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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>Investigation of the effects of chamber geometry and baffle cut-off ratios on the acoustic performance of reactive mufflers</title>
      <link>https://trid.trb.org/View/2719759</link>
      <description><![CDATA[The effects of chamber geometry and baffle cut-off ratios on the acoustic performance of reactive mufflers are numerically investigated in this paper. Mufflers with four different chamber geometries and three different baffle cut-off ratios are chosen for the study. All the three mufflers are modelled in such a manner that they have the same volume, length and inlet/outlet pipe dimensions. The models are analysed using COMSOL Multiphysics acoustic module. The transmission loss of each model for a target frequency band of 1,000-2,000 Hz is estimated and compared with that of others. The objective of the present work is to identify the best geometry and baffle cut-off ratio which gives maximum transmission loss for the desired band of frequency.]]></description>
      <pubDate>Wed, 23 Sep 2026 15:56:12 GMT</pubDate>
      <guid>https://trid.trb.org/View/2719759</guid>
    </item>
    <item>
      <title>Damping-enhanced tire-pavement noise mitigation of thermoplastic polyurethane/crumb rubber composite-modified asphalt pavements</title>
      <link>https://trid.trb.org/View/2737801</link>
      <description><![CDATA[Road traffic noise is a major environmental burden of urban transport, and tire-pavement interaction is a key source-control pathway. This study developed a damping-oriented noise-mitigation strategy for SMA-13 mixtures prepared with thermoplastic polyurethane/crumb rubber (TPU/CR) composite-modified binders. Laboratory damping and acoustic tests were combined with a coupled tire-pavement-air finite element model incorporating explicit tread patterns to link material damping, vibration attenuation, and transition in the dominant noise source. The results showed that TPU/CR modification enhanced the critical damping ratio, with the optimum response obtained at 6 wt% TPU + 10 wt% CR, representing an increase of up to 14.46% over the CR-modified mixture. Enhanced damping promoted viscoelastic energy dissipation and reduced vibration-induced sound pressure levels. Simulations revealed a speed-dependent transition: vibration noise dominated at 60–90 km/h, whereas air-pumping noise became the main contributor above 90 km/h. TPU/CR modification therefore provides a damping-oriented source-control strategy for reducing tire-pavement noise while maintaining pavement performance.]]></description>
      <pubDate>Mon, 03 Aug 2026 09:23:53 GMT</pubDate>
      <guid>https://trid.trb.org/View/2737801</guid>
    </item>
    <item>
      <title>The Degradation Processes of Noise Barriers and Their Impact on the Acoustic Characteristics of These Facilities</title>
      <link>https://trid.trb.org/View/2581490</link>
      <description><![CDATA[Due to the development of the economy and an increase in transportation volumes, the main source of acoustic pollution is the traffic flow. Noise barriers are the most effective solution for traffic noise protection for the areas that are located near roads and where it is required to maintain certain acoustic mode. From the experience of noise barriers use in other countries, it can be noted that over time these structures may lose their acoustic properties. The reason is that the noise barriers have low durability due to degradation of the materials from which they are produced. Degradation is most often manifested by changes in the structural integrity of the noise barrier, its physical and aesthetic state. This article gives a description of the research into the reduction of the acoustic efficiency of the noise barrier and presents the numerical values of this reduction in the noise and noise properties of the barrier in the presence of cracks. Regular monitoring of the noise barrier and minor repairs of several elements of the barrier will significantly increase its lifetime. This will improve the compliance with the acoustic mode of the area to be protected from noise and reduce the economic costs of the new noise barrier construction.]]></description>
      <pubDate>Mon, 27 Jul 2026 11:16:40 GMT</pubDate>
      <guid>https://trid.trb.org/View/2581490</guid>
    </item>
    <item>
      <title>Validation of an Adaptive Order Finite Element Model for Transmission Loss Simulation of Trimmed Automotive Structures</title>
      <link>https://trid.trb.org/View/2717289</link>
