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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>Mitigating roll response of high-speed catamarans by dual Demihull mounted T-Foils, Part 1: Design and validation in calm water open-loop tests</title>
      <link>https://trid.trb.org/View/2655862</link>
      <description><![CDATA[Efficient roll motion mitigation is essential for ensuring the structural integrity and passenger comfort of high-speed catamarans in oblique seas. Ride Control Systems (RCSs) used by Incat Tasmania wave-piercing catamarans (WPCs) typically consist of a single centrally mounted bow T-Foil and two stern-mounted trim tabs, and roll control relies solely on the independent action of the stern tabs, limiting their effectiveness for heave and pitch while not providing optimal ability to mitigate roll in beam and oblique seas. This study experimentally evaluates a new RCS that integrates dual demihull-mounted bow T-Foils with stern trim tabs. The system was implemented on a 2.5 m scale model of a 112 m Incat Tasmania WPC and tested in calm water at 2.89 m/s (equivalent to 37 knots full-scale) using open-loop step and frequency response experiments. Step response tests assessed heel responses under various demihull T-Foils and stern tab deflection patterns. The most effective heel excitation was achieved when the port and starboard demihull T-Foils and stern tab control surfaces operated in antiphase, increasing the heel range by about 43% compared to the centre bow mounted T-Foil RCS configuration. Frequency response tests demonstrated that the integration of dual T-Foils enhanced the RCS roll excitation capability by 45%. A lumped parameter approach was employed to derive and solve the roll dynamic equation of the model, which accurately predicted the heel responses observed in step response tests, with an average deviation of just 4.7%. It also predicted roll response and phase lag trends across a range of excitation frequencies, closely aligning with experimental trends. These findings highlight the significant improvement in the system’s roll control capability by incorporating demihull-mounted T-Foils into the RCS configuration, providing strong support for the new RCS design and laying the foundation for the development of a roll control algorithm for future closed-loop control experiments.]]></description>
      <pubDate>Mon, 02 Mar 2026 08:55:13 GMT</pubDate>
      <guid>https://trid.trb.org/View/2655862</guid>
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    <item>
      <title>Stability Analysis of Pantograph Under Sliding Condition Based on Frequency Response Function Measurement</title>
      <link>https://trid.trb.org/View/2635980</link>
      <description><![CDATA[Unstable pantograph vibrations can occur at low train speeds due to high friction. To reduce the cost of contact strip maintenance, this study proposes a stability analysis method that incorporates friction effects without requiring a complex analytical model. Instead of a complex analytical model, the method estimates the frequency response function (FRF) in the sliding state by measuring the FRF while a vehicle is stationary and applying an assumed friction coefficient. Modal characteristics are extracted from the estimated FRF, and stability is evaluated using damping ratios. The validity of this approach was confirmed by comparing its results with those from low-speed sliding tests.]]></description>
      <pubDate>Tue, 24 Feb 2026 15:39:55 GMT</pubDate>
      <guid>https://trid.trb.org/View/2635980</guid>
    </item>
    <item>
      <title>Prediction of Electromagnetic Vibration With Discrete Force–Response Matrix for Permanent Magnet Synchronous Motor</title>
      <link>https://trid.trb.org/View/2604080</link>
      <description><![CDATA[In view of the actual characteristics of electromagnetic (EM) force are ignored in existing vibration calculation models, this article proposes a hybrid calculation model based on a discrete force–response matrix for predicting EM vibration. Initially, the subdomain method is employed to calculate the air-gap force density (AGFD). Based on the mapping principle of air-gap force, an equivalent distributed force model is introduced, which accounts for the uneven distribution of radial and tangential EM forces on the tooth heads. Next, a frequency response function (FRF) model is developed to correspond with the distributed force. This model incorporates the circumferential variation of the FRF, and the differences in distribution patterns are analyzed. Subsequently, a vibration prediction model based on multipoint excitation and the multipoint response method is established. Finally, the accuracy of the proposed model is validated through vibration testing of the prototype, and the motor’s vibration modes are also confirmed.]]></description>
      <pubDate>Mon, 29 Dec 2025 09:37:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/2604080</guid>
    </item>
    <item>
      <title>In-cylinder Gas Temperature Measurement Using Fine Wire Thermocouple</title>
      <link>https://trid.trb.org/View/2582076</link>
