15 December 2018, Volume 37 Issue 24
    

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  • LIAO Gaojian1,CHEN Yong1,LIU Xi1,JIA Bin2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 1-6.
    Abstract ( 355 ) Download PDF ( 169 )   Knowledge map   Save
    In order to investigate the hypervelocity impact performance of honeycomb sandwich structures in spacecrafts, lightweight porous volcano rock projectiles were used to identify the micro-meteoroids, and hypervelocity impact tests were conducted to investigate the damage characteristics of honeycomb sandwich panels.The results show that the lightweight brittle volcano rock projectiles could be completely lunched by using a sabot with a silicon rubber pad.Following hypervelocity impact of volcano rock projectiles, the damage modes of honeycomb sandwich panels mainly took the forms of front surface perforation, honeycomb collapse, rear surface petalling and debonding, etc.The perforation diameter of the front surface increased with the diameter of the projectile, while the collapse area of the honeycomb and the failure area of rear surface were influenced not only by the impact energy and projectile diameter, but also by the impact position. 
  • WEI Jiuqi1,2,3,WANG Mingyang1,QIU Yanyu1,ZHAO Zhangyong1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 7-12.
    Abstract ( 289 ) Download PDF ( 78 )   Knowledge map   Save
    A total of 35 dynamic tests performed on the modified split Hopkinson pressure bar (SHPB) was used to investigate the effect of strain rate and density on the dynamic responses of calcareous sand and Fujian standard sand with the same particle size distribution.The results show that the two sorts of sand almost have no strain rate effect within the strain rate range conducted in this paper.Furthermore, the bearing capacity of quartz sand is much larger than the calcareous sand with the same relative density.When strains of specimens are the same, the bearing capacity increases with larger initial density.Under the effect of loading, the hydrostatic stress p and density ρ of sands have one to one  mapping relationship.The state equation p-(ρ/ρ0) of calcareous sand and the relationship between hydrostatic stress p and volumetric strain  εv were obtained.

  • HE Wenyu,HE Jian,REN Weixin
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 13-17.
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    Mode shape curvature change based damage localization methods possess the advantages of simple principle, intuitive results, and high efficiency.However, their application is limited by the requirement for high spatial resolution and reference mode shapes, and the central difference induced low anti-noise ability.This paper develops a new damage localization index (DLI) by using indirectly identified mode shapes.Firstly, the high spatial resolution mode shape in a damaged state was extracted from the moving vehicle response via the Hilbert transform.Then regional mode shape curvature (RMSC) was defined, and the mode shape information in an undamaged state was estimated by polynomial approximation.Finally, a DLI was formulated based on RMSC before and after damage to localized damage.Numerical studies were conducted to examine the effect of noise, and road roughness on the accuracy of the proposed DLI.

  • SHANG Huilin1,HU Lili1,WEN Yongpeng2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 18-23.
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    A class of micro mechanical resonator with electrostatic forces on both sides was considered whose complex dynamical behaviors were studied by the theories of bifurcations.It followed from the static bifurcation of the dynamical system that the increase of bias DC voltage would induce the static pull in of the microstructure.Basing on it, the obtained theoretical multiple periodic solutions were in agreement of the numerical results, which show that the safe jump phenomenon meant the multiple periodic solutions that caused by the losing stability of the two equilibriums.In addition, it was found that the increase of AC voltage would lead to the chaotic motion and pull-in instability.The investigation above may be helpful for preventing the complex dynamics, which can be applied to design the electrostatic micro resonators. 
  • YANG Renshu1,2,ZUO Jinjing1,YANG Guoliang1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 24-29.
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    The high speed schlieren experiment system and rock mass damage testing technology were used to discuss the propagation mechanism of slotted cartridge explosion wave and explosive gas, and the damage range of the rock mass was measured under doses of the slitting package.The experimental results show that the explosion shock wave and explosion gas of the slitting package are tracked and photographed.The separation study of the two effects was realized.And both maintain a high symmetrical state from the extended form.The blast wave propagates preferentially along the slit direction, and the formed "diversion" effect was preferentially applied to the blasthole wall.The generated initial damage area and the shock wave in other directions are caused by the expansion of the shock wave around the slit direction.The explosive gas first expands from the crack, and extends in a "one" shape mainly along the slit direction.The quasi-static pressure acts on the rock mass to promote the continuous development of cumulative damage zone, forms a “jet” effect along the slit direction, and promotes the continuous expansion of cracks.The increase of the dose has a great influence on the damage degree of the rock in the direction of the slit because the damage value of the rock mass in the direction of the slit is greater than in the direction of the vertical slit.
