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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>
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      <title>Transport Research International Documentation (TRID)</title>
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      <link>https://trid.trb.org/</link>
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    <item>
      <title>Structure Design of the Composite Stabilizer for Civil Aircraft Based on Standards and Airworthiness Requirements</title>
      <link>https://trid.trb.org/View/2742468</link>
      <description><![CDATA[Generally, the allowable strain design is adopted for composite structures, which should ensure that the structure has sufficient strength and stiffness under the service load, and the safety margin should be greater than zero under the design load. The thesis develops a structured design for a stabilizer of civil aircraft based on standards and airworthiness requirements. The main task of this thesis is to compare the results of the all-mental structure and composite material structure of stabilizer on weight reduction at sufficient strength and stiffness.]]></description>
      <pubDate>Mon, 03 Aug 2026 15:57:02 GMT</pubDate>
      <guid>https://trid.trb.org/View/2742468</guid>
    </item>
    <item>
      <title>Dynamic and Static Optimization Design of Car-seat Structure</title>
      <link>https://trid.trb.org/View/2742464</link>
      <description><![CDATA[A car seat is one of the most critical components of passive safety. On the basis of the safety of car seats, this paper focuses on optimizing the design of the seat frame and achieving a lightweight design under various dynamic and static loading conditions. The optimization results are verified through physical experiments, which demonstrate the correctness and feasibility of the proposed design method. These experiments also provide research ideas for the optimization design of the seat structure and a certain reference value for the engineering application of the seat.]]></description>
      <pubDate>Mon, 03 Aug 2026 15:57:02 GMT</pubDate>
      <guid>https://trid.trb.org/View/2742464</guid>
    </item>
    <item>
      <title>Characterization and Fatigue Life Validation of a Mass-Reduced Drum Brake Spider Made from a Modified and Nanostructured Cast Iron</title>
      <link>https://trid.trb.org/View/2742672</link>
      <description><![CDATA[This study aimed at the characterization and validation of a drum-brake spider with mass reduction, using a new concept of a nanostructured ductile cast iron alloy. There is a well-known effort in developing lighter, more competitive products with higher safety and longer service life for brake systems. One of the approaches that enables this type of development is the use of new materials capable of delivering superior performance. Conventional ductile cast iron alloys used in brake spiders exhibit limited mechanical properties, which restricts mass reduction while still ensuring high durability in service. One way to obtain high-performance ductile cast iron alloys is through heat treatments such as austempering (ADI), which provides significant gains in mechanical strength but involves high cost and environmental liabilities due to the use of salt baths. The modified and nanostructured ductile cast iron alloy proposed in this work exhibited mechanical properties in the as-cast condition that meet the standards for ADI-treated ductile irons, showing an increase of 102% in tensile strength and 78% in yield strength compared to the baseline spider. Based on this new material, a topology optimization was performed on the baseline spider model, resulting in an optimized design with a 40% mass reduction. The model was validated using casting simulation software, and tooling was manufactured for producing the new optimized spider samples in the nanostructured ductile cast iron alloy. Static mechanical properties and microstructure were determined and approved, allowing the fatigue testing phase to proceed. Initially, the spider samples were instrumented with electrical strain gauges and subjected to the standard structural bench test known as the Chuker test, which can simulate real operating conditions of the brake system. Considering that this test requires extended bench time, an accelerated durability test was developed for the new spider model using three servo-controlled hydraulic cylinders, based on the stress levels obtained. The results from the accelerated durability bench test demonstrated superior fatigue life for the optimized spider compared to the baseline model, also validating the new testing procedure.]]></description>
      <pubDate>Mon, 03 Aug 2026 15:49:51 GMT</pubDate>
      <guid>https://trid.trb.org/View/2742672</guid>
    </item>
    <item>
      <title>Design of Telescope Support Truss Based on Topology Optimization and Size Optimization</title>
      <link>https://trid.trb.org/View/2742676</link>