      <description><![CDATA[Vehicle electrification and increasing demands for driving comfort present significant challenges for designing effective noise control treatments (NCTs) in modern vehicles. Lightweight, low-emission designs often compromise acoustic efficiency. A popular and efficient way of compensating for this is through the use of multi-layer ‘trim’ material configurations to noise radiating surfaces to mitigate noise across a wider frequency range. Traditional 3D finite element models, while accurate and even needed to capture the full dynamic behaviour, become computationally prohibitive for complex automotive structures like firewalls, which feature intricate shapes, high curvature, and material compression. This computational burden limits design exploration and timely noise performance predictions.To overcome these limitations, this paper presents an innovative adaptive higher-order finite element method to evaluate the sound transmission loss (STL) of automotive, including the effect of poro-elastic and viscoelastic soundproofing materials. To show its capabilities, a digital twin was developed for a STL test setup for a production vehicle firewall with and without NCT. We present simulation results for different firewall configurations, comparing them against experimental data for the panel STL levels and relative improvements due to a NCT modification. The findings demonstrate the method's accuracy, efficiency, and applicability to real-world automotive engineering problems and also shed light on the trade-offs between model idealization and fidelity of the digital twin.]]></description>
      <pubDate>Tue, 30 Jun 2026 17:02:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/2717289</guid>
    </item>
    <item>
      <title>Vibration tests on different electric buses and routes in the city of Győr</title>
      <link>https://trid.trb.org/View/2685674</link>
      <description><![CDATA[In the vibration tests, three-axis accelerometers were installed on different electric buses (BYD, IKARUS). One sensor was placed on the chassis and another on the body. During the measurements, two directions of two sensors were recorded using an oscilloscope. On five routes, 10 different sections were recorded. The authors evaluated the root mean square (RMS) pulsation values of the vibrations in each case, as well as the maximum amplitude vibration of each section. The comparison tables show that there can be a difference of up to 40% in vibration intensity between the lowest and the highest loaded section. The comparative data show that the effect of chassis damping is to reduce the body vibration to 1/6 of the chassis load.]]></description>
      <pubDate>Tue, 19 May 2026 15:12:31 GMT</pubDate>
      <guid>https://trid.trb.org/View/2685674</guid>
    </item>
    <item>
      <title>Flutter Stability and Mechanisms of Long-Span Truss Girder Bridges in Mountainous Areas under Various Angles of Attack</title>
      <link>https://trid.trb.org/View/2688846</link>
      <description><![CDATA[The sensitivity of flutter performance to the angle of attack (AoA) poses a significant challenge for the aeroelastic safety of long-span truss bridges in complex mountainous wind environments. This paper investigates the flutter characteristics and underlying mechanisms of a truss girder through combined free vibration and forced vibration wind tunnel tests. Analysis of system responses identified three AoA-dependent flutter patterns: pure torsional flutter (+7°), torsion-dominated flutter with heaving participation (+3°), and classical coupled flutter (–7°). Self-excited forces and displacements were measured through forced vibration tests, and flutter derivatives were identified. The underlying flutter mechanisms were clarified by analyzing the work done by self-excited forces and the decomposition of aerodynamic damping components. It was found that the accumulation of positive work by the self-excited pitching moment triggers the instability. In contrast, the negative work done by the lift force at –7° enhances stability compared to positive AoAs. Analysis of aerodynamic damping components revealed that negative damping from the uncoupled term component dominates flutter onset. The uncoupled term provides negative damping during flutter, while the contribution of the coupled term to modal damping determines the flutter characteristics. When the positive damping from the coupled term is comparable in magnitude to the negative damping from the uncoupled term, the girder exhibits coupled flutter behavior. These findings provide a theoretical basis for understanding the complex aeroelastic behavior of truss girders under varying attack angles.]]></description>
      <pubDate>Tue, 19 May 2026 15:12:28 GMT</pubDate>
      <guid>https://trid.trb.org/View/2688846</guid>
    </item>
    <item>
      <title>Magneto-rheological isolation bearings vibration damping performance in an actual bridge based on the Bouc-Wen-Kelvin parallel model and second-order optimized LSTM: A case study of a 385m suspension bridge</title>
      <link>https://trid.trb.org/View/2692332</link>
