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Статті в журналах з теми "Elastomers Deterioration"
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Gotoh, Hiroaki, Chang Liu, Abu Bin Imran, Mitsuo Hara, Takahiro Seki, Koichi Mayumi, Kohzo Ito, and Yukikazu Takeoka. "Optically transparent, high-toughness elastomer using a polyrotaxane cross-linker as a molecular pulley." Science Advances 4, no. 10 (October 2018): eaat7629. http://dx.doi.org/10.1126/sciadv.aat7629.
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An elastomer is a three-dimensional network with a cross-linked polymer chain that undergoes large deformation with a small external force and returns to its original state when the external force is removed. Because of this hyperelasticity, elastomers are regarded as one of the best candidates for the matrix material of soft robots. However, the comprehensive performance required of matrix materials is a special challenge because improvement of some matrix properties often causes the deterioration of others. For example, an improvement in toughness can be realized by adding a large amount of filler to an elastomer, but to the impairment of optical transparency. Therefore, to produce an elastomer exhibiting optimum properties suitable for the desired purpose, very elaborate, complicated materials are often devised. Here, we have succeeded in creating an optically transparent, easily fabricated elastomer with good extensibility and high toughness by using a polyrotaxane (PR) composed of cyclic molecules and a linear polymer as a cross-linking agent. In general, elastomers having conventional cross-linked structures are susceptible to breakage as a result of loss of extensibility at high cross-linking density. We found that the toughness of the transparent elastomer prepared using the PR cross-linking agent is enhanced along with its Young’s modulus as cross-linking density is increased.
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Furukawa, M., and K. Wakiyama. "Deterioration of novel polyesterurethane elastomers in outdoor exposure." Polymer Degradation and Stability 65, no. 1 (July 1999): 15–24. http://dx.doi.org/10.1016/s0141-3910(98)00209-2.
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Choi, I. S., C. M. Roland, and L. C. Bissonnette. "An Elastomeric Ejection System." Rubber Chemistry and Technology 67, no. 5 (November 1, 1994): 892–903. http://dx.doi.org/10.5254/1.3538720.
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Abstract The ability of elastomers to store large quantities of energy, which can subsequently be recovered very quickly, makes them attractive materials for propulsion devices. Recently the U.S. Navy has developed a torpedo ejection system based on an elastomeric mechanical capacitor. The criteria governing selection of a material for this application include high elastic energy, sufficient fatigue life, minimal creep, and resistance to deterioration by seawater. This paper describes various approaches to obtaining these material properties.
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Toczek, Klaudia, Magdalena Lipińska, and Joanna Pietrasik. "Smart TPE Materials Based on Recycled Rubber Shred." Materials 14, no. 21 (October 20, 2021): 6237. http://dx.doi.org/10.3390/ma14216237.
Повний текст джерелаАнотація:
Thermo-responsive shape memory materials were developed based on recycled ethylene-propylene-diene (EPDM) rubber shred and thermoplastic elastomers (TPE). Ethylene-1-octene TPEs (Engage 8180, 8411, 8452) with varying degrees of crystallinity and Mooney viscosity were used to prepare the composite materials. To avoid the deterioration of static mechanical properties after mixing recycled EPDM rubber shred (RS) with thermoplastic elastomers, they were partially cured using dicumyl peroxide. The peroxide curing was the most effective for a rubber shred/Engage 8180 blend, where the highest cure rate index (CRI), 1.88 dNm⋅min−1, was observed. The curing caused an approximately 4-fold increase of tensile strength (TS) values for EPDM rubber shred/thermoplastic elastomer blend to the level acceptable for the rubber industry compared with an uncured blend. The incorporation of EPDM rubber shred changed thermoplastic elastomers’ viscoelastic behavior, increasing the values of storage (G′) and loss (G″) modulus. The lowest viscosity of molten Engage 8411 during mixing led to higher compatibility of rubber shred RS/8411 blend, as confirmed by analysis of Cole-Cole plots and the blend morphology. All rubber shred RS/TPE blends showed the shape memory behavior. For the RS/Engage 8452 blend, the highest shape fixity (F) value (94%) was observed, while the shape recovery (RR) was 87%. Studies confirmed that the intelligent materials with shape memory effect could be obtained via selectively chosen thermoplastic elastomers; ethylene-1-octene as a binder for recycled EPDM. Prepared recycled TPE/rubber shred blends can be successfully reused due to their viscoelastic and mechanical properties. Therefore, such a concept can be potentially interesting for the rubber industry.
