scholarly journals Dynamic Characteristics of Metro Trains under Rescue Conditions

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Ruiming Zou ◽  
Shihui Luo ◽  
Weihua Ma ◽  
Qing Wu
Keyword(s):  
Dynamic Characteristics ◽  
Dynamic Performance ◽  
Field Tests ◽  
Test Results ◽  
Nonlinear Characteristics ◽  
Nonlinear Hysteresis ◽  
Longitudinal Dynamic ◽  
Draft Gear ◽  
Simulation Results ◽  
Hysteresis Characteristics

In order to study the dynamic characteristics of metro train under rescue conditions, a detailed dynamic model with different train formations is established, taking into account the characteristics of wheel-rail contact, nonlinear characteristics of suspension components, and nonlinear hysteresis characteristics of the draft gear systems. To verify the accuracy of the simulation results, field tests are carried out and comparison is made between simulation and test results. Then, simulation analyses are conducted under the condition of AW0 rescues AW0, AW0 rescues AW3, and AW3 rescues AW3. Based on the simulation results, the longitudinal dynamic characteristics of the train under different rescue conditions are compared, and the influence of the longitudinal impulse on the dynamic performance of coupler and vehicle is analyzed. Finally, some suggestions are put forward to improve the draft gear as well as the rescue method.

Dynamic Response of Eccentric Swinging Sheet Transfer Mechanism with Kinematic Pair Clearances

2013 ◽  
Vol 312 ◽  
pp. 182-185
Author(s):  
Fang Cai ◽  
Jian Qing Zhang ◽  
Xiu Feng Ma
Keyword(s):  
Dynamic Response ◽  
Dynamic Characteristics ◽  
Dynamic Performance ◽  
Transfer Mechanism ◽  
Kinematic Pair ◽  
Nonlinear Dynamic Response ◽  
Nonlinear Characteristics ◽  
Continuous Contact ◽  
The Stability ◽  
Transfer Mechanisms

To research the influence of kinematic pair clearances on the dynamic performance of eccentric swinging sheet transfer mechanism used in Sheet-fed offset J2108, a dynamic model was established based on the clearances characteristics and the continuous contact hypothesis. Consequently, the dynamic characteristics of sheet transfer mechanisms output can be researched quantitatively. The results indicate that sheet transfer mechanisms dynamic response appears strong nonlinear characteristics while considering kinematic pair clearances, which seriously affects the sheet transfer mechanisms stability and precision. Therefore, the study on the nonlinear dynamic response of sheet transfer mechanism can provide foundation to improve the stability.

Modelling building infiltration using the airflow network model approach calibrated by air-tightness test results and leak detection

2020 ◽  
Vol 41 (6) ◽  
pp. 681-693 ◽  
Author(s):  
Dariusz Heim ◽  
Artur Miszczuk
Keyword(s):  
Steady State ◽  
Computational Modelling ◽  
Field Tests ◽  
Climatic Conditions ◽  
Test Results ◽  
Air Infiltration ◽  
Steady State Method ◽  
Air Tightness ◽  
State Method ◽  
Simulation Results

This paper presents a computational approach to air infiltration modelling and simulation validated by the blower door test results. In order to evaluate the potential of the airflow network method, three simulation models of the infiltration test were developed and calibrated by field measurements of leaked air change rate per hour at 50 Pa. Models were developed for existing building designs and constructed in low-energy standards differing in construction type and tightness. All leaks were precisely measured during field tests, defined as openings or cracks, numerically described and included in the model. The simulation results of calibrated models for other pressure differences revealed that the models’ accuracy is satisfactory. The differences between field tests and simulation results do not exceed 2.5%. Additionally, the calibrated models were used to estimate the infiltration heat losses of buildings in three different locations under continental climatic conditions. The results were compared with the steady-state method calculations made for the same building models and climatic conditions. It was proved that the steady-state method gives higher results of heat demand to cover infiltration losses than the simulation method. The final results depend on building location and vary between four and nine times. Practical application: The computational modelling and building performance simulations are increasingly commonly used in engineering design. The proposed method of air-tightness modelling and calibration can be used at any phase of a building’s lifecycle, from design and construction to exploitation and maintenance. Using the proposed techniques, it is possible to estimate more realistic processes of air infiltration and its effect on a building’s energy consumption in comparison with the steady-state method. Moreover, the analysis includes the dynamic effect of boundary conditions (external air temperature, wind speed and direction), as well as the effects of the building site and the surroundings.

scholarly journals Design Process of a Helical Flux Compression Generator

2018 ◽  
Vol 215 (4) ◽  
pp. 29-45
Author(s):  
Mariusz Makowski ◽  
Marta Czarnowska ◽  
Karol Biernacki ◽  
Rafał Namiotko
Keyword(s):  
Design Process ◽  
High Explosive ◽  
Field Tests ◽  
Mechanical Parameters ◽  
Test Results ◽  
Explosive Material ◽  
Model And Simulation ◽  
Flux Compression ◽  
Inner Diameter ◽  
Simulation Results

