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    <title>Transport Research International Documentation (TRID)</title>
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    <atom:link href="https://trid.trb.org/Record/RSS?s=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" rel="self" type="application/rss+xml" />
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    <language>en-us</language>
    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
    <image>
      <title>Transport Research International Documentation (TRID)</title>
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      <link>https://trid.trb.org/</link>
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    <item>
      <title>A Crack Growth–Based Individual Aircraft Monitoring Method Utilising a Damage Metric</title>
      <link>https://trid.trb.org/View/1623603</link>
      <description><![CDATA[The need and benefits of individual aircraft fatigue monitoring are now well established. There are broadly two fatigue damage methods employed for this purpose, namely, crack growth and stress (or strain)-life. The crack growth methods tend to provide a relative comparison between an aircraft’s usage and a baseline usage, while the strain-life methods provide a measure of the amount of fatigue life consumed against that (generally) demonstrated through a fatigue test. In this article, a new crack growth–based tracking method is described that also includes a measure of the certified fatigue life consumed. The damage model is compared against the results of an extensive coupon fatigue test programme for aluminium alloy 7050-T7451.]]></description>
      <pubDate>Fri, 26 Jul 2019 11:53:55 GMT</pubDate>
      <guid>https://trid.trb.org/View/1623603</guid>
    </item>
    <item>
      <title>Fatigue crack growth of a railway wheel</title>
      <link>https://trid.trb.org/View/1530002</link>
      <description><![CDATA[Typically, fatigue crack propagation in railway wheels is initiated at some subsurface defect and occurs under mixed mode (I–II) conditions. For a Spanish AVE train wheel, fatigue crack growth characterization of the steel in mode I, mixed mode I–II, and evaluation of crack path starting from an assumed flaw are presented and discussed. Mode I fatigue crack growth rate measurements were performed in compact tension (CT) specimens according to the ASTM E647 standard. Three different load ratios were used, and fatigue crack growth thresholds were determined according to two different procedures. Load shedding and constant maximum stress intensity factor with increasing load ratio R were used for evaluation of fatigue crack growth threshold. To model a crack growth scenario in a railway wheel, mixed mode I–II fatigue crack growth tests were performed using CT specimens. Fatigue crack growth rates and propagation direction of a crack subjected to mixed mode loading were measured. A finite element analysis was performed in order to obtain the KI and KII values for the tested loading angles. The crack propagation direction for the tested mixed mode loading conditions was experimentally measured and numerically calculated, and the obtained results were then compared in order to validate the used numerical techniques. The modelled crack growth, up to final fracture in the wheel, is consistent with the expectation for the type of initial damage considered.]]></description>
      <pubDate>Wed, 15 Aug 2018 17:29:17 GMT</pubDate>
      <guid>https://trid.trb.org/View/1530002</guid>
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    <item>
      <title>Fatigue crack analysis in a bolster of a metro train</title>
      <link>https://trid.trb.org/View/1529985</link>
      <description><![CDATA[A Metro train is one of the heavily designed structures and is capable of having long life span of 20–30 years. The occurrence of fatigue crack in the bolster of a metro train is very unusual. In this paper, a series of fatigue damage assessments on a bolster was performed to understand the possibility of fatigue crack initiation under normal operating conditions. Additionally, fatigue crack growth analysis was performed to check for the possibility of unstable crack growth during normal service operation. In the fatigue damage assessment, a minimum safety margin of 2.71 was calculated until the end of design life span of 30 years. In the crack growth analysis, operable years of 6.9 were calculated when even a 30 mm-sized-initial-crack grows to unstable crack growth. From these two results, we can conclude that the cracks found at the bolster are thought to initiate due to accidental overloading during service, and even though the 30 mm-sized-initial-crack can be detected before it brings unstable crack growth considering maintenance period of normally every 3 years.]]></description>
