Vision for Mechanistic-Empirical Railway Track System and Component Analysis and Design

2021 ◽  
pp. 036119812110098
Author(s):  
J. Riley Edwards ◽  
Ricardo J. Quirós-Orozco ◽  
Josué César Bastos ◽  
Marcus S. Dersch ◽  
Erol Tutumluer
Keyword(s):  
Structural Reliability ◽  
Failure Modes ◽  
Mechanical Load ◽  
Component Analysis ◽  
Railway Track ◽  
Future Research ◽  
Analysis And Design ◽  
Future Design ◽  
Load Response ◽  
Track System

Many analytical methods and other processes have been developed for the evaluation of railway track and its components, but these have largely been used for analysis. Design is often driven by development projects that do not engage research, resulting in designs that may not be optimized in the context of the broader track structure. This paper proposes a mechanistic-empirical (M-E) analysis and design framework that encourages an understanding of mechanical load-response behavior and comparison of loading demands, and the capacity of the track infrastructure component under study. The approach builds on similar advancements in the field of highway pavement research, including the development and use of the Mechanistic-Empirical Pavement Design Guide (MEPDG). Rail applications present unique economies to a focused M-E design approach, given that loads are concentrated in localized regions and beneath the rails. This paper first reviews prior design and analysis approaches, then presents the essential features of an M-E railway track system and component analysis and design, and, in the end, notes gaps that will require future research before proper implementation of M-E design within rail engineering. The authors also discuss the role of probabilistic design and structural reliability analysis in future design practices. Finally, governing mechanistic failure modes for the track system as well as components and associated life cycle data to achieve full implementation of such an M-E design process are identified and a path forward for implementation is proposed.

Investigation of free vibrations of voided concrete sleepers in railway track system

2007 ◽  
Vol 221 (4) ◽  
pp. 495-507 ◽  
Author(s):  
S Kaewunruen ◽  
A M Remennikov
Keyword(s):  
Free Vibration ◽  
Free Vibrations ◽  
Vertical Vibration ◽  
Railway Track ◽  
Analysis And Design ◽  
Response Characteristics ◽  
Full Contact ◽  
Track System ◽  
Full Interaction

Concrete railway sleepers in ballasted track are laid on ballast and subgrade supporting systems. Full contact between sleepers and ballast is typically assumed for analysis and design purposes. Often, voids and pockets in the sleeper/ballast contact interface form between sleepers and the ballast underneath that could cause problems to both the sleepers and the track system as a whole. The current paper investigates the effects of ballast voids and pockets on free vibration response characteristics of in situ railway concrete sleepers. Finite-element modelling was employed to develop a dynamic model of the railway track incorporating concrete sleepers. This model includes the dynamic interaction of sleepers and ballast as part of the free vibration analyses of the in situ railway concrete sleepers. Several patterns of voids and pockets underneath railway sleepers were studied. The emphasis was placed on partial and full interaction between sleepers and ballast. The information on the vertical vibration modes provides an important insight into the dynamic response of concrete railway sleepers in different void-and-pocket configurations.

Experimental evaluation of accuracy of current practices in analysis and design of railway track sleepers

2008 ◽  
Vol 35 (9) ◽  
pp. 881-893 ◽  
Author(s):  
J. M. Sadeghi
Keyword(s):  
Current Method ◽  
Distribution Patterns ◽  
Field Investigation ◽  
Railway Track ◽  
Wheel Load ◽  
Analysis And Design ◽  
Load Factors ◽  
Track System ◽  
Static And Dynamic Loads ◽  
Made In

This research investigates the accuracy of the assumptions made in the current method of analysis and design of railway track sleepers. This study consists of a comprehensive field investigation into the response of sleepers in a railway track system to static and dynamic loads. In the experiments, several load cells (load gauges) are installed under a rail seat and beneath a B70 concrete sleeper for the purpose of monitoring the response of the sleeper to vertical loads. The dynamic coefficients factor, the ratio of the rail seat load to the wheel load and the pressures between the sleeper and the ballast are measured. The results are used to evaluate the current approaches for the analysis and design of concrete sleepers, in particular those proposed by the Americans (AREMA) and Europeans (UIC). New models are proposed for the calculation of dynamic load factors, correlations between wheel loads and rail seat loads, and load distribution patterns beneath sleepers.

