Creep Effect on the Dynamic Response of Train-Track-Continuous Bridge System

2021 ◽  
pp. 2150139
Author(s):  
Ping Xiang ◽  
Minglong Wei ◽  
Mengmeng Sun ◽  
Qiusheng Li ◽  
Lizhong Jiang ◽  
...  
Keyword(s):  
High Speed ◽  
Great Influence ◽  
Residual Deformation ◽  
Train Track ◽  
Running Safety ◽  
Finite Element Software ◽  
Numerical Predictions ◽  
Creep Effect ◽  
Bridge Model ◽  
Moving Train

The influence of track irregularity and deck deformation on the running safety of high-speed railway (HSR) trains is investigated, with emphasis placed on those caused by the creep of continuous prestressed bridges. A bridge model is established with CRTS II ballastless track to account for a train-track-bridge (TTB) system. The creep effect is calculated by the finite element software MIDAS/Civil. The accuracy of the numerical simulation is confirmed by comparing the numerical predictions with field measurements. Considering the stability index of the moving train, the deformation threshold for safe operation of the train is determined. The results show that the initial prestressing stress has a great impact on the residual deformation of the bridge, but the deformation of the rail is less affected by the stiffness of the fastener. Creep irregularity has a great influence on the comfort of the moving train, but does not affect its running safety. When the creep amplitude is greater than 4[Formula: see text]mm, the increase in the amplitude of the creep irregularity has a greater effect on the acceleration of the car body.

Numerical Simulation for Residual Stress and Deformation of Surface Welding on Membrane Water-Wall

2014 ◽  
Vol 490-491 ◽  
pp. 594-599
Author(s):  
Fan Ling Meng ◽  
Ai Guo Liu
Keyword(s):  
Residual Stress ◽  
Great Influence ◽  
Residual Deformation ◽  
Welding Residual Stress ◽  
Finite Element Software ◽  
Welding Sequence ◽  
Surface Welding ◽  
Stress And Deformation ◽  
Welding Sequences ◽  
Residual Stress And Deformation

Automatic MIG was adopted to weld Inconel 625 alloy on 20 G Membrane Waterwall, which can improve the capacities of high temperature corrosion resistance and wear resistance. To study the influence of Membrane Waterwall surface welding sequences on residual stress and residual deformation, this paper utilized finite element software ABAQUS and segmented moving heat source model to simulate the sequence welding, balanced welding from the middle to sides, balanced welding from sides to the middle, balanced skip welding from middle to sides and balanced skip welding from sides to the middle and studied their residual stresses and deformations. The simulation results indicated that there was a great influence of welding sequences on the residual stress and deformation. The optimal welding sequence was balanced skip welding from middle to sides and balanced skip welding from sides to the middle, which could change the stress distribution, decrease the welding residual stress by 17%, realize the even deformation of the whole welding section and decrease the bending deformation by 50%.

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.

Prestressed Modal Analysis of the Wind Turbine Rotor Based on ANSYS Workbench

2013 ◽  
Vol 327 ◽  
pp. 301-305 ◽  
Author(s):  
Zhi Qiang Xu
Keyword(s):  
Wind Turbine ◽  
High Speed ◽  
Geometric Model ◽  
Turbine Blades ◽  
Great Influence ◽  
Turbine Rotor ◽  
Algorithm Selection ◽  
Finite Element Software ◽  
Dynamic Stiffening ◽  
Stiffening Effect

The high speed rotating prestress makes wind turbine blades produce the dynamic stiffening effect, which has great influence on the strength of the blade and the resonance frequency. The geometric model of the rotor is established in the 3D drawing software. Based on the finite element software, the meshing, the algorithm selection and material properties are discussed respectively. The modal simulation results of the prestressed condition and no prestress state are compared. The dynamic stiffening effect increases the blade original natural frequency.