      <description><![CDATA[A method for correcting the frequency response of fine wire thermocouples was applied for the first time to measure in-cylinder gas temperature. The study examined thermocouples subjected to FIB processing and those that were not. It was determined through frequency response theory that the necessary gain could be achieved and that a thermal inertia effect exists, indicating a required length for the processed section. Results from the actual engine implementation demonstrated the ability to accurately track temperature variations at 3000 rpm, confirming the effectiveness of this measurement technique.]]></description>
      <pubDate>Fri, 26 Sep 2025 13:39:58 GMT</pubDate>
      <guid>https://trid.trb.org/View/2582076</guid>
    </item>
    <item>
      <title>Response Characteristics and Regulation Feasibility of DC Charging Station Controlled by GFM/GFL Virtual Inertia for Grid Frequency Stability</title>
      <link>https://trid.trb.org/View/2559228</link>
      <description><![CDATA[To investigate the feasibility and differences between the grid-forming (GFM) and grid-following (GFL) control strategies for the frequency response (FR) in dc charging stations (CSs), this article first identifies the characteristics of the virtual inertia of GFM and GFL, and establishes an analytical model of the system FR considering FR in CSs. Second, the virtual inertia response control model of CSs is proposed under GFM and GFL controls, respectively. And their FR characteristics are analyzed. Finally, the FR characteristics of CS FR under variations of time delay, FR capacity, and virtual inertia are analyzed in the improved IEEE three-machine nine-node and ten-machine 39-node benchmarks. The results show that the FR of the GFM CS is less affected by time delay and can affect the grid frequency in the form of inertia when the amount of electric vehicles (EVs) required in the CS groups is about 300–400. Whereas the overcapacity of the GFL CS will cause the system frequency to oscillate. Therefore, the choice of virtual inertia control strategy adopted by the CS is closely related to the number of EVs in the station and its adjustable margin.]]></description>
      <pubDate>Fri, 08 Aug 2025 08:51:25 GMT</pubDate>
      <guid>https://trid.trb.org/View/2559228</guid>
    </item>
    <item>
      <title>Analytical study on nonlinear frequency response and vibration isolation of multistage clutch damper in automotive powertrain</title>
      <link>https://trid.trb.org/View/2488230</link>
      <description><![CDATA[This paper studies the nonlinear frequency response and vibration isolation performance of the multistage clutch damper at resonance. First, a 2-DOF drivetrain model is established considering the piecewise-linear stiffness, piecewise-linear damping and asymmetric transition angles of the multistage clutch damper. Then, the averaging method is employed to deduce the analytical solution of the nonlinear motion equation, and the stability of the periodic solution is studied using Routh-Hurwitz criterion. The nonlinear behaviors of the oscillator are discussed based on the theoretical results, and the numerical simulation is carried out to verify the credibility of the proposed method. Finally, the sensitivity analysis is conducted to investigate the influence of the system parameters on the amplitude-frequency response of the multistage clutch damper. The results indicate that the isolation performance of the multistage clutch damper is sensitive to the first and second stages of damping and the first-stage transition angles. By increasing the first and second stages of viscous damping by 50% and simultaneously reducing the first-stage angle range by 3° with 1° asymmetry, the isolation performance of the clutch damper is effectively improved, reducing the vibration amplitude at resonance by 28.8%.]]></description>
      <pubDate>Fri, 18 Jul 2025 09:05:44 GMT</pubDate>
      <guid>https://trid.trb.org/View/2488230</guid>
    </item>
    <item>
      <title>Real-time identification framework for instantaneous frequency of bridge cables considering multiple types of abnormal monitoring data</title>
      <link>https://trid.trb.org/View/2563175</link>
      <description><![CDATA[Real-time identification of bridge cable instantaneous frequencies is essential for accurate tension force estimation and reliable structural health monitoring. However, monitoring data often contain abnormal signals due to sensor failures, environmental interference, and network issues, which can significantly distort frequency identification results. This study presents a real-time framework that addresses the challenges posed by various types of abnormal monitoring data, including missing, drift, outlier, square, trend, and noise data. The proposed framework combines wavelet transform for precise time-frequency analysis with a k-nearest neighbor (KNN) model to detect and eliminate incorrect frequency identification results. Unlike existing approaches that rely on extensive data preprocessing or computationally intensive deep learning models, the proposed framework directly processes raw data, reducing both processing time and implementation cost. Validation on a large-scale cable-stayed bridge dataset shows that the framework achieves over 98 % accuracy in detecting incorrect frequency results. Furthermore, the corrected instantaneous frequency trends demonstrate a strong correlation with ambient temperature, highlighting the framework’s potential for practical deployment in continuous cable health monitoring applications.]]></description>