  • ZHENG Jiawei1,HE Zhongbo1,LI Dongwei1,RONG Ce1,YANG Zhaoshu2,XUE Guangming1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 30-37.
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    To meet the driving requirements of electro-hydraulic servo valves and solve the restriction between the size and the output displacement of the GMA, a bow-type structure was designed to amplify its output displacement.Through theoretical mechanics, material mechanics theory, the Lagrange’s dynamical equation and the finite element simulation method, the dynamic characteristics, displacement magnification of bow-type structure and the influence of its main structure size parameters on the displacement magnification were analyzed.The GMA with bow-type structure prototype was manufactured, the experimental system was established and the proposed model was verified by sweep and sinusoidal experiments.The results show that under sinusoidal excitation, the magnification of the bow-type structure fluctuated between 10.3 and 11.1, which was in agreement with the theoretical calculation.Under the sweep test, the maximum peak of GMA with bow-type structure was about 108 Hz, which was consistent with the theoretical calculation, and its bandwidth could reach 100 Hz, which could satisfy the servo valve output characteristic requirement.
  • HU Jinjun1,2, LI Qionglin1,2,L Jinghao1,2,XIE Lili1,2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 38-45.
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    Performing nonlinear time history analyses on structures of nuclear power plants with applicable input ground motions is important to improve the design of nuclear power plants.The selection of input ground motion based on conditional mean spectrum has been accepted by researchers because it can incorporate the behaviors of ground motions and the dynamic features of structures.Based on the probabilistic seismic hazard analysis, a condition mean spectrum was used as the target spectrum to select ground motions and 40 ground motion records have been selected in a database which is consisted by 2 480 records derived from 18 earthquakes.In addition, the procedures of computing the target spectrum based on the conditional mean spectrum was provided.An other group of ground motions with 40 records have also been selected by the epsilon method.The two groups of ground motions were input in an FEM model of vessel of nuclear power plants and the largest displacements at the top of vessel were achieved.The results show that the CMS method is an applicable selection method.
  • HAO Shu-ying 1,2 LI Hui-jie 1,2 ZHANG Chen-qing 1,2 ZHANG Qi-chang 3 FENG Jing-jing 1,2 LI Lei 3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 46-52.
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    To reveal the influence of stiffness nonlinearity on the stability and accuracy of double-sense micro-gyroscope sensitivity, firstly, the linear response of a double-sense equation was solved by using the complex exponential method.Secondly, the multi-scale method was used to analyze the nonlinear dynamic equation considering the influence of the Coriolis force on the sense output.An effective method to deal with the coupling term of high-dimensional nonlinear equations was proposed.The influence of the sense nonlinearity stiffness on the amplitude-frequency curve and the resonance frequency were studied.It is found that the sense nonlinearity stiffness causes the complex nonlinear behavior such as hardening, amplitude jumping, multiple solutions and resonance frequency shift, which leads to the instability of the micro-gyroscope sensitivity.The stability of the micro-gyroscope sensitivity and the unsteady bandwidth range are very sensitive to stiffness nonlinearity.When the stiffness nonlinearity reaches a certain value, its small growth will also seriously affect the stability of the micro-gyroscope sensitivity and increase the bandwidth instability range, which leads to linear system design failure.

  • WANG Feng1 ZHU Yanlin2 XU Xing1 CHEN Long1 ZHOU Zhiguang3 SUN Xiaoqiang1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 53-60.
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    In order to effectively analyze the nonlinear vibration characteristics of a high-speed cylindrical helical gear, effective suppression of tooth surface vibration, dynamic meshing stiffness of cylindrical helical gears with contact characteristics of tooth back was established through a loaded tooth contact model, and the coupling mechanism between meshing stiffness, meshing time and vibration displacement was obtained.The nonlinear vibration model of the high-speed cylindrical helical gear transmission system was established considering the excitations of tooth surface/back meshing stiffness and the corner impact force.The optimization of the surface modification of the double teeth surfaces was studied.The results of show that the meshing vibration acceleration of the helical gear with tooth back meshing stiffness is obviously larger than that without the stiffness, and the former performs more complex bifurcation characteristics.Compared to the standard tooth surface and the single surface modification, the cylindrical helical gear with double surfaces modification has the smallest meshing vibration acceleration, and it also increases the speed range for stable operation. 
  • BO Lin,TANG Tao,LIU Xiaofeng,WEI Daiping
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 61-65.
