25 August 2011, Volume 30 Issue 8
    

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  • Guang Meng;Ming-Yi You
    . 2011, 30(8): 1-11.
    Abstract ( 1627 ) Download PDF ( 1102 )   Knowledge map   Save
    Residual life Prediction and preventive maintenance scheduling are two research fields that have significant impact on the maintenance efficiency in a condition-based maintenance program. The recently published representative works in these two fields are summarized and categorized. The emerging new research fields such as similarity-based residual life prediction and on-line preventive maintenance scheduling are highlighted. The applicability of the residual life prediction techniques and preventive maintenance scheduling models are discussed. Some necessary and valuable research directions are also provided.
  • Fang hui
    . 2011, 30(8): 12-18.
    Abstract ( 1419 ) Download PDF ( 529 )   Knowledge map   Save
    This paper proposes a new method using substructure energy, which is capable of accurately estimating the damage magnitude of multiple members, and particularly advantageous for lattice structures. While other existing damage severity estimation methods require the information of several modes of the whole structure, the new method utilizes only a small number of measurement locations for lattice structures. The performance of the proposed method is compared with existing damage detection methods using a set of numerical simulations that are demonstrated for a lattice panel based on synthetic data generated from finite element models.
  • DU Jing-li;BAO Hong;ZONG Yali;CUI Chuan-zhen
    . 2011, 30(8): 19-23.
    Abstract ( 1337 ) Download PDF ( 368 )   Knowledge map   Save
    In conventional researches, cables of cable-driven parallel robots are treated as simple linear cable elements. This results in the fact that the effect of cable dynamics on the positioning precision of the end-effector is not adequately taken in account. In this paper, a dynamic model for cable-driven parallel robots with cables of slowly time-varying length is presented. The partial differential equations characterizing the dynamics of a cable with time-varying length are deduced, and converted into ordinary differential equations using finite difference method for their spatial discretization. Then, the dynamics of cable-driven parallel robots are achieved considering the couple between dynamics of the end-effector and cables, in which the degrees of freedom of cables and the end-effector are all involved. Two numerical examples are presented to validate the dynamic model in the paper, and also show that it is necessary to take into consideration of the cable dynamics for robots of large workspace.
  • Huang Jian-liang;Chen Shu-hui
    . 2011, 30(8): 24-27,5.
    Abstract ( 1216 ) Download PDF ( 1091 )   Knowledge map   Save
    In this paper, the Incremental Harmonic Balance (IHB) method is used to analysis of nonlinear vibration of the axially moving beam with coupled transverse and longitudinal motions, attention is focused on the internal resonance in the neighborhood of a 1:3 between the first two transverse modes. First, the motion equations of the axially moving beam are derived through the Hamilton’s Principle and discretized by the Galerkin’s method. Then, the IHB method is employed to solve the nonlinear vibration equations. Numerical results show the complicated frequency-amplitude response curves and effects on vibration of the axially moving beam with coupled transverse and longitudinal motions and reveal the rich and interesting nonlinear phenomena.
  • YouTian-qing;Wang Cong;Cao Wei;Wei Ying-jie;He Chun-tao
    . 2011, 30(8): 28-31,5.
    Abstract ( ) Download PDF ( 499 )   Knowledge map   Save
    While underwater launched vehicle crossing water free surface, time-varying Fluid Structure Interaction effect is formed due to the interaction between the vehicle and surrounding water and the decrease of wet surface. As a result, the variety of structure dynamic property occurs. Moreover, Compartment structure is widely adopted in underwater lunched vehicle. The joint part between two compartments causes nonlinear contact problem, which effects structure dynamic property. Considering the above factors, the vehicle is simplified into a Timoshenko beam, and mode analysis and transient analysis are conducted. The different effect regularity of the time-varying Fluid Structure Interaction and the nonlinear stiffness at the joint part on the structure natural frequency and dynamic response has been obtained. Besides, the effect of joint structure, external load and water exit velocity on structure dynamic response is analyzed.
  • XIAO Wen-bin;CHEN Jin;ZHOU Yu;WANG Zhi-yang
    . 2011, 30(8): 32-35.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Bearings are one of the key components in rotating machinery. Therefore, it is important to assess the performance degradation degree of bearings for making maintenance plans and preventing unexpected defects and breakdowns during operation. In this paper, we present a novel bearing performance degradation assessment methodology based on wavelet packet transform (WPT) and hidden Markov models (HMMs). WPT is used to extract features from vibration signals of bearings, and the node energies and the total energy are selected as features. An HMM is trained using the data under normal condition and then the trained HMM is used to assess the performance degradation degree of bearings quantitatively. A bearing accelerated life test is performed to validate the proposed methodology. The experimental results show that the proposed methodology is feasible and effective.
  • Bai Zhong-hao;Jiang Bin-hui;Zhang Qian-bin;Wen Jia-wang;Cao Li-bo
    . 2011, 30(8): 36-40.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A patented truck rear crash protective structure was designed based on crash compatibility .A finite element model of passenger Car - truck rear-end collision of this structure was built and validated in crash test. In order to improve its compatibility with passenger car, two optimized objective functions of SAE and DR were proposed According to the established optimized design parametric variables and range, orthogonal design test method was used to design16 groups of parameters and calculated with finite element simulation respectively. Then effective factors were analysed for two objectives. Finally, in order to verify the crash compatibility of the optimized protective structure, whole vehicle rear crash test was carried out.
