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1
Grosch, K. A. « The Rolling Resistance, Wear and Traction Properties of Tread Compounds ». Rubber Chemistry and Technology 69, no 3 (1 juillet 1996) : 495–568. http://dx.doi.org/10.5254/1.3538383.
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Abstract The paper gives a brief survey of the state of friction and abrasion research with a view of the possibility to use laboratory methods for the development of new compounds with optimal traction and abrasion properties. It shows that viscoelasticity plays a decisive role in friction and in this way measurements of the dynamic properties give a good indication of the possibilities for good traction properties. However, friction is still a good deal more complex than the modulus or loss factor curves. It takes in different frequency ranges and temperatures in the contact area so that a direct laboratory measurement of these properties is still very desirable. If the speed and temperature correspond to the log aTv values experienced in practice and the laboratory track structure and texture is not too far removed from that of road surfaces, the correlation with road tests is high. To simulate the structure and texture of road surfaces with durable laboratory surfaces, a combination of two surfaces may be necessary. Abrasion is not only influenced by the strength properties of the rubber but also by oxidation and thermal degradation. To give these processes the correct weight in the laboratory, the testing conditions have to be mild and a combination of several conditions is necessary in order to demonstrate the complexity of interactions, which can lead to ranking reversals. Energy dissipation, speed, and abrasive surface structure and texture are identified as prime variables to achieve a high correlation with road wear. Since viscoelasticity, encompassing not only polymer but also filler, oil-extension, curing and other compound additives, plays a major role in both friction and wear, the rolling resistance of the compound is always effected and has to be taken into account. Modern polymerization methods and new filler concepts make it possible to change the viscoelastic properties in such detail that high friction and—to the degree to which strength contributes to wear—high wear resistance can be combined with low rolling resistance. This development has certainly not reached its climax yet. Exciting times lie ahead for tire compounders, polymer- and filler chemists alike.
2
Zitelli, Pablo N., Gabriel N. Curtosi et Jorge Kuster. « Rolling Resistance Calculation Procedure Using the Finite Element Method ». Tire Science and Technology 48, no 3 (4 octobre 2019) : 224–48. http://dx.doi.org/10.2346/tire.19.170158.
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ABSTRACT Tire engineers are interested in predicting rolling resistance using tools such as numerical simulation and tests. When a car is driven along, its tires are subjected to repeated deformation, leading to energy dissipation as heat. Each point of a loaded tire is deformed as the tire completes a revolution. Most energy dissipation comes from the cyclic loading of the tire, which causes the rolling resistance in addition to the friction force in the contact patch between the tire and road. Rolling resistance mainly depends on the dissipation of viscoelastic energy of the rubber materials used to manufacture the tires. To obtain a good rolling resistance, the calculation method of the tire finite element model must take into account temperature changes. It is mandatory to calibrate all of the rubber compounds of the tire at different temperatures and strain frequencies. Linear viscoelasticity is used to model the materials properties and is found to be a suitable approach to tackle energy dissipation due to hysteresis for rolling resistance calculation.
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Curtosi, Gabriel N., Pablo N. Zitelli et Jorge Kuster. « Viscoelastic Material Calibration Procedure for Rolling Resistance Calculation ». Tire Science and Technology 47, no 3 (1 juillet 2019) : 232–56. http://dx.doi.org/10.2346/tire.19.170157.
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ABSTRACT As tire engineers, the authors are interested in predicting rolling resistance using tools such as numerical simulation and tests. When a car is driven along, its tires are subjected to repeated deformation, leading to energy dissipation as heat. Each point of a loaded tire is deformed as it completes a revolution. Most energy dissipation comes from the cyclic loading of the tire, which causes the rolling resistance in addition to the friction force in the contact patch between the tire and road. Rolling resistance mainly depends on the viscoelastic energy dissipation of the rubber materials used to manufacture the tires. To obtain an accurate amount of dissipated energy, a good understanding of the material mathematical model and its behavior is mandatory. For this reason, a calibration procedure was developed. To obtain a good method for calculating rolling resistance, it is necessary to calibrate all rubber compounds of the tire at different temperatures and strain frequencies. Thus, to validate the calibration procedure, simulations were performed to evaluate the error between the tests and models at material sample and tire levels. For implementation of the calibration procedure in the finite element models of rolling tires, a procedure is briefly described that takes into account the change in properties caused by the temperature during the simulations. Linear viscoelasticity is used to model the properties of the materials and is found to be a suitable approach to tackle energy dissipation due to hysteresis for rolling resistance calculation.
4
Bhave, Tejas, Mohammad Tehrani, Muhammad Ali et Alireza Sarvestani. « Hysteresis friction and nonlinear viscoelasticity of rubber composites ». Composites Communications 9 (septembre 2018) : 92–97. http://dx.doi.org/10.1016/j.coco.2018.07.001.
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Hemette, S., J. Cayer-Barrioz et D. Mazuyer. « Thermal effects versus viscoelasticity in ice-rubber friction mechanisms ». Tribology International 162 (octobre 2021) : 107129. http://dx.doi.org/10.1016/j.triboint.2021.107129.
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Roberts, Alan D. « RUBBER CONTACT PHENOMENA ». Rubber Chemistry and Technology 87, no 3 (1 septembre 2014) : 383–416. http://dx.doi.org/10.5254/rct.14.85982.
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ABSTRACT Research on rubber wiper blades led to the establishment of the now widely used Johnson, Kendall, Roberts (JKR) equilibrium equation that determines the strength of adhesion between surfaces. The equation was adapted to allow for the viscoelasticity of rubber, leading to explanations of how adhesion can impact on tack; rebound resilience; and rolling, static, and sliding friction. The adhesion of rubber to ice was found to depend on salt concentration in the ice, thus providing insight into winter tire performance. The development of optical techniques has greatly aided studies, particularly for measuring the thickness of thin liquid films sandwiched between rubber surfaces. Measurements on water films squeezed between rubber and glass revealed the action of repulsive surface forces that can reduce adhesion and friction. The efficacy of water lubrication depends upon whether surfactants are present and upon the acidity or alkalinity of the water. Improved understanding of adhesion and friction mechanisms offers design guidance for a range of rubber articles.
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Sullivan, J. L., et K. A. Mazich. « Nonseparable Behavior in Rubber Viscoelasticity ». Rubber Chemistry and Technology 62, no 1 (1 mars 1989) : 68–81. http://dx.doi.org/10.5254/1.3536236.
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Abstract New large-strain rubber viscoelasticity results for a filled and an unfilled IIR vulcanizate and previously published results for two NR gum vulcanizates have been discussed. The data show that the “mixed” response functions of large-strain stress relaxation, and the incremental storage and relaxation moduli do not demonstrate factorizability of time and strain effects. This is a consequence of the elastic and relaxation contributions in each of the mixed functions being different. The incremental dynamic data also show that the loss modulus for the filled IIR and unfilled NR vulcanizates (unavailable for the unfilled IIR) are separable functions of time and strain. This directly shows that the relaxation spectra for the filled IIR and unfilled NR vulcanizates are independent of strain for the deformations studied. In fact, it is argued that a necessary and sufficient condition for the relaxation spectrum to be independent of strain is that the loss modulus is a factorizable function of time and strain effects. The quantitative success of the Generalized Solid-Liquid (GSL) model in representing the viscoelastic behavior of the gum NR vulcanizate has been reviewed. Although the GSL model applies only to unfilled vulcanizates, it has also been successfully used to qualitatively interpret the results for the filled IIR compounds. Both successes are attributed to the physical assumptions intrinsic to the GSL model; more specifically, 1) the relaxation spectrum is independent of the state of strain, and 2) the deformational dependences of elastic and relaxation contributions to the overall response of the system need not be the same. Physical arguments justifying these assumptions have been covered. It has also been shown with the aid of the GSL model, that a material might exist which demonstrates factorizability in stress relaxation and incremental loss modulus behaviors but nonfactorizability in the incremental storage and relaxation moduli.
