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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>Maneuvering coefficient estimation from frequency-dependent added mass and damping: A power-based approach</title>
      <link>https://trid.trb.org/View/2631557</link>
      <description><![CDATA[Accurate simulation and control of marine craft in waves requires models that account for fluid memory effects and wave-induced forces. Although seakeeping theory captures frequency-dependent added mass and damping by solving the Cummins equation, maneuvering models typically use constant hydrodynamic coefficients, often approximated at zero frequency, resulting in performance degradation in certain sea states. This paper presents a power-based averaging method to derive physically consistent equivalent added mass and damping matrices from frequency-domain seakeeping data. The method ensures that the total kinetic energy and the average power dissipation are preserved by weighting the hydrodynamic coefficients using a normalized wave spectrum. The method eliminates the need to select an ad hoc frequency, typically the zero frequency, and applies to both linear and nonlinear maneuvering models. The framework applies to six-degree-of-freedom (6-DOF) marine craft models at zero and nonzero forward speeds. Frequency-dependent wave excitation forces represented by response amplitude operators (RAOs) are added to the model by linear superposition. Validation using ShipX hydrodynamic data for the S175 container ship and WAMIT data for a standard tanker shows that the method avoids solving the Cummins equation while still producing accurate results for time-domain simulation and control design.]]></description>
      <pubDate>Mon, 27 Apr 2026 15:01:22 GMT</pubDate>
      <guid>https://trid.trb.org/View/2631557</guid>
    </item>
    <item>
      <title>Hydrofoil performance optimization based on the Kriging method</title>
      <link>https://trid.trb.org/View/2638247</link>
      <description><![CDATA[In order to design a new type of hydrofoil, which is much more useful in improving the seakeeping performance in the condition of the same projected area, an improved Kriging surrogate model-based optimization method coupled with an MSP-EI-MSE(Minimize Surrogate Prediction-Expected Improvement-Mean Square Error) parallel infill criterion is proposed in this study. The computing time needed is reduced approximately 22.46 % and the variance is reduced nearly 45.14 % compared with the existing methods. Subsequently, it is demonstrated by the application of the method to the hydrofoils of an unmanned catamaran that, the moment induced by the optimized hydrofoils in pitch motion is increased 19.59 % per unit area. Later, model test is adopted to validate results obtained in the simulation, Particle Image Velocimetry is used to obtain the details of the flow fields around the hydrofoils and analyze the effect caused by optimization.]]></description>
      <pubDate>Mon, 27 Apr 2026 15:01:20 GMT</pubDate>
      <guid>https://trid.trb.org/View/2638247</guid>
    </item>
    <item>
      <title>Dynamic characteristics and experimental investigation of weld-spot fixed rectangular plates</title>
      <link>https://trid.trb.org/View/2695407</link>
      <description><![CDATA[To meet the demand for vibration-resistant design of welded plate structures in the maritime and aerospace sectors, this study investigates the dynamic characteristics of thin-walled stainless steel rectangular plates fixed with weld spots. A dynamic model was established, treating the weld spots as local constraints. By combining the Rayleigh-Ritz method, von Karman large-deformation theory and classical laminate theory, a dynamic model was established in which weld spots serve as local constraints, with the spring stiffness adjusted using the stress influence range of a single weld spot obtained via DIC equipment. Parametric studies were conducted to explore the effects of plate geometry and weld spot parameters on natural frequencies. The results indicate that an increase in length/width reduces the frequency, while an increase in thickness raises it. Furthermore, frequency shifts and mode exchange phenomena were observed. Large-diameter weld spots can stabilize frequencies even in smaller quantities, whereas small-diameter weld spots require a greater number. This framework provides theoretical support for the lightweight design and safety performance of welded plate and shell structures.]]></description>
      <pubDate>Mon, 27 Apr 2026 15:01:13 GMT</pubDate>
      <guid>https://trid.trb.org/View/2695407</guid>
    </item>
    <item>
      <title>Comprehensive vibration and noise reduction characteristics of particle damping fastener systems using in prefabricated assembled ballastless track</title>
      <link>https://trid.trb.org/View/2624169</link>