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    Aiming at the sensitivity of nonlinear Lamb wave to the detection of material properties, a nonlinear detection method based on the Duffing-Holmes system was proposed.First, the critical parameters of the Duffing-Holmes system were determined and the Duffing-Holmes system was adjusted to a critical state, then after being extended and filtered, the signal to be tested was adjusted and scaled as a disturbance input of the system.At last, a linear model between signal scaling coefficient and Lyapunov exponent was established.Lyapunov exponent of the reference signal and the linear model were used to achieve optimal estimation of the real amplitude in the presence of noise interference.Experimental results show that the method can effectively improve the noise immunity and nonlinear Lamb detection range of material nonlinear index.
  • ZHANG Yuzhi
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 66-71.
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    In order to control the higher mode effect on rocking self-centering tall piers, the contribution of higher mode should be assessed quantitatively.Based on comparison of current research methods, a mode decomposition method was adopted to calculate the contribution of higher mode for rocking self-centering tall piers.A new index that can be used to assess the contribution of higher mode during rocking was put forward based on the analysis of current various indexes.Using seven ground motion records for three different intensities as input, the higher mode contribution of a rocking self-centering tall railway bridge pier was studied with two springs rocking model built in OpenSEES.Results show that higher mode contribution increases with the ground motion intensity.Base shear is the most sensitive structural response to higher mode effect and the contribution of the second and third mode is 97% and 27% of the first mode.The contribution of the second mode to the base moment is 34% of the first mode.Pier top displacement is not sensitive to higher mode.The contribution of the second mode to pier top displacement is only 8% of the first mode.
  • WANG Pu,WANG Shuguo
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 72-79.
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    A numerical model was established, which can predict the wear distribution and development quantificationally.The influences of axle load, running speed and material hardness on rail wear distribution and development were studied systematically.This work solves the problems of lacking quantitative analysis in previous research.The major conclusions are as follows.① Influences of axle load: in the tangent section, with the axle load increasing, the rail wear are all distributed like saddle and the saddle feature becomes more obvious.The crest wear depth increases and the trough wear depth decreases.The wear loss tends to increase as a whole.In the curved section, the wear distribution is significantly different between the two rails.With the axle load increasing, the rail wear distribution characteristics remain almost the same, and the magnitude tends to increase.② Influences of speed: in the tangent section, with the vehicle speed increasing, the rail wear extends towards the inner side, and the wear depth increases over the distribution zone.In the curved section, with the speed increasing, the wear magnitude around the shoulder of outer rail decreases firstly and then increases, while the wear magnitude on the top of outer rail changes slightly.The wear magnitude of the inner rail decreases obviously.Compared with axle load, the influence of vehicle speed on wear is more significant.From the perspective of slowing down wear, priority should be given to developing heavy-axle load freight vehicle to expand the capacity of the heavy haul railway.Meanwhile, the speed of loaded vehicle should not be increased greatly.③ Influences of material hardness: Increasing the hardness will not influence the wear distribution zone and shape significantly, but can reduce the wear magnitude notably.However, excessive high hardness will accelerate fatigue damage and may not prolong the life-span of rail.
  • LIU Weiwei1,MAO Qibo1,2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 80-84.
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    The shunt loudspeaker is imposed to control the duct noise.The shunt circuit of the loudspeaker was optimized by using the pole placement method.First, the duct-loudspeaker coupling model as well as the shunt loudspeaker model was built up.Then the characteristic equation of the shunt loudspeaker control system pole was obtained.Considering dominant pole feature, the optimal parameters value of resistances and inductances were obtained.Meanwhile, the location of the shunt loudspeaker effect on the control performance was discussed in detail, and the optimal shunt loudspeaker locations for different target modes were presented.Finally, the duct noise control using shunt loudspeaker was experimentally verified.The numerial and experimental results show that the parameters of shunt loudspeaker circuit can be optimized by using the pole placement method.
  • GUO Dongming1,2, YAN Pengyang1, Fan Longfei1, YANG Jun1, XUE Lei1,LI Yanyan1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 85-91.
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    In order to investigate the dynamic response problem of the medium around the adhesive surface made by the adherence of early age sprayed concrete on rock, a split Hopkinson pressure bar (SHPB) of 75 mm in diameter were adopted to study the stress wave propagation rules and dynamic mechanical properties of the sprayed concrete-surrounding rock combined bodies at the age of 3 d, 7 d and 10 d.The experimental results show that the transmission coefficient is closely related to the impact velocity and the age of concrete.It will decrease as with impact velocity for the specimens of 3 d, 7 d and 10 d.The transmission coefficient increases with concrete age under the same experimental velocity.The damage degree will increases gradually as the growth of the strain rate.The failure pattern of the concrete changes from tearing strain damage to crushing damage, and the rock presents the tensile failure mode.The dynamic compressive strength and the dynamic strength increasing factor increase with the growth of strain rate.When the strain rate is beyond 80 s-1, it shows the plastic property for specimens at the age of 3 d and brittle property for specimens at the age of 7 d and 10 d.
