Gasket Material Research Articles

A new monitoring approach for sustainability assessment of subsurface utilities gasket materials against gasoline and chlorinated solvents: Field evaluation and model development

Once installed, underground concrete pipes with rubber gaskets might be exposed to contaminated soil and groundwater. A pipe material monitoring capsule (PMMC) has been developed to evaluate volatile organic compounds (VOCs) breaking through three types of pipe gaskets; Neoprene, Buna-N, and Viton. The PMMCs were deployed in three contaminated sites: two with gasoline and one with chlorinated solvent (CS). A 3-D field-domain numerical model has been developed for each site to calibrate equivalent hydraulic parameters of each gasket material (ke, D) against benzene and PCE diffusion. The calibrated parameters were then used to compute the concentrations as well as rate of breakthrough of the two study contaminants. A protocol was developed for installing/retrieval of PMMCs to monitor PCE and benzene mass breaking through the gasket material with time. Employing PMMC, benzene concentrations breaking through the Neoprene and Buna-N after 4 months were approximately 70% and 60% respectively of the monitoring wells concentration. The corresponding value for PCE breakthrough after 4 months was 60% for both the Neoprene and Buna-N. Both gasket materials of Neoprene and Buna-N yielded similar performances, including higher rate of contaminant breakthrough compared to Viton. A nonlinear relationship of mass breaking through the gaskets of benzene and PCE with time was discerned from the modeling and field data.

Numerical evaluation of effective compression behaviour of spiral wound gasket under loading and unloading

ABSTRACTGaskets are used as interfacing element between the mating surfaces, to seal the flange joint. The interfacing elements are usually subjected to compression during loading and relaxation during unloading. The unloading behaviour of the gasket material, when subjected to internal fluid pressure, controls the residual deformation in gasket. A methodology is proposed to obtain the homogenised behaviour of heterogenous gasket by volume averaging the response from micromechanical analysis. The response includes both loading and unloading characteristics of the gasket material. Here, the individual constituents’ characteristics in the spiral wound gasket is modelled using their respective elasto-plastic behaviour. But the unloading behaviour is more affected by the plastic properties. Therefore, the anisotropic Hill’s plastic parameters are evaluated by analysing the representative volume element of the gasket under different loading conditions. The compressive behaviour of the spiral wound gasket from homogenisation is compared with the experimental values for both loading and unloading conditions. An improved unloading behaviour is obtained using the proposed methodology.

In Silico Fit Evaluation of Additively Manufactured Face Coverings.

In response to the respiratory protection device shortage during the COVID-19 pandemic, the additive manufacturing (AM) community designed and disseminated numerous AM face masks. Questions regarding the effectiveness of AM masks arose because these masks were often designed with limited (if any) functional performance evaluation. In this study, we present a fit evaluation methodology in which AM face masks are virtually donned on a standard digital headform using finite element-based numerical simulations. We then extract contour plots to visualize the contact patches and gaps and quantify the leakage surface area for each mask frame. We also use the methodology to evaluate the effects of adding a foam gasket and variable face mask sizing, and finally propose a series of best practices. Herein, the methodology is focused only on characterizing the fit of AM mask frames and does not considering filter material or overall performance. We found that AM face masks may provide a sufficiently good fit if the sizing is appropriate and if a sealing gasket material is present to fill the gaps between the mask and face. Without these precautions, the rigid nature of AM materials combined with the wide variation in facial morphology likely results in large gaps and insufficient adaptability to varying user conditions which may render the AM face masks ineffective.

Methodology of Leakage Prediction in Gasketed Flange Joints at Pipeline Deformations.

The paper presents the proposal of a leakage prediction method in flange joints, after pipeline deformation, based on FEM (Finite Element Methods). The stages of developing the design are discussed, and a complex, multi-stage method of applying the loads is presented in detail. Moreover, the gasket material data obtained in experiments were used. The paper also presents the results of calculations on a non-uniform stress distribution in the radial direction of the gasket. In addition, it has been shown that the deflection of the pipeline with a minor displacement causes an increase in the diversification of the circumferential pressure of the gasket, and also has a significant influence on the determination of the actual state of stress to which the gasket is subject. Moreover, it was found that the distribution of contact pressure on the deflection of the pipeline has a significant influence on the level of leakage. The results of tests are compared to the results of the numerical calculations of the stress in bolts. By comparing the bolt tension changes obtained by numerical and experiment analyses, it has been shown that the assumptions made in developing the numerical model are correct.

