• Journal of Adhesion and Interface
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• v.3 no.3
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• pp.1-6
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• 2002

We invested which is major one in rubber materials design factors affecting on noise and showed the design guide for low noise tire development in this study. Tire noise and impact noise for rubber sheets were tested at anechoic room. Hardness, tensile and dynamic mechanical properties were also measured using the rubber sheets. A major design factor of rubber materials affecting on the tire noise was hardness or 300% modulus. There was also positive correlation between two properties. Therefore, designing rubber materials to have low hardness or 300% modulus can reduce noise.

• Journal of the Earthquake Engineering Society of Korea
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• v.6 no.4
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• pp.39-49
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• 2002

In this paper, the characteristics of RB(rubber bearing) were studied by various prototype tests on RB with low hardness rubber. The characteristics of RB were tested on displacements, repeated cycles, frequencies, vertical pressures, temperature, vertical stiffness and the capability of shear deformation. The prototype test showed that the displacement and vertical pressures were the most governing factors influencing on characteristics of RB. The effective stiffness and equivalent damping of RB showed small increment in high frequency range. After the repeated cyclic test with 50's cycles, the effective stiffness and equivalent damping of RB were almost constant compared with those of the 1st cycles due to low hysteretic damping. The shear modulus of RB was reduced after large deformation, and this value of RB was partly recovered after 40 days. Finally, the shear failure test of RB was conducted, the prototype was failed over 490% of shear strain, and real size RB was failed over 430% of shear strain.

• 한국기계연구소 소보
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• s.13
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• pp.27-43
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• 1984

In order to obtain the high resilience, low compression set and less of hardness change in the wiper blade rubber, vulcanization system and receipes must be controlled. To improve the above the above Physical properties, the system should be taken as follows. i) peroxide vulcanization system and sulfur vulcanization system. ii) rubber having more cis-form than trans-form. iii) moderate particle size cabon black. v) usage of other improvement agent. The rubber blade with 4.4% compression set, 76% resilience, Hs 0 $\pm$ 2 hardness change could be abtained through vulcanization system, In addition, the surface of wiper blade must be treated by chemically and physically to minimize for the skid and friction.

• Structural Engineering and Mechanics
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• v.50 no.1
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• pp.89-103
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• 2014

According to experimental studies made so far, design formula of shear characteristics suggested by ISO 22762 and JEAG 4614, representative design code for Lead Rubber Bearing(LRB) shows dependence caused by changes in compressive stress. Especially, in the case of atypical special structure, such as a nuclear power structure, placement of seismic isolation bearing is more limited compared to that of existing structures and design compressive stress is various in sizes. As a result, there is a difference between design factor and real behavior with regards to shear characteristics of base isolation device, depending on compressive stress. In this study, a full-scale low hardness device of LRB, representative base isolation device was manufactured, analyzed, and then evaluated through an experiment on shear characteristics related to various compressive stresses. With design compressive stress of the full-scale LRB (13MPa) being a basis, changes in shear characteristics were analyzed for compressive stress of 5 MPa, 10 MPa, 13 MPa, 15 MPa, and 20 MPa based on characteristics test specified by ISO 22762:2010 and based on the test result, a regression analysis was made to offer an empirical formula. With application of proposed design formula which reflected the existing design formula and empirical formula, trend of horizontal characteristics was analyzed.

• Elastomers and Composites
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• v.53 no.2
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• pp.80-85
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• 2018

Chloro isobutylene isoprene rubber (CIIR) and ethylene propylene diene monomer (EPDM) compounded with other formulation chemicals, depending on the polymer blend, were prepared by mechanical mixing. After manufacturing the rubber vulcanizate by compression molding with a hot press, the mechanical and thermal properties including thermal conductivity, rebound resilience of the CIIR/EPDM blends were measured. As the EPDM rubber content increased, hardness and tension set showed a tendency to increase. Pure CIIR exhibited the lowest tensile strength; however, tensile strength increased with loading of EPDM rubber. On the other hand, in CIIR rubber, which is usually a low-rebound elastomer owing to a high damping effect, rebound resilience exhibited an increasing trend as the content of EPDM rubber increased. As the EPDM rubber content increased, thermal stability was improved due to reduction of decomposition rate in the rubber region of the blend vulcanizate.

