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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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    <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>Springing and whipping</title>
      <link>https://trid.trb.org/View/2657972</link>
      <description><![CDATA[Elastic deformations of ship hulls caused by waves increase bending moments and hull accelerations compared to those of a rigid hull. The paper quantifies these effects for a large containership in three different natural head seaways by simulating rigid ship motions and vibrations. The simulation method uses a Rankine panel method to model the flow around the ship. Results show that, depending on the seaway, the fatigue damage rate of the real, elastic ship was up to twice that computed for the rigid ship, whereas the maximum total (still-water + wave) bending moment was up to 18 percent larger, and the standard deviation of the acceleration up to 10 percent larger. Moderate hull shape modifications, which were intended to reduce slam-induced vibrations, resulted in only small reductions of these effects. Because maximum vibrations are caused by seldom-occurring heavy slamming events, statistically reliable results require simulations of more than one hour duration for every selected seaway.]]></description>
      <pubDate>Wed, 24 Jun 2026 11:31:26 GMT</pubDate>
      <guid>https://trid.trb.org/View/2657972</guid>
    </item>
    <item>
      <title>New insights from full-scale measurements into structural response of high-speed catamarans to wave impacts</title>
      <link>https://trid.trb.org/View/2706921</link>
      <description><![CDATA[Increasing demand for efficient high-speed transportation has led to the evolution of high-speed catamarans for both commercial and military applications. In large wave conditions, all ships, including catamarans are prone to encounter waves imparting an impulsive slam load on the structure. Severe slam loads have been known to cause structural damage, while moderate impacts will cause whipping, which may have a negative effect on the fatigue life of catamarans. Extensive full-scale hull stress, motion, and wave measurements have been made during trials in the North Sea and North Atlantic region conducted by the US Navy on a 98 m Incat high-speed catamaran ferry designed by Revolution Design Pty Ltd and built by Incat Tasmania. The Empirical Mode Decomposition technique was used to remove both noise and the rigid body response from the acceleration signals to identify slam events. This was based on prior work by the authors and found to provide more reliable slam identification than traditional methods, but also provided a mechanism to isolate the structural response immediately following a slam, which was investigated in detail in the present study. A key outcome was the finding that slam events initiate from local impacts but produce a global structural response which can be traced over time between sensors, providing information about the impact location. These slam events were categorised based on port and starboard responses, and it was found that individual slams in head seas are rarely symmetric. This is a finding that will not be evident from model tests and simulations, and potentially calls into question the general validity of conducting model tests or simulations in pure head seas to study slams on multi-hull vessels.]]></description>
      <pubDate>Mon, 01 Jun 2026 09:14:40 GMT</pubDate>
      <guid>https://trid.trb.org/View/2706921</guid>
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    <item>
      <title>Mitigating load responses of high-speed catamarans via ride control systems: An experimental study in irregular waves, part2: Slamming kinematics and energy transfer</title>
      <link>https://trid.trb.org/View/2669916</link>
      <description><![CDATA[This study investigates the influence of a Ride Control System (RCS) with stern-mounted trim tabs and a bow-fitted T-Foil on slam kinematics and energy transfer during slamming, using a 2.5 m scale model of a 112 m Incat Tasmania high-speed catamaran in irregular waves. Towing tank tests were conducted at a forward speed of 2.89 m/s (37 knots at full-scale) in irregular head seas with significant wave heights of 60 mm and 90 mm, corresponding to 2.7 m and 4 m at full-scale, respectively. It was demonstrated that relative bow immersion is the kinematic parameter most strongly correlated with slam severity and is associated with a higher likelihood of severe slamming. In contrast, slam magnitude (quantified as peak integrated centre bow force derived from strain measurements) showed no strong correlation with either the relative bow velocity at the instant of slamming or the maximum pre-slam relative bow velocity. While these velocity factors showed weaker correlation with slam magnitude reduction compared to relative bow immersion, their importance increases when evaluating the effectiveness of control algorithms that similarly reduce relative bow immersion. The nonlinear pitch control algorithm was found to be the most effective in reducing relative bow immersion, reducing it by 17% and 21% in 60 mm and 90 mm wave heights, respectively, compared to the No RCS condition. Strain energy analysis revealed that this control algorithm reduced overall slam-induced strain energy of the model by 96% in 60 mm waves and 68% in 90 mm waves over a 54-second model test period compared to the No RCS mode. Furthermore, this algorithm mitigated the maximum peak strain energy in the centre bow by 70% in 60 mm waves and 47% in 90 mm waves, highlighting its potential to reduce slam-induced loads and improve the structural design of high-speed catamarans operating in challenging sea conditions.]]></description>
