• Title/Summary/Keyword: Moving Load analysis

Search Result 287, Processing Time 0.028 seconds

Dynamic Modeling and Experimental Validation for Escalators (에스컬레이터의 동적 모델링 및 실험적 검증)

  • Kang, Gyu-Woong;Kwon, Yi-Sug;Song, Seung-Bong;Hong, Seong-Wook
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2000.06a
    • /
    • pp.990-995
    • /
    • 2000
  • This paper presents a dynamic model for escalators to be used for the analysis and design of low vibration escalators. The dynamic model is developed so as to reflect the physical observation on peculiar characteristics such as the difference between up moving and down moving, and the resonance affected by the load applied. For validation of the dynamic model developed, experimental results are compared with numerical results from the model. The numerical study shows that the developed model is useful for analysis and design of escalator systems.

  • PDF

The Estimation of Structural-Borne Noise and Vibration of the Bridge under the Passage of the Light Rail Transit (경량전철 교량 상부구조의 열차주행에 대한 진동 및 소음 분석)

  • Yeo, In-Ho;Chung, Won-Seok;Kim, Sung-Choon;Kim, Sung-Il
    • Journal of the Korean Society for Railway
    • /
    • v.10 no.1 s.38
    • /
    • pp.22-28
    • /
    • 2007
  • During the passage of the train, the railway bridge undergoes vibration and noise. The noise of railway bridge can be occurred from various sources. The wheel-rail contact, noise from machinery parts, structural-borne noise, pantagraph noise and aerodynamic noise of the train work in combination. Running train is one of the most important factors for railway bridge vibration. The repeated forces with equidistant axles cause the magnification of dynamic responses which relates with maintenance of the track structure and structure-borne noises. The noise problem is one of the most important issues in services of light rail transit system which usually passes through towns. In the present study, The vibration and noise of the LRT bridge will be investigated with utilizing dynamics responses from moving train as input data for noise analysis.

Thermoelastic Finite Element Analysis of Multiple horizontal Subsurface Cracks Due to Sliding Surface Traction (마찰열을 고려한 미끄럼 접촉시 내부 복수 수평균열 전파해석)

  • 이진영;김석삼
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
    • /
    • 2000.11a
    • /
    • pp.50-58
    • /
    • 2000
  • A linear elastic fracture mechanics analysis of multiful subsurface cracks propagation in a half-space subjected to moving thermomechanical surface traction was peformed using the finite element method. The effect of frictional heat at the sliding surface on the crack growth behavior is analyzed in terms of the thermal load and peclet number. The crack propagation direction is predicted in light of the magnitudes of the maximum shear and tensile stress intensity factor ranges. When moving thermomechanical surface traction exists, subsurface horizontal cracks are propagation in-plane crack growth rate at the beginning but they are propagation out-of-plane crack growth rate by the frictional heat which is occurrence by the repeated sliding contact.

  • PDF

Research on Transition of Road Bed of Wuhan-Guangzhou Passenger Line and Bridge

  • Kang, Bo-Soon;Jun, Yang
    • International Journal of Railway
    • /
    • v.2 no.4
    • /
    • pp.180-186
    • /
    • 2009
  • High speed railway challenge the design, construction and maintaining of traditional railway, many traditional design concepts have been changed. Transition of railway and bridge has two main problems. one is that different lines have different ability of resisting distortion in area of trial load, which was known that problem of smooth transition of stiffness, the other is that differential settlement between artificial structure and earth structure cause bending of railway. The two problems have effect on train moving. The principle of processing transition of railway and bridge is same in world, but it is difficult to find relationship between design standard of transition, vehicle performance, line standard, design speed and so on form documentation and data reports. Based on mechanics, the paper analyzed dynamic performance of transition of high speed railway, studied various rough elements which is effective to train moving, built mathematical model of interaction of train and transition of high speed railway and developed numerical simulation software. In various different work conditions, we did great quantity of numerical simulation, comprehensive analysis and performance analysis.

  • PDF

Application of the exact spectral element method in the analysis of the smart functionally graded plate

  • Farhad Abad;Jafar Rouzegar;Saeid Lotfian
    • Steel and Composite Structures
    • /
    • v.47 no.2
    • /
    • pp.297-313
    • /
    • 2023
  • This study aims to extend the application of the spectral element method (SEM) to wave propagation and free vibration analysis of functionally graded (FG) plates integrated with thin piezoelectric layers, plates with tapered thickness and structure on elastic foundations. Also, the dynamic response of the smart FG plate under impact and moving loads is presented. In this paper, the dynamic stiffness matrix of the smart rectangular FG plate is determined by using the exact dynamic shape functions based on Mindlin plate assumptions. The low computational time and results' independence with the number of elements are two significant features of the SEM. Also, to prove the accuracy and efficiency of the SEM, results are compared with Abaqus simulations and those reported in references. Furthermore, the effects of boundary conditions, power-law index, piezoelectric layers thickness, and type of loading on the results are studied.

