scholarly journals Fuel Tank Crashworthiness: Loading Scenarios

2011 ◽  
Author(s):  
Karina Jacobsen
Keyword(s):  
Oblique Impact ◽  
Fuel Tank ◽  
Passenger Rail ◽  
Equipment Safety ◽  
Impact Location ◽  
Fuel Tanks ◽  
Serious Injury ◽  
Conducting Research ◽  
Railroad System ◽  
The U.S

The Federal Railroad Administration’s Office of Research and Development is conducting research into fuel tank crashworthiness. The breaching of fuel tanks during passenger rail collisions and derailments increases the potential of serious injury and fatality due to fire. This paper identifies and describes common collision loading scenarios for locomotive fuel tanks on the U.S. general railroad system. Developing scenarios that characterize this situation is the first step in crashworthiness research methodology for improving rail equipment safety. A survey of accidents within the U.S. between 1995 and present was used to identify fuel tank impact scenarios as follows: impact with adjacent railcar component; oblique impact with another railcar; rollover leading to impact with another railcar; derailment or rollover leading to grounding; and impact with rail. These collision scenarios are further categorized by the types of collision modes experienced by the fuel tank, i.e. impact type and impact location. These loading conditions establish targets for evaluating current levels of fuel tank integrity and potentially developing improved strategies for enhancing fuel tank integrity.

Updated Fuel Tank Puncture Survey: 1995-2020

2021 ◽  
Author(s):  
Karina Jacobsen
Keyword(s):  
Fuel Tank ◽  
Technical Data ◽  
Passenger Rail ◽  
Blunt Impact ◽  
Field Investigations ◽  
Fuel Tanks ◽  
Serious Injury ◽  
Conducting Research ◽  
Railroad System ◽  
General Operation

Abstract The Federal Railroad Administration’s Office of Research, Development and Technology has been conducting research into passenger fuel tank crashworthiness. The occurrence of a fuel tank puncture during passenger rail collisions and derailments increases the potential of serious injury and fatality for crew and passengers due to the possibility of fire. The purpose of the FRA research is to help support regulatory and standard development with technical data. In the last decade, the research has focused on understanding how fuel tanks are punctured during an impact and how various tank designs respond to common types of loading in collisions, derailments and general operation. Throughout the research, surveys have been conducted to determine the most likely scenarios that are causing fuel tank punctures. A previous FRA survey found that fuel tank punctures occur under two types of loading conditions: a blunt impact or a raking impact. A limited number of accident/incidents were evaluated in this survey. These incidents showed that fuel tanks are punctured on any side that is not protected or shielded. The purpose of this paper is to report on a recently conducted fuel tank puncture survey updated to include the last decade. This paper identifies and describes accidents and incidents that led to breached fuel tanks in freight and passenger trains traveling on the general railroad system in the U.S. between 2008 and 2020. The results include data from the FRA’s Railroad Accident/Incident Reporting System (RAIRS), queried from 1995 to 2020. This data include the number of recorded accidents/incidents and other trends like fuel spillage, operating authority and cause of accident/incident. RAIRS data showed accidents/incidents with fuel tank puncture ranging from 10 to 55 accidents/incidents per year. Additionally, more detailed results are shared from field investigations recently conducted by the FRA or Volpe Center. These more detailed investigations provide additional insight into the types of loading that may lead to a fuel tank puncture. This survey supplements the RAIRS data with more detailed information from field investigations. The paper finally discusses the conditions that lead to fire and the associated hazards.

scholarly journals Side Structure Integrity Research for Passenger Rail Equipment

2018 ◽  
Author(s):  
Shaun Eshraghi ◽  
Michael Carolan ◽  
A. Benjamin Perlman
Keyword(s):  
Transportation Systems ◽  
Side Impact ◽  
Transportation Safety ◽  
Safety Standards ◽  
Passenger Rail ◽  
Equipment Safety ◽  
The Status ◽  
Grade Crossing ◽  
Conducting Research ◽  
Performance Validation