      <description><![CDATA[The primary mirror support truss of large-aperture segmented telescopes, serving as a critical load-bearing component of the optical system, has its structural stability directly determining the optical imaging quality. This paper adopts a collaborative design method integrating topology optimization and size optimization to address issues, including excessive weight and unreasonable stiffness distribution in traditional support truss designs. First, based on the topology optimization theory of the Solid Isotropic Material with Penalization variable density method, topology optimization was performed on the initial truss structure using finite element simulation software, with the volume fraction as a constraint and the objective of maximizing structural stiffness to determine the optimal material distribution model. Subsequently, the truss structure was reconfigured based on the topology optimization results. Finally, the cross-sectional dimensions of the truss members were selected as optimization variables, and size optimization was performed using the NSGA-II multi-objective optimization algorithm with the objectives of minimizing structural weight and minimizing weighted compliance, while considering constraints such as stress and displacement. The results show that the optimized support truss achieves a 3.9% reduction in weight and a 35.47% decrease in elastic strain energy. This effectively meets the high-precision and lightweight design requirements for telescope support structures and provides a feasible technical solution for the design of large-aperture telescope support trusses.]]></description>
      <pubDate>Mon, 03 Aug 2026 15:42:12 GMT</pubDate>
      <guid>https://trid.trb.org/View/2742676</guid>
    </item>
    <item>
      <title>Design and Analysis of a Lightweight Offshore Gangway</title>
      <link>https://trid.trb.org/View/2742647</link>
      <description><![CDATA[During offshore wind power operation and maintenance activities, personnel transfer and boarding procedures involve numerous safety risks. is a highly effective solution for enhancing safety during ship transfers at sea. This paper designs a compact active motion-compensating lightweight gangway capable of compensating for multi-degree-of-freedom motions induced by sea waves, including roll, pitch, yaw, and heave. The structural design is first established, and based on this configuration, the output forces of the rotary electric cylinder, roll electric cylinder, and pitch electric cylinder are analyzed. A finite element method was employed to conduct a static analysis of the gangway under extreme loading conditions. Analysis of the first six modal orders revealed that the first natural frequency of the designed gangway is significantly higher than the wave frequency, thereby effectively preventing resonance phenomena. The forward transformation matrix of the gangway was simulated using the Denavit-Hartenberg (DH) method. Simulation results indicate that the working space of the lightweight gangway meets the preset motion range requirements, thereby validating the design’s feasibility. The designed compact passageway features simple operational control, high cost-effectiveness, minimal installation footprint, and low installation and control complexity, demonstrating high practicality.]]></description>
      <pubDate>Mon, 03 Aug 2026 15:42:12 GMT</pubDate>
      <guid>https://trid.trb.org/View/2742647</guid>
    </item>
    <item>
      <title>Analysis of the Hot Forming Behavior of AZ91 Magnesium Alloy</title>
      <link>https://trid.trb.org/View/2742630</link>
      <description><![CDATA[This study systematically discussed the high-temperature flow behavior of the                     Mg-Al-Zn based AZ91 alloy, which has significant application potential in modern                     aviation and automotive industries. The study was carried out in the temperature                     range of 250°C-450°C and the strain rate range of 0.001 s^−1 -0.1                         s^−1, which met the typical industrial hot processing environment.                     The analysis of high-temperature flow behavior shows that the flow stress is                     inversely proportional to the deformation temperature and is proportional to the                     strain rate. An important finding is that the constitutive model parameters are                     significantly sensitive to strain, so the strain-compensated Arrhenius                     constitutive model is developed. The model shows high accuracy in predicting the                     thermal flow stress of AZ91, and provides a valuable calculation tool for the                     simulation and optimization of forming processes in aerospace parts                     manufacturing. The results show that the extruded original microstructure                     presents slender fine grains, while the deformed sample shows a temperature                     dependent transformation: the low-temperature bimodal structure evolves into                     uniform fine grains at intermediate temperature, and the grains begin to coarsen                     at high temperature. At constant high temperature, low strain rate promotes                     grain growth and twin formation, while high strain rate refines grains and                     inhibits twins, and dislocation slip is the dominant deformation mechanism.                     These findings provide vital guidance and support for optimizing hot working                     parameters of AZ91, and are particularly important for manufacturing lightweight                     components in aircraft structures and automotive systems. The established                     process performance relationship is helpful to develop energy-saving                     manufacturing strategies for transportation equipment, and supports the goal of                     reducing weight and improving performance in the industrial field.]]></description>
      <pubDate>Mon, 03 Aug 2026 15:42:11 GMT</pubDate>
      <guid>https://trid.trb.org/View/2742630</guid>
    </item>
    <item>
      <title>Discussion on Methods for Studying Material Fatigue Life: Taking Aluminum Alloy as An Example</title>
      <link>https://trid.trb.org/View/2742501</link>
