Browse Topic: Seals and gaskets

Items (3,340)
In this work, three-dimensional models of axial hole labyrinth-honeycomb seals (AHLHS) and circumferential hole labyrinth-honeycomb seals (CHLHS) were established by CFD to investigate the influence of different arrangement patterns on the static stability and leakage characteristics of two seals under choked and unchoked flow conditions and various eccentricities with different values. The results show that the two configurations have different advantageous ranges, and the hole arrangement pattern will not significantly change the pressure difference distribution between the two seals. Under most studied conditions, AHLHS maintains lower absolute values of stiffness coefficients, pressure difference groove, and negative cross-coupled stiffness coefficients, resulting in higher stability.
Li, Qing’anGao, TongxinLi, ZezePang, ShuaiLü, YanjunZhang, Yongfang
The Core Module of the space station is the first module of China’s Space Station, responsible for controlling the key parameters such as orbit, speed, and pressure of the entire space station, and serving as the control center of the assembly. The Solar Array Drive Assembly is a part of the Core Module. It needs to participate in the functional requirements of the whole cabin sealing of the cabin body, so it adopts the design scheme of semi-sealed. By adjusting the compression ratio and volume fraction of the sealing ring, and the roughness of the sealing surface, the overall sealing performance is improved. A small cavity leak detection hole is added to realize the sealing effect of detecting the second-layer seal separately. The real leakage rate of the drive mechanism is detected effectively by using multiple calibration schemes in the leak detection process, and the semi-sealing technology of the Solar Array Drive Assembly is verified, which has guidance and reference significance for the subsequent spacecraft design requiring a sealing function.
Dai, FeiZhu, JiahaoHuang, MengzheQian, Zhiyuan
With the continuous development of large precision equipment, the reliability requirement for long-distance transportation is also constantly increasing. Large packaging box with sealing and vibration reduction performance is crucial during transportation. This article introduces the sealing measures for large-sized packaging box, as well as the sealing structure design methods for key parts, vibration reduction measures and the selection and design of vibration dampers. The designed packaging box has been used for long-distance transportation of various types of equipment and the reliability of sealing and vibration reduction performance has been verified in practical applications, providing reference for the design of similar packaging boxes.
Zhang, RuoyuJiang, Shouli
Noise phenomena in automobiles caused by the stick-slip effect are increasingly among the most frequent reasons for customer complaints and therefore represent a critical vehicle quality attribute. To proactively address such issues, stick-slip testing of contacting material pairs is commonly applied during development. However, the predictive capability of current stick-slip test methods remains limited, particularly when highly flexible materials and realistic, stochastic excitation conditions are involved. The flexibility of sealing systems often allows the actual relative motion at the contact interface to be accommodated through adhesion and elastic deformation, thereby delaying or even preventing sliding. To date, this effect has not been represented by any characteristic parameter in conventional stick-slip testing. Instead, existing evaluations focus exclusively on the analysis of occurring stick-slip oscillations. For the initiation of stick-slip phenomena, however, not only the mean displacement between two stick-slip oscillations during the sliding phase is relevant, but also the relative displacement required to initiate the first slip event of the sealing contact. With the algorithm developed in this work, which reproducibly determines the distance to first slip based on changes in the friction force slope, this methodological gap is now closed. The displacement to first slip depends on numerous influencing factors, including profile geometry, normal load, sliding velocity, excitation profile, and environmental conditions, and was previously inaccessible by both experimental and numerical approaches. In particular, the onset of slip in sealing contacts can now be determined under stochastic excitation of the friction pairing, thereby closely reflecting real operating conditions. As a result, the prevention of noise phenomena can be significantly strengthened at an early stage of vehicle development.
Strangfeld, MartinFritz, SusanneWeber, JensRosell, Anneli
This document recommends standard gland design criteria and dimensions for dynamic radial O-ring seal applications specifically for engine and engine control systems operating at pressures up to a maximum of 1500 psi (10342.14 kPa) and provides recommendations for modifying these glands in special applications. There are no provisions in this document for anti-extrusion devices. NOTE: The criteria set forth here are similar to but not identical with those in MIL-G-5514 and AS4716. This document is not intended to replace MIL-G-5514 or AS4716 for hydraulic applications.
A-6C2 Seals Committee
High-temperature hydraulic control in a Formula 1 drivetrain requires dimensional stability, controlled sealing force, and resistance to wear under sustained pressure cycling. Inside the limited-slip differential, the sealing architecture plays a defined mechanical role in maintaining consistent torque management under race conditions. In Formula 1, drivetrain reliability and performance are closely linked. The limited-slip differential (LSD) governs torque distribution between the rear wheels, allowing controlled transfer of power to the wheel with greater available grip. By limiting speed difference across the rear axle, the differential contributes directly to traction and cornering behavior, particularly where grip levels vary across the vehicle. At the center of this assembly is a hydraulic actuator that clamps a friction clutch inside the differential. The actuator modulates clutch engagement to redirect torque as grip levels change through corner entry, mid-corner load transfer, and acceleration on exit. Its performance depends on precise hydraulic control, which in turn depends on sealing integrity. Within this system, seal integrity is paramount, as significant leakage could cause a catastrophic loss of system function and force the team to retire the car.