      <pubDate>Mon, 13 Aug 2018 22:26:47 GMT</pubDate>
      <guid>https://trid.trb.org/View/1529985</guid>
    </item>
    <item>
      <title>Evaluation of the Degradation of Concrete Ties Using Machine Vision Technology on High-Speed Rail Corridors</title>
      <link>https://trid.trb.org/View/1528233</link>
      <description><![CDATA[ENSCO, Inc. used machine vision technology to assess concrete tie degradation in Amtrak’s high-speed Northeast Corridor (NEC) over a 13-month period. The study examined three aspects of concrete tie degradation: 1) the prevalence of nonconformance types found in the assessed ties, 2) the evolution of concrete tie grades over time, and 3) the rate at which cracks in the assessed ties were found to grow. The assessment of nonconformance prevalence included cracks, chips, crumbling, and missing fasteners. The tie grading scale used in the study ranged from Grade 1–No Material Nonconformances through Grade 5–Ineffective for a population of approximately 26,000 ties and is based on a set of quantifiable parameters discussed in the report. The study’s measured crack growth rate data were used to assess whether various parameters (e.g., curvature, posted speed, tie manufacturer, etc.) have a material impact on crack growth rates. The report includes an assessment of the effectiveness of machine vision-based concrete tie inspection as well as several recommendations pertaining to concrete tie maintenance practices.]]></description>
      <pubDate>Wed, 01 Aug 2018 11:10:27 GMT</pubDate>
      <guid>https://trid.trb.org/View/1528233</guid>
    </item>
    <item>
      <title>Investigation of Rail Bolt Hole Cracks</title>
      <link>https://trid.trb.org/View/1501948</link>
      <description><![CDATA[This document is a collection of two reports on the rail bolt hole crack. Part I describes the development of a model based on beam-on-elastic foundation analysis to calculate the shear force acting at a given bolt hole location. The model includes the effects of wheel and joint bar forces, joint efficiency factor, and dynamic wheel load amplification. Also described are experiments to derive the stress intensity - bolt hole crack length relationship for rail end loading representative of the joint. The stress intensity was found to be independent of crack length for the range studied: 0.5-3 in. The model and experimental results are used to predict crack growth rates for severe traffic conditions. Part II describes analyses of three stages of bolt hole cracking: initiation, corner crack propagation, and through crack propagation up to and into the rail head. The initiation analysis makes use of the force model of the first report and results in the literature to calculate the mean and alternating stresses at the bolt hole surface. Dynamic load effects are considered and the most common occurrence of a bolt hole crack propagating away from the rail and toward the head is explained. Data are reviewed to show that fretting from the bolt or corrosion is probably necessary to initiate fatigue cracking. Estimates of the number of cycles required to propagate a corner crack to a through crack are given, including the effects of wheel eccentricity and lateral load. Several aspects of through crack propagation were considered. The stress intensity of a crack emanating from the first bolt hole due to bolt bearing is calculated for three crack lengths. Estimates of the stress intensity factors are also provided for various straight and kinked crack geometries in the rail head and along the head-web fillet. In addition, finite element analysis was performed to calculate the shear stresses distribution in a rail cross section (2D) and the stress intensity for a bolt hole crack that has entered the rail head (3D). The appendices to Part II describe the fracture appearance of  three bolt hole cracks removed from service and a fixture design that could be used to break open bolt hole cracks.]]></description>
      <pubDate>Tue, 10 Apr 2018 17:03:01 GMT</pubDate>
      <guid>https://trid.trb.org/View/1501948</guid>
    </item>
    <item>
      <title>Three Dimensional Finite Element Analysis of Rolling Contact between Wheel and Rail</title>
      <link>https://trid.trb.org/View/1486401</link>
      <description><![CDATA[The fatigue performance of the rails is affected by many factors, including service conditions, loading, mechanical properties, environment factors, and manufacturing processes. In this paper, the investigation on wheel-rail to identify the initial damages caused by Rolling Contact Fatigue (RCF) cracks and the location that experienced damages is presented. UIC 54kg rail (grade 900A) was used as the model in three dimensional (3D) finite element contact analysis. The fatigue crack growth on wheel-rail was carried out by considering the Hertz contact pressure. The finite element analysis results show that maximum stress concentration zone was between the wheel-rail surface (rail inside curve gauge corner) and it is above the yield stress limit for wheel-rail steel. Fatigue crack propagation within a depth affected stress concentration region was predicted. The stress intensity factors (SIF) for mode I, mode II and mode III fracture were plotted from ANSYS simulation. Three types of fracture modes were affected the UIC54kg rail Steel to fail or develop initial failure when the crack propagation exceeds 5 mm.]]></description>
