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vertical vibration of a large diameter pipe pile considering transverse inertia effect of pile

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Journal of Central South University 2016年第4期23卷 891-897页

作者：郑长杰刘汉龙丁选明周航 Key Laboratory of New Technology for Construction of Cities in Mountain Area (Chongqing University) Chongqing 400045 China

Considering the transverse inertia effect of pile, the vertical soil layer is studied. The wave propagations in the outer and inner soil dynamic response of a large diameter pipe pile in viscoelastic are simulated by three-dimensional elastodynamic theory and those in the pile are simulated by Rayleigh-Love rod theory. The vertical and radial displacements of the outer and inner soil are obtained by utilizing Laplace transform technique and differentiation on the governing equations of soils. Then, based on the continuous conditions between the pile and soils, the displacements of the pile are derived. The frequency domain velocity admittance and time domain velocity response of the pile top are also presented. The solution is compared to a classical rod model solution to verify the validity. The influences of the radii and Poisson ratio of pile on the transverse inertia effect of pile are analyzed. The parametric study shows that Poisson ratio and outer radius of pile have significant influence on the transverse inertia effect of large diameter pipe piles, while the inner radius has little effect.

关键词： large diameter pipe pile vertical vibration Rayleigh-Love rod transverse inertia effect

vertical vibration of Moving Strip in Rolling Process Based on Beam Theory

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Chinese Journal of Mechanical Engineering 2009年第5期22卷 680-687页

作者： SUN Jianliang PENG Yan LIU Hongmin JIANG Guangbiao Engineering Research Center of Rolling Equipment and Complete Technology of Ministry of Education Yanshan University Qinhuangdao 066004 China State Key Laboratory of Metastable Materials Science ＆ Technology Yanshan University Qinhuangdao 066004 China Hot Rolling Mill of Baoshan Iron and Steel Company Shanghai 200941 China

The shape and thickness qualities of strip are influenced by the vibration of rolling mill. At present, the researches on the vibration of rolling mill are mainly the vertical vibration and torsional vibration of single stand mill, the study on the vibration of tandem rolling mill is rare. For the vibration of tandem rolling mill, the key problem is the vibration of the moving strip between stands. In this paper, considering the dynamic of moving strip and rolling theory, the vertical vibration of moving strip in the rolling process was proposed. Take the moving strip between the two mills of tandem rolling mill in the rolling process as subject investigated, according to the theory of moving beam, the vertical vibration model of moving strip in the rolling process was established. The partial differential equation was discretized by Galerkin truncation method. The natural frequency and stability of the moving strip were investigated and the numerical simulation in time domain was made. Simulation results show that, the natural frequency was strongly influenced by the rolling velocity and tension. With increasing of the rolling velocity, the first three natural frequencies decrease, the fourth natural frequency increases; with increasing of the unit tension, when the rolling velocity is high and low, respectively, the low order dimensionless natural frequency gradually decreases and increases, respectively. According to the stability of moving strip, the critical speed was determined, and the matching relationship of the tension and rolling velocity was also determined. This model can be used to study the stability of moving strip, improve the quality of strip and develop new rolling technology from the aspect of dynamics.

关键词： moving strip vertical vibration galerkin truncation method stability

Structural relaxation and avalanche dynamics of particle piles under vertical vibration

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Particuology 2022年第9期20卷 65-74页

作者： Lizhuo Zhu Haifeng Lu Xiaolei Guo Haifeng Liu Shanghai Engineering Research Center of Coal Gasifiication East China University of Science and TechnologyShanghai 200237China

Granular matter can exhibit solid or liquid behavior,which contains complex physical *** this work,we experimentally investigated the structural relaxation and avalanche dynamics of particle piles under vertical *** influence of vibration parameters on the avalanche process was *** morphological features of avalanches were recorded and classified using high-speed *** effects of vibration parameters and particle properties on the relaxation mode are *** is found that the evolution of particle pile height with time can be described by an exponential decay *** relaxation rate and avalanche characteristics of four types of particles with different sizes are *** the same acceleration level,for two larger particles,a smaller amplitude(A=0.025 mm)leads to a faster relaxation rate,while for two smaller particles,a large amplitude(A=0.500 mm)leads to a faster relaxation *** analogy powder surface tension is introduced to address the cohesion and flowability evolution of particles under vibration.