  • Wang Jian-wei;Xu Hui;Ma Ning
    . 2011, 30(8): 41-44.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Combining experiments carried out in the workbench for the beam & plate with interior inlaid freely moving mass, the self-adaptive vibration suppression is simulated for a cantilever Euler beam with interior inlaid fluid under the first and second principal resonant excitations. A hydrokinetic model with dynamic boundaries is established by simplifying the original liquid-solid model. The simulations agree with the experiments, fully revealing the three kinds of movements for the inlaid fluid. Fluid pressures acting on the walls are analyzed, and relations between the pressures and fluid movements are also established. Compared with the vibration displacements of the beam, the pressures varying with time express a significant delay characteristic in the time domain. From the energy dissipation, a quantitative criterion is proposed to evaluate the damping effect due to the fluid movements for the simplified model.
  • ZHANG Cheng;Wu Hui;Gao Bo-qing
    . 2011, 30(8): 45-50.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on large-scale numerical calculations of different forms of grid structure subjected to earthquake, dynamic failure modes and characteristics are analyzed, assuming the failure criteria is maximum displacement exceed 1/50 of the span. Dynamic failure modes of grid structure are determined by four factors: the proportion of 8P bar, maximum displacement during full-time history, the average plastic strain energy, and the ratio of the average and maximum displacement before expiration. As the failure mode is fuzzy, the four factors are analyzed using fuzzy C-means method, and the failure modes are classified into three categories: instability-based progressive collapse, strength-based overall collapse and strength-based progressive collapse, which are described by natural and numerical language respectively. The results show that fuzzy C-means method can effectively classify the failure modes of grid structure, and transform the description from natural to numerical. The numerical prototypes of failure modes are obtained, which can be used to recognize other unknown grids, and lay the foundation for performance-based design.
  • Xiao He-ye;Sheng Mei-ping;Liu Ru-lin
    . 2011, 30(8): 51-55.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    To dissipate the unwanted vibration energy of a plate at mode frequencies, academic and experimental research of composite beam, which is used to control the plate’s vibration, are carried on. A simply-supported plate is selected as the classical object to be controlled. And finite element method is applied to design and analyze the absorption of composite beams with various cross-section unconstrained layer. Then, the experiment is operated to validate the conclusions derived from simulation. Both the analysis results and the experimental data indicate that the number of mode used to attenuate the energy of the plate and the bandwidth of the absorber grow with the increase of beam length, while the absorption at model frequencies of the beam decreases in such situation; the absorber fitted at the location near the driving point is excellent in mitigating vibration energy of plate; the lower mode of the beam is applied to absorb the plate’s energy, the greater absorption will be achieved.
  • WANG Ying-ze;ZHANG Xiao-bing
    . 2011, 30(8): 56-60,6.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The vibration response of the flexible beam under the coupled multi-moving masses with variable speeds is studied. Based on the vibration theory of the flexible beam, the vibration model of the multi-moving masses-flexible beam system is established. The interaction among the moving masses and the coupling effect between the motions of moving masses and the vibration of the flexilbe beam are considered in this model. The numerical simulation is conducted by solution method of time-variant mechanical system. Results show that the vibration response of the flexible beam is different under different forms of motion among the moving masses, and the coupling effect among moving masses enhance the vibration response of the flexible beam.
  • Guo Jun;Zhu Feng;Cui Jie;Yao Xiong-liang
    . 2011, 30(8): 61-66.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Ultimate equilibrium theory and numerical analysis are used to discuss the deformaion and damage mechanism of a beam with band plates mainly bearing shear failure, including the method calculating extreme loading; the distribution regularity of combined stress、normal stress and shearing stress along web height at several cross-sections under different loadings; the generation and expansion of plastic deformation; energy-absorbing composition analysis of the beam with band plates in the course of collision. The results can be referenced by crashworthiness structral design、assessment of crashworthiness for a finished vessel and conceptual design for model experiments.
  • CAI Jian;SHI Li-hua;YUAN Shen-fang
    . 2011, 30(8): 67-71.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Adjacent multi-damage imaging is a difficulty in the research of Lamb wave imaging. Based on the traditional “delay-and-sum” method, an improved adjacent multi-damage imaging method is proposed. To avoid or reduce the overlapping between neighboring damage scattered signals, double side excitation is adopted in the method to generate single mode Lamb wave monitoring signals with higher spatial resolution. Meanwhile, according to the energy attenuation in the propagation of Lamb waves, a compensation factor is introduced to reduce the monitoring distinctions of monitoring signals for different locations. Both theoretical analysis and experiment show that the above two improvements can enhance the imaging results of adjacent multi-damage.
  • ZHOU Da-rui;XU Guo-shan;WU Bin;TENG Jun;MA Bo-tao
    . 2011, 30(8): 72-76.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The equivalent force control method (EFCM) replaces numerical iteration with feedback control strategy to solve the nonlinear equations of motion for real-time substructure testing with implicit integration method. This paper successfully applies the EFCM for the pseudo-dynamic substructure tests of coupled shear wall structure with coupling beam damper specimen in order to investigate the seismic performance of the structure. The EFCM and the determination of some key elements in EFC were introduced, and the simplified model and pseudo-dynamic tests of the coupled shear wall structure with coupling beam damper were presented. It is shown that the EFCM can achieve excellent performance in terms of stability and accuracy if the equivalent force controller and force-displacement conversion factor were properly designed, and the coupling beam damper can effectively control the seismic response of the coupled shear wall.
  • Liu Yilun;Shi Sheng-peng;Liao Wei
    . 2011, 30(8): 77-81,9.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In response to the problems that is encountered in the process of bridge damage identification using curvature mode shapes,a formula suitable for bridge damage identification to obtain curvature mode shapes was given; curvature mode shapes normalization was proposed,in order to obtain the amount of damage easily; curvature mode variations at the curvature zero points were calculated specially,in orderc to avoid the damage identification interference from those points;and a formula for the estimation of damage amount when sensors are dense enough was given; finally numerical simulation verified the effectiveness of this method.
