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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" />
    <description></description>
    <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>
    </image>
    <item>
      <title>Modeling and compensation method for hysteretic attribute of rubber bellows for air spring</title>
      <link>https://trid.trb.org/View/2680754</link>
      <description><![CDATA[The hysteretic attribute of rubber bellows and its model parameters characteristics varying with time at different pressures result in air springs characteristics alike, which affects the accuracy of the air suspension control systems. To solve this issue, a feedforward compensation control method for the rubber bellows based on its inverse model is proposed. Firstly, a modified Bouc-Wen pressure correlation model composed of a fractional order pressure correlation model and a general Bouc-Wen pressure correlation model of rubber bellows is put forward. Subsequently, a pressure correlation unified model of rubber bellows hysteretic attribute is constructed. The inverse models are derived from the modified Bouc-Wen pressure correlation model. Then, specific compensator structures are come up with. The results indicated that the mean absolute percentage error of hysteresis loops between the calculation and the test of the air spring is less than 1%. Moreover, the nonlinear error of hysteretic loops between the output force and input displacement of rubber bellows is reduced to 0.03% after compensation. Finally, a quarter-vehicle suspension model equipped with an air spring is established. After compensating for the hysteretic attribute of rubber bellows, the root mean square (RMS) of body acceleration is reduced by a maximum of 13.8%, the RMS of suspension dynamic travel is reduced by a maximum of 18.6%, and the RMS of tire dynamic load is reduced by a maximum of 13.5% under bump excitation, sinusoidal excitation, and B-class road random excitation, respectively. The results provide theoretical support for compensating the hysteretic attribute of rubber and cord multilayer composite viscoelastic elements and for accurately controlling air suspension systems.]]></description>
      <pubDate>Tue, 30 Jun 2026 15:52:43 GMT</pubDate>
      <guid>https://trid.trb.org/View/2680754</guid>
    </item>
    <item>
      <title>Nonlinear vibrations study of truck seat-cab suspension system</title>
      <link>https://trid.trb.org/View/2706054</link>
      <description><![CDATA[A four-degree-of-freedom nonlinear seat-cab suspension system was established by testing the mechanical properties of the air springs and fitting the test data with a cubic polynomial. On this basis, the whole-vehicle road sampling test technique and the bench load replication iteration technique was utilized to obtain the excitation signals of a Belgian road and general highway. Then, the vibration responses of the two road surfaces were investigated based on random vibration theory. The human vibration comfort evaluation was carried out using Chinese standards. Subsequently, the linear parameters of the suspension system were optimized and matched according to the design requirements of the suspension system using the multi-island genetic algorithm in Isight. Finally, the smoothness of the suspension system before and after optimization was simulated and verified. The results show that the new suspension system has better vibration isolation performance and greatly improves the comfort.]]></description>
      <pubDate>Tue, 23 Jun 2026 16:59:44 GMT</pubDate>
      <guid>https://trid.trb.org/View/2706054</guid>
    </item>
    <item>
      <title>Decoupling design and nonlinear modeling analysis of air spring with independent adjustment of height and stiffness</title>
      <link>https://trid.trb.org/View/2701148</link>
      <description><![CDATA[When the air spring is charged, it not only increases its own height, but also increases the stiffness of the air spring. The height and stiffness are coupled with each other, which limits the adaptability of the vehicle to various driving conditions. In order to solve this problem, a decoupling air spring whose height and stiffness can be adjusted independently is designed. Based on the existing decoupling scheme of height and stiffness and axiomatic design theory, the decoupling principle of air spring is analyzed, and a new decoupling scheme of two-chamber air spring is proposed. Considering the nonlinear problems of material, geometry, and contact in the modeling of air spring, an accurate finite element model is established to verify its performance. The results show that the stiffness and height of the decoupled air spring can be controlled according to the actual working conditions, which can improve the ride comfort and operation stability of the vehicle.]]></description>
      <pubDate>Wed, 20 May 2026 09:10:37 GMT</pubDate>