Influence of B30 palm-based biodiesel blends upon degradation of elastomers

The use of biodiesel could affect the characteristic of elastomers. It may cause swelling degradation of strength and hardness of the elastomers. In this research, the influence of B30 palm-based biodiesel blends upon degradation of elastomers was investigated, especially elastomers used in the industrial gasket or seal materials, including ethylene propylene diene monomer (EPDM) and fluoroelastomer. The tests were carried out by immersing the elastomers in static B30 (30% biodiesel in diesel) at room temperature (27 – 30 oC) for 1007 h. The elastomeric strength was tested physically by measuring the swelling of mass and volume, hardness, and tensile strength at the 71, 167, 671, and 1007 h immersion time. The results show that fluoroelastomer has a more negligible degradation effect than ethylene propylene diene monomer (EPDM).

Realization of parallel experiments in a diamond anvil cell and their application to water-mineral interactions at high-pressure and high-temperature conditions.

Parallel experiments are normally used to compare different chemical systems and conditions simultaneously. In the field of high-pressure experimental science, parallel experiments are hard to realize due to very limited reaction chamber size for the generation of high-pressure conditions, especially in diamond anvil cells (DACs). Multiple holes, instead of a single hole, can be drilled into a gasket (i.e., multihole gasket technique) to realize parallel experiments in a DAC. In this study, we conducted a series of systematic calibration experiments on multihole gasket techniques using statistical methods. Multiple (two or three or four) holes 100 µm in diameter were symmetrically drilled into a gasket by a laser drilling instrument with the help of a coded Python program. The pressure deviations among different holes in a gasket at average pressures below 10GPa are constrained to less than 0.2GPa in all calibration experiments at room temperature. We further checked the influences of the gasket material, hole number, pre-indented gasket thickness, and temperature on the pressure deviations among different holes in a gasket. Finally, we applied the multihole gasket technique in a DAC experiment and compared the solubility of calcite in different chemical environments at the same pressure and temperature conditions. The experimental results showed that the multihole gasket technique could be widely applied to study water-mineral interactions at high-P (<10GPa) and high-T (<700°C) conditions because multiple parallel experiments can be efficiently realized simultaneously.

An FEA-Assisted Decision-Making Framework for PEMFC Gasket Material Selection

Recent research studies on industrial cyber-physical systems (ICPSs) have witnessed vast patronage with emphasis on data utility for improved design, maintenance, and high-level decision making. The design of proton-exchange membrane fuel cells (PEMFC) is geared towards improving performance and extending life cycles. More often, material selection of PEMFC components contributes a major determining factor for efficiency and durability with the seal/gasket quality being one of the most critical components. Finite element analysis (FEA) offers a simulated alternative to real-life stress analysis of components and has been employed on different rubber-like gasket materials for hydrogen fuel cells for determining an optimal strain energy density function using different hyperelastic models following uniaxial tensile testing. The results show that the Mooney–Rivlin, Ogden, and Yeoh models were the most fitting model with the best stress–strain fit following a weighted error evaluation criteria which returned 18.54%, 19.31%, and 21.96% for 25% displacement, and 22.1%, 21.7%, and 21.17% for 40% displacements, respectively. Further empirical analysis using the multi-metric regression technique for compatibility testing (curve similarity) between the hyperelastic model outputs and the tensile data reveal that the Yeoh model is the most consistent as seen in the marginal error difference amidst increasing displacement while the Arruda–Boyce model is most inconsistent as shown in the high error margin as the displacement increases from 25% to 40%. Lastly, a comparative assessment between different rubber-like materials (RLM) was presented and is expected to contribute to improved decision-making and material selection.

