• 대한기계학회논문집A
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• 제33권11호
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• pp.1225-1232
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• 2009

This study suggests a structural design process for the upper control arm installed at a vehicle. Static strength and durability are the most important responses in the structural design of a control arm. This study considers the static strength in the optimization process. The inertia relief method for FE analysis is utilized to simulate the static loading conditions. According to the classification of structural optimization, the structural design of a control arm is included in the category of shape optimization. In this study, the metamodel technique using the kriging method is adopted to obtain the minimum weight satisfying the strength constraint. Then, the final design is suggested by considering the durability criteria. The durability assessment is obtained by the index of fatigue durability called the SWT (Smith-Watson-Topper) index. The final optimum shape has been proposed by trial and error method.

• 한국기계가공학회지
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• 제14권2호
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• pp.44-50
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• 2015

This study investigated the durability of the under bar of a car through structural and fatigue analysis. Model 1 had the lowest value among three kinds of models. In the case of the maximum equivalent stress and displacement at structural analysis, model 1 showed the highest durability. Also, models 3 and 2 showed structural durability in order of this value. In the case of fatigue analysis, the maximum fatigue lives of the three models were equal to $2{\times}10^7$cycles. However, model 1 showed the highest value among the three models, as the minimum fatigue life of model 1 becames 92.56 cycles. Also models 3 and 2 showed fatigue durability in order of this value. The maximum possibility of fatigue damage for models1,2,and 3 became 30%. If the results of this study are applied to change the design shape of the under bar of cars, the ride comfort for automobile passengers and car durability can be improved.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
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• pp.421-426
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• 1999

The purpose of this study is to investigate the durability design method of reinforced concrete structure in order to establish a rationally combined design system of structural and durability design, that is to say performance-based design. In literature study, the integrated design of concrete structure studied JCI committe is very intensive durability design method for reinforced concrete structure. Specially, B root durability design method for selection of verification level is very effective method in the view of modeling of materials and structural properties to analyze safety and serviceability of RC structures.

• 한국자동차공학회논문집
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• 제21권6호
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• pp.166-174
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• 2013

This study investigates the strength durability on the results of structural and vibration analysis due to the shape of excavator wheel. As model 2 has the least stress by comparing three models with maximum equivalent stress, model 2 has most durability among three models at static analysis. Maximum equivalent stress is shown at the bottom part contacted with ground and this part on wheel is most affected by load in cases of all models. Safety factor can be decided with the value of 2.3 by considering the yield stress of this model. The range of maximum harmonic response frequencies becomes 6900 to 7000Hz. As model 2 has the least total deformation and equivalent stress at these critical frequencies, model 2 has the most durability at vibration analysis among three models. The structural and vibration analysis results in this study can be effectively utilized with the design of excavator wheel by investigating prevention and durability against its damage.

• KIEAE Journal
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• 제7권4호
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• pp.141-146
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• 2007

It is necessary to guarantee the safety, serviceability and durability of reinforced concrete structures over their service life. However, concrete structures represent a decrease in their durability due to the effects of external environments according to the passage of time, and such degradation in durability can cause structural degradation in materials. In concrete structures, some degradations in durability increase the corrosion of embedded rebars and also decrease the structural performance of materials. Thus, the structural condition assessment of RC materials damaged by corrosion of rebars becomes an important factor that judges needs to apply restoration. In order to detect the damage of reinforced concrete structures, a visual inspection, a nondestructive evaluation method(NDE) and a specific loading test have been employed. However, obscurities for visual inspection and inaccessible members raise difficulty in evaluating structure condition. For these reasons, detection of location and quantification of the damage in structures via structural response have been one of the very important topics in system identification research. The main objective of this project is to develope a methodologies for the damage identification via static responses of the members damaged by durability. Six reinforced concrete beams with variables of corrosion position and corrosion width were fabricated and the damage detections of corroded RC beams were performed by the optimization and the conjugate beam methods using static deflection. In results it is proved that the conjugate beam method could predict the damage of RC members practically.

• 한국자동차공학회논문집
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• 제14권3호
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• pp.68-74
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• 2006

The evaluation of durability performance in Virtual Testing Laboratory(VTL) is a new concept of vehicle design, which can reduce the automotive design period and cost. In this study, the multibody dynamics model of a car is built with a reverse engineering design. Hard points and masses of components are measured by a surface scanning device and imported into CAD system. In order to simulate the non-linear dynamic behavior of force elements such as dampers and bushes, components and materials are tested with specialized test equipments. An optimized numerical model for the damping behavior is used and the hysteresis of bush rubber is considered in the simulation. Loads of components are calculated in VTL and used in the evaluation of durability performance. In order to verify simulation results, loads of components in the vehicle are measured and durability tests are performed.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.181-184
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• 2006

Traditional durability analysis is not possible to provide a controlled durability and long-term performance of concrete structures. Recently, research works have shown that probabilistic approach based on the theory of structural reliability, would be very valuable for durability analysis. In this study, the probabilistic durability analysis based on a Monte Carlo Simulation was carried out using sample data selected from detailed field investigation. The probabilistic properties of some design variables, such as diffusion coefficients of concrete and surface chloride concentration, were newly determined using some experimental data. By applying a probabilistic durability analysis to an integral structural design, the durability performance of concrete structures would be remarkably improved.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.29-46
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• 1999

The performance based design obligates quantitative assessment of required performances by means of transparent and objective science. In this design scheme, simulation of both macro and micro-scale structural behaviors is thought to be a powerful tool. This paper proposes a way how to unify the structural safety and serviceability check method and durability assessment of RC structures. Though component chemical-physical processes are crudely assumed, system dynamics of micro-scale pore structure formation and macro-scale defects and deformation of structures was shown as possible and promising approach in future. The authors understand that the unification of structural and durability design has just started. For further progress and development, predictive tool of structural behaviors from birth to death of concrete under any specified environment and load serves as an essential technicality.

• 한국기계가공학회지
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• 제19권7호
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• pp.16-21
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• 2020

The structural analyses were conducted with three models of pinion gears connected to the rack gear which is driven by the steering axle at an automobile. Three models 1, 2 and 3 are designed as the different pinion gears due to the vehicle type. The lower the value of maximum stress, the better the durability of model. Model 3 has the best durability among three models. Models 1 and 2 are expected to require the adjustment in order to improve the durability better. By the utilization of this study result, it is thought to apply at designing the pinion gear with durability at the automobile.

• 한국생산제조학회지
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• 제22권2호
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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.