      <pubDate>Tue, 26 May 2026 11:56:22 GMT</pubDate>
      <guid>https://trid.trb.org/View/2669916</guid>
    </item>
    <item>
      <title>Wave slamming load inversion investigation of air cushion vehicle skirt airbags based on impulse-space superposition method</title>
      <link>https://trid.trb.org/View/2669912</link>
      <description><![CDATA[The flexible skirt airbag is the core component of air cushion vehicle, and the external load it bears under wave slamming directly affects the safety and stability of the structure. Due to the non-uniformity of wave slamming load in time and space, accurately inverting the dynamic load has become an important challenge in current research. This paper proposes a multi-region load inversion model based on impulse-space superposition method to address the inversion of spatial non-uniformly wave slamming load. The construction of the load-response relationship and the solution process of dynamic load inversion are explained. The response characteristics under unit load in a single sub-region are analyzed, and a preferred arrangement of monitoring points along the Y-direction is determined for subsequent inversion. The effects of wave slamming load duration, wave slamming load distribution and wave slamming load area on the inversion precision are discussed. As the load distribution becomes more complex and the areas are larger, the inversion error increases. Properly increasing the number of monitoring points can significantly improve inversion accuracy, especially in more complex asymmetric load scenarios. This inversion method is easy to implement and can provide valuable insights for subsequent research on load identification of air cushion vehicle flexible airbags in actual marine environments.]]></description>
      <pubDate>Tue, 26 May 2026 11:56:22 GMT</pubDate>
      <guid>https://trid.trb.org/View/2669912</guid>
    </item>
    <item>
      <title>Hydrodynamic and structural responses of air-cushion vehicle skirt exposed to underwater explosions</title>
      <link>https://trid.trb.org/View/2686771</link>
      <description><![CDATA[The skirts of air-cushion vehicles (ACVs) are subjected to highly nonlinear loads, which can compromise their stability and strength when exposed to underwater explosions. However, only a few studies have investigated the scenario of ACV skirts subjected to slamming loads or treated them as rigid bodies. Therefore, the aim of this study was to examine the hydrodynamic and structural responses of an ACV skirt under underwater explosion conditions. A numerical model was developed by coupling the control volume approach with the arbitrary Lagrangian–Eulerian method to examine these responses and was validated through a benchmark experiment. The results show that the occurrence of the plough-in phenomenon is governed by the detonation distance rather than charge weight. Given the complexity of the load, deformation, and maximum principal stress profiles, the corresponding numerical results should be used for evaluating the stability and strength of ACVs without simplification. The results of this study offer valuable guidelines for ACV design and navigation.]]></description>
      <pubDate>Thu, 14 May 2026 17:05:13 GMT</pubDate>
      <guid>https://trid.trb.org/View/2686771</guid>
    </item>
    <item>
      <title>Effect of Amplitude Profiles on the Structural Response of Modified Bottom Panels in High-Speed Craft due to Slamming Loads: A Finite Element Method Analysis</title>
      <link>https://trid.trb.org/View/2606213</link>
      <description><![CDATA[Slamming phenomena experienced by ships operating under extreme conditions can result in permanent hull deformation, potentially compromising structural integrity. This study investigates the permanent deformation of a 32-m high-speed craft due to slamming load using finite element analysis. A non-linear dynamic approach employing Abaqus Explicit was utilized to analyze structural deformation under maximum loads exceeding design limits, considering two pressure amplitude profiles: rectangular and triangular. The findings indicate that the rectangular amplitude produces higher deformation than the triangular profile, with maximum stress concentrated in the bottom chine area of the web frame. A design modification was introduced to mitigate permanent deformation by adding three different plates to reinforce the web frame in the bottom chine area. The result shows that flat bar C with a hexagonal shape was the most effective in mitigating dynamic loads and reducing deformation. These results underscore the critical role of structural modifications in enhancing ship design, significantly contributing to minimizing permanent deformation caused by slamming in high-speed craft. The study builds upon existing research on hull strength under dynamic loads and offers practical solutions for improving maritime safety and performance.]]></description>
      <pubDate>Mon, 27 Apr 2026 16:35:15 GMT</pubDate>
      <guid>https://trid.trb.org/View/2606213</guid>