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Schapery, R. A. « The effect of global viscoelasticity on rubber friction with Schallamach waves ». Tribology International 148 (août 2020) : 106306. http://dx.doi.org/10.1016/j.triboint.2020.106306.
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Falk, Korbinian, Ronny Lang et Michael Kaliske. « Multiscale Simulation to Determine Rubber Friction on Asphalt Surfaces ». Tire Science and Technology 44, no 4 (1 octobre 2016) : 226–47. http://dx.doi.org/10.2346/tire.16.440401.
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ABSTRACT The interaction between rubber and asphalt pavement depends on the roughness characteristics of the road surface, as well as the contact pressure, slip velocity, and temperature. A homogenization procedure of rubber friction, based on the finite element method, is presented, in order to gain surface dependent friction properties by numerical simulation. Furthermore, the method allows a deep insight into microscale phenomena, like real contact area, microscopic contact pressure, or flash temperature. Rubber undergoes large deformations in contact with rough surfaces. Therefore, the material characteristics of rubber need to be modeled by hyperelasticity and viscoelasticity at finite deformations and dependent on temperature. Thus, hysteresis friction, originating in energy dissipation of the bulk material, i.e., the viscoelastic properties, is evaluated. Adhesion friction is a phenomenon associated with the real contact area and is included in the proposed methodology by a physically motivated, fracture mechanical approach. The resulting macroscopic friction features are validated by experiments based on a linear friction tester. Analytical state of the art solutions are compared with the numerical results.
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Tolpekina, T. V., et B. N. J. Persson. « Adhesion and Friction for Three Tire Tread Compounds ». Lubricants 7, no 3 (26 février 2019) : 20. http://dx.doi.org/10.3390/lubricants7030020.
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We study the adhesion and friction for three tire tread rubber compounds. The adhesion study is for a smooth silica glass ball in contact with smooth sheets of the rubber in dry condition and in water. The friction studies are for rubber sliding on smooth glass, concrete, and asphalt road surfaces. We have performed the Leonardo da Vinci-type friction experiments and experiments using a linear friction tester. On the asphalt road, we also performed vehicle breaking distance measurements. The linear and non-linear viscoelastic properties of the rubber compounds were measured in shear and tension modes using two different Dynamic Mechanical Analysis (DMA) instruments. The surface topography of all surfaces was determined using stylus measurements and scanned-in silicon rubber replicas. The experimental data were analyzed using the Persson contact mechanics and rubber friction theory.
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Muraoka, Kiyoshige, Takeshi Ohta, Hiromasa Ohkubo, Noriko Yagi et Toshiro Masuda. « Effects of Deformation History on Viscoelasticity of Filled Rubber Compounds ». NIPPON GOMU KYOKAISHI 76, no 11 (2003) : 405–9. http://dx.doi.org/10.2324/gomu.76.405.
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Popov, I., et A. Levchenko. « EXPERIMENTAL INVESTIGATION OF INTERNAL FRICTION IN RUBBER CONCRETE AND FIBER-REINFORCED RUBBER CONCRETE ». Russian Journal of Building Construction and Architecture, no 4(52) (19 novembre 2021) : 53–62. http://dx.doi.org/10.36622/vstu.2021.52.4.005.
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Statement of the problem. The paper is devoted to the experimental identification of damping for such materials as butadiene rubber (BR) and cis-butadiene low-molecular weight rubber (SKDN-N) based concrete and fiber-reinforced rubber concrete by means of the Impulse Excitation Technique (IET). Results. It was found that BR based concrete with or without fiber-reinforcement shows more obvious viscoelastic properties than the corresponding materials based on SKDN-N rubber. The addition of steel fiber reduces internal friction in the material, while propylene fiber has the opposite effect. This is due to the fact that the fibrous propylene acts as an additional damping material, which enhances energy dissipation under dynamic loading.Conclusion. The internal friction in the rubber concrete and fiber-reinforced rubber concrete was measured for the first time. The obtained data are the additional microstructural characteristics of polymer concrete, which describes its viscosity. The real values of the investigated quantities have been determined, which makes it possible to use the models with fractional derivatives in the calculations of building structures made of rubber concrete and fiber-reinforced rubber concrete for dynamic loads, taking into account the phenomenon of viscoelasticity.
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Leblanc, Jean L. « Nonlinear Viscoelasticity of (Unvulcanized) Natural Rubber, Derived Materials, and Compounds Through LAOS Testing ». Rubber Chemistry and Technology 83, no 1 (1 mars 2010) : 65–96. http://dx.doi.org/10.5254/1.3548267.
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Abstract Natural rubber (NR) is by far the most important elastic material but its production specifications remain relatively poor when compared to synthetic elastomers. The so-called technically specified NR grades (i.e., technically specified rubber) are indeed characterized with respect to basic rubber test techniques, such as the Mooney viscosity, the (Wallace) plasticity (P0), and the Plasticity Retention Index, but high elasticity grades like ribbed smoked sheets are classified with respect to visual inspection criteria only. In addition, NR exhibits by nature more variation than synthetic polymers, owing to inevitable production differences from around 50 different clones of Hevea Brasiliensis, which are further enhanced by climate, soil, and other local effects, as well as seasonal effects on tapping. Most rubber processing operations occur at high rates of strain, and therefore it is essentially the nonlinear viscoelastic response of rubber materials that is of interest. This prompted the development of advanced investigation testing, such as large amplitude oscillatory strain (LAOS) experiments, which over the last decade were developed into powerful techniques to document the nonlinear viscoelastic behavior of polymer materials. First, the standard rheological tests for characterizing gum NR grades are briefly reviewed and discussed. Second, the equipment, test protocols, data treatment, and results modeling necessary to apply nonlinear viscoelastic testing are presented. Third, a number of LAOS experimental results obtained on various grades of NR, on a few chemically modified NR materials, and on two carbon black-filled NR compounds are reported and discussed.
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Fortunato, Gaetano, Vincenzo Ciaravola, Alessandro Furno, Michele Scaraggi, Boris Lorenz et Bo N. J. Persson. « Dependency of Rubber Friction on Normal Force or Load : Theory and Experiment ». Tire Science and Technology 45, no 1 (1 janvier 2017) : 25–54. http://dx.doi.org/10.2346/tire.17.450103.
