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    <title>Transport Research International Documentation (TRID)</title>
    <link>https://trid.trb.org/</link>
    <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>
      <url>https://trid.trb.org/Images/PageHeader-wTitle.jpg</url>
      <link>https://trid.trb.org/</link>
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    <item>
      <title>Dynamic response analysis of ultra-long propulsion shafting under zigzag maneuvers</title>
      <link>https://trid.trb.org/View/2737337</link>
      <description><![CDATA[Traditional shafting alignment typically neglects transverse maneuvering loads. This study proposes a novel multi-physics co-simulation framework to thoroughly analyze the dynamic response of ultra-long propulsion shafting systems during zigzag maneuvers. By combining the Abkowitz mathematical model and Multiple Reference Frame techniques, transient hydrodynamic loads at the propeller are extracted and mapped onto a three-dimensional finite element model. The results clearly indicate that a twenty-degree zigzag maneuver induces a stern-swing amplification effect, generating extreme alternating transverse forces up to 58 kN that primarily govern structural alternating stress amplitudes. Interestingly, the study reveals a counter-intuitive peak response phenomenon: smaller rudder angles lead to higher maximum equivalent stresses. During a five-degree maneuver, the maximum equivalent stress climbs to 20.42 MPa, driven by high baseline longitudinal thrust sustained by high-speed inflow since the ship speed does not decay significantly. Conversely, under a twenty-degree maneuver, the maximum stress decreases to 18.47 MPa; despite massive transverse impacts, the longitudinal thrust decays sharply alongside the ship speed. Due to cantilever beam effects, these stresses consistently concentrate at the stepped shaft transition fillet near the aft stern tube bearing. Therefore, non-linear coupling between transient transverse loads and longitudinal thrust attenuation requires vital core boundary conditions.]]></description>
      <pubDate>Wed, 12 Aug 2026 14:59:37 GMT</pubDate>
      <guid>https://trid.trb.org/View/2737337</guid>
    </item>
    <item>
      <title>SEAHIVE Project Data [supporting dataset]</title>
      <link>https://trid.trb.org/View/2736749</link>
      <description><![CDATA[The uploaded file contains the raw data from the structural tests I conducted on the SEAHIVE model. These tests were performed to evaluate the structural integrity and resilience of the SEAHIVE design under various conditions. The results, along with the corresponding photos and detailed analysis in Excel format, are available in the provided link for further review and interpretation.]]></description>
      <pubDate>Tue, 11 Aug 2026 16:57:16 GMT</pubDate>
      <guid>https://trid.trb.org/View/2736749</guid>
    </item>
    <item>
      <title>Dynamic spatio-temporal distribution of the internal environment in an evacuated tube transportation system: A study based on a practical experimental platform under construction</title>
      <link>https://trid.trb.org/View/2694576</link>
      <description><![CDATA[Aerodynamic phenomena in evacuated tube transportation systems can induce severe deviations in internal environmental parameters, which in turn may give risks to both transportation safety and the structural integrity of the tube. This study aims to reveal the dynamic spatiotemporal changes in the internal environment of an experimental platform, specifically, the pressure and temperature variations inside the tube by employing the Shear Stress Transport k-ω (SST k-ω) model combined with dynamic mesh technology. The established model is based on an unfinished test platform to guide subsequent experimental work. In this study, the changes in pressure, temperature, and piston wind both inside the tube and on its inner wall are analyzed, considering the complex phenomena that occur throughout the entire operational process. The results indicate that when researching the internal environment of evacuated tube transportation systems, the impact of radiation must be incorporated into the analysis. And throughout the operational process, the pressure distribution inside the tube and on its inner wall remains relatively uniform. In contrast, due to the presence of a temperature boundary layer, the temperature distribution on the tube wall varies much more gently than that in the tube's internal flow field. It is noteworthy that the formation and dissipation of shock waves lead to drastic changes in the flow field surrounding the train. The choked flow front exhibits steeper pressure and temperature gradients. Additionally, the aforementioned complex phenomena also affect the piston wind inside the tube, resulting in temporal variations in its direction.]]></description>
      <pubDate>Mon, 10 Aug 2026 16:51:31 GMT</pubDate>
      <guid>https://trid.trb.org/View/2694576</guid>
    </item>
    <item>
      <title>Enhancing railway subgrade stability using a prestressed reinforcement structure</title>
      <link>https://trid.trb.org/View/2703899</link>
