Analysis of collision dynamics of lifting the pantograph during vehicle operation

2021 ◽  
pp. 095440972110426
Author(s):  
Yongming Yao ◽  
Ning Zhou ◽  
Guiming Mei ◽  
Weihua Zhang
Keyword(s):  
Aerodynamic Force ◽  
Engineering Problem ◽  
Contact Model ◽  
Vertical Acceleration ◽  
Collision Dynamics ◽  
Contact Wire ◽  
Vehicle Operation ◽  
Train Operation ◽  
Practical Engineering ◽  
Maximum Impact Force

It is a practical engineering problem to lift the pantograph during train operation. In this paper, a pantograph-catenary (PAC) model is established, which can realize pantograph lifting during train operation. In this model, the contact model between contact piece and contact wire is established using the polygon contact model (PCM). The PAC collision test rig is established, and the simulation model at low speed is verified by comparing the contact force and vertical acceleration of contact piece obtained from simulation and test. The factors influencing the process of pantograph lifting are analyzed. The simulation results show that the position where the dropper and contact wire are connected is the most disadvantageous position for pantograph lifting. The maximum impact force increases with the increase of pantograph lifting speed, and the relationship between them is linear. In addition, if the influence of aerodynamic force is not considered, the running speed of vehicle will not affect the pantograph lifting process.

scholarly journals The Influence of the Track Parameters on Vibration Characteristics of Subway Tunnel

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Wenbo Shi ◽  
Linchang Miao ◽  
Junhui Luo ◽  
Honglei Zhang
Keyword(s):  
Soft Soil ◽  
Power Level ◽  
Coupling Model ◽  
Calculation Model ◽  
Vertical Acceleration ◽  
Subway Tunnel ◽  
Ballastless Track ◽  
Train Operation ◽  
The Impact ◽  
Wheel Track

In soft soil areas, such as the Nanjing, it is very important to quantitatively analyze the dynamic behaviors of soft soils during the metro train operation. A nonlinear coupling model of wheel-track and a finite element calculation model of tunnel and soil were established based on the mechanical character of elastic supporting block ballastless track and the actual parameters of Nanjing soft soil. The time-variant vertical acceleration of the rail, the sleepers, and the surface of the tunnel can be calculated by the models, and the frequency dependence acceleration was verified by the fast Fourier transform algorithm. A modified vibration power level for human sensitivity was used to quantify the vibration energy of each part of the system, and the impact of the parameters in the model was evaluated. The results can be applied to the metro design and construction, which also can be the guidance during the tunnel construction.

Contact Stress Analysis of Gear of Crane Gearbox

2007 ◽  
Author(s):  
Zhonglai Wang ◽  
Bo Yang ◽  
Hong-Zhong Huang ◽  
Qiang Miao ◽  
Dan Ling
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Analysis ◽  
Contact Stress ◽  
Optimization Method ◽  
Probability Of Failure ◽  
Engineering Problem ◽  
Gear Transmission ◽  
Practical Engineering ◽  
Practical Engineering Problem

Gears are widely used in many practical engineering to transmit torque. In the process of meshing, contact stress will be produced which causes pitting. Shock becomes more and more serious with the increase of pitting and the probability of failure of meshing gears increases. Contact stress analysis is necessary and important to increase the reliability of gear transmission. In this paper, a fuzzy Hertz approximate optimization method and finite element method are used to deal with a practical engineering problem.

Research and Design of Simple Numerical Control System of Valve Block Processing

2013 ◽  
Vol 364 ◽  
pp. 280-284
Author(s):  
En Tao Zhou ◽  
Jun Zhe Lin ◽  
Lin Tao ◽  
Xiao Liang Chen ◽  
Chen Song
Keyword(s):  
Control System ◽  
Engineering Problem ◽  
Numerical Control ◽  
Numerical Control System ◽  
Plc Control ◽  
Practical Engineering ◽  
Design And Manufacture ◽  
Automatic Positioning ◽  
Research And Design ◽  
Valve Block

During the design and manufacture of hydraulic system, valve block of processing is time-consuming and labor-intensive, and its easy to make a mistake. In this paper, a simple numerical control system based on PLC control to solve the practical engineering problem is studied. An automatic positioning based on parameters of holes which are drawn by AutoCAD and an automatic machining of holes can be realized by the control system. Its also discussed that the method and process of the design of software and hardware.