  • Guo Dong;Liu Jing-bo;Yan Qiu-shi
    . 2011, 30(8): 82-86,9.
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    The rebound effect of blast door is studied under the negative phase of blast loading. The reasonable approximate blast pulse shape is adopted to obtain the exact analytical formulas of rebound force for blast door, with taking into account the negative phase effect. The blast waves negative phase effect on blast door is assessed. Although the affection of rebound effect is appropriate, only the peak value of negative pressure is close to positive pressure at the condition of large scaled distance, in meantime, negative pressure shows the increasing effects on the rebound for blast door. But the response may be emerged only under the small overpressure. Due to the small peak value of both positive and negative pressures, stiffness of blast door seems to have relatively large value. The blast door would not be damaged by the increased rebound effect, therefore, the effect of negative pressure might be ignored in the design of protective structures.
  • Ji Ri-chen;Shi Ming-xing
    . 2011, 30(8): 87-91.
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    Under the guide of the existent arch bridge stability theory, the three dimension finite element model has been built for the 136m span tied-arch bridge of railway concrete-filled steel tube about the main bridge of Gechougou bridge. Its stability factor and the instability mode are given under the specific load condition. The results suggest that the structural buckling is mainly shown by out-plane buckling of the arch; elastic buckling coefficients are greater than the general requirement (4~5), which satisfies the requirement of the bridge elastic stability. Considering the nonlinear effects, after the arch ribs are progressively loaded, the ultimate loads of the arch ribs are obtained, and the vertical and transverse displacement of each controlling section when the arch ribs reach the ultimate loads. The effect of material nonlinearity on the stability of the bridge is greater than the geometric nonlinearity by comparing. According to lots of computing data, the effects of transverse brace layout, arch rib inclination angle and ratio of height to span to the stability of this bridge are revealed.
  • XU Zhong-ming;;LI Shi-sheng;ZHANG Zhi-fei;YANG Jian-guo;Li Chuan-bin
    . 2011, 30(8): 92-96.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on the working principle, the internal configuration, and the valve system behavior of the shock absorber, the equation for annular laminar deformation under a uniform load is deduced by using a deflection differential equation for throttle slice and boundary condition, according to hydrodynamics gap flow, nozzle flow and small orifice throttle theory, mathematical model of working procedure is established. The Matlab software was used to simulate a detailed model of an automotive shock absorber, the calculated results agree well with the test data. In particular, the effects and sensitivity degrees of the suction valve and intake valve on the shock absorber damping were analyzed by the model, and the obtained results provide a reference for the shock absorber design and performance prediction.
  • CAO Lu-fen;JIN Xian-long;WU Hui-ming
    . 2011, 30(8): 97-100,.
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    Explicit non-linear finite element method is applied to simulate the accident caused by the collision of transport vehicles in the construction of the long and narrow tunnel, and the impact of the accident on surrounding tunnel is analyzed. Based on the Virtual-Reality modeling, a three dimension finite element was built up as the model of large-scale water diversion tunnel of Qingcaosha and transport vehicles inside, in order to accurately simulate the impact on the surrounding tunnel caused by the collision. The three-dimensional dynamic contact method, which can simulate the actual situation of wheel slip and derail, was used to simulate the dynamic interaction between wheel and rail. Based on the contact algorithm of penalty function and the segment classification of search method, the dynamic response of the surrounding tunnel during collision was simulated. The movements of vehicles and segment, as well as the dynamic response of tunnel after collision were analyzed. The results will be helpful for prevention and treatment of such kind of accident. Parallel-computing method was used, with the computing resources of ShangHai Supercomputer Downing 5000A. The accelerating effect of parallel-computing was analyzed in the simulation of large-scale engineering problems.
  • Duan Huming; Xie Fei; Zhang Kaibin; Ma Ying; Shi Feng
    . 2011, 30(8): 101-106,.
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    It’s reviewed that the components of measurement system of road surface data and measurement methods of road surface profile in automotive test. Based on the mass road surface measurement data, some signal pre-processing methods are proposed, including the identification and correction of abnormal errors, the extraction of signal trends, the smooth connection of segment road surface measurement data, the randomness test of road surface measurement data and the processing of road surface measurement data at the moment of speed anomaly. After the introduction of these methods principle and algorithm, several actual measurement road data as examples, they show that the results of calculation and processing are significant. The test analysis and comparison results show that these methods of signal pre-processing of road surface measurement data are simple and has obvious effect. These methods of signal pre-processing can be widely applied to road surface data processing and other engineering vibration signals processing.
  • LI Li;CHEN Yuan-kun;XIA Zheng-chun;CAO Hua-jin;
    . 2011, 30(8): 107-111.
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    The galloping of iced conductors is a serious threat to the safety of the transmission lines. A two-node
    bar element having three translational and a torsional degree-of-freedom at each node was employed to model the
    conductor. Combined with the method of the bundle conductor equivalence to a single conductor, the finite
    element model of multi-span transmission line for galloping analysis was established. In addition, the
    aerodynamic coefficient of iced conductor under different wind attack angle was obtained through computational
    fluid dynamics method. On the basis of the finite element model and aerodynamic coefficient curve, the
    Runge-Kutta method was applied to carried out nonlinear numerical simulation of iced conductor galloping and
    the FORTRAN program was compiled. The galloping of the long-span transmission line crossing Hanjiang River
    was analyzed. The results indicate that the presented method and program are reliable and efficient. Meanwhile,
    the impact of the wind velocity and initial attack angle on galloping were investigated with the program. They can
    provide references for the further study of galloping.
