Browse Topic: Elastomers

Items (3,353)
To improve stress-distribution uniformity and reduce wear during polishing, a biomimetic flexible polishing tool was developed by incorporating microstructured surface features inspired by the gastropod shell. A biomimetic flexible polishing tool was first geometrically modeled, and then the tool–workpiece contact was analyzed in the elastic polishing regime using Preston’s material removal equation to elucidate stress transmission and contact deformation mechanisms. An Abaqus finite-element model of the elastic tool–workpiece contact was subsequently established to compute tool and workpiece stress fields and contact-area fraction during polishing. The biomimetic tools were fabricated by curing silicone rubber mixed with carbon nanotubes. Polishing validation was performed on a small CNC platform using quartz glass under the parameters α=15°, ap=2mm, and w=30r/s. Results indicate that the biomimetic tool incorporating gastropod-shell microstructures increases the machining contact area by up to 48.60% relative to a conventional tool, and after t=30 min of polishing the surface roughness Ra decreased from 1.019μm to 76nm. These outcomes demonstrate that the biomimetic microstructured flexible tool effectively improves contact stress uniformity and enhances surface- processing accuracy for quartz glass.
Song, JintaoHui, JizhuangGuo, LeiXu, ChenHei, ZhengqiangZhong, TaiyangWang, JiaweiLiu, Jin
This device belongs to the field of aviation materials technology and discloses a high-efficiency drilling equipment for manufacturing aviation materials, which includes a bottom plate. The top of the bottom plate is provided with a clamping structure and a positioning structure. The clamping structure includes a second moving plate, a third sliding groove, a second bi-directional screw, a fourth screw block, a clamping plate, and a rubber block. This device can hold materials through a clamping structure and effectively and quickly locate and drill holes through a positioning structure. By rotating the first threaded rod, it can drive the first screw block to move the U-shaped column. During the movement of the U-shaped column, it will drive the second threaded rod to move together. By rotating the second threaded rod, it will drive the second screw block to adjust the height of the connecting plate for drilling holes. By rotating the third threaded rod, it will drive the first moving plate to move, which will facilitate the multi-directional movement of the drill bit, improve the efficiency of drilling, avoid multiple position changes, and be beneficial for practical applications and operations.
Li, ZuxianLi, Ling
This study adopts a solvent-free in-situ molding process, using liquid ethylene-propylene-diene monomer (LEPDM) as the base rubber to prepare vacuum sealing materials. The effects of the blending ratio of EPDM/LEPDM on mechanical properties, processing characteristics, physical-mechanical properties, compression characteristics, and vacuum condensable volatiles were investigated. The influence of lamellar intercalated structural fillers on gas permeability was also examined. The results indicate that the addition of LEPDM significantly reduces the Mooney viscosity, improves filler dispersion, and achieves good processability. When the LEPDM blending amount exceeds 20 phr, significant changes occur in mechanical properties, compression modulus, and compression set, which are related to phase transformation. Vacuum pretreatment and vacuum condensable volatile test results show that the traditional plasticizer DOP exhibits high total mass loss (TML) and collected volatile condensable materials (CVCM). However, when LEPDM is partially used to replace EPDM at a blending ratio of 20 phr, TML ≤ 1% and CVCM ≤ 0.1% can be achieved. With the increase in organically modified montmorillonite (OMMT) content, the gas permeability coefficient first decreases and then increases. When the OMMT content is 15 phr, the material exhibits good gas barrier properties
Han, XiaoShi, LeiChen, ZongwenZhang, ZhaoyangCheng, Wei
For the solid-liquid mixing of hydroxy-terminated polybutadiene, which is a high-viscosity fluid with a viscosity of 3.5 Pa · s, and micron-sized silicon dioxide particles, this study employs the CFD-DEM numerical simulation method to analyze the solid-liquid mixing process of the ribbon-type composite impeller (RTC impeller). The stirring performance of the RTC impeller is investigated from perspectives including fluid flow field distribution and particle dispersion mechanism. The research results show that the main circulating flow generated by the RTC impeller generally exhibits a roughly symmetric distribution characteristic, and the flow pattern of the main circulating flow on both sides of the central structure is relatively balanced; however, there is a certain difference in the flow trend of the secondary circulating flow pattern on both sides of the central structure. The main circulating flow provides basic flow power for the secondary circulating flow, while the secondary circulating flow adjusts the local energy distribution through vortex motion. These two flows act synergistically to achieve an efficient solid-liquid mixing process.
