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Life Prediction Based on transient dynamics Analysis of Van Semi-trailer with Air Suspension System

Chinese Journal of Mechanical Engineering 2011年第3期24卷 372-379页

作者： LI Liang SONG Jian HE Lin ZHANG Mengjun LI Hongzhi State Key Laboratory of Automotive Safety and Energy Tsinghua University Beijing 100084 China

The early fatigue damage in the van-body of the semi-trailer is often caused by the unique mechanical characteristics and the dynamic impact of the *** traditional finite element method with static strength analysis cannot support the fatigue design of van-body;thus,the dynamics analysis should be adopted for the endurance *** accurate dynamics model to describe the transient impacts of all kinds of uneven road and the proper system transfer functions to calculate the load transfer effects from tire to van-body are two critical factors for transient dynamics *** order to evaluate the dynamic performance,the dynamics model of the trailer with the air suspension is brought *** the analysis method of the power spectral density （PSD） is set up to study the transient responses of the road dynamic *** transient responses transferred from axles to van-body are calculated,such as dynamic stress,dynamic RMS acceleration,and dynamic load *** on the above dynamic responses,the fatigue life of van-body is predicted with the finite element analysis （FEA） *** the test parameters of the trailer with air suspension,the simulation system with Matlab/Simulink is constructed to describe the dynamic responses of the impacts of the tested PSD of the vehicle axles,and then the fatigue life is predicted with FEA *** simulated results show that the vibration level of the van-body with air suspension is reduced and the fatigue life is *** real vehicle tests on different roads are carried out,and the test results validate the accuracy of the simulation *** proposed fatigue life prediction method is effective for the virtual design of auto-body.

关键词： van-body air suspension system transient dynamics power spectral density (PSD) life prediction

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Complex transient dynamics of hidden attractors in a simple 4D system

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Chinese Physics B 2015年第5期24卷 270-274页

作者：党小宇李春彪包伯成武花干 College of Electronic and Information Engineering Nanjing University of Aeronautics and Astronautics School of Electronic & Information Engineering Nanjing University of Information Science & Technology School of Information Science and Engineering Changzhou University School of Electronic and Optical Engineering Nanjing University of Science and Technology

A simple four-dimensional system with only one control parameter is proposed in this paper. The novel system has a line or no equilibrium for the global control parameter and exhibits complex transient transition behaviors of hyperchaotic attractors, periodic orbits, and unstable sinks. Especially, for the nonzero-valued control parameter, there exists no equilibrium in the proposed system, leading to the formation of various hidden attractors with complex transient dynamics. The research results indicate that the dynamics of the system shows weak chaotic robustness and depends greatly on the initial states.

关键词： transient dynamics hidden attractor equilibrium

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Stability and dispersion analysis of reproducing kernel collocation method for transient dynamics

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Applied Mathematics and Mechanics(English Edition) 2011年第6期32卷 777-788页

作者：罗汉中刘学文黄醒春 School of Naval Architecture Ocean and Civil EngineeringShanghai Jiao Tong University Siemens Industry Software (China) Co. Ltd.

A reproducing kernel collocation method based on strong formulation is introduced for transient dynamics. To study the stability property of this method, an algorithm based on the von Neumann hypothesis is proposed to predict the critical time step. A numerical test is conducted to validate the algorithm. The numerical critical time step and the predicted critical time step are in good agreement. The results are compared with those obtained based on the radial basis collocation method, and they axe in good agreement. Several important conclusions for choosing a proper support size of the reproducing kernel shape function are given to improve the stability condition.

