scholarly journals Analysis of the Vibration of the Ground Surface by Using the Layered Soil: Viscoelastic Euler Beam Model due to the Moving Load

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Hong-Yuan Huang ◽  
Ming-Jie Zhao ◽  
Yao Rong ◽  
Yang Sun ◽  
Xiao Xiao
Keyword(s):  
Moving Load ◽  
Ground Surface ◽  
Surface Displacement ◽  
Layered Soil ◽  
Beam Model ◽  
Moving Loads ◽  
Subway Tunnel ◽  
Euler Beam ◽  
Maximum Value ◽  
Viscoelastic Characteristics

Moving loads will have a certain impact on the safety of the structures. Since concrete is a viscoelastic material, the elastic concrete model cannot describe its viscoelastic characteristics under moving loads. It is necessary to establish a model that can describe the viscoelastic characteristics of concrete materials. In addition, the layered of the soil is also an important factor affecting the propagation of subway vibration waves. Considering the effects of the properties of the concrete material of the subway tunnel structure and the layered soil foundation as well as the load velocity on the vibration of the ground surface caused by the moving load, the standard linear elastic solid Euler beam model is described for the subway tunnel structure in this paper. The equivalent stiffness of the layered soil-viscoelastic beam coupling system subjected to a moving load is formed by using the transmission and reflection matrix (TRM) method. The numerical solution of ground surface displacement caused by subway tunnel in time-space domain is obtained by IFFT algorithm. The correctness of the algorithm is verified by comparing with the reference results. Numerical results show that, with the increase of the viscous coefficient of the viscoelastic Euler beam, the vibration amplitude of the ground surface will decrease. Up to a certain value of the increasing the viscous coefficient of the Euler beam, it will have little effect on the vibration amplitude of the ground surface. Therefore, the standard solid model of viscoelastic Euler beam can well describe the creep and relaxation of materials. The model of viscoelastic beam is reasonable for the working condition of subway tunnel concrete structure. At high speed of moving load, the maximum value of ground surface displacement spectrum will appear at the smaller frequency domain and the maximum value of displacement spectrum will also increase for the soft layer soil, while it is opposite to that of the stiffer layer soil.

scholarly journals Response Analysis of Ladder Beams Under Inertial Moving Load

2018 ◽  
Vol 23 (No 3, September 2018) ◽  
Author(s):  
Hongliang Li ◽  
Bo Zhang ◽  
Yunxuan Gong ◽  
Donghua Wang
Keyword(s):  
High Speed ◽  
Moving Load ◽  
Vibration Characteristics ◽  
Vibration Response ◽  
Response Analysis ◽  
Beam Model ◽  
Inertia Effect ◽  
Moving Loads ◽  
Model Free ◽  
Variable Section

With the continuous development of industry, variable-section beams and high speed moving loads with large mass are widely used. Thus, it is of great significance to study the vibration response of variable-section beam with the consideration of inertia effect. Most past research focuses on the vibration response on uniform beams considering inertial effects, but there is little research on the vibration response of moving loads on variable section beam considering the inertia effect. In this paper, a variable section beam is simplified as a multi-stage ladder beam. Using the Euler-Bernoulli beam model, free-vibration characteristics and forced vibration characteristics of cantilever ladder beam are analysed. Following this step the vibration response considering the influence of the inertia effect is studied and compared with the situation that does not consider the influence of inertia effect. The results show that the mass, velocity, and acceleration of moving loads influence the effect of inertia on the response. Mass is the main factor affecting the results. The inertia effect caused by the acceleration and velocity can be ignored when the mass of moving load is small. The results have good engineering applicability.