Li, RuizhengZhang, YanSun, ZhenxingWu, Qiong
Electric high voltage (HV) cables are commonly used in automotive applications and very prominently in electrified vehicles. These cables are potential flanking transmission paths for structure-borne sound in a broad frequency range and must therefore be included in the NVH design process. Electrical high voltage cables exhibit non-linear mechanical characteristics, when exposed to significant bending the internal geometry of the cable will change and a curvature dependent bending stiffness will result. The electrical cables envisaged in the current publication feature a helically wound stranded aluminium wire core. This conductive core is covered by, in sequence, a silicone rubber insulation, a braided aluminium wire shield with aluminium foil to minimize electromagnetic interference and a silicone rubber outer sheath. An extensive measurement campaign was carried out to dynamically characterize cable specimen of different lengths and cross sections in terms of multi-degree of freedom transfer stiffnesses from 20 to 2000 Hz. In order to investigate possible temperature dependences this dynamic characterisation was carried out for temperatures ranging from -30 until +60 °C. Moreover, additional measurements on bent cable specimen allowed to assess the dependence of the bending stiffness on the cable curvature. It is shown that suitable results can be obtained by modelling the conductive core using an isotropic multi-layer continuum model and by using corrected material characteristics to account for curvature effects. Temperature effects are shown to be negligible within the tested range.
Nijman, EugeneBuchegger, BlasiusBöhler, ElmarZeller, BernhardRejlek, JanFaksa, LukášLukavsky, David
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
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 reduction within the band considered and modal properties remained largely unchanged upto 200 Hz, indicating that the coating did not significantly alter the structural properties. The apparent enigma calls for a detailed study. A brief overview on the results and the plausible reasons are detailed in the paper. Out of the probable causes, the observed vibration reduction can be primarily attributed to the operational damping and mass addition effects of the PC10 coating. These findings highlight an effective and practical approach for mitigating acoustic-induced vibrations in aerospace structures, with direct application to launch vehicle stages and other aerospace hardware where post-fabrication solutions are critically needed.
Avirah, Nohin KPanda, Ajay KumarShaikh, Altafhusen
Submarine-launched missiles with domed nose cones are highly vulnerable to cavitation erosion as they travel at high speed through an underwater launch tube and then into the air from the sea surface. The collapse of vapour cavities crystallizes intense damage on the vehicle surfaces so that the vehicle structure and aerodynamic performance are threatened. In this work, we show the full 3D numerical and analytical analysis of surface protection concepts for the reduction of cavitation damage on such an axisymmetric dome-shaped body. A computational methodology was developed by importing a complex computer-aided design (CAD) model of a dome and the connecting tubular structure into a high-fidelity simulation environment. The geometry was simplified by omitting non-essential details to facilitate the generation of quality mesh for CFD analysis. Simulations have been carried out to analyze the flow field and pressure distribution under two critical stages, at two angles of attack of 0° and 12° and different launch depths. This investigation focuses on a passive mitigation technique that bonds an optimised rubber padding to the dome's exterior surface. The impact forces from collapsing cavitation bubbles are thought to be absorbed and dissipated by the rubber due to its viscoelastic nature, leading to a reduction of the impulsive stress on the substrate. The results show that the controlled introduction of such a compliant material dramatically changes the surface response to cavitation implosions. The suggested rubber padding is demonstrated to be an efficient and practicable means of protecting the surface; thus, the risk of cavitation erosion is diminished considerably, and the service life and reliability of the underwater projectile vehicle can be improved.
Velayudhan, GauthamP S, PremkumarS, Suhail AhmedP, KrishnakumarVasantharaj, C
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
Aerospace and defense systems demand materials capable of maintaining performance under extreme environmental and operational stressors, including wide thermal cycling ranges, exposure to hydrocarbon fuels, vacuum conditions, and repeated mechanical strain. Silicone-based materials have become essential in these environments because they can retain elasticity, stability, and functionality where many traditional materials fail. Silicones are widely used as coatings, adhesives, sealants, and elastomers in aircraft and spacecraft applications. Their chemical structure enables resistance to both high and low temperatures, while also providing durability against solvents and fuels such as jet fuel. In contrast, many conventional elastomers degrade under prolonged thermal exposure or become brittle at cryogenic temperatures.
This specification covers a synthetic rubber in the form of sheet, strip, tubing, extrusions, and molded shapes. This specification should not be used for molded rings, compression seals, O-ring cords, and molded in place gaskets for aeronautical and aerospace applications without complete consideration of the end use prior to the selection this material.
