25 March 2011, Volume 30 Issue 3
    

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  • GUAN Guang-feng;WANG Haitao;XIONG Wei
    . 2011, 30(3): 1-04.
    Abstract ( 1415 ) Download PDF ( 650 )   Knowledge map   Save

    The real time adaptive control algorithm of power spectral density (PSD) replication is presented based on Kalman filters to improve the control precision of the vibration control system. The finite impulse response (FIR) filters are designed with the reference PSD. The time domain drive signal is generated by filtering a series of independent white noise with the designed FIR filters. The Kalman filters are developed to obtain the inverse model of the vibration control system. The input signal of the vibration control system is updated based on adaptive inverse control method. The reference PSD is replicated in high precision by the reproduction of the time domain drive signal in the output of the system. The test results of PSD replication show the effectiveness of the proposed algorithm.

  • DENG Lei;Fu Weina;Dong Shaojiang;Tang Baoping
    . 2011, 30(3): 5-09.
    Abstract ( 1630 ) Download PDF ( 996 )   Knowledge map   Save
    Combined with vibration signals characteristics during run-up or coast down of rotating machinery, a novel order tracking method for rotating machinery based on tacholess and Vold-Kalman order tracking filtering technique is proposed. The instantaneous frequency is estimated by the energy centrobaric method, then the order components from vibration signals can be extracted by the Vold-Kalman order tracking. Compared with conventional methods of Vold-Kalman ordering tracking technology, the proposed method has high precision in algorithms with no aid of tachometer and other special hardware. Results of simulation and application show that the proposed method could, in time domain, extract precisely the amplitude and the order components of varying frequency.
  • Wang Min;Shi Shaoqing;Kang Jianggong
    . 2011, 30(3): 10-13,2.
    Abstract ( 1024 ) Download PDF ( 812 )   Knowledge map   Save
    The formula to consider the dissipation energy capacity of the single ring is deduced, and the two models of the ring net with different restraint impacted by rockfall are established, the dissipation energy capacity of the ring net in two models is discussed. Based on the LS-DANY program, the mechanical performance about the ring net in the two models impacted by rockfall is researched, and the result of model one is validated by the experiment. The parameters which influence the dissipation energy capacity of the ring net in the model two are analyzed, and the result is compared with the theory. The research shows that the theory can evaluate the dissipation energy capacity of the ring net. The way to evaluate the dissipation energy capacity of the ring net is presented.
  • DENG Rong-bing;JIN Xian-long;CHEN Jun
    . 2011, 30(3): 14-17,2.
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    The arbitrary Lagrangian Eulerian method is applied to simulate dynamic interaction between explosive wave and complex curtain wall. Based on explicit finite element method and blast test, two-step simulation method is developed by using MPP LS-DYNA software on a high performance computing platform in order to improve computational efficiency in blast-structure problem. The dynamic response of glass in the curtain wall under blast loading is analyzed and numerical results are in agreement with the experiment. The analysis provides reference for the blast resistance design and improvement of curtain wall system. The presented method is shown to be a useful tool for documenting the blast response of curtain wall system and provides reference for the blast resistance design of curtain wall in the real-world explosive environment.
  • LIU Yu;DU Changlong;FU lin;GAO Kuidong
    . 2011, 30(3): 18-21.
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    Impact-crushing velocity is the principal parameter influencing lump-coal impact-crushing effect. When lump coal impacted the rigid plate, the contact stress was presented based on piecewise plastic-deformation model. The impact velocity crushing lump coal into a certain size was derived theoretically by crack hypothesis and energy conservation principle. The experiment fitting formula was proposed out through lump-coal impact-crushing experiments, so the theoretical modified formula did. Compared with experimental results, 88% fitting values’ errors are less than 10%, while 85% theoretical modified values less than 20%. The analysis results shows that the fitting formula are too complex to engineering application, the theoretical modified formula can meet the accuracy for primary crushing and may be as theoretical selection rules for impact-crushing velocity.
  • LIAO Haitao;WANG Jianjun;LI Qihan
    . 2011, 30(3): 22-29.
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    The worst mistuning pattern and robust maximum mistuned forced response of a mistuned multi-stage bladed rotor are studied as an optimization problem. This approach is simulated on both a lumped parameter model of a mistuned multi-stage bladed rotor and a three-degree-of-freedom per blade disk model. Results of the optimum search of the worst-case mistuning patterns for the lumped parameter models are analyzed, which reveals that the maximum blade forced response in a mistuned bladed disk is associated with mistuning jump which causing strong localization of the vibration re-sponse in a particular blade. The three-degree-of-freedom per blade disk model is also used for calcu-lation of the maximum forced resonant response of mistuned assemblies and for determination of its sensitivity coefficients with respect to mistuning variation. Studies show that there is not a threshold of mistuning beyond which the maximum forced response levels off, or even drops, as the degree of mistuning is increased further, the tendency of the forced response maximum amplitude magnifica-tion to increase with blade mistuning. The influence of the multi-stage coupling is revealed by com-paring the results of single stage analysis with that of the multi-stage case.
  • Sun He-yang;Ma Ji-sheng;Li Wei;Liu Hai-ping;Qi Qi
    . 2011, 30(3): 30-33.
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    Based on the elastic-plastic contact finite element theory, an initial damage,progressive damage and failure constitute model of the band was introduced. Explicit dynamic finite element model was built and the impacting and engraving process of the band was analyzed. The impacting and engraving processes for two different structure of bore were computed and their dynamic responses were obtained. The influence of different structures of bore to the impact force was analyzed and the mechanism of crack initiation was revealed.
  • Lv Rui;Wei Ying-jie;Yu Kai-Ping;Zhang Jia-zhong;Wang Jing-hua
    . 2011, 30(3): 34-37,4.
