• Journal of the Computational Structural Engineering Institute of Korea
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• v.36 no.3
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• pp.165-171
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• 2023

The rotary joint connecting the upper and lower structures of construction machinery and special vehicles transmits hydraulic pressure as the shaft and housing rotate, and multiple seals are assembled to prevent oil leakage into the oil flow channel. Because the seal material is rigid and difficult to assemble, we sought a method to assemble it after cutting. The shapes of the cutting surface are L-shaped and / shaped, and the leakage standard when hydraulic pressure is applied is the contact pressure generated on the cutting surface. The structure and material of the seal are composed of a double elastomer, and nonlinear contact structural analysis is performed when only the high-rigidity PE material is cut. Studies have shown that the shorter the cutting length, the better the leakage prevention and the higher the possibility of leakage to the bottom surface where NBR and PE come into contact rather than the top surface where the PE and the housing come into contact.

• Journal of Aerospace System Engineering
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• v.8 no.1
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• pp.24-29
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• 2014

Turbopump is typically an assembly of rotors and casings, and there are a number of joints between them. Every joint should be leak-proof, so there is always a seal to accomplish the goal. Among various seals, metal seals are advantageous in that they are robust at high pressure, and at wide range of temperature. On the other hand, they require very high tightening forces, so that flanges, bolts and nuts should be carefully designed to ensure structural integrity and to prevent detrimental yielding of components. In this study, flange joints using conical seals made of stainless steel, solid flat metal seals made of copper and metal C-seals made of Inconel 718 were structurally designed and analyzed, considering both initial tightening and operating conditions.

• Journal of the Korean Institute of Gas
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• v.15 no.6
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• pp.34-37
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• 2011

This paper presents sealing contact stress and deformation behaviors of an elastomeric contact seal for a pipe connection. In this study, a pipe connection is used by a joint nut and an elastomeric contact seal with a sealing interference of 0.2~0.5mm. A sealing interference in which compresses an elastomeric contact seal is generated by fastening a joint nut between two pipes. The FEM computed results show that the contact normal stress of contact model 1 with an inclined sealing surface is 1.5~1.75 times high in compared with that of contact model 2 with a parallel sealing surface. This indicates that the sealing contact surface recommends a wedge contact mode between two pipe connections for a high sealing compression stress.

• Tribology and Lubricants
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• v.26 no.1
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• pp.61-67
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• 2010

The purpose of this paper is to study and analyze the failure examples on tribological characteristics of an automotive steering system. In this failure study, the grease leakage may stick leaked grease, dust, and wear particles between pinion and rack gears in mechanical steering system. In the case of seal failures such as a rod seal, o-ring and oil seals, the gear box and oil pump do not operate properly due to lack of oils. This means that oil pump does not supply a working fluid and produce a normal oil pressure of the steering system. This leads to leak a working fluid from the seals and produce a wear between pinion and rack gears. Especially, the leaked oil is usually mixed with internal wear particles and foreign dust/fine sands. Thus no leakage of working oils is very important design concepts, which is strongly related to the sealing components and smoothly operating of the mechanical friction parts of power steering system.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.234-235
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• 2017

The bonding of the asphalt-based waterproof sheet is carried out in such a manner that the sheet and the sheet are adhered together and the lower adhesive layer of one sheet is adhered to the upper film layer of the other sheet, and the asphalt layer and the PE or HDPE film layer are bonded. When the joints are formed in the form of junctions between heterogeneous materials and exposed to the concrete joint movements and other deteriorating factors, the integrity of the joints can deteriorate and problems such as lifting and peeling off of the joints can occur. Therefore, this study was carried out to prevent unstable joint adhesion of the asphalt compound and film layer and to prevent defects in the adhesion between self - adhesive waterproof sheets. The self-adhesive waterproof sheet of this study can maximize bond stability by inducing bond between asphalt compounds during sheet-to-sheet bonding, thereby improving bonding strength.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.11a
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• pp.165-166
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• 2014

The Composite waterproofing began to rise gradually 2000s in domestic. However, the sheet-membrane composite waterproofing method also acts as an abutment vulnerability that was a problem in a single method, and had the problem of damage to the formation of leakage paths. The existing non-overlap method, through vigorous research abutting sheet shall or could be developed to improve the seal performance of this method with the I-type joint coating material. Nevertheless, it has an integral top coat paint membrane and a sheet abutment limitation, damage to the upper membrane is damaged junction coating membranes has been generated. In this study, a method that has a layer of insulation on the joint bond breaker concept development, and to determine the physical properties with insulated joints to determine the breaking off of the upper joint is damaged coating membrane and tensile performance.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.11
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• pp.1055-1064
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• 2017

Since a device such as a rocket motor requires very high reliability, a reasonable reliability design process is essential. However, Korea has implemented a design method for applying a safety factor to each component. In classic reliability analysis, input variables such as mean and standard deviation, used in the limit state function, are treated as deterministic values. Because the mean and standard deviation are determined by a small amount of data, this approach could lead to inaccurate results. In this study, reliability analysis is performed for bolted joints and o-ring seals, and the Bayesian approach is used to statistically estimate the input variables. The estimated variables and failure probability, calculated by the reliability analysis, are derived in the form of probability distributions.

• Journal of Aerospace System Engineering
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• v.16 no.4
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• pp.53-59
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• 2022

Static seals are used to seal high temperature gas and cryogenic fluid under high pressure, at interfaces between liquid rocket engine components such as combustion chamber, turbopump, gas generator, valves, etc. As thermal expansion and contraction at assembly interfaces cause undesirable leakage under cryogenic and high temperature environments, static seals applied for sealing of joint interfaces without relative motion should be designed properly. The additional function of rotation at the sealing face is also required for static seals, when the spherical flange is used for improvement of assembly at misalignment interfaces. In this study, structural analysis and leak tightness test of simulating test rig for several important interfaces are performed, to verify structural integrity of static seals.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.283-288
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• 2011

The spherical flange was designed to apply to a cryogenic high pressure pipe of the Liquid Rocket Engine. It is designed that the spherical flange is able to be assembled and kept airtight upto $2.5^{\circ}$ of the axial misalignment between the combined components. It increases the degree of freedom of the engine assembly. The spherical flange is composed of a ball and socket joint, a metal seal and spherical type bolts, washers. The prototype was verified by leak test at the room temperature and the cryogenic temperature. Additionally the strength test and the destructive test were performed at the room temperature.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.3
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• pp.64-69
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• 2011

The spherical flange was designed to apply to a cryogenic high pressure pipe of a liquid rocket engine. It is designed that the spherical flange is able to be assembled and kept airtight up to $2.5^{\circ}$ of the axial misalignment between the combined components. It increases the degree of freedom of the engine assembly. The spherical flange is composed of a ball and socket joint, a metal seal, spherical type bolts and washers. The prototype was verified by leak test at the room temperature and the cryogenic temperature. Additionally the strength test and the destructive test were performed at the room temperature.