Evaluation of High-Order Resonance of Blade Under Wake Excitation

2010 ◽  
Author(s):  
Lin Li ◽  
Peiyi Wang
Keyword(s):  
Force Field ◽  
Aerodynamic Force ◽  
Engineering Problem ◽  
High Order ◽  
Order Resonance ◽  
High Order Resonance ◽  
Resonance Frequencies ◽  
The Common ◽  
Turbo Machinery ◽  
Two Parameters

Avoiding the low-order resonances of blades is one of the main design goals for a mechanical structure designer of turbo machinery. However, we have to accept that there are resonance frequencies in the operating speed range of the blade, for the following reasons: Firstly, the natural frequencies of the blade are closely spaced sometimes, it is impossible to avoid them all. Secondly, in general, the higher of the resonance frequency, the lower the energy of resonance will be. But in recent 10 years, the high-order blade resonances present more and more frequently in turbo machinery, which induce a lot of HCF problems. As the considerations above, studies on the high-order vibration of blades become necessary and important. In the cascade, the high-order vibration of blades is mainly induced by the wakes from upstream. An obvious difference of the wake excitation from the common excitations resides in its asynchronism, that is, the maximum value of aerodynamic force from wakes at each point doesn’t appear at the same time, because except the frequency, the distribution of the aerodynamic force field depends on two parameters: not only amplitude but also phase angle. Both are functions of coordinates. In this paper, the related position in Euclidean Space between the asynchronous excitation field and the modal displacement of blade were deal with to evaluate the strength of the high-order resonance of blade. The effect of the asynchronous aerodynamic force field on the blade resonance was studied either. Finally a method for evaluation of high-order resonance of blade excited by wake fluid is proposed. A numerical case was studied either, which demonstrates that the proposed evaluation on high-order resonance is practical in engineering problem.

Model Validation Methods for Multiple Correlated Responses via Covariance-Overlap Based Distance

2019 ◽  
Vol 142 (4) ◽  
Author(s):  
Jiexiang Hu ◽  
Ping Jiang ◽  
Qi Zhou ◽  
Austin McKeand ◽  
Seung-Kyum Choi
Keyword(s):  
Engineering Design ◽  
Model Validation ◽  
Computational Models ◽  
Engineering Problem ◽  
Cumulative Probability ◽  
Global Evaluation ◽  
Correlated Responses ◽  
Validation Methods ◽  
Engineering Design Problems ◽  
Practical Engineering

Abstract Model validation methods have been widely used in engineering design to provide a quantified assessment of the agreement between simulation predictions and experimental observations. For the validation of simulation models with multiple correlated outputs, not only the uncertainty of the responses but also the correlation between them needs to be considered. Most of the existing validation methods for multiple correlated responses focus on the area metric, which only compares the overall area difference between the two cumulative probability distribution curves. The differences in the distributions of the data sets are not fully utilized. In this paper, two covariance-overlap based model validation (COMV) methods are proposed for the validation of multiple correlated responses. The COMV method is used for a single validation site, while the covariance-overlap pooling based model validation (COPMV) method can pool the evidence from different validation sites into a scalar measure to give a global evaluation about the candidate model. The effectiveness and merits of the proposed methods are demonstrated by comparing with three different existing validation methods on three numerical examples and a practical engineering problem of a turbine blade validation example. The influence of sample size and the number of partitions in the proposed methods are also discussed. Results show that the proposed method shows better performance on the uncertainty estimation of different computational models, which is useful for practical engineering design problems with multiple correlated responses.

Meso-Scale Oriented Physical Simulation Model for Complex Product Maintenance in Virtual Environment

2013 ◽  
Vol 706-708 ◽  
pp. 1954-1957
Author(s):  
Gao Liang Peng ◽  
Hong Liang ◽  
Xin Li
Keyword(s):  
Physical Simulation ◽  
Significant Loss ◽  
Engineering Problem ◽  
Large Component ◽  
Operation Process ◽  
Simulation Strategy ◽  
Practical Engineering ◽  
Surface Visualization ◽  
Practical Engineering Problem ◽  
Important Significance

Large component disassembly is complex tasks, the collision during the operation process often cause component damage and deform, even bring safe accident and result in significant loss. This paper proposes to use Meso-dimential oriented physical simulation strategy to research the collision effect simulation and damage surface visualization of large component during disassembly operation. Meso-collide behavior of multi-particles is adapted to simulate the macro-collision of large component. The method has important significance for expanding the mechanical simulation theory and solving the complex practical engineering problem.