Running safety evaluation of high-speed train subject to the impact of floating ice collision on bridge piers

2021 ◽  
pp. 095440972110100
Author(s):  
Penghao Li ◽  
Zhonglong Li ◽  
Zhaoling Han ◽  
Shengyang Zhu ◽  
Wanming Zhai ◽  
...  
Keyword(s):  
High Speed ◽  
Ride Comfort ◽  
Dynamic Responses ◽  
Impact Loads ◽  
High Speed Train ◽  
Train Track ◽  
Railway Bridges ◽  
Running Safety ◽  
Track Bridge ◽  
The Impact

In Northeast China and the areas along Sichuan-Tibet railway, collision between floating ice and piers of railway bridges seriously threatens the train operation safety. The safety of high-speed train running on the bridge subject to the impact of floating ice collision is rarely assessed considering the spatial interaction of the train-track-bridge-ice system. To evaluate the running safety and ride comfort of trains and the structural stability of railway bridges under the collision between floating ices and piers, a train-track-bridge (TTB) dynamic interaction model considering the impact of floating ice is established. Using the refined finite element model, the collision process of floating ice on bridge pier is simulated, and the impact loads are employed as the excitation input of the TTB dynamics model. Taking a 5 × 32 m simply-supported bridges as a case study, the influence of bridge structural parameters on the floating ice collision system is investigated, and then the dynamic responses of the TTB system induced by the floating ice impact loads are analyzed in detail. Finally, the effect of the ice impact loads on the running safety of the high-speed train is revealed. Results show that under the floating ice impact loads, the angle of the pier sharp-nose (APSN) and lateral stiffness of foundations are the key parameters that influence the dynamic responses of the bridge, and an improperly small lateral stiffness of foundation would lead to an instability of bridge structure. The influence of ice impact loads on the dynamic responses of the train is remarkable. The lateral vibration acceleration, derailment factor and lateral wheel rail force caused by the ice impact loads are all greater than those caused by the track irregularity, while the wheel unloading rate is slightly smaller. In addition, the running speed of train is also closely related to the running safety and ride comfort when the collision occurs. When the train speed exceeds 400 km/h, the train passing through the bridge would have the possibility of derailment.

scholarly journals Effects of Groundwater Exploitation on Embankment for High-speed Railway Lines

2015 ◽  
Vol 9 (1) ◽  
pp. 417-422
Author(s):  
Luwei Huang ◽  
Hong Xiao ◽  
Song Yang ◽  
Yugang Han
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Great Influence ◽  
Coupling Model ◽  
High Speed Railway ◽  
Pumping Rate ◽  
Groundwater Exploitation ◽  
Finite Element Software ◽  
Train Operation ◽  
Pumping Rates

Groundwater exploitation will cause significant subsidence to the ground, then influence the deformation of embankment for high-speed railway lines, which may threaten the safety of train operation. To study the law of embankment deformation aroused by groundwater exploitation near high-speed railway lines, a 3D fluid-solid coupling model is established based on infiltrating solidification theory and using finite element software ABAQUS, and embankment deformations caused by different pumping rates and pumping distance are analyzed. The results show that pumping rate and pumping distance are both of great influence on the deformations of embankment for high-speed railway lines. Therefore, in order to control the effects of groundwater exploitation on embankment, it should be forbidden to add new pumping well near the railway lines and groundwater exploitation should be strictly limited within the influence scope.

scholarly journals Research and Fabrication of Broadband Ring Flextensional Underwater Transducer

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1548
Author(s):  
Jiuling Hu ◽  
Lianjin Hong ◽  
Lili Yin ◽  
Yu Lan ◽  
Hao Sun ◽  
...  
Keyword(s):  
High Speed ◽  
Structural Parameters ◽  
Low Frequency ◽  
Flexural Vibration ◽  
Underwater Acoustic Communication ◽  
Voltage Response ◽  
Water Tank ◽  
Spherical Cap ◽  
Finite Element Software ◽  
Underwater Transducer