      <guid>https://trid.trb.org/View/2701148</guid>
    </item>
    <item>
      <title>An Improved Air Spring Model for Pantograph on the High-Speed Train</title>
      <link>https://trid.trb.org/View/2407477</link>
      <description><![CDATA[Air spring’s modelling is a relevant subject in the railway field, both for bogie and pantograph suspensions. Considering thermodynamic model has a great advantage for its accuracy and reliability, efforts and huge progress have been made before. However, there are still some parts where efforts could be made: although the air spring’s force and displacement’s relationship: F/x is mostly important, the thermodynamic model should theoretically demonstrate the relationship between different parameters, allowing to express the ratio between air spring’s pressure and displacement: Pa/x. By starting from some basic thermodynamic equations, this paper aims at modelling the relation Pa/x, with reference to an air spring of a high-speed train’s pantograph, with a pressure regulator mounted in the pneumatic system. Three different models have been proposed stage by stage. They are all validated by comparing simulation results with experiment results for frequency characteristics, the last one gives the best fit with the most cost. three models’ characteristics have all been explicated and differences have also been summarized.]]></description>
      <pubDate>Mon, 28 Jul 2025 08:55:35 GMT</pubDate>
      <guid>https://trid.trb.org/View/2407477</guid>
    </item>
    <item>
      <title>Modular simulation framework for the design of air-spring-dampers</title>
      <link>https://trid.trb.org/View/2543473</link>
      <description><![CDATA[Air-spring-dampers offer a novel alternative to traditional hydraulic damping within suspension systems. However, due to the intricate damping behavior and a multitude of configuration possibilities, the design process of air-spring-dampers proves to be challenging. This paper proposes a solution to address these challenges by introducing a simulation framework integrated with parameter optimization, enabling the simulation and design of any air-spring-damper. The simulation framework incorporates three fundamental modules: volume, mass exchange, and heat exchange. By abstracting the air-spring-damper as a graph and representing it via adjacency matrices, these modules will automatically be connected to construct a simulation model for any air-spring-damper configuration. Furthermore, leveraging the framework simplifies the design process through a parameter optimization. This method allows for a target damping curve to be set. The optimization algorithm then adjusts the air-spring-damper's design parameters until the target curve is achieved. A comparison of algorithms is conducted to determine the most suitable for this optimization problem. The pattern search and surrogate algorithms emerge as strong performers, effectively producing the target damping curve. To simplify the design process further, the common objective of enhancing driving safety and comfort is transformed into an optimization problem within the framework. This leads to the generation of a Pareto front, which presents design recommendations that balance safety and comfort optimally.]]></description>
      <pubDate>Mon, 28 Apr 2025 08:48:47 GMT</pubDate>
      <guid>https://trid.trb.org/View/2543473</guid>
    </item>
    <item>
      <title>Modelling of air springs for metro vehicles and studies on the effect of orifice damping</title>
      <link>https://trid.trb.org/View/2521800</link>
      <description><![CDATA[With the metro vehicle as the subject, a mathematical model of the main chamber, the auxiliary chamber and the orifice of the air spring were established based on the thermodynamic theory. The lateral nonlinear model is obtained based on the analytical geometry. Establish the four-point levelling valve and differential valve models through theoretical analysis. A complete three-dimensional air spring model is established. The correctness of the model is verified by comparing it with the actual data. The impact of orifice diameters and secondary vertical dampers on the dynamic performance of the metro vehicle is investigated. The results show that the secondary vertical damping configuration has a greater effect on vertical stability and acceleration but a minor impact on operational stability. Metro vehicles equipped only with air springs in the smaller diameter orifice do not need to be configured with a vertical damper, resulting in excellent dynamic performance and savings in production costs.]]></description>
      <pubDate>Thu, 17 Apr 2025 16:55:17 GMT</pubDate>
      <guid>https://trid.trb.org/View/2521800</guid>
    </item>
    <item>
      <title>A unified stiffness model of rolling lobe air spring with nonlinear structural parameters and air pressure dependence of rubber bellows</title>
      <link>https://trid.trb.org/View/2506342</link>