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Gunatillake, Pathiraja A., Darren J. Martin, Gordon F. Meijs, Simon J. McCarthy, and Raju Adhikari. "Designing Biostable Polyurethane Elastomers for Biomedical Implants." Australian Journal of Chemistry 56, no. 6 (2003): 545. http://dx.doi.org/10.1071/ch02168.
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The chemical structure, synthesis, morphology, and properties of polyurethane elastomers are briefly discussed. The current understanding of the effect of chemical structure and the associated morphology on the stability of polyurethanes in the biological environments is reviewed. The degradation of conventional polyurethanes appears as surface or deep cracking, stiffening, and deterioration of mechanical properties, such as flex-fatigue resistance. Polyester and poly(tetramethylene oxide) based polyurethanes degrade by hydrolytic and oxidative degradation of ester and ether functional groups, respectively. The recent approaches to develop polyurethanes with improved long-term biostability are based on developing novel polyether, hydrocarbon, polycarbonate, and siloxane macrodiols to replace degradation-prone polyester and polyether macrodiols in polyurethane formulations. The new approaches are discussed with respect to synthesis, properties and biostability based on reported in vivo studies. Among the newly developed materials, siloxane-based polyurethanes have exhibited excellent biostability and are expected to find many applications in biomedical implants.
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Senichev, V. Yu, and E. V. Pogorel’tsev. "Abrasive resistance of polyetherurethane ureas." Journal of Physics: Conference Series 2094, no. 4 (November 1, 2021): 042077. http://dx.doi.org/10.1088/1742-6596/2094/4/042077.
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Abstract The relationship between the structure of the polymer chains and the abrasion resistance of segmented polyurethane ureas based on polyoxytetramethylene oligoether was studied. Experimental data were obtained for systems with the hard segments content above 39%. It was found that the function of the volumetric wear of polyurethane-urea samples on the content of hard segments had an extremum; at high contents of these segments (more than 35%), a further increase in this content lead to a deterioration in the abrasion resistance. The reasons for this effect can be associated with a sharp deterioration in the strength and strain properties of the studied elastomers when additional amounts of diisocyanate are introduced into the system, which can lead to the formation of excessive interchain bonds.
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Diekmann, Astrid, Marvin Christopher Vincenzo Omelan, Ulrich Giese, and Viktor Rose. "CARBON NANOHORN–BASED NBR HYBRID NANOCOMPOSITES." Rubber Chemistry and Technology 93, no. 4 (October 1, 2020): 615–32. http://dx.doi.org/10.5254/rct.20.79958.
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ABSTRACT Carbon nanohorn (CNH)–filled elastomer hybrid nanocomposites were prepared based on NBR. Three different CNH types were analyzed, each featuring various characteristics such as aggregate structure, specific surface area, surface energy distribution, and electrical conductivity and resulting in different potentials regarding the properties of the developed elastomers. For the CNH types, a high tendency of agglomeration was observed in the pristine state, indicating the need for an effective strategy to break up the agglomerates during the mixing or the compounding procedure to realize their incorporation and sufficient dispersion in a polymer matrix. In addition to the melt mixing technology by means of an internal lab mixer, a discontinuous static and a continuous dynamic latex compounding process were used. Carbon nanotubes and a highly conductive carbon black (Printex) were used as hybrid fillers in the compounds mixed by melt mixing, whereas two different types of carbon black (Printex and Derussol) were also incorporated in the latex experiments. Hybrid nanocomposites with low content of CNHs (≤1 wt%) show an improvement in dynamic-mechanic and physical properties due to distinctive polymer–filler interactions. Dealing with higher amounts of CNHs leads to filler reagglomeration, resulting in deterioration of the elastomer properties. For the electric conductivity assessment, addition of CNH indicates no synergistic effects and no significant increase of the hybrid compounds, which is demonstrated in dielectric measurements, although pristine CNHs are conductive themselves. Elastomer compounds processed via the latex method show enhanced material performance by using the continuous dynamic latex compounding, which is mainly attributed to the dispersion of the hybrid filler.