      <description><![CDATA[Poor railway subgrades typically exhibit significant settlements and stability issues, leading to compromised service performance and increased maintenance demands. To address such a troublesome, a novel prestressed structure (PS) was proposed to enhance railway subgrade performance. This study investigates the use of PS to improve the bearing capacity of railway subgrades by conducting two series of 1:5 scale model plate load tests, aimed at capturing differences in load-deformation behaviour. The two tests consist of the double square plate load test (DS-PLT) and the rectangular plate load test (R-PLT). The test indicators include settlement on the top surface of the subgrade and lateral deformation of the subgrade slope. Results from the two PLTs indicate that both the PS and the pretension force in the steel bars contribute effectively to enhance subgrade resistance to deformation, with the improvement becoming more pronounced as the applied plate load increases. Subsequently, based on the results of the R-PLTs, calibrated three-dimensional FEMs were employed to model various PS configurations for subgrades, examining the effects of PS installation locations, the number of PS rows, prestress levels (or reinforcement pressures), and steel bar’s diameters on the subgrade load-deformation responses with high reliability. Practical recommendations for optimizing PS layout were proposed. Finally, based on both experimental and numerical results, the reinforcing mechanism of the prestressed subgrade was discussed.]]></description>
      <pubDate>Mon, 10 Aug 2026 11:16:49 GMT</pubDate>
      <guid>https://trid.trb.org/View/2703899</guid>
    </item>
    <item>
      <title>Analysis of the Nonlinear Behavior of the Composite Helicopter Horizontal Centralwing Skin</title>
      <link>https://trid.trb.org/View/2732293</link>
      <description><![CDATA[Test results of the composite helicopter horizontal central-wing under symmetric and unsymmetric loads showed that the strain value of the lower skin would turn from negative to positive, showing a nonlinear behavior. FEM results of the linear and nonlinear analytical approach showed a great difference. The strain value of the lower skin remains negative and decreases linearly when using a linear FEM analysis. The strain value of the lower skin would turn from negative to positive when a nonlinear FEM analysis is applied, and this result agrees well with the test results. Besides, the results of the FEM buckling analysis showed that the buckling load of the lower skin is considerably higher than the value at which the skin would show a nonlinear behavior. Therefore, the specific behavior is a result of the nonlinear property of the structure, not buckling.]]></description>
      <pubDate>Sat, 08 Aug 2026 18:07:48 GMT</pubDate>
      <guid>https://trid.trb.org/View/2732293</guid>
    </item>
    <item>
      <title>Review of Aircraft Crash Structural Response Research</title>
      <link>https://trid.trb.org/View/2731616</link>
      <description><![CDATA[A review of aircraft crash structural response research has been carried out by studying the literature, discussions with researchers working in that area, and visits to facilities/personnel involved in conducting and/or monitoring aircraft crash structural response investigations. Aircraft structures consisting of conventional built-up metallic construction and those consisting of advanced composite materials were of interest. The latter type of material and construction is of particular interest since their use is expanding rapidly, and crashworthiness of such structures is of increasing importance. Some recent theoretical and experimental studies of the behavior of composite-material structures subjected to severe static, dynamic, and/or impact conditions are noted. Such topics as crashworthiness testing of composite fuselage structures, the impact resistance of graphite and hybrid configurations, and the effects of elastomeric additives on the mechanical properties of epoxy resin and composite systems are reviewed. The principal theoretical methods for predicting the nonlinear transient structural responses of severely loaded structures are reviewed. Available lumped-mass and finite-element computer programs tailored to aircraft crash response analysis are noted. A review is made of some current and planned research to investigate experimentally the mechanical failure, post failure, and energy-absorbing behavior of a sequence of composite-material structural elements and structural assemblages subjected to static loads or to simulated crash-impact loads.]]></description>
      <pubDate>Sat, 08 Aug 2026 12:14:31 GMT</pubDate>
      <guid>https://trid.trb.org/View/2731616</guid>
    </item>
    <item>
      <title>Operational Modification of Traditional Boat Tools: Case Study of a Phinisi Ship Using Adaag Standards and ISO 21542</title>
      <link>https://trid.trb.org/View/2742720</link>
      <description><![CDATA[Traditional Indonesian Phinisi vessels remain iconic in heritage maritime tourism, yet their design excludes individuals with mobility impairments due to steep access points and narrow corridors. This study aimed to develop operational modifications for traditional Phinisi boat tools using a structured ship design methodology, adopting the Spiral Ship Design Method across four iterative phases: concept design, preliminary design, contract design, and detail design. CAD-based modeling and ergonomic simulation guided the redesign of the vessel's main, upper, and top decks to comply with international accessibility standards, including ADAAG and ISO 21542. Features introduced include widened doorways (= 815 mm), anti-slip ramps (1:12 incline), ergonomic handrails (860–920 mm height), and integrated hydraulic vertical lifts. Finite Element Method (FEM) analysis verified structural integrity under static and dynamic load cases, confirming safety factors ranging from 1.42 to 3.31 across all modified structural elements. Stability analysis demonstrated that all retrofit configurations-maintained compliance with the IMO International Stability (IS) Code, with the full retrofit yielding a metacentric height (GM) of 0.41 m, well above the 0.15 m minimum. Stakeholder validation involving tourism operators, naval architects, and wheelchair users confirmed the practicality and cultural acceptability of the design. This study offers a replicable model for inclusive retrofitting of traditional wooden boats, advancing sustainable and accessible maritime tourism aligned with global inclusivity goals.]]></description>