Abstract The article demonstrates the design process of a flux compression generator. Several armature configurations and materials have been analyzed. The influence of mechanical parameters, such as wall thickness, inner diameter of the armature or high explosive material used, on FCG performance has been estimated. The geometry of generators’ components has been optimized using the Finite Elements Method. Several generators have been built based on mathematical model and simulation results. The designed FCG’s performance has been verified during field tests. A comparison of simulation and field test results has been presented.

scholarly journals A virtual prototype for performance analysis of electropneumatic brake on metro trains

2020 ◽  
Vol 12 (6) ◽  
pp. 168781402092627
Author(s):  
Jianyong Zuo ◽  
Jingxian Ding ◽  
Cheng Liu ◽  
Zhuojun Luo
Keyword(s):  
Performance Analysis ◽  
Field Test ◽  
Field Tests ◽  
Virtual Prototype ◽  
Bench Test ◽  
Initial Speed ◽  
Test Results ◽  
Braking Distance ◽  
Simulation Results ◽  
And Performance

In order to facilitate system design and performance analysis, a virtual prototype for metro train electropneumatic brakes is proposed. A virtual braking environment that consists of a three-car train model and six electropneumatic brakes model is elaborated. The virtual braking environment can be used to research the relation between braking response and electropneumatic brake’s parameters and to simulate axle loading transfer. By comparing the simulation results with bench test data, the electropneumatic brake model is proven to be quite accurate. Based on the proposed virtual prototype, a test train brake is designed, and a couple of field tests are carried out. The average deceleration of electropneumatic compound service brake at the initial speed of 45 km/h is 0.83 m/s2, the braking distance is 94 m, and that of pure air service brake at the speed of 43 km/h is 0.64 m/s2, the braking distance is 111 m. The field test results satisfy the test train requirements, which further proves the effectiveness of the proposed virtual prototype.

Simulation of Isolation Performance of Hydraulic Suspension System

2013 ◽  
Vol 668 ◽  
pp. 433-436
Author(s):  
Feng Yan Yi ◽  
Rong Chun Guo ◽  
Mei Zhi Xie
Keyword(s):  
Dynamic Characteristics ◽  
Model Theory ◽  
Simplified Model ◽  
Test Results ◽  
Power Train ◽  
Light Duty ◽  
Working Principle ◽  
Simulation Results ◽  
Isolation Performance ◽  
Dynamics Characteristic

This paper takes the power-train of domestic a light-duty bus and its hydraulic damped mounting system as the study object. Firstly, based on the analysis of hydraulic mount's structure, working Principle and ideal dynamic characteristics, its dynamic characteristics test results of hydraulic suspension are obtained. And then using MATLAB software calculates simulation of the dynamics characteristic of the hydraulic mount system. Comparing simulation results with the testing results, they are consistent well. So the simulation model is accurate, and it provides a simplified model theory for actual study, and this simplified model is more easily available.

Study and design of dual stator permanent magnet machine with spoke-type configurations using phase-group concentrated-coil windings

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1381-1389
Author(s):  
Dezhi Chen ◽  
Chengwu Diao ◽  
Zhiyu Feng ◽  
Shichong Zhang ◽  
Wenliang Zhao
Keyword(s):  
Permanent Magnet ◽  
Permanent Magnets ◽  
Low Cost ◽  
Dynamic Performance ◽  
Torque Ripple ◽  
Permanent Magnet Machine ◽  
Torque Density ◽  
Phase Group ◽  
High Torque ◽  
Simulation Results

In this paper, a novel dual-stator permanent magnet machine (DsPmSynM) with low cost and high torque density is designed. The winding part of the DsPmSynM adopts phase-group concentrated-coil windings, and the permanent magnets are arranged by spoke-type. Firstly, the winding structure reduces the amount of copper at the end of the winding. Secondly, the electromagnetic torque ripple of DsPmSynM is suppressed by reducing the cogging torque. Furthermore, the dynamic performance of DsPmSynM is studied. Finally, the experimental results are compared with the simulation results.

Modeling and Design of Permanent Magnet Vibration-to-Electrical Power Generator’s Induction Coil

2012 ◽  
Vol 588-589 ◽  
pp. 614-617
Author(s):  
Zhi Hua Wang ◽  
Mei Ling Li ◽  
Jian Zhang ◽  
Li Wang ◽  
Yong Xu
Keyword(s):  
Permanent Magnet ◽  
Electrical Power ◽  
Induction Coil ◽  
Test Results ◽  
Coil Design ◽  
Sinusoidal Vibration ◽  
Electrical Generator ◽  
Simulation Results ◽  
Peak Value

The Equivalent Turn Number of Coil (ETNC) is proposed for induction coil design. Simulation results show that the vibrationonthe induction coil’s structure. The optimized coil is composed by two symmetry parts on the condition of sinusoidal vibration. The effective value of output EMF of optimized coil increases 51.39% than uniform coil’s. In the experiment, the optimized and uniform coils are fabricated with 600 turns and comparatively studied in the same vibration-to-electrical generator. The test results show that the peak-to-peak value and effective value of output EMF of the optimized coil can increase up to 52.59% and 48.76%, respectively, compared with the uniform coil.