Multi-scale nonlinear stress analysis of Nb3Sn superconducting accelerator magnets

A multi-scale nonlinear procedure to analyze the stress in Nb3Sn superconducting accelerator magnets is presented to address one of the most challenging obstacles currently facing the successful development of high-field superconducting magnets—the issue of stress management. The study demonstrates that gasket materials (special nonlinear materials) are capable of modeling the complex nonlinear deformation behavior of insulation layers within the Nb3Sn coil block and that Hill materials (orthotropic materials utilizing the Hill yield criterion) are suitable to enable homogenization of the filamentary regions and the resin-impregnated Nb3Sn Rutherford cables. With the whole magnet under preload, cool-down, and Lorentz forces, the nonlinear behavior of the Nb3Sn coil was simulated, in three orthongonal axes, using the combined properties of the gasket materials (insulation layers) and Hill materials (resin-impreganted cable). The procedure makes very few assumptions with regard to material properties because it incorporates actual measured stress–strain curves in the analysis. The coil was simulated to the level of detail of the insulation layers and resin-impregnated cables. The computed compressive azimuthal stresses of the cables were used to assess stress-induced performance degradation. Through submodeling, the area-weighted average axial strains of the strands were computed and employed to evaluate the strain-induced performance degradation. The overall performance degradation of the Nb3Sn coil was thus obtained, and this information was subsequently used to guide the design of the overall magnet. Besides Nb3Sn magnets, this versatile procedure can also be employed in the design of LTS, HTS, and room temperature magnets or of any structures ultilizing composite materials; specifically, it can be used to manage the stress and strain of HTS fusion magnets.

Effects of composite reinforcing filler, vulcanizing temperature, and pressure on mechanical properties of gasket material for proton exchange membrane fuel cells

AbstractGasket is one of the key components in proton exchange membrane fuel cells (PEMFCs), and the performance of the gasket can directly affect the durability and electrochemical performance of the PEMFCs. In this paper, the silicone rubber material, which is being considered as gasket material for PEMFC, was fabricated with different composite reinforcing fillers at different vulcanizing temperatures under different vulcanizing pressures. Effects of the composite reinforcing fillers (i.e., gas‐phase SiO2and nano‐CaCO3), vulcanizing temperatures, and pressures on mechanical properties of the silicone rubber material were investigated. The tensile, hardness measurement, compression set, and compression stress relaxation experimental results show that the mass ratios of the gas‐phase SiO2to nano‐CaCO3, curing temperatures, and pressures had a significant impact on the mechanical properties of PEMFC gasket materials. It is found that the silicone rubber material cured at a vulcanization temperature of 160 °C and a vulcanization pressure of 10 MPa had good compression mechanical properties compared to the materials cured at the other curing temperatures and curing pressures. Orthogonal test results show that, when mass ratio of the gas‐phase SiO2to nano‐CaCO3was 25:20, the silicone rubber material cured at the curing temperature of 160 °C and under the curing pressure of 10 MPa had good compressive stress relaxation performance in this work.

Analisis Numerik Pengaruh Gasket pada Windshield Pesawat Komuter 19 Penumpang Terhadap Fenomena Bird Strike

Aircraft are currently quite popular transportation, due to its ability to utilize air space as a flight path, so that it can be efficient in mileage. To support the safety of airplane passengers, every component on the aircraft must pass the test. One of them in the aircraft windshields that are prone to collisions with other objects. In accordance with the regulations in the Civil Aviation Safety Regulation (CASR) the windshield must withstand the impact load of a 0,91 kg bird. In this simulation, the material shape of the bird uses the EOS Tabular type. For modeling windshields, frame¸ gaskets and birds use a general method for solid materials, namely the Lagrangian method. Rubber used as gasket material with mooney rivlin for modeling material behavior. the polymethyl methacrylate and aluminum alloy 7075 T6 material is used in the windshield and frame. Numerical modeling is validated using analytical results. The gasket thickness of 2 mm produces the most optimum energy absorption. The use of gaskets on the windshield does not have a significant effect on the windshield because the gasket on average is only able to absorb 5% of the total energy absorbed by all windshield parts. The collision parameter that produces the greatest failure occurs at a speed of 87,5 m/s with -15o angle. The area that is most prone to material failure is in the area of the upper bolt hole.