关键词： reproducing kernel collocation method (RKCM) stability analysis disper-sion analysis transient dynamics

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Invariant and energy analysis of an axially retracting beam

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Chinese Journal of Aeronautics 2016年第4期29卷 952-961页

作者： Yang Xiaodong Liu Ming Zhang Wei Roderick V.N.Melnik Beijing Key Laboratory of Nonlinear Vibrations and Strength of Mechanical Engineering College of Mechanical Engineering Beijing University of Technology M2NeT Laboratory The MS2Discovery Interdisciplinary Research Institute Wilfrid Laurier University

The mechanism of a retracting cantilevered beam has been investigated by the invariant and energy-based analysis. The time-varying parameter partial differential equation governing the transverse vibrations of a beam with retracting motion is derived based on the momentum theorem. The assumed-mode method is used to truncate the governing partial differential equation into a set of ordinary differential equations (ODEs) with time-dependent coefficients. It is found that if the order of truncation is not less than the order of the initial conditions, the assumed-mode method can yield accurate results. The energy transfers among assumed modes are discussed during retraction. The total energy varying with time has been investigated by numerical and analytical methods, and the results have good agreement with each other. For the transverse vibrations of the axially retracting beam, the adiabatic invariant is derived by both the averaging method and the Bessel function method. (C) 2016 Chinese Society of Aeronautics and Astronautics. Production and hosting by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.

关键词： Adiabatic invariants Asymptotic analysis Retracting beam Time-varying systems transient dynamics

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dynamics of Primary Events in the Photocycle of Excited Bacteriorhodopsin

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Acta Biochimica et Biophysica Sinica 2004年第11期36卷 724-728页

作者： Jun-Jun LU, Ming MING, Yi YANG, Jia WU, Bo LI, Jian-Dong DING, Qing-Guo LI, and Shi-Xiong QIANDepartment of Physics, Fudan University, Shanghai 200433, China Department of Macromolecular Science, Key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai 200433, China Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200433, China Department of Physics Fudan UniversityShanghai 200433 China Department of Macromolecular Science Key Laboratory of Molecular Engineering of Polymers Fudan UniversityShanghai 200433 China Department of Physiology and Biophysics School of Life Sciences Fudan UniversityShanghai 200433 China

transient dynamic behavior of the excited bacteriorhodopsin (BR), which was isolated from the strain H. salinarum, was studied at excitation wavelength from 585 to 639 nm. With the one-color femtosecond (fs) pump-probe technique, we revealed the primary events in BR's photocycle that took place in an ultrafast time scale. From the analysis of the decay components of the dynamical traces, it was evident that the isomerization of the retinal

关键词： bacteriorhodopsin transient dynamics primary events femtosecond laser pump-probe technique

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Dynamic Response of Foundations during Startup of High-Frequency Tunnel Equipment

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Computer Modeling in Engineering & Sciences 2024年第7期140卷 821-844页

作者： Dawei Ruan Mingwei Hu College of Civil and Transportation Engineering Shenzhen UniversityShenzhen518060China State Key Laboratory of Intelligent Geotechnics and Tunnelling Shenzhen UniversityShenzhen518060China Key Laboratory of Coastal Urban Resilient Infrastructures of Ministry of Education Shenzhen UniversityShenzhen518060China Underground Polis Academy Shenzhen UniversityShenzhen518060China Shenzhen Key Laboratory of Green Efficient and Intelligent Construction of Underground Metro StationShenzhen UniversityShenzhen518060China

The specialized equipment utilized in long-line tunnel engineering is evolving towards large-scale,multifunctional,and complex *** vibration caused by the high-frequency units during regular operation is supported by the foundation of the units,and the magnitude of vibration and the operating frequency fluctuate in different engineering contexts,leading to variations in the dynamic response of the *** high-frequency units yield significantly diverse outcomes under different startup conditions and times,resulting in failure to meet operational requirements,influencing the normal function of the tunnel,and causing harm to the foundation structure,personnel,and property in severe *** article formulates a finite element numerical computation model for solid elements using three-dimensional elastic body theory and integrates field measurements to substantiate and ascertain the crucial parameter configurations of the finite element *** proposing a comprehensive startup timing function for high-frequency dynamic machines under different startup conditions,simulating the frequency andmagnitude variations during the startup process,and suggesting functions for changes in frequency and magnitude,a simulated startup schedule function for high-frequency machines is created through *** into account the selection of the transient dynamic analysis step length,the dynamic response results for the lower dynamic foundation during its fundamental frequency crossing process are *** validation checks if the structural magnitude surpasses the safety threshold during the critical phase of unit startup traversing the structural resonance *** design recommendations for high-frequency units’dynamic foundations are provided,taking into account the startup process of the machine and ensuring the safe operation of the tunnel.

