scholarly journals Analysis and Optimization of Driving Attitude and Oscillation Characteristics of Suspension-Type Small Rail Vehicles

2020 ◽  
Vol 2020 ◽  
pp. 1-21
Author(s):  
Bing Liu ◽  
Huijun Yue ◽  
Jiachun Lin ◽  
Xiangkai Wu ◽  
Zhaoyao Shi
Keyword(s):  
Simulation Model ◽  
High Efficiency ◽  
Ride Comfort ◽  
Center Of Mass ◽  
Lateral Velocity ◽  
Transit Systems ◽  
Object A ◽  
Personal Rapid Transit ◽  
Rail Vehicles ◽  
Attitude Angle

Suspension-type small rail personal rapid transit systems are widely concerned due to their high efficiency and reliability. The increasing demands for ride comfort have put forward higher requirements for vehicle stationarity. In the study, with a single-bogie vehicle as the research object, a dynamic equation and a simulation model are firstly established to calculate the attitude angle and lateral velocity of the vehicle. Then, with the small amplitude and fast attenuation of the attitude angle and lateral velocity in a straight line and a bend as optimization objectives, the simulation model is optimized in terms of a series of variables, including the bogie with or without the supporting wheel, the supporting wheel tread, the driving wheel tread, the guide wheel tread, and the changes of the center of mass of the vehicle. Then, the problem of severe vehicle pitch with the double-bogie structure is solved. Finally, the simulation results and the optimization scheme are experimentally verified. The above optimization measures can significantly improve the driving stationarity of suspension-type small rail vehicles and enhance ride comfort.

Research on springback characteristic in flexible multi-points 3D stretch-bending process

2021 ◽  
pp. 095440542110284
Author(s):  
Song Gao ◽  
Tonggui He ◽  
Qihan Li ◽  
Yingli Sun ◽  
Jicai Liang
Keyword(s):  
Simulation Model ◽  
High Efficiency ◽  
Vertical Direction ◽  
Factors Affecting ◽  
Stretch Bending ◽  
Element Simulation ◽  
Bending Process ◽  
Bending Radius ◽  
Aluminum Profiles ◽  
Bending Sequence

The problem of springback is one of the most significant factors affecting the forming accuracy for aluminum 3D stretch-bending parts. In order to achieve high-efficiency and high-quality forming of such kind of structural components, the springback behaviors of the AA6082 aluminum profiles are investigated based on the flexible multi-points 3D stretch-bending process (3D FSB). Firstly, a finite element simulation model for the 3D FSB process was developed to analyze the forming procedure and the springback procedure. The forming experiments were carried out for the rectangle-section profile to verify the effectiveness of the simulation model. Secondly, the influence of tension on springback was studied, which include the pre-stretching and the post-stretching. Furthermore, the influences of the bending radius and bending sequence are revealed. The results show that: (1) The numerical model can be used to evaluate the effects of bending radius and process parameters on springback in the 3D FSB process effectively. (2) The pre-stretching has little effect on the horizontal springback reduction, but it plays a prominent role in reducing the springback in the vertical direction. (3) The increase of bending deformation in any direction will lead to an increase of springback in its direction and reduce the springback in the other direction. Besides, it reduces the relative error in both directions simultaneously. This research established a foundation to achieve the precise forming of the 3D stretch-bending parts with closed symmetrical cross-section.

Research on Throttle Optimal Control of Flipper Jack for Hydraulic Support

2012 ◽  
Vol 503-504 ◽  
pp. 824-827
Author(s):  
Chun Qiang Jia ◽  
Wei Li ◽  
Ling Yu
Keyword(s):  
Optimal Control ◽  
Simulation Model ◽  
High Efficiency ◽  
Hydraulic Support ◽  
Simulation Results ◽  
Amesim Simulation

To solve the problem of support speed of hydraulic support flipper, the match relations between the flipper throttle control and shearer cutting coal speed are analyzed, the AMESim simulation model of the throttle optimal control for hydraulic support flipper jack is established, the simulation results show that flipper can be supported timely by speed optimal control of flipper jack which improve the reliability of the system and provide certain theory basis to meet the miner safety and high efficiency production.

Multivariate Constrained GNSS Real-time Full Attitude Determination Based on Attitude Domain Search

2018 ◽  
Vol 72 (2) ◽  
pp. 483-502
Author(s):  
Hongtao Wu ◽  
Xiubin Zhao ◽  
Chunlei Pang ◽  
Liang Zhang ◽  
Bo Feng
Keyword(s):  
Objective Function ◽  
Success Rate ◽  
High Efficiency ◽  
Attitude Determination ◽  
A Priori ◽  
Three Dimensional ◽  
Satellite System ◽  
New Method ◽  
Lambda Method ◽  
Attitude Angle

A priori attitude information can improve the success rate and reliability of Global Navigation Satellite System (GNSS) multi-antennae attitude determination. However, a priori attitude information is nonlinear, and integrating a priori information into the objective function rigorously will increase the complexity of an ambiguity domain search, such as the Multivariate Constrained-Least-squares Ambiguity Decorrelation Adjustment (MC-LAMBDA) method. In this paper, a new method based on attitude domain search is presented to make use of the a priori attitude angle information with high efficiency. First, the a priori information of pitch and roll is integrated into the search process to derive the analytic search step for attitude angle, and the integer candidates are determined by traversal search in the three-dimensional attitude domain. Then, the objective function is parameterised with Euler angles, and a non-iterative approximate method is utilised to simplify the iterative computation in calculating objective function values. Experimental results reveal that compared to the MC-LAMBDA method, our new method has the same success rate and reliability, but higher efficiency in making use of a priori attitude information.