The U.S. Department of Transportation (DOT) Federal Railroad Administration (FRA) began promulgating regulations for the structural crashworthiness of passenger rail equipment at 49 Code of Federal Regulations (CFR) Part 238 on May 12, 1999. These Passenger Equipment Safety Standards (PESS) [1] include requirements affecting the designs of sidewall structures on passenger rail equipment. The FRA’s Office of Research, Development and Technology and the DOT’s Volpe National Transportation Systems Center are conducting research to evaluate the side impact strength of Tier I passenger rail equipment designs that have been constructed according to the current side structure regulations in §238.215 and §238.217. Following a fatal 2011 accident in which a highway semitrailer truck impacted the side of a passenger train that was transiting a grade crossing in Miriam, NV, the National Transportation Safety Board (NTSB) recommended that the FRA “develop side impact crashworthiness standards (including performance validation) for passenger railcars that provide a measurable improvement compared to the current regulation for minimizing encroachment to and loss of railcar occupant survival space” [2]. This paper describes the status of the current FRA research related to side structure integrity and describes the planned next stage of the research program which will include analyzing the performance of generalized passenger railcar structures in side impact collision scenarios. A discussion of the technical challenges associated with analyzing side impacts on passenger rail equipment is also presented.

scholarly journals Conventional Fuel Tank Blunt Impact Tests: Test and Analysis Results

2014 ◽  
Author(s):  
Karina Jacobsen ◽  
Michael Carolan ◽  
Benjamin Perlman
Keyword(s):  
Finite Element ◽  
Dynamic Loading ◽  
Fuel Tank ◽  
Test Tank ◽  
Impact Tests ◽  
Impact Location ◽  
Blunt Impact ◽  
Fuel Tanks ◽  
Post Test ◽  
The Impact

The Federal Railroad Administration’s Office of Research and Development is conducting research into fuel tank crashworthiness. A series of impact tests are planned to measure fuel tank deformation under two types of dynamic loading conditions — blunt and raking impacts. This paper describes the results of the first set of blunt impact tests for two retired EMD F-40 locomotive fuel tanks, Tank 232 and Tank 202. On October 8, 2013 and October 9, 2013, the FRA performed impact tests on two conventional passenger locomotive fuel tanks at the Transportation Technology Center (TTC) in Pueblo, Colorado. Each fuel tank was emptied of fluid and mounted on a crash wall with the bottom surface exposed. A rail cart modified with a “rigid” indenter was released to impact the center of the bottom of each fuel tank at about 6 mph. A center-impact on Tank 232 was chosen to impact between two baffles. A center-impact on Tank 202 was chosen to impact on a baffle. In the first test, Tank 232 was impacted by the indenter at 4.5 mph. The maximum residual indentation on the bottom of the tank measured approximately 5 inches. The tank deformed across the middle longitudinal span of the tank forming a diamond-shaped indention. In the second test, Tank 202 was impacted by the indenter at 6.2 mph. The maximum residual indentation on the bottom of the tank measured approximately 1.5 inches. The bottom of the tank deformed with an “X” shape spanning out from the location of square indenter at the center of the tank. Post-test autopsies revealed the deformation of the interior structures, i.e. baffles and attachments. There was no damage to the baffles in Tank 232. Deformation to the interior structure of Tank 202 was limited to the baffle directly beneath the impact location, which folded in the area near the impact location. Material coupons were cut and tensile testing performed to determine the properties of the materials used in each tank. Prior to the test, computer models were developed from measurements taken on the test articles. Material properties were estimated based on Brinell hardness measurements. Computer analyses were conducted to determine the conditions for the test, i.e. instrumentation, location of impact, target impact speeds and to predict the deformation behavior of the tank. Post-test, the resulting stress-strain relationships for the bottom sheets and baffles of both tanks were used to update the finite element models of the two tanks. The models were also updated to reflect the actual geometry of the tanks as confirmed by measurements of the tank interiors. The results of the finite element (FE) models run at the test conditions with the updated tank details are compared with the results from the test itself. Specifically, the deformation progression and the residual dent depth are compared between the tests and the models. In accidents, fuel tanks are subjected to dynamic loading, often including a blunt or raking impact from various components of the rolling stock or trackbed. Current design practice requires that fuel tanks have minimum properties adequate to sustain a prescribed set of static load conditions. Current research is intended to increase understanding of the impact response of fuel tanks under dynamic loading.