    </item>
    <item>
      <title>Potential-flow multisection approach for the vertical water entry of elongated bodies</title>
      <link>https://trid.trb.org/View/2607063</link>
      <description><![CDATA[The present paper introduces a potential-flow multisection approach for analyzing the hydrodynamics of the vertical water impact of elongated bodies. In these cases the derivatives in the longitudinal direction are much smaller than those in the transverse plane and therefore the slender body approximation can be profitably exploited. The original 3D water entry problem is then approximated in a series of 2D problem, in an earth-fixed frame of reference, of the body cross section which are solved by using a fully non-linear potential-flow model. The multisection procedure here proposed, exploits a 2D fully non-linear potential-flow solver, based on a Hybrid BEM-FEM (HBF) approach, in which a Boundary Element Method (BEM) is coupled with a Finite Element Method (FEM) to compute the hydrodynamics of water impact problems. The model is developed and applied to the vertical water entry of aircraft fuselages for which experimental data are available. The evolution of the free surface at different sections and the associated pressure distribution are presented. Particular attention is paid at the integration of loads computed at the different sections in order to provide a prediction of the 3D hydrodynamic force acting on the entering fuselage. Comparisons with available experimental data are presented.]]></description>
      <pubDate>Mon, 27 Apr 2026 15:01:19 GMT</pubDate>
      <guid>https://trid.trb.org/View/2607063</guid>
    </item>
    <item>
      <title>Slam-induced loads on a three-dimensional stern model entering into water considering the bottom propeller shaft</title>
      <link>https://trid.trb.org/View/2607030</link>
      <description><![CDATA[The slamming load characteristics of stern structures under severe sea conditions are a research topic that deserves special attention. However, owing to the complex geometric characteristics of the stern, the current understanding of its slamming load characteristics is still insufficient. This study uses the computational fluid dynamics (CFD) method to conduct a numerical simulation study on the water impact problem of the stern structure of a container ship. Unlike previous studies, this calculation specifically considers the influence of the actual propeller shaft on the slamming process. The numerical calculation results were first compared with the existing experimental data for impact load verification, with errors within 10 %. Through numerical simulation, the details of the three-dimensional (3D) free surface flow that was difficult to observe in the experiment were successfully reproduced, and the flow separation and air bubble entrapment phenomena induced by the bottom propeller shaft were captured for the first time. The pressure distribution and slamming force characteristics of the stern surface for falling heights ranging from 250 mm to 900 mm were systematically analyzed, and the impact load‒time history curves of typical measurement points were discussed in detail. The findings reveal that fluid disturbances caused by the bottom propeller shaft weaken the correlation between the impact pressure and initial deadrise angle. Finally, the influences of parameters such as the impact velocity, model scale, shaft size, and model dimensions on the load characteristics were explored. These conclusions can help to improve our understanding of the slamming load characteristics of stern structures.]]></description>
      <pubDate>Mon, 27 Apr 2026 15:01:19 GMT</pubDate>
      <guid>https://trid.trb.org/View/2607030</guid>
    </item>
    <item>
      <title>Experimental investigation of wave forces on superstructures of coastal bridges with curved box–girders</title>
      <link>https://trid.trb.org/View/2695158</link>
      <description><![CDATA[Wave-induced loads on coastal bridge superstructures have been widely studied; however, the influence of curved box–girder geometry on wave impact remains insufficiently understood. This study presents a hydrodynamic experimental investigation of wave forces acting on a coastal bridge superstructure with a curved box–girder under regular waves with varying periods, amplitudes, and clearance conditions. Vertical and horizontal wave forces were measured using three-component load cells, and local pressures were recorded by an array of pressure sensors. The results show that the loading mechanism is strongly governed by the submergence condition. The most critical impacts occur under shallow-submerged conditions (−0.04 m ≤ C ≤ 0.00 m), where air–water interaction produces sharp pressure peaks and amplified wave forces. The slamming component gradually diminishes and approaches zero when the relative parameter (A−C)/hd exceeds approximately 0.4. Pressure measurements indicate that the maximum impact consistently occurs near the frontward underside of the girder. Under zero-clearance conditions, short-period waves generate broadband slamming responses with peak amplitudes about 65% larger than those of long-period waves, while the impact energy attenuates by over 90% along the girder. These findings provide experimental data and practical guidance for evaluating wave loads and determining safe clearance requirements for coastal bridges with curved box–girder superstructures.]]></description>
