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        검색결과 284

        61.
        2018.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to improve the durability by solving the crack problem of the steering gearbox bracket welded to the frame assembly. For the exact and effective analysis, we use charac- teristic(fishbone) diagram from the viewpoint of 4M1E. Through this analysis it was identified two kinds of problems, and develop improvement plan for it. Verification tests must be performed to confirm the improvement. So, the test method for steering gearbox bracket improvement was newly established by referring to similar case. As a result of the tests for verification, the stresses at crack point are decreased and the durability was improved about 2.6 times compared with product before improvement.
        4,000원
        62.
        2018.04 구독 인증기관 무료, 개인회원 유료
        기존의 교면 포장이나 측구 시공에 적용한 건설재료들의 성능저하로 인해 유지보수비가 증가하고 있는 추세이다. 이에 본 연구에서는 현장 실험을 통해 개질유황 콘크리트의 내구성을 평가하는데 있어 기존의 고정형 팬믹서와 건 비빔 시 자전속도 변환이 가능한 가변형 팬믹서를 이용하여 내구성 평가 시험으로 콘크리트의 압축강도 시험을 수 행하였다.
        3,000원
        63.
        2018.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : It is necessary to prevent premature failure of concrete pavements caused by durability problems. The purpose of this study was to find factors affecting the durability of concrete pavements, and suggest improvement methods for existing concrete mix design. METHODS: Factors influencing durability were derived from laboratory test data for common field failure conditions and main properties of concrete cores taken from the field. The improvement of concrete properties was investigated by evaluating the performance of existing and proposed mix proportion designs and curing methods. RESULTS: The compressive strength and the absorbing performance of the low Blaine cement and the high-strength mixture were better than those of the TypeⅠcement. Wet curing showed better compressive strength, elastic modulus, coefficient of thermal expansion, and absorption performance than air curing or compound curing. As a result of comparing concrete cores collected in the field, the sections with good durability showed good performance in terms of resistance to chloride ion penetration, absorption, and initial absorption rate. CONCLUSIONS: The absorption performance was considered as a possible foactor affecting durability of cement concrete pavements as a result of field core tests. In order to improve the durability of the pavement concrete, it is necessary to improve the existing mixtures and curing methods.
        4,000원
        66.
        2017.11 구독 인증기관·개인회원 무료
        분리막은 최초 개발 이후 소비자의 요구에 부합하기 위해 지속적으로 개발되어 왔으며 그 과정 중 혁신적인 기술 개발에 의해 상업적 적용과 패러다임의 변화가 이루어져 왔다. Roeb & Sourirajan의 비대칭막 개발 및 Cadotte의 복합막 개발, Yamamoto 의 침지막의 개발은 기존 분리막의 틀을 넘어서 상업적 적용과 대량생산을 가능하게 하는 계기가 되었다. 현재 분리막 시장은 분리막에 소모품의 개념을 넘어 내구재의 특성을 요구하고 있으며, 생산기술은 이러한 요구에 부합하기 위해 NIPS와 TIPS개념을 넘어 다양한 융합기술로 끊임없이 진화하고 있다. 이에 우리는 평막의 안정성과 중공사의 집적도를 갖으며, 세라믹막의 내구성과 안정성을 대체함과 동시에 고분자막의 장점을 잃지 않는 플라워 & 클로버 멤브레인의 개발을 통해 분리막에 새로운 패러다임 제시하고자 한다. 플라워 멤브레인은 융합생산기술을 통해 MF/UF/PV 등 다양한 분야에 적용 가능하다.
        67.
        2017.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper uses finite element analysis to analyze the equivalent stress and fatigue duration distributed in the timing belt pulley of the rotating part. The pulley structure used for analysis was categorized into one body type and separate axis type and their characteristics were analyzed when materials S45C and SCM440-870C were applied. A static structural analysis and durability analysis show that when external forces are applied to the pulley, the separate axis structure is structurally safer and more favorable in terms of fatigue, compared to the one body. In addition, the separate axis structure using SCM440-870C material was found to have the best safety factor at 10.4 and infinite fatigue life. These findings are expected to be useful when manufacturing timing belt pulleys.