      <description><![CDATA[The structural parameters of the rolling lobe air spring and the mechanical characteristic of rubber bellows are the key factors affecting the stiffness and mechanical characteristic of the rolling lobe air spring. Aiming at the prediction difficulties of structural parameters of the rolling lobe air spring with the composite curved contour piston and the modeling complexity of the hysteretic mechanical characteristic of rubber bellows under variable pressure conditions, the geometrical method is applied to derive the structural parameters models of the rolling lobe air spring with the composite curved contour piston. A new pressure factor is introduced and the Coulomb frictional pressure perturbation model and the fractional derivative Kelvin-Voigt pressure perturbation model are reconstructed to accurately describe the hysteretic mechanical characteristic of rubber bellows under variable pressure conditions. A unified pressure equation is constructed to characterize the evolution of model parameters under variable pressure conditions. Furthermore, a hysteretic mechanical characteristic pressure perturbation model (abbreviated as HMCPP model) of rubber bellows under variable pressure conditions is put forward. Finally, a unified stiffness model of the rolling lobe air spring including prediction models of nonlinear structural parameters and a HMCPP model of rubber bellows is built. Taking a certain type of rolling lobe air spring as the test sample A, the structural parameters tests and static/dynamic characteristic tests of sample A are carried out based on the MTS852.05 test bench, which verified the accuracy of the unified stiffness model of the rolling lobe air spring. The research results provide theoretical support for the mechanical characteristic matching and air pressure precise control of the rolling lobe air spring under variable pressure conditions.]]></description>
      <pubDate>Tue, 11 Feb 2025 09:13:00 GMT</pubDate>
      <guid>https://trid.trb.org/View/2506342</guid>
    </item>
    <item>
      <title>Research on the influence of acoustic short circuit fault of air spring isolator on ship floating raft isolation system</title>
      <link>https://trid.trb.org/View/2437616</link>
      <description><![CDATA[Air spring isolator is the crucial component of ship floating raft isolation system. However, due to various factors such as manufacturing errors and installation conditions of air spring isolators, abnormal contacts cannot be avoided in the internal limiters of air spring isolator, resulting in the acoustic short circuit fault. This leads to a significant decrease in isolation effectiveness. To address this issue, experiments on the acoustic short circuit fault of air spring isolators are conducted, and the experimental results are analysed. Then the causes behind the phenomena and results of the acoustic short circuit experiments are further elucidated through finite element simulations and mathematical theory analysis. The research results indicate that the acoustic short circuit of air spring isolators affects the isolation effectiveness. The more severe the acoustic short circuit fault, the greater its impact on the isolation effectiveness, particularly in the low-frequency isolation component. This is because, during the acoustic short circuit of air spring isolators, the rubber part of the internal limiter comes into contact, causing an increase in the stiffness of the air spring support, thereby resulting in an increase in the modal frequency of the isolation device and consequently severely impacting the low-frequency isolation effectiveness.]]></description>
      <pubDate>Thu, 05 Dec 2024 09:38:10 GMT</pubDate>
      <guid>https://trid.trb.org/View/2437616</guid>
    </item>
    <item>
      <title>Numerical simulation and performance prediction of the ejection impact of air springs</title>
      <link>https://trid.trb.org/View/2410608</link>
      <description><![CDATA[To address the challenges of applying air springs in high-speed rail vehicle ejections, the ejection of a driver’s cabin structure is focused on in this study, and an ejection simulation model of an air spring is proposed using a series-parallel combination. The model’s accuracy is verified through virtual collision analysis of the driver’s cabin in a rail vehicle. The ejection velocity exhibits a relative error of only 9.1%. The test vehicle, driven by an air spring, achieves a maximum kinetic energy of 415 kJ, meeting the initial target value of no less than 408 kJ. Additionally, the analysis of the wheel-rail interaction reveals that the vertical lift and lateral displacement of the test vehicle are within acceptable limits, measuring 5.49 and 9.89 mm, respectively, without exceeding the wheel flange height and tread width. These results demonstrate that an air spring with a series-parallel combination can successfully propel the test vehicle to conduct the driver’s cabin collision tests without any derailment or overturning. Research on the ejection performance of air springs in this configuration offers a new driving and ejection method for applying air springs in rail vehicles, drones, and air-launched missiles, presenting promising prospects for future applications.]]></description>