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    When a supercavitating vehicle runs in cruise phase, it has different characteristics from usual underwater vehicles, and is acted by the perturbation of the hydrodynamic coefficient and the unknown disturbance on its tail. These problems bring great difficulties for designing stability controller. The mathematical model of supercavitating vehicle was improved, and the global sliding mode function was designed. Upper bound of uncertain factors was estimated by using adaptive arithmetic here, and the variable-structure controller was designed, and mathematical simulation was performed for supercavitating vehicles with the controller. The simulation result demonstrates that the system responds rapidly and has good robust stability.
  • Zhao Wan;Guang Meng;Jian Ping Jing;Hui Yu Bai
    . 2011, 30(3): 38-41,5.
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    An unbalanced dual–disk rotor–bearing model was built to study the dynamic behaviors of the rotor of a real gas turbine generator. Parameters were carefully set based on the running conditions and structure characteristics of the generator. A systematic numerical analysis was done and the results clearly show that the whirl development of the rotor can be divided into three stages as speed rises: 1) stable synchronous inertia whirl stage; 2) self-excited oil whirl and accumulation stage, at which the vibration energy transfers from inertia whirl to oil whirl; 3) instable oil whip stage. The characteristics of each stage are discussed comprehensively. Special effort was done to study the influence of unbalance to the whirl progress, amplitude spectrum and stability of the system. The results are verified by several experimental studies. It shows that the model in the paper can be used to analyze the integrated dynamic behaviors of gas turbine rotor.
  • Shen Hui-jie;Yu Dian-long;Wen Ji-hong;Chen sheng-bing;Wen Xi-sen
    . 2011, 30(3): 42-46.
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    Longitudinal vibration and flexural vibration in a bend pipe system is studied. The bend pipe is modeled as a periodic composite materials structure based on the Bragg scattering mechanism of Phononic Crystals, and then obtain the Bragg band structure. Using a transfer matrix method, the frequency response functions (FRFs) of longitudinal vibration and flexural vibration are calculated to study the vibration transfer properties of the Bragg periodic L-shaped pipe. The correctness of the transfer matrix method is proved by the calculation of commercial software MSC.Patran. The effects of damping factor on the frequency response function of pipe vibration are considered. The periodic bend fluid pipe may be effective in vibration reduction in a complex pipe system.

  • Guo Chao-yang;Zong Lu-hang;Chen Xian-min;Li Jian-feng;Xue Qun;Feng Jiang-hua;Gong Xing-long *
    . 2011, 30(3): 47-52.
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    A kind of inner-pass magnetorheological (MR) damper is designed, whose damping passage is in the electromagnetic coil and the regions of the MF effect are in the fixed gap between two parallel disks. The dynamic and response time of MR damper are tested by using a material test system (MTS) load frame. To simulate the vibration of the high speed train, a platform of double mass spring system is built, and with skyhook control damping effect of the MR damper is study, which shows that MR damper is effective for vibration reduction at the frequent from 1Hz to 2Hz.
  • ZHAO Fengqun;WANG Zhongmin
    . 2011, 30(3): 53-59.
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    nonlinear vibration of simply supported FGM rectangular plates subjected to uniformly distributed tangential follower forces is presented in this paper. The material properties of a FGM plate were graded continuously in the direction of thickness, according to a simply power-low distribution of the volume fraction of the constituents. The governing nonlinear partial differential equations which expressed by stress function and deflection function are obtained using the von Karman theory. Then the nonlinear partial differential equations are transformed into ordinary nonlinear differential equation using Galerkin method. For simply supported ceramic/metal FGM plates under the action of uniformly distributed tangential follower forces, the effect of follower force, gradient index and aspect ratio on the dynamic behavior of the plates is discussed. The relation between central amplitude and nonlinear fundamental frequency for different parameter are derived.
  • GE Zhen-liang;HOU You-shan;JIANG Yong
    . 2011, 30(3): 60-63,8.
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    Based on power bond graph diagram method,the general mathematical model of full hydraulic steering system(FHSS) is established.The dynamic characteristics of hydraulic pipes of the FHSS and the influence of the pipeline parameters on the steering system is mainly analyzed by using 20sim bond graph software.The study results show that for the long and small diameter pipeline steering systems, the fluid resistance and fluid sense get larger,whice is conductive to suppress high-frequency system oscillation and shock to enhance the stability of steering system, but also extends the system's dynamic response time; for the short and big diameter pipeline, the fluid resistance and fluid sense get smaller,the System dynamic response is rapid, but the steering system has a intensive high-frequency oscillation,the oscillation amplitude and frequency increase,which is unconductive to the stability of steering system. Increasing the volume of oil elastic modulus of the system to improve the dynamic response speed and stability. The study results provide a theoretical support for the design of the full hydraulic steering system and pipeline nets’dynamic characteristics analysis.
  • WANG Shi-long;LEI Song;ZHOU Jie;LI Chuan;YANG Yong;XIAO Hong
    . 2011, 30(3): 64-68.
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    Stranded wires helical springs of closed ends in practical work are used as return springs to bear the impact load. Based on the problem, the centre line mathematical model of stranded wires helical springs of closed ends was presented at first. Taking use of the software CATIA and ABAQUS, the three dimensional geometrical model and the FEM impact model of a stranded wires helical spring of closed ends were set up respectively according to the centre line mathematical model to calculate the impact response. The results show that when stranded wires helical springs are impacted, every spring coil will vibrate, and the movement of every spring mass point will transmit to the fixed end in the form of longitudinal wave and reflect in both fixed end and active end. The relationship between displacement and axial length of every spring mass point is non-linear, the same to that of velocity and axial length. There is large deformation in the active end, on the contrary, little deformation in the fixed end. Some spring coils will be pressed together when the impact load exceeds the limiting value. In practical design work of stranded wires helical springs, in order to select the reasonable stiffness and to avoid the phenomenon of being pressed together of some spring coils, it is necessary to analyze the impact response.
  • Chen Jia-yan;Wang Hai-dong;Zhou Jian-chuan;He Hui-nong;Chen Zhang-wei
    . 2011, 30(3): 69-73.