      <description><![CDATA[The ballastless track structure is the main structure of urban rail transit, and the ballastless track has the advantages of high smoothness, high stability, and less maintenance. At present, urban rail transit requires high smoothness and convenient construction of track structure and also puts forward comprehensive requirements for vibration and noise reduction. This paper intends to combine particle damping fasteners with prefabricated track structure and analyze its comprehensive effect on inhibiting environmental vibration and wheel-rail noise while taking into account the characteristics of high smoothness and convenient construction and maintenance of track. The vibration and noise reduction are mainly achieved through the particle damping fastener system, while the prefabricated track primarily serves as a structural carrier for the particle damping fastener system, and mainly provides smooth performance, good constructability, and ease of maintenance. First, simulation models of typical metro vehicles, prefabricated assembled ballastless track with particle damping fasteners, and tunnel-earth environmental vibration characteristics are established. At the same time, a wheel-rail noise simulation model considering the above track characteristics is established. Based on the above two models, the vibration and noise reduction characteristics of preassembled ballastless track structure with particle damping fasteners are analyzed comprehensively. Through the research of track structure parameters, the comprehensive effect of vibration reduction of 9 dB and noise reduction of about 1.6 dB can be achieved. The research in this paper can provide reference for the comprehensive consideration of the smoothness, convenience, comfort, and environmental friendliness of the rail structure of urban rail transit.]]></description>
      <pubDate>Mon, 27 Apr 2026 14:59:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/2624169</guid>
    </item>
    <item>
      <title>Robust Model Predictive Control of Electrical Drives Considering Measurement Noises</title>
      <link>https://trid.trb.org/View/2659189</link>
      <description><![CDATA[In the realm of model predictive control (MPC) for electrical drives, the multiple vector MPC offers significant advantages with respect to its high current tracking accuracy and reduced current ripples, making it a promising alternative to conventional single-vector MPC. To compensate for the system disturbances due to model mismatches, extended-state observers (ESOs) are often integrated. However, the observer bandwidth relating to the disturbance rejection capability is usually compromised, since high bandwidth will inevitably amplify high-frequency measurement noises. To address this coupling issue between high-frequency noises in steady-state current and the disturbance rejection capability in transient scenarios, a novel triple-vector MPC is proposed in this article. Specifically, MPC incorporating an active damping method is proposed to improve the robustness against parameter mismatch and disturbances. Moreover, a dedicated adaptive current predictor is proposed to estimate current with one-step delay compensation, where an additional coefficient is designed to suppress measurement noises independently. To further enhance the flexibility of the current predictor, the adaptive mechanism based on the operation status is introduced to adjust the introduced coefficient. Comprehensive experiments have been conducted to demonstrate the superiority in both high robustness and noise suppression of the proposed controller.]]></description>
      <pubDate>Thu, 23 Apr 2026 13:54:25 GMT</pubDate>
      <guid>https://trid.trb.org/View/2659189</guid>
    </item>
    <item>
      <title>Approach for redefining the damping factor of railway bridges with ballast superstructure: model calibration and guidelines for practical application</title>
      <link>https://trid.trb.org/View/2663179</link>
      <description><![CDATA[To ensure the compatibility between rolling stock and infrastructure when dynamically assessing railway bridges under high-speed traffic, the damping properties considered in the calculation model significantly influence the predicted acceleration amplitude at resonance. However, due to the normative specifications of EN 1991-2, which are considered to be overly conservative, damping factors that are far below the actual damping have to be used when predicting vibrations of railway bridges, which means that accelerations at resonance tend to be overestimated to an uneconomical extent. Comparisons between damping factors prescribed by the standard and those identified based on in situ structure measurements always reveal a large discrepancy between reality and regulation. Given this background, this contribution presents a novel approach for defining the damping factor of railway bridges with ballasted tracks, where the damping factor for bridges is mathematically determined based on three different two-dimensional mechanical models. The basic principle of the approach for mathematically determining the damping factor is to separately define and superimpose the dissipative contributions of the supporting structure (including the substructure) and the superstructure. Using the results of a measurement campaign on 15 existing steel railway bridges in the Austrian rail network, the presented mechanical models are calibrated, and by analysing the energy dissipation in the ballasted track, guiding principles for practical application are defined. This guideline is intended to establish an alternative to the currently valid specifications of EN 1991-2, enabling the damping factor of railway bridges to be assessed in a realistic range by mathematical calculation and thus without the need for extensive in situ measurements on the individual structure. In this way, the existing potential of the infrastructure with regard to the damping properties of bridges can be utilised. This contribution focuses on steel bridges, but the mathematical approach for determining the damping factor applies equally to other bridge types (concrete, composite, or filler beam).]]></description>
      <pubDate>Wed, 22 Apr 2026 09:55:46 GMT</pubDate>
      <guid>https://trid.trb.org/View/2663179</guid>
    </item>
    <item>