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ABSTRACT In rubber friction studies, it is often observed that the kinetic friction coefficient μ depends on the nominal contact pressure p. We discuss several possible origins of the pressure dependency of μ: (1) saturation of the contact area (and friction force) due to high nominal squeezing pressure; (2) nonlinear viscoelasticity; (3) nonrandomness in the surface topography, in particular the influence of the skewness of the surface roughness profile; (4) adhesion; and (5) frictional heating. We show that in most cases the nonlinearity in the μ(p) relation is mainly due to process (5), frictional heating, that softens the rubber, increases the area of contact, and (in most cases) reduces the viscoelastic contribution to the friction. In fact, because the temperature distribution in the rubber at time t depends on the sliding history (i.e., on the earlier time t′ < t), the friction coefficient at time t will also depend on the sliding history, that is, it is, strictly speaking, a time integral operator. The energy dissipation in the contact regions between solids in sliding contact can result in high local temperatures that may strongly affect the area of real contact and the friction force (and the wear-rate). This is the case for rubber sliding on road surfaces at speeds above 1 mm/s. Previously, we derived equations that described the frictional heating for solids with arbitrary thermal properties. Here, the theory is applied to rubber friction on road surfaces. Numerical results are presented and compared to experimental data. We observe good agreement between the calculated and measured temperature increase.
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Liu, Ying, Wenduo Chen et Dazhi Jiang. « Review on Heat Generation of Rubber Composites ». Polymers 15, no 1 (20 décembre 2022) : 2. http://dx.doi.org/10.3390/polym15010002.
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Rubber composites are extensively used in industrial applications for their exceptional elasticity. The fatigue temperature rise occurs during operation, resulting in a serious decline in performance. Reducing heat generation of the composites during cyclic loading will help to avoid substantial overheating that most likely results in the degradation of materials. Herein, we discuss the two main reasons for heat generation, including viscoelasticity and friction. Influencing factors of heat generation are highlighted, including the Payne effect, Mullins effect, interface interaction, crosslink density, bond rubber content, and fillers. Besides, theoretical models to predict the temperature rise are also analyzed. This work provides a promising way to achieve advanced rubber composites with high performance in the future.
16
Gerspacher, M., C. P. O'Farrell, L. Nikiel, H. H. Yang et F. Le Méhauté. « High Frequency Viscoelasticity of Carbon Black Filled Compounds ». Rubber Chemistry and Technology 69, no 5 (1 novembre 1996) : 786–800. http://dx.doi.org/10.5254/1.3538402.
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Abstract A high frequency viscoelasticity spectrometer, using the state-of-the-art ultrasonic technology, was constructed. The longitudinal and shear waves characteristics were measured in rubber compounds to obtain the attenuation coefficient, α, and sound velocity, v Preliminary results were obtained for a number of filled and unfilled polymers. The grade of carbon black used, filler loading, crosslinking density and filler dispersion were varied during the study. Temperature sweepS from −100°C to +60°C were also studied. It was found that the polymer type had a greater influence on α and v than did the grade of carbon black, loading or dispersion. The experimental data show that shear waves do not propagate in the rubbery state. Above the glass transition temperature, Tg, the longitudinal wave measurements could be sufficient to determine the high frequency dynamic properties of filled and unfilled polymers to characterize a tire tread compound. The temperature sweep measurements allowed the determination of the Tg of polymers at high frequency. It is proposed that the described method of measuring α and v be used as a laboratory tool for potential tire traction prediction.
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Попов, И. И., et А. В. Левченко. « Experimental Investigation of Internal Friction in Rubber Concrete and Fiber-Reinforced Rubber Concrete ». НАУЧНЫЙ ЖУРНАЛ СТРОИТЕЛЬСТВА И АРХИТЕКТУРЫ, no 4(64) (22 décembre 2021) : 83–92. http://dx.doi.org/10.36622/vstu.2021.64.4.008.
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Постановка задачи. Работа посвящена экспериментальному определению внутреннего трения в таких материалах, как каучуковые бетоны (каутоны) на основе низкомолекулярного полибутадиенового каучука смешанной микроструктуры марки ПБН и цис-полибутадиенового низкомолекулярного каучука марки СКДН-Н, с помощью метода импульсного воздействия. Результаты. Установлено, что каутон на основе каучука марки ПБН обладает более выраженными вязкоупругими свойствами по сравнению с аналогичным материалом на основе каучука марки СКДН-Н. Введение стальной фибры снижает внутреннее трение в материале, в то время как полимерная фибра дает обратный эффект. Это связано с тем, что волокнистая пропиленовая фибра служит дополнительным демпфирующим материалом, усиливающим диссипацию энергии при динамическом нагружении. Выводы. Впервые измерено внутреннее трение для каутона и фиброкаутона. Полученные данные являются дополнительными микроструктурными характеристиками материалов, описывающими их вязкость. Определены реальные значения исследуемых величин, которые позволяют применять модели с дробными производными при расчете строительных конструкций из каутона и фиброкаутона на динамические воздействия с учетом явления вязкоупругости. Statement of the problem. The paper is devoted to the experimental identification of damping for such materials as butadiene rubber (BR) and cis-butadiene low-molecular weight rubber (SKDN-N) based concrete and fiber-reinforced rubber concrete by means of the Impulse Excitation Technique (IET). Results. It was found that BR based concrete with or without fiber-reinforcement shows more obvious viscoelastic properties than the corresponding materials based on SKDN-N rubber. The addition of steel fiber reduces internal friction in the material, while propylene fiber has the opposite effect. This is due to the fact that the fibrous propylene acts as an additional damping material, which enhances energy dissipation under dynamic loading. Conclusion. The internal friction in the rubber concrete and fiber-reinforced rubber concrete has been measured for the first time. The obtained data are the additional microstructural characteristics of polymer concrete, which describes its viscosity. The actual values of the investigated quantities have been determined, which makes it possible to use the models with fractional derivatives in the calculations of building structures made of rubber concrete and fiber-reinforced rubber concrete for dynamic loads taking into account the phenomenon of viscoelasticity.
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Medalia, Avrom I. « Heat Generation in Elastomer Compounds : Causes and Effects ». Rubber Chemistry and Technology 64, no 3 (1 juillet 1991) : 481–92. http://dx.doi.org/10.5254/1.3538565.
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Abstract In many important applications, an elastomer is subjected to repeated deformations of sufficient magnitude and frequency to lead to generation of considerable heat and (depending on the rate of heat removal) of a significant rise in temperature. The purpose of this review is to examine the mechanisms of heat generation and to indicate some important effects arising in service. More detailed discussion of various aspects of heat generation, dynamic properties, and viscoelasticity of rubber compounds may be found elsewhere.
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Martinez-Martinez, D., J. P. van der Pal, Y. T. Pei et J. Th M. De Hosson. « Performance of diamond-like carbon-protected rubber under cyclic friction. II. Influence of substrate viscoelasticity on the friction evolution ». Journal of Applied Physics 110, no 12 (15 décembre 2011) : 124907. http://dx.doi.org/10.1063/1.3665445.
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Karl, Janis, Franziska Kirsch, Norbert Faderl, Leonhard Perko et Teresa Fras. « Optimizing Viscoelastic Properties of Rubber Compounds for Ballistic Applications ». Applied Sciences 10, no 21 (5 novembre 2020) : 7840. http://dx.doi.org/10.3390/app10217840.