  • Yan Zhi-tao;Li Zheng-Liang;Yang Zhen-hua
    . 2011, 30(8): 112-117.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The coupling of translational and torsional movement, the non-linearity cannot be considered in traditional galloping transmission line analytical model of 3-DOF node. Based on the strain - displacement relations of spatial curved beam theory, the finite element model of iced transmission line galloping is proposed, which contains three translational degrees of freedom and three rotational degrees of freedom. based on virtual work principle, the updated Lagrange nonlinear equations of motion iced conductor are formulated considering the aerodynamic non-linear and geometric non-linear. The Newmark time integration and the Newton-Raphson iteration method is used to solve non-linear finite element equation. An example analysis showed that the iced cable element of 6-DOF node used to calculate the static and dynamic power lines and the galloping analysis is accurate. The results of transmission line galloping analysis show that the cross-section bending modulus of the transmission line has a certain impact on translational and torsional movement.
  • ZHAO Hai-jun;DENG Zhao-xiang;LI Pei-ran
    . 2011, 30(8): 118-122.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Using orthogonal experimental design method detailed structure parameters of work piece about perforated tube muffler element are determined. Flow noise regeneration is measured on the self developing test bench. Relationship model on total sound power of flow regeneration noise and structure parameter and flow velocity is established utilizing dimensional analysis, model parameters are solved making use of hyper static least square method. Significance test of the model is performed, the law of total sound power level for muffler element flow regeneration noise changing with the parameters is discussed. Result shows that the established models are all highly significant under 0.01 levels, the reducing of the perforated diameter and the perforated part length is favor of the reduction of flow regeneration noise from perforated tube muffler element, and perforated ratio and expansion chamber diameter have less effect on flow regeneration noise. After analyzing spectrum structure of flow regeneration noise, it is indicated that with the increase of flow velocity projected peak value frequency has the trend of moving to middle and high, its strength also becomes bigger. When the range of Strouhal number is from 0.2 to 0.35, there is a peak value frequency, its sound energy in the frequency accounts for about 60% of the total energy.
  • Shi Chun-Xiang;Li Hu-Sheng
    . 2011, 30(8): 123-127,.
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    HHT is a novel data analysis method which can be used in nonlinear non—stationary data and it’s very adaptive. Fuzzy characteristics of the bridge test model and random characteristics of load excitation result in Hilbert marginal spectrum energy ratio can be disposed by random-fuzzy statistics principle, because it includes both random error and fuzzy error. The method of HHT combined with random-fuzzy statistics principle was proposed to distinguish structural damage. And four Hilbert marginal spectrum energy index were applied to the damage recognitions in a continuous two-span girder bridge model in the lab. The results indicate that four Hilbert marginal spectrum energy index all changed before and after girder damaged, but energy accumulated variation index and energy variation max index can denote damage location and extent accurately, are more sensitive than energy ratio deviation and energy ratio variance to the structural damage, so they are more applicable in the bridge online alarming system.
  • CAI De-yong;MA Da-wei;ZHU Zhong-ling;REN-Jie
    . 2011, 30(8): 128-132.
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    Establish the dynamic model of the folding empennage mechanism,the folding empennage unfolded motion law was obtained . According to design requirements of empennage mechanism and design criteria of torsion spring , the optimization model of the driving torsion spring parameters was established. Using Simulated Annealing Algorithm(SAA), the optimal parameters of torsion spring is obtained by computer program using Visual Basic. The finite element model of folding empennage mechanism was established, the numerical simulation of original and optimized design parameters were carried out . Simulation results show that the impact load of the optimized design decreased by 23.2% with the empennage unfolded time meeting the design requirement.
  • Du Heng;Wei Jian-hua
    . 2011, 30(8): 133-138.
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    In order to improve engineering vehicle road comfort and road-friendliness, co-simulation model with ADAMS/Simulink/AMESim and multi-objective optimization function were established based on 7-DOF whole vehicle interconnected hydro-pneumatic suspension model with considering of the nonlinear characteristic of all components and four-wheel road signal correlation. Co-simulation optimization was achieved by genetic algorithm. The results show that total weighted RMS acceleration of vehicle body decrease by 42.5% and road-friendliness factor decrease by 4.5% compared with the former in the case of speed 60km/h. Road comfort has been greatly improved and road-friendly factor has been slightly improved. Vehicle ride comfort and road-friendliness can be both improved by multiple software co-simulation based on genetic algorithm. The work presented in this paper can be used for the simulation research of multi-axis chassis performance improving in the future.
  • GAO Hao-peng;HUANG Ying-yun
    . 2011, 30(8): 139-143.
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    With the instruction of computational dynamics of multi-body systems theory, and at the background of shock resistance study on diesel generator of marine, the multi-body dynamics systems of diesel generator and linear vibration isolation system were molded. Then, these models were confirmed by the diesel vibration intensity experiment. Based on these factors, the non-linear vibration isolation system was constructed, then, the dynamic characteristics were analyzed when the diesel generator worked on rated condition and under impact loads. The results indicated that the effect of non-linear vibration isolation system was better than linear vibration isolation system. Compared with the mathematic method, the modeling and solution method in this paper can be easily realized. This method can be widely used in the process of model selection and vibration isolators fixing, in the aspects of parametric design and optimization, and in the shock resistance study of other mechanism.
  • Yang Fu-chun;zhou Xiao-jun;zheng Jin-yang
    . 2011, 30(8): 144-148.