        4,000원
        69.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aim of this paper is to clarify the structural stability of Refracted Telescopic Boom in 30m Class with the Property of Working Range Insulation. The boom of insulation special vehicle consists of a 3-stage telescopic boom, 2-stage refracting boom, insulation boom and effector. The catia solid geometry of the boom was used to generate both a basic ADAMS model and the finite element meshes for the flexible components. The flexible bodies were generated by using the finite element program of ANSYS and then imported into the ADAMS model and their flexibility accounted to the dynamic analysis of boom. Embedding finite element representations within the ADAMS model, offers the advantage being able to perform the durability analysis and the resulting damage. Through this approach, the crack locations(hot spots) in a prototype can be predicted successfully, thereby validating the analysis procedure.
        4,000원
        71.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we investigated to the heat transfer performance of coating nano-structure with various shapes and patterns on the heat transfer surface. As a result of the measurement of the 3D nano shape, it was confirmed that the roughness generally increases when the adhesive is sprayed on the coating surface and finished durability experiment. In the case of TEOS adhesive, the roughness increased by 0.074 ㎛, 0.012 ㎛ and 0.015 ㎛, and the contact angle decreased 12.64°, 1.31°, 9.84° at the coating time of 120 seconds, 180 seconds and 240 seconds, respectively. In the case of PVA adhesive, the roughness increased by 0.069 ㎛, 0.056 ㎛ and 0.03 ㎛, and the contact angle decreased 2.85°, 4.82°, 6.96° at the coating time of 120 seconds, 180 seconds and 240 seconds, respectively. In the case of DGEBF adhesive, the roughness increased by 0.042 ㎛, 0.053 ㎛ and 0 ㎛, and the contact angle decreased 0.81° at the coating time of 120 seconds, increased 4.82°, 6.96° at the coating time of 180 seconds and 240 seconds, respectively. As a result, the durability tends to decrease as more nano-structures are deposited, and 3D nano shapes, contact angles and SEM photographs showed that the performance of the PVA adhesive was superior among the three adhesives.
        4,000원
        72.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The composite material has the strong durability and light weight as inhomogeneous material. Nowadays, CFRP composite has been noticed as the light weight, high strength and long fatigue life. This study has been carried actively. In this study, the properties of tensile strengths of CFRP, stainless steel are analyzed, and compared each other. In order to secure the data, the tensile specimens with notches of same size by using CFRP, and stainless steel are manufactured and experimented. When the forced displacement of about 11.5 mm proceeds in case of stainless steel specimen, the maximum load of 31000 N is shown simultaneously with the fracture of specimen. When the forced displacement of about 6 mm proceeds in case of CFRP specimen, the maximum load of 16000 N is shown. So, the structural safety becomes highest at CFRP specimen among these specimens. In this study, the finite element analysis is carried out in order to compare with the experimental results. It is verified that the experimental and analysis results are similarly shown each other. Through the result of this study, it is thought that the simulation analysis data with no experiments are trustworthy at using as the real tensile experimental data.
        4,000원
        74.
        2016.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        나노실리카가 코팅된 유리 표면은 나노실리카 표면에 존재하는 친수성 수산기로 인해 방담성 이 매우 증가하나, 실외에 설치된 유리에 코팅된 경우는 비에 의해 씻겨 나가 방담 특성의 내구성이 급 격히 감소한다. 또한 나노실리카가 코팅된 유리 표면의 토폴로지는 광투과율 또는 반사방지 특성을 좌우 하는 매우 중요한 인자이다. 이러한 나노실리카 코팅의 특성에 관한 내구성을 향상시키기 위하여 가교제 로 테트라에틸오르소실리케이트 (TEOS)를 사용하여 나노실리카 (Ludox) 현탁액으로 친수성 나노실리카 피막을 제조하였다. 산성 또는 염기성 수용액 중에서의 TEOS의 가수 분해 최적 조건도 물에 대한 접촉 각 측정을 통하여 조사하였다.산성 또는 염기성 수용액 중에서의 TEOS의 가수 분해 최적 조건도 물에 대한 접촉 각 측정을 통하여 조사하였다. pH=4의 산성 조건에서 1.5 wt% 나노실리카-TEOS 코팅액으로 얻은 최종 투명한 친수성 코팅층은 매우 향상된 친수성에 대한 내구성뿐만 아니라, 코팅하지 않은 유리에 비해 약 2 % 포인트 정도 높은 가시광투과율을 나타내었다.