Clarke, Andrew
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 Hardness change, were assessed through precision measurement techniques. Weight changes before and after immersion were also recorded to correlate material absorption characteristics with the success criteria. Success thresholds were established based on industry requirements for seal integrity and operational reliability. Preliminary results indicate that FKM exhibits minimal volume expansion and hardness change under specified conditions, aligning with the acceptance criteria. These findings support the suitability of FKM seals for long-term use in coolant systems, with implications for material selection and design in demanding applications. This research contributes to the development of durable sealing solutions, ensuring reliability and safety in systems utilizing ethylene glycol-based coolants. Keywords: FKM, Volume Expansion, ASTM D471
Yarolkar, MakrandPatil, SandipSingh, Tanul
Sealing systems in space applications must perform reliably under demanding conditions in engineering: cryogenic temperatures, vibration, leakage control, ultra-high vacuum, ionizing radiation, abrasive particulates, and repeated thermal cycling. Each factor strains conventional sealing technologies. In combination, they can rapidly cause failure in systems where margins are unforgiving and maintenance is impossible. As spacecraft architectures evolve toward longer operational lifetimes and broader mission profiles, sealing requirements continue to tighten. Launch vehicles, satellites, and exploration platforms now operate across wider temperature ranges and in contact with more aggressive propellants and media. As a result, both metal seals and engineered polymer alternatives are evaluated-and selected-against increasingly specific, measurable performance criteria.
A computational study using the Volume of Fluid (VOF) method in SimericsMP+ was conducted to investigate fuel sloshing in automotive fuel tanks under both crash and sudden stop conditions. The SEALs method was employed to rapidly generate the fuel tank mesh, enabling efficient simulation setup. At the outset, a benchmark sloshing case was simulated and compared against experimental data, showing excellent agreement to validate the simulation method. This simulation method was then applied to the fuel tank sloshing scenarios mimicking crash and sudden stop conditions. The study initially focused on a crash scenario in which fuel waves impact valves, pumps, and other internal structures. Capturing these localized impact forces is critical for evaluating the risk of component failure and potential leakage. A baffle-equipped tank was simulated and compared with sensor data. Results show that the computed shock forces on valves and baffles closely matched the measurements, demonstrating the high accuracy of the CFD method in predicting crash safety performance and confirming the effectiveness of baffles in reducing fuel wave impacts. The validated framework was then applied to four new unbaffled tank designs to assess NVH performance during low-speed sudden stop maneuvers. Pressure fluctuations on tank walls, which are directly linked to cabin noise, were analyzed and compared against reference pressure measurements from physical tests to ensure compliance with NVH standards. Simulations revealed significant pressure peaks in certain designs, indicating sub-optimal acoustic performance and highlighting how the absence of internal columns or baffles amplifies wave propagation and surface loading. The computational strategy presented in this study provides a powerful tool for evaluating both crash safety and NVH behavior early in the design process. By delivering accurate predictions before physical prototypes are built, it helps guide fuel tank design development, reduces reliance on costly testing, and minimizes the risk of late-stage design failures.
Jia, KunRahman, AshiquePandey, Ashutosh
This standard presents the designer with sufficient information to fully define the configuration of the connection and to determine the limits of application for given conditions.
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
How engineers can ensure safety, reliability and quality in aerospace systems. Courbevoie, Île-de-France In an industry where failure is not an option and precision is paramount, aerospace manufacturers and suppliers are constantly seeking components and system solutions that deliver trusted reliability, performance, and compliance. Industry standards are a key part of achieving these high expectations, bringing together global leaders in the mobility industries to create defined, repeatable methods and consistent processes. One of these aerospace standards is AS1895 developed by SAE International - a critical standard due to the need for durable components that can withstand extreme conditions and offer high performance: high-temperature resistance, pressure sealing, and long service life with a cost-effective installation method. Leading aerospace companies such as Eaton and Honeywell have been manufacturing components that meet this standard for a long period of time.
This SAE Aerospace Standard (AS) specifies the inside diameters, cross-sections, tolerances, and size identification codes (dash numbers) for O-rings used in sealing applications and for straight thread tube fitting boss gaskets. The dimensions and tolerances specified in this standard are suitable for any elastomeric material provided that suitable tooling is available.
A-6C2 Seals Committee
This procurement specification covers aircraft quality metallic gaskets having a "C" shape cross-section to form a seal ring, made from a corrosion and heat resistant age hardenable nickel base alloy of the type identified under the Unified Numbering System as N07750.
