Computer-Aided Wheel Profile Design for Railway Vehicles

1989 ◽  
Vol 111 (3) ◽  
pp. 288-291 ◽  
Author(s):  
Imtiaz-ul-Haque ◽  
D. A. Latimer ◽  
E. H. Law
Keyword(s):  
Nonlinear Programming ◽  
Dynamic Performance ◽  
Optimization Methods ◽  
Theoretical Studies ◽  
Interaction Forces ◽  
Rail Vehicles ◽  
Computer Aided ◽  
Wheel Profile ◽  
Profile Design ◽  
Conventional Rail

Wheel-rail geometry parameters strongly affect the dynamic performance of rail vehicles through their influence on the interaction forces between the wheel and rail. This paper presents an approach that uses nonlinear programming and optimization methods to systematically design wheel profiles that satisfy dynamic performance and wear constraints for conventional rail vehicles. Theoretical studies conducted to this point indicate this approach to be feasible.

Effects of Independently Rolling Wheels on Flange Climb Derailment

2004 ◽  
Author(s):  
Nicholas Wilson ◽  
Xinggao Shu ◽  
Ken Kramp
Keyword(s):  
Dynamic Modeling ◽  
Light Rail ◽  
Technology Center ◽  
Rail Vehicles ◽  
Modeling Software ◽  
Wheel Profile ◽  
Profile Design ◽  
Flange Angle

The effects of independently rolling wheels (IRW) on flange climb derailment have been investigated through simulations using Transportation Technology Center, Inc. (TTCI)’s *NUCARSTM dynamic modeling software. Simulations of single wheelsets and hypothetcal light rail vehicles equipped with IRWs show that flange angle and flange length parameters play an important role in preventing derailments. That role is especially critical for independent rolling wheels due to their lack of self-steering capability. The speed contour concept was proposed for engineers to adopt the flange angle and flange length in a logical way for wheel profile design in new vehicles and wheel profile maintenance. It is also shown that the sensitivity of IRW to flange climb is also very dependent on particular vehicle designs.

A design method for rail profiles based on the geometric characteristics of wheel–rail contact

2017 ◽  
Vol 232 (5) ◽  
pp. 1255-1265 ◽  
Author(s):  
Xin Mao ◽  
Gang Shen
Keyword(s):  
Contact Angle ◽  
Design Method ◽  
Dynamic Performance ◽  
Solution Process ◽  
Main Design ◽  
Rail Vehicles ◽  
Angle Difference ◽  
Wheel Profile ◽  
Contact Distribution ◽  
The Given

Designing a proper rail profile carries more significance than designing a wheel profile because of the amount of work and cost involved in the maintenance of rails. A better rail profile will not only help to ensure achieving the desired dynamic performance of rail vehicles but it also extends the service life of rails. This paper presents a unique design method for the design of rail profiles based on the given geometric contact characteristics. The proposed method utilizes a given wheel profile and two typical functions respectively to set the main design targets. The first function is the rolling radii difference and the second one is the contact angle difference. Wheel–rail contact distribution is chosen as the secondary target to prevent stress concentration and the associated fatigue failure. With certain assumptions, the solution process becomes a reverse designed one, which can be solved by using proper discrete numerical methods. Two examples of rail profile designs have been discussed in detail for rigid and independent wheelsets.

Magnetic Guidance of Conventional Railroad Vehicles

1982 ◽  
Vol 104 (3) ◽  
pp. 238-246 ◽  
Author(s):  
R. J. Caudill ◽  
L. M. Sweet ◽  
K. Oda
Keyword(s):  
High Speed ◽  
Dynamic Performance ◽  
Ride Quality ◽  
Normal Forces ◽  
Rail Vehicles ◽  
Magnetic Guidance ◽  
Curving Performance ◽  
Near Term ◽  
Conventional Rail ◽  
Derailment Safety

The potential for improved dynamic performance of conventional rail vehicles through control of linear induction or synchronous motors is explored. Improvements in vehicle stability, ride quality, traction capability, track loading, derailment safety, and curving performance result from use of controllable lateral and normal forces present in the motor. Recent advances in technology originally developed for high-speed levitated vehicles are applied to conventional railroad systems which have a greater potential for near-term implementation. The dynamic performance of alternate configurations, consisting of several generic motor types mounted either on trucks or carbodies, are evaluated. Significant improvements in both lateral dynamic stability and curving performance may be realized through magnetic guidance of the trucks using force levels well within the capability of existing linear motor technology.