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Using interlayers of rubber adds a positive effect to the synergy of disruptor–absorber armors. Emerging from its viscoelasticity the material is able to transform mechanical stress into heat. The dynamic mechanical properties of elastomers depend on both ambient temperature and frequency of an applied mechanical load. The damping shows a maximum in the glass transition area. If the frequency of the glass transition is in the magnitude of the mechanical stress rate applied by ballistic impact, the elastomer will undergo the transition and thus show maximized damping. An ideal material for ballistic protection against small calibers is developed by making use of dynamic mechanical analysis and the time–temperature superposition principle. The material is later analyzed by ballistic experiments and compared to other nonideal rubbers with regard to glass transition temperature, hardness and damping. It is shown that by choosing a material correctly with certain glass transition temperature and hardness, the ballistic properties of a steel–rubber–aluminum armor can be enhanced. The chosen material (butyl rubber) with a hardness of 50 °ShA is able to enhance energy absorption during ballistic impact by around 8%, which is twice as good as other rubber with non-optimized properties.
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Kaang, Shinyoung, Jaepyoung Cho, Seungjai Kim, Changwoon Nah et Choon Tack Cho. « Friction and Wear of Rubber Compounds Containing Powdered Polynorbornene Vulcanizate ». Journal of Polymer Engineering 18, no 1-2 (1 mars 1998) : 83–100. http://dx.doi.org/10.1515/polyeng-1998-1-208.
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Abstract An investigation on the frictional performance of a natural rubber compound containing polynorbomene (PN) vulcanizate powder was carried out at various temperatures between -20°C and 60°C. The glass transition temperature, Tg, of the PN vulcanizate was 15°C. At temperatures below its Tg, the frictional coefficient of the composite significantly increased to the extent of 10% with a 10 phr addition of PN vulcanizate powder, while the wear rates were not greatly affected. The wear behavior of the composite was strongly dependent on the frictional work input.
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Bae, Jung-Eun, Kwang Soo Cho, Kwan Ho Seo et Dong-Gug Kang. « Application of geometric algorithm of time-temperature superposition to linear viscoelasticity of rubber compounds ». Korea-Australia Rheology Journal 23, no 2 (juin 2011) : 81–87. http://dx.doi.org/10.1007/s13367-011-0011-9.
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Pan, Xiao-Dong, Edward D. Kelley et Michael W. Hayes. « Bulk viscoelastic contribution to the wet-sliding friction of rubber compounds ». Journal of Polymer Science Part B : Polymer Physics 41, no 8 (13 mars 2003) : 757–71. http://dx.doi.org/10.1002/polb.10429.
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Klüppel, Manfred, et Gert Heinrich. « Rubber Friction on Self-Affine Road Tracks ». Rubber Chemistry and Technology 73, no 4 (1 septembre 2000) : 578–606. http://dx.doi.org/10.5254/1.3547607.
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Abstract A basic theoretical concept of rubber friction on rough surfaces is presented that relates the frictional force to the dissipated energy of the rubber during sliding stochastic excitations on a broad frequency scale. It is shown that this is of high relevance for tire traction and allows for a prediction of the likely level of friction of tread compounds on the basis of viscoelastic data. The impact of both, the frequency dependent loss- and storage modulus on the frictional force during sliding of tires on rough tracks, is demonstrated quantitatively for different sliding velocities. The effect of the surface roughness of road tracks is described by three characteristic surface descriptors, i.e., the fractal dimension and the correlation lengths parallel and normal to the surface. These descriptors can be obtained from a fractal analysis of the road texture via stylus- or laser measurements. In particular, it is shown that the applied model of rubber friction is in agreement with the classical friction data of Grosch, who found a broad maximum for the friction coefficient with increasing sliding speed. The broadness of the friction maximum is shown to be directly related to the broadness of the roughness scale of the surface.
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Pan, Xiao-Dong, Paul Zakelj, Cara Adams, Akiko Neil et Greg Chaplin. « Understanding Wet Skid Resistance Testing with the British Pendulum Skid Tester : Analysis of Sliding Noise from Various Filled Compounds ». Rubber Chemistry and Technology 83, no 1 (1 mars 2010) : 97–122. http://dx.doi.org/10.5254/1.3548268.
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Abstract The British pendulum skid tester (BPST) has been widely adopted for laboratory characterization of wet skid resistance (WSR) for rubber compounds. However, testing results are not yet well explained with material properties. For filled compounds made of the same styrene-butadiene rubber, on a Portland cement concrete surface wetted with water, WSR for compounds filled with inorganic oxides is higher than WSR for compounds filled with carbon black at the same filler volume fraction. However, such difference in WSR is eliminated under ethanol lubrication. Difference in WSR remains under ethanol lubrication between compounds filled with a reinforcing filler and compounds filled with a nonreinforcing filler. Accepting that dynamic deformation of rubber occurs in the frequency range between 103 and 106 Hz during testing with the BPST, loss tangent for the compounds is measured at various low temperatures but fails to correlate with WSR detected under water lubrication. Modification of bulk viscoelasticity from ethanol absorption should not be neglected for consideration of WSR under ethanol lubrication. During testing with the BPST, sliding noise generated by the assemblage of the spring and lever system in the pendulum with a rubber slider attached is captured under varied lubrication conditions. Both viscoelastic properties of rubber compounds and lubrication condition significantly affect sliding noise. However, no strict correlation between the intensity of sliding noise and WSR is observed. From frequency domain analysis, major components of the sliding noise lie in the frequency range between 500 and 5000 Hz for most compounds. For better understanding on testing with the BPST, modes of material deformation during dynamic sliding on a wet rough surface need to be further scrutinized.
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Tolpekina, T., W. Pyckhout-Hintzen et B. N. J. Persson. « Linear and Nonlinear Viscoelastic Modulus of Rubber ». Lubricants 7, no 3 (8 mars 2019) : 22. http://dx.doi.org/10.3390/lubricants7030022.
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We study the linear and nonlinear viscoelastic properties of two tire tread compounds. We discuss the difference in nonlinear response between the oscillatory tensile and shear modes. We also analyze strain relaxation (creep) data for the same systems. We discuss what type of measurements are most suitable for obtaining the viscoelastic modulus used in rubber friction calculations.
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UMANO, Hiroshi, et Hiroshi YAMAURA. « G-3 Characteristics of paper feeding mechanism dependences on paper feeding velocity : Effect of rubber viscoelasticity and friction coefficient of rubber and paper ». Proceedings of the Conference on Information, Intelligence and Precision Equipment : IIP 2010 (2010) : 230–35. http://dx.doi.org/10.1299/jsmeiip.2010.230.
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Paramasivam, Prabhakaran, Rajasekar Rathanasamy, Rajesh Ranganathan, Sathish Kumar Palaniappan et Samir Kumar Pal. « Husking and mechanical properties of ISAF N231/SAF N110 carbon black filled XNBR-ENR blend rubber compound for rice husk removal applications ». Materials Testing 63, no 8 (1 août 2021) : 783–87. http://dx.doi.org/10.1515/mt-2020-0112.
