• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.155-160
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• 2001

The road simulator system can simulate the longitudinal, lateral, and vertical movement changed by road conditions and vehicle dynamic characteristics while driving. This system provides the durability evaluation of vehicle suspensions. The system consists of hydraulic actuators, link mechanism, and servo controller. The hydraulic actuators are specially manufactured using low friction seals to endure high speed movement. The link mechanism is designed in order to minimize the dynamic effect during motion and remove the interference between 3axes actuators. The servo controller is composed of sensors, sensor amplifiers - displacement transducers and load cells, and an industrial PC with DSP board which calculates the control algorithm to control hydraulic actuators. The test results are included to evaluate the performance of this simulator comparing vehicle driving test.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.3
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• pp.103-110
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• 2014

In this study, spur and helical box models of an existing machine tool are investigated using structural and fatigue analyses. As the helical box model is shown to have less stress and deformation than those characteristics of the spur box model, the helical box has more strength and more transmission efficiency on the structure. In terms of fatigue analysis, the helical box model has more repeated fatigue strength than that of the spur box model. These study results can be effectively utilized in the design of real gear boxes of machine tools by anticipating and investigating prevention and durability against damage.

• Journal of KSNVE
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• v.10 no.4
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• pp.686-691
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• 2000

In this paper a computer aided analysis method is proposed for durability assessment in the early design stages using dynamic analysis, stress analysis and fatigue life prediction method. From dynamic analysis of a vehicle suspension system, dynamic load time histories of a suspension component are calculated. From the dynamic load time histories and the stress of the suspension component, a dynamic stress time history at the critical location is produced using the superposition principle. Using linear damage law and cycle counting method, fatigue life cycle is calculated. The predicted fatigue life cycle is verified by experimental durability tests.

• Corrosion Science and Technology
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• v.4 no.5
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• pp.201-206
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• 2005

Starting with the meaning of the word quality, diverse concepts connoted by the term are examined. Instead of a bathtub curve, the desirable shape of a failure rate covering the entire life of a good product, which might be called hockey-stick line, is introduced. From the hockey-stick line and the definition of reliability, two measurements are extracted. The terms r-reliability (failure rate) and durability (product life) are explained. The conceptual analysis of failure mechanics explains that reliability technology pertains to design area. The desirable shape of hazard rate curve of electronic items, hockey-stick line, clarifies that Mean-Time-to-failure (MTTF) as the inverse of failure rate can be regarded a nominal life. And Bx life, different from MTTF, is explained. Reliability relationships between components and set products are explained. Reshaped definitions of r-reliability and durability are recommended. The procedure to improve reliability and the reasons for failing to identify failure mode are clarified in order to search right solutions. And generalized Life-Stress failure model is recommended for the calculation of acceleration factor.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.4
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• pp.180-184
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• 2012

3-way ball valves have been mostly used for high temperature/high pressure valves using in petrochemical carriers and oil tankers, which requires high quality products with confidentiality and durability. As a larger disaster may be generated by leakage of oil or gas from valves, thus the present research applied a numerical analysis method with thermal-structural coupled field analysis and the performance test. The Max stress by parts was confirmed through thermal-structural coupled field analysis and develop the 3-way ball valve design, which is safe on operating condition. And its performance was verified by carrying out pressure test, leakage test and durability test for the manufactured 3-way ball valves with satisfying it's regulations.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.3
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• pp.14-21
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• 2020

The automotive seat appropriately absorbs the vibrations or shocks transmitted through a vehicle when it is in operation so as to provide a comfortable ride for passengers. In this study, the structural strength and durability of each model were investigated using structural analysis. The natural and critical frequencies at the seat were analyzed through vibration analysis. Through the results of this study on automotive seat frame models, the durability against the load and vibration is shown to be dependent on the configuration of the model.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.229-232
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• 2005

Protective surface coating for concrete is available for applying to concrete structures for protecting chloride attack. However, the useful data obtained from real marine environment for surface coating materials is not sufficient yet in Korea and thus the engineers face many difficulties to apply the coating method in durability design. Surface-coated concrete specimens were fabricated and installed around the piers of Seohae grand bridge to observe long-term performance in actual marine environment. In this study, the results of durability of surface coatings for 3 years were reported.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.149-150
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• 2018

The RC buildings which are constructed on the seaside are followed by KBC(2016) to achieve the minimization of durability damage. To control the corrosion of the reinforced steel bar by salt attack, W/C should be under 0.4 and specified concrete strength is more than 35MPa in the concrete/building construction standard specification. Ready mixed concretes which have usually include the admixtures in Busan were tested to certify the salt attack durability. In the same specified concrete strength, remarkable salt attack durability was evaluated in comparison to OPC.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.2
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• pp.8-13
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• 2013

This study analyzes about poclain bucket through fatigue durability analysis. Maximum equivalent stress and total deformation are shown at the lower of bucket and edge part respectively. 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 -10000Pa to 5000MPa and the amplitude stress of 0 to 6000MPa, the possibility of maximum damage becomes 3%. This stress state can be shown with 5 or 6 times more than the damage possibility of 'SAE bracket history' or 'SAE transmission'. The structural result of this study can be effectively utilized with the design of poclain bucket by investigating prevention and durability against fatigue damage.

• Prospectives of Industrial Chemistry
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• v.22 no.4
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• pp.1-12
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• 2019

최근 전 세계적으로 이상화탄소 배출규제에 대응하기 위해 신에너지를 동력원으로 하는 자동차에 관심이 증가하고 있다. 그중 이온 교환막 연료전지(PEMFC)는 내연기관을 대신에 자동차 동력원으로 많이 사용되어지고 있으며 양산화를 위한 노력을 전 세계적으로 하고 있다. 하지만 이러한 수소 자동차가 시장과 소비자의 요구 조건을 충족하기 위해서는 내구성을 개선하여야 한다. 현재 선진사들을 중심으로 수소 자동차의 내구성을 개선하기 위해 노력하지만, 대부분 실험적 방법으로 내구성의 분석 및 평가를 수행하고 있다. 하지만, 이러한 방법은 비용과 시간이 많이 들기 때문에 경제적이지 못하다. 본 기고문에서는 내구성에 영향을 받는 인자, 연료전지 시스템 내구성을 예측하고 평가할 수 있는 수소 자동차 내구성 모델 개발에 필요한 수식에 관한 연구, 그리고 내구성 개선을 위한 해석적 방법(simulation)에 관한 연구 동향을 소개하고자 한다.