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    Comprehensive dynamic model of complex compound planetary gear set was established considering translational, rotational vibrations of each component and static transmission errors. Band distribution characteristics of its eigenvalues was researched. According to vibration characteristics of central components (CC) and planets (Ps) vibration modes were classified into three types: CC translation and Ps stochastic vibration mode, CC rotation and Ps uniform vibration mode, CC stationary and adjacent Ps reverse vibration mode.
  • LI Guo-bin; GUAN De-lin; LI Ting-ju
    . 2011, 30(8): 149-152.
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    In order to recognize the operating conditions of diesel engine, a novel approach for extracting feature of vibration signals was proposed using waveletpacket transform and singularity value decomposition. The waveletpacket transform and the singularity value decomposition arithmetic were introduced. The characteristic parameters were defined based on the singular value characteristic vector. The intrinsic relationship between the characteristic parameters and the operating condition of diesel engine were discussed. It has been shown that the characteristic parameters can sensitively reflect the working performance of diesel engine. When the working performance of diesel engine turns for the worse and the intensity of vibration increases, the characteristic parameters appear larger. Therefore the characteristic parameters could be considered as parameters to inspect and diagnose the state and the fault of engine.
  • Zhang Hai-tao; Ding Qian;
    . 2011, 30(8): 153-156.
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    Self-excited vibration induced by dry-friction of a block-on-belt model is studied in this paper. The stability of fixed point of the system is analyzed first. Then the self-excited vibration of the system, including pure slip type and stick-slip type, are investigated by the homotopy method. The second or the third-order analytic approximate solutions can be obtained with high precision, in which the motion characteristics of the system are revealed, by properly choosing the base function sets, initial guess of the solution and auxiliary linear operator respectively. For the stick-slip limit cycle composed by one slip stage and one stick stage, the approximate solution of the slip stage during one period contains secular terms.
  • Zhang Liang-xin; He Xue-jun;Ren Ai-di
    . 2011, 30(8): 157-160,.
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    A nonlinear dynamic model of in-plane motion for highline cable system of alongside replenishment was formulated, which considered the influence of the lumped mass on highline cable. The partial differential equation was discretized into ordinary differential equations by Galerkin approach and the standard dynamic equations of highline cable were acquired. The influence of the position of lumped mass on the first three modal frequencies was analyzed during the course of alongside replenishment and the modal frequencies had nonlinear hysteretic characteristic. The dynamics for parametrically excited highline cable system with 1:1:2 internal resonance and 1:2 internal resonance were analyzed numerically, and time history curves, phase trajectories of which were obtained up to the third model. The results show that there exist complex dynamic behaviors such as multiple period motion in internal resonant cases, and the first two models were dominant in the in-plane oscillation of highline cable system. Whereas only the first model was dominant in the in-plane oscillation of highline cable system with 1:2 internal resonant, and the first modal oscillation was periodical.
  • PIAO Ming-wei;LIANG Shu-lin;KONG Wei-gang;ZHAO Wen-zhong
    . 2011, 30(8): 161-168.
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    In order to satisfy the safety stability-margin requirements of the new-generation high-speed bogies, based on the exploration of bogie frame acceleration alarm, the yaw soft constraint solutions and their technical implementation steps were presented. The running stability analysis is the synthesis evaluations included critical velocity and dynamical behavior. The critical velocities depend on the W/R matching features, and are influenced remarkably by the non-linear variation of both W/R contacts and bogies. The dynamical behavior evaluations are the safety index ones of bogie’s frame lateral acceleration, etc. Due to the anti-hunting dampers having the high-frequency blowing-off mechanism, the safety limits can also be reached or exceeded by the dynamical behavors of trailer bogies in spite of the small amplitude of hunting wheelset under the subcritical bifurcatuion. The frequency response analyses of bogie’s frame lateral accelerations show that the hunting oscillation is the main resonance in their vibration frequency responses, which can be controlled by the yaw soft constraint solutions.
  • ZHONG Yi-feng;YU Wen-bin
    . 2011, 30(8): 169-174.
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    In order to effectively analyze the thermal post-buckling performance of antisymmetric angle-ply composite laminates, the two coupled fourth-order governing partial differential equations, namely, the compatibility equation and dynamic governing equation, were deduced from the asymptotically correct, geometrically nonlinear theory. A relatively simpler solution method was developed to solve those equations by transforming the coupled nonlinear governing equations into a system of nonlinear ordinary differential equations and using double Fourier series. The generalized Galerkin method was used to solve boundary value problems corresponding to antisymmetric angle-ply composite plates. The post buckling patterns with different complex before and after mode jumping were analyzed. An example of 4-layers composite laminates under simple-supported, in-plane constrained boundary condition shows that the numerical results in the primary post-buckling region from the present method agree with the finite element analysis (FEA); while the FEA may lose its convergence when solution comes close to the secondary bifurcation point, the analytic method has the capability to explore deeply into the post-secondary bucking realm and capture the mode jumping phenomenon.
  • Guo Bei-tao;Liu Hong-yi
    . 2011, 30(8): 175-178,.
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    The causes of pulsation in fluid system of solenoid valve test-bed are discussed in this paper, and frequency characteristic is used to calculate and simulate for main test pipeline. The better parameters of structure and components are chosen and also the corresponding elimination measures are took based on above theoretical analysis. These measures could deduce and eliminate the pressure pulsation effectively and prevent resonance, which can be applied in similar fluid control and test system and has some value in engineering application.
  • GONG Ran;GE Ru-hai;XIE Ming-xiang
    . 2011, 30(8): 179-182.