Appropriate Boundary Conditions for Three Dimensional Finite Element Implicit Dynamic Analysis of Flexible Pavement (연성포장의 3차원 유한요소해석을 위한 최적 경계조건 분석)

  • Yoo, Pyeong-Jun;Al-Qadi, Imad L.;Kim, Yeon-Bok
    • International Journal of Highway Engineering
    • /
    • v.10 no.4
    • /
    • pp.213-224
    • /
    • 2008
  • Flexible pavement responses to vehicular loading, such as critical stresses and strains, in each pavement layer, could be predicted by the multilayered elastic analysis. However, multilayered elastic theory suffers from major drawbacks including spatial dimension of a numerical model, material properties considered in the analysis, boundary conditions, and ill-presentation of tire-pavement contact shape and stresses. To overcome these shortcomings, three-dimensional finite element (3D FE) models are developed and numerical analyses are conducted to calculate pavement responses to moving load in this study. This paper introduces a methodology for an effective 3D FE to simulate flexible pavement structure. It also discusses the mesh development and boundary condition analysis. Sensitivity analyses of flexible pavement response to loading are conducted. The infinite boundary conditions and time-dependent history of calculated pavement responses are considered in the analysis. This study found that the outcome of 3D FE implicit dynamic analysis of flexible pavement that utilizes appropriate boundary conditions, continuous moving load, viscoelastic hot-mix asphalt model is comparable to field measurements.

  • PDF

Analysis and Countermeasure for Escalator Vibration (에스컬레이터 진동 분석 및 대책)

  • Lim, Su-Young;Kwon, Yi-Sug;Park, Seon-Ryong;Hong, Seong-Wook
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2000.06a
    • /
    • pp.984-989
    • /
    • 2000
  • This paper deals with an analysis and countermeasure of escalator vibration. The vibration characteristics of escalators are studied theoretically and experimentally to find the main cause of severe vibration. The main source of vibration in escalators is found to be chordal effect due to the step chain and sprocket system. It is also found that the vibration become significantly large at so called no load condition, in which the load due to passengers, during down-moving, is equal to the resistive force in the driving system. Dynamic absorbers are implemented to suppress the vibration. A theoretical analysis is made to determine the appropriate dynamic absorber. Theoretical and experimental study shows that dynamic absorber is effective to suppress the vibration in escalators.

  • PDF

Structural vibration in Escalators :(II) Analysis and Countermeasure (에스컬레이터의 구조적 진동 : (II) 분석 및 대책)

  • 임수영;권이석;박선용;홍성욱
    • Journal of KSNVE
    • /
    • v.10 no.5
    • /
    • pp.830-837
    • /
    • 2000
  • This paper deals with an analysis and countermeasure of escalator vibration. The vibration characteristics of escalators are studied theoretically and experimentally to fine the main cause of severe vibration. The main source of vibration in escalators is found to be chordal effect due to the step chain and sprocket system. It is also found that the vibration become significantly large at so called no load condition, in which the load due to passengers, during down-moving, is equal to the resistive force in the driving system. Dynamic absorbers are implemented to suppress the vibration, A theoretical analysis is made to determine the appropriate dynamic absorber. Theoretical and experimental study shows that dynamic absorber is effective to suppress the vibration in escalators.

  • PDF

Database Construction to Compute Representative Model of Load Power Factor in Bulk Power System (대규모 전력계통의 부하역률 대표모델 산정을 위한 데이터베이스 구축)

  • Cho, Jong-Man;Lee, Hyo-Sang;Lee, Jung-He;Kim, Jin-O
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
    • /
    • v.18 no.5
    • /
    • pp.83-89
    • /
    • 2004
  • The importance of the Load Power Factor(LPF) management is newly noticed from the voltage management and operation of the power system due to the rapidly increasing reactive power consumed. Therefore, this paper proposes the regional, seasonal and hourly Representative Model of Load Power Factor(RMLPF) considering load characteristics of all 154/22.9[kV] substations. The RMLPF is used to present a precision improvement of power system analysis and security. Computation of representative model of load utilizes the average flow method based on moving average method. The Energy Management System(EMS) data are used as the source to assess the load power factor.

Dynamic response of railway bridges traversed simultaneously by opposing moving trains

  • Rezvani, Mohammad Ali;Vesali, Farzad;Eghbali, Atefeh
    • Structural Engineering and Mechanics
    • /
    • v.46 no.5
    • /
    • pp.713-734
    • /
    • 2013
  • Bridges are vital components of the railroads. High speed of travel, the periodic and oscillatory nature of the loads and the comparable vehicle bridge weight ratio distinguish the railway bridges from the road bridges. The close proximity between estimations by some numerical methods and the measured data for the bridge-vehicle dynamic response under the moving load conditions has boosted the confidence in the numerical analyses. However, there is hardly any report regarding the responses of the railway bridges under the effect of the trains entering from the opposite directions while running at unequal speed and having dissimilar geometries. It is the purpose of this article to present an analytical method for the dynamic analysis of the railway bridges under the influence of two opposing series of moving loads. The bridge structural damping and many modes of vibrations are included. The concept of modal superposition is used to solve for the system motion equations. The method of solution is indeed a computer assisted analytical solution. It solves for the system motion equations and gives output in terms of the bridge deflection. Some case studies are also considered for the validation of the proposed method. Furthermore, the effects of varying some parameters such as the distance between the bogies, and the bogie wheelset distance are studied. Also, the conditions of resonance and cancellation in the dynamic response for a variety of vehicle-bridge specifications are investigated.