      <description><![CDATA[To address the issues of inaccurate modeling of nonlinear mechanical responses in magnetorheological seismic isolation bearings under complex seismic motions and inefficient analysis of actual bridge damping performance, this study proposes a hybrid analysis framework (BWMLA) that integrates the Bouc-Wen-Kelvin parallel physical model with long short-term memory (LSTM) network-based temporal prediction. The core innovation of this work lies in constructing a Bouc-Wen-Kelvin parallel physical characterization model. By employing a phased collaborative optimization approach using genetic algorithms and Bayesian optimization for both physical parameters and LSTM network hyperparameters, it achieves a deep integration of physical mechanisms and data-driven insights. Field validation on a suspension bridge with a main span of 385 m demonstrated that the proposed framework achieved a root mean square error (RMSE) of 9.2 kN and a frequency-domain energy storage modulus error (Δk) of 5.1% for hysteretic force modeling, significantly outperforming the reference model. In the actual bridge testing, the RMSE between the predicted and measured values for structural deformation displacement and acceleration were 19.7 mm and 0.30 m/s2, respectively, with the coefficient of determination (R2) for the response spectrum reaching 0.91. This model provides a highly reliable tool for evaluating the performance of real-bridge vibration isolation systems and implementing adaptive control. Its high precision and efficiency enable direct application in guiding the optimized design of real-bridge isolation systems and the development of real-time seismic monitoring systems.]]></description>
      <pubDate>Tue, 19 May 2026 15:12:26 GMT</pubDate>
      <guid>https://trid.trb.org/View/2692332</guid>
    </item>
    <item>
      <title>Steering Motion Quality Oriented Return-to-Center Control Strategy for Vehicles</title>
      <link>https://trid.trb.org/View/2591155</link>
      <description><![CDATA[Most of existing steering system control strategies pay little attention to return time and speed. Additionally, most algorithms do not consider the impact of the applied torque of the driver on the steering wheel when determining the optimal return speed while the wheel is being held. This highlights an ongoing need to improve the return-to-center quality in vehicles. To address this challenge, this study proposes a steering motion quality control method based on a motion-closed loop. Here, we delineate the context wherein, by establishing a desired returnability, the return-to-center speed during release or holding phases is achieved via direct control through a motion closed-loop. This approach harmonizes the steering feel with the return-to-center performance, thereby enhancing the stability of the vehicle during straight-line driving. Subsequently, we validate the efficacy and robustness of the proposed steering motion quality-oriented vehicle return-to-center control strategy in managing returnability, as evidenced by low-speed and high-speed return-to-center simulation tests using a driving simulator.]]></description>
      <pubDate>Fri, 20 Mar 2026 14:10:50 GMT</pubDate>
      <guid>https://trid.trb.org/View/2591155</guid>
    </item>
    <item>
      <title>Analysis and Mitigation of Parasitic Noise in Hydraulic Engine Mounts: Addressing Cavitation and Membrane Hitting</title>
      <link>https://trid.trb.org/View/2663564</link>
      <description><![CDATA[Hydraulic engine mounts are widely used in automotive applications to reduce vibration and noise transmission from the engine to the vehicle body by providing high damping at low frequencies and low damping/stiffness at higher frequencies. This is achieved by allowing sufficient clearance between components inside the hydro mount, activating hydraulic damping only with sufficient amplitude inputs. However, this inherently leads to the generation of parasitic noises emanating from hydraulic engine mounts which significantly degrade the Noise, Vibration, and Harshness (NVH) performance of vehicles, presenting a considerable challenge in the automotive industry. This encompasses phenomena such as cavitation, arising from the formation and subsequent collapse of vapor bubbles within the working fluid due to localized pressure drops below the vapor pressure, and membrane hitting, resulting from the dynamic interaction between the fluid and the elastic membrane within the mount. Both noise sources are often difficult to trace back to the engine mount.This paper details a systematic approach for both detecting and mitigating these parasitic noise sources specifically in decoupled hydraulic mounts. This methodology is grounded in an investigative analysis conducted on a passenger car. The outcomes of this investigation offer practical strategies for pinpointing the fundamental causes of both cavitation and membrane hitting noise in hydraulic engine mounts and implementing effective solutions to improve overall vehicle NVH characteristics.]]></description>
      <pubDate>Fri, 20 Feb 2026 15:28:19 GMT</pubDate>
      <guid>https://trid.trb.org/View/2663564</guid>
    </item>
    <item>
      <title>Study on hydrodynamic noise characteristics of stiffened cylindrical shell with multilayer gradient acoustic coating</title>
      <link>https://trid.trb.org/View/2660734</link>
