scholarly journals Simulation method for determining traction power of ATN–PRT vehicle

Transport ◽  
2016 ◽  
Vol 33 (2) ◽  
pp. 335-343 ◽  
Author(s):  
Maciej Kozłowski
Keyword(s):  
Aerodynamic Force ◽  
Dynamic Properties ◽  
Simulation Method ◽  
Drive System ◽  
Constant Speed ◽  
Technical Parameters ◽  
Personal Rapid Transit ◽  
Motion Resistance ◽  
The Difference ◽  
Traction Power

The construction of Personal Rapid Transit (PRT) vehicle made within the framework of Eco-Mobility project has been described in the present paper. Key features of the vehicles were identified – e.g. drive with three-phase linear motor with winding on the vehicle and fixed rotor in the road surface, contactless dynamic vehicle powering. Attention was paid to the difference in dynamic properties compared to rail vehicles, related to the lack of the so-called ‘centering mechanism’. A development of a nominal model for the analysis of vehicle drive properties was presented. Results of simulation studies were presented for a vehicle with running-drive system construction, planned for implementation in the city of Rzeszów (Poland). While discussing the problems of building a PRT system, there was a focus on the issue of determining power and traction of the vehicle. A methodology for determining the power and traction energy consumption of the vehicle was presented for assumed conditions of travel on road segments. Input values for the calculation of power are variables describing the curvature (or bends radii) of paths of movement between stops and the course of the current speed. Output values are total traction power or traction energy (where ‘traction’ refers to the power or mechanical work of drive forces). Three basic elements of traction power were isolated: the power of kinetic energy (for acceleration/delay of vehicle movement) basic (to offset the aerodynamic force of motion resistance at constant speed) and additional losses (to offset additional motion resistance forces operating in turns at constant speed). Due to the lack of vehicle prototypes with assumed structure, it was proposed that these components are determined via simulation. The presented results relate to the calculation of demand for power and energy for the planned test section. The scope of further work was indicated: determining the required traction characteristics of electric drive, selecting the best values for supercapacitor’s capacity in the drive system, determining the technical parameters of substation.

scholarly journals Mode Shape-Based Damage Detection Method (MSDI): Experimental Validation

2021 ◽  
Vol 11 (10) ◽  
pp. 4589
Author(s):  
Ivan Duvnjak ◽  
Domagoj Damjanović ◽  
Marko Bartolac ◽  
Ana Skender
Keyword(s):  
Boundary Conditions ◽  
Damage Detection ◽  
Mode Shape ◽  
Experimental Validation ◽  
Detection Method ◽  
Dynamic Properties ◽  
Damage Index ◽  
Main Principle ◽  
The Difference ◽  
Different Levels

The main principle of vibration-based damage detection in structures is to interpret the changes in dynamic properties of the structure as indicators of damage. In this study, the mode shape damage index (MSDI) method was used to identify discrete damages in plate-like structures. This damage index is based on the difference between modified modal displacements in the undamaged and damaged state of the structure. In order to assess the advantages and limitations of the proposed algorithm, we performed experimental modal analysis on a reinforced concrete (RC) plate under 10 different damage cases. The MSDI values were calculated through considering single and/or multiple damage locations, different levels of damage, and boundary conditions. The experimental results confirmed that the MSDI method can be used to detect the existence of damage, identify single and/or multiple damage locations, and estimate damage severity in the case of single discrete damage.

scholarly journals Adaptive Control Structure with Neural Data Processing Applied for Electrical Drive with Elastic Shaft

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3389
Author(s):  
Marcin Kamiński ◽  
Krzysztof Szabat
Keyword(s):  
Neural Network ◽  
Adaptive Control ◽  
Dynamic Properties ◽  
Experimental Studies ◽  
Drive System ◽  
Particle Swarm Optimizer ◽  
The Neural Network ◽  
Control Concept ◽  
Constant Coefficients ◽  
Selection Of

This paper presents issues related to the adaptive control of the drive system with an elastic clutch connecting the main motor and the load machine. Firstly, the problems and the main algorithms often implemented for the mentioned object are analyzed. Then, the control concept based on the RNN (recurrent neural network) for the drive system with the flexible coupling is thoroughly described. For this purpose, an adaptive model inspired by the Elman model is selected, which is related to internal feedback in the neural network. The indicated feature improves the processing of dynamic signals. During the design process, for the selection of constant coefficients of the controller, the PSO (particle swarm optimizer) is applied. Moreover, in order to obtain better dynamic properties and improve work in real conditions, one model based on the ADALINE (adaptive linear neuron) is introduced into the structure. Details of the algorithm used for the weights’ adaptation are presented (including stability analysis) to perform the shaft torque signal filtering. The effectiveness of the proposed approach is examined through simulation and experimental studies.

