• 대한정형도수물리치료학회지
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• 제15권1호
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• pp.9-21
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• 2009

Purpose : To know how much weight bearing on left and right leg on 14 different positions. The second is to know how about different the weight bearing ratio on same positions of ages group. Methods : The third is to know how about changes the weight bearing ration between exercise group and non exercise group. The group of age is divided 20s, 30s, 40s, 50s, over the 60 years. The subjects are 93 males(44), females(49). Results : The ordering of ratio of weight bearing on one side leg is as follows: The position of the highest weight bearing ratio is one leg standing with the other leg on chair(right 0.82, left 0.81) and the position of lowest weight bearing ratio is hooklying with natural leg position(both legs 0.08). There are statistically significant difference between right and left leg of weight bearing ratio on the 6 positions among the 14 positions. As for the ages, there are statistically significant difference on 5 different positions of 20 ages body weight bearing ratio between right and left leg. But as for the 50 ages there are no statistically significant difference on all of 14 positions between right and left leg body weight bearing. As for the exercise group there are statistically significant difference on only one position of one leg standing with the other leg on chair between right and left weight bearing ratio. But as for non exercise group there are statistically significant difference on 4 positions between right and left weight bearing ratio. Conclusion : When the therapist exercise with patient's always considerate of patient's position and weight bearing ratio.

• Tribology and Lubricants
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• 제37권4호
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• pp.117-124
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• 2021

In this study, we perform a 3D CFD conjugate analysis according to the shape of the foil ramp of the air foil thrust bearing, analyze the flow characteristics inside the bearing, and compare the results corresponding to the two shapes. Air has a lower viscosity than lubricating oil. Therefore, the thrust runner of the bearing must rotate at high speed to support the load. The gap between thrust runner and foil is significantly smaller than that of the oil bearing. Hence, it is crucial to analyze the complex flow characteristics inside the bearing to predict the complex flow inside the bearing and performance of the bearing. In addition, flow characteristics may appear differently depending on the ramp shape of the bearing foil, which may affect bearing performance. In this study, we numerically analyze the main flow path of air flowing into the bearing and the secondary flow path used for cooling the bearing using the commercial CFD software ANSYS CFX and compare the flow characteristics for straight and curved foil ramp shapes. Notably, there is a difference in the speed of the flowing air according to the shape of the ramp, which affects the bearing performance.

• Journal of the Korean Wood Science and Technology
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• 제50권1호
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• pp.1-11
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• 2022

To evaluate the bearing strength of red pine cross-laminated timber (CLT) with self-tapping screw (STS), which is widely used as a fastener for connection in CLT building, the bearing test was conducted. Accoring to the STS's diameters (8, 10, 12 mm), the bearing test specimens with half hole were manufactured. Bearing strength was compared and reviewed in consideration of the configuration in STS and the loading direction to the grain of red pine. As a result of the bearing test on the STS's diameter, the yield bearing load increases as the larger diameter of the STS in all directions of the red pine. The bearing strength of the thread part (thread + tip) was higher than the shank part (shank + shank cutter). In compared with the directions to the grain of red pine, the bearing strength of the cross section parallel to the loading direction was the highest, and the tangent section was the lowest bearing strength. The average bearing strength of the loading direction in parallel to the grain was 23.43 MPa, which was about 45% higher than the average 16.16 MPa in perpendicular to the grain. The predicted bearing strength calculated by Eurocode (EN) and Korean Building Code (KBC)'s equation was lower than the experimental value. It is nessesary to propose the new equations of bearing strength reflected the configuration information of STS.

• 전기학회논문지P
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• 제60권2호
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• pp.82-90
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• 2011

The small precision spindle motors in the high value-added products including the visible home appliances such as DLP projector require not only the energy conversion devices but also high efficiency, low vibration and sound operation. However, the spindle motors using the conventional ball bearing and sintered porous metal bearing have following problems, respectively: the vibration by the irregularity of balls and the short motor life cycle by the ball's abrasion and higher sound noises by dry contact between shaft and sleeve. In this paper, it is proposed that the spindle motor with a fluid dynamic bearing is suitable for the motor to drive the color wheel of the DLP(digital lightening processor) in the visible home appliances. The proposed spindle motor is composed of the fluid dynamic bearing with both the radial force and the thrust force. The fluid dynamic bearing is solved by the finite element analysis of the mechanical field with the Reynolds equations. The magnetic part of spindle motor, which is a type of Brushless DC Motor, is designed by the electro-magnetic field analysis coupled with the Maxwell equation. And the load capacity and the friction loss of fluid dynamic bearing are analyzed to bearing clearance variation by the fabrication error in designed motor. The design of the proposed motor is implemented by the load torque caused by the eccentricity and the unbalance of the fluid dynamic bearing when the motors are fabricated in error. The prototype of the motor with the fluid dynamic bearing is manufactured, and experiment results show the vibration, sound, and phase current at no load and color wheel load of the motors in comparison. The high performance characteristics with the low vibration, the low acoustic noise and the optimal mechanical structure are verified by the experimental results.