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    More and more people have attached greater importance to the multi-exciter vibration testing system since it can be able to simulate the vibration environment more real, and now it has become a development tendency of environmental vibration test. The basic control principle of multi-exciter vibration testing system,and key technologies of time-domain waveform replication , which includes iterative algorithm and overlap connective of driving signal, and frequency spectrum replication, which includes feedback correcting algorithm and time randomization are introduced in this paper. At last, this paper gives a summary and prospect of control technology for multi-exciter vibration testing.
  • HE Jingfeng;LI Baoping;TONG Zhizhong;YANG Hongbin;HAN Junwei
    . 2011, 30(3): 74-78.
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    A shaking table is an important facility for earthquake damage testing of large scale structures like high buildings, large bridges and infrastructural systems. To improve the payload capacity for the test for large-scale structures or real-scale structures, hydraulically redundant actuated parallel mechanisms are usually adopted. In the present paper, by exploring the interactions between the mechanical parts and the hydraulic actuated systems, an integrated model of hydraulically redundant actuated shaking table is obtained. Then, a framework of Degree-of-Freedom (DoF) control for the shaking table of this type is put forward. To regulate forces among the redundant actuated systems and to reduce force couplings, an inner force balancing control method based on pseudo-inverse of Jacobian matrix is also employed. Simulation validated the proposed DoF control and inner force balancing method.
  • Hong Lianjin;Yang Desen;Shi Shengguo;Xing Shiwen
    . 2011, 30(3): 79-84.
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    In this thesis, a medium three dimensional co-oscillating vector hydrophone combined with pressure channels and vector channels is designed and accomplished based on requirement of the engineering in practice. The shape of the vector hydrophone is a cylinder with two calottes. The size is Ф44×88(mm), and the work frequency range is between 5Hz and 8kHz. Its performance is measured both in standing wave pipe and anechoic lab. The result of experimentation indicates that the pressure sensitivity of vector channels is -184dB(measure frequency: 1kHz, 0dB re 1V/μPa)with direction performance of cosine, and the pressure sensitivity of pressure channels is -198dB(0dB re 1V/μPa). The vector hydrophone has higher sensitivities, smaller volume, and be comfortable for hanging and constructing vector hydrophone array.
  • YANG Bin;Zhang Weidong;Wu Zhangmin;ZHANG Lixin
    . 2011, 30(3): 85-90,1.
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    On the basis of analysis for increasingly complex of services logic and functional requirements for the equipment remote monitoring and fault diagnosis system, a new system architecture based on SOA is proposed for the remote monitoring and diagnosis system in this paper. According to the design principles of SOA, different levels and different granularity of services logic and functional requirements for remote monitoring and diagnosis system is divided, and a loosely coupled web services system is built. The design and implement methods of core function models about the proposed architecture is given in this paper. Finally, a demo system is used to validate the feasibility of the proposed architecture.
  • LI Dong;SONG Tian-shu
    . 2011, 30(3): 91-95.
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    Based on the method of Green’s function, the problem of SH-wave scattering by a circular cavity near the interface in two well bonded piezoelectric materials was investigated in present paper. Firstly, coupled Green’s functions on out-plane elastic displacement and in-plane electric potential were constructed by using complex variable function, which were suitable for the problem of two semi-infinite piezoelectric materials and one of which had a circular cavity near the surface. Secondly, based on the method of conjunction and the continuity condition of the interface, the two semi-infinite media were bonded, while a series of Fredholm integral equations of first kind for the unknown stresses and electric field could be established so as to obtain the dynamic stress concentration factor and the electric field intensity concentration factor expressions around the circular cavity edge. Finally, some calculating examples were plotted to show the influence of the frequencies of incident wave, geometric parameters and piezoelectric characteristic parameters on dynamic stress concentration factor and electric field intensity concentration factor.
  • ZHANG Wei-zheng;YU Shu-rong;DING Xue-xing;Han ming-jun;DU Zhao-nian
    . 2011, 30(3): 96-99.
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    The angular wobbly of dry gas seal system has changed the micro-scale gap of moving and static rings and influenced the sealing performance, The dynamic model of the angular wobbly of the gas film and seal ring was established, and the gas film angular rigidity, critical moment of inertia and the two-dimensional angular wobbly vibration equation were solved by using the perturbation method and the Runge-Kutta method, then the seal structure stability parameters were obtained , and the vibratory response of best stability point and critical point were analyzed. The research results show that there are stability point-fields α=74°30′06″-75°16′10″ in the neighborhood of spiral angle α=75°,and the optimal value of the spiral angle α is 74°53′48″ in this example. The vibratory response of best stability point is quasi-periodic motion,but response of critical point is chaotic motion.
  • Tang Xue-Song
    . 2011, 30(3): 100-108.
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    Interaction between the macroscopic and microscopic factors and blunting effect of the crack tip during the crack dynamic propagation are investigated. A macroscopic crack moves with a constant speed under the in-plane tension. A microscopic V-notch tip is attached to the main crack by using a mesoscopic restraining stress transition zone so that a macro/micro dual scale moving crack model is thus developed. The problem is analytically solved in the framework of elastic dynamics and complex function theory and analytical solution is obtained. Two solutions under the macroscopic and microscopic scales are coupled by application of the continuity condition of crack opening displacement from macro to micro and the consistence condition of stress fields under two different scales. Two explicit equations to determine the mesoscopic and microscopic damage zone sizes are obtained. It is shown that the macroscopic stress field of a moving crack has a normal r1/2 singularity while comparatively, the microscopic stress field exhibits the weaker singularity due to the microscopic blunting effect of the crack tip. The crack moving speed can reach to the shear wave speed in the dual scale moving crack model. Therefore, the limitation that the crack moving speed can not exceed the Rayleigh wave speed in the classical moving crack theory can be removed. The numerical results show that the mesoscopic damage zone size, microscopic crack tip zone size and crack opening displacement depend on the crack moving speed, material property, restraining stress ratio and blunting angle of the crack tip etc.
