Acoustic-induced vibrations pose a significant risk to launch vehicle hardware and payload reliability during critical phases such as lift-off and transonic phase. Reducing such vibrations is especially challenging when the hardware has already been fabricated, limiting the possibility of structural redesign. This study demonstrates a practical post-fabrication solution using a thin viscoelastic polymer coating applied externally to fully assembled hardware. Comprehensive evaluations were conducted using both acoustic testing and Experimental Modal Analysis (EMA) before and after coating application. During acoustic test, a substantial decrease in structure response from 150Hz to 2000Hz, with a reduction of approximately 50% in the grms values was observed for the coated structure demonstrating significant vibration mitigation over a wide frequency range. In contrast, EMA measurements using impact excitation revealed that the response transfer functions did not show a significant

Avirah, Nohin K, Panda, Ajay Kumar, Shaikh, Altafhusen

Mitigating Cracking in COP Optics through Annealing and Step-Torquing

2026-26-0764

To be published on 06/01/2026

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

S, Nikhil, Singh, Abhimanyu Kumar, Katageri, Praveen, SP, Pradeep, Chandra, Praveen

CFD based Prediction of Effective Area of a Ball Valve

2026-26-0724

To be published on 06/01/2026

The purpose of this document is to provide a template and guidance for the preparation of an SAE International technical paper. This template is comprised of the entire document “How to Write a Technical Paper” so that authors have all information where needed. You can use this template by removing all the content, text, and other information and then can use the “Styles” available in MS Word®. The main styles used are Heading 1, Heading 2, Heading 3, List Ordered Numeric (for numbered lists), List Unordered (for bullet lists), Normal (for the body of the text), Figure (for figure captions), Title (for Table titles), and Normal Table (for table body). To use the Styles feature, you can highlight the copy, select the drop-down beside Styles, and select which style you want. Alternatively, you can select the correct Style first and then begin typing. SAE International does not restrict the number of pages for a technical paper, although the recommended length is 9-12 pages in a 2-column

Turaga, Vijay Kumar, Aadi Gopalakrishna, Pradeep, Vasudevan, Dinesh Babu

Predictive Obsolescence Management

2026-26-0780

To be published on 06/01/2026

In the field of Aerospace, which has a long Life-Cycle process [20-30Years], Component Obsolescence has become a major problem as it prevents Maintenance & sustenance of a product with committed life-cycle period. Obsolescence Management plays a vital role by deriving strategic plans on proactive obsolescence where the system needs to be supported for several decades. This abstract analyzes the obsolescence challenges in the Aviation industry especially in Avionics System impacted by component obsolescence and present the possible proactive obsolescence management in terms of Engineering, Technology, and business/cost elements. The Obsolescence problem cannot be avoided but the impact of obsolescence and mitigate the risk can be minimized by planning and managing response. The obsolescence risk assessment for the Bill Of Materials (BOM) is a paramount activity to manage obsolescence proactively and cost-effectively. Digital Transformation of analyzing the component obsolescence status

Dharmananyala, Rohith, Munirathnam, Krishna, Marokeyfrancis, Joisyjose, Sadashivaiah, Nagesh, Kondamari, Harshitha

Hybrid Digital Twin for Aero-Engine Bearing Prognostics: A Physics-Informed Machine Learning Approach to RUL Prediction

2026-26-0718

To be published on 06/01/2026

Unscheduled maintenance due to the failure of critical components, such as aero-engine rolling element bearings, is a leading cause of costly Aircraft-on-Ground (AOG) events; consequently, current time-based maintenance practices are inefficient and prone to risk. This paper develops a resource-efficient Hybrid Digital Twin (HDT) model for an engine bearing, focusing on the dynamic prediction of spall growth due to Rolling Contact Fatigue (RCF), thereby enabling a condition-based maintenance paradigm. The HDT architecture integrates two core models: (1) a physics-informed model that uses established life and fatigue theory to define initial degradation thresholds, and (2) a data-driven Recurrent Neural Network (RNN), specifically a Long Short-Term Memory (LSTM) network, for dynamic degradation rate modeling. The methodology utilizes a Monte Carlo simulation coupled with RCF progression equations to generate a large, high-fidelity synthetic run-to-failure dataset under varying