      <description><![CDATA[In this paper, the hydrodynamic noise characteristics of a finite stiffened cylindrical shell submerged in water are studied. The shell is covered with a multilayer gradient acoustic coating, and its outer surface is subjected to excitation of turbulent boundary layer (TBL) pressure fluctuations. The power spectral density (PSD) function of the modal pressure induced by TBL pressure fluctuations is computed using two analytical methods: the direct extension method and the comb function method. These methods extend the TBL wavenumber-frequency spectrum from planar to cylindrical surfaces through different approaches. Furthermore, the hydrodynamic noise predicted by these analytical methods is compared with results obtained via the finite element method and the statistical energy analysis (SEA) method. The comb function method is demonstrated to be more effective in accurately predicting the hydrodynamic noise of finite cylindrical shells. Additionally, variations in the acoustic impedance, density and sound velocity of the coating in the radial direction are explored to determine their impact on hydrodynamic noise control. The results show that, compared to an uncoated shell, a multilayer gradient acoustic coating with optimized parameters can significantly attenuate the hydrodynamic noise of a finite stiffened cylindrical shell.]]></description>
      <pubDate>Wed, 11 Feb 2026 15:10:45 GMT</pubDate>
      <guid>https://trid.trb.org/View/2660734</guid>
    </item>
    <item>
      <title>Novel evaluation methods for data-based determination of damping factors in the frequency and time domains with application on railway bridges</title>
      <link>https://trid.trb.org/View/2625376</link>
      <description><![CDATA[A realistic and economical dynamic assessment of railway bridges requires input parameters that correspond to reality. In this context, the applied damping properties of the structure have a decisive influence on the results in the prediction of resonance effects and further in the assessment of the compatibility between rolling stock and railway bridges. The standard prescribes damping factors depending on the type of structure and the span to be used in dynamic calculations. However, these factors can be regarded as very conservative values which do not represent reality. Thus, in situ measurements on the structure are often necessary to classify a bridge categorised as critical in prior dynamic calculations as non-critical. Regarding in situ tests, a measurement-based determination of the damping factor is inevitably accompanied by a scattering of the generated results due to the measurement method used and as a result of the individual scope of action of the test-evaluating person and this person’s interpretation of the measurement data. This paper presents novel evaluation methods and analysis tools for determining the damping factor based on measurements in the frequency and time domains, intending to reduce the scatter of the results and limit the scope of action of the person evaluating the test. The main aim is to provide simple and easy-to-use evaluation algorithms for practical applications without additional data transformations and to define clear principles of action for the data-based evaluation of realistic and high damping factors. Based on in situ tests on 15 existing railway bridges, the data-based procedure for determining the damping factor is explained, and the methods are compared in the time and frequency domains. It is shown that a clearly defined evaluation algorithm can significantly reduce the scattering of results. Furthermore, it is demonstrated that forced vibration excitation and evaluation in the frequency domain provide the best results in reliable, reproducible, and high damping factors.]]></description>
      <pubDate>Thu, 05 Feb 2026 16:39:49 GMT</pubDate>
      <guid>https://trid.trb.org/View/2625376</guid>
    </item>
    <item>
      <title>Research on New Type Secondary Inerter Suspension Damping Devices for Rail Vehicles Based on Low Frequency and High Frequency Track Excitation</title>
      <link>https://trid.trb.org/View/2526385</link>
      <description><![CDATA[Different types of secondary inerter suspension vibration damping devices are established set on the Matlab platform and compare and analyzes the dynamic indicators of vehicle operation, selecting the secondary inertial suspension damping device that significantly optimizes both the quality of vehicle operation and the suppression of low-frequency and high-frequency body sway. The research results indicate that for vehicle low-frequency swaying, all four types of new dual-system inertial damping suspension devices have an optimizing effect, with Condition S5 showing the most significant improvement. Compared to the traditional suspension damping device’s lateral acceleration of 1.62 m/s², it has been optimized by 57%, achieving 0.7 m/s². For vehicle high-frequency swaying, Condition S5 again showing the most notable improvement. Relative to the traditional suspension damping device’s lateral acceleration of 0.87 m/s², it has been optimized by 52%, reaching 0.41 m/s². After optimizing the parameters for various conditions, the results indicate that Condition S5, with an inertial coefficient of 5,000 kg, provides the best optimization effect on the stability of the vehicle’s operation.]]></description>