        4,000원
        75.
        2016.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        An aluminum with the light weight has been used at the automotive car body. As the aluminum is applied to the automotive seat, the optimum design becomes important by investigating the mechanical properties. This study aims at suggesting the basic data for the optimum design of automotive seat frame. In this study, the mechanical properties are investigated through the simulation analysis on the entire structure of seat frame. Two study models using the real commercial vehicles are designed with CATIA program and analyzed with ANSYS program. The harsh condition during the driving state is supposed by using the analyses of natural frequencies and harmonic responses. As the real frequency ranges in this study are set by selecting the natural frequencies through modal analysis. The critical frequencies are analyzed by harmonic response on which the driver is seated. The values of maximum equivalent stresses at models 1 and 2 are shown to be 18.073MPa and 2259.2MPa respectively. The critical frequency at models 1 and 2 are also shown to be 77 Hz and 206 Hz. The maximum stress at model 1 becomes far bigger than model 2. By comparing two models, model 1 has more critical condition than model 2. At the design of automotive seat frame at the dynamic vibration condition, the material of design with the durability and safety can be secured through this study result.
        4,000원
        76.
        2016.07 구독 인증기관 무료, 개인회원 유료
        As mass production techniques developed in technological innovation due to the industrial revolution, the world started to face serious pollution problem and therefore ‘sustainable’ and ‘eco-friendly’ movement showed up in our societies. The fashion industry has emphasized the environmental design since the early 1960s. However, in the system engaged on trends and mass-production process, fashion designers and consumers could not pay more attention to the environment issues as expected. In these days, consumers not just in fashion products but also any other products started to care about ‘fair trades’, ‘environmental issues’, ‘human rights’, and ‘donations’ when they shop. Therefore, if fashion industries pay more attention to sustainable marketing and merchandising while selling their products, it will help consumers to build up a ‘sustainable thinking’. Usage of eco-friendly materials and recycling are well-known for practicing eco- friendly fashion but unfortunately, they are only limited in the process of making and disposal stage in fashion. Nowadays, there is an increasing concern and emphasis on fair trade, environmental awareness, human rights and other ethical consumerism practices, and is growing in tendency, which has prompted authentic and honest marketing strategies to become more effective as opposed to the existing one-shot events (Kim et al., 2013). If this trend of planning business strategies with authentic and sustainable tactics is implemented into the Fashion industry, then it will be able to establish a sustainable consumer culture. Until now, contemporary research on environmentally friendly and sustainable fashion are mostly centered on sustainable fashion ideas and studies on sustainable textiles (Fletcher, 2011). However, there was limited studies on sustainable design with various perspectives and design planning, which have much practical and real-world usage for designers or planners in the fashion industry. Therefore, it is necessary to conduct more studies on fashion design planning methods and guidelines that fashion merchandisers and designers in the industry can use.
        4,000원
        77.