      <pubDate>Sun, 18 Aug 2024 11:28:34 GMT</pubDate>
      <guid>https://trid.trb.org/View/2410608</guid>
    </item>
    <item>
      <title>Active vertical vibration suppression of high-speed railway vehicles by controlling internal pressure of the air spring using μ-synthesis control</title>
      <link>https://trid.trb.org/View/2384964</link>
      <description><![CDATA[In recent years, railway vehicles have become lighter since it corresponds not only to the improvement of the running speed but also to the reduction of running cost and environmental noise. On the other hand, this causes an increase in the vertical elastic vibration of the car body and the riding comfort has deteriorated. Therefore, various strategies to reduce vertical vibration have been studied. In this study, vertical vibration reduction, by controlling the internal pressure of the air spring using µ-synthesis control, is proposed. The merit of µ-synthesis control is that it can guarantee robust performance. A controller by µ-synthesis was designed for vibration reduction of a 1/6 scale railway model and compared nominal performance and robust performance with H∞ control theory. Moreover, a feasibility study of this strategy was investigated for full-scale railway vehicles through simulation.]]></description>
      <pubDate>Tue, 25 Jun 2024 10:34:17 GMT</pubDate>
      <guid>https://trid.trb.org/View/2384964</guid>
    </item>
    <item>
      <title>Research on Load Estimation for Commercial Trucks Based on Air Suspension State Parameters</title>
      <link>https://trid.trb.org/View/2389592</link>
      <description><![CDATA[For commercial trucks, accurate vehicle load information is crucial to preventing overloading and uneven load distribution, thereby improving transportation efficiency and reducing transportation costs. Existing research on vehicle load estimation primarily focuses on tires, axles, frames, and leaf springs, with limited studies on load estimation for vehicles equipped with air suspension. This paper presents the design of a vehicle onboard weighing system for civil commercial trucks based on the state parameters of air springs and proposes a matching method for vehicle load estimation. The system utilizes laser distance- and gas pressure sensors to collect the state parameters of the air springs. It estimates the vehicle load and displays the load information in real time on the onboard display. The vehicle load estimation method was explored through prototype testing and theoretical derivation. A fitting model was constructed using surface fitting techniques to establish the relationship between the effective contact area and the height variation and capsule pressure of the air spring. Subsequently, a load prediction model was built based on the force equilibrium equation of the air springs. Finally, the construction and accuracy of the load prediction model for a specific type of diaphragm air spring were verified using finite element analysis. The results demonstrated that the average relative error of the load prediction model could be controlled within 1%, meeting the high accuracy requirements of the vehicle weighing system.]]></description>
      <pubDate>Mon, 17 Jun 2024 09:38:54 GMT</pubDate>
      <guid>https://trid.trb.org/View/2389592</guid>
    </item>
    <item>
      <title>Modeling and Experimental Testing Analysis of Static and Dynamic Characteristics of Air Springs</title>
      <link>https://trid.trb.org/View/2367916</link>
      <description><![CDATA[In order to study the effects of different factors on the static and dynamic characteristics of air springs, three models were established to calculate the static and dynamic characteristics of air springs, including modeling at the design position, modeling only considering the straight state, and modeling considering the thickness of the bellows in the straight state. Static stiffness of air springs is calculated using three different models and are compared with experiments. In the straight state model considering the thickness of the bellow, the influence of aluminum tube and bellows thickness on the static stiffness are considered, and the modeling with the straight state solved the problem of the change in cord angle after the air spring was inflated and expanded. The established model is then used to calculate static and dynamic characteristics of air springs, such as static stiffness, hysteresis loop, and dynamic stiffness. The static stiffness, force versus displacement hysteresis loop, and dynamic stiffness of the air spring at design position are measured. The comparison of the calculation and experimental results showed that the result of modeling considering the thickness of the bellows in the straight state was more accurate, and the maximum relative error of static stiffness is less than 5%. The modeling and analysis methods in this article can predict the static and dynamic characteristics of air springs, providing guidance and reference for designing the static and dynamic characteristics.]]></description>
