scholarly journals An Alternative Solution of Train-Track Dynamic Interaction

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Zhaowei Chen ◽  
Hui Fang
Keyword(s):  
Calculation Method ◽  
Secondary Development ◽  
Train Track ◽  
Computational Accuracy ◽  
Explicit Integration ◽  
Application Range ◽  
Computing Platform ◽  
Development Technology ◽  
Railway Engineering ◽  
Track Bridge

Train-track interaction (TTI) is a classic research topic in railway engineering, which consists of three main parts, namely, train model, track model, and wheel-rail interaction. To improve the computational accuracy and broaden the application range, an alternative calculation method to investigate TTI based on secondary development technology of the commercial software ANSYS through APDL language is introduced in this article. Primarily, the train-track interaction theory is briefly presented. On this basis, TTI is programmed and implemented on the computing platform of ANSYS by fully taking the nonlinear wheel-rail interaction into consideration. In this calculation method, the train model, which is established based on multibody dynamics theory and solved by an advanced explicit integration method, is programmed into ANSYS through APDL language, while the track part is simulated according to finite element theory. Then, the proposed calculation method is validated with field test results to verify the validity. Finally, a numerical demonstration is conducted employing the present method. Results show that the introduced method is effective and able to investigate TTI. Different complicated track systems can be accurately simulated employing this method. Moreover, this method is also adoptable to explore train-bridge interaction and train-track-bridge interaction.

Studies on Galloping of Iced Conductor Based on Tower-Line Coupling System – Aerodynamic Loads

2012 ◽  
Vol 182-183 ◽  
pp. 1630-1633
Author(s):  
Hao Jun Hu ◽  
Yuan Han Wang ◽  
Zi Dong Hu
Keyword(s):  
Finite Element ◽  
Wind Speed ◽  
Finite Element Model ◽  
Aerodynamic Force ◽  
Element Model ◽  
Aerodynamic Characteristics ◽  
Explicit Integration ◽  
Computing Platform ◽  
Coupling System ◽  
Line Coupling

Based on the second development at the ANSYS computing platform, finite element model of a Tower-Line Coupling system was established. The computational fluid dynamics module (CFX) was used for the numerical simulation of the aerodynamic characteristics of iced conductor. On the basis of the Kaimal spectrum, fast Fourier transform was introduced to prepare the wind speed simulation program WVFS with spatial correlation into consideration, thus generating aerodynamic coefficients of iced conductor at different wind attack angles as well as wind speed time series at tower-line nodes. According to the finite element model of continuous multi-conductors and the aerodynamic force- wind attack angle curve, the explicit integration is applied for numerical solution of galloping of iced conductor.

Influences of Wind Barriers on the Train Running Safety on a Highway-Railway One-Story Bridge

2021 ◽  
pp. 2140009
Author(s):  
Ye Liu ◽  
Yan Han ◽  
Peng Hu ◽  
C. S. Cai ◽  
Xuhui He
Keyword(s):  
Dynamic Responses ◽  
Response Analysis ◽  
Train Track ◽  
Wheel Load ◽  
Wind Barrier ◽  
The Mean ◽  
Wind Pressures ◽  
Track Bridge ◽  
Fluctuating Wind ◽  
Bridge System

In this study, the influences of wind barriers on the aerodynamic characteristics of trains (e.g. a CRH2 train) on a highway-railway one-story bridge were investigated by using wind pressure measurement tests, and a reduction factor of overturning moment coefficients was analyzed for trains under wind barriers. Subsequently, based on a joint simulation employing SIMPACK and ANSYS, a wind–train–track–bridge system coupled vibration model was established, and the safety and comfort indexes of trains on the bridge were studied under different wind barrier parameters. The results show that the mean wind pressures and fluctuating wind pressures on the trains’ surface decrease generally if wind barriers are used. As a result, the dynamic responses of the trains also decrease in the whole process of crossing the bridge. Of particular note, the rate of the wheel load reductions and lateral wheel-axle forces can change from unsafe states to relative safe states due to the wind barriers. The influence of the porosity of the wind barriers on the mean wind pressures and fluctuating wind pressures on the windward sides and near the top corner surfaces of the trains are significantly greater than the influence from the height of the wind barriers. Within a certain range, decreasing the wind barrier porosities and increasing the wind barrier heights will significantly reduce the safety and comfort index values of trains on the bridge. It is found that when the porosity of the wind barrier is 40%, the optimal height of the wind barrier is determined as approximately 3.5[Formula: see text]m. At this height, the trains on the bridges are safer and run more smoothly and comfortably. Besides, through the dynamic response analysis of the wind–train–track–bridge system, it is found that the installation of wind barriers in cases with high wind speeds (30[Formula: see text]m/s) may have an adverse effect on the vertical vibration of the train–track–bridge system.