scholarly journals A Comprehensive Review of Isogeometric Topology Optimization: Methods, Applications and Prospects

2020 ◽  
Vol 33 (1) ◽  
Author(s):  
Jie Gao ◽  
Mi Xiao ◽  
Yan Zhang ◽  
Liang Gao
Keyword(s):  
Topology Optimization ◽  
Computer Aided Design ◽  
Numerical Technique ◽  
Optimization Methods ◽  
Negative Influence ◽  
Comprehensive Overview ◽  
Promising Alternative ◽  
Computer Aided ◽  
Optimal Material ◽  
Material Layout

AbstractTopology Optimization (TO) is a powerful numerical technique to determine the optimal material layout in a design domain, which has accepted considerable developments in recent years. The classic Finite Element Method (FEM) is applied to compute the unknown structural responses in TO. However, several numerical deficiencies of the FEM significantly influence the effectiveness and efficiency of TO. In order to eliminate the negative influence of the FEM on TO, IsoGeometric Analysis (IGA) has become a promising alternative due to its unique feature that the Computer-Aided Design (CAD) model and Computer-Aided Engineering (CAE) model can be unified into a same mathematical model. In the paper, the main intention is to provide a comprehensive overview for the developments of Isogeometric Topology Optimization (ITO) in methods and applications. Finally, some prospects for the developments of ITO in the future are also presented.

Comparison between Optimization Method and Experience-Based Method in Soil Conservation

2013 ◽  
Vol 726-731 ◽  
pp. 3811-3817
Author(s):  
Yuan Feng ◽  
Ji Xian Wang
Keyword(s):  
Slope Stability ◽  
Soil Conservation ◽  
Computer Aided Design ◽  
Optimization Methods ◽  
Optimization Method ◽  
Interaction Function ◽  
The Standard Model ◽  
Computer Aided ◽  
Slice Method ◽  
Aided Design

The analysis of the slope stability is important in soil conservation. To analyze the slope stability, optimization methods were coded and compared with the traditional experience-based methods. Furthermore, the results were visualized in the program, so that the user can easily check the results and can designate an area, in which the program seeks the center and radius of the most hazardous slide arc. Moreover, the graphic interaction function was implemented in the program. In addition, the Standard Model One, recommended by ACAD (The Association for Computer Aided Design), was calculated by the program, of which the results (safety factor Ks=0.95~0.96) were smaller than the official recommend value (Ks=1). It is because that the traditional slice method, which neglects the normal stress and shear stress between the slices, was applied for calculation of Ks.

Gradient-Free Optimization in Thermoacoustics: Application to A Low-Order Model

2021 ◽  
Author(s):  
Johann Moritz Reumschüssel ◽  
Jakob G. R. von Saldern ◽  
Yiqing Li ◽  
Christian Oliver Paschereit ◽  
Alessandro Orchini
Keyword(s):  
Optimization Algorithms ◽  
Optimization Methods ◽  
Theoretical Studies ◽  
Order Model ◽  
Output Data ◽  
Fuel Injectors ◽  
Solution Strategies ◽  
The Past ◽  
Downhill Simplex ◽  
Low Order

Abstract Machine learning and automatized routines for parameter optimization have experienced a surge in development in the past years, mostly caused by the increasing availability of computing capacity. Gradient-free optimization can avoid cumbersome theoretical studies as input parameters are purely adapted based on output data. As no knowledge about the objective function is provided to the algorithms, this approach might reveal unconventional solutions to complex problems that were out of scope of classical solution strategies. In this study, the potential of these optimization methods on thermoacoustic problems is examined. The optimization algorithms are applied to a generic low-order thermoacoustic can-combustor model with several fuel injectors at different locations. We use three optimization algorithms — the well established Downhill Simplex Method, the recently proposed Explorative Gradient Method, and an evolutionary algorithm — to find optimal fuel distributions across the fuel lines while maintaining the amount of consumed fuel constant. The objective is to have minimal pulsation amplitudes. We compare the results and efficiency of the gradient-free algorithms. Additionally, we employ model-based linear stability analysis to calculate the growth rates of the dominant thermoacoustic modes. This allows us to highlight general and thermoacoustic-specific features of the optimization methods and results. The findings of this study show the potential of gradient-free optimization methods on combustor design for tackling thermoacoustic problems, and motivate further research in this direction.

