Special Issues - 전기자동차 보급과 충전인프라 구축

한승호,Han, Seung-Ho 대한전기협회 2010 전기저널 Vol.- No.402

논단 3 - 하천 수변녹지 및 생태벨트 조성기술 개발

한승호,조용현,Han, Seung-Ho,Jo, Yong-Hyeon 한국하천협회 2009 하천과 문화 Vol.5 No.4

비드형상 및 복수 표면균열의 확률적 특성을 고려한 필릿 용접부 피로수명 평가

한승호,한정우,Han Seung-Ho,Han Jeong-Woo 대한용접접합학회 2005 대한용접·접합학회지 Vol.23 No.3

The fatigue life of welded joints is associated with crack initiation and propagation life. Theses cannot be easily separated, since the definition of crack initiation is vague due to the initiation of multiple cracks that are distributed randomly along the weld toes. In this paper a method involving a notch strain and fracture mechanical approach, which considers the characteristics of welded joints, e.g. welding residual stress and statistical characteristics of multiple cracks, is proposed, in an attempt to reasonably estimate these fatigue lives. The fatigue crack initiation life was evaluated statistically, e.g. the probability of failure occurrence in 2.3, 50 and $97.7\%$, in which the cyclic response of the local stress/strain hi the vicinity of the weld toes and notch factors derived by the irregular shape of the weld bead are taken into account. The fatigue crack propagation life was simulated by using Monte-Carlo method in consideration of the Ad-factor and the mechanical behavior of mutual interaction/coalescence between two adjacent cracks. The estimated total fatigue life, $(N_T)_{P50\%}$, as a sum of crack initiation and propagation life under the probability of failure occurrence in $50\%$ showed a good agreement with the experimental results. The developed technique for fatigue lift estimation enables to provide a quantitative proportion of crack initiation and propagation life in the total fatigue life due to the nominal stress range, ${\Delta}S$.

철강구조물 부재의 강도평가 및 피로균열진전거동

한승호,김정규,Han, Seung-Ho,Kim, Jung-Kyu 대한기계학회 1997 大韓機械學會論文集A Vol.21 No.10

The residual safety assessment of steel structures, an important subject in practice, is given to much attention. Life prediction in the planning course of steel structures under fatigue loading is mainly based on fatigue design criteria resulting from S-N curves. But for any reason cracks have to be assumed due to fabrication failures or fatigue loading in service which can lead total fracture of structures. The life prediction can be carried out by means of fracture mechanics using Paris-Erdogan equation($da/dN=C {\cdot}{\Delta}K^m$). The paper presents results from charpy test to interpret transition behaviour of charpy energy($A_V$) in a wide temperature range and from constant-load-amplitude test to measure fatigue crack growth of various steels widely used in steel bridges since beginning of 20 centuries in Europe. In the normal service temperature range of steel bridges, the steel S355M shows higher maximum charpy energy($A_{Vmax}$) and lower transition temperature($T_{AVmax/2}$) than other steels considered. The C and m of Paris-Erdogan equation on the steels appear to be correlated, and to be affected by the R-ratios due to crack closure, especially at a low fatigue crack growth rate. Scanning electron microscopy analysis was carried out to interpret an influence of the crack closure effects on the correlation of C and m.

피로강도해석을 위한 용접잔류응력 이완의 정량적 평가

한승호,이탁기,신병천,Han, Seung-Ho,Lee, Tak-Kee,Shin, Byung-Chun 대한기계학회 2002 大韓機械學會論文集A Vol.26 No.10

It is well known that the strength and the fatigue life of welded steel components are affected extensively by welding residual stresses distributed around their weldments under not only monotonic but also cyclic loads. The externally applied loads are to be superimposed with the welding residual stresses, so that unexpected deformations and failures of the components might occur. These residual stresses are not kept constant, but relaxed or redistributed during in service. Under monotonic loads the relaxation takes place when the sum of external and welding residual stress exceeds locally the yield stress of material used. By the way, it is shown that under cyclic loads the welding residual stress is considerably relieved by the first or the early cycles of loads, and then gradually relaxed with increasing loading cycles. Although many investigations in this field have been carried out, the phenomenon and mechanism of the stress relaxation are still not clear, and there are few comprehensive models to predict amount of relaxed welding residual stress. In this study, the characteristics of the welding residual stress relaxation under monotonic and cyclic loads were investigated, and a model to predict quantitatively amount of welding residual stress relaxation was proposed.