Optimization of Aircraft Mid-Fuselage Structure Design Based on Parametric Modeling

2014 ◽  
Vol 933 ◽  
pp. 423-427 ◽  
Author(s):  
Chao Ying Zhang ◽  
Hu Liu ◽  
Yun Peng Ma
Keyword(s):  
Structural Response ◽  
Aircraft Design ◽  
Element Model ◽  
Parametric Model ◽  
Structure Design ◽  
Parametric Modeling ◽  
Secondary Development ◽  
Typical Structure ◽  
Development Technology ◽  
Cae Technology

In aircraft preliminary design, fuselage structure design is important, and to reach the lightest weight is the main target for aircraft design, especially for civil aircraft. Based on CAD/CAE technology, the paper selects a typical structure layout form of aircraft mid-fuselage to study the method of structure model quickly creation and optimization. First, it focuses on fuselage parameterized modeling method, based on CATIA secondary development technology, to create the mid-fuselage parametric model. Then, based on Patran command language, the CAD model achieves automatic meshing. Finally, selecting an appropriate strategy and using iSIGHT integrated with fuselage parametric model and finite element model, and referring to the calculated the structural response by Nastran to realize mid-fuselage structure optimization.

CAD of Gating System for Injection Mold Based on the Secondary Development Technology of PRO/E

2010 ◽  
Vol 148-149 ◽  
pp. 453-457
Author(s):  
Zheng Hao Ge ◽  
Yi Qu ◽  
Ya Nan Zhou
Keyword(s):  
Flow Rate ◽  
Material Properties ◽  
Cost Reduction ◽  
Secondary Development ◽  
Injection Mold ◽  
Gating System ◽  
Second Development ◽  
Development Technology ◽  
Pressure Fall

The gating system is usually made up of the sprue, the runner, the gate and the slag well. It is an important component of the mold. On the basis of relationship among runner’s geometry, the pressure fall of plastic melt flowing in runner, flow rate and material properties, we can use the UDF library features and Pro / Toolkit functions in PRO / E software to do the second development of PRO / E software. As a result, we can establish the CAD module of gating system for the injection mold. The module has the perfect function and good generality and can help the designer for cost reduction. It may be used whenever you want to use. The PRO / E software has a powerful function to design mold. Taking these as a base, it is very convenient for the module to design the gating system of injection mold.

High-speed train–track–bridge dynamic interactions – Part I: theoretical model and numerical simulation

2013 ◽  
Vol 1 (1-2) ◽  
pp. 3-24 ◽  
Author(s):  
Wanming Zhai ◽  
He Xia ◽  
Chengbiao Cai ◽  
Mangmang Gao ◽  
Xiaozhen Li ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Theoretical Model ◽  
High Speed ◽  
High Speed Train ◽  
Train Track ◽  
Dynamic Interactions ◽  
Track Bridge

scholarly journals Train–track–bridge modelling and review of parameters

2015 ◽  
Vol 12 (9) ◽  
pp. 1051-1064 ◽  
Author(s):  
Daniel Cantero ◽  
Therese Arvidsson ◽  
Eugene OBrien ◽  
Raid Karoumi
Keyword(s):  
Train Track ◽  
Track Bridge

scholarly journals Effect of Bridge-Pier Differential Settlement on the Dynamic Response of a High-Speed Railway Train-Track-Bridge System

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Xiaohui Zhang ◽  
Yao Shan ◽  
Xinwen Yang
Keyword(s):  
Dynamic Response ◽  
High Speed ◽  
Tensile Force ◽  
Differential Settlement ◽  
Bridge Pier ◽  
Vertical Acceleration ◽  
Train Track ◽  
Allowable Limit ◽  
High Speed Railway ◽  
Track Bridge

A model based on the theory of train-track-bridge coupling dynamics is built in the article to investigate how high-speed railway bridge pier differential settlement can affect various railway performance-related criteria. The performance of the model compares favorably with that of a 3D finite element model and train-track-bridge numerical model. The analysis of the study demonstrates that all the dynamic response for a span of 24 m is slightly larger than that for a span of 32 m. The wheel unloading rate increases with pier differential settlement for all of the calculation conditions considered, and its maximum value of 0.695 is well below the allowable limit. Meanwhile, the vertical acceleration increases with pier differential settlement and train speed, respectively, and the values for a pier differential settlement of 10 mm and speed of 350 km/h exceed the maximum allowable limit stipulated in the Chinese standards. On this basis, a speed limit for the exceeding pier differential settlement is determined for comfort consideration. Fasteners that had an initial tensile force due to pier differential settlement experience both compressive and tensile forces as the train passes through and are likely to have a lower service life than those which solely experience compressive forces.