      <title>An experimental study on the hydrodynamic performance of a stepped floating breakwater</title>
      <link>https://trid.trb.org/View/2660606</link>
      <description><![CDATA[This study experimentally investigates the hydrodynamic performance of a three-tier stepped floating breakwater, with a specific focus on optimizing its wave energy dissipation mechanisms. The stepped geometry functions as an effective dissipative structure. Through systematic physical model tests, the effects of relative draft, incident wave height, and mooring configurations on wave attenuation, motion response, and mooring force were examined. Results indicate that optimal wave energy dissipation performance, characterized by a maximum dissipation coefficient and a minimum transmission coefficient, is achieved at a relative draft (Dr/h) of 0.20 when subjected to shorter waves (B/L > 0.376). Conversely, when subjected to long-period waves, a deeper draft of Dr/h = 0.40 is required to maintain moderate attenuation (Ct < 0.7). Incident wave height was found to have a relatively minor influence, primarily affecting the pitch response amplitude operator (RAO) and normalized mooring forces. Furthermore, mooring configurations significantly impact the hydrodynamic performance of the stepped floating breakwater. While the taut mooring configuration suppresses motion response and achieves superior wave attenuation (Ct < 0.5) across the tested wave conditions, this comes at the cost of substantially higher mooring forces, presenting a critical trade-off for engineering design.]]></description>
      <pubDate>Tue, 21 Apr 2026 14:30:16 GMT</pubDate>
      <guid>https://trid.trb.org/View/2660606</guid>
    </item>
    <item>
      <title>Frequency-velocity-deflection-dependent damping properties of a hydro-pneumatic strut with gas-oil emulsion</title>
      <link>https://trid.trb.org/View/2691753</link>
      <description><![CDATA[A newly introduced gas-oil emulsion strut (GOES) is utilized in suspension systems studies, however, parametric analysis of the stiffness and damping characteristics of this strut has not been precisely addressed considering the effect of frequency, velocity, and deflection. Therefore, this study aims to analyze GOES’s properties based on parametric variations, namely, charge pressure, gas volume fraction, and initial gas-to-oil volume ratio. The experiment was conducted under three different charge pressures (0.68, 1.38, 1.79 MPa). The pressure/force-displacement and pressure/force-velocity properties of the strut were measured using harmonic excitations within the 0.1–6 Hz frequency range. The nonlinear pressure-dependent model was developed using the real gas law and was validated via the experimental data. The spring force and stiffness of the GOES were evaluated under ramp excitation with very low velocity (1 mm/s), and the effect of variations in terms of charge pressure, gas fraction volume, and gas-to-oil volume ratio on the stiffness properties were investigated. The predicted results revealed a negligible effect of gas volume fraction on GOES’s spring force and stiffness. However, stiffness properties were highly dependent on the charge pressure and gas-to-oil volume ratio. Experimental results demonstrated that the damping force of GOES is influenced by velocity, the strut’s instantaneous deflection, and the frequency of excitation. Furthermore, despite the same velocity and deflection resulting from different excitations, the absolute value of the damping force decreases with an increase in excitation frequency. In addition, parametric analyses focusing on damping force and coefficient were also performed. The results reveal that charge pressure has a minimal impact on damping properties. However, increasing the gas volume fraction from 0% to 15% and gas-to-oil volume ratio from 14% to 20% contribute to significant decreases in the maximum damping coefficient by 77% and 35%, respectively.]]></description>
      <pubDate>Mon, 20 Apr 2026 17:01:12 GMT</pubDate>
      <guid>https://trid.trb.org/View/2691753</guid>
    </item>
    <item>
      <title>Topology optimization design and fractional order sliding mode control of hub motor-driven vehicle dynamic inertial suspension</title>
      <link>https://trid.trb.org/View/2691751</link>
      <description><![CDATA[To address issues such as the negative effects of vertical vibrations caused by the wheel hub motor and the unbalanced radial forces resulting from motor static eccentricity, a topological optimization design method is proposed for the Hub Motor-Driven Vehicle (HMDV) dynamic inertial suspension based on Fractional Order Sliding Mode Control (FOSMC). Firstly, a static eccentricity model for a four-phase 8/6-pole switched reluctance motor is established, analyzing the unbalanced radial forces generated by motor excitation under varying static eccentricity. Subsequently, the impact of the dynamic inertial suspension’s topological structure on suspension performance is studied under the influence of the wheel hub motor’s self-weight and motor static eccentricity. Several superior dynamic inertial suspension structures that enhance suspension performance are identified. Next, optimization algorithms are employed to optimize the parameters of the dynamic inertial suspension, determining the topological structure that optimizes suspension performance. Then, a quarter-HMDV dynamic inertial suspension model based on the Acceleration-Driven-Damping (ADD) control strategy is developed, followed by an analysis of the mechanism for suppressing negative vertical vibrations in HMDV. Finally, the dynamic inertial suspension based on ADD is taken as the reference model, and the dynamic inertial suspension based on FOSMC is built, and the simulation and single-channel experiment are carried out. The simulation and test data show that the controlled dynamic inertial suspension has obvious inhibition effect on the deterioration of vehicle suspension performance caused by wheel hub motor.]]></description>