Inversion of Reservoir Parameters by Ultra-High Temperature and High Pressure CO2 Gas Reservoirs with Nuclear Logging

2021 ◽  
Author(s):  
Hengrong Zhang ◽  
Lizhi Xiao ◽  
Wensheng Wu ◽  
Xinyue Fu ◽  
Shenglin He
Keyword(s):  
Joint Inversion ◽  
Simulation Method ◽  
Inversion Method ◽  
Burial Depth ◽  
Gas Reservoirs ◽  
Co2 Gas ◽  
Carbonate Cement ◽  
Response Equation ◽  
Temperature And Pressure ◽  
The Difference

Abstract The Yinggehai basin is located in the western part of the South China Sea, the burial depth of the Huangliu and Meishan formations in the target layer is close to 4000 meters, the formation temperature is close to 200 degrees Celsius, and the formation pressure is up to 100 MPa. The reservoir is characterized by low porosity-ultra-low permeability, heavy carbonate cement, complex CO2 content, this leads to complex neutron and density logging effects. The solubility of CO2 Above CH4, the solubility change with temperature and pressure is different from CH4, which makes it difficult to identify the CO2 gas layer. In this paper, based on the difference in the physical characteristics of CO2 and CH4, the Boltzmann equation combined with MCNP software was used to simulate the neutron and density logging responses under different CO2 saturations. Environmental factors such as temperature and pressure, carbonate cement, mud content and pores were studied To measure the effect of logging response, the LM inversion method is used to jointly invert CO2 saturation of density and neutron logs. The purpose of the inversion is to reduce the non-uniqueness of the evaluation of porosity and CO2 saturation. By introducing the Levenberg-Marquardt (LM) method, the neutron logging response equation of the porosity, argillaceous content, CO2, CH4 in the rock and the corresponding temperature and pressure is solved, and also the response equation of above parameters to density logging, where porosity and CO2 content are the key parameters, and the calculation results prove the effectiveness of the method by comparing the sampling data. The results show that the accuracy of the estimated CO2 saturation is increased by 10% compared with the conventional interpretation method, and the new simulation method improves the calculation speed several times compared to the MCNP software. The joint inversion method has been successfully applied to field data, which has greatly improved the saturation evaluation results of traditional logging interpretation methods, can be extended to other fields of nuclear logging simulation and inversion.

scholarly journals Characterisation of football trajectories for assessing flight performance

2018 ◽  
Vol 233 (1) ◽  
pp. 16-26
Author(s):  
Matthew Ward ◽  
Martin Passmore ◽  
Adrian Spencer ◽  
Simon Tuplin ◽  
Andy Harland
Keyword(s):  
Aerodynamic Force ◽  
Flight Path ◽  
Force Coefficient ◽  
High Profile ◽  
Inflection Points ◽  
Wide Range ◽  
Identical Manner ◽  
The Difference ◽  
Flight Model ◽  
Mathematical Process

Much discussion surrounds the flight of association footballs (soccer balls), particularly where the flight may be perceived as irregular. This is particularly prevalent in high-profile competitions due to increased camera coverage and public scrutiny. All footballs do not perform in an identical manner in flight. This article develops methods to characterise the important features of flight, enabling direct, quantitative comparisons between ball designs. The system used to generate the flight paths included collection of aerodynamic force coefficient data in a wind tunnel, which were input into a flight model across a wide range of realistic conditions. Parameters were derived from these trajectories to characterise the in-flight deviations across the range of flights from which the aerodynamic performance of different balls were statistically compared. The amount of lateral movement in flight was determined by calculating the final lateral deviation from the initial shot vector. To quantify the overall shape of the flight, increasing orders of polynomial functions were fitted to the flight path until a good fit was obtained with a high-order polynomial indicating a less consistent flight. The number of inflection points in each flight was also recorded to further define the flight path. The orientation dependency of a ball was assessed by comparing the true shot to a second flight path without considering orientation-dependent forces. The difference between these flights isolated the effect of orientation-dependent aerodynamic forces. The article provides the means of quantitatively describing a ball’s aerodynamic behaviour in a defined and robust mathematical process. Conclusions were not drawn regarding which balls are good and bad; these are subjective terms and can only be analysed through comprehensive player perception studies.