Dynamic Model of a Discrete-Pontoon Floating Bridge Subjected by Moving Loads

2010 ◽  
Vol 29-32 ◽  
pp. 732-737 ◽  
Author(s):  
Zhang Jun ◽  
Jun Liu ◽  
Xiao Lu Ni ◽  
Wei Li ◽  
Rong Mu
Keyword(s):  
Moving Load ◽  
Elastic Beam ◽  
Beam Model ◽  
Moving Loads ◽  
Concentrated Force ◽  
Vehicle Load ◽  
Comparison Results ◽  
Floating Bridge ◽  
Mass Spring ◽  
Damping Systems

A discrete-pontoon floating bridge is studied based on the beam model with assumption of the bridge deck as a elastic beam with uniform section, live load such as vehicle as moving concentrate forces, and pontoons as independent mass-spring-damping systems with singular degree of freedom. The comparison results of between vehicles and moving concentrated force show that a vehicle load can be simplified as one moving concentrated force. The present model can study not only a single moving load but also multiple moving loads.

Steady-State Vibrations of a Beam on a Pasternak Foundation for Moving Loads

1980 ◽  
Vol 47 (4) ◽  
pp. 879-883 ◽  
Author(s):  
H. Saito ◽  
T. Terasawa
Keyword(s):  
Steady State ◽  
Constant Velocity ◽  
Moving Load ◽  
Equations Of Motion ◽  
Pasternak Foundation ◽  
Moving Loads ◽  
Euler Beam ◽  
Exponential Fourier Transform ◽  
Steady State Solutions ◽  
Beam Theories

The response of an infinite beam supported by a Pasternak-type foundation and subjected to a moving load is investigated. It is assumed that the load is uniformly distributed over the finite length on a beam and moves with constant velocity. The equations of motion based on the two-dimensional elastic theory are applied to a beam. Steady-state solutions are determined by applying the exponential Fourier transform with respect to the coordinate system attached to the moving load. The results are compared with those obtained from the Timoshenko and the Bernoulli-Euler beam theories, and the differences between the displacement and stress curves obtained from the three theories are clarified.

scholarly journals Beam Theory of Thermal–Electro-Mechanical Coupling for Single-Wall Carbon Nanotubes

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 923
Author(s):  
Kun Huang ◽  
Ji Yao
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Beam Theory ◽  
Bending Stiffness ◽  
Single Wall Carbon Nanotubes ◽  
Beam Model ◽  
Euler Beam ◽  
New Model ◽  
Mechanical Coupling ◽  
Electrostatic Fields

The potential application field of single-walled carbon nanotubes (SWCNTs) is immense, due to their remarkable mechanical and electrical properties. However, their mechanical properties under combined physical fields have not attracted researchers’ attention. For the first time, the present paper proposes beam theory to model SWCNTs’ mechanical properties under combined temperature and electrostatic fields. Unlike the classical Bernoulli–Euler beam model, this new model has independent extensional stiffness and bending stiffness. Static bending, buckling, and nonlinear vibrations are investigated through the classical beam model and the new model. The results show that the classical beam model significantly underestimates the influence of temperature and electrostatic fields on the mechanical properties of SWCNTs because the model overestimates the bending stiffness. The results also suggest that it may be necessary to re-examine the accuracy of the classical beam model of SWCNTs.

The Calculation of the Supporting Stress of Track Plate in Ballastless High-Speed Rail Structure

2011 ◽  
Vol 97-98 ◽  
pp. 3-9
Author(s):  
Yang Wang ◽  
Quan Mei Gong ◽  
Mei Fang Li
Keyword(s):  
Stress Distribution ◽  
High Speed ◽  
Design Theory ◽  
Moving Load ◽  
Structure Design ◽  
Track Structure ◽  
Beam Model ◽  
High Speed Rail ◽  
Slab Track ◽  
Ballastless Track

