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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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    <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>
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      <link>https://trid.trb.org/</link>
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    <item>
      <title>Development of Busbar with New Locking Mechanism for High Voltage EV Battery Applications</title>
      <link>https://trid.trb.org/View/2761785</link>
      <description><![CDATA[In the development of high-voltage (HV) batteries, ensuring secure connections between HV conductors and maintaining the safety and performance of the battery pack is paramount. Therefore, In the pursuit of enhancing efficiency and reliability in electrical connections, this paper explores the innovative alternate for a traditional screwing method with a friction locking mechanism for connecting busbars. The novel design reimagines the busbar as a Friction clamp (Female part) that securely holds the male part of the Busbar, significantly increasing the contact surface area up to 50%. This enhanced surface area not only improves electrical conductivity but also addresses heat generation issues associated with traditional screw-based connection. By eliminating the need for screws, the new design streamlines the assembly process, resulting in reduced cycle times and improved overall assembly line efficiency.This study presents the design methodology, performance analysis, and potential applications of the friction locking mechanism, demonstrating its advantages over conventional screwing methods in terms of thermal management, mechanical stability, and production efficiency. Post patent filing and concept approval, an iterative CAD-CAE loop was performed to refine and enhance the initial concept. Key takeaways from this process include critical material selection and potential design optimizations aimed at improving performance and manufacturing feasibility for series production implementation.The paper concludes with the results of prototype evaluations, rigorously tested against the current validation plan for series components to ensure compliance with required standards. ]]></description>
      <pubDate>Wed, 19 Aug 2026 13:48:42 GMT</pubDate>
      <guid>https://trid.trb.org/View/2761785</guid>
    </item>
    <item>
      <title>Design and Control of a Target Plate Fastener Assembly and Disassembly Actuator for Divertor Maintenance in Fusion Reactors</title>
      <link>https://trid.trb.org/View/2742555</link>
      <description><![CDATA[With the development of controlled nuclear fusion technology, the tokamak device, as the most promising magnetic confinement fusion reactor for advanced engineering applications, requires remote maintenance of its internal components, which has become a key factor affecting both operational efficiency and safety. As a critical component directly exposed to high-temperature plasma, the divertor target plate needs to be periodically replaced and carefully maintained to ensure stable and reliable reactor operation. However, this region is subject to extreme conditions, including high temperature, high vacuum, and intense radiation, making conventional manual maintenance infeasible. This necessitates the development of intelligent and automated teleoperation systems. To address the automated assembly and disassembly requirements of divertor target plates, this study designs an integrated target plate actuator comprising key functional units: a positioning module, a screwing module, a quick-change module, and a passive compliance structure. The actuator achieves rapid and precise alignment with target plate holes, accommodates bolts of different specifications, and exhibits excellent impact resistance. Furthermore, stiffness and mechanical analyses, supported by finite element simulations, verify the actuator’s safety and reliability under high loads and impact forces. To further enhance operational performance, a segmented disassembly and assembly control strategy based on reinforcement learning is proposed, enabling the actuator to adaptively handle torque variations and ensure precise and stable bolt operations. The results demonstrate that the proposed actuator and control strategy significantly improve the accuracy, stability, and efficiency of target plate operations under complex working conditions, providing a reliable solution for automated divertor maintenance in tokamak devices.]]></description>
      <pubDate>Mon, 03 Aug 2026 15:36:38 GMT</pubDate>
      <guid>https://trid.trb.org/View/2742555</guid>
    </item>
    <item>
      <title>A Comparative Study of Pin Connection Methods in Aircraft Structural Assemblies</title>
      <link>https://trid.trb.org/View/2732246</link>