AMS CE Elastomers Committee
Viscoelastic behavior of polymeric materials serves as a critical indicator of their internal structure and chemical composition, offering valuable insights into energy absorption and dissipation mechanisms. This study focuses on the dynamic characterization of polymer foams through both experimental and numerical approaches, aiming to accurately capture their time and frequency dependent mechanical response. Experimental investigations include uniaxial tension and uniaxial compression, which characterize hyperelastic or instantaneous behavior of the material. Stress relaxation tests and Dynamic Mechanical Analysis (DMA) characterize the dependence on time and frequency. A combination of these tests is effectively utilized to create viscoelastic material models that can describe the material response as a function of time and frequency containing a viscous and an elastic part. This paper presents dynamic characterization of polymer foams in finite element simulations. Theoretical background of the numerical model is briefly discussed. The accuracy of the numerical models is validated through a case study, demonstrating the effectiveness of the combined experimental-numerical approach in predicting the mechanical performance of viscoelastic foams in automotive applications.
M, Gokula KrishnanLin, ChunfuSavic, Vesna
The scope of this document is to define a test method for performing the Compression Stress Relaxation (CSR) Test with the Automotive Standard (ASD) or HP CSR Jig using the appropriate test fixtures, configurations, and procedures. This standard defines the equipment needed, guidelines for running the test, and the format for generating the results and analyzing the data.
Committee on Automotive Rubber Specs
This specification covers a standard acrylonitrile butadiene (NBR-H) rubber stock with medium-high acrylonitrile content in the form of molded test slabs.
AMS CE Elastomers Committee
This SAE Recommended Practice provides a system for marking thermoset rubber parts to designate the general type of material from which the part was fabricated.
Committee on Automotive Rubber Specs
AMS3217/7C has been declared “STABILIZED” by SAE AMS Committee AMS CE Elastomers and will no longer be subjected to periodic reviews for currency. Users are responsible for verifying references and continued suitability of technical requirements. Newer technology may exist.
AMS CE Elastomers Committee
Elastomeric materials are essential in advanced automotive engineering for mobility, isolation, damping, fluid transfer (cooling, steering, fuel, and brake), and sealing because of their unique physio mechanical properties. Elastomers are commonly used in both static and dynamic components, such as hoses, mounts, bushes, and tires. Engine emission standards and weight optimization have caused higher temperature exposure conditions for automotive components. The steering system uses special purpose elastomers like Chlorinated Polyethylene that can deteriorate under abnormal conditions during vehicle operation or manufacturing process due to the high temperature exposure. Therefore, it is crucial to understand the causes and consequences of thermal degradation of elastomers. Thermal degradation is a significant phenomenon that changes the physiochemical properties of elastomers, which results in a product not meeting functional requirements. This study investigates the thermal degradation behavior of chlorinated polyethylene (CPE) polymer subjected to accelerated thermal ageing conditions. Comprehensive material analyses were conducted, including FTIR, TGA, DSC and Microscopical study to evaluate chemical, thermal, and morphological changes. Ageing replication experiments were designed to simulate field-induced thermal hardening and surface cracking, aiming to establish correlation between service or process induced failures and lab-based degradation mechanisms. The results show that prolonged thermal exposure leads to dehydrochlorination, crosslinking, and embrittlement, resulting in hardening, crack initiation and propagation. This experimental study provides comprehensive understanding of ageing kinetics and failure modes of CPE materials under thermal stress, supporting more robust material selection and life prediction in high-temperature applications.
Thiruppathi, AnandhiMishra, NitishKrishnamoorthy, Kunju
Sustainability and environmentally friendly business practices are becoming essential. Tyre industries are embracing the green initiatives to reduce its impact on the environment by exploring the eco-friendly strategies. Starting from the ethical raw material sourcing to a creative recycling technique, strategies are widely distributing in every step of tyre manufacturing to disposition. Each stage of a tyre’s life cycle viz. raw material procurement, manufacturing, transportation both upstream and downstream as well as during the end-of-life phases have an emission-saving potential. It is important to reduce emissions at every stage of tyre’s lifecycle. We have recently developed a Sustainable Tyre with 11% less GHG emission through sustainable raw material approach. Bio sourced or bio attributed raw materials like Styrene Butadiene Rubber (SBR), Polybutadiene Rubber (PBR), Rubber process oil (RPO) and Silica along with natural rubber (NR) had been used. Beside the raw materials from bio source, raw materials obtained from end-of-life tire and waste plastic bottles are also used, to manufacture the sustainable tyre. Being a safety item, developed tyres had gone through different testing process to evaluate the performance. Indoor evaluation viz. RRC, endurance, noise & vibration as well as field evaluation exhibits that the tyre made from sustainable materials are ready to roll on the road. In this paper, the journey starting from selection of raw materials to the placing the tyre in the market with indoor and outdoor validation have been summarised.