  • SHEN Guo-hui;YU Guan-peng;SUN Bing-nan;LOU Wen-juan;LI Qing-xiang;YANG Shi-chao
    . 2011, 30(3): 109-114.
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    Wind tunnel tests were employed to study wind-induced interference effects on two adjacent cooling towers. The technique of adding roughness on model surface was applied to compensate for the Reynolds number effect due to model tests. Then the POD method was used to interpolate the wind pressures on the towers. After that, drag coefficients, lift coefficients and base shear coefficients on the isolated tower and two adjacent towers were calculated. Based on these coefficients, interference factors with respect to distances between two towers and wind azimuths were analyzed. Results show that, for the isolated tower, the mean drag coefficients are quite large whereas the mean lift coefficients are nearly zero. However, the mean-root-squares of drag coefficients and lift coefficients on the isolated tower are comparative in the magnitude. For two adjacent towers, the interference factors of mean and dynamic drag coefficients are almost the same. Most of the interference factors of dynamic lift coefficients are bigger than 1, while the biggest value reaches 1.75.

  • Zhou Tao;Zhu Ledong;Guo Zhenshan
    . 2011, 30(3): 115-118,.
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    The main content of this paper is to identify the aerodynamic parameters of Scanlan’s nonlinear empirical model using the data of vortex vertical response. Based on Hthe generalizedH harmonic Hwave functionH KBM method and using the HpresuppositionH of slowly varying parameters, the function of Scanlan’s nonlinear empirical model has been solved. And then the aerodynamic parameters of the model and the Scanlan’s nonlinear vortex-induced force are identified. After the Scanlan’s nParameters Identification of onlinear vortex-induced force is determined, the identification precision is evaluated via the following two methods: the response calculated according to the Newmarkmethod is compared with the field measured response; and compared with the self-excited VIV force which is extracted from the total force collected by the one-dimensional balances. The Experiment is carried in TJ-1 wind tunnel of Tongji University using the preliminarily designed section model of Xiangshangang Bridge. The vertical response of the section model was collected by the laser displacement sensor, and meanwhile the total force was collected by beam-type strain force balances of Hone-dimensionH.
  • Ai Jun;Qian Jiang;Yang Jie;Lu Yaoqing;Xu Chunlin
    . 2011, 30(3): 119-123.
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    This paper studies theoretically the dynamic characteristics of RC damage beams strengthened by prestressed CFRP sheets, and the relationship between frequency and pretension is derived. The author has test on the dynamic characteristics of RC beam strengthened by prestressed CFRP sheets; the primary frequency value is measured under different pretension. The author sets up the finite element model of good concrete beam in use of ANSYS software, and gets the reduction factor of elastic modulus of concrete by the optimization tools of ANSYS based on the analysis of damaged beam dynamic test; according to the primary frequency value of good beam strengthened by prestressed CFRP sheets, a linear fit to the formula of calculating the frequency is carried on, the author gets the factor of frequency and the formula for calculating primary frequency value of damaged beam. Lastly the theoretical value of primary frequency is compared with experimental values. At low prestress, the theoretical calculation results reflect the trend of experimental data; the results are in good agreement.
  • Wang Wen;Meng Guang;Liu Fang;You Mingyi
    . 2011, 30(3): 124-128.
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    Three groups of drop impact tests of solder joints have been conducted with different drop height. Proportional hazards model (PHM) is used to evaluate the effect of drop height on the solder joints’ life span. The mean-time-to failure (MTTF) and the failure probability density function (PDF) estimated from the PHM agree well with the experimental data, and this validates the effectiveness of the PHM. By the curve of the MTTF (with respect to different drop heights), it can be observed that the MTTF<10 when the drop height is greater than 0.6m, and this demonstrates that the lead-free solder joints are very sensitive to drop impact. Finally, the estimated lifetime of MTTF is integrated with the Miner’s law for cumulative damage model of lead-free solder joints.
  • Y.M. Chen;J.K. Liu;G. Meng
    . 2011, 30(3): 129-134.
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    Flutter is one of the main topics in aeroelasticity. Based on the nonlinear flutter model of a two-dimensional airfoil, several qualitative and/or quantitative methods for nonlinear flutter analysis are summarized. The qualitative methods included mainly refer to qualitative theories for ordinary differential equations. The quantitative methods are classified, for convenience only, as equivalent linearization method, describing function method, harmonic balance method, perturbation method and so on. Aiming at highlighting the relative merits of each type of methods, the mentioned techniques are briefly discussed and compared with each other.
  • HAN Zhi-Jun;WANG Jian-Jun;CUI Yan;LU Guo-Yun;ZHANG Shan-Yuan
    . 2011, 30(3): 135-138.
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    The chaotic motion of nonlinear elastic straight bar that has constitutive relation of the -shape during lonitudinal vibration are investigated.The dynamic equation of bar during lonitudinal vibration is changed into differential dynamic system by Galerkin principle.The conditions that the system has homoclinic orbit or heteroclinic orbit are given ,and the parameter equations of homoclinic orbit are solved. Using the Melnikov function ,the critical conditions that the system enters chaotic states are given. The regularity of chaotic motive region with and are obtained by numerical analysis, and the bifurcation diagrams,Displacement-time history diagram,Phase-plane diagram and Poincaré map show that the system occur steady motion or chaotic motion.The further research show that the quadric nonlinear item in constitutive relation has great effect on the dynamic behavior.
  • Zhang YuanYuan;Xu KeJun;Huang YunZhi;Chen JiaZhen;Ten Qin;Tan Jian
    . 2011, 30(3): 139-144.