关键词： Particle pile vertical vibration Avalanche Flowability

Fuel efficient model predictive control strategies for a group of connected vehicles incorporating vertical vibration

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Science China(Technological Sciences) 2017年第11期60卷 1732-1746页

作者： QIAN LiJun QIU LiHong CHEN Peng ABDOLLAHI Zoleikha PISU Pierluigi Department of Vehicle Engineering Hefei University of Technology International Center for Automotive Research Clemson University

This paper presents a decentralized fuel efficient model predictive control(MPC) strategy for a group of connected vehicles incorporating vertical vibration. To capture the vehicle vibration dynamics, the dynamics of the suspension system is integrated with the longitudinal dynamics of the vehicle. Furthermore, a MPC framework with finite time horizon is formulated to calculate the optimal velocity profile that compromises fuel economy, mobility and ride comfort for every individual vehicle with the safety and physical constraints considered. In the MPC framework, the target velocity is calculated using signal phase and timing(SPAT)information to reduce the number of stoppage at red lights, and the vertical acceleration is calculated parallel to the calculation of the fuel consumption. The MPC optimal problem is solved with fast-MPC approach which enhances the computational efficiency via exploiting the structure of the control system and approximate methods. Simulation studies are conducted over different SPATs and connectivity penetration rates and the results validate the advantages of the proposed control architecture.

关键词： model predictive control connected vehicles fuel economy vertical vibration intelligent transportation system

Axisymmetrical analytical solution for vertical vibration of end-bearing pile in saturated viscoelastic soil layer

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Applied Mathematics and Mechanics(English Edition) 2010年第2期31卷 193-204页

作者：杨骁潘元 Department of Civil Engineering Shanghai University

Based on elasticity and the theory of saturated porous media, and regarding the pile and the soil as a single phase elastic and a saturated viscoelastic media, respectively, the dynamical behavior of vertical vibration of an end-bearing pile in a saturated viscoelastic soil layer is investigated in the frequency domain using the Helmholtz decomposition and variable separation method. The axisymmetrical analytical solutions for vertical vibrations of the pile in a saturated viscoelastic soil layer are obtained, and the analytical expression of the dynamical complex stiffness of the pile top is presented. Responses of dynamic stiffness factor and equivalent damping of pile top with respect to the frequency are shown in figures using a numerical method. Effects of the saturated soil parameters, modulus ratio of the pile to soil, slenderness ratio of pile and pile＇s Poisson ratio, etc. on the stiffness factor and damping are examined. It is shown that, due to the effect of the transversal deformation of the pile and the radial force of the saturated viscoelastic soil acting on the pile, the dynamic stiffness factor and the damping derived from the axisymmetrical solution are greatly different from those derived from the classical Euler-Bernoulli rod model, especially at some specific excitation frequencies. Therefore, there are limitations on applicability of the Euler-Bernoulli rod model in analyzing verticai vibration of the pile. More accurate analysis should be based on a three-dimensional model.

关键词： saturated porous medium pile-soil dynamical interaction axisymmetricalanalytical solution vertical vibration parameter study

vertical vibrations of elastic foundation resting on saturated half-space

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Applied Mathematics and Mechanics(English Edition) 2007年第9期28卷 1199-1207页

作者：王国才王哲孟凡丽 School of Civil Engineering and Architecture Zhejiang University of Technology

This paper is mainly concerned with the dynamic response of an elastic foundation of finite height bounded to the surface of a saturated half-space. The foundation is subjected to time-harmonic vertical loadings. First, the transform solutions for the governing equations of the saturated media are obtained. Then, based on the assumption that the contact between the foundation and the half-space is fully relaxed and the halfspace is completely pervious or impervious, this dynamic mixed boundary-value problem can lead to dual integral equations, which can be further reduced to the Predhohn integral equations of the second kind and solved by numerical procedures. In the numerical extortples, the dynamic colnpliances, displacements and pore pressure are developed for a wide range of frequencies and material/geometrical properties of the saturated soil-foundation system. In most of the cases, the dynamic behavior of an elastic foundation resting on the saturated media significantly differs from that of a rigid disc on the saturated half-space. The solutions obtained can be used to study a variety of wave propagation problems and dynamic soil-structure interactions.