Bhandary, TirthankarSingha Roy, SumitPaliwal, MukeshDasgupta, SaikatChattopadhyay, DipankarDas, MahuyaMukhopadhyay, Rabindra
In automotive suspension systems, components like bump stoppers and jounce bumpers play critical roles in controlling suspension travel and enhancing ride comfort. Material selection for these components is driven by functional demands and performance criteria. Traditionally, Natural rubber (NR) has traditionally been favored for bump stopper applications due to its excellent vibration absorption, tear resistance, cost-effectiveness, and biodegradability. However, in more demanding environments, it has been largely replaced by microcellular polyurethane (PU) elastomers, which offer superior durability, environmental resistance, and enhanced noise, vibration, and harshness (NVH) performance. This study revisits NR with the goal of re-establishing its viability by enhancing its performance to match or surpass that of PU. Through compound optimization and advanced material processing techniques, significant improvements have been achieved in NR’s mechanical strength, compression set resistance, and environmental durability. Also a convolute bump stopper design was explored to enhance energy absorption and packaging efficiency. Compared to traditional solid profiles, the convoluted geometry provided progressive stiffness characteristics, improved deformation control, and optimized ride comfort under dynamic loading conditions. Traditional NR design and formulation were compared against PU and next-generation NR in terms of Aging Durability Factor, stiffness, fatigue durability, vehicle-level buzz, squeak, and rattle (BSR), as well as ride and handling performance. A comparative assessment of carbon emissions between PU and NR was also conducted to evaluate environmental impact. The result is a next-generation NR formulation that delivers performance comparable to PU while retaining the ecological and economic advantages of natural rubber. This research demonstrates a sustainable pathway toward high-performance elastomeric materials, bridging the gap between conventional and advanced solutions in modern engineering applications.
Murugesan, AnnarajanHingalaje, AbhijeetPerumal, MathavanPawar, Rohit
Hydrogenated nitrile butadiene rubbers (HNBR) and their derivatives have gained significant importance in automotive compressed natural gas (CNG) valve applications. In one of the four-wheelers, CNG valve application, HNBR elastomeric diaphragms are being used for their excellent sealing and pressure regulation properties. The HNBR elastomeric diaphragm was developed to sustain CNG higher pressure However, it was found permanently deformed under lower pressures. In this research work, number of experiments was carried out to find out the primary root cause of diaphragm permanent deformation and to prevent the failure for safe usage of the CNG gas. HNBR diaphragm deformation investigation was carried out using advanced qualitative and quantitative analysis methods such as Soxhlet Extraction Column, Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), Optical Microscopy (OM), Scanning Electron Microscopy (SEM), and Thermogravimetric Analysis (TGA). For this purpose, we have carried out experiments on OK (HNBR diaphragm with higher bar pressure) and field-failed diaphragms (HNBR diaphragm deformed after lower bar CNG pressure). We have found that OK and Field failed diaphragms have different filler concentrations and uneven dispersion and distribution. Also, the crosslinking density of the failed Field diaphragms was observed in declining order in comparison with the OK diaphragms. TGA and SEM analysis revealed the filler concentration and morphology of the diaphragms. The chemical nature and thermal properties have been analysed using FTIR and DSC analysis techniques. The Soxhlation extractions study helped to understand the crosslinking density of OK and field failure diaphragms. Preventive measures have been implemented to mitigate the HNBR diaphragm permanent deformation issue.
Patil, Bhushan GulabNAIKWADI, AMOLMali, ManojTata, Srikanth
This study aimed to develop a thermally conductive TPE mat and assess its performance in comparison to an existing antiskid rubber mat, specifically evaluating its impact on wireless charger efficiency. Moreover, morphological and thermal analyses were conducted to establish a correlation between the material behaviours of the new and current thermally conductive antiskid mats. The process of developing the thermally conductive TPE involved utilizing a two-roll mill followed by compression moulding to achieve a 2D sheet shape. Notably, the thermally conductive mat demonstrated a consistent enhancement in charging efficiency over the conventional antiskid mat. To examine the thermal characteristics, thermal characterization techniques including DSC and TGA were employed for both the existing and newly developed mats. FTIR spectroscopy was also utilized to confirm the presence of organic functional groups within the mat. The morphological analysis of the fillers used to enhance thermal conductivity was conducted through SEM. The resulting insights contributed to understanding the structural changes that contributed to the improved thermal performance. Subsequently, the developed thermally conductive mat sheet was evaluated in the context of wireless charger performance. The findings and implications of these evaluations were thoroughly discussed. In summary, this research successfully developed a thermally conductive TPE mat and highlighted its superior performance in terms of wireless charging efficiency compared to the traditional antiskid mat. Thermal and morphological analyses provided deeper insights into the material properties, while the evaluation of the mat's impact on wireless charger performance demonstrated its practical significance.