      <pubDate>Thu, 06 Aug 2026 09:08:21 GMT</pubDate>
      <guid>https://trid.trb.org/View/2742720</guid>
    </item>
    <item>
      <title>Static–Dynamic Coupling Optimization Design of Battery Enclosure under Multigradient Loading Based on a High-Fidelity Digital Twin Model</title>
      <link>https://trid.trb.org/View/2701119</link>
      <description><![CDATA[Although digital twin high-fidelity models have demonstrated accuracy and effectiveness in battery system condition monitoring, performance prediction, and other fields, they have not yet been deeply integrated into the static–dynamic coupled structural optimization of battery enclosures. Taking the digital twin as a breakthrough engine, this study first conducts risk assessment on the enclosure under multigradient loading conditions based on a high-fidelity digital twin model iteratively corrected by the multiobjective particle swarm optimization (MOPSO) algorithm (maximum relative error not exceeding 8%). Then, it optimizes the topography of the upper cover with the goal of maximizing the bending and torsional modal frequencies, applies opposing compressive forces along the X- and Y-axes to the bottom plate, and reversely derives the optimal arrangement of reinforcing beams based on the distribution characteristics of reinforcing ribs output from the optimization. Finally, to fully tap the design potential, multiobjective optimization on the newly designed enclosure is conducted in combination with the sequential quadratic programming (SQP) algorithm. The results showed that after optimization, the total mass of the battery enclosure was reduced by 10.88%, its crush resistance under a 100-kN load was improved by 24.5%, the first-order bending mode was increased by 12.3%, and the second-order torsional mode was increased by 13.9%, providing a more targeted and practical technical path for the design of battery enclosures for electric vehicles.]]></description>
      <pubDate>Wed, 05 Aug 2026 09:14:01 GMT</pubDate>
      <guid>https://trid.trb.org/View/2701119</guid>
    </item>
    <item>
      <title>Structural responses of offshore multi-body floating bridges under different connection conditions</title>
      <link>https://trid.trb.org/View/2738869</link>
      <description><![CDATA[Multi-body floating bridges are an economic solution to connect adjacent islands across deep straits. The design of connectors is crucial for the safety and reliability of multi-body floating bridges. This study aims to investigate the impact of various connectors (rigid, rubber, hinged, and flexible) on the hydrodynamic response of offshore multi-body floating bridges, as well as on the structural responses of connectors. A multi-body floating bridge is designed and numerically modelled with two-pontoon floating units interconnected by connectors. Four different connector types are represented by applying the proper stiffness and restraints between neighbouring floating units. The time-domain hydrodynamic response of floating bridges is simulated under the environmental loads of the East China Sea. The impacts of different connector types and wave headings on the connector responses are compared and analysed. Subsequently, the detailed finite element models of connectors are developed based on FEM to evaluate the maximum stress and fatigue life. The results show that, compared with the rigid connection, the flexible connection increases the translational motion response of the floating units by approximately 30%, and almost double the roll amplitude. The peak axial force of the flexible connector is about twice as much as that of the rubber connection. When the incident wave angle increases from 0° to 90°, both the peak axial force and the bending moment about the local Z-axis decrease by approximately 50%. Fatigue assessment shows that the annual fatigue damage of the rigid connection is 0.0470, while that of the rubber connection is 0.0154. Based on all the comparisons, rubber connections are recommended due to its excellent comprehensive performance against fatigue damage.]]></description>
      <pubDate>Tue, 04 Aug 2026 14:33:54 GMT</pubDate>
      <guid>https://trid.trb.org/View/2738869</guid>
    </item>
    <item>
      <title>Financing constraints and structural drivers of maritime decarbonization</title>
      <link>https://trid.trb.org/View/2737146</link>