      <pubDate>Wed, 06 Aug 2025 08:54:45 GMT</pubDate>
      <guid>https://trid.trb.org/View/2526385</guid>
    </item>
    <item>
      <title>Development of Roll Stabilization for the Floating Dock at the Port of Long Beach Fireboat Station 15</title>
      <link>https://trid.trb.org/View/2559516</link>
      <description><![CDATA[The efficiency of a bilge keel to mitigate the roll motions of a floating dock at the Port of Long Beach (POLB) Fireboat Station 15 was investigated by means of Computational Fluid Dynamics (CFD) modeling. Free decay roll simulations of the existing and modified docks were performed, and resulting roll motions, natural periods, and damping ratios were compared. The modified dock included a vertical 3-ft-deep (0.91 m), 90-ft-long (27.4 m) bilge keel on one side. The simulations showed that the damping ratio of the existing dock was ζ = 0.048 and ζ = 0.121 for the modified dock. At 2.5 (= 0.121/0.048) times more damping than the existing dock, the bilge keel was considered an efficient means to reduce the dock roll motions, and the dock modification was implemented successfully.]]></description>
      <pubDate>Tue, 24 Jun 2025 15:24:08 GMT</pubDate>
      <guid>https://trid.trb.org/View/2559516</guid>
    </item>
    <item>
      <title>An investigation on the asphalt with enhanced damping properties: Development, performance evaluation and mechanisms</title>
      <link>https://trid.trb.org/View/2535133</link>
      <description><![CDATA[The present pavement noise-reduction approaches impair seriously the durability of pavement, therefore improving damping properties of pavement materials to attenuate noise is a developing trend. This study investigated an optimal component formulation designed to enhance damping properties of asphalt using recycled butyl rubber (RIIR) and styrene-butadiene-styrene (SBS) as modifiers. The pavement performance was examined to analyze the contributions of components in the asphalt through general properties, multiple stress creep and recovery (MSCR), bending beam rheometer (BBR) and segregation tests. Meanwhile, the microscopic morphology of asphalt was observed by Fluorescent Micrograph (FM) and Scanning Electron Microscope (SEM) in connection with the damping properties. The microscopic properties of asphalt were characterized using Gel Permeation Chromatograph (GPC), Fourier Transform Infrared Spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC). The results indicate that the combination of RIIR, SBS and sulfur contributes to enhance damping properties and pavement performance of asphalt. FM images present the interlocking continuous phases with interspersed elastic molecules and SEM images exhibit the folded mesh structures, which is the ideal morphology for the asphalt with enhanced damping properties. The tests on molecular structures, functional groups and thermal properties demonstrate that the particular sulfurized crosslinking structures restrict flow deformation and provide elasticity in asphalt, thereby manifesting in the enhanced damping viscous response and damping elastic response macroscopically. Consequently, these findings highlight the potential of damping compound-modified asphalt, promoting the advancements in noise-reduction pavement materials.]]></description>
      <pubDate>Wed, 14 May 2025 08:54:20 GMT</pubDate>
      <guid>https://trid.trb.org/View/2535133</guid>
    </item>
    <item>
      <title>Robust Single-Side-Current Damping Framework of High-Speed PMSM With Sine Wave Filter Based on Novel Duty-Cycle Updating Mechanism</title>
      <link>https://trid.trb.org/View/2511612</link>
      <description><![CDATA[In high-speed machine drives with sine wave filter, due to the synchronous transformation, the natural resonance in stationary coordinate will be converted into two resonances, which are located at fᵣₑₛ−fₑ and fᵣₑₛ+fₑ ( fᵣₑₛ is the natural resonant frequency, and fₑ is the motor frequency). Theoretical analysis and experimental results suggest that traditional active damping (AD) methods with high-pass filter cannot effectively address the dual resonance issue within a specific frequency range due to digital control delay. To address this issue, this article proposes a robust single-side-current (SSC) damping framework with novel duty-cycle updating mechanism to minimize control delay. In this way, a simplified expression between the system parameters and the damping coefficients is discussed for both inverter-current feedback (ICF) and motor-current feedback (MCF) systems. Experimental results illustrate that the proposal is stable for LCL resonance within the Nyquist frequency, while exhibiting strong robustness against parameter variation.]]></description>
      <pubDate>Fri, 04 Apr 2025 16:54:02 GMT</pubDate>
      <guid>https://trid.trb.org/View/2511612</guid>
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