E-25 General Standards for Aerospace and Propulsion Systems
This standard provides the following: a The required surface finish criteria for the designed function of the parts b The definition of surface imperfections and defects that affect surface quality c The categories by location for each geometry for the permissible type, size and quantity of defects It also establishes the quantitative levels of acceptance by providing defined limits and inspection guidance for the acceptance or rejection of production parts This specification is applicable but not limited to, the surface quality of: T-Seals L-Rings Capped T Rings Capped L Rings Cammed Type Seals Cruciform Shaped Elastomers Pyramid (Dyna-Bak) Seals Square Ring Seals Quadruple Lobed Seals U-Cups Spring Energized U-Cups Molded in Place Metal Gasket Seals
A-6C2 Seals Committee
Improving transaxle efficiency is vital for enhancing the overall performance and energy economy of electric vehicles. This study presents a systematic approach to minimizing power losses in a single-speed, two-stage reduction e-transaxle (standalone) by implementing a series of component-level design optimizations. The investigation begins with the replacement of conventional transmission oil with a next-generation low-viscosity transmission fluid. By adopting a lower-viscosity lubricant, the internal fluid resistance is reduced, leading to lower churning losses and improved efficiency across a wide range of operating conditions. Following this, attention is directed toward refining the gear macro-geometry to create a gear set with reduced power losses. This involves adjustments to parameters such as module, helix angle, pressure angle, and tooth count, along with the introduction of a positive profile shift. These modifications improve the contact pattern, lower sliding friction, and achieve a more uniform distribution of forces along the gear flanks. As a result, load-related gear losses are significantly diminished. In the final stage of optimization, high-performance, low-friction bearing designs are incorporated to further reduce mechanical drag and enhance overall drivetrain efficiency. For bearing loss optimization strategies, energy-efficient ball bearing designs is examined and engineered to lower internal friction and increase operational lifespan. Energy Efficient bearing prove significant improvement in efficiency and further reducing mechanical losses within the drivetrain. Taken together, the findings highlight that careful selection of lubricants, refinement of gear geometry, and adoption of advanced bearing solutions can deliver notable gains in transaxle efficiency. These outcomes reinforce the potential of such targeted interventions as practical means for boosting drivetrain performance in electric vehicle applications.
Agrawal, DeveshBhardwaj, AbhishekBhandari, Kiran Kamlakar
In tractors, efficiency is predominantly influenced by the transmission system, with transmission elements being the major contributors to power losses. Enhancing efficiency necessitates monitoring these power loss areas. Transmission power loss refers to the reduction in power from the engine to the final drive elements. Various parameters and factors affect these losses, and analyzing these conditions helps identify and improve the components that contribute most to driveline efficiency. This study correlates analytically calculated power loss with losses measured during testing under different load conditions. Additionally, critical parameters contributing to power loss in gears, bearings & in seals have been identified, and theoretical relationships have been established.
Jayapal, JayarajMahapatra, Soumya RanjanSethi, Suvendu KumarJoshi, ShrikantBange, Prashant
Manufacturing tolerances play a critical role in the quality and functionality of components, particularly those made from rubber. Even slight deviations in dimensions can cause significant issues such as improper fit and reduced performance, leading to increased costs and project delays. This is especially true for rubber grommets, which are nonlinear elastic components commonly used as sealants, gaskets, and insulation covers in automotive and industrial applications. Typically manufactured from EPDM rubber with varying Shore hardness, grommets must maintain precise geometry to ensure sealing integrity and protect adjacent parts. Dimensional inaccuracies can result in failures such as buckling or misalignment, compromising both functionality and durability. This study proposes a digital simulation methodology for early-stage evaluation of grommet robustness, reducing reliance on physical prototypes. Using a stochastic design of experiments (DOE) approach, the influence of critical geometric parameters on grommet performance is assessed under variable manufacturing conditions. Buckling, identified as the primary failure mode, along with other functional metrics, is analyzed across a spectrum of dimensional tolerances. These insights support more efficient design workflows and enhance the robustness of rubber grommets in real-world applications.
Beesetti, SivaHattarke, MallikarjunJames Aricatt, JohnPathan, Eram
The automotive market trend is shifting more and more to SUVs and crossovers. This, therefore, means increasing consumer demand for off-road abilities in passenger vehicles. While dedicated off-road platforms provide a path to performance robustness, getting the same level of functionality out of a passenger vehicle with minimal architectural changes proves to be a great feat for engineers. One highly critical performance determinant in the domain of off-road ability is wheel articulation, it requires independent movement capacity of the wheels to keep contact and stability over uneven terrain. Traditional articulations found in passenger car suspensions—created for comfort, packaging, and on-road dynamics—are limited by suspension geometry, damper alignment as well as compliance setup. Damper side loads- were not considered a significant factor in suspension systems that are operating within their original intended design envelope for on-road use. However, when the vehicle is taken off-road, extreme conditions lead to lateral forces during an unseated exaggerated wheel travel, these can result in seal degradation as well as rod bending increasing friction (stiction) leading ultimately to damper failure. Seal durability and general component integrity are not the only issues increased side loading will decrease articulation reduce traction and degrade ride quality during severe terrain inputs. Articulation- is essentially a measure of flexibility in the suspension which directly controls off-road performance characteristics. With limited articulation there is wheel lift traction loss and increased chassis contact. A major limitation to achieving full articulation is damper side load-the perpendicular force to the damper shaft created from angular misalignment in suspension travel. This also increases the compressive stress on the damper rod. Therefore, an optimization of the rod diameter, length, and material is required. The Ramp Travel Index (RTI) is a means of expressing articulation by using the measure of ramp height that can be attained by a vehicle climbing with one wheel while maintaining contact with others. A high RTI indicates good off-road capability. There exists an interrelationship between suspension geometry, damper side load characteristics, and axle alignment in determining off-road performance; this paper proposes an optimization guideline to overall improve wheel articulation specifically for passenger vehicles through these parameters: wheel travel, suspension hard points, and damper mounting orientations.