Comprehensive Analysis for Influence of Controllable Damper Time Delay on Semi-Active Suspension Control Strategies

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Yechen Qin ◽  
Feng Zhao ◽  
Zhenfeng Wang ◽  
Liang Gu ◽  
Mingming Dong
Keyword(s):  
Time Delay ◽  
Dynamic Characteristics ◽  
Ride Comfort ◽  
Hybrid Control ◽  
Sliding Mode ◽  
Control Strategies ◽  
Active Suspension ◽  
Test System ◽  
Suspension Control ◽  
Simulation Results

This paper presents a comprehensive comparison and analysis for the effect of time delay on the five most representative semi-active suspension control strategies, and refers to four unsolved problems related to semi-active suspension performance and delay mechanism that existed. Dynamic characteristics of a commercially available continuous damping control (CDC) damper were first studied, and a material test system (MTS) load frame was used to depict the velocity-force map for a CDC damper. Both inverse and boundary models were developed to determine dynamic characteristics of the damper. In addition, in order for an improper damper delay of the form t+τ to be corrected, a delay mechanism of controllable damper was discussed in detail. Numerical simulation for five control strategies, i.e., modified skyhook control SC, hybrid control (HC), COC, model reference sliding mode control (MRSMC), and integrated error neuro control (IENC), with three different time delays: 5 ms, 10 ms, and 15 ms was performed. Simulation results displayed that by changing control weights/variables, performance of all five control strategies varied from being ride comfort oriented to being road handling oriented. Furthermore, increase in delay time resulted in deterioration of both ride comfort and road handling. Specifically, ride comfort was affected more than road handling. The answers to all four questions were finally provided according to simulation results.

scholarly journals Experiment and simulation about the effect of wear-ring abrasion on the performance of a marine centrifugal pump

2021 ◽  
Vol 13 (2) ◽  
pp. 168781402199811
Author(s):  
Wu Xianfang ◽  
Du Xinlai ◽  
Tan Minggao ◽  
Liu Houlin
Keyword(s):  
Numerical Simulation ◽  
Centrifugal Pump ◽  
Pressure Pulsation ◽  
Vibration Velocity ◽  
Test Results ◽  
Obvious Effect ◽  
Performance Change ◽  
Pump Test ◽  
Simulation Results ◽  
Axis Passing

The wear-ring abrasion can cause performance degradation of the marine centrifugal pump. In order to study the effect of front and back wear-ring clearance on a pump, test and numerical simulation were used to investigate the performance change of a pump. The test results show that the head and efficiency of pump decrease by 3.56% and 9.62% respectively at 1.0 Qd due to the wear-ring abrasion. Under 1.0 Qd, with the increase of the front wear-ring the vibration velocity at pump foot increases from 0.4 mm/s to 1.0 mm/s. The axis passing frequency (APF) at the measuring points increases significantly and there appears new characteristic frequency of 3APF and 4APF. The numerical simulation results show that the front wear-ring abrasion affects the flow at the inlet of the front chamber of the pump and impeller passage. And the back wear-ring abrasion has obvious effect on the flow in the back chamber of the pump and impeller passage, while the multi-malfunction of the front wear-ring abrasion and back wear-ring abrasion has the most obvious effect on the flow velocity and flow stability inside pump. The pressure pulsation at Blade Passing Frequency (BPF) of the three schemes all decrease with the increase of the clearance.

Numerical simulation and field test study of desulfurization wastewater evaporation treatment through flue gas

2014 ◽  
Vol 70 (7) ◽  
pp. 1285-1291 ◽  
Author(s):  
Jia-jia Deng ◽  
Liang-ming Pan ◽  
De-qi Chen ◽  
Yu-quan Dong ◽  
Cheng-mu Wang ◽  
...  
Keyword(s):  
Field Test ◽  
Flue Gas ◽  
Cfd Simulation ◽  
Electrostatic Precipitator ◽  
Negative Impact ◽  
Positive Impact ◽  
Field Tests ◽  
Gas Temperature ◽  
Simulation Results ◽  
Desulfurization Wastewater

Aimed at cost saving and pollution reduction, a novel desulfurization wastewater evaporation treatment system (DWETS) for handling wet flue gas desulfurization (WFGD) wastewater of a coal-fired power plant was studied. The system's advantages include simple process, and less investment and space. The feasibility of this system has been proven and the appropriate position and number of nozzles, the spray droplet size and flue gas temperature limitation have been obtained by computational fluid dynamics (CFD) simulation. The simulation results show that a longer duct, smaller diameter and higher flue gas temperature could help to increase the evaporation rate. The optimal DWETS design of Shangdu plant is 100 μm droplet sprayed by two nozzles located at the long duct when the flue gas temperature is 130 °C. Field tests were carried out based on the simulation results. The effects of running DWETS on the downstream devices have been studied. The results show that DWETS has a positive impact on ash removal efficiency and does not have any negative impact on the electrostatic precipitator (ESP), flue gas heat exchanger and WFGD. The pH values of the slurry of WFGD slightly increase when the DWETS is running. The simulation and field test of the DWETS show that it is a feasible future technology for desulfurization wastewater treatment.

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