Fuel Leaking Analysis of Fuel Tank by Projectiles Impact with Mechanical Properties of Projectiles

2013 ◽  
Vol 644 ◽  
pp. 203-206
Author(s):  
Hai Liang Cai ◽  
Bi Feng Song ◽  
Yang Pei ◽  
Shuai Shi
Keyword(s):  
High Speed ◽  
Drop Size ◽  
Fuel Tank ◽  
Size Distributions ◽  
Sauter Mean Diameter ◽  
Fuel Droplets ◽  
High Speed Impact ◽  
Fuel Tanks ◽  
Rigid Projectile ◽  
Drop Size Distributions

For making sure the dry bay ignition and fire, it’s necessary to calculate the number and the sizes of the droplets and determine the mass flow rate of the fuel induced by high-speed impact and penetration of a rigid projectile into fuel tank. An analytical model is founded and the method for calculating the initial leaking velocity of the fuel is determined. It gives the equation for calculating the drop size distributions of fuel and the Sauter mean diameter (SMD) of droplets, through the Maximum Entropy Theory and the conservation for mass. Using the Harmon’s equation for SMD,the fuel droplets SMD can be calculated. Results shows that the initial leaking velocity of the fuel is about linearly increasing with the velocity of the projectile, the SMD of fuel droplets increases with the hole size of the fuel tank which induced by the penetration of the projectile and linearly decreases with the velocity of the projectile. The results can be used for the ignition and fire analysis of the dry bay adjacent to fuel tanks.

Study Regarding the Influence of the Fuel Tank Constructive Characteristics on Slosh-Noise Effect

2016 ◽  
Vol 834 ◽  
pp. 22-27 ◽  
Author(s):  
Oana Maria Manta Balas ◽  
Radu Balas ◽  
Cristian Vasile Doicin
Keyword(s):  
The Body ◽  
Fuel Tank ◽  
Noise Effect ◽  
Great Achievement ◽  
Fuel Tanks ◽  
Entire Vehicle ◽  
Body In White ◽  
Innovative Potential ◽  
The Impact ◽  
The Waves

The aim of this article is to highlight the impact of the fuel movements inside the plastic fuel tank (waves) for the client perception of noise. Today there isn’t a clear methodology regarding the reproducing the fuel waves, but there are different approaches to be taken into account and also there is an innovative potential. Due to the fast technological progress the body in white and not only, the entire vehicle became lighter and lighted. A consequence of this great achievement is that the client can hear easier the sound produced by different components of the car. The plastic fuel tank can be considered such a component. The authors have done a deep analysis of present automotive fuel tanks and propose solutions for breaking the waves produced inside fuel tanks, so as to reduce the slosh noise effect. The studies will be continued during the doctoral approach of the first author.

Analysis of Tiplock Phenomenon in Extension Ladders

2004 ◽  
Author(s):  
John S. Morse ◽  
C. Russ Rasnic
Keyword(s):  
Geometric Analysis ◽  
Mathematical Expression ◽  
Physical Measurement ◽  
Lock Mode ◽  
Serious Injury ◽  
Tip Radius ◽  
The U.S

Extension ladder accidents injure thousands of people each year in the U.S. One cause of these accidents is false lock of the flylocks. Flylocks are the devices that support the upper or fly section of an extended ladder. False locked flylocks are not fully locked, but nevertheless support a load. False lock is not stable and may release under disturbance of the ladder, e.g. from climbing. False lock modes include tiplock, flipperlock, and camlock. If a false lock releases the ladder will telescope, and may cause serious injury. One false lock mode is tiplock, where the tip of the flylock is resting on the rung of the ladder in a metastable position. The tiplock may be held in place by mechanical locking, or by friction between the tip and the rung. Tiplock may occur when the ladder is being extended and the fly section is not raised enough to fully engage the flylocks. Ladder labels usually instruct “Securely engage ladder locks before climbing,” but typically do not instuct a user how to do this. Ladder users employ various methods to securely engage flylocks. These methods do not always prevent false lock. No gravity or spring actuated flylock design is known which will completely eliminate tiplock, but various designs have different ranges of fly section travel over which tiplock can occur (tiplock “window”). A mathematical expression defines the conditions under which friction tiplock can occur. Two methods of evaluating the tiplock window are discussed: geometric analysis and physical measurement. Tiplock propensity during random ladder extension is calculated. A geometric analysis is made of two flylocks with different tip radii. The flylock with the smaller tip radius is observed to have a smaller tiplock window.

