• 한국자동차공학회논문집
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• 제21권5호
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• pp.104-112
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• 2013

This study investigates the structural analysis result with vibration and fatigue on 3 kinds of bicycle saddle models. When the static load applies on the upper plane of model, maximum stress becomes within the allowable stress in case of model 1. As the value of Stress or deformation becomes lower on the order of model types 1, 2 and 3, these models become more stabilized or safer at durability in this order. On the vibration analysis, model type 1 has the maximum stress or deformation more than 5 times by comparing with model type 1 or 2. Model type 1 becomes most excellent on vibration durability. As maximum displacement due to vibration happens in case of model type 3, it becomes unstabilized. But the stresses of model types 1, 2 and 3 become within the allowable stress and these models are considered to be safe. At the status of the severest fatigue load, model type 3 becomes safer than model type 1 or 2. This study result is applied with the design of safe bicycle saddle and it can be useful to improve the durability by predicting prevention against the deformation due to its vibration and fatigue.

• 센서학회지
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• 제27권4호
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• pp.242-248
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• 2018

Bicycle fittings have been used to ride bicycles comfortably while minimizing non-traumatic injuries. To analyze the cause of non-traumatic injuries, it is necessary to measure the body weight distribution in various biking positions. In this study, a weight distribution measurement system was implemented by installing five weighable devices on the saddle, both pedals, and both handle grips of a bicycle. To measure the body weight applied through the saddle, the structure of a commercial seat post was modified and a load cell was installed inside. Weighable pedals and handle grips were designed using a 3D modeling program and fabricated by employing a 3D printer. The body weight distribution for ten bicycle riders was measured when the two pedals were aligned horizontally and vertically. Experimental results showed that the body weight distribution varied significantly depending on human body shape, even after the bicycle fitting was completed. The difference between the body weight measured by the proposed system and a commercial scale was less than 3 %.

• 대한인간공학회:학술대회논문집
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• 대한인간공학회 1993년도 춘계학술대회논문집
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• pp.145-145
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• 1993

In bicycle design, saddle is the major part which effects the subjective comfort of rider. This study examines the correlation between the subjective comfort and elastic body pressure. The elastic body pressure measuring instrument for free-form surface such as saddle is developed by force sensor register, A/D converter and computer. The subjective comfort is measured quantit- atively by 11-point scale method and the elastic body pressure distribution is obtained through 3 different saddles at 4 postures. The pressure distribution is presented by computerized equi- pressure contour. While mean pressure, standard deviation of pressure, maximum pressure are inversely proportional to subjective comfort, the modified saddle-bearing weight which is the surface integral of pressure is directly proportional. Consequently, standard deviation of pressure is most important characteristic which affects variation of subjective comfort.

• 한국디자인학회:학술대회논문집
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• 한국디자인학회 2001년도 Bulletin of The 5th Asian Design Conference International Symposium on Design Science
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• pp.52.2-52
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• 2001

• 한국기계가공학회지
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• 제11권4호
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• pp.72-81
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• 2012

This study investigates structural, fatigue and modal analyses at bicycle suspension seat post. When weight is applied to the saddle, models 1 and 2 have the weakest strength at the part connected with saddle. And model 2 is greater total deformation and equivalent stress than model 1. Among the cases of nonuniform fatigue loads at models 1 and 2, 'SAE bracket history' with the severest change of load becomes most unstable but 'Sample history' becomes most stable. In case of 'Sample history' with the average stress of 0 to $-10^4MPa$ and the amplitude stress of 0 to $10^4MPa$, the possibility of maximum damage becomes 4%. This stress state can be shown with 5 to 7times more than the damage possibility of 'SAE bracket history' or 'SAE transmission'. Model 1 has better impulse relaxation and passenger sensitivity than model 2. The structural result of this study can be effectively utilized with the design of bicycle suspension seat post by investigating prevention and durability against its damage.

• 한국자동차공학회논문집
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• 제20권6호
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• pp.146-155
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• 2012

This study aims to analyze durability by comparing displacement on vibration at driving bicycle frame models of 1, 2, 3 and 4. Among maximum equivalent stresses at 4 kinds of models, model 1 has highest value with 410.39 MPa and becomes 30 times than model 4 with lowest value. The natural frequency number at Model 4 increases more than the other models. Among four models, the number of frequency at model 1 becomes lowest at harmonic vibration with real loading condition. In cases of four kinds of models, the maximum stress is shown near the assembly of rear wheel and the maximum displacement is shown near saddle assembly at this harmonic condition. The structural result about this study can be effectively utilized on the design of bicycle frame by investigating durability and prevention against its damage.