scholarly journals Dynamic Analysis and Security Characteristics of Carrier-Based Aircraft Arresting in Yaw Condition

2020 ◽  
Vol 10 (4) ◽  
pp. 1253
Author(s):  
Yiming Peng ◽  
Pengpeng Xie ◽  
Xiaohui Wei ◽  
Hong Nie
Keyword(s):  
Negative Impact ◽  
Early Stage ◽  
Dynamic Properties ◽  
Wave Model ◽  
The United States ◽  
Us Military ◽  
Load Fluctuation ◽  
Kink Wave ◽  
The Difference ◽  
Yaw Angle

In order to research the safety characteristics of carrier-based aircraft in yaw arrest, a complete dynamic model of the arresting system of a certain type of aircraft was developed to understand more about its dynamic properties. Based on the discrete kink-wave model, a simulation of centering arrest was conducted. The simulation results were compared with experimental data from the United States (US) military standards, demonstrating that the basic changing laws are almost the same. On the basis of centering arrest, a simulation of yaw arrest was carried out. The results show that in yaw state, the difference in the lengths of the arresting cables on either side of the hook is smaller in the early stage after the hook hangs on the rope, which leads to little influence on load fluctuation produced by the kink-wave. With the increase in arresting distance, the difference in the lengths of the arresting cables on either side becomes larger, resulting in a situation in which the cable tension on the departure side will gradually become greater than that on the opposite side. In this situation, yaw landing has a negative impact on the characteristics of arresting safety, and the excessive yaw angle causes the aircraft to rush out of the safe landing area.

Determination of Key Technical Parameters of Special Hydraulic Turbine for Cooling Tower

2011 ◽  
Vol 383-390 ◽  
pp. 1386-1390 ◽  
Author(s):  
Yan Pin Li ◽  
Hai Peng Nan ◽  
Kai Chuang Duan
Keyword(s):  
Cooling Tower ◽  
Hydraulic Turbine ◽  
Working Environment ◽  
Pressure System ◽  
Technical Parameters ◽  
Circulating Water ◽  
Power Turbine ◽  
In Series ◽  
The Difference ◽  
Save Energy

The author analyzed the working environment of special hydraulic turbine for cooling tower basing on the difference between the special turbine for cooling tower and the conventional power turbine. The former works in series pressure system and the water head determined by the pipeline resistance and the property of circulating water pump of cooling tower. It is the key to transform the cooling tower system successfully and save energy to build up a series special theories which include the specific speed of turbine for cooling tower, the type of turbine, the parameters selection, the design of the flow passage and runner of turbine by effectively transforming the conventional power turbine theory to the special turbine of cooling tower.

Belt-Drive Mechanics: Energy Losses in the Presence of Detachment Waves

2019 ◽  
Author(s):  
Yingdan Wu ◽  
Michael J. Leamy ◽  
Michael Varenberg
Keyword(s):  
Rolling Friction ◽  
Drive System ◽  
Energy Losses ◽  
Belt Drive ◽  
Interface Shear ◽  
Shear Traction ◽  
Friction Moment ◽  
The Difference ◽  
Contact Arc ◽  
Good Agreement

Abstract The dissipative rolling friction moment in a simple belt-drive system is estimated both experimentally and computationally while taking into account the detachment events at the belt-pulley interface. Shear traction is estimated based on measurements of the shear strain along the contact arc. It is shown that the dissipative moment can be approximated by taking the difference between the shear traction and the load carried by the belt. A model is developed for analyzing the contributions of different components to this dissipative moment by considering both the volumetric and surface hysteresis losses. The computed rolling friction moment is found to be in good agreement with that estimated based on the experiments. It is also found that while the shear- and stretching-induced energy losses contribute the most to the dissipation in the belt drive system, the losses associated with the Schallamach waves of detachment make up a considerable portion of the dissipation in the driver case.