At present, high-speed underwater acoustic communication requires underwater transducers with the characteristics of low frequency and broadband. The low-frequency transducers also are expected to be low-frequency directional for realization of point-to-point communication. In order to achieve the above targets, this paper proposes a new type of flextensional transducer which is constructed of double mosaic piezoelectric ceramic rings and spherical cap metal shells. The transducer realizes broadband transmission by means of the coupling between radial vibration of the piezoelectric rings and high-order flexural vibration of the spherical cap metal shells. The low-frequency directional transmission of the transducer is realized by using excitation signals with different amplitude and phase on two mosaic piezoelectric rings. The relationship between transmitting voltage response (TVR), resonance frequency and structural parameters of the transducer is analyzed by finite element software COMSOL. The broadband performance of the transducer is also optimized. On this basis, the low-frequency directivity of the transducer is further analyzed and the ratio of the excitation signals of the two piezoelectric rings is obtained. Finally, a prototype of the broadband ring flextensional underwater transducer is fabricated according to the results of simulation. The electroacoustic performance of the transducer is tested in an anechoic water tank. Experimental results show that the maximum TVR of the transducer is 147.2 dB and the operation bandwidth is 1.5–4 kHz, which means that the transducer has good low-frequency, broadband transmission capability. Meanwhile, cardioid directivity is obtained at 1.4 kHz and low-frequency directivity is realized.

Running safety evaluation of a 350 km/h high-speed freight train negotiating a curve based on the arbitrary Lagrangian-Eulerian method

2021 ◽  
pp. 095440972098628
Author(s):  
Gongxun Deng ◽  
Yong Peng ◽  
Chunguang Yan ◽  
Boge Wen
Keyword(s):  
High Speed ◽  
Safety Evaluation ◽  
Interaction Model ◽  
Arbitrary Lagrangian Eulerian ◽  
Railway Transportation ◽  
Freight Train ◽  
Fluid Structure ◽  
Running Safety ◽  
Study Results ◽  
Fill Level

To adapt to the rapid growth of the logistics market and further improve the competitiveness of railway transportation, the high-speed freight train with a design speed of 350 km/h is being developed in China. The safety of the train under great axle load of 17 t and dynamic load is unknown. This paper is aimed to study the running safety of the high-speed freight train coupled with various cargo loading conditions negotiating a sharp curve at high velocity. A numerical model integrated a fluid-structure coupled container model and the nonlinear high-speed freight train was set up by the software of LS-DYNA. The fluid-structure interaction model between the container and fluid cargo was established using the Arbitrary Lagrangian-Eulerian (ALE) method. Two influencing parameters, including the cargo state in the container and the fill level, were selected. The study results showed that the wheelset unloading ratio and overturning coefficient could be significantly affected by the liquid sloshing, while the influence of sloshing on the risk of derailment was slight. In general, increasing the cargo filling rate would contribute to vehicle operation safety. In conclusion, this study would provide theoretical help for the running safety of the newly designed high-speed freight train.

Numerical Modeling and Simulation Analysis of Temperature Field of Disc Brake on Trains

2011 ◽  
Vol 199-200 ◽  
pp. 1492-1495 ◽  
Author(s):  
Guo Shun Wang ◽  
Rong Fu ◽  
Liang Zhao
Keyword(s):  
Temperature Field ◽  
Temperature Gradient ◽  
High Speed ◽  
Large Scale ◽  
Working Condition ◽  
Constant Speed ◽  
Brake Disc ◽  
Disc Brake ◽  
Brake Pad ◽  
Finite Element Software

The simulation calculation on the temperature field of the disc brake system on high-speed trains under the working condition of constant speed at 50Km/h is made. A steady-state calculation model is established according to the actual geometric size of a brake disc and a brake pad, and the analog calculation and simulation on the temperature field of the brake disc and the brake pad by using the large-scale nonlinear finite element software ABAQUS are carried out. The distribution rules of the temperature field of the brake disc and the brake pad under the working condition of constant speed are made known. The surface temperature of the brake disc at friction radius is the highest, with a band distribution for temperature. There exists a temperature flex point in the direction of thickness, of which the thickness occupies 15% of that of the brake disc; due to the small volume of the brake pad, the temperature gradient of the whole brake pad is not sharp, and larger temperature gradient occurs only on the contact surface.