Numerical research on sloshing of free oil liquid surface based on different baffle shapes in rectangular fuel tank

2019 ◽  
Vol 234 (2-3) ◽  
pp. 363-377 ◽  
Author(s):  
Enhui Zhang
Keyword(s):  
Liquid Surface ◽  
Physical Phenomenon ◽  
Central Line ◽  
Fuel Tank ◽  
Central Point ◽  
Liquid Sloshing ◽  
Straight Line ◽  
Fuel Tanks ◽  
Different Shapes ◽  
Sloshing Pressure

Oil liquid sloshing is a normal physical phenomenon in fuel tank under variable conditions of vehicles. Installing baffles in fuel tank is an effective method to suppress oil liquid sloshing. The influence of different baffle shapes on the pressure of oil liquid sloshing and time-area value is the focus of this work. Four factors influencing the baffle shape and baffles of six different shapes are provided in this research. The pressure history curves of oil liquid sloshing at the central point and on the central line, the history curves of velocity of oil liquid mass and volume, oil liquid pressure contours, and the position diagrams of free oil liquid surface were obtained and compared in fuel tanks with baffles of different shapes. Compared with the sloshing pressure of oil liquid and time-area values in fuel tanks with baffles of different shapes, the sloshing pressure of oil liquid at the central point is the smallest in fuel tank with baffles of corrugated shape, and the sloshing pressure of oil liquid on the central line is the smallest in fuel tank with baffles of straight-line shape. However, the baffles of corrugated shape are most beneficial to reduce time-area values.

But I Do Academic Anthropology!: Advocacy, Ethics, and the Politics of Research

2007 ◽  
Vol 29 (2) ◽  
pp. 20-23
Author(s):  
Rachel Adler
Keyword(s):  
United States ◽  
Political Rhetoric ◽  
The United States ◽  
The Other ◽  
The Political ◽  
Ethical Problems ◽  
Political Sphere ◽  
Political Milieu ◽  
Conducting Research ◽  
The U.S

Conducting research among immigrants in the United States can pose ethical problems not encountered by anthropologists working abroad. Research occurs, of course, in the context of a political milieu. When anthropologists are working outside of their own societies, it is easier to dissociate themselves from the political sphere. This is because foreign anthropologists are not expected to embrace the political rhetoric of societies of which they are only observers. Ethnographers inside the U.S., on the other hand, often become politicized, regardless of their academic intentions.

scholarly journals Analytical Algorithm for Oxygen Concentration of Aircraft Fuel Tank in Various Inerting Stages

2021 ◽  
Vol 11 (16) ◽  
pp. 7698
Author(s):  
Yuhao Wei ◽  
Yang Pei ◽  
Yuxue Ge
Keyword(s):  
Differential Equations ◽  
Oxygen Concentration ◽  
Fuel Tank ◽  
Conventional Model ◽  
Aircraft Fuel ◽  
Proposed Model ◽  
Fuel Tanks ◽  
Analytical Algorithm ◽  
Fire And Explosion ◽  
Derivatives Of

Ullage washing is an efficient inerting method to keep the ullage oxygen concentration under the safe value, thus reducing the hazard and loss of fire and explosion of aircraft fuel tanks. In the conventional model of ullage washing, the initial derivatives of oxygen concentration that are used to solve the differential equations are selected subjectively by researchers and the empirical select influences the accuracy of the result. Therefore, this paper proposes an analytical algorithm that can calculate the ullage oxygen concentration without selecting any initial derivative value. The algorithm is based on a fuel tank ullage washing model regarding various inerting stages. It has been experimentally validated with an average relative error of 5.781%. Moreover, sensitive analyses carried out on the proposed model show that ground-based inerting can effectively reduce the ullage oxygen, concentration in the climb phase. Increasing 5 min of pre-takeoff inerting duration can shorten the time of decreasing the ullage oxygen concentration to 9% after takeoff by 2.1 min.

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