  • SHEN Qingzhou,CHE Chidong
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 92-98.
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    The attenuation of structure-borne sound coupled with both bending and torsional wave at an L shaped junction was investigated by the wave approach.Several new non-dimensional coefficients were introduced to deduce the transmission and reflection at the semi-infinitive L shaped junction, which was extended to compute the vibration field in structure with finite length.Numerical computation was carried out to investigate energy transmission and reflection efficiencies.The results show that both total energy transmission efficiency and waveform transformation ratios increase with frequency.Furthermore, a simplified experiment was carried out on an L-shaped beam which validates that the vibration fields in finite structures may be computed with transmission and reflection coefficients in infinitive ones.The results from above study are useful to guide the acoustic design for ships.

  • JING Xiangyang1,YANG Lifu2,3,MA Gang3,ZHOU Wei3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 99-105.
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    Using the finite element mesh generation method, a method of modeling convex or concave polygonal particles was proposed.Particles with more realistic shapes were generated by the control of parameters, and simulations of complex shaped particles including concave polygons were realized.DEM simulations of shaking table model test for concrete faced rock-fill dam (CFRD) in irregularly shaped grain were presented in this work and the dynamic characteristic were revealed from perspective of micro mechanics.The study results indicated that the concrete face slides from the base during earthquake.As the peak acceleration increasing, the dip angles of sliding plane for the grains in the downstream of CFRD increase and the crest settlement and skeleton dilatation become more intense.The major principal direction of normal contact forces was closed to the vertical before earthquake while the angle shifts to the downstream after earthquake.The anisotropy of normal contact forces increases with peak acceleration.Under the same initial fabrics, the average friction mobilization for CFRD was unvaried and irrelevant to the acceleration input.
  • XIAO Huifang1,2,SUN Yunyun1,XU Jinwu1,SHAO Yimin3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 106-114.
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    The normal contact stiffness is an essential parameter for describing the interface characteristics and exhibits significant influence on both the static and dynamic behavior of the mechanical system.In this work, a general contact stiffness model was proposed to study the mixed lubricated contact for rough surface contact.The total interfacial contact stiffness was composed of the dry rough surface contact stiffness and the liquid lubricant contact stiffness.The Greenwood-Williamson model was used for surface topography description and the whole dry rough contact stiffness was obtained.The liquid film stiffness was derived based on the film resonance model and the spring model spring model.Effects of surface roughness, property of lubricant layer and property of contact solid on the normal contact stiffness were analyzed.Results show that the acoustic impedance is the main factor determining the liquid film stiffness and the liquid film stiffness decreases with acoustic impedance.The surface topography and elastic modulus are the main factor determining the solid contact stiffness.The proposed calculation model for normal contact stiffness of rough surface in mixed lubrication provides foundation for stiffness calculation, performance predication and optimization of mechanical structure.
  • MA Liying,LI Xiangdong,ZHOU Lanwei,ZHANG Gaofeng
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 115-122.
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    To study the influence of the liquid medium type on the hydrodynamic ram effect, the influence of water, diesel and aviation kerosene on the hydraulic ram effect was analyzed by ANSYS / LS-DYNA and verified through experiments.The results show that the fragment in the water consumption of energy accounted for about 40.28% of the total fragmentation of the total kinetic energy, followed by diesel, and aviation kerosene consumed minimal energy in the process of liquid-filled container impacted by the fragment with the speed of 1 000 m/s.The attenuation coefficient of the fragment velocity is about 1.29 times of that in the aviation kerosene.The difference of the drag coefficients in the three media is not obvious, which indicates that the liquid density is the main influencing factor of the law of the fragmentation in the liquid.The maximum deformation of the rear wall of the water-filled container is 1.22 times of that in the aviation kerosene container, indicating that hydrodynamic ram effect does more serious damage to the container filled with water.
  • XU Ying,NIU Li,ZU Hongguang
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 123-130.
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    Welded I-section steel members are widely used in engineering, and it is prone to fatigue damage at the web/flange junction under cyclic load.Due to the sudden damage and the heavy losses, it is necessary to detect the damage in time.Based on the study of stress wave propagation mechanism in steel beam, a broadband impact wave was generated by a hammer striking on the surface of a steel Ⅰ-beam, and the fiber interferometer was attached to the surface of steel beam to receive the stress wave signal.By analyzing the impact echo signal spectrum, the existence and location of the damage was determined.Numerical analysis and experimental results show that it is feasible to detect the fatigue damage at the flange/web junction of the steel Ⅰ-beam by the impact-optic method.
