• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.382-386
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• 2009

The life of a component decreases when it was exposed at the extreme condition. A turbine blade of a turbopump used for a liquid rocket engine is operated under the environment of high temperature and pressure, and experienced high centrifugal force. Thus the durability of the turbopump operated under the these conditions become lower than expected because of the severe fatigue and creep influence. The damage of the turbine being considered the fatigue and the creep influence is estimated to ensure the durability of turbopump turbine. ABAQUS/CAE and MSC.Fatigue are used for the fatigue analysis, and Larson-Miller parameter and robinson's rule are used for the creep analysis. In this paper, comparison and analysis of the fatigue and the creep influence were performed to ensure the life expectancy of turbopump turbine.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.6
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• pp.10-15
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• 2017

The refraction expansion joints have been newly developed by complementing the problems of shock, noise, replaceability, displacement in the direction perpendicular to bridge, vertical difference, which are problems of existing expansion joints. The Refraction expansion joints are characterized by continuous surfaces with small impact and low noise. The behavior of the Refraction expansion joints performs the bridge expansion behavior by rotation of the link. In the rotational behavior of the link, the bolt is the central axis of the behavior. Therefore, it can be said that the durability of the bolt is very important. However, the theoretical and experimental verification of the bolt durability of the Refraction expansion joint is lacking. In this paper, to verify the fatigue durability of the bolt, test specimens with a 300 mm Refraction expansion joint were fabricated. A strain gauge dedicated to the bolt was installed inside the manufactured test specimen bolt. The test method was applied in accordance with KS F 4425. The fatigue durability of the bolts assembled inside the diaphragm expansion joint was confirmed by the repeated fatigue test of 2,000,000 cycles.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.4
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• pp.88-95
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• 2011

In this study, the deformation, stress, vibration, fatigue life and the probability of damage are analyzed at the pedal applied by the force of 300N. The maximum stress at the lower of pedal is shown as 20.801MPa. And the maximum displacement is 0.85mm at the maximum response frequency as 3800Hz. Among the cases of nonuniform fatigue loads, '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 $-10^{5}MPa$ and the amplitude stress of 0 to $10^{5}MPa$, the possibility of maximum damage becomes 0.6%. This stress state can be shown with 5 times more than the damage possibility of 'SAE bracket history' or 'SAE transmission'. The structural result of this study can be effectively improved with the design of pedal by investigating durability against its damage.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.2
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• pp.199-205
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• 2013

Stress and deformation on forklift happened at loading, unloading or moving freight are studied by structural and fatigue analysis in this study. As model 1 as closing type between forks has lower stress and stain than model 2 at opening type, model 1 has more durability than model 2. Among the cases of nonuniform fatigue loads, 'SAE bracket history' with the severest change of load becomes most unstable but 'Sample history' becomes most stable. In case of 'SAE bracket history' with the severest change of load at model 1 and 2, maximum life is shown with Cycle. Minimum damage with 854 at model 2 becomes much higher than model 1. As the gap between forks becomes open, the damage probability becomes higher. The structural result of this study can be effectively utilized with the safe and stable design of forklift by investigating prevention and durability against its damage.

• Journal of the Korea Convergence Society
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• v.6 no.1
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• pp.93-101
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• 2015

As the axle at the vehicle of railway has the important role for safe running, the strength, and impact-proof, safety factor, stress and deformation must be considered. There are the simulation models of 1 and 2 in this study. These models are investigated by performing the convergence technique through the design, the structural and fatigue analyses with CATIA and ANSYS. As the maximum deformation and equivalent stress of model A are lower than those of model B, model A has more durability than model B. The durability to prevent the damage can be investigated by applying the result of this study into the part design of the vehicle of rail road. And it is possible to be grafted onto the convergence technique at design and show the esthetic sense.

• Journal of the KSME
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• v.55 no.2
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• pp.45-49
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• 2015

해석 및 측정 기술의 발전과 고내구성 소재 개발 등으로 인해 그동안 무한 수명으로 여겨져 왔던 천만 회의 피로수명을 넘어 운용되는 구조물들이 많아졌다. 이 글에서는 초고주기 피로현상과 이에 기초한 내구 설계의 개념 변화 및 시험법 등에 대해 소개하고자 한다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.4D
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• pp.483-489
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• 2009

The endurance of expansion joint manufactured the Fe-Mn damping alloy reducing noise and vibration is analyzed into FEM (Finite Element Method) and fatigue test. The fatigue test have been performed using the expansion joint manufactured Fe-Mn damping alloy and the hydraulic actuator (25tonf). And the results of fatigue test show that the maximum strength is 237.6 MPa. Also that is 56.6 percent of Fe-Mn damping alloy yield strength (420 MPa). The loading plate size is prepared $57.7cm{\times}23.1cm$ and the loading plate's set position is located on expansion joint. The expansion joint manufactured the Fe-Mn damping alloy had not presented breaking behavior against 2,000,000 times fatigue test and identified the fatigue endurance.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.69-72
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• 2008

Bridge bearings are devices absorbing the displacements of the superstructure. Elastomeric bearings used generally as bridge bearings absorb the displacements of the superstructure using their rubber characteristics. Elastomeric bearings should make sure their shear fatigue performance not to impede the durability of bridge system. In this paper shear fatigue tests were performed and stiffness were measured through the shear fatigue tests. Tests results show the measured stiffness of elastomeric bearings have no specific tendency. This paper found that elastomeric bearings show bad shear performance or fail early if elastomeric bearings are manufactured with a doublefold elastomeric layer.

• Journal of the Korea Convergence Society
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• v.10 no.7
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• pp.149-154
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• 2019

This paper is to study the durability through structural analysis on the front undercover of SUV car for offroad. It was investigated which model became structurally best by analyzing three kinds of models which are similar to the configuration of undercover for the protection of the part under car body which has been used really. The models of undercover were designed through CATIA program and analyzed by using ANSYS program as three kinds of models A, B and C. Through the analysis results, model B was expressed to have the best durability as model B has the least equivalent stress and the longest fatigue life among three models. As the design data with the durability of undercover obtained on the basis of this study result are utilized, the esthetic sense can be shown by being grafted onto the machine or structure at real life.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.5
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• pp.1320-1329
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• 1990

A static performance tester for a torque rod assembly was developed to evaluate the three characteristics of the rod rubber bushing : radial spring characteristic, thrust spring characteristic, and rotational torque characteristic. Among the various schemes considered in the conceptual design stage, the final versatile type was determined to perform three different tests in one machine. The performance testing machine carried out radial spring test, thrust spring test, and torque test of the torque rod assembly. Static performance of the torque rod assembly was evaluated with the tester developed and fatigue strength of the assembly was also tested with the servo-hydraulic structural fatigue testing machine. The life of the component was found to be related with the rubber quality and adhesionability between the rubber and the steel rod. The optimum rubber hardness was experimentally found by changing the chemical compositions of rubber, and the adhesion was improved by optimizing the shape of the outer section of a the rubber, this study ensured the development of a reliable torque rod assembly.