Naikwadi, Amol TarachandMali, ManojPatil, BhushanTata, Srikanth
Polymer compounds used in the manufacturing of automotive interiors are traditionally consist of polymer virgin material, elastomers, additives, pigments, fillers. These compounded polymers are prone to the emission of low molecular weight chemicals over a period of usage and exposure to the environment called volatile organic compounds (VOCs) and carbonyl compounds. These released VOCs and carbonyl compounds consist of chemicals like benzene, toluene, xylene, styrene, acetaldehyde, formaldehyde, acrolein etc. Short term or long-term exposure of these chemicals have adverse health effects like nausea, headache, vomiting, cancer, even death of personnel if found beyond the permissible limits. It has been observed that the majority of passenger have the above symptoms whenever travelled using passenger cars within few minutes of boarding and exchange the car cabin air. The study was planned to understand the reasons for the concerns and further resolution. This paper is focused on the identification of parts and material, evaluation against the recommended tests like Odor, Fogging, VOC, and Carbonyl compound emissions and development of materials used inside the car cabin. This study further provides the acceptance limit of VOCs and carbonyl compound emissions inside the passenger vehicle cabin to address the adverse personnel health concern.
Shukla, Sandeep KumarBalaji, K VVaratharajan, Senthilkumaran
The increasing adoption of electric vehicles (EVs) has intensified the demand for advanced elastomeric materials capable of meeting stringent noise, vibration and harshness (NVH) requirements. Unlike internal combustion engine (ICE) vehicles, EVs lack traditional masking noise generated by the powertrain. In the automotive industry, the dynamic stiffness of elastomers in internal combustion engines has traditionally been determined using hydraulic test rigs, with test frequencies limited to a maximum of 1,000 Hz. Measurements above this frequency range have not been possible and are conducted only through computerized FE or CAE calculation models. Electric drive systems, however, generate distinct tonal noise components in the high-frequency range up to 10,000 Hz, which are clearly perceptible even at low sound pressure levels. Consequently, the dynamic stiffness characteristics of elastomers up to 3,000 Hz are critical for optimizing NVH performance in EVs. This study focuses on high-frequency dynamic stiffness testing of automotive elastomers using a specialized high-frequency test rig. According to ISO 10846-1 [1], there are two methods for determining the dynamic stiffness of elastomers: the direct method (part 2) and the indirect method (part 3). This paper presents measurements carried out using the direct method, employing an electrodynamic shaker and applying static preload conditions. The objective is to accurately determine the frequency-dependent dynamic stiffness and damping properties of elastomeric components, such as engine mounts, bushings, and isolators, which play a crucial role in mitigating structure-borne noise and vibrations.
Bohne, ChristianGröne, Michael
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
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
Steering I-shaft with rubber coupling (or hardy disc) is an important part of complete steering system mainly in body on frame (BOF) vehicles. Hardy discs are used to dampen the vibrations that transmit to steering wheel through frame, steering gear and I-shaft. They also support to accommodate the variation between frame and BIW (Body in white) of body on frame vehicles. They are made up of rubber or other polymer composites, which have less torsional stiffness as compared to metals. The overall torsional stiffness of steering system reduces since the hardy disc is used in series in steering system, that impacts on the overall performance of steering system. So, during development of I shafts with different design, stiffness of hardy discs are used to optimize the steering and NVH performance of vehicle. Considering the development time and cost, each design of I-shaft cannot be validated at vehicle level. The torsional and axial force or displacement of hardy disc is measured at vehicle level on different test tracks and block cycles are made that consists of different displacement / force along with frequencies. These block cycles are then used at bench level testing of I-shafts. This paper summarizes the methodologies to measure the force or displacement of I- shaft, converting raw data to useful block cycles and test set up for bench testing of steering I-shaft.