      <description><![CDATA[Maritime transport accounts for nearly 3% of global greenhouse gas emissions, yet decarbonization research often assumes that stronger regulation will automatically accelerate transition. This study examines how financial, technological, and regulatory conditions jointly shape the feasibility of capital mobilization in shipping. Using integrated factor extraction, perception-based causal mapping (DEMATEL), and Importance–Performance Analysis (IPA), the study identifies perceived structural interdependencies influencing maritime decarbonization finance. The results suggest that financial viability, liquidity conditions, risk-sharing mechanisms, and digital verification infrastructure are perceived as key enabling conditions, while regulatory and stakeholder factors tend to operate as reinforcing elements. Rather than indicating regulatory insufficiency, the findings highlight the interdependence between policy signals and financial-system readiness. This study contributes by integrating structural diagnostics with prioritization logic and provides policy-relevant insights for sequencing interventions in capital-intensive transport systems.]]></description>
      <pubDate>Mon, 03 Aug 2026 09:23:53 GMT</pubDate>
      <guid>https://trid.trb.org/View/2737146</guid>
    </item>
    <item>
      <title>Investigation into structural optimisation techniques for large wave-piercing catamaran vessels</title>
      <link>https://trid.trb.org/View/2696999</link>
      <description><![CDATA[This study investigates the structural optimisation of large catamarans through alterations to the plate thickness and overall vessel height to reduce weld length and vessel mass. The manufacturing time and associated labour cost for welding a vessel is a significant cost component, hence minimising the weld length is a focus to minimise overall cost. Additionally, reducing overall vessel mass reduces material costs while also allowing additional payload or reduction of powering requirements. Larger vessels are exposed to larger loads, scaling non linearly with respect to length, hence requiring an in-depth investigation to optimise. A comparison of multiple vessels is utilised to determine a relationship between vessel length and optimal height, resulting in a general height reduction from typical vessel design in the upper strength deck (portal top), and a corresponding reduction of mass. The optimal vessel height is determined based on traditional vessel scantling, and corresponding weld lengths is discussed. Geometrical changes are also considered in order to reduce weld length in key areas of the vessel. Overall, height optimisation yields a mass reduction of 8.9%, with weld length reductions of 8.3% in the keel flat and 46.8% in the portal top region.]]></description>
      <pubDate>Fri, 31 Jul 2026 09:23:49 GMT</pubDate>
      <guid>https://trid.trb.org/View/2696999</guid>
    </item>
    <item>
      <title>Reliability Assessment of a Multi-response Bridge System Considering Climate Change Effects on Wind and Wave Loads</title>
      <link>https://trid.trb.org/View/2687102</link>
      <description><![CDATA[This study proposes a novel reliability analysis framework to efficiently evaluate the long-term reliability of multi-response structures under climate change. In this framework, an error-controlled multi-input-multi-output surrogate model is developed based on a support vector regression method, which can propagate uncertainties of structural parameters to responses with satisfactory accuracy while minimising computational costs. By integrating the copula theory and reliability assessment method, the multi-response failure probability is derived, considering both correlations between responses and uncertainties of performance thresholds. In addition, future data on wind climate are collected to account for climate change, and a neural network model is trained using historical and simulated data to predict future wave heights. The framework is then applied to a long-span cable-stayed and suspension bridge system as a case study. Analysis results demonstrate that a comprehensive multi-responses reliability analysis, which considers correlations between responses, can reflect the overall fragility of structures and prevent the underestimation of structural risk. Though the trends in structural failure probabilities vary depending on the climate model, climate change significantly influences structural risk assessment. This study provides a novel perspective for the structural reliability assessment of complex structures.]]></description>
      <pubDate>Fri, 31 Jul 2026 09:23:48 GMT</pubDate>
      <guid>https://trid.trb.org/View/2687102</guid>
    </item>
    <item>
      <title>Structural Redundancy Analysis for Continuous Steel Two-Girder Bridges: Evaluation of Capacity and Failure Modes</title>
      <link>https://trid.trb.org/View/2736658</link>
      <description><![CDATA[This study presents structural redundancy evaluations of three two-girder steel bridge systems using finite element analysis to assess their capacity and behavior under fracture conditions. Following AASHTO System Redundant Members (SRM) Guide Specifications, detailed three-dimensional finite element analysis (FEA) models were developed in ABAQUS to simulate member fractures at critical locations and evaluate bridge responses under Redundancy I and II load combinations. The analysis includes two-girder bridges using geometries typical of real bridge applications. Multiple fracture scenarios across different spans were evaluated to identify controlling limit states and failure modes. Results demonstrate that two-girder systems may have redundancy challenges as a result of limited load sharing between intact and fractured girders. This limitation results from low torsional stiffness and relatively flexible lateral bracing and floor beams, which severely restrict load redistribution. When one girder fractures, the remaining intact girder carries substantially increased loads, causing the fractured girder to behave as a cantilever beam. The controlling failure mode was identified as buckling at section changes near piers on fractured girders, with high displacement differences between intact and fractured girders. These behaviors may reduce reserve capacity below Redundancy I and II thresholds. Analysis revealed that the evaluated two-girder bridges did not meet SRM qualification requirements because of inadequate load transfer mechanisms between the two main load-carrying members. This research provides bridge engineers with critical guidance on the need for careful evaluation when two-girder systems are evaluated for redundancy performance.]]></description>