Mohamed, Abbas

Finite Element Approach for Fatigue Life Prediction of Threaded Bolts with Experimental Validation

2026-26-0745

To be published on 06/01/2026

Predicting the fatigue life of threaded bolts is crucial in aerospace and mechanical assemblies where cyclic loading can cause early joint failure. Existing studies, like [1], have created S-N curves for high-strength bolts under different pretension and temperature conditions through experimentation. However, there are few numerical methods that can replicate these results, especially for bolts without pretension. This study develops and validates a finite element analysis (FEA) methodology to predict the fatigue performance of pretensioned threaded bolts under axial loading, using the experimentally derived Series-2 S-N data for M20 high-strength bolts with pretension. The approach employs a detailed 3D solid model with explicit thread geometry and a two-step transient structural analysis. This first simulates the bolt tightening process to establish a realistic preload, followed by the application of a service tensile load. Local stress distributions are analyzed to extract peak

K R, Lesanth, S, Suhail Ahmed, C, Arunvetrivel, P, Krishnakumar, P S, Premkumar, Vasantharaj, C

Design Optimization of Aircraft Light Optics: Eliminating Fasteners by Flexure-Based Clamp to Mitigate the Crack Formation and Validation through HALT

2026-26-0750

To be published on 06/01/2026

Aircraft lighting systems play a vital role in ensuring operational safety, visibility, and regulatory compliance. Exterior lighting systems are essential for aircraft identification, navigation, collision avoidance, and ground operations under varying environmental conditions. These systems typically include navigation lights, anti-collision lights, landing and taxi lights. An aircraft lighting system comprises light sources, optical elements, electronic control units, power interfaces, wiring harnesses, and mechanical mounting structures. Among these components, optics are critical as they control light distribution, intensity, color accuracy, and efficiency while withstanding harsh aerospace environments such as vibration, thermal cycling, and aerodynamic loads. Aircraft exterior lights are subjected to severe thermo-mechanical stresses due to aerodynamic loading, vibration, and thermal cycling. The use of high-performance optical polymers such as Cyclo Olefin Polymers (COP

Vialta, Frederico, S, Nikhil, Katageri, Praveen, SP, Pradeep, Singh, Abhimanyu Kumar

Effect of Fluid Flow/Time Duration on Static Voltage Generation for Aerospace Hose Assembly

2026-26-0757

To be published on 06/01/2026

Static electricity is an electrical imbalance on the surface of a material which can interact with other components having same or different materials. Fluid flow within the hose assembly generates static voltage due to friction caused by fluid flow in pipes, that needs to be appropriately quantified and dissipated. Accumulation of such static charge may lead to sudden discharge leading to spark generation. Spark generation around fuel flow might lead to system failure and failure in aircraft engines. Test experiments were conducted to analyze static voltage generated in hose assembly due to fuel flow with the objective that voltage achieved is within the acceptable range to avoid ESD (Electrostatic Discharge) failure. Procedure includes flow rate monitoring and voltage measurement using fuel as test fluid. The testing revealed that the curvature of the hose affects the readings, highlighting the importance of consistent meter alignment. Using a grounding strap is essential to prevent

Waghmare, Shashank

Evaluating Volume and Hardness change in Fluorocarbon and Ethylene Propylene Rubber Elastomers: Effects of Fluid Aging

2026-26-0758

To be published on 06/01/2026

Abstract: This research paper investigates the performance of FKM (Fluorocarbon) seal material when exposed to a 50:50 ethylene glycol-water mixture. The study aims to determine the volume change percentage and Hardness change of FKM elastomers under standardized testing conditions. The experimental approach follows ASTM D471 and ASTM 2240 guidelines, focusing on weight and hardness measurements of the test samples to establish a success criterion. The results provide critical insights into the chemical compatibility and durability of FKM elastomers in Aerospace and industrial applications where ethylene glycol-water mixtures are commonly used. The findings contribute to enhanced material selection and design considerations for sealing applications subjected to glycol-based fluids. Samples of FKM material were immersed in the fluid at controlled temperatures and durations, simulating real-world operational conditions. The primary metric of interest, volume change percentage and