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Hu, Hang, Dongsheng Li, and Weijun Zhu. "Piezoelectric composites from sandwiched polydimethylsiloxane sponges." Journal of Applied Physics 132, no. 18 (November 14, 2022): 184901. http://dx.doi.org/10.1063/5.0111435.
Повний текст джерелаАнотація:
A novel elastomer-based composite material with enhanced piezoelectric performances is proposed in this paper, which is composed of the top and bottom polytetrafluoroethylene (PTFE) solid films with the middle PTFE nanoparticle–polydimethylsiloxane (PDMS) sponge layer. To enhance the charge retention capability of elastomers, PTFE nanoparticles are introduced to form PTFE–PDMS interfaces, which can trap charges with longevity. Besides, PTFE solid films take on the role of the charge blocking layers to further improve the piezoelectric performances. As a result, the PTFE–PDMS sandwich structure shows the advantages of remarkable sensitivity (1053 pC/N), high stability, and flexibility. After a 6 h of annealing treatment at the temperature of 100 °C, no significant deterioration of the piezoelectric properties can be observed, which reveals the great thermal stability of the sandwich structure. In addition, the sandwich structure can be immersed in water for 24 h without any loss of piezoelectric activity. Finally, the experiment of lighting one LED by hand pressing successfully demonstrates that the sandwich structure has good applicability in the field of energy harvesting. Considering the excellent electrical and mechanical features, the PTFE–PDMS sandwich structure has promising applications in sensing, energy harvesting, and actuation.
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Huang, Xiaoyu, Jinghui Zhao, Yichun Wang, Yuchao Ke, and Zixi Wang. "Study on a New Static Sealing Method and Sealing Performance Evaluation Model for PEMFC." World Electric Vehicle Journal 12, no. 4 (November 11, 2021): 237. http://dx.doi.org/10.3390/wevj12040237.
Повний текст джерелаАнотація:
The long-term stability and durability of seals are critical for various instruments and types of equipment. For static sealing, an important sealing state, there are currently two representative sealing methods, namely, pre-compressing static sealing and adhesive static sealing. In this paper, the characteristics and shortcomings of these sealing methods are summarized. At present, some static sealing requirements are urgent and difficult. For example, the deterioration of the sealing performance is an important factor which limits the service life of proton exchange membrane fuel cells and redox flow batteries. Therefore, a new method of static sealing whose sealing materials are rubber elastomers is proposed, named alterable static sealing. Then, its sealing processes are proposed. Furthermore, the actual contact area ratio r is used as the standard for sealability. Based on the mathematical model of pre-compressing static sealing, the influence of interface bonding was considered, and the mathematical model of alterable static sealing was established. Moreover, the compensatory effect of alterable static sealing on the static sealing capacity of rubber elastomers was proved.
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Lattimer, Robert P., Robert A. Kinsey, Robert W. Layer, and C. K. Rhee. "The Mechanism of Phenolic Resin Vulcanization of Unsaturated Elastomers." Rubber Chemistry and Technology 62, no. 1 (March 1, 1989): 107–23. http://dx.doi.org/10.5254/1.3536228.
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Abstract It is well known that during the sulfur curing of unsaturated rubbers, two competing reactions occur: (a) crosslinking or vulcanization, and (b) reversion or devulcanization. In the case of butyl rubber, these two competing reactions have been summarized in earlier reports. Tire curing bag (bladder) compounds are usually made of butyl rubber (IIR), a copolymer of isobutene and isoprene, with typically 1–5% of the diene monomer. Curing bags were originally manufactured using sulfur cures. The high temperatures (140–180°C) employed in tire curing caused reversion, however, and these bladders had very short service lives. The deterioration of the IIR bladders was evidenced by a gradual softening of the surface. A major technical advancement for increasing the service life of curing bladders was the development of phenol/formaldehyde (resole) resins for vulcanizing IIR. These resins can give IIR cures with very thermally stable crosslinks. The vulcanizates are essentially immune to reversion, even at the high use temperatures of tire curing operations. The basic curing resins used are generally 2,6-dihydroxymethyl-4-alkylphenols 1 or their condensation polymers 2 (Scheme 1). These materials are produced via the base-catalyzed reaction of the p-substituted phenol with formaldehyde. R is typically methyl, t-butyl, or t-octyl in commercial resins. The use of a blocking substituent in the para position maximizes the formation of o-hydroxymethyl groups. R′ is either methylene (—CH2—) or dibenzylether (—CH2—O—CH2—), depending on the conditions of the resin synthesis or the cure.
