2019 Joint Rail Conference最新文献

{"title":"The Effect of Wire Type on Cracking Propensity in Prestressed Concrete Prisms","authors":"Adrijana Savić, B. T. Beck, Aref Shafiei Dastgerdi, R. Peterman, K. Riding, A. Robertson","doi":"10.1115/JRC2019-1234","DOIUrl":"https://doi.org/10.1115/JRC2019-1234","url":null,"abstract":"This paper is a continuation of a previous study conducted at Kansas State University [8]. This paper demonstrates the influence of the thickness of concrete cover, compressive strength of concrete and the type of wire indentation on bond performance between steel and concrete in pre-stressed concrete ties using a consistent concrete mixture. A key objective of this research is to find the best parameters for pre-stressed concrete ties to prevent them from splitting/cracking in the field. This is very important for pre-stressed manufacturers, and especially for the railroad crosstie industry, so as to avoid failures in the field. The goal is to develop a qualification test with the capability to identify the compatible combinations of wire type and concrete mix before the ties are manufactured. A study took place at Kansas State University to understand and quantify the influence of variables such as the thickness of concrete cover, type of indents, and the compressive release strength on the bond behavior between steel and concrete. For the experimental testing three prisms with different cross sections were cast at the same time in series. Four pre-stressing wires were symmetrically embedded into each concrete prism and the spacing between wires was 2.0 inches. All prisms had the same length of 59.5in with square cross section. With the thickness of concrete cover of 3/4″ the first prism had a 3.5×3.5in square cross section, the second prism had a 5/8″ thickness of concrete cover and 3.25×3.25in square cross section and the third prism had a 1/2″ thickness of concrete cover and a 3.0×3.0in square cross section. All pre-stressing wires which were used in these tests had a 5.32mm diameter and were of different wire types. The indent pattern variations of the wire types included spiral, classical chevron shape, and the extreme case of smooth wire with no indentations. The wires were initially tensioned to 7000 pounds (31.14 KN) and then gradually de-tensioned after reaching the desired compressive strength. The different compressive (release strength) strength levels tested included 4500 psi (31.03 MPa) and 6000 psi (41.37 MPa). For this study, a consistent concrete mixture with 0.32 water-cement ratio was used for all prisms, except for prisms casted with WE wire. For these prisms a water-cement ratio of 0.38 was used. Prisms had almost identical geometrical and mechanical properties as pre-stressed concrete ties which are manufactured in the railroad industry. Each prism provided a sample of eight different independent splitting tests of concrete cover (four wire cover tests on each end) for a given release strength. All cracks which appeared after de-tensioning were observed and measured to identify the cracking field, and all sides of the prisms on the live and dead end were marked for identification. For all prisms, longitudinal strain profiles on the live end and dead end were measured along with the values of transfer lengths. The strai","PeriodicalId":287025,"journal":{"name":"2019 Joint Rail Conference","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115723396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluating the Effect of Natural Third Body Layers on Friction Using the Virginia Tech Roller Rig","authors":"Ahmad Radmehr, Karan Kothari, M. Ahmadian","doi":"10.1115/JRC2019-1292","DOIUrl":"https://doi.org/10.1115/JRC2019-1292","url":null,"abstract":"In this study, the effect of natural third body layers on the coefficient of friction and contact forces is evaluated using the Virginia Tech-Federal Railroad Administration (VT-FRA) roller rig facility. The test rig allows us to precisely control the contacting surfaces to study its effect on the wheel-rail interface forces and moments. Experiments have shown while running the tests, a slight amount of wear occurs at the running surfaces. The worn material deposits at the surface and behaves like a “natural” third-body layer at the contact, resulting in changes in traction coefficient and creep forces. The material wear and its accumulation on the running surfaces change with wheel longitudinal load and creepage.\u0000 A series of organized time-based experiments have been conducted with the running surfaces cleaned at the beginning of the test to study the effect of material wear accumulation on selected parameters including traction coefficient and creep forces over time. In order to highlight the effect of the natural third body layer on the wheel-rail contact forces, a series of experiments were conducted, in which the wheel and roller surfaces were cleaned in one case and left uncleaned in another. The results of the experiments are quite revealing. They indicate that when the running surfaces are cleaned after each test, the maximum creep force (or adhesion) is far lower than when the running surfaces are not cleaned, i.e., the natural third-body layer is allowed to accumulate at the surfaces. The results indicate that the wear debris act as a friction enhancer rather than a friction reducer.","PeriodicalId":287025,"journal":{"name":"2019 Joint Rail Conference","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130306453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Going Beyond Conventional Problem Solving for Two Railroad Wheel Defects","authors":"S. Dedmon","doi":"10.1115/JRC2019-1312","DOIUrl":"https://doi.org/10.1115/JRC2019-1312","url":null,"abstract":"Conventional problem solving is a time-honored and accepted methodology for solving many problems we encounter in our daily home and work