• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.347-352
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• 2002

Recent trends in the construction of building frame feature the increase use of composite steel concrete members functioning together in what terms of mixed structural systems. One of such systems, RCS(reinforced concrete column and steel beam) system is introduced and closely examined focusing on bearing strength of the composite joint in this paper. The main objective of this study was to develope one of details to increase bearing capacity while bearing failure is one of the two primary modes of failure in RCS system. Local bearing tests with specimens about 1/3 of the actual concrete column size were performed applying uniform load through steel plate with 100$\times$110mm size. Test results show that specimens with the bearing reinforcement detail developed in this study enhanced the bearing strength by 1.71~3.02 compared to concrete cylinder strength.

• Journal of the Korean Society of Safety
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• v.25 no.3
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• pp.1-6
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• 2010

Ball bearings are one of main components that support the rotational shaft in high speed rotary machinery. So, it is very important to detect the incipient faults and fault growth of bearing since the damage and failure of bearing can cause a critical failures or accidents of machinery system. In the past, many researchers mainly performed to detect the bearing fault using traditional method such as wavelet, statistics, envelope etc in vibration signals. But study on the detection technique for bearing fault growth has a little been performed. In this paper, we verified the possibility for monitoring of fault growth and detection of fault size in bearing outer-race by using the envelope powerspectrum and probabilistic density function from measured vibration signals.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.9
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• pp.94-102
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• 2010

The spindle is the main component in machine tools. To develop high speed machine tools, a lot of studies have been carried out for high speed spindle. Bearing is very important part in spindle. The bearing clearance is influenced by shrink fit and thermal expansion during operation. The designer must take into account the reduction of shrink fits. The aims of this study are to grasp the shrink fits and behavior of a bearing which is a deeply connected with fatigue life of bearing and performance of spindle through FEM(Finite Element Method). This paper proposed optimum value of shrink fit considering deformation of spindle and stress of fitting area using design of experiments. Thus, the proposed formula can be used to obtain bearing internal clearance.

• 연구논문집
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• s.33
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• pp.67-79
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• 2003

The life of oilless bearing affects the durability of scroll compressor. The main shaft of the scroll compressor is supported by oiiless bearing. Some of the major parameters which influence the life of oilless bearing are rotational speed, normal load, environment of refrigerant and oil film thickness. The reliability evaluation of oiiless bearing is performed through the acceleration life test for reduction of experimental time and costs. In this study, the experimental and computational investigations were performed to verify the effects of various parameters on the life of oilless bearing. The acceleration factor was achieved with the lubrication analysis between the scroll compressor and the developed reliability tester. the expected life of oilless bearing was guaranteed by reliability evaluation accompanied with the acceleration life test.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1334-1337
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• 1997

A spacecraft attitude control ground hardware simulator development is discussed in the paper. The simulator is called KT/KARI HILSSAT(Hardware-In-the Loop Simulator Single Axis Testbed), and the main structure consists of a single axis bearing and a satellite main body model on the bearing. The single axis tabel as ans experimental hardware simulator that evaluates performance and applicability of a satellite before evolving and/or confirming a mew or and old control logic used in the KOREASAT is developed. Attitude control of spaceraft by using reaction wheel is performed.

• Tribology and Lubricants
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• v.5 no.1
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• pp.69-75
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• 1989

The mobility method of dynamically loaded journal bearings was applied to optimize the lubrication of the main journal bearing of the crank press. The effects of oil viscosity, temperature bearing clearance, length, the existence of the circumferential groove, peak press force, and crank rpm were examined. From the results of the minimum film thickness and the maximum film pressure, some of the factors could be optimized, and the degrees of the beneficial and detrimental effects of the others could be estimated.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.1
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• pp.96-100
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• 2011

The hydrostatic bearings have a relatively small run-out comparing to its shape error by fluid film effect in hydrostatic state as like pneumatic bearing and have a high stiffness, load capacity and damping characteristics. As there is no maintenance and semipermanent in these bearing type, it has been usually adopted as main spindle bearing for grinding machine. In this thesis, to develop hydrostatic bearing for high speed spindle, the cooler setting temperature, bearing clearance and nozzle pressure of belt-driven hydrostatic bearing are investigated. The bearing temperature is decreased, as the cooler setting temperature is lower, nozzle pressure is higher and bearing clearance is wider. The front temperature of bearing is nearly $8^{\circ}C$ higher than the rear one up to 13,000 rpm of spindle revolution. The thermal deflection of X-axis is ${\pm}16\;{\mu}m$ in range of 12,000 rpm-13,000 rpm. Therefore, it is conformed that the built-in motor hydrostatic bearing can be used to high speed spindle.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.112-118
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• 2005

Ball bearings which were fitted between housing and shaft play an important role in rotating shaft system smoothly, Therefore bearing's running accuracy has significant influence on that of rotating machinery. Manufacturing accuracy of bearings as well as that of shaft and housing is main factor to affect bearing running accuracy In this paper, bearing's vibration and fatigue life considering raceway roundness of ball bearing before and after being fitted into housing are theoretically estimated. To perform analysis, a simple three degrees of freedom model was proposed and then these analysis was conducted utilizing the Newton-Raphson iterative method. The results show that vibration magnitude of ball bearing fitted into housing is considerably larger than before assembly, and bearing's theoretical L$_{10}$ fatigue life that ninety percent of the bearing population will endure decreased in about fifty percent.

• The Journal of Korean Physical Therapy
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• v.32 no.1
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• pp.29-33
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• 2020

Purpose: This study examined the effects of the weight-bearing pattern and calcaneal taping on the heel width and plantar pressure in standing. Methods: Fifteen healthy subjects with normal feet participated in this study. The heel width was measured using a digital caliper, and a pedoscan was used to measure the plantar pressure of the rear foot while standing. The participants were instructed to stand in three weight-bearing patterns (anterior, middle, and posterior weight bearing) before and after calcaneal taping. The heel width and plantar pressure were measured three times before and three times after calcaneal taping, with the three weight-bearing patterns applied in random order. A 2 (non-taping vs. taping) × 3 (anterior, middle, posterior weight bearing) two-way repeated ANOVA with a Bonferroni post hoc correction was used to assess the differences in heel width and plantar pressure. Results: The results revealed a significant main effect of the weight-bearing pattern (p<.01), but not of calcaneal taping (p>.05). Greater weight bearing applied to the heel resulted in a significantly increased heel width and planter pressure of the rear foot (p<.01). Conclusion: In standing, a posterior weight-bearing pattern increases the heel width due to side-to-side shifting of the plantar heel pad, which increases the heel plantar pressure. Therefore, to prevent high stress on the heel pad and plantar heel pain, it is important to refrain from posterior weight bearing while standing during the activities of daily living.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.405-406
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• 2002

The main subject of this paper is analyzing the patterns of maximum oil film pressure and the minimum oil film thickness under various pre-conditions of geometric shape as functions of bearing groove and proceeding oil hole in the connecting rod bearing. As the major analytical tool, elastohydrodynamic lubrication analysis has been applied and two-intertwined results of maximum oil film pressure and minimum oil film thickness have been compared and analyzed using EXCITE program. From computed results, the optimal lubrication conditions as geometric shape of bearing groove and the proceeding oil hole have been investigated. This may be useful for the bearing designer as a firm reference.