scholarly journals Safety in residential buildings: Evacuation from residential buildings without fire escape stairs

2021 ◽  
Vol 69 (1) ◽  
pp. 148-178
Author(s):  
Radoje Jevtić
Keyword(s):  
Simulation Model ◽  
Residential Buildings ◽  
Residential Building ◽  
Simulation Software ◽  
Modeling Method ◽  
Real Object ◽  
Object A ◽  
The Third

Introduction/purpose: Safety in high residential buildings presents a very important and always actual task. In case of some unforeseen and dangerous occurrences, their residents must be evacuated. Fire, earthquakes, and terrorism are only some of such situations. The speed of evacuation from high residential buildings depends on many different factors. A particularly difficult and complex evacuation task concerns buildings without fire escape stairs. Methods: The modeling method was used in this paper. Based on a real object - a residential building, an appropriate simulation model was realized in appropriate simulation software. Results: The results of this paper have shown that, out of four scenarios, the fastest evacuation was for the evacuation speed of 1.75 m/s. The first two scenarios did not report any jams, unlike the third and fourth scenario; in the third scenario, the occupants' speeds were 0.75 m/s and 1.25 m/s while in the fourth scenario, the simulated occupants' speeds were from 0.75 m/s to 1.75 m/s. Conclusion:The usage of appropriate simulation software enables fast, precise, safe and cheap calculation of evacuation times and it can significantly improve evacuation procedures and evacuation strategies.

scholarly journals SIMULATION MODELING OF INVOLUNTARY HUMAN MOVEMENTS

2019 ◽  
pp. 67-76
Author(s):  
Д.В. Горбунов ◽  
Т.В. Гавриленко
Keyword(s):  
Simulation Model ◽  
Simulation Modeling ◽  
High Efficiency ◽  
Three Dimensional ◽  
Neuromuscular System ◽  
Three Dimensional Modeling ◽  
Dimensional Modeling ◽  
Human Movements ◽  
Human Limb ◽  
Model Algorithm

Разработана математическая и симуляционная модель для моделирования биомеханических движений конечности человека. Разработанный алгоритм модели базируется на биологическом представлении о включении и выключении в процессе удержания положения конечности отдельных мышц или их групп. Работа модели осуществляется за счет генерации случайных чисел (в математической форме симмуляционной модели отсутствуют статические величины). Сравнительный анализ экспериментальных и модельных данных показывает высокую эффективность работы симуляционной модели. Созданная симуляционная модель позволяет изучать принципы работы нервно-мышечной системы. Также модель является масштабируемой, что позволит в дальнейшем перейти к трехмерному моделированию для изучения механизмов самоорганизации биосистемы на уровне и нервно-мышечной системы, и центральной нервной системы. Mathematical and simulation model has been developed for modeling the biomechanical movements of a human limb. The developed model algorithm is based on the biological presentation and shutdown in the process of maintaining the positions of the final individual muscles or their groups. Work in models is due to statistical values. A comparative analysis of experimental and model data shows the high efficiency of the simulation model. The created simulation model allows to study the principles of the neuromuscular system. This model is scalable, which will allow us to switch to three-dimensional modeling to study the signs of self-organization of biosystems at the level of the neuromuscular system and central nervous system.

scholarly journals Assessment of a rail vehicle running with the damaged wheel on a ride comfort for passengers

2018 ◽  
Vol 157 ◽  
pp. 03004 ◽  
Author(s):  
Ján Dižo ◽  
Miroslav Blatnický ◽  
Stasys Steišūnas ◽  
Blanka Skočilasová
Keyword(s):  
Ride Comfort ◽  
Railway Wheel ◽  
Rail Vehicle ◽  
Rail Vehicles ◽  
Dynamic Analyses ◽  
Wheel Flat

In certain conditions rail vehicles wheels can be during operation damaged. Then, the profile of wheels is no longer circular, but it is changed depending on the type and severity of defects. When such rail vehicle with the damaged wheel operates, the quality of a ride comfort for passenger is degraded. This article is focused on the assessment of ride comfort for passenger based on results obtained from dynamic analyses. Simulations and calculations were carried out in commercial multibody software. In our research we considered one type of the railway wheel untrueness – wheel-flat. This type of wheel damaging is relatively common and has such influence on the ride comfort for passenger worsening, which needs to be detected and investigated.

Using Full Scale Experiments to Verify a Simulation Used to Analyze the Safety of Rail Vehicles During Large Earthquakes

2015 ◽  
Vol 10 (3) ◽  
Author(s):  
Kazuhiko Nishimura ◽  
Yoshiaki Terumichi ◽  
Tsutomu Morimura ◽  
Masahito Adachi ◽  
Yoshitaka Morishita ◽  
...  
Keyword(s):  
Simulation Model ◽  
Dynamic Interaction ◽  
Full Scale ◽  
Vehicle Speed ◽  
Full Scale Test ◽  
Rail Vehicles ◽  
Rocking Motion ◽  
Scale Test ◽  
Large Earthquakes ◽  
Full Scale Testing

A simulation model is used to calculate the rocking motion of a vehicle and how antiderailing guard rails work to prevent derailment when subject to large ground excitation and the results are verified through full scale testing. (1) The simple vehicle–track model should properly represent the rocking mechanism. (2) The effect of vehicle speed on the wheel/rail slide is also properly represented, thus the wheel/rail creep law model can be applied to the analysis of a running vehicle experiencing large rocking motion. (3) The action of the guard rail was equal in both the simulation and the full scale test, thus indicating that the simple antiderailing guard rail model sufficiently represents the dynamic interaction of the wheel/guard rail and the effect.

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