      <pubDate>Mon, 27 Apr 2026 15:01:12 GMT</pubDate>
      <guid>https://trid.trb.org/View/2695158</guid>
    </item>
    <item>
      <title>Dynamic in-plane slamming response of deck grillage with large-opening considering plastic accumulation</title>
      <link>https://trid.trb.org/View/2695151</link>
      <description><![CDATA[In severe marine environments, hull structures are subjected to combined quasi-static and dynamic loads, thus exhibiting significant dynamic responses under slamming loads. Moreover, cyclic wave actions can lead to accumulated plastic deformation and progressive stiffness degradation of the structure, which consequently threaten its structural integrity and safety. Based on the hull structural dynamic analysis theory, this study employs the nonlinear finite element method to investigate the dynamic collapse characteristics of a large-opening deck grillage under in-plane slamming loads. Parametric studies are performed focusing on loading velocity, loading duration, and static load. The dynamic slamming behavior of the structure associated with plastic accumulation is also discussed. The results demonstrate that plastic accumulation leads to a remarkable reduction in structural load-bearing capacity, and its adverse effect on dynamic capacity is more significant than that on residual static capacity. This study provides a useful reference for the safety assessment of hull structures under dynamic loading conditions.]]></description>
      <pubDate>Mon, 27 Apr 2026 15:01:12 GMT</pubDate>
      <guid>https://trid.trb.org/View/2695151</guid>
    </item>
    <item>
      <title>Coupling a time-domain code with a RANS solver for slamming analysis</title>
      <link>https://trid.trb.org/View/2632860</link>
      <description><![CDATA[A time domain hydroelastic code (TD) based on strip theory is two-way coupled with a Reynolds Averaged Navier−Stokes (RANS) solver to capture the bottom slamming effects on ships. The study is conducted on an Ultra Large Container Ship (ULCS). The methodology considers the hull’s flexibility and analyses longitudinal bending in head seas. Ship motions are calculated using a body non-linear time-domain method based on strip theory. The equations of motion are solved, and time integration is performed using the fourth-order Runge–Kutta method. When a slamming event is identified, the TD code activates a RANS solver to determine the bottom slamming force. The simulations are conducted under extreme sea conditions, and the hull experiences springing and whipping responses. The numerical results of vertical bending moments are compared with experimental data. The bottom and bow flare slamming are identified from the simulations.]]></description>
      <pubDate>Mon, 27 Apr 2026 14:59:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/2632860</guid>
    </item>
    <item>
      <title>Effectiveness and Improvement of Spectral Method for Fatigue Assessment Considering Elastic Vibration Response</title>
      <link>https://trid.trb.org/View/2675527</link>
      <description><![CDATA[In recent years, the increasing size of container ships has led to more frequent occurrences of elastic vibrations such as whipping and springing, which superimpose on wave responses and reduce fatigue life. Therefore, the importance of fatigue assessment considering elastic vibration is increasing. In this study, fatigue assessment using several spectral methods was conducted on stress measurement data from two large container ships, and the effectiveness of each method was examined. The spectral methods employed included the narrow-band method, the Jiao method for bimodal processes, and the DK method for wide-band processes. Their results were compared with those from the rainflow counting method. The results showed that the narrow-band method and the Jiao method tended to evaluate fatigue damage on the conservative side, while the DK method tended to yield less conservative (riskier) evaluations. The narrow-band method did not accurately reflect actual phenomena, as it deviates from actual rainflow counting. On the other hand, the DK method was found to be a good model that captures the real physical behavior. Therefore, a correction factor was introduced to the probability density function of the DK method to extend the distribution toward the higher stress range. By using the ratio of zeroth moment of the wave component and zeroth moment of the elastic vibration component, conditions likely to cause significant whipping were identified, and a formula for determining the correction factor based on this value was proposed. This approach enabled more accurate estimation of fatigue damage.]]></description>
      <pubDate>Mon, 27 Apr 2026 14:55:48 GMT</pubDate>
      <guid>https://trid.trb.org/View/2675527</guid>
    </item>
    <item>
      <title>Design loads for wave impacts — The Probabilistic Adaptive Screening (PAS) method for extreme non-linear hydrodynamic loads and responses of maritime structures</title>
      <link>https://trid.trb.org/View/2693287</link>