• 한국생산제조학회지
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• 제22권6호
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• pp.969-975
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• 2013

While accelerating, bicycle frames are subject to torsion forces and deformation. In this study, bicycle frame durability was evaluated by using structural, fatigue, and vibration experiments. Three types of models were designed by changing the frame configurations according to the shape and direction of a bicycle frame design. Because maximum equivalent stress was greatest at the saddle and at connected parts in Models 1, 2, and 3, these frame sections were most vulnerable to failure. Model 2 was the least safe, due to the increased total deformation and equivalent stresses in the top tube horizontal to the ground. Based on vibration and fatigue analysis results, Model 2 was also determined to be the least safe frame, because the head tube was placed slightly higher above the seat tube and inclined to $10^{\circ}$. These study results can be utilized in the design of bicycle frames by investigating prevention and durability against damage.

• 한국융합학회논문지
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• 제9권11호
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• pp.363-369
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• 2018

본 연구의 목적은 자전거 안장 높이에 따라 요추부 근 활성도와 산소 소모량의 차이를 알아보기 위해 실시하였다. 근골계 장애가 없는 22명의 건강한 남자가 본 연구에 참여하였다. 대상자들은 3가지 다른 안장 높이로 3분씩 자전거를 탔으며 각 조건 별로 10분의 휴식시간을 가졌다. 표면 근전도는 요추부 근 활성도를 측정하기 위해 사용되었고 산소 소모량은 휴대용 가스 분석기를 사용하여 평가되었다. 연구 결과 내복사근만 유의한 차이가 있었고(p<0.05), 산소 소모량은 높은 안장 높이가 최적 안장 높이와 낮은 안장 높이 보다 유의하게 높게 나타났다(p<0.05). 본 연구는 안장 높이가 건강한 남성의 내복사근 활성도와 산소 소모량에 영향을 미친다고 제안하지만 안장 높이는 요추 안정화 근육에 영향을 미치지는 않았다.

• 한국기계가공학회지
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• 제14권6호
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• pp.84-89
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• 2015

The thickness of a stable and economical frame has been designed in order to reduce costs. Therefore, this study applied structural analysis and vibration analysis based on a comparison of the thicknesses of frames. Four types of frames (1mm, 2mm, 3mm, and 5mm) were modeled on a bicycle frame that has a length of 842mm, a width of 100mm, and a height of 400.5mm, and all of these frames generated the stress and maximum deformation amount in the state and around the saddle. The maximum stress shown was 25.732 MPa in 1mm, 11.79 MPa in 2mm, and 8.2015 MPa in 3mm, and the maximum deformation amount shown was 0.063611mm in 1mm, 0.031978mm in 2mm, and 0.022319mm in 3mm. The natural frequency of the frame thicknesses 1mm, 2mm, and 3mm was estimated as within 270 Hz. The critical frequency of conditions of 3mm was the biggest at 118.1Hz compared with the 3-mm model; thus, 3mm was shown to have the most satisfactory resistance.

• 대한안전경영과학회지
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• 제20권4호
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• pp.1-6
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• 2018

Recently, bicycle has means of effective healthy transportation, and riding the bicycles is considered as popular recreational and sporting activities. Also, the saddle, steering system, driving device and braking device are researched briskly because of consumer's need for driving performance and comfort. Especially, the importance of a cassette responsible for transmission function by transmitting power to the drive shaft through the chain is very focused. The writer conducted structural analysis for the sprocket of each level using the ANSYS widely used for the analysis. Speed shifting performance was enhanced by minimization / simplification of shifting point through a sort of tooth profile of the cassette. By partitioning a clear value type and other shifting point, it has been modified to enable smooth speed-shifting. In addition, as titanium precision forming process, this study studied the molding technique by blanking and dies forging for mass production of the cassette. so it could be expected that the entire drive train would utilize that in the future. The stamping process capability for thin materials for the mass production of the sprockets is applicable to producing automobile parts, so lightweight component production is likely to be possible through that, for the safety of driving.