Download or read book Improving the Performance of Finite Element Simulations on the Wheel rail Interaction by Using a Coupling Strategy written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past few years, a number of implicit/explicit finite element models have been introduced for the purpose of tackling the problems of wheel–rail interaction. Yet, most of those finite element models encounter common numerical difficulties. For instance, initial gaps/penetrations between two contact bodies, which easily occur when realistic wheel–rail profiles are accounted for, would trigger the problems of divergence in implicit finite element simulations. Also, redundant, insufficient or mismatched mesh refinements in the vicinity of areas in contact can lead to either prohibitive calculation expenses or inaccurate implicit/explicit finite element solutions. To address the abovementioned problems and to improve the performance of finite element simulations, a novel modelling strategy has been proposed. In this strategy, the three-dimensional explicit finite element analysis is seamlessly coupled with the two-dimensional geometrical contact analysis. The contact properties in the three-dimensional finite element analyses, such as the initial “Just-in-contact” point, the exact wheel local rolling radius, etc., which are usually a priori unknown, are determined using the two-dimensional geometrical contact model. As part of the coupling strategy, a technique has been developed for adaptive mesh refinement. The mesh and mesh density of wheel–rail finite element models change adaptively depending on the exact location of the contact areas and the local geometry of contact bodies. By this means, a good balance between the calculation efficiency and accuracy can be achieved. Last, but not least, the advantage of the coupling strategy has been demonstrated in studies on the relationship between the initial slips and the steady frictional rolling state. Finally, the results of the simulations are presented and discussed.

Download or read book Finite Element Analysis of Vibration Excited by Rail Wheel Interaction written by Yun Zhan and published by . This book was released on 2017-01-26 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "Finite Element Analysis of Vibration Excited by Rail-wheel Interaction" by Yun, Zhan, 詹云, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: In previous attempts reported in the open literature on modelling rail/wheel dynamics, beam theories are commonly employed to model the rail and rail-wheel contact can be considered by linear or nonlinear contact springs. As the contact force is expected to have a strong influence on the rail corrugation, the predicted contact force is often the key interest. It is noted to be a rather smooth function of time and is different from, for instance, the rail acceleration which contains a considerable amount of high frequency content. On the other hand, finite element method has evolved into a widely accepted numerical simulation tool for engineering analysis. Despite its applicability to many physical phenomena, three-dimensional finite element simulation of rail-wheel dynamic interaction remains to be a computationally formidable task due to the minute size of the rail-wheel instantaneous contact zone. In this thesis, a beam and a plane finite element models are constructed to examine the rail-wheel dynamic interaction. The beam finite element model composes of two-dimensional Timoshenko beam elements whilst contact is mimicked by using a nonlinear contact spring. On the other hand, the plane finite element model composes of plane elements. While very small elements are used on the contacting surfaces, i.e. the wheel rim and rail top, the element size away from the surfaces is kept large in order to reduce the number of elements. To transit the mesh from dense to coarse, different transition meshes are examined and the one showing the best accuracy is employed. Meanwhile, two different ways of simulated contact are examined. The chosen method of kinematic constraint can deliver a reasonable accuracy and, unlike the penalty method, would not reduce the critical time increment in explicit time integration. The contact forces predicted by the beam and plane finite element models are compared. It is noted that the trends of the contact forces predicted by two finite element models show good agreements with each other. However, the plane finite element model has several advantages in the simulations of rail/wheel dynamics over the beam finite element model. The effects of high wheel speed and multiple rolling wheels on rail/wheel dynamics are investigated. It is found that both the high wheel speed and multiple rolling wheels on a rail lead to more severe rail vibrations. Owing to its advantages in the simulations of rail/wheel dynamics, the plane finite element model is then applied to examine the damping capacities of tuned mass damper which is a promising means for reducing the rail vibration. The predicted rail acceleration reveals that the rail vibration can be attenuated considerably when the tuned mass damper is installed. DOI: 10.5353/th_b5351000 Subjects: Railroad cars - Dynamics - Mathematics

Download or read book Vehicle Track Coupled Dynamics written by Wanming Zhai and published by Springer Nature. This book was released on 2019-08-31 with total page 417 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book systematically presents the theory, numerical implementation, field experiments and practical engineering applications of the ‘Vehicle–Track Coupled Dynamics’. Representing a radical departure from classic vehicle system dynamics and track dynamics, the vehicle–track coupled dynamics theory considers the vehicle and track as one interactive and integrated system coupled through wheel–rail interaction. This new theory enables a more comprehensive and accurate solution to the train–track dynamic interaction problem which is a fundamental and important research topic in railway transportation system, especially for the rapidly developed high-speed and heavy-haul railways. It has been widely applied in practical railway engineering. Dr. Wanming Zhai is a Chair Professor of Railway Engineering at Southwest Jiaotong University, where he is also chairman of the Academic Committee and Director of the Train and Track Research Institute. He is a member of the Chinese Academy of Sciences and one of the leading scientists in railway system dynamics. Professor Zhai is Editor-in-Chief of both the International Journal of Rail Transportation, published by Taylor & Francis Group, and the Journal of Modern Transportation, published by Springer. In addition, he is a trustee of the International Association for Vehicle System Dynamics, Vice President of the Chinese Society of Theoretical and Applied Mechanics, and Vice President of the Chinese Society for Vibration Engineering. /div