Yarolkar, Makrand, Patil, Sandip, Singh, Tanul

Enabling Circularity in the Aerospace Maintenance Ecosystem through Generative-AI Driven Back-to-Birth Traceability of Life-Limited Engine Parts

2026-26-0719

To be published on 06/01/2026

Circular-economy principles are increasingly central to aerospace sustainability strategies, aiming to extend asset life, improve asset valuations, and enhance benefits to stakeholders in the part ownership and maintenance lifecycle. In aircraft engines, achieving circularity hinges on safe reuse, repair, and recirculation of high-value components. Life-Limited Parts (LLPs) are among the most critical in this context, but their reuse is strictly contingent on complete Back-to-Birth (BtB) traceability. Any gap in BtB records—often due to fragmented data across multiple airline operators, shop visits, document formats, and time expanse—renders otherwise serviceable LLPs unusable, leading to premature scrappage and lost circular value. This paper presents a Generative AI (GenAI)-driven methodology to reconstruct and validate complete LLP BtB histories from heterogeneous, unstructured, and legacy maintenance datasets. By combining aerospace domain-trained language models with embedded life

Bhate, Ujwal, Jain, Dilip Kumar, Kulkarni, Ninad, Kalaiyarasan, Aravindh, Jha, Ashish, Shenoy, Karthik

Sensitivity Analysis of Geometrical Imperfections in Aerospace Structures

2026-26-0738

To be published on 06/01/2026

Launch vehicle structures are designed to withstand flight loads while fulfilling their intended functional requirements. Most of these structures use cylindrical geometries and employ stiffened configurations—such as isogrid, orthogrid, or skin-stiffened designs—comprising multiple long panels to efficiently carry dominant compressive loads. Traditional FE analyses generally use simplified or idealized imperfection models, which often do not represent the imperfections present in actual hardware and therefore tend to over/under-predict load-carrying capacity based on the initial assumed imperfection level. In reality, long stiffened panels are highly sensitive to geometric imperfections introduced during manufacturing. These include spring-back effects from roll bending as well as deviations accumulated during assembly. Such manufacturing-induced variations can significantly diminish the effective load-bearing capability of the structure. The subject hardware—an isogrid cylindrical

Sharma, Amit, Singh, Nishant, Xavier, Shijo, R, Suresh

Comparative Study between MQTT 3.1 and MQTT 5.0: Evaluating Theoretical Enhancements Through Practical Throughput Benchmarks for Aerospace IoT Systems

2026-26-0711

To be published on 06/01/2026

As aerospace platforms adopt increasingly interconnected architectures for avionics, telemetry, and predictive diagnostics, lightweight publish–subscribe protocols have become integral to communication efficiency. The Message Queuing Telemetry Transport (MQTT) protocol is widely employed due to its small footprint and low network overhead. The release of MQTT 5.0 introduces new control features—reason codes, session expiry, user properties, topic aliasing, shared subscriptions, and improved error feedback—aimed at enhancing scalability and diagnostic reliability. However, these benefits come with trade-offs in complexity and potential overhead, particularly in real-time and resource-constrained environments typical in aerospace. This paper evaluates MQTT 3.1 and MQTT 5.0 within aerospace IoT contexts using a Raspberry Pi–based experimental framework. The analysis is done using practical throughput benchmarks implemented via popular open-source tools like Eclipse Mosquitto Clients

Bhuyar, Prabhudev, M, Meghana, Kaniraja, Christina, Thomas, Tinto

A GenAI-Based Approach for Real-Time Multilingual In-Flight Communication Systems