• Journal of the Korean Graphic Arts Communication Society
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• v.18 no.2
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• pp.83-101
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• 2000

In this experiment butadiene rubber(BR)/acrylonitrile butadiene rubber(NBR) blends was prepared and then the applicability of BR/NBR blends as printing rubber roller was examined. With the aid of open 2-roll mill, BR, NBR and another chemical additives were compounded. Then rubber vulcanizates were manufactured by hot press and maximum torque, Mooney viscosity, mechanical properties and oil resistance of the test specimens were measured. With prolonged oil aged treating time, BR/NBR blends became soft and so the hardness of blends decreased. It could be explained by the swelling of rubber matrix with oil penetration in to rubber molecules. The undesirable low value of oil resistance of BR was significantly improved by blending BR with NBR.

• Elastomers and Composites
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• v.39 no.2
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• pp.95-104
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• 2004

New compounds were made using various NR/BR blend ratio and oil content to improve mechanical properties of rubber isolator at low temperature. Mechanical properties were investigated as a function of NR/BR blend ratio and oil content. Hardness and tensile modulus generally increased, but tensile strength and elongation at break decreased with increasing BR content. Hardness, tensile modulus and tensile strength decreased, but elongation at break were nearly the same with increasing oil content. The glass transition temperature of NR and BR were found to be $-50^{\circ}C$ and $-90^{\circ}C$ respectively based on the abrupt drops in storage elastic modulus and peak of loss factor. Two distinct transition temperature were observed in NR/BR blend compounds and each transition point was not affected by blend level indicating incompatible nature of NR/BR blend.

• Elastomers and Composites
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• v.53 no.4
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• pp.202-206
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• 2018

Five solution styrene butadiene rubber/neodymium butadiene rubber (SSBR/NdBR) composites were manufactured using different ratios of SSBR and NdBR. In this study, the composites were reinforced with NdBR and silica to confirm the physical properties of SSBR used for treads of automobile tires and the dispersibility with silica. The morphologies of the rubber composites were observed using field-emission scanning electron microscopy (FE-SEM). The crosslinking behaviors of the composites were tested using a rubber process analyzer (RPA), and the abrasion resistances were tested using a National Bureau of Standards (NBS) abrasion tester. The hardness values, tensile strengths, and cold resistances of the composites were also tested according to ASTM standards. Increased NdBR content yielded composites with excellent crosslinking properties, abrasion resistances, hardnesses, tensile strengths, and cold resistances. The crosslinking point increased due to the double bond in NdBR, thereby increasing the degree of crosslinking in the composites. The NdBR-reinforced composites exhibited excellent abrasion resistances, which is explained as follows. In SSBR, a breakage is permanent because a resonance structure between styrene and SSBR forms when the molecular backbone is broken during the abrasion process. However, NdBR forms an additional crosslink due to the breakdown of the molecular backbone and high reactivity of the radicals produced. In addition, the low glass transition temperature (Tg) of NdBR provided the rubber composites with excellent cold resistances.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.160-162
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• 2017

When rubber elastomer has contact with fuel, since the component and additive having low molecular weight can flow out, the physical properties of both elastomer and fuel could be hindered. In order to predict the life of the rubber elastomer, this study is to determine the change of weight, thickness, hardness, strain, and compression set as mechanical properties of the sealant rubber O-ring, which was dependent on volume, temperature, and storage time of the contacted fuel. We also determined purity of fuel via GC analysis and measured gross heat of combution. The results could be used as a reference to evaluate the life of the rubber elastomer.

• Journal of Welding and Joining
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• v.16 no.1
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• pp.125-133
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• 1998

The effect of volume fraction of Cr carbide phase (Cr CVF) on the low stress abrasion resistance in the chromium-carbide-type high Cr white iron hardfacing weld deposits has been investigated. In order to examine Cr CVF, a series of alloys with varying Cr CVF by changing chromium and carbon contents and the ratio of Cr/C were employed. The alloys were deposited once or twice on a mild steel plate using the self-shielding flux cored arc welding process. The low stress abrasion resistance of the alloys against sands was measured by the Dry Sand/Rubber Wheel Abrasion Test (RWAT). It was shown that hardness and abrasion resistance increased with increasing Cr CVF within the whole test range (Cr CVF : 0.23-0.64). Both primary Cr carbide and eutectic Cr carbide were particularly effective in resisting wear due to their high hardness.