      <pubDate>Mon, 20 Apr 2026 17:01:12 GMT</pubDate>
      <guid>https://trid.trb.org/View/2691751</guid>
    </item>
    <item>
      <title>Physics-guided machine learning for ship biofouling assessment in support of maritime decarbonization</title>
      <link>https://trid.trb.org/View/2692623</link>
      <description><![CDATA[Ship biofouling significantly increases hull resistance and propeller loading, resulting in increased fuel usage and greenhouse gas emissions. This study presents a physics-guided machine learning approach for detecting performance degradation caused by biofouling. Physics-informed neural networks are first used to generate warm-up data that represent ideal, unfouled ship states under calm water conditions. A baseline model is built from this data and subsequently refined through an incremental learning scheme with new data collected in sliding temporal windows. The resulting incremental models are applied under reference conditions to quantify biofouling-induced performance changes, expressed as key performance indicators. Validation against conventional retraining approaches and the ISO 19030 standard shows that the proposed method more accurately captures both gradual degradation and rapid post-cleaning recovery. By delivering reliable and timely assessments of fouling impact, the framework supports optimized hull and propeller maintenance planning and contributes to improved energy efficiency and emission reduction.]]></description>
      <pubDate>Mon, 20 Apr 2026 09:25:29 GMT</pubDate>
      <guid>https://trid.trb.org/View/2692623</guid>
    </item>
    <item>
      <title>Spring with adjustable elastic constant: Application to vibration damping of an engine</title>
      <link>https://trid.trb.org/View/2686668</link>
      <description><![CDATA[Planar disk springs have been widely used in recent decades due to their compact geometry, long service life, and low cost. They require no maintenance or lubrication, making them highly efficient components for a variety of applications. In this work, a device was designed and characterized to regulate the elastic constant of a disk spring by varying the effective length of its flexure arms. Its mechanical behavior was simulated using the finite element method and experimentally validated using a tensile testing machine. The ability to vary the effective length of the device’s flexure arms enables adequate performance under varying operating conditions without the need to replace the spring. The proposed device covers a broad range of elastic constants (k) and has been successfully tested as a vibration damper in an engine operating under variable loads. Real-time adjustment of this constant allows for dynamic control of the ratio between the excitation frequency and the system’s natural frequency. Since the elastic constant k is a key variable in determining the resonant frequency, modifying it makes it possible to influence the system’s vibration modes. This capability facilitates the achievement of optimal damping conditions, which are essential for ensuring system stability and preventing structural damage. In addition, two different types of disks were used in the experimental setup, depending on the weight distribution at each support point of the system.]]></description>
      <pubDate>Mon, 20 Apr 2026 09:22:54 GMT</pubDate>
      <guid>https://trid.trb.org/View/2686668</guid>
    </item>
    <item>
      <title>Research on active disturbance rejection control of hydro-pneumatic suspension of engineering vehicle based on BP neural network</title>
      <link>https://trid.trb.org/View/2691758</link>
      <description><![CDATA[To enhance the ride comfort of the active hydro-pneumatic suspension and ensure system stability during an engineering vehicle’s operation, this study focuses on a dual-chamber hydro-pneumatic spring. It derives the relationship between the nonlinearity of the damping force and stiffness characteristics of the hydro-pneumatic spring and the vehicle body displacement. A control strategy is proposed to optimize the active disturbance rejection controller (ADRC) using a BP neural network. The neural network’s self-learning capability is employed for dynamic tuning of the ADRC parameters, thereby dampening body vibrations and achieving a stable condition. A two-degree-of-freedom dynamics model for a hydro-pneumatic suspension, along with a road input model, is constructed using MATLAB/Simulink. An optimized ADRC, leveraging a BP neural network, is integrated into the hydro-pneumatic suspension system. The vertical acceleration of the vehicle body and the dynamic load of the tire are adopted as evaluation indices. Through simulation analysis, the performance of the optimized algorithm is compared with that of an active suspension system controlled by both passive control and ADRC control. It is demonstrated that this optimization algorithm effectively reduces the vehicle body’s vertical acceleration and the tire’s dynamic load, thereby validating the efficacy of the control strategy.]]></description>
      <pubDate>Thu, 16 Apr 2026 16:55:28 GMT</pubDate>
      <guid>https://trid.trb.org/View/2691758</guid>
    </item>
    <item>
      <title>Efficient physics-based modeling and experimental validation of parallel-connected battery cells enabled by the transmission line model</title>