2026-26-0784

To be published on 06/01/2026

In today’s global aviation industry, passenger experience is strongly influenced by effective communication. In-flight announcements, often limited to English and a single local language, can create confusion and stress for international travelers who may not be fluent in either. This communication gap not only impacts passenger comfort but also poses potential risks in conveying time-sensitive or safety-critical information. Recent advances in Generative Artificial Intelligence (GenAI), particularly in speech recognition, neural machine translation, and naturalistic text-to-speech, provide a pathway to overcome these challenges. This paper explores the concept of real-time multilingual in-flight announcements delivered in each passenger’s preferred language through connected headphones or personal devices. The proposed system architecture integrates speech-to-text conversion, language translation, and speech synthesis with aircraft infotainment platforms. Potential applications range

Mishra, Ashwini, Kature, Kartik, Patil, Ashish

CFD Based Performance Prediction of Centrifugal Compressor

2026-26-0726

To be published on 06/01/2026

In modern engineering, compressors play a vital role across numerous industries by enabling the delivery of fluids at elevated pressures for a variety of applications, including HVAC systems, aircraft engines, and process industries. The performance of centrifugal compressors is characterized by parameters such as flowrate, efficiency, and pressure rise. Traditional methods of evaluating compressor performance, such as physical testing, are often time-consuming and costly, making them less practical for iterative design or optimization. Advancements in Computational Fluid Dynamics (CFD) have provided a faster and more cost-effective means of assessing compressor behavior. This study presents a comprehensive CFD-based analysis of a two-stage centrifugal compressor utilized in HVAC applications aimed at predicting its performance, that is, flow factor vs head factor and flow factor vs efficiency for given rotational speeds and inlet guide vane (IGV) angle positions. Focus is on

Turaga, Vijay Kumar, Aadi Gopalakrishna, Pradeep, Gugulothu, Sampath

Face Seal Gland Design, Static, O-Ring and Other Seals for Aerospace Hydraulic and Pneumatic Applications

AS6235C (Current)5/27/2026

This SAE Aerospace Standard (AS) specifies standardized gland design criteria and dimensions for static face seals for internal pressure and external pressure applications for aerospace hydraulic and pneumatic applications using the same dash size range as AS4716 and AS5857 where applicable. NOTE: Some small diameter sizes are excluded because they are not practical.

A-6C2 Seals Committee

Risk Assessment of Bunkering Process for LNG River Powered Ship

2026-99-1722

5/22/2026

At present, with the rapid development of LNG powered ships, China’s LNG powered ships have formed a certain scale, but the speed of infrastructure construction such as bunkering stations restricts the development of LNG powered ships. In this process, “tank truck-to-ship bunkering”(TTS) has become one of the most widely used bunkering methods in China because of its flexible, fast and convenient characteristics, but there are many hidden dangers in the bunkering process. According to the characteristics of TTS, fault tree method is used to identify the risk of bunkering process, and the leakage of pipeline system is listed as the basic risk factor. The leakage probability of different aperture is analyzed by industry statistics. Three different leakage scenarios are selected and the consequences are simulated by PHAST software. The study shows that the failure of the valve and flange can easily lead to the leakage of LNG in the TTS process, and the leakage of the medium aperture and

Dong, Yuanchao

BEARING, BALL, AIRFRAME, ANTIFRICTION, EXTRA LIGHT DUTY, PRECISION CORROSION-RESISTANT NITROGEN STEEL (CREN)

AS21428/1C (Current)

5/15/2026

ACBG Rolling Element Bearing Committee

Optimization of Adaptive Mesh Refinement Strategy for VOF-DPM Method

2026-99-0726

5/15/2026

When simulating spray atomization process involving VOF method, a core problem is the conflict between high grid detail and limited computer power. Although VOF and DPM methods have recently been coupled to reduce computational cost, their application in practical engineering calculations still imposes a considerable computational burden. To solve this, a better adaptive mesh refinement (AMR) plan is put forward. This plan uses a 0.2 mm initial grid (twice the usual 0.1mm) and allows refinement up to four levels. This improved technique makes high computational efficiency for large-scale simulations. Two types of nozzles are employed to evaluate the proposed method. However, for circular nozzles, the new method does not increase calculation speed, while lowers the accuracy of the simulation.In contrast, for square nozzles, it greatly boosts computation speed and keeping high accuracy. This makes the technique a useful tool for modeling transverse jet atomization in industry. Overall