      <pubDate>Thu, 30 Jul 2026 09:59:20 GMT</pubDate>
      <guid>https://trid.trb.org/View/2736658</guid>
    </item>
    <item>
      <title>Investigation of Acoustic Fill Effect of a Launch Vehicle Payload Fairing</title>
      <link>https://trid.trb.org/View/2712144</link>
      <description><![CDATA[The payload fairing of a launch vehicle is subjected to extremely high acoustic loads, with peak levels occurring during lift-off and transonic aerodynamic regimes. The external acoustic field penetrates the fairing, producing intense internal sound pressure levels that can challenge the integrity of spacecraft components. Accurate characterization of the vibroacoustic behavior of the payload fairing and its enclosed cavity is therefore essential to ensure spacecraft survivability. The internal acoustic field is governed by the coupled dynamics of the fairing structure and the spacecraft configuration, making it critical to quantify the acoustic environment for different payload arrangements. This study presents a detailed vibroacoustic analysis of a payload fairing with multiple spacecraft configurations to evaluate the resulting internal sound pressure distribution. Vibroacoustic finite element analysis is employed in the low frequency range, while statistical energy analysis is utilized for mid and high frequency ranges. Representative models are developed, and the predicted structural and acoustic responses are validated against experimental acoustic test measurements. The validated models are subsequently extended to other spacecraft configurations to perform sensitivity studies. The influence of various parameters on the internal sound pressure levels is assessed, and the resulting perturbations across frequency bands are quantified. The outcome of this study provides a comprehensive understanding of the internal acoustic environment within payload fairing, aiding in the specification of qualification acoustic test level for spacecraft.]]></description>
      <pubDate>Wed, 29 Jul 2026 14:10:03 GMT</pubDate>
      <guid>https://trid.trb.org/View/2712144</guid>
    </item>
    <item>
      <title>Thermo-Structural Analysis of Grid Fins for Re-Entry Modules</title>
      <link>https://trid.trb.org/View/2712138</link>
      <description><![CDATA[Grid fins are non-conventional aerodynamic lifting and control surfaces which are made of a frame supporting lifting surfaces positioned in the form of a lattice structure. Grid fins are also called as lattice fins and are used as control surfaces in launch vehicles, crew escape systems, missiles etc. to achieve static stability. Each panel of the grid fin acts as fin and it produces force which increases stability of the vehicle. For a crew escape system module, grid fins are used as a passive aerodynamic control surfaces to achieve static stability. Grid fins are positioned at the end of crew escape system module to provide required static margin by increasing moment arm. In contrast to conventional fins, grid fins incorporate a distinctive waffle-like pattern or grid pattern configuration, offering superior aerodynamic performance in supersonic regimes and enabling compact storage in stowed position during launch followed by deployment at the time of exigency. In case of an emergency, crew escape system is activated and it will take crew escape module away from the launch vehicle during atmospheric regime. In this scenario, grid fins are deployed simultaneously along with firing of high-thrust, fast-acting solid rocket motors (SRMs) which provide the impulsive force needed for clean separation. Grid fins help to stabilize the crew escape system module by counteracting aerodynamic instabilities, especially when the module is moving through the atmosphere at high speeds. The primary structural loads acting on grid fins include deployment forces (hinge forces, locking), aerodynamic, and inertial forces. Additionally, the exhaust plumes from the firing of SRMs impinge directly upon the grid fins, generating intense thermal loads characterized by rapid temperature gradients and localized heating. The simultaneous presence of thermal and structural loads influences displacements, stresses, interface joints integrity and maximum buckling loads. Furthermore, elevated temperatures degrade mechanical properties such as yield strength, ultimate strength, and Young’s modulus, therefore a thermo-structural analysis is carried out to study the effects of these combined loads on grid fins. This paper presents typical grid fin configuration, thermo-structural formulation, finite element model details, and thermo-structural analysis results including stress margins, deformations, buckling load factors and preload variations for the maximum design load case.]]></description>
      <pubDate>Wed, 29 Jul 2026 14:10:03 GMT</pubDate>
      <guid>https://trid.trb.org/View/2712138</guid>
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