The slab track is a new sort of track structure, which has been widely used in high-speed rail and special line for passenger. However, the ballastless track structure design theory is still not perfect and can not meet the requirements of current high-speed rail and passenger line ballastless track. In this paper, composite beam method is used to calculate the deflection of the track plate and in this way the vertical supporting stress distribution of the track plate can be gotten which set a basis for the follow-up study of the dynamic stress distribution in the subgrade. Slab track plate’s bearing stress under moving load is analyzed through Matlab program. By calculation and analysis, it is found that the deflection of track plate and the rail in the double-point-supported finite beam model refers to the rate of spring coefficient of the fastener and the mortar.The supporting stress of the rail plate is inversely proportional to the supporting stress of the rail. The two boundary conditions of that model ,namely, setting the end of the model in the seams of the track plate or not , have little effect on the results. We can use the supporting stress of the track plates on state 1to get the distribution of the supporting stress in the track plate when bogies pass. Also, when the dynamic load magnification factor is 1.2, the track plate supporting stress of CRST I & CRST II-plate non-ballasted structure is around 40kPa.

scholarly journals Dynamic Behavior of Tied-Arch Bridges under the Action of Moving Loads

2016 ◽  
Vol 2016 ◽  
pp. 1-17 ◽  
Author(s):  
Paolo Lonetti ◽  
Arturo Pascuzzo ◽  
Alessandro Davanzo
Keyword(s):  
Dynamic Behavior ◽  
Structural Characteristics ◽  
Moving Load ◽  
Sensitivity Analyses ◽  
Impact Factors ◽  
Moving Loads ◽  
Centripetal Acceleration ◽  
Design Variables ◽  
Dynamic Amplification ◽  
Arch Bridges

The dynamic behavior of tied-arch bridges under the action of moving load is investigated. The main aim of the paper is to quantify, numerically, dynamic amplification factors of typical kinematic and stress design variables by means of a parametric study developed in terms of the structural characteristics of the bridge and moving loads. The basic formulation is developed by using a finite element approach, in which refined schematization is adopted to analyze the interaction between the bridge structure and moving loads. Moreover, in order to evaluate, numerically, the influence of coupling effects between bridge deformations and moving loads, the analysis focuses attention on usually neglected nonstandard terms in the inertial forces concerning both centripetal acceleration and Coriolis acceleration. Sensitivity analyses are proposed in terms of dynamic impact factors, in which the effects produced by the external mass of the moving system on the dynamic bridge behavior are evaluated.

Analysis of Surface Subsidence Rule of the Shallow Subway Tunnel Construction

2013 ◽  
Vol 671-674 ◽  
pp. 1081-1086 ◽  
Author(s):  
Fei Fei Wang ◽  
Hui Ren Bai ◽  
Jing Jing Li
Keyword(s):  
Ground Surface ◽  
Calculation Model ◽  
Surface Subsidence ◽  
Surface Settlement ◽  
Tunnel Construction ◽  
Maximum Point ◽  
Subway Tunnel ◽  
Monitoring Frequency ◽  
Ground Surface Settlement ◽  
Value Range

In order to study the Dalian Metro section 202(Cujin Road station-Chunguang Street station, which is shallowly buried and covered with plain fill)’s ground surface settlement, the monitoring measuring station was built during the construction. After 3 months’ measuring by precision level,the data shows that the maximum point is in the center line of the tunnel of the upper part. The settlement is about 25.66-31.82mm. This paper put forward the concept of the distance span ratio β, β effective value range was - 4 <β< 4,Surface subsidence is closely related with β, Severe surface subsidence stage is -2 <β< 2, Occupy whole deformation is 67.5-77.6%,settlement rate about 0.84-0.93mm/d, so should strengthen the monitoring frequency, Suggest increases site tour. Field test results and the ground surface settlement calculation model winkle are identical with each other; the monitoring results have important guiding significance and reference for Dalian subway and the similar shallow depth excavation tunnel construction.

Study of ground surface displacement estimation using ALOS/PALSAR D-InSAR interferometry

2007 ◽  
Author(s):  
Atsushi Iwashita ◽  
Marina Kudo ◽  
Hisatoshi Baba ◽  
Toshikazu Morohoshi ◽  
Masanao Hara ◽  
...  
Keyword(s):  
Ground Surface ◽  
Surface Displacement ◽  
Alos Palsar ◽  
Displacement Estimation
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