Improvements of conventional methods in railway track analysis and design

2010 ◽  
Vol 37 (5) ◽  
pp. 675-683 ◽  
Author(s):  
J. Sadeghi ◽  
P. Barati
Keyword(s):  
Support System ◽  
Design Method ◽  
Nonlinear Behavior ◽  
Field Investigation ◽  
Railway Track ◽  
Design Parameters ◽  
Element Analysis ◽  
Analysis And Design ◽  
The Impact ◽  
Track Analysis

The aim of this research is to improve the accuracy of conventional railway design methods by addressing the main track substructure parameters omitted in the current track design approach. Nonlinear and discrete properties of the track support system were studied and their influence on the calculation of railway design parameters was measured by conducting a field investigation and using finite element analysis. It was demonstrated that wheel loads and accumulative track loading are the key factors influencing nonlinear behavior of the track support system. Mathematical expressions were developed for the impact of the nonlinearity of the track support system based on the track analysis results, and correction factors were established for rail bending moments and rail deflections calculated by current methods. It was shown that the incorporation of these factors improves the accuracy and reliability of the conventional track design method.

A Simplified Design Model for Modular Steel Buildings Subject to Vapor Cloud Explosions (VCEs)

2020 ◽  
Vol 14 ◽  
Author(s):  
Osama Bedair
Keyword(s):  
Dynamic Response ◽  
Minimum Cost ◽  
Design Parameters ◽  
Front Wall ◽  
Steel Buildings ◽  
Element Analysis ◽  
Analysis And Design ◽  
Vapor Cloud ◽  
Building Components ◽  
Analytical Expressions

Background: Modular steel buildings (MSB) are extensively used in petrochemical plants and refineries. Limited guidelines are available in the industry for analysis and design of (MSB) subject to accidental vapor cloud explosions (VCEs). Objectives: The paper presents simplified engineering model for modular steel buildings (MSB) subject to accidental vapor cloud explosions (VCEs) that are extensively used in petrochemical plants and refineries. Method: A Single degree of freedom (SDOF) dynamic model is utilized to simulate the dynamic response of primary building components. Analytical expressions are then provided to compute the dynamic load factors (DLF) for critical building elements. Recommended foundation systems are also proposed to install the modular building with minimum cost. Results: Numerical results are presented to illustrate the dynamic response of (MSB) subject to blast loading. It is shown that (DLF)=1.6 is attained at (td/t)=0.4 for front wall (W1) with (td/T)=1.25. For side walls (DLF)=1.41 and is attained at (td/t)=0.6. Conclusions: The paper presented simplified tools for analysis and design of (MSB) subject accidental vapor cloud blast explosions (VCEs). The analytical expressions can be utilized by practitioners to compute the (MSB) response and identify the design parameters. They are simple to use compared to Finite Element Analysis.

IMPORTANCE OF NONLINEARITY OF TRACK SUPPORT SYSTEM IN MODELING OF RAILWAY TRACK DYNAMICS

2013 ◽  
Vol 13 (01) ◽  
pp. 1350008 ◽  
Author(s):  
J. SADEGHI ◽  
M. FESHARAKI
Keyword(s):  
Support System ◽  
Field Tests ◽  
Field Investigation ◽  
Dynamic Responses ◽  
Railway Track ◽  
Nonlinear Properties ◽  
Railway Tracks ◽  
Track Dynamics ◽  
Track System ◽  
Axle Loads

Attention is drawn to the fact that the recent increase in axle loads, speed and traffic volume in railway tracks, as well as concerns over passengers' riding comfort and safety have resulted in fresh challenges that are needed to be addressed. These challenges can only be successfully tackled with a more accurate modeling of the dynamic behavior of railway tracks. Although a significant amount of research involving mathematical modeling of railway track dynamics has been conducted in the last two decades, the nonlinearity of track support systems has not been given sufficient attention. This paper is concerned with the effect of nonlinearity of the support sub-layers on the dynamic responses of the railway track. To this end, a railway track model that considers the nonlinear properties of the track sub-layers is developed. Then, a field investigation into the dynamic responses of the railway track system under moving trains is conducted. The effect of the nonlinearity properties of the track support system on the track responses is investigated by comparing the results obtained by the numerical model, with or without consideration of track support nonlinearity, with those from the field tests. It is illustrated that consideration of the nonlinear properties of the track support system improves the accuracy of the calculated responses by a factor of three. It is also shown that the train axle loads and track accumulative loading have a significant effect on the nonlinearity of the track support system and, as a result, on the modeling of track responses.