Siddiqui, ArshadIqbal, ShoaibDwivedi, Sushil
In today's dynamic driving environments, reliable rear wiping functionality is essential for maintaining safe rearward visibility. This study sharing the next-generation rear wiper motor assembly that seamlessly integrates the washer nozzle, delivering improved performance alongside key benefits such as better Buzz, Squeak, and Rattle (BSR) characteristics, reduced system complexity, cost savings, and enhanced perceived quality. This integrated design simplifies the hose routing which improves the compactness and the efficiency of the design. This also enhances the spray coverage and minimizes the dry wiping unlike the traditional systems that position the washer nozzle separately. A non-return valve (NRV) is incorporated to eliminate spray delays ass it maintains consistent water flow giving cleaning effectiveness. Since this makes the nonfunctional parts completely leak proof due to the advanced sealing, it increases the durability and reliability in long run. As this proposal offers a sustainable solution, it can be considered as the new benchmark in rear wiper technology.
Dhage, PrashantK, NagarajanG, Sabari Rajan
This paper presents the design, structural analysis, structural test validation and risk assessment done by Cummins to evaluate the structural integrity of Light Duty engine cylinder head for a Medium Wheelbase (MWB) pick-up truck. Initially, Cummins used the 2.5L and 3.0L (4-cylinder) engines that have standard power ratings based on existing requirements, but rising market demands for more power, fuel efficiency, lower cost and weight, and future emission compliance led to customer requirements for 15% uprate for 2.5L and 22% uprate for 3.0L from the same base engine. The increase in power requirement possesses challenges on critical components, especially cylinder heads in terms of thermal and structural limits. Multiple analysis led design iterations were performed using cutting edge CAE software such as Ansys, Dassault Systems fe-safe, and PTC Creo to ensure the structural integrity of the cylinder head under high thermal and mechanical loads, and to keep design margins within acceptable limits. A key feature identified through topology optimization was diagonal ribbing pattern on each cylinder, which is novel, and similar pattern can be applied to both new and existing engine platforms to enhance stiffness without major changes to the water jacket. The Cylinder head was subjected to a long endurance test, which comprises of high thermal and mechanical loads under extreme operating conditions. After running for specified number of hours as per inhouse test requirements, the engine was stopped for magnetic particle inspection for any signs of fatigue failure. No major cracks were observed on the 3.0L Cylinder head combustion face. However, a few cracks were observed on the 2.5L cylinder head combustion face at exhaust & intake bridges. Upon investigation, it was concluded that crack was due to high thermo-mechanical fatigue loads and hence further optimization was carried out on the cylinder head design. Furthermore, cylinder head gasket coolant orifice optimization is done to improve the coolant distribution to each cylinder. Thermal analysis showed a reduction in exhaust & intake bridge temperature within the acceptable limits. This paper captures the detailed design and structural analysis on 3.0L and 2.5 L diesel engine Cylinder head.
Pathak, Arun JyotiAdiverekar, VaidehiSingh, RahulBiyani, Mayur
Internal Combustion Engine (ICE) is the heart of an Automobile. The failure of any critical component of the ICE engine will directly affect the performance of the vehicle. The gaskets are among the many vital parts of an IC engine that are essential in ensuring appropriate sealing to prevent gas and liquid leakage and maintain optimal engine efficiency. Engines use a variety of gasket types to accommodate various sealing requirements. Among them the exhaust manifold gaskets are one of the critical gasket elements in ICE engines. Exhaust Gasket acts as a seal between cylinder head and extremely hot exhaust manifold, which prevents the leakage of hot exhaust gases produced during typical engine operating condition. The gaskets are crucial components because they endure extremely high mechanical loads from the exhaust manifold sliding and banana-shaped bending brought on by thermal expansion, as well as extremely high thermal loads from the high exhaust gas temperatures, which are more than 800°C. These gaskets are additionally subjected to extremely high bolt loads. As the gaskets are made of steel materials, due to the above Thermo-Mechanical loads, there are very high chances for wear out of the gaskets, which affects the performance characteristics & thus efficiency of the engine. Study of wear phenomenon is very challenging particularly for the gaskets because of nonlinear behavior of geometries, material nonlinearities and in addition, the gaskets are made up of numerous layers with negligible thickness, which makes it further challenging. The wear in Automobile Engine components and particularly in gaskets is an area, which has not been studied extensively. This paper majorly focuses on a computational approach to capturing the wear phenomenon on the gaskets. One of the most critical hot end durability tests of the engine was replicated in a simulation environment by considering all the relevant physics from the physical test. To simulate wear phenomenon, the classical Archard’s wear model was implemented in a UMESHMMOTION Fortran subroutine code and solved in the Finite Element Software ABAQUS/Standard. To consider the removal of material and geometry change due to wear, the Arbitrary Lagrangian-Eulerian meshing technique of ABAQUS was used.