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    Universal Exhaust Gas Oxygen (UEGO) Sensor can effectively provide the information of the oxygen content within wide air-fuel ratio scope. Due to its special structure, it cannot work normally without a controller. Therefore a robust PID algorithm is applied to the controller of UEGO sensor for controlling the value and direction of the pump cell voltage and exerting a feedback control action on the sensor. The pump cell current is detected and a nonlinear corrector for the pump cell current is designed, results of corrector is the excess air factor(λ). UEGO controller is implemented by means of dSPACE real time simulation system, and experiments are conducted on a carburetor engine. Experimental results show that the UEGO controller has strong robustness and good running performance. It can archive quick response and precision measurement whenλchanges in static and dynamic modes.
  • Lin Teng-jiao;Li Ying-chao;Yang Yan-ni
    . 2011, 30(3): 145-149.
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    Abstract: Considering of mesh deformation of gears, bending deformation of shafts and stiffness of beatings, the dynamic model of hypoid gear transmission was established with contact finite element method, and the support reaction of bearings was computed with LS-DYNA. Using the support reaction as input excitation, the dynamic model of hypoid gearbox was built and solved with ANSYS. Then compare the result of transient response analysis and that of experiment. At last taking the mean square root of vibration acceleration as the objective function, structure parameters of gearbox as design variables, the static stress, displacement and volume of housing as constraint condition, and sub-problem approximation method as solving method, the optimum design sets of housing can be obtained.
  • Lin Teng-jiao;Li Ying-chao;Yang Yan-ni
    . 2011, 30(3): 145-149,.
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    Abstract: Considering of mesh deformation of gears, bending deformation of shafts and stiffness of beatings, the dynamic model of hypoid gear transmission was established with contact finite element method, and the support reaction of bearings was computed with LS-DYNA. Using the support reaction as input excitation, the dynamic model of hypoid gearbox was built and solved with ANSYS. Then compare the result of transient response analysis and that of experiment. At last taking the mean square root of vibration acceleration as the objective function, structure parameters of gearbox as design variables, the static stress, displacement and volume of housing as constraint condition, and sub-problem approximation method as solving method, the optimum design sets of housing can be obtained.
  • Jun Tang;Tongqing Wang
    . 2011, 30(3): 150-154,.
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    This paper poses an active underwater broadband sound absorption method, in which a piece of PVDF piezocomposite smart material is used as the absorption material. A adaptive feedforward control system has been construct based on the filter-X LMS Algorithm. A kind of easy to implement in engineering method for secondary path modeling, based on the Delay-LMS algorithm, has been studied. The reference signal and error signal of the control system are received through separating the incident and the reflection sound pressure from out of the acoustic field using the digital time delay system. The experimental research of active duct noise control in the the pulse tube is accomplished. It is shown that the PVDF piezocomposite smart material can absorb almost all of the low frequency incident sound pressure with active control.
  • Duan Huming;;Shi Feng;Zhao Yongjie;Wang Honggang;Xie Fei
    . 2011, 30(3): 155-160.
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    reviewed that the research progresses of the measurement methods of road surface and road surface profile in recent years. A new high precision road surface profile measurement system is presented and its measurement principle and testing method are introduced. Based on the road surface profile measurement system, the measurement methods of road surface true profiles are discussed. These are many contrastive tests are completed with Level and Ruler in mountains, plains, cities and the areas of GPS signals are blocked. The contrastive tests got better results. In the end, the measurement methods of the road surface profiles are summarized, the using fields and merits and drawbacks of the road surface profile measurement system are evaluated.
  • Tang Jinyuan;Peng Fangjin
    . 2011, 30(3): 161-164,.
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    A finite element model, in which the influence of inertial load was concerned, was introduced for the dynamic meshing analysis of spiral bevel gears based on the theory of dynamics and Lagrange multiplier constraints. The influences of inertial load on the dynamic meshing characteristics were discussed. The result shows that the bigger the inertial load, the bigger the contact force. The inertial load also affects the width of the meshing zone, tooth contact stress and the location of the maximum contact stress. These validate that the inertial load must be taken into account in the dynamic contact analysis of spiral bevel gears.
  • LIU Changli;Li Cheng;ZHOU Shaoping;XIA Chunming
    . 2011, 30(3): 165-170.
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    The dynamic equations of the cracked rotor system were established using finite element method. Based on the approach of strain energy release rate, the stiffness matrix of the crack element was derived. The breathing behavior of the crack was represented by taking into account the opening and closing of the crack using stress intensity factor. The detailed researches were done on the characteristics of the breathing rules of transverse and slant cracks and the time-varying stiffness of the cracked element in a steady rotating period. The increase on the surface crack depth raises the variation of the stiffness of the cracked shaft. The characteristics of stiffness variation of the shaft with transverse or slant crack are not the same. Compared with the transverse crack, the slant crack will lead to more and greater coupled vibration. And the dynamic performance of the rotor will be more complicated.
  • LIU Hui-juan;LUO Yong-feng;Yang Lu-feng
    . 2011, 30(3): 171-176.
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    Unloading supporting system is important for semirigid structure, such as suspen-dome, during construction. Thus a failure criterion is presented for standard suspen-domes under unloading impact load. Using the criterion, analysis on the effect of unloading rate on the structure dynamic stability is developed adopting the Ansys software. The results that using direct unloading will be unsafe at some extent, improper unloading can cause structure failure are drawn. And further the structure failure mode and corresponding early warning system are obtained for unloading impact. Research for unloading failure mode and failure mechanism of a project case is presented, which verified the method obtained in the paper advisable and effective.

  • Lin song;Zhang kun;Sun Lei;Wang Xun;Liu Litiao;Li Tianyong
    . 2011, 30(3): 177-179,.
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    Experimental and constitutive study on dynamic characteristics of FS-2-80 rubber isolator were conducted. M-RT model to consider the influence of frequency and dynamic displacement amplitude was used to describe dynamic constitutive behavior of the isolator. The comparison between the experimental and predicted results showed that the model in the paper could preferably well describe the dynamic constitutive behavior. Based on the M-RT model, the relationship between dynamic stiffness, dynamic damping and amplitude, frequency was discovered. The nonlinear characteristics of FS-2-80 rubber isolator under small amplitude were also studied.