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    A coupled method based on the small perturbation method and numeric computation was presented to estimate stability and dynamical response of seals assembled in the transmission of vehicle. According to the working conditions of sealing rings, the stiffness and damping coefficients of a fluid film was calculated with three degrees of freedom for a face seal. With the analytical model for dynamic parameters built and the time-variant Reynolds equation solved by numerical method, the relationships between angular perturbations and deflection torque was discussed. The variable curves of the stiffness and damping coefficients with pressure and rotating speed were obtained, and the real impacts of sealing face wear were predicted. Numerical results show that the fluid film thickness has a significant influence on the stiffness and damping coefficients, and when it increased, the sealing unstabilizing factor also increased. The stiffness coefficients increase fairly rapidly with the increase of pressure and rotating speed especially where Pv value is bigger. So it’ll add to the advantage of the prevention of seal wear to control fluid film thickness and rationalize the pressure and rotating speed of transmission appropriately.
  • LUO Li-ping;YU Yuan-hong
    . 2011, 30(8): 183-186.
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    The (strong) oscillation of solutions for the systems of a class of quasilinear impulsive neutral parabolic partial differential equations with quasilinear diffusion coefficient is studied. By using the oscillatory definition, Greens formula and Newmann boundary condition directly, the oscillatory problem of solution to the systems of impulsive neutral parabolic equations is reduced to the problem of which impulsive neutral differential inequality hasnt eventually position solution, and thereby some sufficient criteria are obtained for the (strong) oscillation of such systems via the definition of eventually position solution and impulsive neutral differential inequality. The obtained results fully reflect the influence action of impulses and delays in oscillation.
  • Cui Xiao-bing;Ji Zhen-lin
    . 2011, 30(8): 187-192.
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    The numerical calculation of multipole expansions in FMBEM was investigated, the models of four points translation relationship to single level and multi-level were built. According to comparing with the theoretical value of Green’ function and it’s normal derivative, the computational accuracy of multipole expansions in sound-absorbing materials and air was studied under the two relationship. Results indicated that, the computational accuracy which was derived from the calculation of expansions with complex wavenumber was related to the value of truncation number, when the product of wavenumber’s imaginary part and the distance of transitive points was too big, the expansion’s value began to go far away from the true value. Finally, two methods were proposed to solve this problem. Furthermore, the transmission loss of a dissipative expansion chamber silencer was calculated as an example, the availability and the feasibility of present paper’s methods were validated.
  • Tan Dong-mei;Qu Wei-lian
    . 2011, 30(8): 193-198.
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    The finite element model correction method of truss structure based on lifting wavelet packet transform and fuzzy pattern recognition is presented. Firstly, the element stiffness matrix of spatial truss is established using the joint fixity factor. Secondly, the vibration signal is decomposed using lifting wavelet packet (WP) analysis based on lifting scheme, and then the corresponding characteristic vector is established by the lifting WP component energy, which can be used as the subset of fuzzy pattern recognition. Finally, the finite element model is updated using fuzzy pattern recognition, and the effect of noise on the algorithm is also studied. In order to verify the proposed method, the numerical research on a two-story truss structure model is carried out. The numerical results show that the proposed method can be effectively used to correct the finite element model.
  • TANG Shun-yong;LI Hong-nan
    . 2011, 30(8): 199-202.
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    Taking a 500kv high-voltage transmission tower in Shenyang as the prototype, they introduce aeroelastic modeling of high-voltage transmission towers,which meets the similarity theory for wind tunnel tests. It provides a feasible method for aeroelastic modeling. A formula for the pressure of rain loads is put forward. Through pressure scale ratio is equal to geometry scale ratio, they get a formula for scale ratio of wind-rain loads first in wind tunnel tests. In the actual wind tunnel tests, they suppose diameter of simulation for rain loads in the wind tunnel is equal to diameter of the actual rain loads. They get number density of simulation for rain loads in the wind tunnel is equal to the number density of the actual rain loads.
    This method is simple, and provides a theoretical basis for the wind-rain loads simulation in the wind tunnel tests.
  • LIU Yuan-fang;BAI Hong-bo;LI Dong-wei;WANG You-yan;TAO Shuai
    . 2011, 30(8): 203-206,.
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    Based on the analysis of a great deal of experimental data,a method of establishing three-dimensional dynamic model of restoring force of metal rubber is presented.Through interpolation fitting of experimental data and theoretical analysis,the analytic equation in which the relationship of velocity,displacement and restoring force is described is built.We consider that restoring force is composed of three components which are respectively linear elastic force with positive stiffness , non-linear damping force and non-linear elastic force with negative stiffness which is related to the square of the velocity.The physical meaning of the three components is analysed.Experimental results indicate that the proposed model can describe and analyse the restoring force of metal rubber more intuitively and exactly.The disadvantage that the present models are simple and the parameter identificating is complex is overcome.
  • SHAO Jun-peng;XU Bin
    . 2011, 30(8): 207-211.
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    In order to reduce vibration of grinding head of swing-style tile polishing machine, the existing grinding head was improved. Exciting force equation of grinding head with after improvement Vibration reduction mechanism of grinding head with after improvement was discussed. A series of comparative vibration acceleration experiments of grinding head with after improvement is performed, the vibration performance of grinding head with u after improvement is better than that of grinding head with before improvement, the ability of reducing vibration is very effective.
  • CHEN Shuang-xi;LIN Jian-hui;CHEN Jian-zheng
    . 2011, 30(8): 212-216.