      <description><![CDATA[In the aerospace industry, pins are crucial for fastening multiple connected structural parts, ensuring a flush connection that does not protrude from the assembly’s surface. These pins are installed through various methods to meet stringent mechanical and anti-loosening requirements, essential for aircraft structural integrity. Typical pin installation techniques include clearance fit with punch point installation, small interference fit with punch point installation, large interference fit with punch point installation, and interference fit without punch point installation. This study examines the connection reliability and manufacturability of different pin assembly processes, focusing on load testing under operational conditions. Results indicate that a small interference fit (0-0.01mm) combined with punch point installation provides high connection reliability and ease of manufacture, with punch point methods notably enhancing loadbearing capability and assembly integrity. In contrast, larger interference fits (0.01–0.04mm) require complex manufacturing steps, such as liquid nitrogen cooling for cold shrinkage, and the use of a shaft press for assembly, which increases difficulty and risks damaging both pins and surrounding structural parts. This research provides insights into optimizing pin assembly techniques to improve the durability and performance of aircraft structural assemblies.]]></description>
      <pubDate>Tue, 21 Jul 2026 11:36:51 GMT</pubDate>
      <guid>https://trid.trb.org/View/2732246</guid>
    </item>
    <item>
      <title>Mitigating Cracking in COP Optics through Annealing and Step-Torquing</title>
      <link>https://trid.trb.org/View/2712148</link>
      <description><![CDATA[Polymeric optical materials such as Cyclo Olefin Polymer (COP) are adopted in aerospace lighting systems due to their excellent optical clarity, dimensional stability, moldability and weight saving advantages over glass. However, their relatively low toughness and the presence of residual molding stress make them prone to crack initiation during mechanical fastening. During its installation, crack formation was consistently observed around self-tapping screw interfaces, raising concerns over reliability, maintainability, and compliance with durability requirements. A structured Design of Experiments (DOE) was performed to identify root causes and evaluate potential mitigation methods. The investigation revealed that residual stresses in the COP material, combined with localized stress concentrations during screw tightening, were the primary drivers of crack initiation. Two complementary process improvements were identified and validated as part of mitigation plan: (i) annealing of the optics prior to assembly to relieve internal stress, and (ii) using step-torquing method to fasten the screws, to gradually distribute applied loads and reduce localized stress peaks. Post-assembly observation over three days confirmed a significant reduction in crack initiation. The combined annealing and step-torquing approach demonstrated a substantial reduction in crack generation probability, providing a practical and repeatable process for enhancing the robustness of polymeric optic assemblies. This work contributes a generalizable methodology for mitigating assembly-induced failures in advanced polymer materials and supports broader adoption of lightweight, high-performance optics in aerospace applications.]]></description>
      <pubDate>Tue, 23 Jun 2026 13:32:53 GMT</pubDate>
      <guid>https://trid.trb.org/View/2712148</guid>
    </item>
    <item>
      <title>Ballast Aggregate Driven Nonlinear Environmental Stiffness in Heavy Haul Railway Fastenings: Novel Flexible Piezoelectric Sensor Monitoring</title>
      <link>https://trid.trb.org/View/2643911</link>
      <description><![CDATA[Ensuring the structural integrity of heavy-haul railway fastening systems is critical for operational safety and derailment prevention. Conventional rigid sensors suffer from bulkiness, poor embeddability, and limited dynamic performance, hindering their use in this demanding application. This study introduces a novel piezoelectric material engineered with a unibody design, offering inherent advantages of lightweight construction, flexibility, and conformability for integration into fastening components. Finite element analysis and D33 coefficient testing demonstrated that this smart material achieves superior strain distribution uniformity and signal stability compared to traditional clipped PVDF sensors. A specialized stepwise polarization-edge depolarization process was developed to enhance piezoelectric polarization uniformity, thereby improving measurement accuracy. The smart PVDF material was rigorously calibrated using a high-frequency impact system, and its fatigue resistance and stiffness-sensing capability were evaluated across varying environmental conditions. Integrated directly into rubber pads within a full-scale heavy-haul railway subgrade physical model, the