      <description><![CDATA[Fatigue design is a key common quality technology for improving the quality                     control capability of China’s automotive products. The fatigue of materials is a                     multi-scale damage evolution process. Characterizing and                     processing the large number of three-dimensional defects inside the material,                     which have different shapes and distributions, and predicting the material’s                     lifespan based on the cross-scale damage evolution mechanism, is one of the key                     technologies for fatigue optimization design. This paper discusses the                     research methods for the fatigue life of aluminum alloy materials. Firstly,                     based on the staged fatigue damage experiments, the three-dimensional defect                     features are obtained through CT scanning and reconstruction, and a defect characterization and                     processing method based on k-d tree and multi-scale feature pyramid is                     established to accurately represent the topological and geometric relationships                     of non-uniformly distributed three-dimensional defects. Secondly, a mathematical model for the evolution of                     micro-damage and macro-cracks is constructed, and the cross-scale                     transformation of defects is achieved through hierarchical and recursive                     methods, revealing the cross-scale evolution mechanism of fatigue damage in                     aluminum alloy materials. Finally, a remaining life prediction model based on                     defect information and feature weights is established through the support vector                     regression algorithm (SVR). This research method can provide                     technical support for the fatigue life optimization design application of                     lightweight materials such as aluminum alloys.]]></description>
      <pubDate>Mon, 03 Aug 2026 15:15:58 GMT</pubDate>
      <guid>https://trid.trb.org/View/2742501</guid>
    </item>
    <item>
      <title>Effect of Ambient Humidity on Nitrous Oxide Emissions from Light Duty Vehicles</title>
      <link>https://trid.trb.org/View/2695912</link>
      <description><![CDATA[Ambient conditions around a vehicle affect the emission characteristics. The emission characteristics of Nitrous oxide (N₂O) under various ambient temperature conditions have been reported by other papers, but the effect of ambient humidity has not been focused on. In this report, the effect of ambient humidity on N₂O emissions from a gasoline vehicle was investigated using a chassis dynamometer. As a result, N₂O emissions decreased as ambient humidity increased. Furthermore, ambient humidity during preconditioning also affected N₂O emissions at the start of the homologation test.]]></description>
      <pubDate>Fri, 31 Jul 2026 09:23:51 GMT</pubDate>
      <guid>https://trid.trb.org/View/2695912</guid>
    </item>
    <item>
      <title>Novel Material Architecture for Enhanced High Cycle Fatigue Life in Turbofan Engine Fan Blades</title>
      <link>https://trid.trb.org/View/2712127</link>
      <description><![CDATA[High Cycle Fatigue (HCF) is a critical failure mode in turbofan blades, primarily driven by resonance phenomena when the blade’s natural frequency aligns with engine-induced excitations. Traditional approaches to mitigate HCF often involve geometric modifications or damping treatments, which can adversely affect aerodynamic performance or increase component weight. This study explores alternative methodologies to strategically alter the natural frequency of turbofan blades while maintaining aerodynamic efficiency and structural integrity. A novel material architecture is proposed, consisting of a dual-metallic configuration with a high-stiffness core and a lightweight, fatigue-resistant outer shell. This design enables precise tuning of the blade’s dynamic response by leveraging the contrasting mechanical properties of the core and outer materials. The dual-metallic structure shifts the natural frequency away from critical excitation zones, thereby reducing the risk of resonance-induced fatigue failure. Additionally, the hybrid configuration contributes to weight reduction compared to conventional monolithic blade designs, offering further performance benefits. Comprehensive Finite Element Analysis (FEA) is employed to evaluate modal characteristics and stress distribution of turbofan blades. Results indicate that the proposed architecture achieves a favorable balance between dynamic stability, structural robustness, and aerodynamic performance. The dual-metallic blade design not only improves HCF life but also provides a scalable framework for future turbofan blade optimization.]]></description>
      <pubDate>Wed, 29 Jul 2026 14:10:03 GMT</pubDate>
      <guid>https://trid.trb.org/View/2712127</guid>
    </item>
    <item>
      <title>Lightweight design of automotive parts based on the FPTO method</title>
      <link>https://trid.trb.org/View/2698262</link>
      <description><![CDATA[Topology optimisation is a method to maximise or minimise an objective function by optimising material distribution under design constraints. In the theoretical research of topology optimisation, most algorithms are developed on regular geometric models in software such as MATLAB. However, applying these findings directly to complex structures with irregular geometries in engineering is challenging. Optimisation of such structures relies on commercial software using density-based methods, hindering open algorithm research. The floating projection topology optimisation (FPTO) is a stable, efficient method producing good results. This study introduces the FPTO principles and investigates its integration on the MATLAB-ABAQUS platform, including conducting analysis in ABAQUS, performing optimisation solution and result visualisation in MATLAB, and facilitating data exchange. The boundaries of the topology structure are smoothed to better meet actual engineering requirements. This research explores the application of FPTO to automotive components, achieving lightweight designs for wheel hubs and control arms, offering an effective engineering solution.]]></description>