Kabdal, Amit
Tire wear progression is a nonlinear and multi-factor degradation phenomenon that directly influences vehicle safety, handling stability, braking performance, rolling resistance, and fleet operational cost. Global accident investigations indicate that accelerated or undetected tread depletion contributes to nearly 30% of highway tire blowouts, highlighting the limitations of conventional wear indicators such as physical tread wear bars, mileage-based service intervals, and periodic manual inspections. These manual and threshold-based approaches fail to capture dynamic driving loads, compound ageing, pressure imbalance effects, or platform-specific wear behaviours, thereby preventing timely intervention in real-world conditions. This work presents an Indirect Tire Wear Health Monitoring System that employs an advanced Machine Learning + Transfer learning architecture to infer tread wear level and Remaining Useful Life (RUL) without relying on any tire-mounted sensors. The system ingests CAN bus telemetry signals (e.g., wheel torque, longitudinal/lateral accelerations, brake pressure, speed distribution, steering dynamics, thermal exposure) and converts them into high-resolution wear state estimations through a multi-stage feature learning pipeline. A transfer-learning layer enables model domain adaptation across tire brands, rubber compounds, rim sizes, inflation pressure ranges, and axle-loading variations — reducing retraining cost and ensuring cross-platform. The pipeline supports both cloud analytics workloads (fleet health dashboards, risk scoring, and advisory scheduling) and real-time embedded inference on in-vehicle microcontrollers for predictive safety intervention. On-road validation experiments demonstrate that the proposed model maintains high correlation to ground truth tread depth measurements, delivering per-tire wear estimation, non-linear RUL curves (in km and %), progressive wear trend modelling, and dynamic replacement advisory logic. The proposed architecture therefore establishes a scalable, sensor-less predictive maintenance framework suitable for OEM, Tier-1, and fleet-operations deployment.
Imteyaz, ShahmaIqbal, Shoaib
Rubber components are an important part of the suspension system of high-speed trains, and the complex nonlinear characteristics of rubber parts have a significant impact on the vehicle dynamic performance. This paper establishes a nonlinear dynamics model of the liquid composite swivel arm positioning node, which can reflect the dynamic stiffness and dynamic damping characteristics of the rubber components that change nonlinearly with the frequency and amplitude, and also has a fast calculation speed. The vehicle dynamics simulation model considering the longitudinal stiffness nonlinear characteristics of the arm node is established, and the influence of the stiffness nonlinearity of the liquid composite arm positioning node on the dynamic performance of the vehicle, such as straight-line stability and curve passing ability, is studied in depth through numerical simulation.
Cheng, JunqiangYang, ChenLi, LongtaoCong, RilongHu, Tingzhou
Polymer composites with the addition of natural fibers have gained prominence as a sustainable and technically viable alternative to conventional synthetic materials, especially in applications that require a balance between mechanical performance and environmental responsibility. This study evaluated the mechanical behavior of composites produced with plant fibers from banana (Musa sapientum) and sugarcane (Saccharum officinarum L.), both sourced from the northern region of Brazil. The fibers, used in their natural state without chemical treatment, were cut to a uniform length of 5 mm for standardization. The polymer matrix used was unsaturated terephthalic polyester resin, pre-accelerated and catalyzed with methyl ethyl ketone peroxide (MEKP). The molding of test samples was performed manually in silicone molds, according to ASTM D638 specifications, to ensure repeatability and comparability of results. The mechanical tests revealed that the composites made with sugarcane fibers had an average tensile strength of 17.05 (±1.41) MPa, while those with banana fibers reached 28.85 (±0.94) MPa, compared to 26.94 (±4.60) MPa for the pure polymer matrix. These values indicate that the addition of sugarcane fibers resulted in an approximate 36.7% reduction in tensile strength, whereas the use of banana fibers led to an increase of about 7.1% in this property. The results demonstrate the potential of natural fibers added to polymer composites, especially banana fibers, which acted as reinforcement of the matrix, proving to be a technically efficient and environmentally promising alternative for applications in engineering materials.
Santos Borges, LarissaDias, Roberto Yuri CostaBrandao, Leonardo William MacedoMendonca Maia, Pedro VictorSilva de Mendonça, Alian GomesFujiyama, Roberto Tetsuo
From sorting objects in a warehouse to navigating furniture while vacuuming, robots today use sensors, software control systems, and moving parts to perform tasks. The harder the task or more complex the environment, the more cumbersome and expensive the electronic components.
Researchers at the University of California San Diego have developed a soft robotic skin that enables vine robots that are just a few millimeters wide to navigate convoluted paths and fragile environments. To accomplish this, the researchers integrated a very thin layer of actuators made of liquid crystal elastomer at strategic locations in the soft skin. The robot is steered by controlling the pressure inside its body and temperature of the actuators.