lives. Thought processes can be linear (like a programmer) or non-linear and still use conventional problem solving skills. Conventional problem solving begins with a statement of the problem, accumulation of data, analysis of data and proposals of solutions to the problem, then testing of the hypotheses. Non-conventional problem solving often skips some of these steps, beginning with a statement of the problem and ending with possible solutions. The tools of conventional problem solving include “critical thinking”, Fool-proofing, “thinking outside the box” and Statistical techniques. Consider the first of our ancestors to figure out that harnessing fire would provide security from large predators, make food safer and easier to eat and make tools such as fire hardened tips on spears. Did all these inventions occur in one moment of genius, or did they take innumerable years to accomplish? Sometime in this process of non-conventional thinking our ancestors brought forth a new technology which ensured the survival of our species. So, how does non-conventional problem solving work? When current theory does not appear to work, then we look to the margins of our science to see if current theory continues to be ineffective. Most theories fail in the margins of the science. A classic example of conventional science failing in the margins is the general and special theory of relativity. Non-conventional problem solving offers greater opportunity for revolutionary rather than incremental, or evolutionary advancements to our science. Other examples are included in this paper. Two wheel related problems are also presented using non-conventional problem solving techniques to provide alternative solutions.","PeriodicalId":287025,"journal":{"name":"2019 Joint Rail Conference","volume":"94 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130529070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Use of Alternative Crash Pulses for Interior Fixture Design Within CEM-Equipped Passenger Rail Cars","authors":"B. Spears, E. Martinez","doi":"10.1115/JRC2019-1307","DOIUrl":"https://doi.org/10.1115/JRC2019-1307","url":null,"abstract":"Over the past several years, Carbuilders have been developing car designs that utilize Crash Energy Management (CEM) as an alternative means to demonstrate compliance with carbody structural strength requirements. With the onset of CEM designs, the CFR has been amended to include requirements for alternative compliance to carbody structure requirements (see Docket No. FRA-2013-0060, Notice No. 3, [the Final Rule]) [14]. CEM designs often utilize crush zones with the overall goal of protecting occupant volume. These designs also change the structural behavior of the car during an accident, resulting in different acceleration responses than conventional car designs. This paper seeks to compare and contrast the interior fitting strength requirements between conventional car designs and a generic CEM design. The methodology utilizes simple mathematical simulations, modeling a conventional car design and a CEM design, with outputs of the simulation consisting of car response and behavior. Results indicate that alternative compliance requirements for all tiers of CEM-designed passenger equipment should be considered for interior fixtures.","PeriodicalId":287025,"journal":{"name":"2019 Joint Rail Conference","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121964426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantification of Vertical and Lateral Loads Using Strain Gauges: Eliminating the Wheatstone Bridge","authors":"D. K. Johnson, Md. Fazle Rabbi, D. Mishra, Radim Bruzek","doi":"10.1115/JRC2019-1271","DOIUrl":"https://doi.org/10.1115/JRC2019-1271","url":null,"abstract":"Real-time measurement of vertical wheel loads applied to the rail is commonly carried out using strain gauges. One standard approach involves measurement of shear strains at the rail neutral axis, and use of the differential shear concept. Strain gauges are typically mounted on the rail neutral axis between two adjacent ties (over the crib section). A set of four strain measurements (two each, pointed at 45 degrees up and down from the horizontal) are carried out at each end of the crib section, and the measured strains are used to calculate the shear strain magnitudes; this shear strain is in turn used to calculate the applied load. In practice, the four individual strain measurements on each end of the crib (on either face of the rail) are arranged in a single Wheatstone bridge circuit. The purpose for using this common strain measurement configuration lies in the circuits’ ability to eliminate crosstalk, or strain unrelated to the load being measured, e.g. bending strain, or strain due to lateral loading, etc. This paper will propose a new measurement approach whereby eliminating this Wheatstone bridge configuration and measuring eight independent strain signals will enable direct quantification of the vertical as well as lateral load magnitudes. Instead of having to install additional strain gauges on the rail base to measure the lateral loads, the same strain gauges mounted on the rail neutral axis can be used to measure both vertical as well as lateral loads. This proposed technique will simplify the process of vertical and horizontal wheel load detection, and may increase the applicability of these circuits to detect loads in curved sections of track as well as near special track work.","PeriodicalId":287025,"journal":{"name":"2019 Joint Rail Conference","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134023204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prototyping a Conductive Polymer Steering Pad for Rail Freight Service","authors":"A. Villarreal, C. Tarawneh, M. Ontiveros, J. Aranda, Robert Jones","doi":"10.1115/JRC2019-1286","DOIUrl":"https://doi.org/10.1115/JRC2019-1286","url":null,"abstract":"The