Key Technologies of Development of Intelligent Overall Layout Design System for Bus Body

2011 ◽  
Vol 121-126 ◽  
pp. 928-932
Author(s):  
Jing Xin Chen ◽  
Jing Xian Chen ◽  
Jing Zhang
Keyword(s):  
Three Dimensional ◽  
Layout Design ◽  
Parametric Modeling ◽  
Secondary Development ◽  
Design System ◽  
Database Access ◽  
Body Development ◽  
Development Technology ◽  
Bus Body ◽  
Function Module

Based on the requirements and characters of overall layout design of bus body, development process, overall structure, function module and deduction network of Intelligent Overall Layout Design System for Bus Body were built. It is illustrated systematically how the object-oriented modeling technology, deduction technology based on knowledge, secondary development technology based on CATIA, three dimensional parametric modeling methods and technology of database access etc were applied to the design and development of the system. The function of the system was verified through a case of specific bus body overall layout design.

Dynamic analysis of coupled train–track–bridge system subjected to debris flow impact

2018 ◽  
Vol 22 (4) ◽  
pp. 919-934 ◽  
Author(s):  
Xun Zhang ◽  
Zhipeng Wen ◽  
Wensu Chen ◽  
Xiyang Wang ◽  
Yan Zhu
Keyword(s):  
Debris Flow ◽  
Dynamic Analysis ◽  
High Speed ◽  
Impact Load ◽  
Dynamic Responses ◽  
Train Track ◽  
Running Safety ◽  
Track Bridge ◽  
Safety Indices ◽  
Bridge System

With the increasing popularity of high-speed railway, more and more bridges are being constructed in Western China where debris flows are very common. A debris flow with moderate intensity may endanger a high-speed train traveling on a bridge, since its direct impact leads to adverse dynamic responses of the bridge and the track structure. In order to address this issue, a dynamic analysis model is established for studying vibrations of coupled train–track–bridge system subjected to debris flow impact, in which a model of debris flow impact load in time domain is proposed and applied on bridge piers as external excitation. In addition, a six-span simply supported box girder bridge is considered as a case study. The dynamic responses of the bridge and the running safety indices such as derailment factor, offload factor, and lateral wheel–rail force of the train are investigated. Some influencing factors are then discussed based on parametric studies. The results show that both bridge responses and running safety indices are greatly amplified due to debris flow impact loads as compared with that without debris flow impact. With respect to the debris flow impact load, the boulder collision has a more negative impact on the dynamic responses of the bridge and train than the dynamic slurry pressure. Both the debris flow impact intensity and train speed determine the running safety indices, and the debris flow occurrence time should be also carefully considered to investigate the worst scenario.

scholarly journals A Feasibility Study of the Drive-By Method for Damage Detection in Railway Bridges

2019 ◽  
Vol 9 (1) ◽  
pp. 160 ◽  
Author(s):  
Marco Carnevale ◽  
Andrea Collina ◽  
Tim Peirlinck
Keyword(s):  
Structural Damage ◽  
Damage Identification ◽  
Train Track ◽  
Operational Parameters ◽  
Railway Bridges ◽  
Acceleration Sensors ◽  
Magnetic Inspection ◽  
Track Irregularity ◽  
High Level ◽  
Track Bridge

Damage identification and localization in railway bridges is a widely studied topic. Strain, displacement, or acceleration sensors installed on the bridge structure are normally used to detect changes in the global behavior of the structure, whereas approaches like ultra-sonic testing, acoustic emission, and magnetic inspection are used to check a small portion of structure near localized damage. The aim of this paper is to explore another perspective for monitoring the structural status of railway bridges, i.e., to detect structural damage from the dynamic response of the train transiting the bridge. This approach can successfully be implemented in the case of resonant bridges, thanks to the high level of acceleration generated, but its application becomes more challenging when the excitation frequencies due to train passage do not excite the first mode of vibration of the bridge. The paper investigates the feasibility of the method in the latter case, through numerical simulations of the complete train-track-bridge system. Accelerations on axleboxes and bogies are processed through suitable algorithms to detect differences arising when the train crosses a defective bridge or a healthy one. The results outline the main operational parameters affecting the method, the best placement for sensors, and the best frequency range to be considered in the signal processing, also addressing the issues that are related to track irregularity. Good performance can be achieved in the case of short bridges, but a few practical issues must be tackled before the method could be tested in practice.

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