  • CHEN Lifang,CHEN Zhechao,WANG Weimin,QIN Yue,LI Zhaoju,YAN Ziwen
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 131-136.
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    As a new dynamic balancing technology, autobalancing can achieve online vibration suppression.An autobalancing control strategy based on APSO was proposed,which combined with BP neural network to achieve the autobalancing of the system by one startup and shutdown.In the process of startup and shutdown procedure, the algorithm takes the parameters of the balance block and the working speed as the neural network input.The residual vibration value of the system was used as the output.The residual vibration prediction value of the network was used as the objective function.This algorithm was used to optimize the parameters of the balance block when the objective function value reaches minimum.Simulation and experimental results shown that, the APSO-BP method can complete the balancing automatically in the steady and unsteady state.The experiment shows that, during the variable speed process, the amplitude of unbalance vibration assignment dropped  by about 75% in 14 seconds.
  • LU Chengzhuang1,LI Jingyuan1,ZHOU Bangyang1,FANG Xu1,LI Yi2,HE Ronghui2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 137-142.
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    The single austenite metallic wire was chosen to the metal rubber fabrication, combined with the materials characteristics, to improve the fatigue properties of metal rubber in vibration environment.The metal rubber fabricated by two different wire materials was investigated by the comparative analysis of the wire materials properties in fatigue vibration acceleration tests.The effects of the materials characteristics on fatigue properties of metal rubber were discussed.The results showed the dynamic average stiffness of metal rubber decreases with vibration time and its variation was affected by the inner wire material property and the contact state of spiral coils.The analysis of microstructure and phase reveals that the single austenite metallic wire material possessed excellent toughness.The loss of metal rubber stiffness and mass made by austenite metallic wire was minimum reduction.However, the wire with the deformation martensite and retained austenite was opposite.It is concluded that the single phase austenite metallic wire is necessary for the metal rubber to obtain higher fatigue properties of metal rubber.
  • YANG ZhiAn 1 FENG Hao 2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 143-147.
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    Taking a capacitance type electromagnetic actuator as the research object, the driver consists of a capacitor, dielectric plate and nonlinear spring.According to the Lagrange Maxwell equation, the nonlinear vibration equation of the system was established.Applying the method of multiple scales, the primary resonance of the system problems was analyzed and numerical calculation was carried out.The amplitude frequency curves of the system was obtained.The results show that the amplitude frequency response curve of the primary resonance of the system has no jumping phenomenon.This system is a weakly nonlinear system.With the increase of the damping coefficient and the distance between the two electrodes of a capacitor, the amplitude and the region of the primary resonance of the system decrease.With the increase of the excitation voltage and the length of a capacitor, the amplitude and the resonance region of the system increase.
  • YAN Jun1,LI Zeliang1,ZUO Gong1,LI Shengcai2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 148-157.
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    Through low cyclic horizontal loading tests on 12 welded closed stirrup concrete columns, the failure patterns, hysteresis curves, the skeleton curves were measured, and the ductility ratios, energy dissipation capacity, strength degradation ratio were analyzed as well.The results show that, with the increase of the shear span ratio, the ultimate bearing capacity of the specimen decreases.With the increase of the ratio of axial compression, the bearing capacity and ductility of the specimen increases.With the increase of the volume-stirrup ratios, the ultimate bearing capacity of the specimen increases, the ductility and energy dissipation capacity increases also.A series of drift limit for the four different seismic performance level are recommended based on the test results.
  • ZHU Jinbo1,ZHENG Shixiong1,TANG Yu2,GUO Junfeng1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 158-165.
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    The self-excited aerodynamic force of the streamlined box girder cross section is related to the amplitude nonlinearly.In order to predict the flutter critical wind speed accurately and then explore the post flutter state with the large amplitude vibration, self-excited aerodynamic forces varying with converted wind speeds and amplitudes were identificated based on the established numerical tunnel wind model.Then the corresponding nonlinear flutter derivatives were calculated.On the basis of the classical flutter theory, a finer complex modal eigenvalues solution method of two degrees of freedom, considering the factors of flutter amplitudes, was proposed.Based on this method, a program for searching the nonlinear flutter amplitude response was developed, and the amplitude characteristics after flutter were investigated.The results show that under the single frequency vibration of single degree of freedom, the proportion of aerodynamic nonlinear components increases with the amplitude of bridge section, especially the single twist.The flutter analysis method developed in this paper can accurately predict the flutter critical wind speed.After flutter, vibration amplitude will appear a step growth.When achieving a substantial value, the amplitude will be in the vibration state of increasing slowly.
