Research on new material scale model technology of rail transit vehicles based on similarity theory

2021 ◽  
Author(s):  
Yubo Wang
Keyword(s):  
Similarity Theory ◽  
Scale Model ◽  
Rail Transit ◽  
New Material

Experimental Study on Non-Perpendicular Frame Structure of Tall Building

2008 ◽  
Vol 400-402 ◽  
pp. 593-598
Author(s):  
Wei Xing Shi ◽  
Cheng Qing Liu ◽  
Xi Lin Lu ◽  
Song Zhang ◽  
Ying Zhou
Keyword(s):  
Similarity Theory ◽  
Structural Type ◽  
Shaking Table ◽  
Frame Structure ◽  
Scale Model ◽  
Prototype Structure ◽  
Table Model ◽  
Practical Engineering ◽  
Whiplash Effect ◽  
Shaking Table Model Test

A shaking table model test is conducted for Guangzhou West Tower to study its seismic behavior in State Key Laboratory for Disaster Reduction in Civil Engineering at Tongji University. Guangzhou West Tower adopts a new structure system and the significant characteristic of this system is the non-perpendicular frame arranged around the building, acting both as columns and bracings. Based on the similarity theory and member equivalent principle，a 1/80 scale model of this building is made of polymethyl methacrylate(PMMA). The model’s dynamic characteristics, earthquake-resistant behavior, responses of acceleration and deformation under different wave peak values are investigated, then the seismic responses of the prototype structure are deduced and analyzed. The whiplash effect of the prototype structure is studied, and the weak position of the structure is found out. The experiment results demonstrate that it is feasible to apply this structural type to practical engineering. Finally, some suggestions for the engineering design of the prototype structure are put forward.

A study of modeling experiments of the vibration behavior of elevated railway box girder

2018 ◽  
Vol 25 (5) ◽  
pp. 984-995 ◽  
Author(s):  
Kun Luo ◽  
Xiaoyan Lei
Keyword(s):  
High Speed ◽  
Similarity Theory ◽  
Longitudinal Direction ◽  
Calculation Model ◽  
Scale Model ◽  
Box Girder ◽  
Vibration Transmissibility ◽  
Girder Bridge ◽  
Structure Simplification ◽  
Model Similarity

Based on the model similarity theory, this article deduces the model similarity relationship of the elevated railway box girder at the elastic stage and designs a 1/10 box girder scale model by adopting a 32 m simply-supported box girder bridge from the Beijing–Shanghai Railway as the prototype. It then verifies the validity of the model design and the dynamic similarity between the 1/10 model and the prototype through constraint mode and free mode experiments on the 1/10 scale model, together with transient finite element calculation. The dynamic calculation model is utilized here for the analysis of the errors occurring in the production of the model, and the effect of the model structure simplification on the box girder mode frequency and vibration response. Finally, the article studies the vibration transmissibility characteristics between the plates and along the longitudinal direction by means of model testing. It also discusses the effect of different bridge support stiffness on the box girder vibration. The results presented in this paper can provide a method for forecasting and evaluating the existing or plan-to-build high speed railway environment vibration.

scholarly journals Similarity Analysis between Scale Model and Prototype of Large Vibrating Screen

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Zerong Zhang ◽  
Yongyan Wang ◽  
Zhimin Fan
Keyword(s):  
Frequency Response ◽  
Natural Frequencies ◽  
Similarity Theory ◽  
Similarity Criteria ◽  
Scale Model ◽  
Mode Shapes ◽  
Dynamic Stresses ◽  
Operating Condition ◽  
Vibrating Screen ◽  
Scale Down

In order to predict the physical characteristics of the large vibrating screen from its scale-down model, the similarity ratios of the frequency response functions, mode shapes, and dynamic stresses between the prototype and the scale model screen are built according to the similarity theory. The natural frequencies and modal shapes are extracted from the frequency response function by means of modal tests, in which the relative error of the natural frequencies is less than 9% and the modal shapes are consistent between the prototype and the model. The operating condition parameters including dynamic stress, displacement, velocity, and acceleration were also measured and conform to the similarity criteria. The results show that the inherent and operating condition parameters of the large vibrating screen can be obtained from the scale-down model conveniently, which provides an effective method for structural optimization and substructure coupling analysis of the large vibrating screen.