Дисертації з теми "Elastomers Deterioration"
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Noronha, Fabio. "Desenvolvimento de requisitos de desempenho para elastomeros de isoladores da rede de energia eletrica." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/267098.
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Orientadores: Lucia Helena Innocentini Mei, Joceli Maria Giacomini AngeliniDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
Made available in DSpace on 2018-08-15T13:39:32Z (GMT). No. of bitstreams: 1 Noronha_Fabio_M.pdf: 6615415 bytes, checksum: f72688fb0000126501c64a7267950cb0 (MD5) Previous issue date: 2010
Resumo: Atualmente, os materiais utilizados como isoladores elétricos vêm sendo substituídos por materiais poliméricos por apresentarem vantagens em relação aos isoladores cerâmicos. Dentre estas vantagens, podem-se citar maior desempenho, melhor resistência ao vandalismo e menor peso. O objetivo desta dissertação foi o estabelecimento de desenvolver requisitos de desempenho para os Isoladores Poliméricos (EPDM- Monômero Dieno/Etileno/Propileno e Silicone) usados na rede elétrica, através de resultados obtidos em ensaios de envelhecimento natural e artificial, tendo como enfoque as linhas de transmissão de 69 kV e 138 kV. Foi realizado um estudo do estado da arte em Isoladores Poliméricos e do estado atual de aplicação e desempenho dos mesmos em campo. Estudos experimentais foram desenvolvidos em produtos retirados de campo e produtos novos, envelhecidos artificialmente em laboratório, segundo metodologias aplicáveis a polímeros. Em paralelo foram estudadas mantas elastoméricas de Silicone e EPDM para elaboração de critérios comparativos. Através dos resultados obtidos, foram sugeridos alguns requisitos de desempenho que poderão ser utilizados em especificações dos mesmos. Nesta dissertação, são apresentados, principalmente, estes resultados obtidos por meio das técnicas de ensaio de Tensões Elétricas, Rugosidade, Densidade, Dureza, FTIR-Infravermelho com Transformada de Fourier, DSC-Calorimetria Exploratória, DMTA-Análise Térmica Dinâmico Mecânica e Resistência à Tração. Os resultados obtidos mostraram a importância de controle da rugosidade bem como da necessidade de aditivação do polímero com sistema de termo e foto estabilização
Abstract: Currently, the materials used as electrical insulators are being replaced by polymeric materials have advantages as compared to ceramic insulators. Among these advantages, we can cite higher performance, better resistance to vandalism and lower weight. The objective of this thesis was the establishment of developing performance requirements for Polymeric Insulators (EPDM monomer diene / ethylene / propylene and Silicone) used in power systems, through results from trials of natural and artificial aging, focusing on the lines transmission of 69 kV and 138 kV. We conducted a study of the state of the art in Polymeric Insulators and current state of implementation and performance of the same field. Experimental studies have been developed into products removed from the field and new, artificially aged in the laboratory, according to the methods applied to polymers. Were studied in parallel webs of silicone elastomer and EPDM for developing benchmarks. Through the results, suggested some performance requirements that could be used in the same specifications. In this thesis, are presented, mainly, these results obtained by the techniques of test voltages, roughness, density, hardness, FTIR-Fourier Transform Infrared, Scanning Calorimetry-DSC, DMTA Dynamic-Mechanical Thermal Analysis and Tensile Strength . The results showed the importance of controlling the roughness and the need for additives with the polymer system and picture stabilization term
Mestrado
Ciencia e Tecnologia de Materiais
Mestre em Engenharia Química
Книги з теми "Elastomers Deterioration"
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H, Yasuda, and American Chemical Society Meeting, eds. Plasma polymerization and plasma interactions with polymeric materials: Proceedings of the Symposium on Plasma Polymerization and Plasma Interactions with Polymeric Materials, held at the ACS 199th National Meeting in Boston, Massachusetts, April 1990. New York, NY: Wiley, 1990.