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    In order to extract dynamic characteristics of vehicle-track coupling system, the Improved Empirical Mode Decomposition was presented. In this method, extremum points envelopment mean were replaced by improved extremum field mean and the boundary wave matching algorithm was used to restrain the end effect. Based on the theory of vehicle-track coupling dynamics, the vertical vehicle ballastless-track coupling dynamics model was established. Under the rail corrugation and rail irregularity excitation model, dynamic responses of vehicle-track coupling system were calculated at different speed. These dynamic responses were decomposed by Improved Empirical Mode Decomposition, and then the intrinsic mode functions of vertical contact force, bogie acceleration, and car body acceleration were analyzed and compared. The results show: the Improved Empirical Mode Decomposition can self-adaptively decompose vibration signals to intrinsic mode functions and so effectively extract dynamic characteristics of vehicle-track coupling system.
  • SHANG Chao;ZHANG Jia-zhong;Cao Wei;Yu Kai-ping
    . 2011, 30(8): 217-220.
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    The absorption characteristics of the mixed-cavity structure anechoic coating with air backings is studied based on the finite element method. The absorption characteristics of anechoic coating with mixed-cavity structure were studied. The calculation result indicates that the absorption characteristics of this kind of cavity structure are superior to single-cavity structure under the same perforated percentage. Then, the absorption properties of anechoic coating with mixed-cavity structure at full-frequency range were further improved by optimization design. The influence of coating structure parameters on absorption characteristics is studied.
  • Jia-yan Lei; Qian-feng Yao; Ying Lei; Chao Liu
    . 2011, 30(8): 221-224,.
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    A structural damage identification technique based on correlation function analysis of vibration measurements is proposed. An 8-storey steel shear building model has been chosen as the case verification. The results demonstrate that accident change of correlation function amplitudes can be used to locate the damage by comparing the shape changes of damaged and undamaged samples. The value of is effective to determinate that whether the damage has happened or not, and it can be used as a reference method even for structural health monitoring on-line. The parameter K, defined to detect damage degree, corresponds to the theoretical damage level in different cases.
  • HU Bo;YANG De-Sen
    . 2011, 30(8): 225-229.
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    In statistically optimized near-field acoustical holography (SONAH), the reconstructed acoustical field is obtained by a linear combination of the measured sound pressure data on the holographic surface, so it could overcome the limitation of FFT-based NAH. Appling this method to identify the noise source in underwater cylindrical sources, the principle of the statistically optimized cylindrical near-field acoustical holography based on measurement of pressure and particle velocity was presented. The numerical simulations have been conducted. At last, the validity and correctness of vector hydrophone array is assessed by underwater near-field acoustic holography experiments. The results of experiment using vector hydrophone array show the merits of the underwater NAH in the reconstruction of sound field, identification and localization of the noise sources.
  • Deng Yang;Ding You-liang;Li Ai-qun
    . 2011, 30(8): 230-236.
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    This paper investigates the measured variability in modal frequencies of a suspension bridge induced by temperature, wind, traffic loadings and identification algorithm simultaneously making use of long-term monitoring data. First the seasonal temperature-frequency correlation is formulated using multi-sample averaging technique to reduce the random variations rising from the identification algorithm. Then the effect of temperature on the measured modal frequencies is eliminated by normalizing these modal frequencies to a reference temperature. The traffic-induced modal variability is further quantitatively evaluated under weak wind conditions by correlation the normalized modal frequencies with the root mean square (RMS) of acceleration responses. Based on the traffic-frequency correlation models, the effect of traffic loadings on the modal frequencies is eliminated and the wind-induced modal variability is quantitatively evaluated. The results indicates that the technique proposed in this study can effectively give a quantitative evaluation of measured variability in modal frequencies of long-span bridges and however at present it still needs to improve the identification algorithm of the modal frequency.
  • Liu Jingping;Deng Banglin;Du Biao;Feng Renhua;Xu Sheng-li
    . 2011, 30(8): 237-242,.
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    A modal and forced vibration analysis of the exhaust system of a car is carried out by using of Finite element software and AVL-Excite. First, a free modal analysis on the exhaust system is carried out by using of Finite element software; a preliminary analysis of reasonableness of the drop zone layout of the exhaust system is carried out. Then the Finite element software is used to reduce degrees of freedom, to extract the mass matrix, stiffness matrix, the main node degree of freedom of information and mode information of the exhaust system, and integrate these into the internal combustion engine - the exhaust system multi-body dynamic model, carry out the forced vibration analysis of the exhaust system, the impaction of the elastic deformation and modal resonance on vibration is fully considered. Vibration at any point of the exhaust system and the vibration transmissibility on the length of exhaust pipe is obtained, and its vibration coupling characteristics is studied; then a strong basis for space direction and structural design of the exhaust system can be provide.
  • Liu Yue;ZHANG Zhi-tian;CHEN Zheng-qing
    . 2011, 30(8): 243-248.
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    Aerodynamic derivatives of a thin flat plate and a bridge girder section are recognized through forced vibration method in wind tunnel and CFD dynamic meshing simulation, respectively. Results indicate that, with the case of the stream line section, numerical results of CFD simulation are in good agreement with those obtained by wind tunnel test. In the case of box girder section there exists some obvious discrepancy between CFD numerical simulation and wind tunnel test, characterized by two errors in low reduced wind velocities and large errors in high reduced wind velocities. In order to increase the precision of CFD identification of aerodynamic derivatives for bluff sections, refined spatial grid and prolonged computing time are needed at the expense of precious computing time. Thus, a conspicuous disadvantage exists in the present CFD numerical method in the identification of aerodynamic derivatives of bluff girder sections, especially the stability and efficiency of the CFD algorithm. In the view of this, the CFD method cannot supplant the physical wind tunnel test for the moment when the fluid-structure interactions of blunt bridge section are involved.