This SAE Aerospace Standard (AS) provides dimensions and procedures for a standardized test fixture used to evaluate the static performance of O-rings and other seal types in glands per AS4716 and AS5857.
AMS CE Elastomers Committee
This SAE Aerospace Information Report (AIR) provides a general description of methods for hardness testing of O-rings including factors which affect precision and comparison of results with those obtained in standard tests.
AMS CE Elastomers Committee
This specification covers a high temperature, compression set and fluid resistant fluorocarbon (FKM) rubber in the form of sheet, strip, tubing, extrusions, and molded shapes for aeronautical and aerospace applications.
AMS CE Elastomers Committee
This specification covers a silicone (PVMQ) rubber in the form of sheet, strip, tubing, extrusions, and molded shapes.
AMS CE Elastomers Committee
The research work elaborated the structural integrity of airvent by skipping the assembly level snap fit finite element analysis of knob to reduce computational complexity of air vent knob sliding test post stopper. During assembly, the strain based mechanical breakage prediction of airvent sliding knob snaps is investigated in non-prestressed condition. The research work proposes a FEM based analysis approach to evaluate the mechanical breakage load of airvent knob assembly for accidental sliding load. This process skips the assembly level snap insertion load case along with silicone rubber pad compression which could serve as the prerequisite simulation. This prerequisite simulation is computationally expensive and complex to solve due to polymer plasticity and silicone rubber elastomer hyper-elasticity and moving frictional contacts between parts. If the accidental sliding load case without considering pre-tension on snaps is simulated, the load causing mechanical failure in the FEM based analysis is not correlating with experimental prototype samples breakage force values. The strain at break for composite, polycarbonate (PC) with acrylonitrile-butadiene-styrene (ABS) material used for knobs, is 100%. By considering the lower strain criteria of 5%, the analysis results and experimental testing results in terms of load causing mechanical breakage and breakage zones are co-related. To validate the established breakage strain criteria of 5%, another airvent knob design with same material of knob is considered for study. A good correlation is established between FEM approach and experimental testing. It is concluded from the outcomes of the FEM based analysis that the 5% strain as breakage criteria set for capturing knob strength for accidental sliding load case is efficient. The same process set can be utilized for developing more airvent knobs.
Shah, VirenMiraje, Jitendra
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
Melanoma testing could one day be done at home with a skin patch and test strip with two lines, similar to COVID-19 home tests, according to University of Michigan researchers. Developed with funding from the National Institutes of Health, the new silicone patch with star-shaped microneedles, called the ExoPatch, distinguished melanoma from healthy skin in mice.
In today’s medtech landscape, innovation isn’t just about what a device does — it’s about how reliably and cost-effectively it gets to market. As devices grow smaller, smarter, and more user-centered, materials like liquid silicone rubber (LSR) play a bigger role in enabling performance, comfort, and compliance. From implantables to connected wearables, LSR is helping engineers meet growing design and usability demands. As demand for the material grows, so do the pressures on supply chains, including launch timelines, increased regulatory scrutiny, and rising technical complexity.
The possibility of reducing CO2 emissions through sustainable paraffinic fuels opens opportunities for the continued use of existing infrastructure and combustion systems. At the same time, fuel switching also presents challenges in terms of the materials used. The changing composition of paraffinic fuels and their impact on plastic materials is a frequent topic of discussion. Compared to distillate diesel, neat paraffinic fuels contain almost no aromatics, which are known to cause swelling in plastics, especially elastomers. This literature review aims to examine and summarize studies on the influence of paraffinic fuels compared to distillate diesel on elastomers. On the fuel side, attention will be given to fuels with different total aromatics content and neat paraffinic fuels. In the field of elastomers, materials used for sealing applications and hoses are analyzed in detail. Special attention will be paid to NBR, FKM, and EPDM. The review aims to answer three questions. The first question relates to the influence of aromatic fuel components on elastomers and their swelling behavior. The second question examines the influence of non-aromatic fuels on other mechanical properties of elastomers. The third research question examines the effects of switching between aromatic-free and aromatic-containing fuels. Key findings reveal that elastomers such as NBR, FKM, and EPDM react differently to aromatic and non-aromatic fuels. NBR tends to swell significantly with higher total aromatics content, with volume increases reaching up to 20%. In contrast, FKM shows minimal swelling across the entire total aromatics content range (0–3%), while EPDM exhibits extreme volume changes, up to 200%. The review further highlights the influence of aromatic-free paraffinic fuels on additional mechanical properties of elastomers. FKM remains stable, whereas EPDM experiences significant weakening. Additionally, alternating fuel exposure between aromatic and non-aromatic fuels revealed reversible changes in elastomer properties, especially for NBR and EPDM.