AdapterPlus™ steering pad is a polymer component on a railcar that helps to reduce stresses on the axle as a railcar rounds a curve. One railway application requires a minimum of 240 mA to be passed through the steering pad to the rail, which activates air valves that control automated cargo gates. Currently, two copper studs are inserted into the pad to provide a conductive path. However, after continuous cyclic loading caused by normal service operation, the copper studs deform, wear, and eventually lose contact between the two surfaces rendering the pad nonconductive. One proposed solution to this problem is to create a steering pad made entirely from an electrically conductive material. The University Transportation Center for Railway Safety (UTCRS) research team has successfully created a conductive nanocomposite made from vapor grown carbon nanofibers (CNFs) and a modified form of Elastollan 1195A thermoplastic polyurethane (TPU). Previous attempts to create this material were promising but failed to produce an electrically conductive specimen when injection molded. Preliminary results have shown that the new material can be injection molded to create an electrically conductive test specimen.\u0000 An injection molded insert was designed, fabricated, and incorporated into the existing steering pad design for further testing. Pressure measurement film had previously been used to find the points of maximum stress inside the pad to optimize the design of the composite insert. Characterization of the resistivity of the composite material was carried out in order to verify functionality in future iterations of this product. The resistance of the composite material is expected to be non-linear with a strong dependence on load and voltage. Conductivity tests were performed using a material testing system with a compressive load ranging from 1500 pounds to 5500 pounds. The voltage at each load was also varied between 10V to 20V and the nonlinear resistance of the material was examined. The results have shown that the CNF/TPU composite is a potential replacement for the current TPU used for the pad and, with minimal modifications, can be implemented in field service operation.","PeriodicalId":287025,"journal":{"name":"2019 Joint Rail Conference","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114491109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Probabilistic Structural Analysis of Railroad Subgrade Using Finite Element Analysis","authors":"Asif Arshid, Ying Huang, D. Tolliver","doi":"10.1115/JRC2019-1255","DOIUrl":"https://doi.org/10.1115/JRC2019-1255","url":null,"abstract":"The reliability of finite element (FE) based deterministic structural analysis of railroad trackbed has improved significantly due to ever increasing computational powers. However, the application of probabilistic methods to incorporate the material and geometric variabilities in these FE analyses is still profoundly underworked. In this study, the influence of variability in granular layers’ modulus and thicknesses values on the railroad subgrade performance have been investigated by applying probabilistic method and using a 3-dimensional FE based numerical trackbed model previously developed and validated by the authors’ research group. The influence of these factors is accounted for by changing their coefficients of variance (COV) while keeping their means constant. Preliminary results revealed that the variation in subgrade modulus is the most influential factor for subgrade performance, both in terms of progressive shear failure and excessive plastic deformations, followed by ballast modulus. Variations in depths, for the range studied, remained passive to the subgrade performance. The findings of this work is of particular significance in evaluating the subgrade performance while including the material and geometric variations, which may be caused by construction imperfections, weather changes, and/or rail operations.","PeriodicalId":287025,"journal":{"name":"2019 Joint Rail Conference","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125902749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Studying the Effect of Tangential Forces on Rolling Contact Fatigue in Rails Considering Microstructure","authors":"Mohamad Ghodrati, M. Ahmadian, R. Mirzaeifar","doi":"10.1115/JRC2019-1279","DOIUrl":"https://doi.org/10.1115/JRC2019-1279","url":null,"abstract":"In this paper, the micro-mechanical mechanisms behind the initiation and propagation of rolling contact fatigue (RCF) damages caused by the large traction forces are investigated. This study provides a three-dimensional (3D) model for studying the rolling contact fatigue in rails. Since rolling contact fatigue is highly dependent on the rail’s steel microstructure behavior, a proper 3D approach to capture the microstructure- and orientation-dependent mechanical behavior is required. A precise material model known as crystal plasticity is used for this purpose. Additionally, a cohesive zone approach is implemented to capture the crack initiation and propagation at the grain boundaries. Using the 3D finite element model which is developed for this study, we evaluate the effect of various parameters such as traction forces along the rail, and also the normal forces on the RCF response. The results reveal that the RCF cracks initiate slightly below the rail surface. These cracks start propagating toward the rail surface when the contact force is applied in repeated load cycles. The results also indicate that the depth at which RCF initiates depends on the ratio between the longitudinal traction forces and the normal loads. With larger traction forces, the cracks initiate closer, or at the rail surface, whereas larger normal loads promote the cracks initiation beneath the surface.","PeriodicalId":287025,"journal":{"name":"2019 Joint Rail Conference","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128377579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Framework for High-Speed Passenger Train Wireless Network Radio Evaluations","authors":"Subharthi Banerjee, M. Hempel, N. Albakay, Pejman Ghasemzadeh, H. Sharif","doi":"10.1115/JRC2019-1248","DOIUrl":"https://doi.org/10.1115/JRC2019-1248","url":null,"abstract":"By 2030, the United States Federal Transit Administration (FTA) plans to have High Speed Train (HST) systems deployed that span over 12,000 miles across the US.