Survivability of Railroad Tank Car Top Fittings in Rollover Scenario Derailments

2010 ◽  
Author(s):  
Robert S. Trent ◽  
Anand Prabhakaran ◽  
Francisco Gonza´lez ◽  
Vinaya Sharma ◽  
Srinivas Chitti
Keyword(s):  
Finite Element ◽  
Impact Energy ◽  
Longitudinal Velocity ◽  
Nonlinear Material ◽  
Protective Structure ◽  
Finite Element Analyses ◽  
Explicit Finite Element ◽  
Damage And Failure ◽  
Concrete Barrier ◽  
Validation Testing

Railroad tank car top fittings are susceptible to damage and failure in rollover derailments, which might result in release of hazardous material lading to the environment. In this paper, we propose and analyze five protective structure concepts designed to eliminate or reduce damage to these top fittings in a rollover derailment, using explicit finite element analyses incorporating nonlinear material and geometry models. Three different rollover scenarios are studied; a nominal rollover, a more severe rollover with greater impact energy, and a rollover combined with longitudinal velocity, with the tank car impacting a concrete barrier. The results from these analyses as well as plans for validation testing are presented in the paper.

Selective mass scaling for explicit finite element analyses

2005 ◽  
Vol 63 (10) ◽  
pp. 1436-1445 ◽  
Author(s):  
Lars Olovsson ◽  
Kjell Simonsson ◽  
Mattias Unosson
Keyword(s):  
Finite Element ◽  
Finite Element Analyses ◽  
Explicit Finite Element ◽  
Mass Scaling

Tank Car Puncture Analyses for Various Impactors and Impact Conditions

2013 ◽  
Author(s):  
Steven W. Kirkpatrick ◽  
Francisco Gonzalez ◽  
Karl Alexy
Keyword(s):  
Finite Element ◽  
Research Program ◽  
Impact Testing ◽  
Impact Behavior ◽  
Finite Element Analyses ◽  
Damage And Failure ◽  
Wide Range ◽  
Significant Research ◽  
Detailed Simulation ◽  
The Impact

There has been significant research in recent years to analyze and improve the impact behavior and puncture resistance of railroad tank cars. Much of this research has been performed using detailed nonlinear finite element analyses supported by full scale impact testing. This use of detailed simulation methodologies has significantly improved our understanding of the tank impact behaviors and puncture prediction. However, the evaluations in these past studies were primarily performed for a few idealized impact scenarios. This paper describes a research program to evaluate railroad tank car puncture behaviors under more general impact conditions. The approach used in this research program was to apply a tank impact and puncture prediction capability using detailed finite element analyses (FEA). The analysis methodologies apply advanced damage and failure models that were validated by series of material tests under various loading conditions. In this study, the analyses were applied to investigate the tank puncture behaviors for a wide range of impact conditions.

Probabilistic Models to Approximate Highly Repetitive Linear and Nonlinear Finite Element Analyses of Nuclear Components

2009 ◽  
Author(s):  
Dan Vlaicu ◽  
Mike Stojakovic
Keyword(s):  
Finite Element ◽  
Material Properties ◽  
Probabilistic Models ◽  
Nonlinear Material ◽  
Superposition Method ◽  
Loading Conditions ◽  
Finite Element Analyses ◽  
Axisymmetric Nozzle ◽  
Nonlinear Superposition ◽  
Pipe Bend

In the development and technical support of nuclear plants, Engineers have to deal with highly repetitive finite element analyses that involve modeling of local variations of the initial design, local flaws due to corrosion-erosion effects, material properties degradation, and modifications of the loading conditions. This paper presents the development of generic models that emulate the behavior of a complex finite element model in a simplified form, with the statistical representation based on a sampling of base-model data for a variety of test cases. An improved Latin Hypercube algorithm is employed to generate the sampling points based on the number and the range of the variables that are considered in the design space. Four filling methods of the approximation models are discussed in this study: response surface, nonlinear, neural networks, and piecewise polynomial model. Furthermore, a bootstrapping procedure is employed to improve the confidence intervals of the original coefficients, and the single-factor or double-factor analysis of variance is applied to determine whether a significant influence exists between the investigated factors. Two numerical examples highlight the accuracy and efficiency of the methods. The first example is the linear elastic analysis of a pipe bend under pressure loading. The objective of the probabilistic assessment is to determine the relation between the loading conditions as well as the geometrical aspects of this elbow (pipe wall thickness, outside diameter, elbow radius, and maximum ovality tolerance) and the maximum stress in the elbow. The second example is an axisymmetric nozzle under primary and secondary cycling loads. Variations of the geometrical dimensions, nonlinear material properties, and cycling loading are taken as the input parameters, whereas the response variable is defined in terms of Melan’s theorem translated into the Nonlinear Superposition Method.