smart PVDF material effectively quantified the environmental stiffness of the fastening system – capturing its dynamic interaction with the rock ballast aggregate – under diverse operational conditions. Results revealed a distinct nonlinear decrease in environmental stiffness with increasing speed and load, contrasting with universal stiffness trends and highlighting the critical role of rock ballast aggregate behavior. This smart PVDF material demonstrates exceptional durability and adaptability for monitoring nonlinear environmental stiffness responses in heavy-haul railway infrastructure, enabling advanced assessment of rock ballast aggregate-fastening system interactions and providing a promising foundation for intelligent track health monitoring and early-warning systems.]]></description>
      <pubDate>Wed, 25 Feb 2026 09:05:24 GMT</pubDate>
      <guid>https://trid.trb.org/View/2643911</guid>
    </item>
    <item>
      <title>AI-Driven Predictive Methodology for Bolt Integrity in Vehicle Durability Testing</title>
      <link>https://trid.trb.org/View/2663378</link>
      <description><![CDATA[The application of AI/ML techniques to predict truck endgate bolt loosening represents a major innovation for the automotive industry, aligning with the principles of Industry 4.0. Traditional physical testing methods are both expensive and time-consuming, often identifying issues late in the development process and necessitating costly design changes and prototype builds. By harnessing AI/ML, manufacturers can now analyze endgate slam and bolt preload data to accurately forecast potential bolt loosening issues. This predictive capability not only enhances quality and safety standards but also significantly reduces the costs associated with tooling and builds. The AI/ML tool described in this paper can simulate a variety of load conditions and predict bolt loosening with over 90% accuracy, considering factors such as changes in loads, bolt diameters, washer sizes, and unexpected masses added to the endgate. It provides valuable design insights, such as recommending optimal bolt diameters and the use of high-friction washers to ensure strong and reliable connections. By enabling continuous monitoring and real-time adjustments, this tool helps maintain the integrity of bolted joints under diverse operational conditions. This methodology reduces dependence on physical testing along with considerable cost avoidance and accelerates the vehicle development process. It offers a more efficient and cost-effective approach to vehicle development. Through the integration of these advanced technologies, the automotive industry can fully embrace the concepts of Industry 4.0, leading to smarter manufacturing processes and improved product reliability.]]></description>
      <pubDate>Mon, 02 Feb 2026 16:36:55 GMT</pubDate>
      <guid>https://trid.trb.org/View/2663378</guid>
    </item>
    <item>
      <title>Influence of Fastening Method of Wheeled Armored Vehicle on Flat Wagon for Forces Transmitted by Lashing Elements</title>
      <link>https://trid.trb.org/View/2604600</link>
      <description><![CDATA[During the transportation of cargo on the type Slmmps wagon platform, significant attention is paid to securing the transported load on a given wagon platform, primarily based on the imposed loading instructions. In the subject literature, there are no direct computational analyses on the forces acting on a specific type of cargo with a given mass, particularly under critical conditions. This article presents an analysis of the security of an armored vehicle in a platform wagon under critical conditions. Securing analysis was conducted for two fastening methods: the cross method (with a large strap angle relative to the direction of travel) and the straight method (with a small strap angle relative to the direction of travel). On the basis of these fastening methods, an assessment was made of the security of the transported cargo in the form of an armored vehicle. Armored vehicles are most commonly secured using the cross-fastening method with four securing straps. This study compares the force magnitudes concentrated on the securing straps in the cross-fastening and straight-fastening methods.]]></description>
      <pubDate>Mon, 22 Dec 2025 17:03:50 GMT</pubDate>
      <guid>https://trid.trb.org/View/2604600</guid>
    </item>
    <item>
      <title>Novel Methodology for Assessment of Bolted Joints Under Vibration Fatigue</title>
      <link>https://trid.trb.org/View/2624015</link>