        2016.06 구독 인증기관 무료, 개인회원 유료
        본 연구는 자원봉사자가 인식하는 노인복지시설의 사회적 책임이 자원봉사 지속성에 미치는 영향에 대하여 조직신뢰 조절효과를 검증하였다. 연구 자료는 2013년 9월부터 12 월까지 서울, 경기권 노인복지시설의 20대 이상 성인 남녀 자원봉사자의 설문지 237부의 설문자료를 분석하였으며, 통계프로그램 SPSS 18로 조절회귀분석을 통계분석방법으로 사용하였다. 측정도구는 독립변수로 자원봉사자가 인식하는 노인복지시설의 사회적 책임, 조절변수로는 조직신뢰, 종속변수로는 자원봉사 지속성을 측정하였다. 연구결과 노인 복지시설의 사회적 책임 중 윤리적 책임과 조직신뢰의 상호작용이 조절효과가 나타나는 것으로 나타났다. 이에 따라 노인복지시설의 사회적 책임이 자원봉사 지속성을 검증한 점에서 연구의 의의가 있으며, 이상과 같은 결과를 통하여 노인복지시설에서 자원봉사자들의 지속성을 높이기 위하여 사회적 책임을 실천해야 하는 함의를 제시하였다.
        4,700원
        78.
        2016.05 구독 인증기관 무료, 개인회원 유료
        In this study, the analyses of structure, fatigue and vibration with two models of 1 and 2. As the result of structural analysis, the equivalent stress and the total deforamtion of model 1 become higher than those of model 2.Model 1 shows fatigue life more than model 2. As the vibration analysis, model 1 has the safety better than model 2. As shown by these results, the main parts ofdamage and the weak areas can be investigated to differ from each other according to the configuration of model though these models have the same material property. The result of this study through the analysis can be applied to develop the optimal design of automotive seat frame with durabilty and safety.
        3,000원
        79.
        2016.05 구독 인증기관·개인회원 무료
        본 발표에서는 고분자막의 열화(Degradation)원인과 열화 조건, 열화방지 방법, 고분자막 내구성 평가 방법 등에 대해서 논의하고자 한다. PEMFC 고분자 막의 열화원인은 전기화학적인 열화를 포함한 화학적인 열화와 물리적인 열화, 열에 의한 열화로 분류할 수 있다. 고분자 막이 전기화학적열화가 잘되는 조건은 OCV와 같은 높은 전압, 저 가습, 고온, 높은 수소/산소 압력 조건이다. 고분 자막의 내구성을 평가하기 위해서 열화 가속화 기법을 사용하는데, 전기화학적 내구성은 OCV holding 기법을, 물리적 내구성은 Wet/Dry 기법을 일반적으로 사용한다. 이들 내구성 평가 방법에 관한 미국의 DOE 프로토콜과 일본의 NEDO 프로토콜을 비교 검토한다.
        80.
        2016.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The use of roller-compacted concrete pavement (RCCP) is an environmentally friendly method of construction that utilizes the aggregate interlock effect by means of a hydration reaction and roller compacting, demonstrating a superb structural performance with a relatively small unit water content and unit cement content. However, even if an excellent structural performance was secured through a previous study, the verification research on the environmental load and long-term durability was conducted under unsatisfactory conditions. In order to secure longterm durability, the construction of an appropriate internal air-void structure is required. In this study, a method of improving the long-term durability of RCCP will be suggested by analyzing the internal air-void structure and relevant durability of roller-compacted concrete. METHODS: The method of improving the long-term durability involves measurements of the air content, air voids, and air-spacing factor in RCCP that experiences a change in terms of the kind of air-entraining agent and chemical admixture proportions. This test should be conducted on the basis of test criteria such as ASTM C 457, 672, and KS F 2456. RESULTS : Freezing, thawing, and scaling resistance tests of roller compacted concrete without a chemical admixture showed that it was weak. However, as a result of conducting air entraining (AE) with an AE agent, a large amount of air was distributed with a range of 2~3%, and an air void spacing factor ranging from 200 to 300 ㎛ (close to 250 ㎛) coming from PCA was secured. Accordingly, the freezing and thawing resistance was improved, with a relative dynamic elastic modulus of more than 80%, and the scaling resistance was improved under the appropriate AE agent content rate. CONCLUSIONS: The long-term durability of RCCP has a direct relationship with the air-void spacing factor, and it can be secured only by ensuring the air void spacing factor through air entraining with the inclusion of an AE agent.
        4,000원
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