Reddy, RajavardhanR B, GovindKulkarni, SanjeevPalve, ChandrakantMueller, Frank Oliver
Quieter cabins in an automobile are the new era, they provide customers with pleasurable driving experience. Squeak and Rattle are spoil sport for any OEM that aim to improvise customer driving experience. Their nonlinear nature makes it difficult to formulate design frontloading methods. The issue of seals rubbing against the body & door interface is a clear sign of seal squeak & seal chucking. Seals are applied with anti-friction coatings to avoid stick slip phenomena between EPDM and painted panel. Primary root cause for seal squeak is coating erosion. The challenge lies in determining whether the body or the closure side contributes to the seal issue. This paper presents a distinctive approach for identifying the seal squeaking noise and enriches on the new modelling methods for seal interaction with door and body interfaces using FE software. The proposed method was able to highlight the locations along the door-body interface for squeak noise. The approach for reducing the relative displacements was tackled by checking the contributing modes at every interface. A simulation-driven approach of “Panel Contribution Analysis” (PCA) has been introduced analyzing the contribution of several BIW & Closure panels. The optimized panel thicknesses minimized the displacement and reduced the likelihood of squeaking and chucking. The key highlight is a method of DOE followed to minimize experimental runs with a weighted optimization of panel thickness. This method enables engineers to achieve the ideal trade-off between structural integrity, weight, cost, and performance.
H, RavishankarC M, MithunMichael Stephan, Navin Estac RajaMohammed, Riyazuddin
The widespread adoption of electric vehicles (EVs) has introduced distinct engineering challenges, particularly in the design of battery packs, which are crucial for vehicle performance, safety, and longevity. A critical requirement is maintaining ingress protection (IP) ratings of IP67 or higher to protect the high voltage battery packs against water and dust exposure. These ratings are crucial for ensuring compliance with homologation standards and meeting the demands of diverse terrains and operating conditions. Consequently, achieving effective sealing of EV battery packs is a fundamental aspect of their design and engineering. This study presents a comprehensive analysis of sealing technologies employed in EV battery packs, focusing on four primary types: adhesive-based sealants, Formed-In-Place Gaskets, foam cut seals, and rubber gaskets. Benchmarking data collected from over 100 vehicle models across more than 50 brands provides insights into adoption trends, historical shifts, and the evolution of sealing technologies within the EV industry. The study examines potential reasons driving the choice of specific sealing methods, considering factors such as material properties, manufacturing costs, ease of application, and design considerations. While the analysis is based on industry trends and technical knowledge, it acknowledges that inferred strategies and preferences may differ slightly from the actual intentions or proprietary decisions of original equipment manufacturers (OEMs). Ultimately, this paper serves as a benchmark resource for researchers and industry professionals, offering critical insights into trends, challenges, and innovations in achieving optimal sealing performance for EV battery systems.
Varambally, VishakhaSithick basha, AbubakkerChalumuru, MadhuYaser, K U SyedSasikumar, K
This study focuses on the effect of door seal compression prediction and its impact on structure borne NVH in trucks. Customer perception of vibrations are envisaged as quality criteria. It is necessary to determine the contribution of seal stiffness due to seal compression under closed condition of the door rather than considering stiffness of the door seal under uncompressed conditions. The dynamic stiffness of door seal is determined from analysis of non-linear type. The simulations are built using the Mooney - Rivlin model. The parameters influencing the compression of door seals in both two – dimension and three – dimension, are identified from the analysis. This involves contemplating the appropriate seal mounted boundary condition on the body and the door of the vehicle. The stiffness after compression of seal is extracted from this non-linear analysis which is further used to obtain the vibration modes for the doors in the truck cabin. As a part of next step, the compressed seal stiffness value is used to analyze the operational vibration and structure borne cabin noise. The simulated results for modal performance including the effects of seal are validated with the experimental test data and are noticed to be in good agreement. The simulated result of models that were analyzed with the use of both uncompressed seal data and compressed seal data are compared for operational vibration, operational noise respectively. It is observed that the compressed seal stiffness has an impact on the structure borne NVH performance of the truck cabin.