Development an Urban Rail Transit Network Scale Model

2012 ◽  
Vol 253-255 ◽  
pp. 1843-1846
Author(s):  
Xin Xin ◽  
Yan Yong Guo ◽  
Yao Wu ◽  
Ti Song
Keyword(s):  
Paper Analysis ◽  
Urban Rail Transit ◽  
Scale Model ◽  
Rail Transit ◽  
Important Indicator ◽  
Traffic Demand ◽  
Transit Network ◽  
Urban Rail ◽  
Network Scale ◽  
Urban Rail Transit Network

The network scale is an important indicator of the urban rail transit. In order to determine a reasonable scale of rail transit network, this paper analysis the influencing factors of the urban rail transit network scale. Furthermore, the main indicators of the network are summed up and analyzed. And a model of rail transit network scale is proposed based on the traffic demand. Finally, a case study of Xi'an is used to validate the model. The result shows that the model is effective and practical.

Application Research of Similarity Theory and Scale Model in Sound Barrier Noise Test

ICCTP 2010 ◽  
2010 ◽  
Author(s):  
Yan Liu ◽  
Bing Yang ◽  
Xiaopai Zhang ◽  
Jitan Guo ◽  
Bin Huang ◽  
...  
Keyword(s):  
Similarity Theory ◽  
Scale Model ◽  
Application Research ◽  
Sound Barrier ◽  
Noise Test

scholarly journals Urban-Scale Computational Fluid Dynamics Simulations with Boundary Conditions from Similarity Theory and a Mesoscale Model

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5624
Author(s):  
Demetri Bouris ◽  
Athanasios G. Triantafyllou ◽  
Athina Krestou ◽  
Elena Leivaditou ◽  
John Skordas ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Boundary Conditions ◽  
Similarity Theory ◽  
Weather Prediction ◽  
Scale Model ◽  
Design Parameters ◽  
Vertical Profiles ◽  
Atmospheric Conditions ◽  
Microscale Simulations

Mesoscale numerical weather prediction models usually provide information regarding environmental parameters near urban areas at a spatial resolution of the order of thousands or hundreds of meters, at best. If detailed information is required at the building scale, an urban-scale model is necessary. Proper definition of the boundary conditions for the urban-scale simulation is very demanding in terms of its compatibility with environmental conditions and numerical modeling. Here, steady-state computational fluid dynamics (CFD) microscale simulations of the wind and thermal environment are performed over an urban area of Kozani, Greece, using both the k-ε and k-ω SST turbulence models. For the boundary conditions, instead of interpolating vertical profiles from the mesoscale solution, which is obtained with the atmospheric pollution model (TAPM), a novel approach is proposed, relying on previously developed analytic expressions, based on the Monin Obuhkov similarity theory, and one-way coupling with minimal information from mesoscale indices (Vy = 10 m, Ty = 100 m, L*). The extra computational cost is negligible compared to direct interpolation from mesoscale data, and the methodology provides design phase flexibility, allowing for the representation of discrete urban-scale atmospheric conditions, as defined by the mesoscale indices. The results compared favorably with the common interpolation practice and with the following measurements obtained for the current study: SODAR for vertical profiles of wind speed and a meteorological temperature profiler for temperature. The significance of including the effects of diverse atmospheric conditions is manifested in the microscale simulations, through significant variations (~30%) in the critical building-related design parameters, such as the surface pressure distributions and local wind patterns.

Research on the Design Method of a Scale Model of ECC Reinforced Concrete Precast Shear Wall Structure

2016 ◽  
Vol 858 ◽  
pp. 29-33
Author(s):  
Jian Yang ◽  
Shu Ting Liang ◽  
Xiao Jun Zhu ◽  
Dong Yue Wu ◽  
Guang Yun Wang
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
Similarity Theory ◽  
Design Method ◽  
Precast Concrete ◽  
Shear Wall ◽  
Scale Model ◽  
Wall Structure ◽  
Model Structure ◽  
Precast Shear Wall

Engineered cementitious composite (ECC) is a class of high performance cementitious composites with pseudo strain hardening behavior and excellent crack control. Substitution of concrete with ECC can avoid the cracking and durability problems associated with brittleness of concrete. In this paper, it is aimed to design a scale model of ECC reinforced concrete precast shear wall structure. Referencing the prototype structure which is a precast concrete shear wall structure in Nantong, Jiangsu Province, China, the size similarity constant is taken as 1/2. Consulting the scale similarity conditions, the similarity similar constants representing material characteristics, geometrical features, and load characteristics are calculated using the strength similarity theory. Besides, the reinforcements in the model structure are calculated and analyzed. The diameters of reinforcing steel bars in the model structure are determined by the principle of similar size. Equivalent principle of yield bearing capacity are used when there is no corresponding reinforcement selection. The research results of this paper will provide valuable preferences for design and analysis of ECC reinforced concrete precast shear wall structure.