패널형 입면녹화의 시각적 만족도에 관한 연구

한승호,김선혜,송규성,Han, Seung-Ho,Kim, Sun-Hae,Song, Kyu-Seong 한국조경학회 2008 韓國造景學會誌 Vol.36 No.2

도시가 산업화 되어가면서 도심의 토지이용이 과밀화되고 건축물의 면적이 늘어나고 있다. 이에 건축물 녹화가 옥상 및 벽면을 중심으로 적극적으로 조성되고 있으며, 입면녹화의 경우 건물이 고층화 되면서 입면적이 넓어 벽면녹화가 도심에서 효과적인 녹화수단으로 인식되고 있다. 특히 패널타입의 녹화수법은 조기 녹화와 설치 시공의 편리함으로 점차 이용이 증가하고 있다. 그러나 패널타입에 대 한 연구는 대부분 식생 하부 시스템이나 관수시스템을 중심으로 이루어지고 있으며, 경관 중심에 대한 연구는 전무한 실정이다. 이에 본 연구에서는 패널형 입면녹화의 경관평가를 통하여 선호요소를 추출하고자 한다. 설문은 패널형 입면녹화가 설치된 장소의 이용자들을 중심으로 직접조사를 하였다 연구 결과, 자연스럽다는 형용사에서 3.80으로 가장 높은 점수를 나타났다. 이는 옹벽이나 건축물 벽면이 드러나는 것보다 녹화를 하는 것이 이용자들에게 긍정적인 반응을 보이는 것으로 사료된다. 다음으로 친근한(3.70), 편안한(3.65), 아름다운(3.65), 안정감 있는(3.50)가 긍정적인 경관이미지로 나타났다. 반면 정적인, 적막한, 소박한, 무거운, 우중충한, 어두운, 지저분한의 부정적 경관 이미지가 나타났는데, 이는 관리가 제대로 이루어지지 않기 때문으로 사료된다. 이러한 연구 결과를 통하여 패널형 입면녹화의 개발과 보급에 필요한 기초자료로 활용하고자 한다. As cities become more industrial and modern, they become overcrowded and the construction zones increase accordingly. In particular, the demand for panel-type planting methods has gradually increased due to early planting and easy installation. However, studies on panel-type planting have strictly concentrated on the vegetation sub system or irrigation system without any interest in landscape-centered system. Factors of preference will be made through landscape evaluation on the panel-type facade planting. A questionnaire survey was conducted in a location where panel-type facade planting was available. In terms of responses to the facade planting, 'natural (3.80)' was the highest, followed by 'friendly (3.70),' 'comfortable (3.65),' 'beautiful (3.65),' and 'peaceful (3.50).' On the contrary, negative responses such as 'too quiet,' 'simple,' 'heavy,' 'gloomy,' 'dark,' and 'dirty' were also received. It is thought that these responses refer to the poor management of the area. The results of this study will be useful as basic data for the development and distribution of panel-type facade planting.

에너지 하베스팅 응용을 위한 압전 세라믹 파이버-폴리머 복합소재의 연구 동향

한승호,강형원,이우성,박성대,백동수,Han, Seung-Ho,Gang, Hyeong-Won,Lee, U-Seong,Park, Seong-Dae,Baek, Dong-Su 한국전기전자재료학회 2010 전기전자재료 Vol.23 No.9

고장력 강판 부분용입 맞대기 용접부의 피로균열진전수명 평가

한승호,신병천,이웅,최전호,Han, Seung-Ho,Shin, Byung-Chun,Lee, Woong,Choi, Jeon-Ho 대한용접접합학회 2003 대한용접·접합학회지 Vol.21 No.1

Fatigue behaviour of partially penetrated butt-welded joints in high strength steel plates, in which crack-like structural defect, i.e. lack of penetration(LOP), is inevitably introduced during welding processes, was investigated. Fatigue lives of two types of welded joints, namely X-grooved and K-grooved joints, were experimentally determined first. Observed fatigue crack propagation behaviours of the partially penetrated butt-welds were interpreted through considering 3-dimensional semi-elliptical crack shape in front of the LOP. Based on such interpretation, a fracture mechanical method to estimate stress intensity factors at the crack tip was proposed. Since the fatigue lift of the partially penetrated butt-welds was strongly influenced by the ratio of size of the LOP to thickness, D/t, the D/t was used as a main parameter to calculate the fatigue lift by using the proposed method. Comparison of the fatigue lift obtained experimentally and analytically agreed well with each other. Hence it is suggested that the method used in this work to predict fatigue lift of the partially penetrated butt-welds can be applied to real cases with improved lift-prediction capability.