关键词： saturated media elastic foundation vertical vibration dynamic colnplialice dual integral equations

Analytical model of vertical vibrations in piles for different tip boundary conditions:parametric study and applications

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2013年第2期14卷 79-93页

作者： Ning WANG Kui-hua WANG Wen-bing WU MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering Department of Civil EngineeringZhejiang University Engineering Faculty China University of Geoscience

In this paper,a model named fictitious soil pile was introduced to solve the boundary coupled problem at the pile *** the model,the soil column between pile tip and bedrock was treated as a fictitious pile,which has the same properties as the local *** tip of the fictitious soil pile was assumed to rest on a rigid rock and no tip movement was *** combination with the plane strain theory,the analytical solutions of vertical vibration response of piles in a frequency domain and the corresponding semi-analytical solutions in a time domain were obtained using the Laplace transforms and inverse Fourier transforms.A parametric study of pile response at the pile tip and head showed that the thickness and layering of the stratum between pile tip and bedrock have a significant influence on the complex ***,two applications of the analytical model were *** is to identify the defects of the pile shaft,in which the proposed model was proved to be accurate to identify the location as well as the length of pile *** application of the model is to identify the sediment thickness under the pile *** results showed that the sediment can lead to the decrease of the pile stiffness and increase of the damping,especially when the pile is under a low frequency load.

关键词： Soil-pile interaction Complex impedance Pile tip vertical vibration Sediment

Development of design charts to predict the dynamic response of pile supported machine foundations

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Frontiers of Structural and Civil Engineering 2024年第4期18卷 663-679页

作者： Deepthi SUDHI Sanjit BISWAS Bappaditya MANNA Department of Civil Engineering National Institute TechnologyWarangal 506004India Department of Civil Engineering Indian Institute of TechnologyDelhi 110016India

This paper proposes design charts for estimating imperative input parameters for continuum approach analysis of the nonlinear dynamic response of *** and analytical studies using continuum approach have been conducted on single and 2×2 grouped piles under coupled and vertical modes of vibration,for different dynamic forces and pile *** these design charts are derived from model piles,the charts have been validated for prototype pile foundations using scaling *** experimental responses of model piles are scaled up and these responses exhibit good agreement with analytical *** study also extends to estimation of the errors in computing frequency–amplitude responses with an increase in pile *** is found that,with an increase in pile length,the errors also *** effectiveness of the proposed design charts is also checked with data based on different field setups given in existing literature,and these charts are found to be ***,the developed design charts can be beneficial in estimating the input parameters for continuum approach analysis for determining the nonlinear responses of pile supported machine foundations.

关键词： pile foundation vertical vibration coupled vibration continuum approach soil-pile separation boundary zone parameters

Experimental study and analysis on the rising motion of grains in a vertically-vibrated pipe

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Chinese Physics B 2015年第3期24卷 224-229页

作者：刘煜赵俊红 Electric Power Research Institute Henan Electric Power Company Luoyang College Civil Aviation Flight University of China

Previous experimental investigations have shown that when a narrow pipe is inserted into a granular bed and is vibrated vertically but the granular bed is kept still, the grains in the bed can enter the pipe and rise against gravity along the pipe and finally stabilized at a certain height. The growth velocity and final stable height of the grain column inside the pipe can be controlled by varying the vibration conditions. In this paper, we discuss those experimental findings. We establish a mathematic relation between the grain column height（h） and time（t）, and by using the relation we discuss the change of the growth velocity（ dh/ dt） and acceleration（ d^2h/ dt^2） with t and h, respectively. We also analyze the mechanism of the rising motion of the grains during vibration. Furthermore, we derive a theoretical expression for describing the final stable height（h st）, which shows that the main factors influencing the height are vibration strength（Γ）, bulk density of grains,inner diameter of the pipe, and vibration frequency, and that h st increases nonlinearly in the presence of air and linearly in a vacuum environment with increasing Γ.

关键词： granular matter vertical vibration theoretical analysis