L, KavyaRamanathan, Vijay
Nitrile Butadiene Rubber (NBR), known for its superior resistance to hydrocarbon oil, low gas permeability, and excellent thermal stability, finds extensive use in seals, O-rings, conveyor belts etc. Importantly, these performance attributes are chiefly governed by acrylonitrile content in NBR. Analytical characterization of raw NBR is relatively straightforward using conventional techniques such as elemental analysis (CHNS) and liquid state 13C NMR. In contrast, the analysis of vulcanized NBR presents considerable challenges due to its crosslinked structure, which renders it insoluble in most organic and inorganic solvents, thereby restricting direct molecular-level analysis. While solid-state 13C NMR is an established technique for structural characterization in rubber vulcanizates, its high-cost curbs routine industrial analysis. In this study, Pyrolysis-Gas Chromatography-Mass Spectrometry (Py-GC-MS) technique has been explored as a robust, precise, cost-effective alternative. Quantitative determination of acrylonitrile (ACN) content in vulcanized NBR, covering a compositional range of 15% to 52% is carried out using Py-GC-MS. For sequence distribution of ACN units, liquid-state 13C NMR, is utilized exclusively for soluble, uncured NBR. The absolute ACN content values thus obtained serve as reference standards for validating the Py-GC-MS method, enabling robust quantification across both raw and cured material forms.
Samanta, RajyasreeGhosh, DebojitAnjana, KanhaiyaSen, AmitGuria, BiswanathChanda, JagannathSamui, BarunGhosh, PrasenjitMukhopadhyay, Rabindra
Water leakage is a common issue in vehicles, especially during water testing. It often occurs due to a gap between the seal bulb and the closure panel. This gap can result from variations in flange angle, flange curvature, closure surface, or seal bulb height. This study focused on how flange curvature affects seal bulb height and sealing performance. A Computer-Aided Engineering (CAE) method was used, supported by tests on physical samples. Multiple simulations were done using different flange curvatures. Results showed that with a constant Side View Flange Angle (SVFA) of 150°, increasing the Flange Curvature Radius (RZX) reduced seal bulb deformation. The optimal flange curvature radius was found to be 250 mm, where the bulb compression was 1.2 mm. Sharp or tight flanges caused the bulb to deform more, reducing contact and sealing force. To reduce this deformation, a hollow tube was inserted inside the seal bulb. The hollow tube used had an internal diameter of 10 mm and an external diameter of 12 mm. With the hollow tube, the optimum flange radius dropped to 100 mm. At this point, the seal bulb collapse height improved by 66.16%, and Compression Load Deflection (CLD) increased by 250%, which may increase the door closing efforts. Further improvement was made by changing the hollow tube material from sponge Ethylene Propylene Diene Monomer (EPDM) with Specific Gravity (SG) 0.6 to a super soft solid sponge EPDM with SG 0.25, optimizing the CLD to 180%. CAE results showed 90% correlation with physical tests for seal bulb deformation, and 85% for CLD, for all seal variants. This research can help in optimizing seal bulb height, sealing gaps, sealing force, and especially flange curvature and angle during the early design stage of vehicle apertures. This method enables automotive engineers and researchers to minimize costly late-stage design changes and achieve a right-first-time seal and Body-in-White (BIW) structure.
Kumar, SauravNeelam, RajatChowdhury, AshokPanchal, GirishLathwal, Sandeep
The article presents self-adjusting segmented ceramic seals designed for a novel turboshaft engine operating according to the Humphrey thermodynamic cycle. The sealing system is an integral part of the developed engine concept, which features rotating isochoric combustion chambers. The seals utilize centrifugal force as the sealing force, enabling uniform sealing regardless of thermal conditions and associated deformations. The sealing consists of segments with adjustable dimensions in both circumferential and transverse directions. The sealing elements should be made of Si3N4 ceramic, characterized by high thermal resistance (1300°C) and low thermal expansion (3.2•10−6/°C). The article presents three different variants of sealing systems, differing in terms of the technological possibilities of their manufacturing. Special treatments must be applied to ensure high machining accuracy of the sealing elements. The proposed sealing system is a critical point in the design of an engine with isochoric combustion chambers. Successful sealing is key to the implementation of the Humphreys thermodynamic cycle, which offers higher engine efficiency compared to classical turboshaft engines available on the market. The article concludes with the presentation of a model for experimental investigations, along with its thermal analysis.
Tarnawski, Piotr
This paper presents an analysis methodology developed to comprehend the impact of pressure spikes in off-highway applications, particularly during PTO (Power Take-Off) clutch engagement. These pressure spikes can adversely affect hydraulic subsystem components such as seals, gaskets, and valve operations. Assessing hydraulic system performance through physical trials can be cumbersome, resulting in longer development times and increased costs. To address this, a methodology was developed in a virtual environment to evaluate hydraulic system performance. The virtual method outlined in this paper is created in a 1D environment using a simulation methodology to replicate the transient behavior of the dynamic system. The hydraulic system primarily includes a relief valve, solenoid valves, a pump, and a clutch. An analytical model was developed for the hydraulic system components with appropriate fidelity to accurately replicate the transient behavior and magnitudes of pressure spikes. This methodology has been validated by instrumenting the vehicle, yielding a strong correlation of over 90% with the acquired data. The correlated analytical model was then leveraged to conduct a Design of Experiments (DOE) on various subsystem components, including accumulators, orifices, and engagement rates, to analyze their effects on hydraulic system pressure spikes. This methodology has facilitated the development of an analytical workflow to optimize the system early in the product development cycle.