      <description><![CDATA[Wave impact loads on maritime structures can cause casualties, damage, pollution of the sea and operational delays. Consequently, their extreme values should be accounted for in the design of these structures. However, this is challenging, as wave impact events are both rare and highly complex, requiring both high-fidelity simulations and long analysis durations to reliably quantify the associated design loads. Moreover, existing extreme value prediction methods are neither specifically developed nor adequately validated for wave impact phenomena. We therefore introduce the new Probabilistic Adaptive Screening (PAS) method for predicting extreme non-linear loads on maritime structures. The method integrates copula-based statistical dependence modelling with multi-fidelity screening and adaptive sampling. This framework enables efficient extreme value prediction by statistically mapping low-fidelity indicator variables to high-fidelity impact loads. The method allows for efficient linear potential flow indicators to be used in the low-fidelity stage, even for strongly non-linear load cases. The statistical framework of the method is validated against four weakly and strongly non-linear test cases, including non-linear waves, ship vertical bending moments, green water impact loads, and slamming loads. It is concluded that PAS with optimal settings accurately estimates both the short-term distributions and extreme values in these test cases, with most probable maximum (MPM) values within 2–15% of the reference brute-force Monte-Carlo Simulation (MCS) results. In addition, PAS achieves this performance very efficiently, requiring in the order of 1–3% of the high-fidelity simulation time needed for conventional MCS. These results demonstrate that PAS can reliably reproduce the statistics of both weakly and strongly non-linear extreme load problems, while significantly reducing the associated computational cost compared to MCS.]]></description>
      <pubDate>Wed, 22 Apr 2026 14:59:35 GMT</pubDate>
      <guid>https://trid.trb.org/View/2693287</guid>
    </item>
    <item>
      <title>Study on nonlinear motion, wave run-up and slamming load characteristics of a semi-submersible platform sailing in head waves</title>
      <link>https://trid.trb.org/View/2653031</link>
      <description><![CDATA[The development of semi-submersible research platforms with high stability in harsh marine environments and safe navigation under varying sea conditions is a critical focus in marine science and technology. This study investigates the nonlinear characteristics of heave and pitch motions in a semi-submersible platform navigating in both regular and long-crested irregular waves through computational fluid dynamics (CFD) simulations and experiments. Wave run-up and slamming loads are analyzed experimentally, emphasizing the influence of speed and structural location on slamming intensity and spatial distribution. The results show that significant asymmetry between positive and negative motion amplitudes in both experimental and numerical analyses. Increased speed amplifies the asymmetry in motion amplitudes and enhances nonlinear behavior. These motion trends are closely related to the frequent wave impacts on the floating hull, especially in the bow region. A detailed discussion is presented on wave run-up and slamming effects under varying speed conditions. Wave impact loads on horizontal braces are more intense than those on the floating hull deck, although the impact frequency on the deck is higher. Additionally, The Froude number effect strengthens wave-platform interactions, influencing wave propagation and accumulation in the central region, leading to pronounced near-field interference.]]></description>
      <pubDate>Mon, 06 Apr 2026 08:50:03 GMT</pubDate>
      <guid>https://trid.trb.org/View/2653031</guid>
    </item>
    <item>
      <title>CFD-FEM simulation of hydroelasticity and slamming loads on an ultra-large container ship in 2D freak waves</title>
      <link>https://trid.trb.org/View/2684944</link>
      <description><![CDATA[To investigate the dynamic response characteristics of an ultra-large container ship under extreme sea conditions, this study conducts a systematic numerical simulation of the hydroelasticity and slamming loads of the ship in two-dimensional (2D) freak waves using a two-way fluid-structure interaction (FSI) method. Firstly, based on linear superposition theory, a phase modulation method for generating 2D freak waves at predetermined times and locations, which accounts for speed effects, was derived. The reliability of this method was verified through comparative simulations in STAR-CCM+. Secondly, a hull girder model was constructed from the actual ship's modal shapes. Numerical simulations in regular and 2D freak waves were performed to obtain results for the ship's heave, pitch, acceleration, sectional loads, and slamming pressure. The reliability of the numerical methodology was confirmed through time-step and grid convergence studies, as well as by comparison with model test results. Finally, the influence of wave height and ship speed on the ship's motion responses, sectional loads, and slamming pressure was systematically analyzed. This analysis revealed the generation mechanism of bending-torsion coupling excited by slamming in oblique wave conditions. This study provides an important basis for understanding the dynamic response patterns of ship structures under extreme sea conditions.]]></description>
      <pubDate>Thu, 02 Apr 2026 13:51:36 GMT</pubDate>
      <guid>https://trid.trb.org/View/2684944</guid>
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