      <pubDate>Tue, 08 Jul 2025 09:56:46 GMT</pubDate>
      <guid>https://trid.trb.org/View/2563175</guid>
    </item>
    <item>
      <title>Dynamics analysis of nose landing gear shimmy performance considering aircraft structural flexibility</title>
      <link>https://trid.trb.org/View/2559329</link>
      <description><![CDATA[This study examines the sliding vibration characteristics of high-speed aircraft constructed with multi-layer composite materials and designed with a large cabin opening, which consequently leads to diminished overall structural integrity and lower natural vibration frequencies. To assess the influence of structural flexibility on the shimmy behavior of the nose landing gear during taxiing, a rigid-flexible coupling dynamic model was developed based on multi-body dynamics theory, integrating considerations of structural flexibility. The modal stiffness derived from this model was compared to that obtained from a finite element analysis, and simulations were performed to evaluate shimmy stability. The results reveal that fuselage motion enhances the damping coefficient for anti-shimmy while concurrently decreasing the oscillation frequency. When the structural frequency approaches the oscillation frequency, the stability of the system may be jeopardized. Therefore, it is crucial to prevent the alignment of the landing gear’s shimmy frequency with the structural frequency during the design process. Excessive flexibility in the fuselage can result in substantial lateral deformation, which disrupts the normal vibration pattern of the wheels’ angular motion and reduces the system’s capabilities for anti-shimmy and sliding control. Furthermore, when the fuselage demonstrates significant flexibility, the influence of the nose section on shimmy becomes pronounced, indicating that employing earpieces to simulate the body’s stiffness for shimmy analysis is not a suitable approach.]]></description>
      <pubDate>Thu, 26 Jun 2025 16:12:29 GMT</pubDate>
      <guid>https://trid.trb.org/View/2559329</guid>
    </item>
    <item>
      <title>A Method for Calculating Power Plant Order-Based Frequency Response Functions Using Finite Element Model</title>
      <link>https://trid.trb.org/View/2529552</link>
      <description><![CDATA[This study reports the development of a method for calculating an Order-based FRF using CAE analysis with a finite element model (FEM) for enhancing the sound quality of engine combustion noise. An FEM was created from a power plant model equivalent to a bench vibration test, and it was confirmed that an Order-based FRF similar to the experiment could be calculated. In order to simplify the analysis model, verification was carried out, so the main motion system model was omitted and a method of inputting the excitation force to the main bearing was considered. As a result, it was found that an Order-based FRF equivalent to the actual machine experiment could be calculated with only the power plant structure model. By using the CAE analysis method constructed in this study to calculate the Order-based FRF, it is possible to identify the frequency band and mode of concern for sound quality deterioration and to consider countermeasures at the pre-prototype stage.]]></description>
      <pubDate>Wed, 09 Apr 2025 09:52:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/2529552</guid>
    </item>
    <item>
      <title>Real-time synthesis of the dynamic responses of floating bodies to waves for maritime simulators</title>
      <link>https://trid.trb.org/View/2495468</link>
      <description><![CDATA[A new implementation of the Fourier approach to synthesize spectral waves in real-time was recently published by the authors, based on an efficient GPU implementation and on a very flexible definition of the wave inputs. This paper presents an extension of the method to deal with the time-domain synthesis of frequency-domain responses of floating bodies, which can be calculated offline with a linear seakeeping solver. The frequency-domain responses are mapped from frequency/direction space to wavenumber space in order to match the same wave components used by the synthesis of the ocean surface, and they are transformed into time-domain responses by means of Inverse Discrete Fourier Transforms. Given the large number of elementary wave components required for a realistic visualization of the ocean surface, the synthesis of dynamic responses becomes computationally expensive and was implemented on GPUs relying on parallel reduction algorithms to speed up the summations. The performance of the GPU implementation was investigated, showing how the present method can synthesize multiple dynamic responses in real-time even when dealing with many elementary wave components. The physical accuracy of the technique proposed in the paper was assessed by simulating a virtual wave measurement buoy: the frequency-domain responses of the buoy were calculated with a linear seakeeping solver and then synthesized according to the proposed method. Then, the timeseries of buoy motions were used to reconstruct directional wave spectra, which proved to be in very good agreement with the wave spectra provided as inputs for the simulations.]]></description>