  • ZHU Dapeng
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 166-171.
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    An acceleration response first passage failure probability estimation method for nonlinear package excited by random base excitation was presented in this paper.The random vibration excitation was presented in normal random variable space, an analytical method was used to obtain the first passage probability.The design point is essential information for the failure probability analysis.The model correction factor method (MCFM) was used to develop an approach to approximately obtain the design point, since the MCFM always provide upper bound to the reliability index, the parameters of idealized system were determined by minimizing its reliability index.The acceleration response first passage failure probability can be estimated by the first order reliability method.An example was presented in this paper to demonstrate the accuracy of the method.The method in paper is important for the vibration reliability analysis and design optimization of the package.
  • HU Wen1, WU Yang1, CHEN Shengzhao1, ZHANG Bangji1, ZHANG nong2, SHENG Qihao1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 172-180.
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    To balance the conflict of anti-roll performance and passing ability for off-road vehicle, a new suspension scheme (Dynamic Torsion-elimination Suspension, DTS) was proposed.The vehicle equipped-with a DTS can obtain larger anti-roll moment and better wheel ground adhesion.After the structure depiction, the dynamic model of DTS and a 14 degree-of-freedom vehicle dynamic model were established with MATLAB.The key parameter analysis and matching of DTS were then carried out through a novel method which is based on anti-roll and torsion-elimination performance requirements.The serpentine experiment, steering transient input and asynchronous-sine twist road input were adopted to evaluate the dynamic performance of the proposed DTS and the validity of applied parameters.Simulation results show that this novel suspension system is able to improve a vehicle’s anti-roll performance and passing ability without compromising its riding comfort.Besides, the understeering performance of vehicle is enhanced as well.
  • WANG Guilan1,ZHAO Hongshan1,GUO Shuangwei2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 181-188.
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    A gearbox is a premier part of the drive train in the wind turbine.Once the gearbox has fault, it will not only produce high maintenance cost but also result in longer power outages.Performing on-line condition monitoring and the early fault detection and isolability of the gearbox thus has important practical significance for the assessment of wind turbine health.However, the effectiveness of the on-line condition monitoring and the early fault warning mainly depends on the installation location and number of sensors in the gearbox.Therefore, it is necessary to study the sensor configure of the gearbox.To accurately reflect the operational status of the gearbox and detect and insulate the fault that may arise, a dynamic equation describing the gearbox behavior was built.The structural analysis method was applied to optimize the allocation of the gearbox sensor, achieve the optimization goals of maximum fault detection and isolation.
  • LU Qingzhen1,YANG Zhixun2,CHEN Jinlong3,XIONG Feiyu2,YAN Jun2,YUE Qianjin1,2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 189-194.
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    The fatigue problem of dynamic umbilicals induced by wave load and floater movement in deepwater was studied.The prediction method of the fatigue life was established by considering the influence of mean stress due to self-weight on fatigue damage of key component steel tube.Solution of non-linear local stress was presented under basic mechanical behaviors of helical wound structure with consideration of contact and friction between components of the umbilical.A case study of a dynamic umbilical for 1 500 meters depth in South China Sea was presented.The results show that the more accurate result of the fatigue life was calculated through Goodman correction and non-linear local stress.The fatigue life by considering local stress with no-slip assumption was conservative.An obviously longer fatigue life was obtained by considering local stress with full-slip assumption.

  • GUO Pan1,WEI Hongtao1,WU Wenhua2,XU Guangtao3,ZHAO Jun1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 195-200.
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    A time discontinuous Galerkin finite element method (DGFEM) is used to simulate the problem of laminated piezoelectric material subjected to the high-frequency impulsive load.At present, the traditional numerical method for solving the dynamic problem of piezoelectric solid subjected to high frequency impulsive load generally fails to properly capture discontinuities of waves in space and interface between two layers, and produces spurious numerical oscillations in the simulation of high modes and sharp gradients.In order to filter out the spurious oscillations, an artificial damping scheme, which based on the DGFEM, was implemented in the final finite element formula.Numerical results of one dimension and two dimension show that the developed DGFEM presents good abilities and provides much more accurate solutions for piezoelectric problem.It can capture the discontinuities effectively at the wave front and wave after and filter out the effects of spurious numerical oscillation induced by high-frequency impulsive load.
  • XIE Wei,JIANG Xinsheng,XU Jiannan,ZHOU Yi,WANG Dong
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 201-207.