  • OUYANG Tao;GUO Wen-li;DUAN Fa-jie;LI Meng-lin
    . 2011, 30(8): 249-252,.
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    In order to command the vibration characteristic of the rotating blades at different speed, the blades vibration testing experiment has been taken by BTT (blade-tip-timing) system. Speed-vector-end-tracking method based on varying speed measurement is analyzed in theory. And a new method for identifying blades synchronous vibration is designed. The method is applied on a certain model of aerial equipment to do measuring experiment. The vibration parameters such as engine-order, dynamic frequency, amplitude and damp coefficient have been identified exactly. The identifying repeatability error of the frequency and amplitude are up to 0.0072Hz and 5.7um. Blade Campbell diagram has been drawn correctly. The experiment identified results are in accord with the designed results of the blade in theory.
  • Tao Shuai; Bai Hongbai; Gu wei
    . 2011, 30(8): 253-257.
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    A type of composite piezoelectric actuator with an elastic solid and a piezoelectric connected is designed, which could control the active micro-vibration isolation platform in a wide frequency. When the composite actuator is used in the micro-vibration isolation platform, it is found that the relative position of elastic body and piezoelectric part would affect the control force when the platform falls under different kinds of external disturbance. So, an evaluation function of the control force is built to evaluate the differences caused by different relative positions when the platform has directly and ground disturbance. The simulation result shows that the relative position of elastic solid and piezoelectric part affects the control force indistinctively when the platform has ground disturbance only, but the effect is distinct when the disturbance input is direct disturbance only, which means that the composite piezoelectric actuator element’s relative position is decided by the disturbance, and if the two styles of arrangement in the platform would gain the same isolation effect under the circumstance of laboratory ,the energy’s consumption with the elastic solid above the piezoelectric is less than that below.
  • wang Qi-shen;Wang Yang;He Min;Qian Hua-feng;Liu Quan-jin
    . 2011, 30(8): 258-263.
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    We researched the inverse problems in vibration of a membrane in this paper. First, using the second-order center difference scheme, the difference discrete model of the axial symmetry vibration of the circular membrane with arbitrary supports is established. Second, we pointed to this model belonged to the positive Jacobi system and obtained some qualitative properties of the axial symmetry vibration of the system. Furthermore, the inverse frequency problem and inverse mode problem of the circular membrane with the fixed and/or the spring supported boundary are raised. These new inverse problems are solved successfully with the aid of the results on the inverse problems of the Jacobi matrix. Finally, we gave three examples of the numerical computation. The coreectness of the formulation and solving method of the inverse problems are verified.
  • Cao You-qiang;Deng Zhao-xing;Wang Pan;Li Jun
    . 2011, 30(8): 264-268.
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    An optimization algorithm which is composed of particle swarm optimization(PSO) and sequential quadratic programming (SQP) algorithm is presented for the multi-Parameter, multi-objective,nonlinear optimization of ADF model of structure damping material. The results are compared with those of standard rheologic model and fractional derivative model as well as the experiment results. Based on the ADF mathematical model, the dynamic models of viscoelastic lumped parameter system and damping sandwich board are established, and the modal analysis and damping prediction are done. The results show that this method can not only obtain the better optimum solution, but also get the accurate and reliable value which will correctly describe the constitutive characteristics of damping material.
  • TANG Ye;FANG Bo;ZHANG Ye -wei;LI Qing-fen
    . 2011, 30(8): 269-274.
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    The nonlinear behaviors of cantilever pipeline conveying fluid system, under the excitation of pulsating fluid and harmonic motion of the base are investigated to find out the law of system motion. The differential equation of cantilever pipeline conveying fluid motion with nonlinear spring support is established, and the nonlinear differential equation of motion is discretized by the Ritz-Galerkin method based on the natural frequency and eigenfunctions of cantilever beam which is regarded similarly under the linear spring support condition. Through numerical calculations, the nonlinear dynamic responses of system are analyzed by bifurcation diagrams, phase portraits and power-spectrum portraits. The laws that the average velocity of fluid and the mass ratio of fluid and pipeline have an important effect on the periodic motion and the chaotic motion of system are obtained. The results obtained show that the behavior of system response is the periodic motion when the average velocity of fluid is relatively little. The response of system gets into the chaotic motion via series of period-doubling bifurcations, and it changes into the periodic motion via series of inverse period-doubling bifurcations with increase in the average velocity of fluid. When the system turns up the chaotic motion, the critical value which is the average velocity of fluid decreases with decrease in the mass ratio of fluid and pipeline. This shows that the vibration mode of system can be controlled by changing the parameters for mass ratio of fluid and pipeline.
  • PENG L X
    . 2011, 30(8): 275-281.
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    A moving-least square meshfree method for the solution of free vibration problems of folded symmetrically laminated plate structures is introduced in this paper. Employing the meshfree folded plate model proposed by the author, a folded laminated plate is simulated as a composite structure of the laminates lie in different planes. Based on the first-order shear deformation theory (FSDT) and the moving-least square approximation, the stiffness and mass matrices of the laminates are derived and supposed to obtain the stiffness and mass matrices of the entire structure by implementing displacement compatible condition among the laminates. The governing equation on the free vibration behavior of the folded laminated plate is thus established. fields of the plate and rib(s) are established. Because of the meshfree characteristics, no mesh is involved to determine the stiffness and mass matrices of the laminates in this paper. Hence the troublesome remeshing is removed completely from the study of such problems as the large deformation of folded laminated plates. Numerical examples show good agreement between the solutions given by the proposed method and ANSYS, using shell elements, which proves the validity of the proposed method.