\u0000 Given the rapidly accelerating growth in consumers demand for fast on-board Internet services, there is a need for a robust and dedicated railroad wireless network architecture for their onboard and Train-to-Ground (T2G) communication systems. And while there are several potential candidates for radio access technologies (RAT), a full understanding of the benefits and drawbacks of each is still missing.\u0000 We therefore have developed and studied a simulation framework that offers railroads the ability to perform an in-depth evaluation of capabilities for different RATs in terms of interoperability, throughput, handover and bit error rate for various user-driven scenarios. The framework is capable of studying and analyzing conditions such as network performance at different train velocities, base station spacing requirements, as well as analyzing US-specific geographical or track-related architectural scenarios. Our Past experiences in researching railroad wireless solutions have shown that wireless network performance varies widely in environments like tunnels, viaducts, bridges, stations, etc. The simulator offers the network designers significant flexibility in terms of defining parameters to create simulation scenarios and obtaining a detailed understanding of network performance.\u0000 The work has created a novel, flexible and adaptable simulation framework for high-speed passenger train wireless network evaluation. The simulation tool supports 220MHz-100GHz systems for simulating LTE and 5G-New Radio (5G-NR), and it can support other technologies such as 220MHz PTC, in a time-variant channel. In this paper we present the architecture and the capabilities of the simulator with a sample scenario evaluation. The developed framework aims to support HST wireless communication designers to conduct more detailed analyses and to make more informed decisions in optimizing system deployments.","PeriodicalId":287025,"journal":{"name":"2019 Joint Rail Conference","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130779225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A High Resolution Automated Prestressing Wire Indent Profiling System for Verification of Wire-Concrete Mix Compatibility","authors":"B. T. Beck, A. Robertson, R. Peterman, Adrijana Savić, Chih-Hang Wu, K. Riding, J. Bloomfield","doi":"10.1115/JRC2019-1269","DOIUrl":"https://doi.org/10.1115/JRC2019-1269","url":null,"abstract":"It is well-known that the geometrical characteristics of the indents on prestressing wire used in the manufacture of prestressed concrete railroad ties affect the magnitude of the transfer length. In particular, it has been shown that such parameters as indent depth, indent volume and indent sidewall angle all affect transfer length, with indent volume being a major influence. Previous research has shown that the larger the indent volume, the shorter the transfer length.\u0000 For full load bearing capacity, it is important that the transfer length not exceed the distance to the rail seat. Consequently, transfer length has been identified as a key diagnostic parameter for evaluating the load bearing capability of prestressed concrete railroad crossties. Furthermore, it has been proposed for use as a valuable quality control parameter.\u0000 Ongoing research, as well as previously published research results, also indicates that the geometry of the prestressing wire indents plays a major role in the formation of cracking. This is particularly important in the manufacture of concrete ties intended for high speed rail applications. Cracking and debonding of prestressing wires associated with ties in service can result in severe splitting and complete tie failure. It is therefore not sufficient to guarantee a safe transfer length alone, without consideration of the cracking propensity. The wire specifications in standard ASTM A881 are intended to promote quality prestressed railroad tie behavior; however, the detailed causes of cracking and splitting, and the specific indent features that are responsible, are not well-known from a quantitative perspective.\u0000 Until recently, inspection of prestressing wire indent properties consisted of sampling a few indents from a small segment of wire, providing very limited statistical information on wire indent properties. To address this deficiency, a high-resolution automated non-contact optical wire indent scanning system has been developed for completely and rapidly characterizing all relevant indent geometrical parameters. The system is capable of measuring large segments of wire to yield statistically significant samples of all relevant indent parameters including indent depth, indent width, indent sidewall angle, indent pitch, and indent volume. The current state-of-the-art in this system development, along with some new insights based on recent indent scanning results, will be presented. This system represents a valuable tool to aid in identifying the key indent geometrical features related to cracking. The overall goal is to quickly assess critical indent parameters, so as to ensure high-quality bond and eliminate in-track tie splitting failures.","PeriodicalId":287025,"journal":{"name":"2019 Joint Rail Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130805608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}