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Wright, David. Failure of Plastics and Rubber Products: Causes, Effects and Case Studies Involving Degradation. Rapra Technology, 2001.
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Weathering of Plastics: Testing to Mirror Real Life Performance (Plastics & Elastomers). Plastics Design Library, 2000.
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McKeen, Laurence W. Effect of UV Light and Weather on Plastics and Elastomers. Elsevier Science & Technology Books, 2019.
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McKeen, Laurence W. Effect of UV Light and Weather on Plastics and Elastomers. Elsevier Science & Technology Books, 2013.
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McKeen, Laurence W. Effect of UV Light and Weather on Plastics and Elastomers. Elsevier Science & Technology Books, 2019.
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McKeen, Laurence W. The Effect of UV Light and Weather on Plastics and Elastomers. William Andrew, 2013.
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Scheirs, John. Compositional and Failure Analysis of Polymers: A Practical Approach. John Wiley & Sons, 2000.
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Compositional and Failure Analysis of Polymers: A Practical Approach. Wiley, 2000.
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Library, Plastics Design, ed. The effect of UV light and weather on plastics and elastomers. Morris, NY: Plastics Design Library, 1994.
Знайти повний текст джерелаТези доповідей конференцій з теми "Elastomers Deterioration"
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Qamar, S. Z., T. Pervez, M. van de Velden, and F. J. Sanchez. "Design and Fabrication of Test Facility for Longevity Testing of Elastomer Seals." In ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-93145.
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The oil and gas sector has witnessed a marked inclination worldwide towards enhanced oil recovery (EOR) in recent years due to diminishing easy oil in many fields. One of the more popular EOR strategies is the workover method of converting existing weak horizontal producers to maximum reservoir contact (MRC) wells, or dead vertical wells to single horizontal producers or power water injectors. This attempt at maximum well productivity and total oil recovery is based on installation of downhole smart systems to control flow from each lateral. Expandable liners and swelling elastomers are the key drivers enabling this type of zonal isolation. Enhancement and maximization of hydrocarbon recovery is also being attempted through intelligent and multilateral wells. These well systems cannot succeed without proper zonal isolation and compartmentalization of the reservoir. Compared to conventional methods, swelling elastomer packers maintain good zonal isolation in even the most complex environments, yielding major savings in rig time and cost. As yet, no data is available from designers or manufacturers about the durability or service life of swell packers under actual well conditions. A full-scale rig has therefore been designed and fabricated at the Sultan Qaboos University (SQU), in collaboration with a regional petroleum development company, for longevity testing of water-swelling and oil-swelling elastomers. The test battery includes packers made from different swelling elastomer materials, exposed to actual crude oil or water of different salinities, maintained at different temperatures, and subjected to high pressure. Different conceptual designs of the test setup (for longevity testing over a 5 year period) were developed and later evaluated. Detail design of the best concept was carried out and assessed for reliability, manufacturability, assemblability, etc. Salient features of the final design include thermal systems for selected packers, able to continuously maintain temperature over the 5-year period; recirculation system to maintain the desired salinity in some packers; elaborate system for measurement and observation of upstream and downstream temperature and pressure in all tubes; a system for pressurizing the tubes (to 1000 psi) once the elastomers have swelled and sealed. Daily log of readings have been maintained over the last few months. Several months of testing has shown that packers exposed to low salinity and higher temperatures have sealed earlier, and water-swelling elastomers have sealed faster than oil-swelling ones. Three units have not sealed yet, one tube has desealed after initial sealing, one packer has shown seal failure after pressurizing, and two units are exhibiting good sealing under high pressure. Most of these results are in line with material behavior of swelling elastomers observed in earlier laboratory tests. The whole test battery will be monitored over five years, reporting seal temperatures, pressures, seal deterioration or failure, etc. This study can provide direct feedback to field engineers about the lasting capability of different elastomer types under various actual field conditions. This not-as-yet-available information will be valuable in proper selection of swell packers, and may also help in improvement of packer design.