      <pubDate>Wed, 29 Nov 2017 14:54:18 GMT</pubDate>
      <guid>https://trid.trb.org/View/1486401</guid>
    </item>
    <item>
      <title>Plastic Pipe Failure, Risk, and Threat Analysis</title>
      <link>https://trid.trb.org/View/1478823</link>
      <description><![CDATA[The three primary failure modes that may be exhibited by polyethylene (PE) gas pipe materials were described in detail. The modes are: ductile rupture, slow crack growth (SCG), and rapid crack propagation (RCP). Short term mechanical tests were evaluated for usefulness in determining the relative resistance of PE materials to SCG failures. Long-term hydrostatic stress-rupture test data were used with various models to predict the remaining life expectancy of a few older PE materials under specific field conditions. More than 50 field failures were classified by cause. Small scale steady state (S-4) testing was conducted on six large diameter PE materials to determine the critical pressure and/or the critical temperature.]]></description>
      <pubDate>Mon, 07 Aug 2017 12:32:32 GMT</pubDate>
      <guid>https://trid.trb.org/View/1478823</guid>
    </item>
    <item>
      <title>Achieving Maximum Crack Remediation Effect from Optimized Hydrotesting</title>
      <link>https://trid.trb.org/View/1472016</link>
      <description><![CDATA[This project developed and validated models that will allow the industry to predict the overall benefits of hydrotests. Such a prediction is made with a consideration of various characteristics of a pipeline including the type of operation, stage of cracking, environmental susceptibility, steel metallurgy, and operation history. When hydrotesting is necessary, the model will help operators select the parameters that would generate the most effective crack remediation.]]></description>
      <pubDate>Mon, 10 Jul 2017 10:57:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/1472016</guid>
    </item>
    <item>
      <title>Measurements of Fatigue Crack Growth Rates of the Heat-Affected Zones of Welds of Pipeline Steels</title>
      <link>https://trid.trb.org/View/1470927</link>
      <description><![CDATA[Pipelines are widely accepted to be the most economical method for transporting large volumes of hydrogen, needed to fuel hydrogen-powered vehicles. Some work has been previously conducted on the fatigue crack growth rates of base metals of pipeline materials currently in use for hydrogen transport and on pipeline materials that may be used in the future. However, welds and their heat-affected zones are oftentimes the source and pathway for crack initiation and growth. The heat-affected zones of welds can exhibit low resistance to crack propagation relative to the base metal or the weld itself. Microstructural irregularities such as chemical segregation or grain-size coarsening can lead to this low resistance. Therefore, in order to have adequate information for pipeline design, the microstructures of the heat-affected zones must be characterized, and their mechanical properties must be measured in a hydrogen environment. With that in mind, data on the fatigue crack growth rate is a critical need. The authors present data on the fatigue crack growth rate of the heat-affected zones for two girth welds and one seam weld from two API 5L X52 pipes. The materials were tested in hydrogen gas pressurized to 5.5 MPa and 34 MPa at a cyclic loading rate of 1 Hz, and an R ratio of 0.5.]]></description>
      <pubDate>Mon, 03 Jul 2017 11:58:09 GMT</pubDate>
      <guid>https://trid.trb.org/View/1470927</guid>
    </item>
    <item>
      <title>The Effect of Pressurized Hydrogen Gas on the Fatigue Properties of Welds in X52 and X70 Pipelines</title>
      <link>https://trid.trb.org/View/1469955</link>