  • Wu Congxiao;Zhou Yun;Deng xuesong;Wu Congyong
    . 2011, 30(3): 180-184.
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    Based on the limited demand of inter-story drift and equivalent lateral rigidity ratio of high-level transfer story structure in Technical Specification for Concrete Structures of Tall Building and Code for seismic design of buildings, the calculation model that the high-level transfer story structure is decomposed to frame -shear wall structure below the transfer story and shear wall structure above the transfer story of equivalent lateral rigidity ratio has been adopted. Then, based on the above model, the mode-superposition response spectrum theory and calculation method of equivalent viscous damping ratio of structure with linear viscous dampers, the calculating formula of optimal damping coefficient of viscous damper of the high-level transfer story structure with viscous dampers is derived. Finally, a sample structure is studied utilizing the above method, analysis results indicate that the proposed formula is valid and the formula is simple and practical.
  • MA Meng;LIU Wei-ning;DING De-yun;Degrande G;LIU Wei-feng
    . 2011, 30(3): 185-190.
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    As a new subway route was planned to be close to a research building in Beijing, subway train-induced vibration will probably be effect to the sensitive instruments in future. To predict the vibration influence on these instruments after subway open to operation, environmental vibration on roadside and sensitive instrument tables were tested. The prediction method that combined field tests and numerical simulation was chosen, by which vibration attenuation or enlargement caused by structure and test tables in different frequencies can be taken into account. A coupled periodic FE-BE method was used to predict field dynamic response caused by subway trains, and the influence on sensitive instruments was predicted as well based on vibration transfer ratio which was calculated from environmental vibration data. Results show that,1) environmental vibration induced by road traffic is harmful to instrument and passive isolation measures on transverse direction should be taken; 2) with a low speed, subway train-induced vibration has little effect on instruments; 3) with a uniform speed over 60km/h, some measures for track vibration should be taken.
  • SHOU Xuan;XIA Tang-dai;
    . 2011, 30(3): 191-194.
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    The propagation of Rayleigh wave in a half space supporting a layer under the influence of gravity field was investigate, it was assumed that both the layer and the half-space are homogeneous, isotropic, elastic solids. Firstly, the dispersion equation of the Rayleigh wave under the influence of gravity field was obtained based on Biot’s theory of initial stress and the dynamical equations, and the dispersion equation was in agreement with the corresponding results when the gravity field was neglected. Then, the dispersion curves were obtained by means of numerical methods, and the influence of the Possion’s ratio and the thickness of the layer were analysed. The results indicate that the Possion’s ratio and the thickness of the layer have obvious effect on the dispersion curves.
  • Zhang Yu-min;Liu Jian-xin;Zhao Guo-hui
    . 2011, 30(3): 195-198,.
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    As an aseismatic measure of highway bridges, collapse-proof system is the method for seismic design and retrofitting, which consist of adequate seat length, seismic restrainers and unseating prevention devices. Unseating prevention devices are the ultimate security installment to prevent the girders form falling off the piers when bridge hit by earthquake, the effect of them are influenced by the design parameters. Based on the relational design standards at home and abroad, the seismic response of structures with different cable-unseating prevention devices, the pressure of unseating prevention devices and the effect of collapse-proof changed with cable length and design moving value were compared. The result show that the effect of collapse-proof decrease as the cable length and design moving value increase,the pressure of unseating prevention devices is larger than the design bearing capacity while the prarmeters are both smaller.
  • Ren Jie;Qing Wei;Ma Da-wei;Li Zhi-gang
    . 2011, 30(3): 199-204.
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    In this paper, the research of vehicle driving dynamics on a new multiple launch rocket system in vehicle for air defense was taken by appling the method of coupled rigid and flexible. Simulation of passing over vertical boss, horizonal trench and steep slope was included. The model of coupled rigid and flexible for vehicle and rocket launcher was established, and tires were considered in the model. The limited height of vertical boss and the limited width of horizonal trench were calculated, and the computing models of various limited road surface condition were developed. The driving dynamic simulation was performed. Simulation results of the dynamic response in the whole multiple launch rocket system were obtained. It can be used as a theoretical foundation for development and test of the new multiple launch rocket system in vehicle for air defense.
  • Yi Meng;Weijian Yi
    . 2011, 30(3): 205-210.
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    In order to research the dynamic behavior of concrete under low velocity impact, an experimental study was carried out on concrete cylinder specimens subjected to axial impact at strain rate of 100~101/s. Numerical simulations were also conducted with LS-DYNA by using continuous surface cap model (CSCM). The time-history curves of the impact load and the cylinder’s strain under various impact speeds and boundaries were measured. The failure process was captured by a high speed video camera. The test results show that: The peak load, the strain at peak load and the dynamic increase factor (DIF) increase with impact velocity but the impact force duration decrease with that. The curve of concrete average strength shows a shape of parabola with the impact velocity, and the relationship between the strain rate and the impact velocity is approximately linear. The simulation results show that the CSCM concrete constitutive model has a good precision in low-speed impact range, and the simulation failure modes also show a good consistency with the experimental results.
  • Wang Lixin;;YANG Zhao;Wang Haichao;Takayuki Obara;
    . 2011, 30(3): 211-214,.
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    In R.C. bridge pier, reinforcement arrangements of combined stirrups are complicated, which are difficult to construct, demand large quantity of rolled steel and hard to assure the quality of construction. According to these problems, a new type of reinforcement arrangement is proposed in this paper, called S-Clip. In order to validate the effect of this reinforcement, two groups of big sized piers were made, which are different from longitudinal reinforcement ratio. By the low cyclic reversed loading test, the seismic behavior is studied on the each bridge pier which uses conventional combined stirrups and S-Clip stirrups separately. The results indicate that the piers using new type reinforcement are not only take full advantage of material capability and have the same carrying capacity as the conventional one, but also have improved ductility. The application of this new type of reinforcement is in favor of improvement engineering quality. It speeds up the construction progress and economizes rolled steel. Therefore, the application of this technique has extensive prospect. It is very important for both the theory of structure and its development.