저수형 잔디블록 저수조 내 충진재료에 따른 저수량 및 초종별 증발산량

한승호,최준수,양근모,양병이,강진형,김원태,Han, Seung-Ho,Choi, Joon-Soo,Yang, Geun-Mo,Yang, Byoung-E,Kang, Jin-Hyoung,Kim, Won-Tae 한국조경학회 2006 韓國造景學會誌 Vol.34 No.5

The purpose of this study was to investigate the performance of porous grass block. For the investigation, Festuca arundinacea and Zoysia japonica 'Zenith' were planted, and the volume of evapotranspiration and remains were examined based on different materials in the water tank in the experiment of Festuca arundinacea, the volume of water storage of treatment with perlite ($10.84{\iota}/m^2$) was higher than that with drainage ($7l/m^2$). The difference between the two was $3.84/m^2$. The drainage treatment without water storage capacity showed the higher degree of dryness in turf grass. The volume of evapo-transpiration of treatment with perlite was the highest (21.57mm/week). The volume of evapotranspiration of treatment with sand was 19.57mm/week, and with treatment with drainage was 18.24mm/week. Based on the measured volume of daily evapotranspiration of $2.60{\sim}3.08mm\;d^{-1}$, it was determined that the unit with water storage capacity would store water of one to two days usage compared to unite without such storage capacity. In the experiment of Zoysia japonica 'Zenith', the volume of water storage of treatment with perlite was $10.77l/m^2$ which was similar to the former experiment. The volume of evapotranspiration of treatment with perlite and sand were 21.64mm/week and 20.64mm/week, respectively. In case of airtight water tank, the volume was measured as 22.06mm/week. Each treatment has no notable difference in the volume of evapotranspiration. In conclusion, from the investigation in this study, porous grass block with water tank was found to be effective in plant growth under low irrigation. As the ecological area ratio and vegetated porous pavement have became more emphasized, additional study of rain infiltration and reservoir effect are needed in the future.

투수성 잔디블록 포장 하부 토양의 물리성

한승호,김원태,강진형,Han, Seung-Ho,Kim, Won-Tae,Kang, Jin-Hyoung 한국조경학회 2006 韓國造景學會誌 Vol.34 No.4

Impervious pavement is primary contributor to the malfunctioning of the urban water circulation system. The aim of this research is to provide basic information and data for new pavement materials and paving technology which could enhance the urban water circulation system. For the study purposes, physical properties of soils sampled from 16 stations were analyzed. The sampling spots were paved with grass block porous pavement material. The findings from the analysis are as follows. The hardness of soils under the pavement was $17{\sim}22mm$ for thoroughfare and $6{\sim}32mm$ for parking areas. The bulk density was $1.42{\sim}1.81g/cm^{3}$ for thoroughfare and $1.38{\sim}1.75g/cm^{3}$ for parking area. The solid phase ration was $46.9{\sim}62.5m^{3}/m^{3}$ for thoroughfare and $45.6{\sim}61.3m^{3}/m^{3}$ for parking area. The porosity was $37.5{\sim}53.1m^{3}/m^{3}$ for thoroughfare and $38.7{\sim}54.4m^{3}/m^{3}$ for parking area. The saturated hydraulic conductivity was $8{\sim}164mm/hr$ for thoroughfare and $14{\sim}201mm/hr$ for parking area. The saturated hydraulic conductivity of the H sample area (the area was completed three months ago) and that of the other area were compared. There was up to 80% decreases of the saturated hydraulic conductivity within one year after the completion of pavement. After the first year, decrease in the saturated hydraulic conductivity was modest. Also there are changes in both surface and under soil physical properties of the grass block porous pavement depending on compaction. The extent of change depends on the degree of compaction. All these factors are combined to influence the permeability of the soil under the pavements. The results of this suggest that it is required to develop a new pavement technology which ensures both the durability and porosity of the pavement to improve the water circulation system by applying Ecological Area Rate.