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Abstract White rice kernels are produced in the rice milling process with the help of rubber rollers. Husks are removed from paddy due to friction between the surface of rubber rollers and the paddy layer when the paddy passes between the two rubber rollers [1, 2, 3, 4, 5, 6]. Improved physico-mechanical properties of rubber compounds are needed for husk removal. Based on this review, it was found that small scale rice processing mills in Tamil Nadu, India face the problem of the poor service life of rubber rollers. Rubber compounds with a greater hardness are better for husking rice but breakage in the rice is high. Rice breakage can be minimized when soft rubber is used but the wear rate for soft rubber is high [6, 7, 8, 9, 10, 11, 12]. This study discusses the production of new rubber compounds produced by substituting the proportions of carboxylated nitrile butadiene rubber (XNBR) and epoxidized natural rubber (ENR) with two different carbon blacks. Physico-mechanical properties and lab scale rice-husk separation studies are conducted for these rubber compounds developed. The conclusion is that XNBR- ENR blends with ISAF N231 variety of carbon black prove to be suitable materials for husk removal applications.
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Schapery, R. A. « Corrigendum to “The effect of global viscoelasticity on rubber friction with Schallamach waves” [Tribol. Int. 148 (2020) 106306] ». Tribology International 151 (novembre 2020) : 106527. http://dx.doi.org/10.1016/j.triboint.2020.106527.
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MELNIKOV, OLEG M. « IMPROVING SEALING ELEMENTS OF THE BEARING ASSEMBLY OF AGRICULTURAL MACHINERY ». Agricultural engineering, no 3 (2022) : 68–72. http://dx.doi.org/10.26897/2687-1149-2022-3-68-72.
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At present, it is necessary to improve not only repair technologies, but also consider the possibility of using various modified materials to increase the post-repair reliability of agricultural machinery. One of the ways to improve the rubber seals of bearing assemblies is to modify them by adding organofluorine compounds to the rubber composition, which have a complex effect on rubber, improve its physical, mechanical, and tribological properties. To determine the modification effect of seals on friction and wear, the author tested joints consisting of a steel bushing with a diameter of 45 mm with a surface hardness of at least HRC32 and collars of three types: serial (GOST 8752-79); modified with alcohol-telomer (FS-1) and fluoroparaffin (FS-2) in the amount of one mass part of PS per 100 mass parts of rubber. The collar wear was determined by changing the width of the working edge, measured by DIP-6 with the optoelectronic measuring system NIIK-890. Bench tests showed that volumetric modification with organofluorine compounds improved the properties of rubber: the wear of modified seals decreased in 1.83…1.94 times compared to serial ones, friction coefficient decreased in 1.32…1.37 times
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Vaikuntam, Sankar Raman, Eshwaran Subramani Bhagavatheswaran, Fei Xiang, Sven Wießner, Gert Heinrich, Amit Das et Klaus Werner Stöckelhuber. « Friction, Abrasion and Crack Growth Behavior of In-Situ and Ex-Situ Silica Filled Rubber Composites ». Materials 13, no 2 (7 janvier 2020) : 270. http://dx.doi.org/10.3390/ma13020270.
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The article focuses on comparing the friction, abrasion, and crack growth behavior of two different kinds of silica-filled tire tread compounds loaded with (a) in-situ generated alkoxide silica and (b) commercial precipitated silica-filled compounds. The rubber matrix consists of solution styrene butadiene rubber polymers (SSBR). The in-situ generated particles are entirely different in filler morphology, i.e., in terms of size and physical structure, when compared to the precipitated silica. However, both types of the silicas were identified as amorphous in nature. Influence of filler morphology and surface modification of silica on the end performances of the rubbers like dynamic friction, abrasion index, and fatigue crack propagation were investigated. Compared to precipitated silica composites, in-situ derived silica composites offer better abrasion behavior and improved crack propagation with and without admixture of silane coupling agents. Silane modification, particle morphology, and crosslink density were identified as further vital parameters influencing the investigated rubber properties.
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Nayek, Suprakash, Anil K. Bhowmick, Samir K. Pal et Arup K. Chandra. « Wear Behavior of Silica Filled Tire Tread Compounds by Various Rock Surfaces ». Rubber Chemistry and Technology 78, no 4 (1 septembre 2005) : 705–23. http://dx.doi.org/10.5254/1.3547908.
Texte intégralRésumé :
Abstract Wear of silica filled tire tread compounds made from natural rubber (NR) and styrene butadiene rubber (SBR) against various rock surfaces at different normal loads and frictional work was investigated. The rocks chosen, i.e. granite, quartzite, limestone and shale, had variation in hardness and chemical composition. Wear, V, increased with normal load, N and frictional work, Fw, and these were related by V=βNα and V=k Fw n, where β,α,k and n were constants and dependent on the nature of the abraded surface and the rubber. The rate of wear of SBR was found to be much lower than that of NR against all rock surfaces. All the results could be explained with the help of dynamic co-efficient of friction, frictional work and structural changes during abrasion. The rate of wear as well as the dynamic coefficient of friction decreased with silica filler loading up to certain loading and then increased. These were 60 phr silica for NR and 70 phr silica for SBR. The surfaces of NR and SBR when abraded against different rock surfaces became tarry on prolonged abrasion. The debris were oily and aggregated for NR compound and were particulate for SBR compound. The debris and the ridges were analyzed by an image processing technique.
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Pan, X. D. « Significance of Tuning Bulk Viscoelasticity via Polymer Molecular Design on Wet Sliding Friction of Elastomer Compounds ». Tribology Letters 20, no 3-4 (décembre 2005) : 209–19. http://dx.doi.org/10.1007/s11249-005-8372-1.
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Ignatyev, Pavel A., Stefan Ripka, Norbert Mueller, Stefan Torbruegge et Burkhard Wies. « Tire ABS-Braking Prediction with Lab Tests and Friction Simulations ». Tire Science and Technology 43, no 4 (1 octobre 2015) : 260–75. http://dx.doi.org/10.2346/tire.15.430401.
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ABSTRACT The invention and application of antilock braking systems (ABS) has resulted in a significant improvement of traffic safety and a reduction of stopping distance, especially on wet roads [1]. The reason for this success is rather clear: ABS is designed to steer the braking process in the most efficient way by keeping an optimal level of tire slip. At the same time, it must be clear that ABS uses braking forces generated in the tire footprint, and really good braking is possible only with high-performance tires. The best way to probe tire performance is to build tires and test them. This is, however, a long and an expensive procedure, so prediction of ABS performance based on results of some simple experiments is a very attractive supplement to the development process. Tire-braking performance is related to the friction of rubber on a surface. Relevant friction mechanisms can include adhesion, rubber hysteresis, and various kinds of viscous friction. All of these phenomena depend on the local sliding velocity, load, and temperature of tread rubber. Tire blocks pass the footprint area of a braking tire very rapidly, but their dynamics are indeed influenced by ABS. All of these aspects make the problem of ABS-braking prediction very intricate. In this publication, we present an approach for prediction of the ABS-braking performance. The approach links friction measurements conducted in laboratory to tire tests results. The friction of six specially designed compounds was measured on dry and wet surfaces using a high-speed linear friction test rig. Obtained experimental results are analyzed with the aid of rubber friction theory [2,3] involving both surface and rubber as input parameters. It is demonstrated that lab friction test procedures can be used for prediction of ABS wet braking performance.