• 대한족부족관절학회지
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• 제4권1호
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• pp.5-12
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• 2000

Purpose: The purpose of this study is to assess the amount of changes in the foot size on weight bearing in adult women, which might help in choosing an appropriate size of the shoes. Materials and Methods: The authors measured the length and width of the feet of 200 healthy women on weight bearing and non-weight bearing, and the size of the shoes they wore. Results: Foot length and width differences between right and left sides were 2.53 mm and 2.16 mm respectively on non-weight bearing, and 2.47 mm and 1.77 mm respectively on weight bearing. Foot length and width increased by 2.89% and 7.50% respectively on weight bearing than those on non-weight bearing. Shoe width was 6.82% longer and 9.54% narrower than the weight bearing foot size. There were 25 women who had shoe-related foot pain, all of them wore shoes that were 13.01 % or more narrower than the weight bearing foot width. Foot pain was significantly correlated with the shoe-foot width difference(p=0.0001). Conclusion: The foot size was increased by 2.89% in length and 7.50% in width with weight bearing. The width of their shoes was narrower. than the weight bearing foot width. Shoe-related foot pain was correlated with the foot-shoe width difference.

• 한국지반신소재학회논문집
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• 제13권2호
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• pp.41-47
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• 2014

헬리컬 파일은 나선형 원판이 부착된 철제 축과 나선형 원판이 모두 지지력을 발휘하기 때문에 지지력을 예측하는데 있어 기존의 일반적인 말뚝과는 다른 다양한 산정법이 적용되고 있다. 대표적으로 Individual bearing method, Cylindrical shear method, Torque correlation method가 사용되고 있다. 본 연구에서는 국내 지반에 시공된 중소구경 헬리컬 파일의 지지력을 예측하는데 있어 적절한 지지력 산정 방법을 검토하기 위해 연계논문의 현장 정재하시험에서 측정된 지지력과 3가지 방법으로 예측한 지지력을 비교 분석하였다. 비교 결과, 실측 지지력이 Individual bearing method와 Cylindrical shear method로 예측한 지지력의 최대값과 최소값 사이에 위치함을 확인하였으며, 상대적으로 Torque correlation method으로 예측한 결과가 실측지지력과 가장 유사함을 보였다.

• 한국자동차공학회논문집
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• 제10권3호
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• pp.44-50
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• 2002

The connecting rod big-end bearing is one of the most heavily loaded components of the lubrication system of high-speed combustion engines. The supply oil flow has to pass to the main bearing and the rotating crankshaft before entering the connecting rod bearing. It is common knowledge that the centrifugal forces due to the crankshaft rotation influence the oil flow to connecting rod bearing through the oil supply bore, especially, when the oil supply system to the connecting rod bearing has a 180$^{\circ}$circumferential groove via a single drilling in the crankshaft. In this case, it should be confirmed that the groove oil pressure in the main bearing is sufficient to overcome these centrifugal forces. For the purpose, the dynamic oil pressure before entering oil supply bore to the connecting rod bearing was measured instead of averaged oil pressure in main gallery. Experimental test results show that the dynamic oil pressure in the oil groove was more useful than that of main gallery. And it was also found that the oil pressure fluctuation in the groove was sensitively affected by the reduction of the main bearing clearance.

• Tribology and Lubricants
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• 제12권4호
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• pp.28-34
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• 1996

The lubrication characteristics of high-speed ball bearings have been investigated empirically using 45mm bore split inner ring ball bearings employed in small industrial gas turbine engines with oil-jet lubrication method. For the close structural simulation, experiments carried out with bearing mounting supports of real engines, such as bearing housings and oil nozzle assemblies with squeeze film dampers. Thus the results of tests can be directly applied to the design and the development of gas turbine engines. Testing was done by varying operating speeds, axial load on bearings, and lubricant flow rates. During testing, the temperature of bearing at outer-ring face, the power consumption of the driving motor, and the rotating resistance of the bearing were measured. From this study, the representative factors for lubrication characteristics at high speed was found, and the most important one was not operating speed but axial load up to 1.95 million dmN speed and 2969 N axial load. Furthermore, the detailed variation of the rotational resistance of the bearing could be visualized by measuring the change of the radial load under the bearing supports. The rotational resistance consists of the frictional resistance and the bearing-cavity oil resistance.

• The Journal of Korean Physical Therapy
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• 제32권1호
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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.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.1697-1702
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• 2010

It has been recognized for decades that the spherical bearing which is sliding on curved surface in the intrinsic behavior is optimized for the railway bridge requiring a large slope deflection. However, the spherical bearing is easily corrosived at the PSC girder bridge which is exposed to the outside so the normal function of bridge bearing is not fulfilled fully. It is common that the corrosion is happened at the operating plate of steel bridge bearing and generally it is necessary to replace the bridge bearing after 20~25 years. Accordingly, It costs multi billion dollars for maintenance each year and the necessity of improvement become a issue. Korea Rail Network Authority(KR) suggested to apply the Elastomeric bearing instead of Spherical bearing through the task of construction site of 2006. But the normal Elastomeric bearing is optimized for the Highway bridge so it needs the special consideration to satisfy each design condition required by railway bridge. As the result of examination of Elastomeric bearing at the railway bridge construction site, the stress is decreased by effective dispersion of earthquakes and the maintenance fee is also decreased.