Improved performance of corrugated metal gaskets in boiler’s piping system through multilayered coating

The corrugated metal gasket is still in the early stages of development. However, gasket contact flanges with a high surface roughness (more than 3.5 µm) leak and require a lot of force to tighten. A nickel or copper-coated corrugated metal gasket was designed. A water pressure test was used to measure leaks, and the results revealed that nickel or copper-covered gaskets performed better. The effect of high temperature has not been explored in this study, which only reveals high pressure. The goal of this study is to use copper and nickel coatings to improve the performance of corrugated metal gaskets. Copper or nickel infiltrates the pipe flange's rough surface, preventing leaking. The purpose of this study is to investigate the performance of a coated corrugated metal gasket in a boiler system, which has high temperature and pressure. Corrugated metal gaskets were formed using a cold forming process. The gasket material was SUS304, which is copper or nickel-plated through electroplating. The gasket was installed in a series of pipes in the boiler that flows water at high temperature and pressure. The water leak was trickling on white paper that had been placed beneath the gasket. Even small water leaks are detected on white paper. The thermal camera can detect vapor leaks. The results of the studies reveal that the coated corrugated metal gasket's performance was improved, as seen by the reduction in leakage. At the highest pressure of 7 bar and the lowest tightening force of 40 kN, neither gasket leaked. This result is different from standard corrugated metal gaskets, where at the same pressure and temperature, steam and water leaks are observed. Both copper and nickel-plating types can be used to coat corrugated metal gaskets made of SUS304.

Flexible conductive gasket based on Eucommia ulmoides gum and carbon fillers

Eucommia ulmoides gum (EUG) is an eco-friendly and biodegradable novel polymer having the characteristics of both rubber and plastic, which shows excellent potential for conductive gasket material. A flexible, lightweight, and biodegradable EUG-based/carbon fillers composite was prepared via the hot pressing. The obtained composite demonstrates the advantageous properties, including preferable mechanical performance, thermal stability, thermal and electrical conductivity. Notably, the electrical conductivity of the nanocomposite exhibits preferable stability under several physical and chemical damages. Moreover, the EP/r3.8-C19.2 film delivers the average electromagnetic interference shielding effectiveness (EMI SE) of 21.2 dB, which is further enhanced by increasing the carbon nanotubes (CNTs) content and film thickness. Considering the increased abuse of non-degradable polymers, this green, degradable, facile, and low-cost strategy opens an alternative route for conductive gaskets, facilitating the practical application of EUG.

Creep and thermal ratcheting characterization of polytetrafluoroethylene-based gasket materials

Characterization of Teflon polymer based gaskets under expedited aging is the objective of this work. Teflon gaskets are exploited frequently as a replacement to asbestos fiber gaskets because of their excellent leak tightness and nonhazardous physical degradation properties. The research focuses profoundly on the adverse influence of temperature and thermal cycles on the creep and cumulative damage phenomenon under compressive load. Virgin and expanded PolyTetraFluoroEthylene (PTFE) are tested under 28 and 41 MPa of gasket stress at different temperatures. Intricate analysis of creep under coalesces of thermal ratcheting and principal stress is achieved through Universal Gasket Rig (UGR). The instigated cumulative damage is distinguishable into upper and lower bound temperature region indicating the escalation and decrease of thickness change during cycling which saturates after 12 thermal cycles for expanded PTFE while no saturation is reached for virgin PTFE in even after 20 thermal cycles. Percentage of thickness reduction at different applied stress is nearly the same for virgin PTFE whereas expanded PTFE shows largest reduction under lower stress. Compressive creep bespeaks the impact of temperature and load, thereby dictating the magnitude of ratcheting damage and contrariwise. Finally, the creep and thermal ratcheting has a proliferating effect on value of the coefficient of thermal expansion for all chosen gaskets. Copyright © 2017 VBRI Press.