Effects of Ice Thickness on the Aerodynamic Characteristics of Crescent Shape Iced Conductors

2012 ◽  
Vol 166-169 ◽  
pp. 2696-2703 ◽  
Author(s):  
Dong Yan ◽  
Wen Juan Lou ◽  
Ming Feng Huang ◽  
Wei Lin
Keyword(s):  
Lift Force ◽  
Aerodynamic Force ◽  
Wind Tunnel Test ◽  
Aerodynamic Characteristics ◽  
Ice Thickness ◽  
Force Curve ◽  
Force Coefficients ◽  
Variation Patterns ◽  
The Difference ◽  
Force Characteristics

Aerodynamic characteristics of iced conductors were investigated by the wind tunnel test. Under the homogeneous turbulence of 5% intensity, aerodynamic force coefficients of single and bundled conductors were obtained at wind angles of 0°~180°. The variation patterns of aerodynamic forces on the iced conductors with respect to wind angels of attack were systematically studied for the ice thickness of 0.25, 0.5, 0.75 and 1 times of the conductor diameter. The difference of aerodynamic force characteristics for single and bundled conductors were identified and discussed. Based on the Den Hartog and Nigol’s mechanisms of galloping, the wind angle ranges sensitive to galloping were analyzed. The results show that lift and torsion force coefficients reach peak values at wind angles of 15°~20°. For bundled conductors, lift force curve is approximately agreed with the curve of single conductor. Drag force coefficients were smaller than these of single conductor at some wind angles. There are noticeably differences of torsion coefficients existed between bundled conductors and single conductor. According to two classical galloping mechanisms, wind angles of 15°~30°are critical for the galloping of iced conductors with crescent shapes.

Evaluation of a corrected implementation of a method of simulating pulmonary nodules in chest tomosynthesis

2016 ◽  
Vol 58 (4) ◽  
pp. 408-413 ◽  
Author(s):  
Frida Svensson ◽  
Christina Söderman ◽  
Angelica Svalkvist ◽  
Rauni Rossi Norrlund ◽  
Jenny Vikgren ◽  
...  
Keyword(s):  
Receiver Operating Characteristic ◽  
Detection Rate ◽  
Operating Characteristic ◽  
Area Under The Curve ◽  
Pulmonary Nodules ◽  
Simulation Method ◽  
Computer Code ◽  
Anatomical Location ◽  
Visual Appearance ◽  
The Difference

Background A method of simulating pulmonary nodules in tomosynthesis images has previously been developed and evaluated. An unknown feature of a rounding function included in the computer code was later found to introduce an artifact, affecting simulated nodules in low-signal regions of the images. The computer code has now been corrected. Purpose To perform a thorough evaluation of the corrected nodule-simulation method, comparing the detection rate and visual appearance of artificial nodules with those of real nodules in an observer performance experiment. Material and Methods A cohort of 64 patients with a total of 129 pulmonary nodules was used in the study. Artificial nodules, each matching a corresponding real nodule by size, attenuation, and anatomical location, were generated and simulated into the tomosynthesis images of the different patients. The detection rate and visual appearance of artificial nodules generated using both the corrected and uncorrected computer code were compared to those of real nodules. The results were evaluated using modified receiver operating characteristic (ROC) analyses. Results The difference in detection rate between artificial and real nodules slightly increased using the corrected computer code (uncorrected code: area under the curve [AUC], 0.47; 95% CI, 0.43–0.51; corrected code: AUC, 0.42; 95% CI, 0.38–0.46). The visual appearance was however substantially improved using the corrected computer code (uncorrected code: AUC, 0.70; 95% CI, 0.63–0.76; corrected code: AUC, 0.49; 95% CI, 0.29–0.65). Conclusion The computer code including a correct rounding function generates simulated nodules that are more visually realistic than simulated nodules generated using the uncorrected computer code, but have a slightly different detection rate compared to real nodules.

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