Design of a Spacer Grid Using Axiomatic Design

2002 ◽  
Author(s):  
K. N. Song ◽  
B. S. Kang ◽  
K. H. Yoon ◽  
S. K. Choi ◽  
G. J. Park
Keyword(s):  
Cooling Water ◽  
Axiomatic Design ◽  
Axiomatic Approach ◽  
Design Parameters ◽  
Independence Axiom ◽  
Functional Requirements ◽  
Spacer Grid ◽  
Element Analysis ◽  
Detailed Design ◽  
Analysis And Design

Recently, much attention has been focused on the design of the fuel assemblies in the Pressurized Light Water Reactor (PLWR). The spacer grid is one of the main structural components in a fuel assembly. It supports fuel rods, guides cooling water, and maintains geometry from the external impact loads. In this research, a new shape of the spacer grid is designed by the axiomatic approach. The Independence Axiom is utilized for the design. For the conceptual design, functional requirements (FRs) are defined and corresponding design parameters (DPs) are found to satisfy FRs in sequence. Overall configuration and shapes are determined in this process. Detailed design is carried out based on the result of the axiomatic design. For the detailed design, the system performances are evaluated by using linear and nonlinear finite element analysis. The dimensions are determined by optimization. Some commercial codes are utilized for the analysis and design.

Analysis and Design of High-Speed Flywheel on Satellite Energy Storage/Attitude Control System

2009 ◽  
Vol 610-613 ◽  
pp. 408-413
Author(s):  
Jian Yu Zhang ◽  
Yue Fu ◽  
Li Bin Zhao ◽  
Jian Cheng Fang
Keyword(s):  
Attitude Control ◽  
High Speed ◽  
Outer Radius ◽  
Design Parameters ◽  
Analysis Model ◽  
Attitude Control System ◽  
Element Analysis ◽  
Analysis And Design ◽  
Rotor Structure ◽  
Flywheel Rotor

Flywheel rotor structure is one of essential assemblies of the flywheel system used in IPACS. It is significant to ensure the safety of metallic hub and the composite rim under high centrifugal loading induced by the rotation field and the surface pressure produced by the interface misfits. In this paper a 3-D stress analysis model of the flywheel rotor is presented with the finite element analysis software ANSYS and the failure criteria of the materials are discussed to assess the structural strength. Moreover, the key design parameters are investigated briefly to disclose their influences on the stress distribution of rotor structure. At last, an optimum mathematics model with the outer radius of metallic hub, the thickness of each composite ring and the interface misfits as the design variables is presented. Based on the optimum design platform, the series of flywheel rotor structures can be designed systematically.

scholarly journals An impact echo method to detect cavities between railway track slabs and soil foundation

2021 ◽  
Vol 68 (1) ◽  
Author(s):  
Pierre Anthyme Bahati ◽  
Viet Dinh Le ◽  
Yujin Lim
Keyword(s):  
Open Space ◽  
Concrete Slab ◽  
Test Methods ◽  
Railway Track ◽  
Element Analysis ◽  
Impact Echo ◽  
Time Frequency ◽  
Railway Tracks ◽  
Soil Foundation ◽  
The Impact

AbstractThe impact echo technique is one of the most useful non-destructive test methods for determining the thickness of concrete or detecting possible cracks or cavities in the internal parts of a concrete structure without damaging the surface. Many types of unstable conditions in railway tracks, including various modes of irregularities, may occur when cavities are generated directly under a concrete slab track or when a slight open space is made under a loose sleeper. In this study, we developed a nondestructive testing (NDT) system for detecting abnormalities in concrete tracks and performed 3D numerical simulations using the ABAQUS finite element analysis (FEA) program to investigate the impact echo response from a concrete track slab with different sizes of cavities. Sections of concrete slab were simulated as solid body masses under the railway tracks with gaps in the bodies themselves or with cavities existing between the track concrete layer (TCL) and the hydraulically stabilized base (HSB). We investigated the locations and depths of the cavities and gaps in the model concrete slab using the acoustic impact echo response based on the frequency response of the elastic waves generated in the slab. In addition, a Short-time Fourier Transform (STFT) and a wavelet technique were adopted for a time frequency analysis. Our study demonstrated that the impact echo technique developed in this study by FEA and NDT can measure and confirm the location and depth of cavities in concrete slabs.

Comparison of SCR Field Response With Analytical Predictions

2011 ◽  
Author(s):  
Yiannis Constantinides ◽  
Jen-hwa Chen ◽  
Lee Tran ◽  
Prahlad Enuganti ◽  
Mike Campbell
Keyword(s):  
Structural Response ◽  
Field Measurements ◽  
Design Parameters ◽  
Element Analysis ◽  
Steel Catenary Riser ◽  
Analysis And Design ◽  
Industry Standard ◽  
Fea Modeling ◽  
Actual Field ◽  
Deepwater Risers

Design of deepwater risers involves the use of multiple conservative design parameters to account for the uncertainty in the understanding of the behavior of complex structures. As the oil industry moves into deeper and harsher waters, the design tolerances are getting stretched. Chevron has been monitoring the structural response of a deepwater Gulf of Mexico steel catenary riser (SCR) to improve the understanding of riser behavior and to evaluate the existing analysis and design methodologies against actual field measurements. The following paper presents a selected set of results from benchmark of SCR response in storm conditions against analytical predictions, based on industry standard methodologies. The predictions are based on a finite element analysis (FEA) modeling of the riser structure with empirically formulated models for hydrodynamics and soil-structure interaction. Predicted riser response in terms of accelerations and stresses along the length are compared against field measurements showing good overall agreement.