Download or read book Vehicle bridge Interaction Dynamics written by Yeong-Bin Yang and published by World Scientific. This book was released on 2004 with total page 565 pages. Available in PDF, EPUB and Kindle. Book excerpt: The commercial operation of the bullet train in 1964 in Japan marked the beginning of a new era for high-speed railways. Because of the huge amount of kinetic energy carried at high speeds, a train may interact significantly with the bridge and even resonate with it under certain circumstances. Equally important is the riding comfort of the train cars, which relates closely to the maneuverability of the train during its passage over the bridge at high speeds.This book is unique in that it is devoted entirely to the interaction between the supporting bridges and moving trains, the so-called vehicle-bridge interaction (VBI). Finite element procedures have been developed to treat interaction problems of various complexities, while the analytical solutions established for some typical problems are helpful for identifying the key parameters involved. Besides, some field tests were conducted to verify the theories established.This book provides an up-to-date coverage of research conducted on various aspects of the VBI problems. Using the series of VBI elements derived, the authors study a number of frontier problems, including the impact response of bridges with elastic bearings, the dynamic response of curved beam to moving centrifugal forces, the stability and derailment of trains moving over bridges shaken by earthquakes, the impact response of two trains crossing on a bridge, the steady-state response of trains moving over elevated bridges, and so on.

Download or read book Finite Element Analysis of Sucker Rod Couplings with Guidelines for Improving Fatigue Life written by and published by . This book was released on 1997 with total page 65 pages. Available in PDF, EPUB and Kindle. Book excerpt: The response of a variety of sucker rod couplings to an applied axial load was simulated using axisymmetric finite element models. The calculations investigated three sucker rod sizes and various combinations of the slimhole, Spiralock, and Flexbar modifications to the coupling. In addition, the effect of various make-ups (assembly tightness) on the performance of coupling was investigated. An axial load was applied to the sucker rod ranging from -5 ksi to 40 ksi, encompassing three load cycles identified on a modified Goodman diagram as acceptable for indefinite service life of the sucker rods. The simulations of the various coupling geometries and make-ups were evaluated with respect to how well they accomplish the two primary objectives of preloading threaded couplings: (1) to lock the threaded coupling together so that it will not loosen and eventually uncouple, and (2) to improve the fatigue resistance of the threaded connection by reducing the stress amplitude in the coupling when subjected to cyclic loading. Perhaps the most significant finding in this study was the characterization of the coupling parameters which affect two stress measures. The mean hydrostatic stress, which determines the permissible effective alternating stress, is a function of the coupling make-up. Whereas, the alternating effective stress is a function of the relative stiffnesses of the pin and box sections of the coupling and, as long as the coupling does not separate, is unaffected by the amount of circumferential displacement applied during make-up. The results of this study suggest approaches for improving the fatigue resistance of sucker rod couplings.

Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1989 with total page 410 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dissertation Abstracts International written by and published by . This book was released on 2001 with total page 810 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book 2D FE DEM Analysis of Tractive Performance of an Elastic Wheel for Planetary Rovers written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Highlights: 2D FE–DEM was applied to tractive performance analysis of an elastic wheel. Earlier code was updated by introducing a PID-controller model. Two-wheel traction analysis result curves matched those of experimental results. FE–DEM results for Mars show similar traction for wheels with different rigidity. Abstract: We have been developing a simulation program for use with soil–wheel interaction problems by coupling Finite Element Method (FEM) and Discrete Element Method (DEM) for which a wheel is modeled by FEM and soil is expressed by DEM. Previous two-dimensional FE–DEM was updated to analyze the tractive performance of a flexible elastic wheel by introducing a new algorithm learned from the PID-controller model. In an elastic wheel model, four structural parts were defined using FEM: the wheel rim, intermediate part, surface layer, and wheel lugs. The wheel rigidity was controlled by varying the Young's Modulus of the intermediate part. The tractive performance of two elastic wheels with lugs for planetary rovers of the European Space Agency was analyzed. Numerical results were compared with experimentally obtained results collected at DLR Bremen, Germany. The FE–DEM result was confirmed to depict similar behaviors of tractive performance such as gross tractive effort, net traction, running resistance, and wheel sinkage, as in the results of experiments. Moreover, the tractive performance of elastic wheels on Mars was predicted using FE–DEM. Results clarified that no significant difference of net traction exists between the two wheels.

Download or read book Bridge Vibration and Controls written by H. Xia and published by Nova Science Publishers. This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Includes bibliographical references and index.