  • ZOU Tiefang;YU Zhi;CAI Ming;LIU Jike
    . 2011, 30(3): 215-219.
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    A car-pedestrian accident reconstruction method based on Pc-Crash was proposed. In this method, Pc-Crash is used as a simulation platform, the accident scene and the car-pedestrian multi-body model will be constructed firstly, and then accidents will be simulated according to contact positions of car-pedestrian and rest positions of car and pedestrian; after that, the rationality of simulation results will be validated by some other accident information, e.g., human body injury; finally, uncertainty of simulation results will be evaluated by uncertainty analysis methods. The steps of this method were given in a car-pedestrian accident case. In this case, all accident information was used reasonably, and the distribution of accident reconstruction result was obtained with the help of response surface method and Monte Carlo method. The case shows that reconstruction results from this method are more objective, and more efficient information for accident survey can obtained from these results.
  • Tu Fengchen;Chen Zhaobo;Liu Wangzhong;Fang Bo
    . 2011, 30(3): 220-224.
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    Assessment over performance of isolation in Whole-Satellite Vibration Isolation system is evaluated on the basis of such sets of indexes as transmission ratio of vibration、vibration level difference and power flow. However, it is inadequate to assess the isolation performance at the presence of sole transmissibility ratio from the bottom of isolator to the corresponding part at the top, while different limitations also exist in vibration level difference and power flow applied to evaluate practical system. A modified version as function of displacement admittance was proposed as a result of analysis of impact ratio of isolator. Then it was introduced to the evaluation of the self-designed newly Whole-Satellite Vibration Isolation platform. The results indicated that the proposed appraisal method had the advantage of featuring the isolation performance intuitive and simple in this system.
  • Li Xiukun;Li Tingting;Ma Tao
    . 2011, 30(3): 225-227.
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    The detection of targets in water based on geoacoustic measurement system has more superiority than conventional detection methods used in underwater acoustic engineering. But the geoacoustic signal usually interfered with strong low frequency disturbances. The EMD (empirical mode decomposition) method can separate the signal into different modes of vibration, and then the strong interference can be removed after the procedure. The use of EMD method to extract the signal from the strong trend of interference of geoacoustic signals is presented in this paper,and the standard of EMD decomposition component tendency is established. Proved by the results of actual geoacoustic signal, on the condition of keeping full characteristics of the signal, the EMD method can eliminate the complicated trend of interference precisely.
  • Zhang Bing;Sun Yong;Fan Qiang;Huang Zhenyu
    . 2011, 30(3): 228-233.
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    Thin and long structures like uniform beams and pipes are widely used in many engineering fields. These structures usually act as waveguides, conveying vibrational energy away from the source of excitation via wave propagation through the structure. Built-up beam or piping systems often comprise many joints or discontinuities in the form of flanges, hangers, supports, valves, pumps and changes in section. Dynamically, these discontinuities contribute stiffness, inertia and damping and can dramatically alter the response of the system. A robust technique for parametric joint identification would benefit many areas of dynamic modeling. Because of the complexity of discontinuities in practice, experiments are normally introduced to determine their dynamic parameters. Based on the wave propagation method, this paper presents a general analytical relationship between the dynamic parameters of a discontinuity and the reflection and transmission coefficients of the discontinuity. This relationship can be adopted to identify the dynamic parameters of the discontinuity by using the optimization curve-fit method. The case study, which involves an infinite uniform beam with a mass-like discontinuity formed by an attached steel block, is proposed to identify the dynamic parameters of the discontinuity through the wave reflection and transmission coefficients. The Monte Carlo simulation is applied to investigate the influence of the simulated measurement noise on the reflection coefficients. The experimental results show that the accuracy of the identified parameters has close relation with the identification frequency range and the errors of the identified mass and moment of inertia are within 5% and 15%, respectively.
  • Li Chunxiang;Zhang Fuhai;Gu Xinhua;Qing Liu
    . 2011, 30(3): 234-241.
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    Most designs of the passive, active, and semi-active control to structures are carried out based on their dynamic characteristics without consideration of the soil-structure interaction (SSI) effects. However, it is known that the intensive soil-structure interaction effects for structures built on soft soil give rise to the perturbations in their dynamic characteristics. These perturbations will significantly deteriorate the effectiveness of structural vibration control. Therefore, there is a need of quantitatively including the SSI into consideration in the design of structural vibration control. Firstly, an overview is rendered in the present article on the studies of the passive, active, and semi-active control for structures considering the SSI effects. Subsequently, a comprehensive survey is given on the earthquake vibration control for asymmetric buildings with consideration of the SSI. Then the future directions of semi-active control to asymmetric buildings are proposed taking the SSI into account. Finally, the support vector machine (SVM) based semi-active control is foreground on both the elastic and inelastic asymmetric buildings including the SSI effects into consideration.
  • YANG Ying-chun;ZHOU Qi-dou
    . 2011, 30(3): 242-245.
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    The boundary element method (BEM) was usually used to study the acoustic radiation in moving medium. A key issue of this method was how to calculate the weak integrals while the field point approaching the source point. A new integral method was developed to solve this problem. Using this method, the weak integral on the element surface was divided into singular integral and non-singular integral. For the singular part, analytic solution was obtained through rigorous mathematic derivation. As to the non-singular part, the integral was evaluated by numerical quadrature techniques. One of the major advantages of this method was that it could effectively compute the singular integrals with good accuracy.
  • WANG Xue-ren;MIAO Xu-hong;Jia Di;YE Wenrong
    . 2011, 30(3): 246-251.