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    The pressure-time curve of combustible gas explosion is an extremely important curve in the study of the explosion characteristics, which reflects the real pressure change during the combustible gas explosion.The fitting of the curve will help to study the key features of combustible gas explosion more meticulously and quantitatively.Based on the experiment of oil and gas explosion in a confined space, the pressure characteristic curve of explosion in the confined space was fitted by the Gaussian multi-peak method, and the correspondence relationship between the fitting curve and the explosion process was analyzed.The results show that: the Gaussian multi-peak fitting method can obtain a more accurate expression of overpressure function in confined space explosion.And the more the number of fitting peaks, the more accurate the fitting result, but the lower the fitting efficiency.And the fitting results reflect the trend of pressure fluctuation at the measuring point and the pulse superposition method can be used to simulate the overpressure process very close to the actual explosion.And using this simplified fitting model can quickly estimate the total impulse of the whole explosion.
  • WEN Juan, GAO Hongli
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 208-213.
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    As a critical issue of condition-based maintenance, accurate prognosis of systems can improve the safety, availability and efficiency as well as reducing the maintenance cost.There are two main parts in model-based prognosis methods: degradation modelling and state estimation.Recently, particle filter (PF) has been widely applied in this area.However, there is a particle degeneracy problem with using PF.A remaining useful life (RUL) prediction approach of bearings was introduced by combining a stochastic process model and unscented particle filter (UPF) in this paper.Specifically, the degradation process of bearings was described with the stochastic process model, and the health state and model parameters were updated with UPF.Real test data were involved to demonstrate the effectiveness of the proposed technique.Compared with PF, the proposed method shows its superiority in particle degeneracy problem reduction and bearing RUL prediction.
  • FU Yi1, YU Zhefeng1, CHEN Baoxing2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 214-219.
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    An innovative shock absorber based on the failure of composite tube was presented.The energy absorber is composed of a composite tube and a connecting cap at both ends, wherein the inner surface of one connecting cap is plane, and the inner surface of the other connecting cap is a curved surface.The tube was folded and pushed into itself cavityunder axially impact.There is no debris overflowing after the composites collapsing, and the debris filled in the inner of tube increases energy absorption.The impact energy was mainly absorbed by the fracture of fiber, delamination and friction between composite tube and the cylinder wall of the sleeve.The correspondingstatic and dynamic impact experiments had been conducted to explore the effect of curvature of the inner cap surface on energy absorption.The results show that this innovative energy absorber is applicable for light weight crash worthy structures in terms of decreasing the initial peak load and increasing specific energy absorption (SEA).

  • DU Lingyun1,2, KE Shitang1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 220-228.
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    As a kind of novel cylinder-conic section steel cooling tower, the distribution of aerodynamic force on internal surface of tower drum is obviously different from traditional hyperbolic concrete cooling towers because of its unique structure form.Under extreme weather conditions with strong wind along with rainstorm, the rainstorm will affect the aerodynamic force on internal surface directly and change the turbulent effect of fluctuating wind.However, traditional researches have only paid attention to shock effect on the structure surface from wind driven rain.In order to solve this problem, aiming at a domestic novel straight cylinder-straight section steel cooling tower (189 high) under construction, the wind-rain two-way coupling algorithm as the core, the wind field and rain drops are simulated respectively by using continuous and discrete phase model based on CFD numerical simulation.The influence laws of parameters under different scenarios of wind speed and rainfall intensity were studied.The action mechanism of wind speed streamline and turbulence intensity in wind field of rain drops moving speed and trajectory inside the tower drum were revealed.The most unfavorable conditions of different wind speed and rain intensity combination and its internal pressure coefficient distribution character were extracted.
  • LIU Yaling1, LIU Yucun2, GENG Shaobo1, WANG Wanyue1, XUE Jianying1, LIU Lan1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 229-236.
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    Using a twin-cell box girder and three-cell box girder cross-sections that are commonly used in engineering, 14 steel box girder testing models were constructed at a 1∶10 scale, according to the similarity theory.While changing the structural parameters, such as the height of the girder, the thickness of the girder roof, the spacing and thickness of the U rib, and the spacing and thickness of the diaphragm plate, destructive tests on the close-range explosion of steel box girders were carried out with a given quantity of explosives and explosion distance.The results show that: the overpressure value is related to the failure state of the roof of the steel box girder; the energy method can predict the plastic deformation value of the steel box girder roof structure and the extent of damage to it; and that the damage state and extent of damage is a comprehensive multi-parameter result of mutual influences.The thickness of the roof, the spacing and thickness of the U rib, and the spacing and thickness of the diaphragm plate can improve the antiknock ability of the steel box girder roof.The U rib constraint is particularly important, as the degree of damage to the roof of the steel box girder can be reduced by more than 80% by increasing it.