Download or read book Annual Index abstracts of SAE Technical Papers written by and published by . This book was released on 2007 with total page 1218 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Design and Simulation of Heavy Haul Locomotives and Trains written by Maksym Spiryagin and published by CRC Press. This book was released on 2016-10-03 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the increasing demands for safer freight trains operating with higher speed and higher loads, it is necessary to implement methods for controlling longer, heavier trains. This requires a full understanding of the factors that affect their dynamic performance. Simulation techniques allow proposed innovations to be optimised before introducing them into the operational railway environment. Coverage is given to the various types of locomotives used with heavy haul freight trains, along with the various possible configurations of those trains. This book serves as an introductory text for college students, and as a reference for engineers practicing in heavy haul rail network design,

Download or read book Wheel Rail Interface Handbook written by R. Lewis and published by Elsevier. This book was released on 2009-09-25 with total page 865 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many of the engineering problems of particular importance to railways arise at interfaces and the safety-critical role of the wheel/rail interface is widely acknowledged. Better understanding of wheel/rail interfaces is therefore critical to improving the capacity, reliability and safety of the railway system.Wheel-rail interface handbook is a one-stop reference for railway engineering practitioners and academic researchers. Part one provides the fundamentals of contact mechanics, wear, fatigue and lubrication as well as state-of-the-art research and emerging technologies related to the wheel/rail interface and its management. Part two offers an overview of industrial practice from several different regions of the world, thereby providing an invaluable international perspective with practitioners' experience of managing the wheel/rail interface in a variety of environments and circumstances.This comprehensive volume will enable practising railway engineers, in whatever discipline of railway engineering – infrastructure, vehicle design and safety, and so on – to enhance their understanding of wheel/rail issues, which have a major influence on the running of a reliable, efficient and safe railway. - One-stop reference on the important topic of wheel rail-interfaces - Presents the fundamentals of contact mechanics, wear, fatigue and lubrication - Examines state-of-the-art research and emerging technologies related to wheel-rail interface and its management

Download or read book Technical Literature Abstracts written by Society of Automotive Engineers and published by . This book was released on 1998 with total page 664 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Rail Vehicle Dynamics written by Klaus Knothe and published by Springer. This book was released on 2016-11-23 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book on the dynamics of rail vehicles is developed from the manuscripts for a class with the same name at TU Berlin. It is directed mainly to master students with pre-knowledge in mathematics and mechanics and engineers that want to learn more. The important phenomena of the running behaviour of rail vehicles are derived and explained. Also recent research results and experience from the operation of rail vehicles are included. One focus is the description of the complex wheel-rail contact phenomena that are essential to understand the concept of running stability and curving. A reader should in the end be able to understand the background of simulation tools that are used by the railway industry and universities today.

Download or read book Plasticity and Beyond written by Jörg Schröder and published by Springer Science & Business Media. This book was released on 2013-09-20 with total page 417 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book presents the latest findings in experimental plasticity, crystal plasticity, phase transitions, advanced mathematical modeling of finite plasticity and multi-scale modeling. The associated algorithmic treatment is mainly based on finite element formulations for standard (local approach) as well as for non-standard (non-local approach) continua and for pure macroscopic as well as for directly coupled two-scale boundary value problems. Applications in the area of material design/processing are covered, ranging from grain boundary effects in polycrystals and phase transitions to deep-drawing of multiphase steels by directly taking into account random microstructures.

Download or read book Impact written by Werner Goldsmith and published by Courier Corporation. This book was released on 2001-11-01 with total page 417 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carefully organized, skillfully written text examines stereomechanical impact; vibrational aspects of impact; contact phenomena produced by the impact of elastic bodies; dynamic processes involving plastic strains; results of impact experiments and dynamic properties of materials. Well-illustrated treatment presumes some knowledge of partial differential equations, operational calculus, and elasticity. 284 illustrations.

Download or read book Hemivariational Inequalities written by Panagiotis D. Panagiotopoulos and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 453 pages. Available in PDF, EPUB and Kindle. Book excerpt: The aim of the present book is the formulation, mathematical study and numerical treatment of static and dynamic problems in mechanics and engineering sciences involving nonconvex and nonsmooth energy functions, or nonmonotone and multivalued stress-strain laws. Such problems lead to a new type of variational forms, the hemivariational inequalities, which also lead to multivalued differential or integral equations. Innovative numerical methods are presented for the treament of realistic engineering problems. This book is the first to deal with variational theory of engineering problems involving nonmonotone multivalue realations, their mechanical foundation, their mathematical study (existence and certain approximation results) and the corresponding eigenvalue and optimal control problems. All the numerical applications give innovative answers to as yet unsolved or partially solved engineering problems, e.g. the adhesive contact in cracks, the delamination problem, the sawtooth stress-strain laws in composites, the shear connectors in composite beams, the semirigid connections in steel structures, the adhesive grasping in robotics, etc. The book closes with the consideration of hemivariational inequalities for fractal type geometries and with the neural network approach to the numerical treatment of hemivariational inequalities.