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    One of the most obvious characteristics for the complex structures, such as ships, is that the vibration response is usually induced by multi-excitations, so study on the rules of that is valuable. A measurement technique for measuring vibration response of structures with multi-excitations was developed and applied to study the vibration characteristics of different cylindrical structures. The measurement results shows that effects of the phase difference on the vibration response and coupled relationship of excitations are obvious, and non linear response for some frequencies exist. When the excitations are non-correlated, the measurement results were compared with the predictions by FEM, which showed the validity of the measurement technique.
  • Huan Yi;Fang Qin;Liu Jin-chun;Chen Li;Du Mao-lin
    . 2011, 30(3): 252-257.
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    During 1995 Kobe earthquake, the metro stations suffered serious damage. The Daikai station was the first well-documented underground structure not crossing an active fault that has completely collapsed during an earthquake without liquefaction of the surrounding soil. Most columns of the Daikai metro station collapsed, including mid-column shear failure, which had never been observed in the past. In order to increase aseismic capability of metro stations, an analytical model of an elastically supported and damply supported beam (or column) subjected to combined action of seismic loading with static axial loading was developed. Based on the secondary Lagrange’s dynamic equations, an analytical method was established, which could be used to investigate the dynamic response of the beam. The effect of the axial loading on the dynamic responses of the member, the influences of the stiffness and damping coefficient were analyzed. In order to further investigate into the nonlinear response of an elastically supported and damply supported column, taking the Daikai metro station as an example, the 3D nonlinear responses of the column of the subway station with isolator supports subjected to the seismic loading in Kobe earthquake were analyzed by finite element software programme ABAQUS. The main conclusions can be drawn as follows: (1) The proposed analytical model of an elastically supported and damply supported beam (or column) can predict the dynamic response of the structural member subjected to action of combined seismic loading with static axial loading. (2) Setting isolators (springs and dampers) at the supports could reduce the deformation and damage of the column effectively, and hence the seismic-resistance of the structure could be also enhanced. (3) The axial static loading induced by the gravity of soil and structures provide the constraint on the column. But when the plastic hinge occurred at the joint between walls and slabs, the axial loading would accelerate the damage of the whole structure. Therefore, it could not be neglected in the structural dynamic analysis.
  • ZHONG Yan-chun;YANG Qing-jun;BAO Gang
    . 2011, 30(3): 258-263.
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    A nonlinear model of pneumatic vibration isolation system was established. Based on this,
    simulation analyses were done using matlab/simulink software and the response curves were got under simple
    harmonic excitation. The results show that the system has strong nonlinear characters. Simple harmonic excitation
    can induce subharmonic/multiple frequency and offset response at the zero frequency. When frequency near to the
    linearized natural frequency the subharmonic and multiple frequency become stronger. Guided by the simulation
    results, a possible numerical solution was put forward. This solution which based on harmonic balance method got
    the numerical solution by using iteration method. The validity of this method is verified through comparisons withsimulation results, which show good agreements with the numerical solution.

  • QU Cun;GAO Liang;XIN Tao;XU Liang
    . 2011, 30(3): 264-268.
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    The underground tunnel and cable in the city is complex, mass transit or inter-city high-speed railway would be built above the underground tunnel and cable. Beijing-Tianjin High-speed Railway was regarded as an example to research the dynamic influence which was applied by the vibratory load of high-speed train on the underground tunnel and cable. Using coupling dynamics, the vibration analysis model of vehicle-track coupling system was built, and the dynamic response of vehicle-track coupling system caused by the high-speed train was calculated. On the basis of finite element theory, the pile-slab-soil-tunnel longitudinal-transverse-vertical spatial coupled dynamic simulation model was built. The load spectrum, which was obtained by using the vibration analysis model of vehicle-track coupling system, was used as external motivation and acted on the dynamic simulation model, and the dynamic response of cable tunnel was researched. The results show that cable tunnel under pile-slab structure would not be influenced unfavorably by dynamic action of high-speed train vibratory load after the operation of Beijing-Tianjin High-speed Railway.

  • Ding Guobo;Xu Jinyu;Hu Zebin;Xi Feng;BAI Erlei
    . 2011, 30(3): 269-273.
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    The dynamic mechanic properties of early-strengthed polystyrene(EPS) concrete under 12 hours’, 24 hours’ and 36 hours’ maintenance duration were studied using split Hopkinson pressure bar(SHPB) apparatus. The corresponding stress-strain curves were gained, which was compared with the stress-strain curve of EPS concrete under 28 days’ maintenance duration. The results show that the dynamic compressive strengthes of EPS concrete under 36 hours’ and 28 days’ maintenance duration increase with the enhancing of strain rate, however the dynamic compressive strengthes of EPS concrete under 12 hours’ and 24 hours’ maintenance duration don’t increase obviously with the strain rate. Also the relation between dynamic compressive strength and average strain rate and influence of maintenance duration to dynamic compressive strength were researched. It is showed that the impact mechanics properties of EPS concrete increase with the enhancing of maintenance duration.
  • Lin Yaoxiong;
    . 2011, 30(3): 274-280.
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    Wave differential equation of prestressed box beam which has random cross-section was deduced. For the purpose of operating transmission and reflection coefficient matrix within segment with gradual change cross section on the prestressed beam, the segment was divided into several pieces of constant section beam. Transmission and reflection coefficient matrix of the amplitudes about the big end and the little end on the segment with non-uniform cross-section was operated based on the transfer matrix method from wave analysis on sandwich structure, and the matrix accuracy which was affected by the division number and cross-section dimension in the beam segment was analyzed by performing several subroutines programmed based on Maple software. The accuracy of method employed to operate transmission and reflection coefficient matrix within segment with gradual change cross section was verified using the solution of the wave differential equation according to the Galerkin method, combination of the first kind Bessel function was employed as trial function in the Galerkin method which was applied to solve the dynamic differential equation of the beam with gradual change cross-section. What is worth to be mentioned is that the trial function used in this paper can be used generally and more accurately to obtain the approximate solutions of differential equation of higher order which contained coefficients of series functions with the higher-order terms.