Experimental Investigation of Wave Loads Based on Trimaran Self-Propulsion Model

2016 ◽  
Author(s):  
Wei Xiaobo ◽  
Huilong Ren ◽  
Yanlong Sun ◽  
Di Wang ◽  
Zhen Yu Wang
Keyword(s):  
Model Test ◽  
High Speed ◽  
High Performance ◽  
Similarity Theory ◽  
Scale Model ◽  
Comprehensive Model ◽  
Wave Loads ◽  
Test Results ◽  
Regular Waves ◽  
Test Study

Trimaran, as a high performance ship, its special ship form is different from regular monohull ship. The particular characteristics of longitudinal and transverse wave loads are concerned greatly by ship structure designers. Theoretical methods for forecasting the wave loads of trimaran are under developing. And the relative comprehensive model test study of trimaran’s wave loads is rare in the publication. In this paper, the trimaran model test had been carried out in the tank. According to similarity theory and simulation of stiffness, a scale model of trimaran with measurement system had been manufactured. Then the segmented model had navigated in regular waves of different sea conditions. Through analysis of the experimental data, the wave loads characteristics of this trimaran are presented. A comparison of test results and theoretical values is also made to show the similarities and differences. This study can provide some useful information for further design of high-speed trimaran in the point of wave loads, which maybe a reference for research of trimaran.

Experimental Study and Finite Element Analysis on Dynamic Property of the Reinforced Concrete Frame-Bent Structure

2011 ◽  
Vol 243-249 ◽  
pp. 5223-5226
Author(s):  
Xiao Hong Bai ◽  
Lei Xie ◽  
Tao Wang
Keyword(s):  
Dynamic Property ◽  
Large Scale ◽  
Similarity Theory ◽  
Dynamic Properties ◽  
Thermal Power ◽  
Scale Model ◽  
Original Structure ◽  
Reinforced Concrete Frame ◽  
Element Analysis ◽  
Concrete Frame

Based on the R.C. frame-bent structure in a large-scale thermal power plant’s main building, a 1/7 scale model has been tested by man-excitaiton to determine its’ dynamic properties. The former three frequencies and vibration modes of the model are obtained, and the dynamic property of the original structure is studied based on model similarity theory. At last, modal analysis of plane model and spatial model of prototype are discussed by using ANSYS FEA software, and the spatial dynamic preperty of the irregular structure is analyzed.

scholarly journals Large-Eddy Simulation of Stratified Turbulence. Part I: A Vortex-Based Subgrid-Scale Model

2014 ◽  
Vol 71 (5) ◽  
pp. 1863-1879 ◽  
Author(s):  
Daniel Chung ◽  
Georgios Matheou
Keyword(s):  
Kinetic Energy ◽  
Large Eddy Simulation ◽  
Similarity Theory ◽  
Scale Model ◽  
Extended Model ◽  
Subgrid Scale ◽  
Stratified Turbulence ◽  
Vortex Model ◽  
Eddy Simulation ◽  
Large Eddy

Abstract The stretched-vortex subgrid-scale (SGS) model is extended to enable large-eddy simulation of buoyancy-stratified turbulence. Both stable and unstable stratifications are considered. The extended model retains the anisotropic form of the original stretched-vortex model, but the SGS kinetic energy and the characteristic SGS eddy size are modified by buoyancy subject to two constraints: first, the SGS kinetic energy dynamics is determined by stationary and homogeneous conditions, and second, the SGS eddy size obeys a scaling analogous to the Monin–Obukhov similarity theory. The SGS model construction, comprising an ensemble of subgrid stretched-vortical structures, naturally limits vertical mixing but allows horizontal mixing provided the alignment of the SGS vortex ensemble is favorable, even at high nominal gradient Richardson numbers. In very stable stratification, the model recovers the z-less limit, in which a vortex-based Obukhov length controls the SGS dynamics, while in very unstable stratification, the model recovers the free-convection limit, in which a vortex-based Deardorff velocity controls the SGS dynamics. The efficacy of the present SGS model is demonstrated by simulating the canonical stationary and homogeneous, stratified sheared turbulence at high Reynolds numbers and moderately high Richardson numbers. In the postprocessing, the SGS dynamics of the stretched-vortex model is further interrogated to yield predictions of buoyancy-adjusted one-dimensional SGS spectra and SGS root-mean-square velocity-derivative fluctuations.

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