关键词： Tunnel equipment high-frequency units startup conditions transient dynamics dynamic response foundation design

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The maximum amplification of perturbations in ecological systems

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International Journal of Biomathematics 2017年第1期10卷 153-173页

作者： Hailing Wang Jicheng Zhang Xiao-SongYang Key Laboratory of Biologic Resources Protection andUtilization of Hubei Province Hubei University for Nationalities Enshi 445000 P. R. China School of Science Hubei University for Nationalities Enshi 445000 P. R. China School of Medical Hubei University for Nationalities Enshi 445000 P. R. China Program for Ecology and Environment Science School of Mathematics and StatisticsHuazhong University of Science and Technology Wuhan 430074 P. R. China

Conventionally, most researches of ecologicM models focus mainly on the asymptotic stability properties near equilibria. However, transient effects can be important. It dom- inates the dynamics seen in experimental or field studies. transient behavior near an equilibrium is measured by resilience, reactivity, the maximum amplification of a per- turbation and the time at which the maximum amplification occurs. In this paper, we demonstrate emphatically the calculation of the amplification envelope of a homoge- neous system of linear equations, then apply it to three ecological models. We conclude that transient amplification of perturbations to a stable equilibrium should be a very common ecological phenomenon, and reactive systems have huge changes around their equilibria.

关键词： transient dynamics perturbation reactivity amplification envelope ecolo-gical models.

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Extreme parameter sensitivity of transient persistence in spatially coupled ecological systems

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Theoretical & Applied Mechanics Letters 2011年第6期1卷 51-56页

作者： Lin Du, Wei Xu,) and Zhanguo Li Department of Applied Mathematics, Northwestern Polytechnical University, Xi’an 710072, China Department of Applied Mathematics Northwestern Polytechnical University Xi'an 710072 China

This paper investigates persistence of transient dynamics depending on parameters in spatially coupled ecological systems. We emphasis that the persistence time can be obtained by populations of species or Lyapunov exponents of transient dynamics. It is found that extreme sensitive dependence of persistence on parameters occurs commonly in ecological models. A non-zero uncertainty exponent is used to characterize the high sensitivity in a reasonable parameter region. The result of a small uncertainty exponent indicates a fractal structure of transient persistence in the two-dimensional parameter space. In spite of different methods of measurement, the fractal dimensions have a good consistency. Since populations of natural communities with many coupled oscillators are often affected by disturbance of migration rates, the large probability of error in estimating persistence of transients should be concerned.

关键词： transient dynamics predator-prey systems persistence sensitivity uncertainty exponents fractal dimensions

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Low Velocity Impact Response on GFRP and GF-SMP Panels in Structural and High Frequency Bands

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Advances in Aerospace Science and Technology 2020年第2期5卷 58-70页

作者： R. Basavanna S. Raja Karisiddappa Civil Engineering Department Visvesvaraya Technological University Belagavi India Structural Technological Division CSIR-National Aerospace Laboratories Bangalore India Visvesvaraya Technological University Belagavi India

A low velocity impact response study has been carried out on glass fibre composite laminates, made up of regular aircraft grade epoxy (GFRP) and shape memory polymer (GF-SMP). Under various impact loading intensities (4J, 6J, 12J), the responses are measured by a network of PZT (Lead Zirconate Titanate) sensors. A signal analysis methodology is subsequently developed to process the very high frequency (60 MHz) sampled data. In two frequency bands, namely 0 - 2000 Hz and 0 - 100 KHz, the results are examined and the transient dynamic behaviours of the composite laminates are evaluated. It is observed that both the laminates have generated the high frequency structural waves (0 - 100 KHz), which can be exploited to examine the BVID. However, GF-SMP laminate has shown some advantage in terms of energy dissipation in the structural frequency band (<2000 Hz). Further, the GF-SMP laminate has demonstrated its capability to generate very high frequency structural waves, which could carry the damage information like BVID due to impact event to nearby sensors for impact event monitoring and health assessment.

关键词： Impact Low Velocity PZT Patches GFRP Composite Laminate transient dynamics

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