic and application in engineering of many kinds of road roughness in the field of automobile engineering and transportation engineering are discussed synthetically. In addition, the roughness of Chinese representative road are mentioned which is used to study and design automobile in China. In the end, the prospect of road roughness in the field of automobile engineering and transportation engineering is summarized.

The proposed fast eigensystem realization algorithm (FERA) is an improvement of the ERA, which can improve the calculation efficiency and cut down the data storage. To avoid the singular value decomposition of Hankel matrix, the eigenvalue decomposition of a newly built symmetric matrix was adopted in the method. Asimulated fourstory frame structure was utilized for validating the accuracy and efficiency of the FERA method. The scaled El Centro earthquake was applied to the structure as an unknown excitation. Both FERA and ERA methods were used for extracting the modal parameters from the simulated displacements, velocities and accelerations, respectively. After comparing the modal analysis results with the analytical values, the conclusions show that the FERA can accurately identify modal parameters from any type of dynamic responses, and the computational speed can increase rapidly. In addition, the FERA was used for extracting modal parameters of an inservice pedestrian bridge through ambient test, and the results show that the proposed method can also work for the actual structure.

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.

 A method based on vibration signal is introduced for evaluating the spall size of rolling ball bearings, which utilizes the interval measurement of the double impulses generated by the spall and the rotor speed of the bearing mounted shaft. However, the measurement of the rotor speed is not convenient in some real working conditions. To address this issue, a method based on double impulses is proposed without a speed meter. The rotor-speed estimated by counting the number of impulses in a full rotating cycle of the shaft. By combined the rotor speed and average double-impulses intervals, the new method realizes the spall size estimation without the speed meter. It is appropriate for engineering applications. Experimental results indicate that the proposed method is valid.

In this paper, the main empirical formulas of collision force between ships and bridges are introduced respectively, which are adopted to calculate collision force for four Yangtze River standard bulk carriers. The non-linear finite element analyses are used to calculate the collision force with different DWT and velocities of ships as well. The curves between collision forces and DWT or velocities could be referenced in the bridge piers design. Comparing the collision force between ships and bridges with FEM and formulas, the formulas of JTG and TB are more suitable than IABSE and IABSE to calculate the collision force between bridge and V bow bulk carriers whose DWT are between 500t and 3000t.

Considering the influence of transverse shear deformation and large displacement, the basic non-linear dynamic equations of high pier under impulse loads are established. By supposing the displacement shape functions and applying the Galerkin method, the dynamical equations about times are gained. By using the four steps Runge-Kutta method, the dynamical equations are resolved, the critical loads and displacement response curves are obtained, and the influence of the vary kinds of loads and the geometry parameters of high pier on the critical loads are analyzed. The loads-displacement curves under triangle impulse loads are compared with under rectangle impulse loads. The displacement response curves under impulse loads with different peaks and the softness- critical loads curves under rectangle impulse loads are given. The influence of the different persist time of rectangle impulse loads on the critical loads is analyzed.

Aiming at the problem that the feature of incipient fault of rolling element bearing is difficult to be extracted under strong noise background, a fault diagnosis method based on MCKD and symmetrical differencing energy operator demodulation was proposed. For the filter size L and the period of interesting signal T play an important role in MCKD filtering, an adaptive MCKD filter which is based on cyclic correlation and LPSO was proposed, that can search for the best parameters automatically. The feature after filtering was outstanding, but some residual noise is still contained. To reduce the residual noise and get the demodulation spectrum, symmetrical differencing energy operator demodulation is used after filtering. The result of incipient fault diagnosis of rolling element bearing shows that this method is effective.

With the reduction of the production cost of various types of chopped fiber, fiber reinforced concrete has been developed on a large scale and its application fields are expanding. In order to ensure the service safety of fiber reinforced concrete in complex environment, this paper analyzes the concrete beam and carbon fiber (CF) with the fiber length of 6-8 mm and the volume content of 0.30% The low velocity impact tests of glass fiber (GF) and basalt fiber (BF) concrete beams were carried out to study the bending failure mechanism and fracture energy consumption of ordinary concrete beams and fiber reinforced concrete beams. The fracture process of each beam was recorded by high-speed camera, and the vertical displacement time history curve, acceleration time history curve and tension compression strain time history curve were extracted and analyzed. The impact force and inertia force of hammerhead were analyzed in detail, and the equivalent deformation force displacement curve was obtained, and the fracture energy consumption of each fiber reinforced concrete beam was calculated. The results show that the failure mode of each specimen is typical bending failure, and a vertical main crack is formed. The energy consumption of GFRC beam is the most, which is 88% higher than that of （plain concrete）PC beam. The energy consumption of CFRC beam and BFRC beam is 43% and 18% higher than that of PC beam, respectively. In this paper, the quantitative research results of mechanical properties and energy consumption of different types of fiber reinforced concrete flexural members under low velocity impact condition can provide reference for the engineering application of fiber reinforced concrete.