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Akhtar, Maaz, Sayyad Zahid Qamar, Tasneem Pervez, and Farooq Khalfan Al-Jahwari. "FEM Simulation of Swelling Elastomer Seals in Downhole Applications." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-64312.
Повний текст джерелаАнотація:
Petroleum exploration and development industry is witnessing a rapid growth in the use of swelling elastomers. They are being used in new applications aimed at enhanced oil recovery through slimming of well design, zonal isolation, water shutoff, etc. Initially developed as a problem-solving strategy (for repair of damaged or deteriorating wells), swelling elastomers are now targeting major savings in cost and time through reduction in borehole diameter, reduced casing clearance, cementless completions, etc. Due to material and geometric nonlinearity, modeling and simulation of swelling elastomer applications becomes quite complex. In this work, finite element simulation has been carried out to study swelling elastomer seal performance in downhole petroleum applications using the software ABAQUS. A hyperelastic model (that most closely resembles swelling elastomer behavior) is used for simulation of seal behavior. A series of experiments have been designed and performed to determine necessary material properties of a water-swelling elastomer as it gradually swells when exposed to saline water of two different concentrations at 50°C (to emulate field conditions of medium-depth oil wells). A large number of simulations are carried out to investigate sealing behavior against water salinity and swelling time. Sealing pressure at the contact surface between elastomer and formation (or outer casing) is studied for variations in seal length, seal thickness, compression ratio, water salinity, and swelling period. Results show that seal contact pressure increases with amount of swelling, seal length, and compression ratio; higher salinity environment results in lower sealing pressure; and more contact pressure is generated in the case of rock formation as compared to steel outer casing.
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Nakano, Mitsuyuki, Haruko Sasaki, and Harumi Ono. "Radiation Resistance of Rubber Compound for Gasket." In ASME 2011 Small Modular Reactors Symposium. ASMEDC, 2011. http://dx.doi.org/10.1115/smr2011-6567.
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Seals of small and medium modular reactors are considered as not important components compared with seals for the large modular reactors which are current-generation plants. Leakage of seals has been a safety concern, however seal maintenance and replacement are costly and time consuming for the current-generation plants. Therefore, integral designs of small and medium modular reactors eliminate the need for seals. However it is impossible to eliminate seals completely from the detail design and equipments. Seals consisting of organic materials are estimated as serious damaged components at design basis accident (DBA). Especially it is no exaggeration to say that rubber gaskets are weakest gasket at DBA. In the point of view we must know about behavior of rubber deterioration under condition at DBA. It is very important to select rubber compound from a viewpoint of not only adequate rubber that has characteristic required for each specification but also consideration about rubber deterioration under condition at normal plant operation and DBA. However rubber for gasket has not been selected based on precise studies with enough data concerned about the rubber deterioration because there have been less studies in the world. From compression set test, swelling test, and Fourier transform infrared spectroscopy (FT-IR) analysis, it has been indicated that chemical structure of both Ethylene propylene diene monomer rubber (EPDM) and Silicone rubber might be broken by radiation, and crosslinking of elastomer by radiation might progress at the same time. In fact, EPDM compounds have good results of compression set after radiation exposure and Silicone rubber does not have good results. It had been predicted that breakage and crosslinking of elastomer chemical structure caused by radiation would have been more serious on Silicone rubber. On the other hand, it has been estimated that breakage of chemical structure of Fluoro-rubber is more influenced by crosslinking of elastomer by radiation, than influence by low molecular elastomer caused by deterioration have been generated. From these results it is considered that Fluoro-rubber is weak against radiation compared to another elastomer. If Fluoro-rubber must be chosen because of its high thermal resistance for example, a radiation condition of environment should be considered seriously. Unfortunately we could not find significant correlation between compression set and general properties. However results of elongation at breakage indicates possibility of relationship to compression set.
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Ishihana, Kenta, Osamu Furuya, Kengo Goda, and Shohei Omata. "Study on Laminated Type Base Isolation Device Using Urethane Erastomer for Practical Application." In ASME 2015 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/pvp2015-45426.