Study on the Aerodynamics Mechanism of Passenger Car under Unsteady Crosswind

2013 ◽  
Vol 631-632 ◽  
pp. 809-816
Author(s):  
Chen Shen ◽  
Hui Zhu ◽  
Zhi Gang Yang
Keyword(s):  
Empirical Formula ◽  
Potential Flow ◽  
Aerodynamic Force ◽  
Vortex Motion ◽  
Flow Theory ◽  
Potential Flow Theory ◽  
Practical Engineering ◽  
Precise Prediction ◽  
Engineering Significance ◽  
Semi Empirical

Regular formulae for lateral aerodynamic force cannot give precise prediction under unsteady crosswind. By generalizing potential flow theory and taking the aerodynamic derivative into consideration, the semi-empirical expression for lateral aerodynamic force is derived. In order to determine the coefficients in the semi-empirical formula, the model of a typical double-deck coach is investigated in a sequence of numerical simulations under pure crosswind condition (i.e. linear crosswind, pseudo-step crosswind, sinusoidal crosswind). Moreover, advantages of the semi-empirical formula over the regular one are revealed. Further inspections into the flow field derived from the theory of vortex motion indicate that the deviation between the prediction given by semi-empirical formulae and that by numerical simulation is caused by the non-viscous assumption in potential flow theory. The lateral aerodynamic force depends linearly on the crosswind aerodynamic derivative. Situations in which the coach is moving in the direction perpendicular to the wind velocity are also studied to find the cause of the error in semi-empirical formula. Furthermore, the semi-empirical formula is revised by introducing the “damping model method”. A relatively complete system of prediction for lateral aerodynamic force on a coach, which is of practical engineering significance, has been constructed.

scholarly journals A Method for Estimating Aircraft Vertical Acceleration and Eddy Dissipation Rate in Turbulent Flight

2020 ◽  
Vol 10 (19) ◽  
pp. 6798
Author(s):  
Zhenxing Gao ◽  
Debao Wang ◽  
Zhiwei Xiang
Keyword(s):  
Dissipation Rate ◽  
Aerodynamic Force ◽  
Wind Tunnel Test ◽  
Control Surface ◽  
Civil Aviation ◽  
Vertical Acceleration ◽  
Pitching Moment ◽  
Continuous Change ◽  
Adverse Influence ◽  
Modeling Data

Atmospheric turbulence is a typical risk that threatens the flight safety of civil aviation aircraft. A method of estimating aircraft’s vertical acceleration in turbulence is proposed. Based on the combination of wing and horizontal tail, the continuous change of aerodynamic force in turbulent flight is obtained by unsteady vortex ring method. Vortex rings are assigned on the mean camber surface to further improve the computing accuracy. The incremental aerodynamic derivatives of lift and pitching moment are developed, which can describe the turbulence effects on aircraft. Furthermore, a new acceleration-based eddy dissipation rate (EDR) algorithm was developed to estimate the turbulence severity. Compared with wind tunnel test data, the aerodynamic performance of the lifting surface was computed accurately. A further test on wing–tail combination showed that the computed pitching moment change due to control-surface deflections approaches the aircraft-modeling data. The continuous change of vertical acceleration at any longitudinal locations of aircraft is obtained in turbulent flight. Compared with traditional transfer function-based EDR algorithms, the proposed algorithm shows higher accuracy and stability. Furthermore, the adverse influence of aircraft maneuvering on EDR estimation is eliminated.

Combined Long-Term Simulation of Runoff from Urban and Rural Areas

1990 ◽  
Vol 22 (10-11) ◽  
pp. 87-94 ◽  
Author(s):  
M. W. Ostrowski ◽  
L. Alsenz
Keyword(s):  
Rural Areas ◽  
Engineering Problem ◽  
Data Availability ◽  
Model Parameters ◽  
General Applicability ◽  
Small Catchment ◽  
Practical Engineering ◽  
Continuous Complex ◽  
Estimation Of Model Parameters ◽  
Urban And Rural Areas

It has become evident that emission control standards for stormwater overflow design are practical, but not sufficient to guarantee ecologically balanced quantity and quality characteristics of receiving natural water bodies. The quality and quantity of both stormwater overflow and the receiving water should be considered at the same time. One objective of the investigation was to apply a continuous complex hydrological (quantity) model for simulating combined urban and rural runoff processes to a small catchment in Northrhine-Westphalia to get more information on its suitability as a modern planning tool. The study focuses on the general applicability of the method proposed, data availability, the estimation of model parameters, and the reliability of results produced. Another objective was to solve a practical engineering problem with the methodology proposed. The results show that the method can be used to produce a sample of simultaneous overflow/riverflow events, which subsequently can be evaluated statistically. Data availability and computational efforts are suitable for general application.

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