      <pubDate>Wed, 29 Jul 2026 09:16:18 GMT</pubDate>
      <guid>https://trid.trb.org/View/2698262</guid>
    </item>
    <item>
      <title>Presenting Spatial Data Mining Based on a Stage-Interpretable Multilayer Deep Learning Approach to Analyze the Factors Affecting the Crash Frequency of Light Vehicles in Rural Freeways</title>
      <link>https://trid.trb.org/View/2727485</link>
      <description><![CDATA[Some studies show that most light vehicle crashes occur on rural freeways. Crash frequency analysis presents significant challenges due to the complexity of large-scale datasets, hidden intervariable relationships, limited interpretability, and the influence of segmentation methods used. The present study aims to provide an innovative stage-interpretable multilayer perceptron (SI-MLP) method based on deep learning for quantitative and spatial analysis of the effect of geometric factors, weather conditions, and traffic parameters on the crash frequency by presenting a combined dynamic–static segmentation approach in rural freeways. The stage-interpretable method makes the interpretability of deep learning algorithm results possible by stepwise feature omission and assessing its impact on model accuracy. To this aim, significant variables were selected using a decision tree algorithm in conjunction with the Pearson correlation test. The Poisson regression model was utilized to compare the results with those of the proposed SI-MLP method due to the discrete nature of the data and the ability of such an algorithm to model the crash frequency. TabNet was also considered as a benchmark to assess the proposed SI-MLP, since it supports both crash frequency classification (enabling direct accuracy comparison with the MLP-based formulation) and regression-based crash frequency estimation as a numerical outcome. The results revealed that the proposed SI-MLP outperforms the Poisson regression model and the TabNet benchmark in identifying influential crash factors, owing to its ability to capture complex patterns and relationships and to extract high-level features from crash data enriched with geometric and weather information. In the three-class setting (low, medium, and high crash frequency levels), the SI-MLP achieved an overall accuracy of 0.81 and a Macro-F1 of 0.81. Based on the results, the vehicle type and color, license type, temperature, driver’s age, lighting conditions, and front collision with a fixed object were identified as variables affecting the crash frequency. In the next step, the effective variables identified by the proposed method were analyzed using thematic kernel density maps to model the clustering patterns and spatial autocorrelation of the crash frequency, with an emphasis on the most effective factors. Identifying key contributing factors within high-crash segments using the proposed approach allows for the formulation of targeted safety priorities and supports the deployment of proactive countermeasures in segments with the highest risk.]]></description>
      <pubDate>Mon, 27 Jul 2026 09:46:49 GMT</pubDate>
      <guid>https://trid.trb.org/View/2727485</guid>
    </item>
    <item>
      <title>Innovative metal wire reinforced honeycomb sandwich panels for lightweight, high-strength structural applications in transportation engineering</title>
      <link>https://trid.trb.org/View/2680744</link>
      <description><![CDATA[In the growing demand for lightweight and high-strength structural panels, this research focuses on the fabrication of Metal Wire Reinforced Foam Filled Honeycomb Sandwich Panels (MRFHS) using the Vacuum Assisted Resin Transfer Molding (VARTM) process. To tackle the issue of face sheet-to-core debonding commonly found in conventional foam-filled panels, two novel metal wire patterns of orthogonal (MRFHS1) and horizontal (MRFHS2) were inserted through the face sheets and polyurethane foam filled aluminum honeycomb core, followed by impregnation with polyester resin via the VARTM technique. The mechanical performance of the panels was evaluated using flatwise compression, edgewise compression, and flexural tests. These tests are critical for assessing compressive strength, flexural behavior, and damage resistance essential factors for understanding load-bearing capacity and structural reliability under various loading conditions. The results demonstrated that the MRFHS1 panels outperformed non-metal wire panels, showing 1.48 times higher flatwise compressive strength, 1.38 times greater edgewise strength, and 1.77 times improved flexural strength. The orthogonal wire insertion pattern in MRFHS1 panel effectively distributed applied stresses across the face sheet-core interface, enhancing interfacial bonding and minimizing structural damage than MRFHS2 and RFHS panel. Furthermore, statistical analysis using Machine Learning (ML) with Analysis of Variance (ANOVA) and Tukey Honestly Significant Difference (HSD) confirmed MRFHS1 as the best-performing panel. These findings highlight MRFHS1 panels as promising candidates for lightweight and durable structural applications across transportation and infrastructure industries.]]></description>
      <pubDate>Mon, 27 Jul 2026 09:46:48 GMT</pubDate>