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Base isolation system will be aggressively applied to not only architectural and civil structures but also various structures, because the effectiveness on seismic safety had been demonstrated again in the Great East Japan Earthquake. In this study, the research and development of laminated type base isolation device using urethane elastomer has been carried out to upgrade a seismic safety for various structures. The fundamental characteristics have been investigated from several loading test by using various experimental devices, and the design formula for the stiffness and equivalent damping coefficient is formulated as an approximate expression of mechanical characteristics until now. Moreover, the experimental examination for aged deterioration in the urethane material has been continuously carried out. This paper summarizes the mechanical characteristics based on the loading test up to 500% shear strain using experimental specimen with 100×100 mm cross-sectional shape, base isolation effect from time response analysis using nonlinear element model of urethane elastomer and the accelerated aging test for verifying the aging of practical use.
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Goda, Kengo, Osamu Furuya, Kohei Imamura, and Kenta Ishihana. "Laminated Type Isolation Device for Light Weight Structure Using Urethane Elastomer." In ASME 2017 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/pvp2017-66167.
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At the present, base isolation system has been recognized by general earthquake resistant technique since the Great Hanshin Earthquake 1995. The seismic isolation will be aggressively applied to not only architectural and civil structures but also various structures, because the effectiveness on seismic safety had been demonstrated again in the Great East Japan Earthquake. In generally, although the base isolation system is divided into laminated rubber bearing type and friction sliding bearing type. In the case of former type, shape factor, maximum or minimum outer shapes and so on are restricted by the material characteristics in visco-elastic material. In general, the isolation structure is used in high damping rubber. However, we pay attention to base isolation using urethane elastomer. Urethane elastomer has excellent elasticity, mechanical strength, abrasion resistance, weather resistance, oil resistance, impact resistance the absorbent, anti-vibration and excellent low-temperature properties. Furthermore, it is possible to impart various characteristics by a combination of isocyanate and polyol and chain extender, requires no large-scale apparatus, it has the advantage molecular design is easy. In previous study, the research and development of laminated type base isolation device using urethane elastomer was carried out to upgrade a seismic safety for various structures. The fundamental characteristics was investigated from several loading test by using various experimental devices, and the design formula for the stiffness and equivalent damping coefficient is formulated as an approximate expression of mechanical characteristics until now. It was confirmed that urethane elastomer is not hardening up to 500% shear strain. Moreover, the experimental examination for aged deterioration in the urethane material has been continuously carried out. As the results, it was confirmed that the laminated type seismic isolation device using urethane elastomer is possible to develop as a practicable device from the stable mechanical properties as considering in design step. In this study, the small-scale laminated type base isolation device using urethane elastomer is advanced to the direction of further technical upgrading and of scale down for light-weight structure as a sever rack. The first stage, basic properties of the urethane elastomer has been investigated by loading test. Furthermore, the design equation is created by loading test using urethane elastomer. The validity of the design equation has been confirmed. The second stage, the compression creep test with laminated type base isolation device has been investigated to confirm an effect on light-weight mechanical devices.
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Ishihana, Kenta, Osamu Furuya, Kengo Goda, and Shohei Omata. "Study on Small-Scale Laminated Type Base Isolation Device Using Urethane Elastomer for Practical Application." In ASME 2016 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/pvp2016-63992.
Повний текст джерелаАнотація:
At the present, base isolation system has been recognized by general earthquake resistant technique since the Great Hanshin Earthquake 1995. The seismic isolation will be aggressively applied to not only architectural and civil structures but also various structures, because the effectiveness on seismic safety had been demonstrated again in the Great East Japan Earthquake. In generally, although the base isolation system is divided into laminated rubber bearing type and friction sliding bearing type. In the case of former type, shape factor, maximum or minimum outer shapes and so on are restricted by the material characteristics in visco-elastic material. In previous study, the research and development of laminated type base isolation device using urethane elastomer was carried out to upgrade a seismic safety for various structures. The fundamental characteristics was investigated from several loading test by using various experimental devices, and the design formula for the stiffness and equivalent damping coefficient is formulated as an approximate expression of mechanical characteristics until now. The mechanical characteristics based on the loading test up to 500% shear strain using experimental specimen with 100 × 100 mm cross-sectional shape. It was confirmed that urethane elastomer is not hardening up to 500% shear strain. Moreover, the experimental examination for aged deterioration in the urethane material has been continuously carried out. As the results, it was confirmed that the laminated type seismic isolation device using urethane elastomer is possible to develop as a practicable device from the stable mechanical properties as considering in design step. In this study, the small-scale laminated type base isolation device using urethane elastomer is advanced to the direction of further technical upgrading and of scale down for light-weight structure as a sever rack. The first stage, basic properties of the urethane elastomer has been investigated by loading test. The second stage, the compression creep test with laminated type base isolation device has been investigated to confirm an effect on light-weight mechanical devices.