An energy-efficient scalar control taking core losses into account

2018 ◽  
Vol 37 (2) ◽  
pp. 849-867 ◽  
Author(s):  
Gabriel Khoury ◽  
Ragi Ghosn ◽  
Flavia Khatounian ◽  
Maurice Fadel ◽  
Mathias Tientcheu
Keyword(s):  
Energy Efficient ◽  
Mechanical Load ◽  
Dynamic Performance ◽  
Optimization Technique ◽  
Optimization Methods ◽  
Variable Speed ◽  
Variable Speed Drives ◽  
Content Type ◽  
Scalar Control ◽  
Core Losses

PurposeIn the need to optimize the energy efficiency, control structures can have a positive effect by tracking the optimal operating point according to the speed and mechanical load of the motor. The purpose of this paper is to present an energy-efficient scalar control for squirrel-cage induction motors (IMs), taking into consideration the effect of core losses. Design/methodology/approachThe proposed technique is based on the modification of the stator flux reference, to track the best efficiency point. The optimal flux values are computed through an improved model of the IM including core losses, then stored in a look-up table. FindingsSimulations of the proposed scalar control are carried out, and results show the efficiency improvement when the flux is optimized especially at low load cases. Results were validated experimentally on two motors compliant with different efficiency standards. Practical implicationsThe proposed approach can be used in several fields and applications using the scalar-controlled IM with a proper implementation in variable speed drives, as in the cases of pumps, compressors and blowers. Originality/valueThe proposed technique is compared to existing optimization methods in literature, and the results show an improvement in the dynamic performance and in the response delays. The approach is also compared to an optimization technique used in industries like Leroy-Somer for variable speed drives, and efficiency improvements are shown.

A Computer-Aided Design Technique for the Synthesis of Planar Four Bar Mechanisms Satisfying Specified Kinematic and Dynamic Conditions

1987 ◽  
Author(s):  
G. A. Rigelman ◽  
S. N. Kramer
Keyword(s):  
Computer Aided Design ◽  
Dynamic Performance ◽  
Mathematical Formulation ◽  
Average Power ◽  
Optimization Method ◽  
Dynamic Conditions ◽  
Allowable Deviation ◽  
Computer Aided ◽  
Precision Synthesis ◽  
Aided Design

Abstract This paper presents a computer-aided design optimization method for synthesizing planar four bar mechanisms which satisfy specified kinematic and dynamic conditions. The method can be used for path, motion, and function generation as well as for combinations of these. The kinematic conditions consist of combinations of specifications on the position, velocity, and acceleration of the coupler point and the rotations of the coupler and follower links. The dynamic conditions consist of the minimization of the average power consumed by the mechanism as well as a limit on the maximum input torque. The external loads consist of variable forces and moments at the coupler point as well as variable torques on the follower link. The Selective Precision Synthesis (SPS) method is used to express each kinematic condition in terms of a specification plus an allowable deviation or tolerance from the specification. In this manner, the synthesis problem is converted into a nonlinear optimization problem which is solved by using the Generalized Reduced Gradient (GRG) method. In addition, two force balancing routines are included to help the dynamic performance of the mechanism. The mathematical formulation and derivation as well as numerical examples are presented in this paper.

scholarly journals Computer-Aided Design of Microfluidic Circuits

2020 ◽  
Vol 22 (1) ◽  
pp. 285-307 ◽  
Author(s):  
Elishai Ezra Tsur
Keyword(s):  
Computer Aided Design ◽  
Integrated Design ◽  
Optimization Methods ◽  
Performance Requirements ◽  
Computer Aided ◽  
Paper Based Microfluidics ◽  
Specification Synthesis ◽  
Description Languages ◽  
Aided Design

Microfluidic devices developed over the past decade feature greater intricacy, increased performance requirements, new materials, and innovative fabrication methods. Consequentially, new algorithmic and design approaches have been developed to introduce optimization and computer-aided design to microfluidic circuits: from conceptualization to specification, synthesis, realization, and refinement. The field includes the development of new description languages, optimization methods, benchmarks, and integrated design tools. Here, recent advancements are reviewed in the computer-aided design of flow-, droplet-, and paper-based microfluidics. A case study of the design of resistive microfluidic networks is discussed in detail. The review concludes with perspectives on the future of computer-aided microfluidics design, including the introduction of cloud computing, machine learning, new ideation processes, and hybrid optimization.

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