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Martinez-Martinez, D., J. P. van der Pal, Y. T. Pei et J. Th M. De Hosson. « Performance of diamond-like carbon-protected rubber under cyclic friction. I. Influence of substrate viscoelasticity on the depth evolution ». Journal of Applied Physics 110, no 12 (15 décembre 2011) : 124906. http://dx.doi.org/10.1063/1.3665443.
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Thavamani, P., et Anil K. Bhowmick. « Wear of Tank Track Pad Rubber Vulcanizates by Various Rocks ». Rubber Chemistry and Technology 65, no 1 (1 mars 1992) : 31–45. http://dx.doi.org/10.5254/1.3538606.
Texte intégralRésumé :
Abstract Wear of tank track pad compounds against various rocks at different normal loads and frictional work has been investigated. The track pads have been based on natural rubber (NR) and hydrogenated nitrile rubber (HNBR). The rocks have various hardness and chemical compositions. Wear, V, increases with normal load, N, and frictional work, F, and is related by V=KFn, where k and n are constants. The value of n is lower for filled compounds and abrasion against soft rock. At any normal load, the rate of wear of HNBR is much lower than that of NR, though the temperature developed is higher for HNBR compounds. All the results could be explained with the help of dynamic coefficient of friction, frictional work, and structural changes during abrasion. Ridges are found on the abraded surface of NR, and the surface is tarry. A dry and particulate wear is observed in HNBR compounds, and the size of debris increases with frictional work.
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Amino, N., Y. Uchiyama, T. Iwai et M. Maeda. « Studies of Friction Mechanism in Silica and Carbon Black Filled SBR : (3) Friction of Carbon Black and Silica Filled SBR Blends ». International Polymer Science and Technology 30, no 4 (avril 2003) : 13–20. http://dx.doi.org/10.1177/0307174x0303000405.
Texte intégralRésumé :
Tire tread compounds usually consist of polymer blends. In this paper the friction for immiscible SBR blends which consist of two different SBRs having different glass transition temperatures of −51 °C and −6 °C are investigated. The effects of the blend ratio of these two SBRs and the added fillers such as carbon black and silica on the friction are also investigated. The friction forces are measured when rubber specimens are rubbed against dry or wet metal gauze. The friction force-sliding speed curves for the SBR blends are related to their storage modulus E′, loss tangent tan δ, contact area A and shear strength s. The adhesion component of the friction for each SPR blend shows a peak at the sliding speed range examined. As the blend ratio of the SBR having higher Tg of −6 °C is raised, the peak value is lowered and the peak shifts to lower sliding speed. The adhesion component of the friction for silica-filled SBR blends is higher than that of carbon black-filled SBR blends. These trends are also shown when rubber specimens are rubbed against the wet metal gauze. On the other hand, the hysteresis component of friction is raised when the blend ratio of the SBRs having higher Tg is increased.
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Pan, Yiren, Deshang Han, Lin Zhu, Meng Zhang, Huiguang Bian, Chuansheng Wang et Wenwen Han. « Effect of Adding MoDTC on the Properties of Carbon Black Rubber and the Friction and Wear of Metal during Mixing Process ». Materials 13, no 5 (28 février 2020) : 1071. http://dx.doi.org/10.3390/ma13051071.
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The gap between the rotor and the mixer chamber wall is an important factor in determining filler dispersion in rubber compounds. The inner wall of a mixer will wear after working for a long time, which will cause poor filler dispersion and affect the quality of rubber products. In this study, MoDTC was added to carbon black as a kind of filler, and the effect on filler dispersion, the properties of the rubber product, and the friction and wear of rubber and metal in the mixing process were examined. Experimental data showed that after adding 3 phr of MoDTC, carbon black dispersion was greatly improved, the curing time was shortened, and the performance remained stable. It was also found that the Mo element of the compound with 3 phr MoDTC dispersed better than that of the other compounds. Most importantly, adding 3 phr of MoDTC greatly reduced the amount of wear on the metal during the mixing process. However, the opposite effect occurred when the MoDTC content was high. The method proposed in this study can not only improve filler dispersion in rubber but also reduce metal wear to prolong the service life of the mixing chamber when applied to an actual mixing process.
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Grosch, K. A. « Goodyear Medalist Lecture. Rubber Friction and its Relation to Tire Traction ». Rubber Chemistry and Technology 80, no 3 (1 juillet 2007) : 379–411. http://dx.doi.org/10.5254/1.3548172.
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Abstract Rubber friction differs from that of hard solid materials in that it is not linearly related to the normal load and it depends strongly on sliding speed and temperature. There exists an interrelation between these two variables on their effect on the friction coefficient, first observed for the viscosity of liquids and generally described by the universal WLF transformation equation. The friction coefficient at a constant load is then described by a so-called master curve. Such master curves have been obtained on different types of surface and for gum rubbers as well as filled rubbers on wet and dry surfaces and it is shown that they may also be obtained on ice. The shape of the curve and position on the log(aTv) axis depends on the polymer and the track surface structure indicating that two distinct processes determine the friction: adhesion friction akin to a molecular relaxation process and a deformation process in which energy is lost due to the cyclic deformation of the rubber by the surface asperity. To obtain such a master curve it is necessary to keep the experimental speeds so low that the temperature rise in the contact area can be neglected. In practical tire tests, sliding speeds are high and hence the temperature rises with speed. Since the WLF equation is a negative function of temperature, the range of log(aTv) is limited. If thermocouples are used as sliders on rubber, it is shown that the experimental curves as function of speed can be transformed into a part of a master curve. For compound development friction tests, a limited range of track temperatures and speeds are sufficient to ensure a high correlation with road test data. A single point laboratory measurement may correlate with road tests if carefully chosen. More usually, it leads to misleading conclusions. Side force measurements at a reasonably large slip angle also reflect the friction coefficient and are a useful laboratory tool to evaluate the traction properties of tread compounds.
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Leblanc, Jean L., et Christophe de la Chapelle. « Updating a Torsional Dynamic Rheometer for Fourier Transform Rheometry on Rubber Materials ». Rubber Chemistry and Technology 76, no 2 (1 mai 2003) : 287–98. http://dx.doi.org/10.5254/1.3547743.
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Abstract A torsional dynamic rheometer has been suitably modified in order to collect actual torque and strain data, in view of studying the non-linear viscoelastic region. Essentially a fast electronic analogic - digital conversion card is used to record and treat torque and strain signals using a purposely written software. A Fast Fourier Transform (FFT) algorithm was first used in order to resolve recorded signals in harmonic peak components. Preliminary investigations were conducted with pure elastomers and filled rubber compounds in order to asses the testing capabilities of the system. As expected, when the non-linear viscoelastic response of a pure, unfilled rubber is produced through increasing strain amplitude, a number of significant odd-harmonic peaks appear in the Fourier Transform Spectrum (FTS). When testing intrinsically non-linear materials such as carbon-black filled rubber compounds, FFT gives also significant odd-harmonics whose relative intensities growth with filler content. Fourier transform rheology has therefore the capability to truly investigate non-linear viscoelasticity but cannot at first sight distinguish between the non-linear behavior appearing upon increasing strain amplitude (extrinsic non-linearity) and the non-linear behavior that reflects the complex heterogeneity of the material (intrinsic non-linearity). Other data analysis techniques were thus investigated; for instance, the detail examination of the actual shape of half-period torque signals. It appears that torque signal distortions are different providing they are obtained either through larger strain amplitude tests on pure polymer or by increasing filler content.