      <link>https://trid.trb.org/View/2684268</link>
      <description><![CDATA[Battery modules composed of parallel-connected cells are commonly used as building blocks of battery packs, but their behavior is complex due to cell dynamics, as well as cell-to-cell heterogeneities and interactions. Furthermore, their simulation by means of empirical equivalent circuit models poses limitations because of lack of generalization, whereas electrochemical models lead to a challenging calculation of the current distribution. In this article, an electrically consistent method for the calculation of the equivalent voltage and resistance of a cell is presented according to the physically motivated discrete transmission line model. This enables the efficient computation of output voltage and current distribution for parallel-connected cells while providing interpretable physical information about the operation at each level. The presented approach is validated experimentally against a dataset of a 4P module in which interconnection resistance, ambient temperature, and the presence of an aged cell are considered as input parameters, with accurate and consistent results for module voltage (≤20 mV RMS) and current distribution (≤4.4% RMS). Moreover, the proposed framework exhibits higher computational efficiency and comparable scalability in relation to established approaches, while providing improved consistency between module-level behavior and cell-level dynamics. Therefore, the proposed method based on the transmission line model and hierarchical simplification is a suitable alternative for the physically motivated simulation and analysis of battery modules.]]></description>
      <pubDate>Wed, 15 Apr 2026 10:30:18 GMT</pubDate>
      <guid>https://trid.trb.org/View/2684268</guid>
    </item>
    <item>
      <title>Numerical investigation of structural dimension effects on the extreme wave attenuation characteristics of floating breakwaters</title>
      <link>https://trid.trb.org/View/2656449</link>
      <description><![CDATA[This study systematically explores the impact of structural dimensions on the extreme wave dissipation performance of rectangular semi-submerged floating breakwaters based on a weakly compressible Smoothed Particle Hydrodynamics (SPH) model. Model accuracy is first verified against laboratory data for submerged horizontal plates test case. Wave height comparison between calculated results and experimental data shows a good agreement. Reflection, transmission, dissipation and overtopping coefficients under solitary waves are then analyzed. The results indicate that as the relative length increases, the reflection coefficient and dissipation coefficient increase monotonically with a gradually slowing growth rate, and eventually approaches 0.5 and 0.7, while the transmission coefficient exhibits a monotonic decrease toward 0.2. Short structures are dominated by wave transmission, whereas long structures are dominated by wave reflection and dissipation. It is recommended to take a relative length of 5–10 for a floating breakwater to achieve a balance between wave attenuation capacity and economic. Meanwhile, fitting formulas for the three coefficients, that apply to solitary waves, T = 0.6 m, and L/T = 0.1–50. were proposed. The determination coefficient R² for all fitted formulas exceeds 0.92. This study provides a support for the structural optimization of similar deep-water floating breakwaters and the design of extreme wave protection.]]></description>
      <pubDate>Mon, 13 Apr 2026 09:40:13 GMT</pubDate>
      <guid>https://trid.trb.org/View/2656449</guid>
    </item>
    <item>
      <title>An energy recovery device with variable damping for the Wave-Adaptive vehicle vibration control</title>
      <link>https://trid.trb.org/View/2687560</link>
      <description><![CDATA[This study presents the design of an electromagnetic variable damping (VD) device for wave-adaptive vessels, with the dual objectives of suppressing hull platform vibrations and demonstrating energy recovery (ER) capability. In contrast to conventional wave-adaptive vessel designs that predominantly employ springs and dampers, the proposed variable damping device is implemented as a linear motor equipped with resistance adjustment capability. By dynamically regulating the resistance of an external variable resistance module connected to the linear motor, the equivalent electromagnetic force generated by the VD device can be controlled in real time. Experimental tests validate the proposed model and accurately identify its key parameters. Subsequently, the variable damping device was integrated into a quarter-scale ship test platform to assess its feasibility. The wave-induced displacement of the ship raft, derived from hydrodynamic analysis, was applied as the excitation input. Experimental results demonstrate the device's outstanding performance: under a 60 kg hull load, the platform displacement is reduced by more than 60% compared to the excitation level, and the acceleration is decreased by 72.5%. The system achieves an electromagnetic power of 66.7 W, an output power of 35.2 W, and an electromagnetic efficiency of 0.547. This device not only broadens the application scope of variable dampers but also extends the research domain of semi-active control, showing significant potential in the field of vibration control.]]></description>
      <pubDate>Wed, 08 Apr 2026 13:55:55 GMT</pubDate>
      <guid>https://trid.trb.org/View/2687560</guid>
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