Ice Floe-induced Ship Resistances using Explicit Finite Element Analyses with a User-subroutine

2020 ◽  
Vol 57 (2) ◽  
pp. 88-95
Author(s):  
Donghwa Han ◽  
Kwang-Jun Paik ◽  
Seong-Yeop Jeong ◽  
Joonmo Choung
Keyword(s):  
Finite Element ◽  
Finite Element Analyses ◽  
Explicit Finite Element ◽  
User Subroutine

Alternative Selections of Delayed Coke Drum Materials Based on ASME Material Property Data

2012 ◽  
Author(s):  
Milan Nikic ◽  
Zihui Xia
Keyword(s):  
Finite Element ◽  
Material Property ◽  
Base Material ◽  
Operating Conditions ◽  
Finite Element Analyses ◽  
Damage And Failure ◽  
Property Data ◽  
Operation Cycle ◽  
Heating Up ◽  
Material Property Data

Severe cyclic thermo-mechanical operating conditions during delayed coking can cause damages in the form of bulging and cracking in coke drums. As a result, the industry has to perform costly repairs and maintenance shutdowns. Therefore, it is important to understand the damage and failure mechanisms of the coke drums and to achieve more reliable coke drum design solutions. This paper explores alternative selections of clad and base material combinations for coke drum applications based on material property data provided in ASME Boiler & Pressure Vessel Code, Section II - Materials. Finite element analyses are carried out by simulating two critical loading scenarios in the coke drum operation cycle, i.e. the heating up and quenching stages. The analysis results show that the major achievement in lowering the stress level in the clad layer is due to matching of the coefficients of thermal expansion between clad and base materials. In addition, the finite element analyses indicate that the differences in Young’s modulus values play an important role in the variation of maximum stress in the coke drum shell during the quenching stage. Among eleven pairs of the clad and base material combinations studied, the combination of SA302-C as the base and nickel alloy N06625 as the cladding material is recommended.

Analysis for Material Behavior of Sabot/Rods During Launch by Finite Element Method

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1884-1890 ◽  
Author(s):  
Jin Bong Kim ◽  
Man Geun Kim
Keyword(s):  
Finite Element ◽  
Parametric Model ◽  
Material Behavior ◽  
Lateral Acceleration ◽  
Nonlinear Material ◽  
Stress And Strain ◽  
Finite Element Analyses ◽  
Engineering Analysis ◽  
Initial State ◽  
Initial Shape

This study has been investigated to predict the deformation and states of stress and strain by axial and lateral acceleration during launch. Because a gun tube is not perfectly straight at its initial state while under gravity loading, the projectile deforms due to the change of contacts points with the flexible gun tube. Numerical simulations were used for gravity loading and the other type is initial shape and gravity loading. The ANSYS engineering analysis code was used to generate a parametric model of the projectile and conduct finite element analyses. Four types of nonlinear material and contact elements were incorporated into the model to account for the plastic deformation and contact between the penetrator, sabot, and tube.

Prediction of Tread Pattern Wear by an Explicit Finite Element Model3

2007 ◽  
Vol 35 (4) ◽  
pp. 276-299 ◽  
Author(s):  
J. C. Cho ◽  
B. C. Jung
Keyword(s):  
Finite Element ◽  
Wear Rate ◽  
Tangential Stress ◽  
Rate Equation ◽  
Constitutive Equations ◽  
Slip Velocity ◽  
Test Results ◽  
Explicit Finite Element ◽  
Driving Condition ◽  
Driving Conditions

Abstract Tread pattern wear is predicted by using an explicit finite element model (FEM) and compared with the indoor drum test results under a set of actual driving conditions. One pattern is used to determine the wear rate equation, which is composed of slip velocity and tangential stress under a single driving condition. Two other patterns with the same size (225/45ZR17) and profile are used to be simulated and compared with the indoor wear test results under the actual driving conditions. As a study on the rubber wear rate equation, trial wear rates are assumed by several constitutive equations and each trial wear rate is integrated along time to yield the total accumulated wear under a selected single cornering condition. The trial constitutive equations are defined by independently varying each exponent of slip velocity and tangential stress. The integrated results are compared with the indoor test results, and the best matching constitutive equation for wear is selected for the following wear simulation of two other patterns under actual driving conditions. Tens of thousands of driving conditions of a tire are categorized into a small number of simplified conditions by a suggested simplification procedure which considers the driving condition frequency and weighting function. Both of these simplified conditions and the original actual conditions are tested on the indoor drum test machines. The two results can be regarded to be in good agreement if the deviation that exists in the data is mainly due to the difference in the test velocity. Therefore, the simplification procedure is justified. By applying the selected wear rate equation and the simplified driving conditions to the explicit FEM simulation, the simulated wear results for the two patterns show good match with the actual indoor wear results.

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