Optimization of compounding formulation for the development of high-preformance coating material using waste tire powder for gasket application

Nitrile butadiene rubber latex (NBRL) based gasket materials were extensively used in the past due to their excellent oil resistance, good abrasion resistance, and shock absorption as well as good high-temperature stability. Recently, carbon black has been introduced to further improve the oil absorption properties and thermal performance of the gasket materials which increased the total costing and makes the processing difficult due to the agglomeration of carbon black in NBRL. Thus, in this research, waste tire powder (WTP) was introduced to develop high-performance coating materials as an alternative to carbon black in NBRL gasket material. Optimization of new compounding formulation has been carried out by manipulating the WTP loading and hybrid WTP-carbon black filler loading. The filler loading was selected based on the desired surface texture and coating thickness. The experience was also carried out by varying the WTP, Sulphur, and plasticizer loading. The desired surface texture and thickness of coating materials were developed at WTP loading of 80phr and 90phr. Whereas, the optimum Sulphur loading was achieved at 1phr - 2phr, and plasticizer loading of 10phr and 15phr. From the experiments carried out, the optimum loading of WTP was 90phr which gives a fully contained gasket composite. Furthermore, DOP optimum loading is 15phr which gives a smooth surface appearance. Lastly, Sulphur with 1phr gives a more even surface texture as compared to 2phr loading.

Model Simulation of Creep and Thermal Ratcheting of Engineering Polymers

AbstractIn the present work, the creep response at specific temperatures and stress level of several polymers has been modeled by a viscoelastic model, analyzed in previous works. In particular, the experimental creep results under thermal cycling of polymers used in bolted flange connections, utilized as components of pressure vessel and piping are employed. The analysis is focused on the experimental results for polymeric flange materials like high density polyethylene and three types of gasket materials, namely poly‐tetrafluoroethylene PTFE (expanded e‐ and virgin v‐) and clickable nucleic acid. It has been proved that by the implementation of the model on a simple creep curve at a specific temperature, the model parameters could be evaluated. Hereafter, by imposing a thermal cycling process, two more parameters, associated with thermal ratcheting, could be acquired. It is found that the thermal ratcheting behavior exhibited by the employed materials, could be captured with a good accuracy. Given that the effect of thermal ratcheting on the long‐time performance of polymers in targeted applications is a crucial issue, the research findings in the present work are encouraging for the design of appropriate materials, and the prediction of thermal ratcheting.

Analysis of the gasket geometry for sealing glass lamination autoclaves

Nowadays, autoclaves are widely used for industrial applications such as composite material production, laminated glass production and rubber industry. An autoclave is pressurized and heated up according to its special recipes, which are prepared by considering the technical specifications of the interlayer material and the types and thickness of the glass sheets. During the entire laminated glass production period, the gasket on the autoclave door provides sealing and it must not damage the steady air circulation inside the autoclave. In the present study, the sealing of a glass lamination autoclave was investigated numerically. In order to perform finite-element analysis (FEA), a simplified finite-element model was created by considering both the gaps between the autoclave door and its housing and the geometry of the gasket. In general, hyper-elasticity-based gasket materials were used for glass laminating autoclaves. A Mooney–Rivlin hyper-elastic material model was used for this study. In this study, nine different gasket geometries were designed and finite-element method (FEM) analyses of the gaskets were carried out by using the Ansys Workbench software. FEM analyses were performed at 13 bar operating pressure. The results were compared in terms of deformation of the gaskets and von Mises equivalent stress. The most suitable gasket geometry was determined according to the simulation and FEA results.

Stress distribution and performance of threaded bolts in gasketed flange joints

AbstractThe performance of the flange joint depends on the relaxation of load in bolts. This in turn affects the gasket stress and control of leakage. A finite element model of flange joint with threaded bolt‐nut fastener having zero helix angle is developed and analyzed for stress distribution in the threaded bolt. The stress concentration factor at the thread root region is observed to be non‐uniform along the circumference due to the bending behavior of the bolt in the flange joint. The maximum stress is observed in the first engaged thread. The variation in bolt load due to internal fluid, thermal and external loads are also investigated for both single and twin‐gaskets (two concentric half‐sized single gaskets). The gasket material and gasket configuration are observed to be potential factors causing variation in the distribution of load in the flange joint. In a flange joint subjected to external bending load, the maximum stress concentration in the bolt is observed to be in the first thread, instead of the first engaged thread. Under external bending load, the flange joint loses its structural integrity before the traces of leakage occur in the joint.