      <pubDate>Thu, 25 Apr 2024 16:20:05 GMT</pubDate>
      <guid>https://trid.trb.org/View/2367916</guid>
    </item>
    <item>
      <title>Analysis of the axial and transversal stiffness of an air spring suspension of a railway vehicle: mathematical modelling and experiments</title>
      <link>https://trid.trb.org/View/2320664</link>
      <description><![CDATA[The secondary suspension of railway vehicles is fundamental for their dynamic behaviour. This paper outlines a model-based procedure for predicting and evaluating the influence of different parameters in the static stiffness and vibration transmission of an air spring employed in the secondary suspension system of a railway vehicle. For that aim, a detailed and experimentally validated finite element model of the air spring is defined. It includes the behaviour of the reinforced elastomer, the inner pressure-deformation coupling and the thermodynamic interactions taking place inside the bellow. A Computer Aided Design of Experiments is employed to evaluate the influence of seven construction parameters of the bellow. Experimental tests and simulation results show that the air spring has natural frequencies below 100 Hz, in the frequency range where structure-borne vibration transmission occurs. The cord angle modifies the axial-transversal stiffness relation and a larger separation between adjacent layers and fibres delay the vibration transmissibility.]]></description>
      <pubDate>Thu, 29 Feb 2024 11:32:47 GMT</pubDate>
      <guid>https://trid.trb.org/View/2320664</guid>
    </item>
    <item>
      <title>Research on design and characteristic of a new type of air suspension system with magnetic negative quasi-zero stiffness</title>
      <link>https://trid.trb.org/View/2329960</link>
      <description><![CDATA[This paper designs a quasi-zero stiffness suspension with an air spring and a magnetic spring in parallel to improve the vehicle ride comfort. The proposed new suspension does not change the overall layout of the air suspension or affect the handling stability, reducing the system’s natural frequency by a sound vibration isolation effect for a low-frequency vibration and finally improving ride comfort. The feasibility of quasi-zero stiffness suspension is verified by mathematical modeling of air spring and magnetic spring, and reasonable structural parameters are set for the simulation experiment. The 1/4 vehicle model with two degrees of freedom is built in MATLAB / Simulink. Select body acceleration, suspension working space, and tire dynamic load as evaluation indexes to test the comfort performance of the proposed suspension. The result shows that the proposed new suspension has a noticeable effect on reducing the acceleration of the vehicle body and significantly improves the vehicle ride comfort.]]></description>
      <pubDate>Mon, 05 Feb 2024 09:35:52 GMT</pubDate>
      <guid>https://trid.trb.org/View/2329960</guid>
    </item>
    <item>
      <title>Thermodynamic models of the air spring on the high-speed pantograph</title>
      <link>https://trid.trb.org/View/2314067</link>
      <description><![CDATA[The modelling method of the air spring and its additional pneumatic system has been studied more frequently in recent years. As for the railway field, the study of the secondary suspension system of the bogie is the most popular, while little focus is on the air spring of the pantograph. In this paper, the modelling method of the air spring on the pantograph is investigated and developed. Four thermodynamic models are derived step by step, which can roughly be separated into two types. The first two models are established to express the relationship between the inner pressure and the vertical displacement of the air spring, and the effect of a regulator is illustrated and discussed. The latter two models that are developed from the first two models are set up to express the relationship between the vertical force and the vertical displacement of the air spring, where the effect of air spring material is illustrated and discussed. All four models are validated by comparing the simulation results with experimental results for frequency characteristics. Finally, the characteristics of the four proposed models are illustrated and discussed.]]></description>
      <pubDate>Mon, 29 Jan 2024 13:14:41 GMT</pubDate>
      <guid>https://trid.trb.org/View/2314067</guid>
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