Evolution of seismic design codes of highway bridges in Chile

2021 ◽  
pp. 875529302098801
Author(s):  
José Wilches ◽  
Hernán Santa Maria ◽  
Roberto Leon ◽  
Rafael Riddell ◽  
Matías Hube ◽  
...  
Keyword(s):  
Seismic Design ◽  
Failure Modes ◽  
Highway Bridges ◽  
Design Codes ◽  
Seismic Codes ◽  
Analysis And Design ◽  
Residual Displacements ◽  
Shear Keys ◽  
Maule Earthquake ◽  
2010 Maule Earthquake

Chile, as a country with a long history of strong seismicity, has a record of both a constant upgrading of its seismic design codes and structural systems, particularly for bridges, as a result of major earthquakes. Recent earthquakes in Chile have produced extensive damage to highway bridges, such as deck collapses, large transverse residual displacements, yielding and failure of shear keys, and unseating of the main girders, demonstrating that bridges are highly vulnerable structures. Much of this damage can be attributed to construction problems and poor detailing guidelines in design codes. After the 2010 Maule earthquake, new structural design criteria were incorporated for the seismic design of bridges in Chile. The most significant change was that a site coefficient was included for the estimation of the seismic design forces in the shear keys, seismic bars, and diaphragms. This article first traces the historical development of earthquakes and construction systems in Chile to provide a context for the evolution of Chilean seismic codes. It then describes the seismic performance of highway bridges during the 2010 Maule earthquake, including the description of the main failure modes observed in bridges. Finally, this article provides a comparison of the Chilean bridge seismic code against the Japanese and United States codes, considering that these codes have a great influence on the seismic codes for Chilean bridges. The article demonstrates that bridge design and construction practices in Chile have evolved substantially in their requirements for the analysis and design of structural elements, such as in the definition of the seismic hazard to be considered, tending toward more conservative approaches in an effort to improve structural performance and reliability for Chilean bridges.

Influence of Human Error on Structural Reliability

2017 ◽  
Author(s):  
Eric Brehm ◽  
Robert Hertle ◽  
Markus Wetzel
Keyword(s):  
Human Error ◽  
Structural Reliability ◽  
Failure Modes ◽  
Structural Model ◽  
Limit State ◽  
Design Procedure ◽  
Material Strength ◽  
Limit States ◽  
The Impact

In common structural design, random variables, such as material strength or loads, are represented by fixed numbers defined in design codes. This is also referred to as deterministic design. Addressing the random character of these variables directly, the probabilistic design procedure allows the determination of the probability of exceeding a defined limit state. This probability is referred to as failure probability. From there, the structural reliability, representing the survival probability, can be determined. Structural reliability thus is a property of a structure or structural member, depending on the relevant limit states, failure modes and basic variables. This is the basis for the determination of partial safety factors which are, for sake of a simpler design, applied within deterministic design procedures. In addition to the basic variables in terms of material and loads, further basic variables representing the structural model have to be considered. These depend strongly on the experience of the design engineer and the level of detailing of the model. However, in the clear majority of cases [1] failure does not occur due to unexpectedly high or low values of loads or material strength. The most common reasons for failure are human errors in design and execution. This paper will provide practical examples of original designs affected by human error and will assess the impact on structural reliability.

Evaluation of the Effect of Yield to Tensile (Y/T) Ratio on the Structural Integrity of Offshore Pipeline by Limit State Design Approach

2006 ◽  
Author(s):  
Gianluca Mannucci ◽  
Giuliano Malatesta ◽  
Giuseppe Demofonti ◽  
Marco Tivelli ◽  
Hector Quintanilla ◽  
...  
Keyword(s):  
Structural Reliability ◽  
Failure Modes ◽  
Structural Integrity ◽  
Limit State ◽  
Minor Effect ◽  
Offshore Pipelines ◽  
Limit State Design ◽  
A Minor ◽  
Probabilistic Failure Analysis ◽  
Failure Probabilities

Nowadays specifications require strict Yield to Tensile ratio limitation, nevertheless a fully accepted engineering assessment of its influence on pipeline integrity is still lacking. Probabilistic analysis based on structural reliability approach (Limit State Design, LSD) aimed at quantifying the yield to tensile strength ratio (Y/T) influence on failure probabilities of offshore pipelines was made. In particular, Tenaris seamless pipe data were used as input for the probabilistic failure analysis. The LSD approach has been applied to two actual deepwater design cases that have been on purpose selected, and the most relevant failure modes have been considered. Main result of the work is that the quantitative effect of the Y/T ratio on failure probabilities of a deepwater pipeline resulted not so big as expected; it has a minor effect, especially when Y only governs failure modes.

scholarly journals Mechanism reliability and sensitivity analysis of landing gear under multiple failure modes

2021 ◽  
Vol 39 (1) ◽  
pp. 46-54
Author(s):  
Changcong Zhou ◽  
Mengyao Ji ◽  
Yishang Zhang ◽  
Fuchao Liu ◽  
Haodong Zhao
Keyword(s):  
Failure Probability ◽  
Failure Modes ◽  
Kriging Model ◽  
Landing Gear ◽  
Multiple Failure Modes ◽  
Analysis And Design ◽  
Extension System ◽  
Extension Mechanism ◽  
Assembly Error ◽  
Adaptive Kriging