A DSS User is a Happy Negotiator

2016 ◽  
pp. 590-611
Author(s):  
Patrick Hippmann
Keyword(s):  
Decision Support ◽  
Literature Review ◽  
Decision Support System ◽  
Decision Support Systems ◽  
Support System ◽  
Support Systems ◽  
Research Framework ◽  
Analysis And Design ◽  
The Impact ◽  
Research And Design

The present work states that the analysis and design of decision support systems should consider their impacts on the emotional behaviors of negotiators. This paper provides a brief literature review with respect to this issue, and an outline of a research framework, which explains how to assess and analyze the dynamics of emotional behaviors in text-based negotiations. Subsequently, it provides some results, which show that a decision support system does not mitigate but intensifies emotional behaviors, toward the end of successful as well as failed text-based online negotiations. It is concluded that the research and design of decision support systems should focus more on the impact such systems have on the emotional behaviors of the supported negotiators.

The Effect of Splicing Area Parameters on Mechanical Behavior of Beam-Column Connection with Cantilever Beam Splicing

2014 ◽  
Vol 919-921 ◽  
pp. 258-261
Author(s):  
Jian Rong Pan ◽  
Zheng Ting Yang ◽  
Lin Qiang Zheng ◽  
Rui Bin Gao
Keyword(s):  
Mechanical Behavior ◽  
Cantilever Beam ◽  
Ultimate Load ◽  
Design Method ◽  
Great Influence ◽  
Design Parameters ◽  
Rotational Stiffness ◽  
Element Analysis ◽  
Yield Load ◽  
The Finite Element Analysis

This paper deals with the effect of splicing area design parameters on the mechanical behavior of beam-column connection with cantilever beam splicing. A series of models are designed based on the change of parameters. The mechanical behavior of beam-column connection with cantilever beam splicing is systematically studied by using the finite element analysis. The analysis results show that the number and arrangement of web bolt will have a great influence on mechanical behavior of the splicing joint when the number of flange bolt is designed by the precise design method; the number and arrangement of web bolt will have a less influence when the number of flange bolt is designed by the equal strength design method; Splicing area design parameters have little effect on the ultimate load and the initial rotational stiffness of the splicing joint; the number and arrangement of bolt is sensitive parameter for yield load of the splicing joint and the rotational stiffness in the the splicing area.

A Multi-Body Dynamic Model for Analysis of Localized Track Responses in Vicinity of Rail Discontinuities

2016 ◽  
Vol 16 (09) ◽  
pp. 1550058 ◽  
Author(s):  
H. Askarinejad ◽  
M. Dhanasekar
Keyword(s):  
Dynamic Responses ◽  
Railway Track ◽  
Design Parameters ◽  
Valuable Insight ◽  
Modeling And Analysis ◽  
Impact Forces ◽  
Noise Vibration ◽  
Multi Body ◽  
The Impact ◽  
Body Dynamic

Rail discontinuities are one of the main sources of wheel impact causing high levels of noise, vibration and stresses in railway track. Even though various multi-body train–track interaction models have been developed in the past decade, accurate modeling and analysis of the track dynamic behavior in the vicinity of rail discontinuities is rare in the literature. In this paper, formulation of a new explicit multi-body dynamic (MBD) model incorporating detailed wagon, wheel–rail subsystems and track containing a rail discontinuity (rail joint) is reported. The predictions of the localized track responses are validated using the data from two gapped rail joints in the field test. The validated model accurately determines the impact forces and dynamic responses. The simulation results provide valuable insight on the behavior of track in vicinity of a rail discontinuity, the sensitivity of the design parameters to the impact forces and the track dynamic responses currently unavailable in the literature.

Numerical Analysis of Flush End-Plate Beam-to-Column Connection using Mathematical Model and Finite Element Analysis

2021 ◽  
Author(s):  
Mohammad Haroon Ehsan ◽  
Mutlu Seçer
Keyword(s):  
Mathematical Model ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Numerical Analysis ◽  
Numerical Models ◽  
Design Parameters ◽  
Engineering Practice ◽  
Element Analysis ◽  
Analysis And Design ◽  
End Plate

In the conventional analysis and design of steel structures, beam-to-column connections are generally assumed as entirely rigid or perfectly pinned. This assumption simplifies analysis and design steps and preferred extensively in structural engineering practice. However, experimental studies conducted in recent years have revealed that handling some of the beam-to-column connections as entirely rigid or perfectly pinned does not give realistic results. In fact, most of the connections used in current practice have some certain amount of stiffness which fall between the extreme cases of entirely rigid and perfectly pinned. In order to model the beam-to-column connections properly, several researchers have proposed various mathematical models based on experimental results. In these models, moment rotation relations of beam-to-column connections are defined according to the type of connection. In this study, moment-rotation behaviors of beam-to-column connections formed by flush end-plate are investigated using finite element analysis and a well-known practical mathematical model. Moreover, numerical analysis outcomes were compared with the test results of a reference study from the literature. This paper showed the importance of structural design parameters in determining moment-rotation relationship of flush end-plate type of beam-to-column connections and evaluated the efficiency of the practical numerical models.

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