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Anderson, Walter, The Nguyen, and Mohammad Elahinia. "Vibration Mitigation With a Multi-Axial Magnetorheological Mount." In ASME 2009 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. ASMEDC, 2009. http://dx.doi.org/10.1115/smasis2009-1353.
Повний текст джерелаАнотація:
This paper presents a multi-axial magnetorheological (MMR) mount. An MMR mount has been developed for use with hydraulic hybrid vehicles (HHV). Like hybrid electric vehicles (HEV), HHV provides better fuel economy. An inherent problem to hydraulic hybrid vehicles is vibration of the hydraulic pump-motor (P/M). This vibration can be classified as shock loading for initial start-up, and periodic vibration over a large frequency range. The latter vibration opportunity can be classified as having large displacement at low frequency and small displacement at high frequency. This requires a stiff mount for the low frequency response and a soft mount for the high frequency response. A single axis magnetorheological (MR) mount has previously been developed and studied by the same group. This was done to develop an understanding of the MR fluid and to discover the limitations of such a mount. Models to predict the experimental results have also been generated. These models show a good correlation to the experimental results. Then, the model has been enhanced from the single axis mount to a multi-axial. This was done by examining the 3-D CAD model to develop the different boundary conditions for the simulation. With a multi-axial magnetorheological mount, damping and stiffness can be altered to yield acceptable transmissibility over the frequency range. This is achieved through the use of an inertia track paired with a pseudo-decoupler. These features are commonly found in a passive hydraulic mount; however through the use of MR fluid, the downfalls of the hydraulic mount can be mitigated, e.g. performance deterioration outside of notch frequency. Additionally, a magnetorheological mount is semi-active so there is an inherent stability to the mount. The MMR mount uses elastomer and MR fluid to achieve the static stiffness to support the P/M and achieve low dynamic stiffness for the high frequency response, which is necessary for a good isolator. The advantages of the use of a multi-axial magnetorheological mount are as follows: fewer mounts are required, stability when compared to an active mount, less power required when compared to an active mount, better isolation when compared to pure elastomeric and passive hydraulic mounts. A model for a multi-axial magnetorheological mount has been developed and simulated. For the purposes of this study, elastomer has been considered to have a linear dynamic response. Additionally, the shock response of the mount has not been considered. Future work includes manufacturing a multi-axial MR mount to verify the simulation results.
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Gupta, Sujasha, Srivatsava Krishnan, and Vishnubaba Sundaresan. "Structural Health Monitoring of Composite Structures via Machine Learning of Mechanoluminescence." In ASME 2019 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/smasis2019-5697.
Повний текст джерелаАнотація:
Abstract The goal of this paper is to develop a machine learning algorithm for structural health monitoring of polymer composites with mechanoluminescent phosphors as distributed sensors. Mechanoluminescence is the phenomenon of light emission from organic/inorganic materials due to mechanical stimuli. Distributed sensors collect a large amount of data and contain structural response information that is difficult to analyze using classical or continuum models. Hence, approaches to analyze this data using machine learning or deep learning is necessary to develop models that describe initiation of damage, propagation and ultimately structural failure. This paper focuses on developing a machine learning algorithm that predicts the elastic modulus of a structure as a function of input parameters such as stress and measured light output. The training data for the algorithm utilizes experimental results from cyclical loading of elastomeric composite coupons impregnated with ML particles. A multivariate linear regression is performed on the elastic modulus within the training data as a function of stress and ML emission intensity. Error in predicted elastic modulus is minimized using a gradient descent algorithm. The machine learning algorithm outlined in this paper is expected to provide insights into structural response and deterioration of mechanical properties in real-time that cannot be obtained using a finite array of sensors.