Zhou, Taotao, Ma, Ming, Zhang, Haitao, Zhang, Fengan, Chen, Xianhui, Chen, Qi, Xia, Hongwei

FITTING END, 24° CONE, FLARELESS, FLUID CONNECTION, DESIGN STANDARD

AS5863A (Current)

5/15/2026

G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies

FITTING, BULKHEAD END - THREADED COUPLING, RIGID, SELF-BONDING, DESIGN STANDARD

AS5948A (Current)

5/15/2026

G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies

Rolling Element Bearing Hardness Test

ARP5483/2B (Current)

5/15/2026

This method outlines the standard procedure for testing the hardness of bearing components. Bearings covered by this test method shall be any rolling element bearing used in airframe control.

ACBG Rolling Element Bearing Committee

Research on Performance Prediction Methods for Centrifugal Refrigeration Compressors in Data Centers

2026-99-0725

5/15/2026

As the “digital brain” and core foundational support for the development of intelligent transportation and connected vehicles, the performance of data centers directly determines the operational capability of intelligent transportation systems. In the process of advancing the vehicle-road-cloud collaborative architecture, the demand for high-performance computing power in data centers has experienced explosive growth. The substantial increase in computing tasks has posed severe challenges to thermal management, making efficient and reliable cooling systems an indispensable core component. Centrifugal compressor water-cooling units are the mainstream cooling solution for large-capacity scenarios, and their design optimization is crucial for improving the energy efficiency and performance of the entire cooling system. This paper proposes a one-dimensional performance prediction method for centrifugal compressors based on an empirical loss model, and realizes the iterative calculation of

Zhu, Minhao, Jiang, Bin, Li, Min, Zeng, Zihui, Gu, Yunhui

Adaptive Speed-Regulated Impedance Control for Robotic Ultrasound Scanning: Reducing Constant-Force Tracking Errors

2026-99-0751

5/15/2026

Robotic ultrasound scanning technology is a research hotspot in the field of medical imaging, and can achieve standardized and high-precision data acquisition. However, large force tracking errors occur during scanning, especially in complex human tissues, which can severely degrade image quality and diagnostic accuracy. Therefore, we propose an adaptive speed-regulated impedance control strategy to address this challenge, which innovatively combines the spline real-time interpolation and impedance control for constant force tracking. Firstly, the discrete ultrasound scanning paths are fitted to generate a smooth and synchronized interpolation trajectory. Then, the speed of the reference trajectory is adjusted in real time based on the Taylor formula to reduce the force tracking error. Experimental verification was conducted, and the results showed that the force tracking error increases with the increase of trajectory speed. In addition, at high speeds (e.g., 10 mm/s), the mean

Min, Kang, Zhang, Le, Shi, Yudong, Fang, Jin, Mo, Hangjie, Li, Xiaojian

Design of a Modular High-Power High-Repetition-Rate Semiconductor Pulsed Laser Power Supply

2026-99-0716

5/15/2026

μsμs

Huang, De, Lu, Jiawei, Yang, Zhiqing, Xv, Ziyi, Xing, Hui

Contractile Strain Ratio Testing of Titanium Hydraulic Tubing

AS4076A (Current)

5/11/2026

This SAE Aerospace Standard establishes the requirements and procedures for Contractile Strain Ratio (CSR) testing of cold-worked and stress-relieved titanium tubing such as Ti-3AI-2.5V tubing per AMS 4944.

G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies

BOLT, MACHINE - DOUBLE HEXAGON, EXTENDED WASHER HEAD, CLOSE TOLERANCE SHANK, UNS N07001, 165 KSI, .3750-24 UNJF-3A

AS9726A (Current)

5/7/2026