Memane, NileshKumar, SuneelVeerkar, Vikrant
This specification covers a fluorosilicone (FVMQ) rubber in the form of molded rings.
AMS CE Elastomers Committee
This specification covers an acrylonitrile-butadiene rubber in the form of molded rings, compression seals, O-ring cord, and molded-in-place gaskets for aeronautical and aerospace applications.
AMS CE Elastomers Committee
Plastic materials are used for a wide variety of spacecraft applications including seals, bearings, fasteners, electrical insulators, thermal isolators, and radomes. Selecting plastics for use in space is complex due to wide operating temperature ranges, vacuum conditions, and exposure to radiation and atomic oxygen. Additionally, some spacecraft applications require sealing flammable propellants such as hydrogen and oxygen. This article will present some design considerations when selecting plastics for use in spacecraft. It will provide rich data on the performance characteristics of plastics as well as examples of successful spacecraft applications.
Power steering pumps are the heart of any hydraulic power steering system. They provide the heavy lifting power required in the form of high-pressure fluid flow that is utilized in powered steering gears or steering racks to assist drivers in vehicle maneuvers, specifically in low-speed situations. Failure of the power steering pump will inevitably increase work needed from the driver to steer a vehicle and decrease the driver comfort at the same time. This article covers investigations into a customer return issue, affecting more than 20% of pumps, for one particular failure mode, pump input shaft seal leakage, and how the failure is not caused by failure at the input shaft nor by failure of the input shaft seal. It was found that internal damage to the pump rotating assembly allows high-pressure oil to overcome the input shaft seal sealing effect. The cause of the failure was determined to be rooted in the manufacturing process, which was re-ordered to reduce the failure rate to an acceptable value (<1%).
Bari, Praful RajendraKintner, Jason
This standard establishes the dimensional and visual quality requirements, lot requirements, and packaging and labeling requirements for O-rings molded from AMS7274 rubber. It shall be used for procurement purposes.
A-6C2 Seals Committee
This standard establishes the dimensional and visual quality requirements, lot requirements, and packaging and labeling requirements for O-rings machined from AMS3617 polyamide material. It shall be used for procurement purposes.
A-6C2 Seals Committee
This standard establishes the dimensional and visual quality requirements, lot requirements, and packaging and labeling requirements for O-rings machined from AMS3650 material. It shall be used for procurement purposes.
A-6C2 Seals Committee
This SAE Aerospace Standard (AS) specifies the dimensions, tolerances and size codes (dash numbers) for O-rings with a larger cross-section than those to AS568, for use in glands per MIL-G-5514 where squeeze at low temperature is often insufficient to provide a leak-tight seal.
A-6C2 Seals Committee
This specification controls surface condition, manufacturing defects and inspection requirements, and defines methods of measurement for elastomeric toroidal sealing rings (O-rings) for static (including gasket) applications.
A-6C2 Seals Committee
This specification and part standard specifies polytetrafluoroethylene (PTFE) resin material and the dimensional requirements for scarf-cut retainers (backup rings) previously specified by MIL-R-8791 and MIL-R-8791/1. The retainers are intended for use in hydraulic and pneumatic system components as anti-extrusion devices in conjunction with seals and O-rings.
A-6C2 Seals Committee
This SAE Aerospace Standard (AS) provides a standardized test procedure that can be used to evaluate material capability in a dynamic sealing application. This procedure will be utilized by applicable elastomer material specifications which are used for production of O-rings and other seals. This specification is applicable to the dynamic testing requirements for aerospace elastomer parts utilizing materials conforming to AMS7XXX series specifications, user specifications, or print on a Purchase Order (PO) that calls out this document for aerospace applications. This procedure is intended for testing NBR. Other elastomers may have different requirements which will require a separate procedure.
AMS CE Elastomers Committee
This aerospace test standard establishes the requirements and procedures for evaluating and comparing the impulse fatigue performance of high pressure hydraulic fittings and tubing. This test method may be used to test similar fluid system components, if desired.
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
This document recommends standard gland dimensions for static radial O-ring seal applications specifically for engine and engine control systems and provides recommendations for modifying these glands in special applications.
A-6C2 Seals Committee
The reliability and performance of steering systems in commercial vehicles are paramount, given their direct impact on reducing hazardous driving and improving operational efficiency. The torque overlay system is designed to enhance driver control, feedback, and reduce driver fatigue. However, vulnerabilities such as water ingress under certain environmental conditions have raised significant reliability requirements. This article discusses the systematic investigation into how radial bearing sideloading led to the input shaft seal failing to contact the input shaft. Water was allowed a path to enter the TOS module, affecting the electronic sensor, and faulting out the ADAS functionality. Improvement to the bearing support and sealing design culminated to an enhanced TOS module package able to withstand testing procedures that mimic the environmental and use case situation which caused the ingress.
Bari, Praful RajendraKintner, Jason
This document establishes standard gland design criteria and dimensions for static axial O-ring seal applications without anti-c operating at a maximum pressure of 1500 psi (10345 kPa).