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Li, Wei, et Yihui Chen. « Effects of Different Metals on Properties and Friction and Wear of Composite Materials ». Polymers 14, no 21 (26 octobre 2022) : 4545. http://dx.doi.org/10.3390/polym14214545.
Texte intégralRésumé :
With the vigorous development of the automobile industry, the rubber industry has also made continuous progress. As necessary mixing equipment in the rubber industry, the internal mixer is required to undertake a lot of constant work for a long time, which inevitably causes wear to the internal mixer. On the one hand, the wear of the metal on the end face of the internal mixer will lead to an increase in the gap between the inner mixing chamber and the end face, which will lead to material leakage, affect the material ratio of the rubber mixture, and ultimately affect the performance of the rubber mixture. On the other hand, the wear of the end metal of the internal mixer is an increasing process, and the tiny metal particles of the end metal will be incorporated into the rubber mix along with the mixing process, affecting the performance of the rubber mix. At the same time, the disassembly and repair of the internal mixer are complex, and the end face maintenance is difficult. Therefore, finding a kind of end face metal with good wear resistance, long service life, and no influence on rubber compound performance is essential. This paper takes the end face metal of the internal mixer with severe wear as the research object. The wear degree of the metal after friction between MCYD-4 alloy, YW-15 alloy, wear-resistant stainless steel, tungsten carbide alloy, and the rubber compound is compared. The changes in the properties of the compounds after rubbing were investigated. The study found that the tensile tear properties, wet skid resistance, and rolling resistance of NR/BR composites differed when different end-face metals were selected for mixing, but the gap was small. When the end-face metal is YW-15 alloy, the NR/BR composites have the best dispersibility, the most robust tensile tear performance, the best wet-skid resistance, and minor rolling resistance. When the end face metal is the other three alloys, the physical and mechanical properties of the NR/BR composites are reduced to different extents. In this paper, starting from the actual working conditions, considering both abrasive wear and corrosive wear, the friction and wear between the rubber compound and the four kinds of metals commonly used on the end face of the internal mixer are studied. The metal that has little effect on the performance of the rubber compound and is the most wear-resistant was found. This paper is of great significance for improving production efficiency and prolonging the life of the internal mixer.
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van der Steen, R., I. Lopez et H. Nijmeijer. « Experimental and numerical study of friction and .giffness characteristics of small rolling tires ». Tire Science and Technology 39, no 1 (1 mars 2011) : 5–19. http://dx.doi.org/10.2346/1.3555134.
Texte intégralRésumé :
Abstract Virtual testing is nowadays the standard in the design process of new tires. Besides modeling the static response of the tire itself, the dynamics of a rolling tire in contact with the road needs to be incorporated. Due to the uncontrollable environmental conditions and the complex structure of the tires, it is advantageous to use small-scale testing under more controlled conditions. Experimental characterization of frictional properties of rubber compounds is, however, limited due to the necessity of complex measurement systems. In this paper a commercially available laboratory abrasion and skid tester is used to ide.gify both friction and .giffness characteristics of the same rubber compound. The obtained friction properties are implemented in a finite element model of the setup, and different validation steps are presented. Finally, a steady-state transport approach is used to efficiently compute a steady-state solution, which is compared with the experimental results. The numerical results show a good qualitative agreement with the experimental results.
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Wang, Meng-Jiao, et Yakov Kutsovsky. « Effect of Fillers on Wet Skid Resistance of Tires. Part I : Water Lubrication Vs. Filler-Elastomer Interactions ». Rubber Chemistry and Technology 81, no 4 (1 septembre 2008) : 552–75. http://dx.doi.org/10.5254/1.3548220.
Texte intégralRésumé :
Abstract From results of testing materials using a new filler, it was recognized that the wet skid resistance of tires is determined not only by dynamic properties of the tread compounds, but also by elastohydrodynamic lubrication, especially on the micro scale. By reviewing the basic concepts of friction under dry and wet conditions, and friction coefficients of possible model materials that are at the worn surface of tire tread compounds and road surface, it is inferred that after skid testing under wet conditions, the top skin of the worn surface contains some bare silica for silica-filled compounds, but the carbon black aggregates remain covered by rubber film. This inference is supported by measuring the surface energies of the fillers, analyzing the properties of filled vulcanizates, and direct investigation of worn surface of the compounds after skid test by AFM. The different surface compositions between silica- and carbon black-filled vulcanizates would lead to different effects on micro-elastohydrodynamic lubrication, hence wet skid resistance, which will be the topic of next report of this study.
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Jantaramaha, Jakkrit, Chanchira Jubsilp et Sarawut Rimdusit. « Thermal and Mechanical Properties of Acrylonitrile-Butadiene Rubber Modified Polybenzoxazine as Frictional Materials ». Key Engineering Materials 659 (août 2015) : 511–15. http://dx.doi.org/10.4028/www.scientific.net/kem.659.511.
Texte intégralRésumé :
Frictional composites based on polybenzoxazine (PBA-a) and acrylonitrile-butadiene rubber (NBR) are developed in this study. Mechanical, thermal and tribological properties of the PBA-a/NBR composites at 0, 2, 5, 10 and 15wt% of NBR particle contents are evaluated. Curing behaviors of the NBR-benzoxazine molding compounds are examined by differential scanning calorimetry to show an exothermic peak of about 222°C compared with that of the benzoxazine resin, i.e. 232°C suggesting curing acceleration of the benzoxazine resin due to the presence of the NBR particles. The storage modulus of the NBR-filled PBA-a is observed to systematically decrease from 5.2 GPa of the neat PBA-a to 2.8 GPa with an addition of 15wt% of the rubber particles. Glass transition temperature (Tg) of the composites evaluated by dynamic mechanical analysis increases with increasing of NBR particle contents, i.e. from 172°C for PBA-a to 186°C for PBA-a/15wt% NBR. Furthermore, the friction coefficients of the composites with 2wt% NBR are determined to be 0.603 for static type and 0.528 for kinetic type. Those values are improved from the value of 0.597 and 0.475 for unmodified polybenzoxazine, respectively. Therefore, the obtained outstanding properties, i.e. storage modulus, glass transition temperature and friction coefficient make the polybenzoxazine composites highly attractive to be utilized as friction materials.
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Kawasaki, S., T. Tada et B. N. J. Persson. « Adhesion and friction between glass and rubber in the dry state and in water : role of contact hydrophobicity ». Soft Matter 14, no 26 (2018) : 5428–41. http://dx.doi.org/10.1039/c8sm00847g.
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KUNIZAWA, Tetsuya, Takeru KONDOH et Qing-Qing NI. « Viscoelastic Properties at High Frequency and Wet Friction Behaviour of Carbon Black and Silica Filled Rubber Compounds ». Transactions of the Japan Society of Mechanical Engineers Series A 73, no 731 (2007) : 775–81. http://dx.doi.org/10.1299/kikaia.73.775.