      <description><![CDATA[The smart industrial revolution in any organization brings faster product delivery to the market, which can meet customer expectations and full life requirements without failure. Failure per machine (FPM) is a very critical metric for any organization considering warranty cost and customer perception. One such area which needs a detailed evaluation is bolted joints. Bolts play a pivotal role when integrating a subassembly with the main structure. Often, it is challenging to address bolt failure issues due to vibration induced in structures.Current bolt virtual evaluation methods help to evaluate bolts in simple loading conditions such as axial and bending loads. But it is quite complicated to evaluate the bolts which are prone to vibration loading. Traditional methods of using gravity loads miss out on dynamic characteristics, hence it must be simulated using modal dynamic analysis. With the current vADV (virtual accelerated design verification) method it is not possible to capture correct physics as modal analysis converts all frictional contacts to bonded contact resulting in change of load path.Different methodologies to evaluate bolts under vibration fatigue. Both the methods have shown good correlation with field data and have been utilized in ongoing product development programs to address ADV (Accelerated Design Verification) failures. Pros and cons of these methods are understood and documented in this study.]]></description>
      <pubDate>Thu, 13 Nov 2025 16:07:16 GMT</pubDate>
      <guid>https://trid.trb.org/View/2624015</guid>
    </item>
    <item>
      <title>Evaluating the Influence of Material Properties and Hardness on Tightening Torque</title>
      <link>https://trid.trb.org/View/2624009</link>
      <description><![CDATA[Earthmoving machines are equipped with a variety of ground-engaging tools that are joined by bolted connections to improve serviceability. These tools are made from heat-treated materials to enhance their wear resistance. Attachments on earthmoving machines, including buckets, blades, rippers, augers, and grapples, are specifically designed for tasks such as digging, grading, lifting, and breaking. These attachments feature ground-engaging tools (GET), such as cutting bits or teeth, to protect the shovel and other earthmoving implements from wear. Torquing hardened plates of bolted joint components is essential to ensure uniform load distribution and prevent premature failure. Therefore, selecting the proper torque is an important parameter. This study focuses on analyzing various parameters that impact the final torque on the hardened surface, which will help to understand the torque required for specific joints. Several other parameters considered in this study include hardware material, coefficient of friction, end bit and cutting-edge material, and their hardness. Understanding the influence of surface hardness on bolted joint torque is crucial for optimizing performance, reliability, and longevity of bolted connections in various engineering applications]]></description>
      <pubDate>Thu, 13 Nov 2025 16:07:16 GMT</pubDate>
      <guid>https://trid.trb.org/View/2624009</guid>
    </item>
    <item>
      <title>Strength Prediction of Self-Piercing Riveted Joints Using Practical
          Regression and Bayesian Neural Network</title>
      <link>https://trid.trb.org/View/2614422</link>
      <description><![CDATA[Self-piercing riveting (SPR) is a key joining method in multi/thin-material                     automotive structures, yet accurately predicting the mechanical strength of SPR                     joints remains challenging due to numerous influencing factors. Empirical                     engineering equations [1] provide a                     foundation for estimating lap-shear and cross-tension strength but require                     several geometric parameters that are often unavailable in the design phase.To address this limitation, we extract and leverage the core physical                     relationships embedded in these formulas. By reformulating the dependence of                     joint strength on the yield strength and total thickness of the sheet stack as                     practical regression models, we enable strength prediction using only commonly                     available material properties.Furthermore, a Bayesian convolutional neural network (BCNN) model is developed to                     incorporate additional material features, offering improved prediction accuracy                     and uncertainty quantification.]]></description>
      <pubDate>Mon, 27 Oct 2025 17:05:46 GMT</pubDate>
      <guid>https://trid.trb.org/View/2614422</guid>
    </item>
    <item>
      <title>Semi-Automatic Riveter G39 Replacement</title>
      <link>https://trid.trb.org/View/2552184</link>
      <description><![CDATA[This paper reports on a new design of semi-automatic riveting machine designed to be affordable. This work started in 2024. There are no customers yet. The machine is all electric. The machine installs interference bolts as well as squeeze rivets. Cost is a key criterion. The machine must feed a wide variety of fasteners. This machine is called Flexriveter.]]></description>
      <pubDate>Fri, 20 Jun 2025 17:03:01 GMT</pubDate>
      <guid>https://trid.trb.org/View/2552184</guid>