Stochastic Transverse Earthquake-Induced Damage Track Irregularity Spectrum Considering the Uncertainty of Track-Bridge System

2021 ◽  
pp. 2140004
Author(s):  
Yulin Feng ◽  
Yu Hou ◽  
Lizhong Jiang ◽  
Wangbao Zhou ◽  
Jian Yu ◽  
...  
Keyword(s):  
Simulation Model ◽  
Traffic Safety ◽  
High Speed ◽  
Residual Deformation ◽  
High Speed Railway ◽  
Marquardt Algorithm ◽  
Earthquake Action ◽  
Track Irregularity ◽  
Track Bridge ◽  
Bridge System

The track irregularity spectrum of longitudinally connected ballastless track (LCBT)-bridge systems of high-speed railway was proposed in this paper. First, a simulation model of an LCBT-continuous girder bridge was established by considering the influences of approach bridges and subgrade with track structure. Further, a large number of sample analyses were carried out by taking into account the uncertainty of LCBT-bridge systems and stochastic behaviors of ground motions based on the simulation model. The damage laws of residual deformation of track-bridge system after earthquake actions were studied. Then, an interlayer deformation coordination relationship (IDCR) considering the track irregularity caused by earthquake-induced damage of bearings was developed, and the superposed track irregularity samples were obtained. Finally, by using the improved Blackman–Turkey method and Levenberg–Marquardt algorithm, the LCBT irregularity spectrum, track irregularity spectrogram, track irregularity limit spectrum, and a fitting formula for the track irregularity spectrum on a bridge after the action of earthquakes were obtained. Results obtained from the fitting formula and IDCR were compared, and they indicated that tracks undergone significant high-frequency irregularity diseases after the earthquake action. It was found that the track irregularity spectrum could be roughly divided into three ranges: high-, medium- and low-frequency wavebands. Consequently, this led to an application of a three-segment power function for the fitting of the track irregularity spectrum after the earthquake action. The track irregularity spectrum after the action of earthquakes provides an important theoretical basis for the establishment of seismic design methods for high-speed railway bridges based on the traffic safety performance.

scholarly journals Delamination Buckling and Crack Propagation Simulations in Fiber-Metal Laminates Using xFEM and Cohesive Elements

2018 ◽  
Vol 8 (12) ◽  
pp. 2440 ◽  
Author(s):  
Davide De Cicco ◽  
Farid Taheri
Keyword(s):  
Finite Element ◽  
Crack Propagation ◽  
Hybrid Composites ◽  
Cohesive Elements ◽  
Zone Method ◽  
Fiber Metal Laminates ◽  
Finite Element Software ◽  
Numerical Predictions ◽  
Delamination Buckling ◽  
Fiber Metal

Simulation of fracture in fiber-reinforced plastics (FRP) and hybrid composites is a challenging task. This paper investigates the potential of combining the extended finite element method (xFEM) and cohesive zone method (CZM), available through LS-DYNA commercial finite element software, for effectively modeling delamination buckling and crack propagation in fiber metal laminates (FML). The investigation includes modeling the response of the standard double cantilever beam test specimen, and delamination-buckling of a 3D-FML under axial impact loading. It is shown that the adopted approach could effectively simulate the complex state of crack propagation in such materials, which involves crack propagation within the adhesive layer along the interface, and its diversion from one interface to the other. The corroboration of the numerical predictions and actual experimental observations is also demonstrated. In addition, the limitations of these numerical methodologies are discussed.

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