      <description><![CDATA[This report details the results of measurements of fatigue crack growth of welds in X52 and X70 pipeline steels, predominantly at a hydrogen gas pressure of 5.5 MPa. Data acquired at 34 MPa are included for comparison where available. The goal of the study was to address the primary concern voiced by the ASME B31.12 committee on Hydrogen Piping and Pipelines. Specifically, the heat-affected zones (HAZs) and the welds may behave differently in a hydrogen-gas environment from the base metals. In order to compose a code that ensures the safety of the general public, measurement of fatigue properties of these regions must be performed. Since the weld material is either different from the base metal in composition or microstructure (or both), the committee decided that welds need to be evaluated for fatigue crack growth rate (FCGR). Furthermore, since the weld metal has more varied microstructure and has higher residual stresses compared to the base metal, hydrogen may preferentially migrate to this region. This work is intended to contribute to possible modifications to the code that provide a basis for pipeline design based upon fatigue, the most likely failure mode of a pipeline. A research plan was developed that included tests to assess the integrity of both seam (where relevant) and girth welds in pipelines, specifically in X52 and X70 steels. This work included measurements of FCGR in X52 and X70 welds at a load ratio of 0.5, loading frequency of 1 Hz, and hydrogen gas pressure of 5.5 MPa. Four girth welds and two seam welds were tested. Welds and HAZs from four pipes showed hydrogen-assisted fatigue crack growth of the same order of magnitude as the base metal at hydrogen gas pressures of 5.5 MPa and 34 MPa. In general, the girth welds exhibited a lower FCGR than the base metal. Seam welds and the HAZ from the girth weld of the vintage X52 pipe tended to have higher FCGRs than the base metal. The presence of untempered martensite in the HAZ associated with the vintage X52 girth weld is the likely source for the higher FCGR. Some anomalous behavior was seen in fatigue, mostly with girth welds and their associated HAZs. For a complete enough understanding of fatigue crack growth behavior to model and include in a code modification, more testing and modeling of these welds and HAZs are needed.]]></description>
      <pubDate>Mon, 26 Jun 2017 17:41:55 GMT</pubDate>
      <guid>https://trid.trb.org/View/1469955</guid>
    </item>
    <item>
      <title>Effects of Hydrocarbon Permeation on Plastic Pipe Strength and Fusion Performance</title>
      <link>https://trid.trb.org/View/1470031</link>
      <description><![CDATA[The objective of this project was to develop methods to be used by any plastic testing laboratory to quantify the effects of hydrocarbon permeation on: 1) the fusibility of plastic pipe; 2) the life expectancy of existing fused joints that have been subjected to hydrocarbon permeation; 3) the Hydrostatic Design Basis (strength) of plastic pipe, and 4) the impact on slow crack growth. A secondary objective was to determine and validate current practices of local distribution companies (LDC) in mitigating hydrocarbon permeation on their in-field pipe. In the course of this project several test methods have been explored and developed to quantify the effect of heavy hydrocarbon permeation on polyethylene pipe and the butt-fusion process.]]></description>
      <pubDate>Mon, 26 Jun 2017 17:41:55 GMT</pubDate>
      <guid>https://trid.trb.org/View/1470031</guid>
    </item>
    <item>
      <title>Mechanistic evaluation of fatigue cracking in asphalt pavements</title>
      <link>https://trid.trb.org/View/1464042</link>
      <description><![CDATA[Over the last several decades, significant research has been conducted to predict the fatigue cracking performance of asphalt pavements. Recently, the simplified viscoelastic continuum damage (S-VECD) model was developed as an efficient method of characterising the fatigue performance of asphalt mixtures under a wide range of loading conditions. Two important material properties that can be determined from the S-VECD model are the damage characteristic curve that defines how damage evolves in a specimen and the energy-based failure criterion that defines when the specimen fails. These two material functions are unique for a given mixture regardless of temperature, mode of loading, stress/strain amplitude and loading history. This study presents the application of the Layered Viscoelastic Critical Distresses (LVECD) programme to predict the fatigue performance of 18 pavement sections from different locations in the United States and Canada. The capability of the LVECD programme to capture crack initiation, crack propagation and damage in the pavement sections is investigated by comparing the simulation results with field observations. This study found reasonable agreement in trends between the damage growth throughout the pavement cross sections as predicted by the LVECD programme and the surface crack growth as evidenced by field observations.]]></description>
      <pubDate>Wed, 10 May 2017 13:06:14 GMT</pubDate>
      <guid>https://trid.trb.org/View/1464042</guid>
    </item>
    <item>
      <title>Energy-Based Mechanistic Approach to Characterize Crack Growth of Asphalt Mixtures</title>
      <link>https://trid.trb.org/View/1259194</link>