A-6C2 Seals Committee
Different types of gaskets are being used in the engine. Each gasket plays a unique role for the application. In general gaskets are used to prevent leakage and fill the space between the mating surfaces under compression loads. Cylinder head cover gasket is being used in all engines. Engine gasket plays a major role in arresting and protecting the leakage of oil and external dust entry into the system. In this study new cost-effective material were identified, tested, and evaluated as per the applicable standards for the gasket application. The existing material is well known grade as VAMAC—ethylene acrylate monomer (AEM) material and the alternate material introduced is high temperature alkyl acrylate copolymer (HT ACM). In general, with AEM material have its own advantages and also challenges. Even though AEM material have some advantages with respect to temperature and mechanical properties the challenges and struggle come into picture on cost volatility and availability of raw material. The above reasons are always risks on the product and reputation. For the proposed material these challenges were taken care and addressed and also the material selected as per engine gasket application requirement. The proposed HT ACM material cost will be 40% lesser than the existing AEM material. Also with respect to supply chain there are multiple RM sources for proposed HT ACM material including M/s Zeon, M/s Unimactec, M/s OSAKA, and so forth. Both AEM and HT ACM materials underwent validation at both the material and assembly levels. This included testing their mechanical, physical, and thermal properties. For application-level testing, samples were assembled at the engine test bed to evaluate durability and endurance cycles. The results indicated that the HT ACM material met all the application requirements with respect to material and part level validation.
Deepalakshmi, R.Koorella, KrishnaSivakumar, G.K.
When a vehicle is driven at high speed, there exists intricate flow pattern and vortex shedding at the side window area with intense pressure fluctuation. A significant dynamic pressure difference between the vehicle's exterior and interior can render the side window sealing system vulnerable to aspiration. This susceptibility can lead to the generation of leakage noise, adversely affecting acoustic comfort in the vehicle's cabin. This paper delves into the aspiration properties of glassrun seal system under time-varying pressure difference. A nonlinear finite element model of the glassrun seal was established to simulate the quasi-static deformation of the sealing strip during installation process, which aims to obtain the deformed geometric shape and residual stress after this process. Then, the exterior flow field of the glassrun sealing area of a simplified vehicle model was calculated with CFD simulation to obtain the hydrodynamic pressure excitation acting on the outer surface of the sealing strip at different wind speeds, and the results were subsequently validated through wind tunnel test. With Arbitrary Lagrangian-Eulerian (ALE) numerical method, fluid-structure interaction (FSI) was simulated, the morphing mesh and overset mesh techniques were used to achieve FSI boundary motion and effective closure of the wall boundary gap, respectively. In this way, a nonlinear dynamic model of the coupled sealing structure and flow field was comprehensively established. Considering factors such as contact friction model, the forced vibration response and sealing aspiration condition of the sealing strip under actual excitation of time-varying pressure difference were analyzed. The results demonstrate that the contact state between the seal and the side window becomes unstable, when the hydrodynamic pressure fluctuation intensity on the outer surface of the glassrun seal is 34%, and the average pressure difference reaches approximately 1700 Pa. This instability manifests as a significant and persistent fluctuation on the contact area, ultimately leading to aspiration. These findings are of significant importance for optimization of the side window sealing system and precaution of aspiration noise.
Li, HanqiHe, YinzhiZhang, LijunZhang, YongfengYu, WuzhouJiang, ZaixiuBlumrich, ReinhardWiedemann, Jochen
Low density polyurethane foam was first proposed as an alternative to expandable baffles and tapes for sealing vehicle body cavities towards the end of the last century. Despite several inherent advantages for cavity sealing, the high equipment cost of dispensing amongst other reasons, this technology has not spread as widely as expected. With the advent of electric vehicles, there is an increased emphasis on controlling higher frequencies from motors, inverters and other components, and polyurethane foam can be a viable solution by providing more robust sealing. Polyurethane foam sealing is already being employed in the new breed of electric vehicles, but its NVH advantages have not been fully studied or published in literature. Using an existing electric vehicle with conventional expandable baffles & tape sealing measures, a comprehensive evaluation of NVH performance using the closed-cell polyurethane foam solution was conducted. Testing included component level bench test on body-in-white, body-in-white, and full vehicle air leakage tests, vehicle airborne source-to-receiver transfer functions and vehicle on-road performance. The results indicate that closed-cell polyurethane solution clearly improves NVH performance over the traditional sealing solution at the component level (cavity treatment), system level (body-in-white) and full vehicle level. Compared to existing sealing solution, the total vehicle leakage was improved by 20% and airborne noise sensitivity of the vehicle improved by up to 1 dB. This resulted in on-road vehicle NVH performance improvements of approximately 2.4% in the airborne frequency range. With a competitive cost and mass offering, low density polyurethane foam is a formidable alternative to conventional expandable baffles and tapes with clear potential to improve high frequency NVH performance in EVs.
Kavarana, FarokhGuertin, Bill
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