For a certain type of aircraft landing gear retraction-extension mechanism, a multi-body dynamic simulation model is established, and the time-dependent curves of force and angle are obtained. Considering the random uncertainty of friction coefficient, assembly error, and the change of hinge wear under different retraction times, the reliability model is built including three failure modes of landing gear, i.e. blocking failure, positioning failure and accuracy failure. Based on the adaptive Kriging model, the reliability and sensitivity of retraction-extension system under the condition of single failure mode and multiple failure modes in series are analyzed, and the rule of reliability and sensitivity changing with the number of operations is given. The results show that the system failure probability of landing gear mechanism tends to decrease first and then increase when considering the given information of random factors, and the influences of random factors on the failure probability vary with the number of operations. This work provides a viable tool for the reliability analysis and design of landing gear mechanisms.

scholarly journals Developing and Implementing a Conceptual Composite Materials Design Database

1993 ◽  
Author(s):  
William J. Rasdorf ◽  
Lisa K. Spainhour
Keyword(s):  
Composite Materials ◽  
Computer Technology ◽  
Data Model ◽  
Data Representation ◽  
Future Research ◽  
Clear Understanding ◽  
Analysis And Design ◽  
Problems And Solutions ◽  
Software Interfaces ◽  
Design Software

Abstract Researchers and materials engineers require a greater understanding of the problems and solutions that emerge when integrating composite materials data with computer technology so that utilitarian composite materials databases can be developed to effectively and efficiently support analysis and design software. Composite materials constitute a representational challenge due to their composition and use. However, this paper suggests that a conceptual composite material data model and application software interfaces must be developed to support the dissemination and use of composite materials data. This paper primarily serves to analyze several of the problems facing developers of composite materials databases, evolving from the complexity of the materials themselves and from the current lack of testing and data representation standards. Without a clear understanding of the scope and nature of these problems, there is no possibility of designing concise yet comprehensive composites data models, yet we feel that such an understanding is presently lacking. In addition, an effort is made to present possible solutions to these difficulties being suggested and/or implemented both by the authors and by other researchers in the field. Such an effort provides a firm foundation upon which future research may be based.

scholarly journals Analysis and Design of Sales Information System on Web-Based E-Commerce in Yoga Farm Catfish Breeding Business Using UML

2020 ◽  
Vol 4 (3) ◽  
pp. 683
Author(s):  
Muhamad Ridho Dwi Cahyo ◽  
Candiwan Candiwan
Keyword(s):  
Information System ◽  
Business Processes ◽  
Product Information ◽  
Small And Medium Enterprises ◽  
Unified Modeling Language ◽  
Future Research ◽  
Web Based ◽  
Unified Modeling ◽  
Analysis And Design ◽  
Medium Enterprises

Yoga Farm is a Micro, Small, and Medium Enterprises (MSME) that focuses on catfish breeding that is still doing business processes manually. With this process, information received by related parties is very difficult to obtain quickly. Therefore, the product is still not widely known, and customers are still few because the system used in sales and promotions still uses a manual system. The research method used is qualitative. This study aims to create a sales information system recommended at Yoga Farm and design using Unified modeling language (UML) for the recommended business processes. Customers will get product information in real-time, products can be widely recognized, and the number of Yoga Farm customers can increase. Based on the results of this study, adoption of a web-based sales information system can certainly make it easier to get the latest information quickly, can expand the market and can also facilitate customers in the transaction. For future research, this research can be used as a reference for conducting similar studies at other MSMEs to increase sales

scholarly journals ROLE OF TEAMWORK FOR ACTIVE LEARNING IN ELECTRICAL ENGINEERING EDUCATION

2020 ◽  
pp. 1-14
Author(s):  
Hale BÜTÜN BAYRAM ◽  
Erhan BÜTÜN
Keyword(s):  
Engineering Education ◽  
Future Research ◽  
Future Design ◽  
Class Time ◽  
Extra Information ◽  
Electrical Engineering Education ◽  
Laboratory Manuals ◽  
Higher Order Learning ◽  
Clear Idea

In engineering education, a project can rarely be completed without the involved students having to read extensively and search for extra information not available in their textbooks, lecture notes, or laboratory manuals. Students have to find extra information for their research-projects and combine them with their knowledge from the other courses. This important objective opens students’ eyes to the realization that the degree by which they have digested the fundamental ideas of their core lessons will dictate their ability to access more knowledge because they appear to face paradoxes when confronting new situations. The merits of teamwork have been sacrificed for the sake of giving the student a very clear idea of the meaning of scientific research and significance of published material. It is expected to aid the student in a future research-oriented career. Teamwork will increase the amount of time spent on out-of-class learning as defined by the student, can be more effective than in-class time, particularly if the focus is learning on higher order learning. The authors believe that the student will be sufficiently exposed to teamwork values during their future design projects.

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