      <description><![CDATA[Fatigue cracking is a common distress in asphalt pavements, but most existing models to predict its growth are generally empirical or phenomenological in nature. To fill this gap, this paper aims at developing an energy-based mechanistic approach to model the fatigue crack growth in asphalt mixtures. The core of this approach is establishing the energy balance equations between the apparent energy of the bulk specimen and the true energy of the intact material. A controlled-strain repeated direct tension (RDT) test is used to generate fatigue cracking damage in asphalt mixtures. The true stresses, true strains, and true pseudostrains are simulated through the force equilibrium and energy balance equations. The true stress in a damaged asphalt mixture is found to be the driving force for crack growth; the crack growth in turn aggravates the localization of the true stress/true strain. The ratio of the true stress and the apparent stress in a damaged asphalt mixture is used to calculate the damage density. The evolution of the damage density with repeated loading demonstrates the development of fatigue cracking in the asphalt mixture. In addition to modeling fatigue cracking in asphalt mixtures, the energy-based mechanistic approach developed in this paper can be used with a wide range of tests to predict crack growth of different types of materials because of its mechanical nature.]]></description>
      <pubDate>Tue, 03 Sep 2013 12:29:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/1259194</guid>
    </item>
    <item>
      <title>Assessment of Fatigue Cracks in Rails</title>
      <link>https://trid.trb.org/View/1255245</link>
      <description><![CDATA[The fatigue behaviour of cracks at the foot region of a rail subjected to bending load has been investigated. Depending on the position of initiation of a small semi-elliptical surface crack in a rail, the crack front changes shape during propagation to failure due to the large variation of the stress intensity factor (SIF) from point to point round the crack front due to differences in the local stress field as each point round the crack front lies at different distances from the neutral axis of the rail. This condition implies a variable crack growth rate that transforms the crack front shape during fatigue crack propagation. SIF values have been estimated by means of both the finite element method and analytical solutions derived for a semi-elliptical crack in a finite rectangular cross-section beam. The SIF value predictions obtained with the two methods show good agreement suggesting that the analytical solutions can be used for a rapid assessment of the severity of a flaw in a rail. A predictive model for crack growth has been derived for an initial small crack at an initiation point at the foot/web corner of a rail tested under four point bending fatigue in the laboratory, showing a reasonably good prediction of both the shape and size of the crack at failure when compared with experiment.]]></description>
      <pubDate>Wed, 28 Aug 2013 12:32:35 GMT</pubDate>
      <guid>https://trid.trb.org/View/1255245</guid>
    </item>
    <item>
      <title>Analysis of Fatigue and Fracture of Hot Mix Asphalt Mixtures</title>
      <link>https://trid.trb.org/View/1252380</link>
      <description><![CDATA[An accurate assessment of the fatigue life of hot mix asphalt (HMA) mixtures depends on the criteria used in the fatigue analysis. In the past, various studies have been conducted on crack initiation and crack propagation of the HMA mixtures. Most of these studies were focused on the beam samples with or without a sawed crack at the bottom. This paper presents and discusses two different fatigue life criteria for two-dimensional problems represented by cylindrical samples. One criterion is based on the rate of accumulation of the tensile horizontal plastic deformation (HPD) as a function of the number of load repetitions. The second criterion is based on fracture mechanics, stress intensity factor, and the rate of crack growth with respect to the number of load repetitions. It was found that, because of three-dimensional nature of the crack growth in cylindrical samples, the Paris' law was violated. It is shown that the rate of crack growth criterion provides higher values of fatigue life relative to the rate of accumulation of HPD criterion. Although a trend could be established among the fatigue lives obtained by using the two criteria, it was found that the fatigue lives obtained from the rate of accumulation of HPD were consistent and based on the actual measurement of HPD for HMA mixtures.]]></description>
      <pubDate>Mon, 24 Jun 2013 11:10:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/1252380</guid>
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