      <pubDate>Fri, 31 Jan 2025 11:45:52 GMT</pubDate>
      <guid>https://trid.trb.org/View/2495468</guid>
    </item>
    <item>
      <title>Experimental and numerical approach to assess the dynamic performance of an inductive ignition system</title>
      <link>https://trid.trb.org/View/2393197</link>
      <description><![CDATA[This paper envisages studying the features of a conventional inductive ignition system along with its MOSFET and IGBT-based transistorized modifications. The influence of mechanical contact breaker dynamics and ignition coil characteristics on the current and voltage waveforms of the primary and secondary circuits of these studied ignition systems are mathematically and experimentally exposed. The investigation is considered necessary prior to attempting subsequent modeling and diagnostics procedures on the current-voltage performance characteristics of conventional and transistorized ignition systems. The work has demanded the development of an experimental setup based on a basic modifiable ignition system mockup and an instrumentation system to measure and analyze the voltage-current parameters of inductive ignition systems. The paper describes the design details of such instrumentation system, presents mechanical and electrical models for contact breaker and ignition circuits, then simulated to obtain base free-run response waveforms and electrical continuity behavior of the contact. A test of frequency response of the ignition coil provided additional input to the model. An experimental test of continuity of the contact, in agreement with its model, shed light on the actual excitation of the primary coil. The work comments on a sample of the registered current and voltage waveforms in primary and secondary coil windings of the ignition system at atmospheric conditions. Comparisons of waveforms and energy for mechanical contact, MOSFET and IGBT switches are made to establish them as a reference for future tests.]]></description>
      <pubDate>Fri, 09 Aug 2024 15:31:40 GMT</pubDate>
      <guid>https://trid.trb.org/View/2393197</guid>
    </item>
    <item>
      <title>The influence of vehicle dynamics on the time-dependent resonances of a bridge</title>
      <link>https://trid.trb.org/View/2265693</link>
      <description><![CDATA[In bridge structural health monitoring, the response of the bridge while the vehicle is on the bridge, is called a vehicle-bridge interaction (VBI) response. If the vehicle and the bridge are dynamically coupled, the VBI response depends on the bridge’s and the vehicle’s dynamic properties. Therefore, the damage detection techniques based on the bridge resonances become questionable due to the dynamic coupling between the bridge and the vehicle. This study investigates the influence of vehicle dynamics on the bridge’s time-dependent resonances. Vehicle-Induced Delta Frequency (VIDF) represents the changes in the bridge’s time-varying resonances resulting from the vehicle-bridge interaction, while Damage-Induced Delta Frequency (DIDF) accounts for the additional alterations caused by bridge damage. The dynamic interaction between vehicles and bridges (VBIs) is characterized by the frequency ratio between the vehicle (super-system) and the bridge (sub-system). The vehicle frequency is influenced by its dynamics, particularly the suspension systems. Two vehicle models, single suspension and dual suspension vehicles representing passenger trains and freight trains, respectively, are analyzed to assess the significance of vehicle dynamics on VIDF and DIDF. The results demonstrate that both vehicle models experience resonance, which magnifies the dynamic response to damage. However, not all types of vehicles possess the desired dynamic characteristics for effective bridge health monitoring. Trains with single suspension systems exhibit more pronounced changes in the bridge’s frequency response. This characteristic makes them more suitable for effective bridge health monitoring and damage detection.]]></description>
      <pubDate>Tue, 16 Jan 2024 09:03:27 GMT</pubDate>
      <guid>https://trid.trb.org/View/2265693</guid>
    </item>
    <item>
      <title>Evaluation of Frequency Response Characteristics on “g-g” Planes by Using Quasi-steady State Analysis</title>
      <link>https://trid.trb.org/View/1973313</link>