    </item>
    <item>
      <title>Optimization Methodology Development of FEA and Design Analysis on High Voltage Bolted Joints for Electric Vehicles</title>
      <link>https://trid.trb.org/View/2539255</link>
      <description><![CDATA[To promote the electric performance and safety of development for EV mobility, optimization methodology and design guide of high voltage bolted joint should be newly developed. This paper describes the development process of multi-physics (electrical, mechanical, thermal) FEA methodology, various experimental tests and establishment of optimization methodology of busbar bolted joint design in terms of bolt preload validation and joint temperature rise. The various key factors on high voltage joint tightening are quantitatively studied by utilizing this optimized methodology.]]></description>
      <pubDate>Tue, 15 Apr 2025 13:56:47 GMT</pubDate>
      <guid>https://trid.trb.org/View/2539255</guid>
    </item>
    <item>
      <title>Certification of Automatic Hydraulic-Squeeze Fastening Equipment</title>
      <link>https://trid.trb.org/View/1786062</link>
      <description><![CDATA[With the increasing shift toward automation with respect to fastener installation, the need has evolved for clearer definition of the process capability of new fastener installation automation systems. In light of Engineering design requirements, and to address the process capability issue, Boeing has developed and implemented D6-56617, a machine certification process for automated fastening of fuselage structure. This philosophy was a new approach in the following ways: (1) previously, engineering oversight of automated fastening systems was limited to wing structure applications; (2) the process requires that process capabilities and performance of the automated machinery itself be established by test; (3) the process requires that detailed Process Control Documents be developed and followed; and (4) the process links the statistical test data to the day to-day operating parameters of the machine.]]></description>
      <pubDate>Fri, 28 Feb 2025 16:43:20 GMT</pubDate>
      <guid>https://trid.trb.org/View/1786062</guid>
    </item>
    <item>
      <title>Flexibility in Fastener Feeding</title>
      <link>https://trid.trb.org/View/1786048</link>
      <description><![CDATA[This paper details the Electroimpact Cartridge Feed Auto Select (CFAS) System, the Electroimpact Cartridge Filling Station (CFS) and the implementation of these systems on today’s factory floors. Problems inherent in handling tens of thousands of fasteners per workpiece have traditionally been an Achilles Heel to many aerospace-manufacturing cells. The CFAS system moves the job of sorting through bulk fasteners to the stand alone offline CFS. With the bulk feeding process offline, problems such as contaminated fastener lots get taken care of before they ever get to a fastening machine. Modular briefcase sized coiled tube magazines store and distribute fasteners to automated riveting and bolting equipment via the CFAS rack. Cartridges captively hold 500 to 3,000 fasteners from 1/8” to 3/8” diameters and are length independent which allow a small number of cartridges to work with a large array of overall fasteners. Nearby storage of preloaded cartridges allow machine operators to quickly change out empty cartridges with full ones. Preloading of the fastener cartridge is done with a turnkey CFS. The standalone CFS uses vibratory bowls, grip-independent tooling, quick fastener change out features and feedback from counters and sensors to turn itself off upon each completed cartridge fill. Design factors and criteria will cover the driving issues behind cartridge filling, fastener storage, fastener delivery, orienting fasteners, reconfiguring the system, integration to current machines and the ability to be integrated with most automated riveting or bolting equipment.]]></description>
      <pubDate>Thu, 27 Feb 2025 10:44:46 GMT</pubDate>
      <guid>https://trid.trb.org/View/1786048</guid>
    </item>
    <item>
      <title>Threadless Sleeves on Threaded Pins</title>
      <link>https://trid.trb.org/View/1786038</link>
      <description><![CDATA[The standardization of fastening systems utilized in military and commercial aircraft vehicles supports the primary focus of IRAD 7-928 which is to develop and implement aircraft manufacturing technologies and processes best suited for affordability. Swaging lockbolt collars on threaded pins was initiated by St. Louis Phantom Works in August 1997 on the Electromagnetic Riveter (EMR) AFAS Test Bench. The goal of this concept is to develop a robust fastening system which combines the lower panstock cost elements of existing Hi-Lok and Lockbolt hardware.]]></description>
      <pubDate>Thu, 27 Feb 2025 10:44:46 GMT</pubDate>
      <guid>https://trid.trb.org/View/1786038</guid>
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