  • FU Peng1, YANG Weiping1, WU Yongbo2
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 237-243.
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    Based on the high efficiency and surface quality of ultrasonic machining characteristics, and combined with high effectively controlling and little pollution features of fixed abrasive polishing, this work is to explore the process mechanism of the ultrasonic elliptic vibration assisted fixed abrasive chemical mechanical polishing (CMP) technique on material removal, super smooth surface and surface roughness of silicon wafer.It is considered that the path of polishing tool is the main factor to influence the material removal and surface polishing quality.Therefore, according to the experimental system, a mathematical model of polishing tool path and path density was proposed, and then the simulation models of materials removal, surface morphology and surface roughness were built.Furthermore, the experiment was launched.The present study could provide fruitful suggestion for selecting process parameters of fixed abrasive CMP technique for silicon wafer, and theoretical basis for industrial application and future experimental studies.
  • LAI Shiyang1, XIA Xiaojun2, XU Zhongming3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 244-249.
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    The wave-based (WB) technique for predicting the vibration of thin orthotropic plate was proposed.The structure wave function that exactly satisfies the global governing vibration equation of orthotropic plate was deduced.The displacement response of infinite orthotropic plate under unit concentrated force was obtained utilizing the Fourier transformation.Further, the bending vibration of the thin orthotropic plate with WBM was achieved by a weighted residual method after computing the weight coefficient of each wave function combining the physical boundary of the plate.A rectangular thin orthotropic plate was introduced as a numerical example.The wave-based technique for predicting the vibration of the thin orthotropic plate was validated by comparing with series solution, and the computational efficiency of the proposed method is much higher than the finite element method for thin orthotropic plates in mid-frequency based on convergence analysis.
  • LIU Yu1,XU Zixiang1,XU Hongbin1,2,CHEN Yajie1
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 250-256.
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    Aiming at the defect of power tillers such as violent vibration as well as poor comfort, a self-propelled power tiller commonly used in southern hilly region was studied.According to structural analysis and test results of vibration characteristics for the power tiller in the non-operational state, a new rigid-flexible coupling dynamic model of the power tiller was established based on the multi-body dynamic method with considering the influence of flexibility of the parts such as bumper-bar, E-bracket and handle.At the same time, soil test on the vibration characteristics of the power tiller was performed.The comparative results show that the vibration characteristic curve of the handle by simulation is consistent with that of the test.The error of the vibration acceleration effective value is less than 5.4%, and the spectral components are close.This indicates that the established rigid-flexible coupling dynamic model of the power tiller is effective.
  • WU Wenpeng1,2,3, LI Lifeng2, TANG Shenghua1,3, ZHANG Xuhui1,3
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 257-264.
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    In order to explore the impact of bridge modeling uncertainties on the seismic demand and improve the application of performance-based seismic design of bridges in practical engineering, a reinforced concrete continuous bridge consisting of four 30 m spans was taken as a case study.The OpenSEES software was applied to build a multiple dimension parameterized finite element model considering the uncertainties derived from structural material, boundary and the structure itself.Twenty two standardized far-fault ground motions were used to conduct the nonlinear time-history analysis.Based on the analysis results, the probabilistic stripe analysis method and the tornado diagram were adopted to investigate the sensitivity of various uncertainties.It is concluded that, the number of uncertainty parameters that affect the seismic demand prediction of the bridge is increased with earthquake intensity.The impact of the modeling uncertainties on the mean value (μ) and logarithmic standard deviation (ζ) is not consistent.Structural uncertainties have great impact on all engineering demand parameters, while the impact of the boundary uncertainty is dependent on different engineering demand parameter.Compared to the impact of the structural and boundary uncertainties, the impact of the material uncertainty is relatively less.
  • CHENG Lin, ZHAO Wenjie, LIU Tao, LIU Qihua, JIANG Yaoquan, ZHANG Xiaohu, WANG Xiaobo
    JOURNAL OF VIBRATION AND SHOCK. 2018, 37(24): 265-270.
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    In order to analyze clutch abnormal noise of a MT vehicle during vehicle launch, NVH tests were done to get the noise spectrum characteristic and several related factors were discussed.Then,the clutch system CAE model was built and dynamic clutch engagement process was simulated as well as modal optimization of the driven plate.Based on analysis process, the deep cause of abnormal noise was researched.Finally, structure enhancement of the clutch driven plate was performed.Validation results show clutch buzzing noise disappear because of the enhanced clutch driven plate.