Influence of fillers on the properties of under-rail gaskets

Using the criterion of the reduced hydration activity of inorganic materials, the choice of magnetic separation waste as a mineral filler for the production of under-rail gaskets is justified. By the methods of experimental planning, mathematical models were obtained that adequately describe the hardness (Shore A) and the conditional tensile strength of the gasket material, using which the composition of the material was developed that exceeds the physical and technical characteristics of the production composition.

Evolution of hydrogen dissolution and superconductivity in Re-based solid solutions under pressure studied by ab initio calculations

The dissolving of hydrogen (H) into rhenium (Re) is non-negligible in high-pressure experiments involving dense hydrogen and hydrogenous materials, in which rhenium is often used as a gasket material in the high-pressure diamond-anvil cell devices. However, the evolution of hydrogen dissolution into Re and the pressure-induced effects of hydrogen coupling on the superconductivity of metal-based hydrides remain poorly understood experimentally, and theoretical investigations are currently lacking. The present work addresses these issues by applying ab initio calculations for systematically investigating the dissolution of H atoms in Re systems, as well as the electronic properties, lattice dynamics, and electron-phonon coupling (EPC) in the corresponding interstitial Re hydrides. A series of $\mathrm{Re}{\mathrm{H}}_{x}$ compounds with increasing $x$ in the range of 0 to 1 in increments of 0.125 are predicted to be stable at increasing pressures ranging from 1 to 50 GPa. It is found that H atoms generally play the role of impurities in the $\mathrm{Re}{\mathrm{H}}_{x}$ compounds except for $\mathrm{Re}{\mathrm{H}}_{0.5}$ and ReH, where H atoms are integrated into the crystal structure. Moreover, the atomic configuration of the Re host lattice is basically preserved with increasing $x$ and increasing pressure. Further analysis of the superconductive mechanism indicates that an increasing H concentration results in a decreased electronic density of states at the Fermi level and increasing phonon frequencies, which lead to a decrease of EPC \ensuremath{\lambda} and superconducting critical temperature. These findings quantitatively clarify the effects of hydrogen doping on superconductivity in metal-based hydrides, and thereby support the exploration of new types of superconductive hydrides.

The Impact of Plastic pH on Silicone Elastomer Compression Set

&lt;div class="section abstract"&gt;&lt;div class="htmlview paragraph"&gt;Sealing applications in electrified vehicle powertrains present a unique set of boundary conditions when contrasted with typical transmission or internal combustion engine applications, including changes in fluidic exposure, operating pressure, temperature profiles, etc. This novel powertrain environment opens the gasket material spectrum to elastomers uncommon in standard powertrain joints, which allows for more optimized, higher-value sealing solutions. However, this also introduces new risks, including the risk of excessive compression set in silicone elastomers due to acidity in adjacent plastics (which can result from shifting to non-halogenated flame retardants from halogenated flame retardants). To understand this phenomenon, compression set testing was conducted with plastic resins ranging from pH = 3.4 to pH = 7.3 and three high-consistency rubber (HCR) silicone elastomers. For each silicone, compression set was plotted linearly against concentration of hydrogen ions ([H+]) in the plastic and plotted exponentially against plastic pH. This produced a regression model relating compression set in the elastomer to acidity of the adjacent plastic. Then, a threshold pH value - after which the plastic begins to significantly increase compression set in the silicone - was determined by overlaying silicone-only compression set results with the silicone + plastic regression model. The resulting threshold value given the associated conditioning was a pH of 4.5 for all three silicone samples tested, indicating that a plastic resin accelerates compression set in the neighboring silicone if the plastic has a pH ≤ 4.5. Studies into the impact of (1) plastic sample form factor (raw material pellets, colorized material pellets, or molded plastic sheets) and (2) time on plastic pH were evaluated; both showed no statistical impact on pH measurements. Overall, this effect is believed to be due to acid-induced cleavage of the siloxane bond, which causes depolymerization in the silicone by breaking the backbone chain, thereby resulting in gasket compression set.&lt;/div&gt;&lt;/div&gt;