Conen, TobiasHäfele, BenjaminDahlmann, Rainer
Researchers have developed a soft, thin-film auditory brainstem implant (ABI). The device uses micrometer-scale platinum electrodes embedded in silicone, forming a pliable array just a fraction of a millimeter thick. This novel approach enables better tissue contact, potentially preventing off-target nerve activation and reducing side effects.
This specification covers one type of a non-melting, heat-stable silicone compound, for use in high tension electrical connections, ignition systems, and electronics equipment, for application to unpainted mating threaded or non-threaded surfaces, and as a lubricant for components fabricated from elastomers. This compound is effective in the temperature range from -54 °C (-65 °F) to +204 °C (400 °F) for extended periods. This compound is identified by NATO symbol S-736 (see 6.5).
AMS M Aerospace Greases Committee
Brazil produces approximately 40 million tires annually and discards over 450,000 tons within the same period. Improper disposal turns tires into an environmental liability; each unit can take about 600 years to decompose in nature. This can cause environmental damage and contribute to disease proliferation by creating mosquito breeding grounds, including vectors for Dengue, Zika virus, Chikungunya, and Yellow Fever. To mitigate these damages, Block Selantes was founded in 2018. The company utilizes discarded tires to produce automotive sealants that prevent punctures and tire wear. It is the only company globally to use recycled tires as a sustainable raw material for sealants, a process protected by an industrial patent, resulting in a unique product fully compatible with tire rubber. Additionally, using the sealant in automotive applications significantly enhances vehicle operation safety, reduces costs, and improves logistical efficiency. The use of recycled raw materials also reduces CO2 emissions and generates carbon credits for logistics operators. This paper details the tests and results obtained during the technical validation of the sealant when applied to commercial passenger and cargo vehicles.
Cardoso, Diego JardimBarros, Dimitri AugustoCiapparini, Joel VicenteRausch, BrunoBen, Bernardo Sacilotode Gonzaga Paul, DácioFascina, Luiz Henrique
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 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
Vibration control is most important in automotive applications, and generally, rubbers are used to dampen these vibrations due to their inherent nature and low-cost manufacturing methods. Now, to select a rubber material, Shore hardness is considered in engineering applications, but to additionally control the behaviour, we need to understand its static and dynamic stiffness. These values help to determine the vibration isolation obtained by these rubbers. In this paper, we will discuss methods to calculate the static and dynamic stiffness of rubber grommets using experimental methods and FEA modelling. As elastomers have non-linear material properties, various material modelling techniques in FEA are used to capture multiple phenomena like creep, fatigue, and dynamic conditions. Rubber compounding is used in order to improve the physical and chemical properties, which in turn would give desirable linear characteristics. Certain guidelines and thumb rules are used in the rubber industry for different loading conditions to have linear stiffness behaviour. Static and dynamic stiffness values obtained by experimental and FEA modelling are in a variation of below 5%.
Khamkar, Prasad SubhashGaikwad, Vikrant Chandrakant
Helicopter pilots are exposed to a wide range of vibration frequencies, primarily generated by engine and rotor dynamics. These vibrations, particularly within the 0.5–80 Hz range, pose significant risks to pilot health, including musculoskeletal injuries and fatigue. To mitigate these effects, vibration isolators are employed, with passive and active isolation systems offering different advantages. This study investigates the initial design and performance of a novel metal additive manufactured vibration isolator, optimized for placement under the pilot's seat in a rotorcraft simulator. The isolator was designed with key structural parameters including stiffness, coil dimensions, and material properties while maintaining a lightweight and durable form, with a primary goal of validating the additive manufacturing of a metallic isolator. Experimental corroboration was conducted by incorporating modifications to the Gannon Biomechanics Flight Simulator test stand (GBFS), comparing the novel isolator to an elastomeric isolator. Results demonstrate the successful fabrication of the initial additive isolator design. The additive isolator displayed a similar performance to the rubber isolator after being installed in the GBFS, though limitations on the current test rig and sensing configuration did not allow accurate characterization of the transmissibility. This research sets the groundwork for further development of a novel additive isolator and test facility.
Arzalluz, IratiJi, XiaoxuPiovesan, DavideMarr, Conor
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