      <description><![CDATA[This study investigates a methodology to visualize the representative motion characteristics with consideration of running conditions, as well as the quantitative effects of the fundamental specifications for the vehicle dynamics. Frequency response is a method of evaluating the dynamic characteristics of a vehicle by examining the vehicle-motion response to steering input. Additionally, the proposed methodology considers running conditions which are represented by longitudinal and lateral accelerations, the response characteristics are visualized on “g-g” planes. Quasi-steady state cornering is assumed so as to calculate the characteristics with consideration of horizontal acceleration. Moreover, sensitivity is defined to evaluate the quantitative effect of a design parameter on a characteristic value which is the gain or phase of the frequency response, and the design parameters indicate the vehicle fundamental specifications in this study. It is also possible to visualize the sensitivities on “g-g” planes. The proposed methodology indicates relationships between the characteristics and the design parameters of a vehicle. This contributes to exploring a good design solution efficiently without many design iterations.]]></description>
      <pubDate>Thu, 04 Jan 2024 10:52:33 GMT</pubDate>
      <guid>https://trid.trb.org/View/1973313</guid>
    </item>
    <item>
      <title>Measurement of Dynamic Parameters of Automotive Exhaust Hangers</title>
      <link>https://trid.trb.org/View/1790642</link>
      <description><![CDATA[Different methodologies to test and analyze the dynamic stiffness (K) and damping (C) properties of several silicone and EPDM rubber automotive exhaust hangers were investigated in this research. One test method utilized a standard MTS hydraulic test machine with a single sine excitation at discrete frequencies and amplitude levels, while a second method utilized an electrodynamic shaker with broadband excitation. Analysis techniques for extracting the equivalent stiffness and damping were developed in the shaker tests using data from time domain, frequency domain, as well as force transmissibility. A comparison of all of the shaker testing methods for repeatability and accuracy was done with the goal of determining the appropriate method that generates the most consistent results over the range of testing. The shaker testing in the frequency domain using a frequency response function model produced good results and the set-up is relatively inexpensive. The hydraulic excitation method, however, is more suitable for large displacements and is ideal to study the variations of K and C with frequency, displacement, temperature and pre-load.]]></description>
      <pubDate>Fri, 22 Dec 2023 08:47:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/1790642</guid>
    </item>
    <item>
      <title>Simulation of Heavy Weight Deflectometer Test: Spectral Element Method vs Finite Element Method</title>
      <link>https://trid.trb.org/View/1973900</link>
      <description><![CDATA[The Heavy Weight Deflectometer (HWD) is a nondestructive testing device widely used for airfield pavement assessment. The HWD test consists in applying a wheel-representative load, generated by a falling mass, at the pavement surface. Deflections time histories are recorded by geophones located at several distances from the applied load. Inverse analysis procedures are needed to estimate layers mechanical properties, such as Young’s moduli for Linear Elastic (LE) materials or complex moduli for Linear Viscoelastic (LVE) materials. Most of inverse analysis processes consider (i) LE behaviour for pavement layers and (ii) static HWD loading. However, it has been shown that these hypotheses are leading to misestimate bituminous layers modulus and, in most cases, to poorly optimized maintenance. In order to better take into account bituminous layers behaviour, it is required to use LVE constitutive model and adapted numerical methods. This study presents a comparison between measured deflections and deflections computed using the Spectral Element Method (SEM) which was implemented during this work. The tested pavement was built within the test facility of the French Civil Aviation Technical Center (STAC). It is equipped with temperature probes at several depths within bituminous layers. The Spectral Element Method is a semi-analytical method in frequency domain. The pavement response is computed for unit load and for each frequency (from 1–200 Hz, every 1 Hz) at each geophone location, which leads to the Frequency Response Function (FRF). Then, frequency-domain deflections are obtained by weighting the FRF when calculating the Fast Fourier Transform (FFT) of the measured HWD load. This method is numerically efficient and shows good potential to solve axisymmetric multilayered problems. In particular, it allows to take into account frequency-dependent complex modulus analytical expressions. Spectral Element Method results have been validated with time-domain Finite Element Method data computed on a common pavement structure. SEM which is much faster than FEM shows great potential for further backcalculations application.]]></description>
      <pubDate>Sat, 21 Oct 2023 16:10:48 GMT</pubDate>
      <guid>https://trid.trb.org/View/1973900</guid>
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