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Jennissen, J. « Highly Efficient Mixing with Tangential Internal Mixers ». International Polymer Science and Technology 44, no 3 (mars 2017) : 1–6. http://dx.doi.org/10.1177/0307174x1704400301.
Texte intégralRésumé :
Tangential internal mixers have been used successfully for over 100 years to process rubber compounds. Continuous development of the mixer has enabled the mixing process to be made ever more effective. The present article describes an often unexploited potential in terms of process engineering. By deliberately adjusting friction and the position of the rotors, further potential can be leveraged at different mixing stages. This additional function can be retrofitted on to existing lines at reasonable cost. Modern multi-layer power train concepts also help to reduce operating costs for the mixing line.
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Heinz, M., et K. A. Grosch. « A Laboratory Method to Comprehensively Evaluate Abrasion, Traction and Rolling Resistance of Tire Tread Compounds ». Rubber Chemistry and Technology 80, no 4 (1 septembre 2007) : 580–607. http://dx.doi.org/10.5254/1.3548182.
Texte intégralRésumé :
Abstract A laboratory test method has been developed which allows the evaluation of diverse properties of tire tread compounds on the same sample. The laboratory test instrument consists of a rotating abrasive disk against which a rubber sample wheel runs under a given load, slip angle and speed. All three force components acting on the wheel during the tests are recorded. By changing the variable values over a wide range practically all severities encountered in tire wear are covered. The well-known fact that compound ratings depend on the road testing conditions is verified. Most compounds are only significantly distinguishable against a control over a limited range of testing conditions. Using a road test simulation computer program based on the laboratory data shows that not only ratings correspond to practical experience but also calculated absolute tire life times do. Tests on surfaces of different coarseness and sharpness indicate that sharp coarse surfaces give the best results with road tests, which of necessity are mostly carried out on public roads of differing constitution. The abrasive surface can be wetted with water at different temperatures and hence either the friction force at a locked wheel or the side force at a slipping wheel can be measured over a wide range of temperatures and speeds. At small slip angles the side force is dominated by dynamic cornering stiffness of the compound, at large slip angles by the friction coefficient. In this case, too, good correlations to road experience exist over a limited range of testing conditions. Low water temperatures and low slip speed settings in the laboratory produce side force ratings, which correlate closely with ABS braking on the road High and higher slip speeds give ratings in close agreement with locked wheel braking on the road. A heatable/coolable disk enables traction measurements on ice and newly abrasion measurements on surfaces at elevated surface temperature. Ice surface temperatures between −5 °C and −25 °C are possible. Friction measurements show that the difference in compound rating between summer and winter compounds is maintained over the whole temperature range. New investigations show not only a differentiation between different winter tire treads qualities but also an excellent correlation between tire and laboratory results. As a new topic side force measurements on dry surfaces highlight the correlation to dry handling of tires. The tire tread compound contributes to this performance through its shear stiffness and its friction coefficient. The shear stiffness contributes to the response of the tire in directional changes. The friction coefficient determines the maximum force, which can be transmitted. A simple operation possibility for evaluation of determined side forces is demonstrated. In addition to antecedent investigations the rolling resistance of the rubber wheel can be measured over a range of loads and speeds with the slip angle set at zero. Again for these new results good correlations are achieved with practical experience. In particular, the dependence of the rolling resistance on the velocity and loads are pointed out. Ultimately a good correlation between tire test and laboratory test results was demonstrated.
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Liarte, Elias, Valentina Zambrano, Leticia A. Gracia, José Ignacio Amor, Marcos Borro et Belén Hernández-Gascón. « Demoulding process assessment of elastomers in micro-textured moulds ». Open Research Europe 1 (24 février 2022) : 120. http://dx.doi.org/10.12688/openreseurope.13716.2.
Texte intégralRésumé :
Background: Micro-texturing is an increasingly used technique that aims at improving the functional behaviour of components during their useful life, and it is applied in different industrial manufacturing processes for different purposes, such as reducing friction on dynamic rubber seals for pneumatic equipment, among others. Micro-texturing is produced on polymer components by transfer from the mould and might critically increase the adhesion and friction between the moulded rubber part with the mould, provoking issues during demoulding, both on the mould itself and on the rubber part. The mould design, the coating release agent applied to the mould surface, and the operational parameters of the moulding/demoulding process, are fundamental aspects to avoid problems and guarantee a correct texture transfer during the demoulding process. Methods: In this work, the lack of knowledge about demoulding processes was addressed with an in-house test rig and a robust experimental procedure to measure demoulding forces (DFs) as well as the final quality of the moulded part, between thermoset polymers and moulds. After the characterization of several Sol-Gel coating formulations (inorganic; hybrid) the influence of several parameters was analysed experimentally, i.e.: Sol-Gel efficiency, texture effects, pattern geometry, roughness and material compound. Results: The results obtained from the experimental studies revealed that texture depth is the most critical geometrical parameter, showing high scatter among the selected compounds. Finally, the experimental results were used to compute a model through reduced order modelling (ROM) technique for the prediction of DFs. Conclusions: The characterization of DFs in a laboratory, with a specific device operated by a universal testing machine (UTM), provided valuable information that allows a fast and optimized introduction of texturing in rubber components. Selection of a novel Sol-Gel coating and the use of the ROM technique contributed to speed up implementation for mass production.
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Liarte, Elias, Valentina Zambrano, Leticia A. Gracia, José Ignacio Amor, Marcos Borro et Belén Hernández-Gascón. « Demoulding process assessment of elastomers in micro-textured moulds ». Open Research Europe 1 (6 octobre 2021) : 120. http://dx.doi.org/10.12688/openreseurope.13716.1.
Texte intégralRésumé :
Background: Micro-texturing is an increasingly used technique that aims at improving the functional behaviour of components during their useful life, and it is applied in different industrial manufacturing processes for different purposes, such as reducing friction on dynamic rubber seals for pneumatic equipment, among others. Micro-texturing is produced on polymer components by transfer from the mould and might critically increase the adhesion and friction between the moulded rubber part with the mould, provoking issues during demoulding, both on the mould itself and on the rubber part. The mould design, the coating release agent applied to the mould surface, and the operational parameters of the moulding/demoulding process, are fundamental aspects to avoid problems and guarantee a correct texture transfer during the demoulding process. Methods: In this work, the lack of knowledge about demoulding processes was addressed with an in-house test rig and a robust experimental procedure to measure demoulding forces (DFs) as well as the final quality of the moulded part, between thermoset polymers and moulds. After the characterization of several Sol-Gel coating formulations (inorganic; hybrid) the influence of several parameters was analysed experimentally, i.e.: Sol-Gel efficiency, texture effects, pattern geometry, roughness and material compound. Results: The results obtained from the experimental studies revealed that texture depth is the most critical geometrical parameter, showing high scatter among the selected compounds. Finally, the experimental results were used to compute a model through reduced order modelling (ROM) technique for the prediction of DFs. Conclusions: The characterization of DFs in a laboratory, with a specific device operated by a universal testing machine (UTM), provided valuable information that allows a fast and optimized introduction of texturing in rubber components. Selection of a novel Sol-Gel coating and the use of the ROM technique contributed to speed up implementation for mass production.