      <guid>https://trid.trb.org/View/2680744</guid>
    </item>
    <item>
      <title>Fatigue bond behavior between high-strength lightweight aggregate concrete and high-strength steel bars</title>
      <link>https://trid.trb.org/View/2691376</link>
      <description><![CDATA[The bond behavior between high-strength lightweight aggregate concrete (HSLC) and high-strength steel bars under monotonic and fatigue loading is crucial for promoting the application of the two advanced materials in long-span bridges. In this study, three series of center pull-out tests were conducted to investigate the effects of concrete strength, anchorage length, stress level, and fatigue loading history on the bond performance between HSLC and HRB600 bars. Based on prior monotonic tests, the bond mechanism was analyzed, and a corresponding bond stress-slip model was developed. Fatigue test results revealed that the characteristic slips exhibited a three-stage development trend under repeated loading, which could be well-described by a power function. The bond fatigue life decreased with increasing stress levels but improved with higher concrete strength, and a simplified fatigue life prediction model was established and validated. Post-fatigue monotonic tests demonstrated that loading cycles led to increased bond stiffness and unrecoverable residual slip. The bond strength did not deteriorate when the fatigue relative slip was less than the peak slip under monotonic loading; otherwise, it decreased along the descending envelope of monotonic bond stress-slip curves. Finally, an empirical bond stress-slip model accounting for the fatigue loading history was proposed to accurately characterize the evolution of fatigue damage and post-fatigue behavior between HSLC and HRB600 bars. The research results could provide theoretical and practical guidance for predicting the bond stress-slip behavior after fatigue loading and evaluating the bond damage between HSLC and high-strength steel bars.]]></description>
      <pubDate>Wed, 22 Jul 2026 09:06:40 GMT</pubDate>
      <guid>https://trid.trb.org/View/2691376</guid>
    </item>
    <item>
      <title>Multi-Objective Optimization Research and Design of Seat Structure in Vehicle Collision</title>
      <link>https://trid.trb.org/View/2732206</link>
      <description><![CDATA[The vehicles often accompanied by a huge impact in the collision process, high-quality and high-strength car-seats can better protect the safety of passengers. However, in the call for vehicle energy saving and emission reduction, the lightweight design of car-seats is imminent. Therefore, it is necessary to achieve lightweight seat weight while ensuring vehicle safety. Based on the dynamic condition of vehicle collision, this paper takes the rear seat of a certain model as the research object, takes multiple responses of the seat skeleton system as the target, establishes a multi-objective optimization model of the seat skeleton, determines the optimization result with the greatest comprehensive satisfaction, verifies the optimization result of the seat skeleton. The correctness and feasibility of the design method are proved.]]></description>
      <pubDate>Tue, 21 Jul 2026 11:36:51 GMT</pubDate>
      <guid>https://trid.trb.org/View/2732206</guid>
    </item>
    <item>
      <title>Durability of Lightweight Concrete Bridge Decks in Utah</title>
      <link>https://trid.trb.org/View/2727688</link>
      <description><![CDATA[The objectives of this research were to document and compare properties of lightweight concrete and normal-weight concrete used for construction of bridge decks and approach slabs in northern Utah. The scope of work included field and laboratory testing to characterize concrete at three lightweight concrete bridge deck sites and the normal-weight concrete approach slabs at one of these sites, as well as laboratory testing to characterize concrete specimens obtained through previous research on lightweight and normal-weight concrete bridge decks. For field testing, a distress survey was performed at each test location, and then cover depth testing, Schmidt rebound hammer testing, resistivity testing, chloride concentration sampling, and coring were performed. For laboratory testing, regarding samples obtained during the current research, modulus of elasticity testing, compressive strength testing, splitting tensile strength testing, rapid chloride permeability and absorption testing, and chloride concentration testing were performed. Regarding samples obtained from previous research, coefficient of thermal expansion testing and freeze-thaw durability testing were performed. As a basis for discussion, ratios of values for lightweight concrete to values of normal-weight concrete were computed for selected properties, for which the normal-weight concrete approach slabs and the normal-weight concrete cores and cylinders were used as a baseline. The properties include resistivity, modulus of elasticity, compressive strength, splitting tensile strength, chloride permeability, absorption, coefficient of thermal expansion, and stiffness retained after freeze-thaw durability testing. Overall, the data suggest that, compared to normal-weight concrete, lightweight concrete absorbs more water, allows higher rates of chloride ion ingress, is more susceptible to degradation under freeze-thaw cycling, and has lower resistance to cracking. Several recommendations were developed to potentially improve the performance of lightweight concrete.]]></description>
      <pubDate>Tue, 21 Jul 2026 09:48:50 GMT</pubDate>
      <guid>https://trid.trb.org/View/2727688</guid>
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