• 대한기계학회논문집A
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• 제29권1호
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• pp.107-114
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• 2005

In order to analyze the elastic-plastic fracture behavior of a structure, the fracture resistance curve of the material should be known first. The standard CT specimen was used to obtain the fracture resistance curves of a piping system. However, it is known that the fracture resistance curve by the standard CT specimen is very conservative to evaluate the integrity of a structure. Also the fracture resistance curve is effected by the specimen geometry and the dimensions because of the constraint effect. The objective of this paper is to be certain the conservativeness of the fracture resistance curve by the standard CT specimen and to provide an additional safety margin. For these, the fracture tests using a real pipe specimen and the standard CT specimen test were performed. A 4-point bending jig was manufactured for the pipe test and the direct current potential drop method was used to measure the crack extension and the length for the pipe test. Also finite element analyses were performed with a CT specimen and a pipe in order to prove the additional safety margin. From the result of tests and analyses of the pipe and the standard CT specimen, it was observed that the fracture analysis with the standard CT specimen is conservative and the additional safety margin was proved.

• 한국공작기계학회논문집
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• 제11권3호
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• pp.80-85
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• 2002

The free curve gear is a non-circular gear without any relating center, which can perform free curve motion for complicated mechanisms, and minimize the work area. In this study, an algorithms for tooth profile generation of free curve involute gear is developed. The algorithm uses the involute gear creating principle in which a gear can be generated by rolling with another standard involute one. Cycloid me and third polynomial curve gears were designed and verified by computer graphics. These gears are manufactured in the wire-cut EDM and examined in engagement with a standard spur gear. The results showed that the proposed algorithm is successful to design and to manufacture the free curve gear with concave and convex profiles.

• 핵의학기술
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• 제20권2호
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• pp.69-74
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• 2016

Insulin 83건을 검사 대상으로, 장비 WIZARD(PerkinElmer, USA)와 DREAM- G-10(Shinjin, KOREA)의 Graph Algorithm 중에 표준곡선과 신뢰성이 가장 높은 Excel의 추세선은 다항식 추세선이다. 다음으로 다항식 추세선식을 이용하여 표준농도 1개씩을 제외하여 표준농도의 회귀식에 미치는 영향을 비교한 결과 최고농도($315{\mu}IU/m{\ell}$)의 평균값이 표준물질 6개로 실시한 표준 회귀식을 이용한 평균값과 비교하여 49%나 평균값이 저하되었다. 단 낮은 농도에서는 영향이 미비하였다. 마지막으로 WIZARD의 Point to Point형식과 DREAM G-10의 Point to Point형식이 적합성이 높고, DREAM G-10(Point to Point)와 Excel 다항식 추세선이 적합성이 높으며, Excel 다항식 추세선과 DREAM G-10(2'nd order Polynomial)의 적합성이 높다.

• 대한기계학회논문집A
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• 제33권9호
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• pp.930-937
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• 2009

The estimation method of the fracture resistance curve for the pipe specimen was proposed using the load ratio method for the standard specimen. For this, the calculation method of the load - CMOD curve for the pipe specimen with the common format equation(CFE) was proposed by using data of the CT specimen. The proposed method agreed well with experimental data. The J-integral value and the crack extension were calculated from the estimated load - CMOD data. The fracture resistance curve was estimated from the calculated J-integral and the crack extension. From these results, it have been seen that the proposed method is reliable to estimate the J-R curve of the pipe specimen.

• 대한기계학회논문집A
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• 제32권9호
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• pp.707-712
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• 2008

The fatigue characteristics of a material or a structure are generally derived from fatigue tests of standard specimens. However, test results of standard specimens are different from those of real structures or components. Therefore, to calculate more accurate fatigue life, the geometrical effect and surface condition must be considered by comparing test results of standard specimens with those of real structures or components. Thus the object of this paper is to evaluate the fatigue characteristics of a real waterwork pipe. Also, to evaluate fatigue characteristic based on life distribution, the statistical fatigue characteristics were analyzed by the normal distribution and related data of P-S-N curve.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.1426-1431
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• 2011

A study on the standardization of design fire HRR(heat release rate) curve was conducted for various railcar from the fire simulation or the fire tests. These standard curves are listed on the tunnel fire safety manual which will be used for the QRA(quantitative risk analysis) process of the long railway tunnels. The design fire curve is based with four simple factor representing the key of fire curve characteristics. Flashover time, maximum HRR and burn out time are the key factors of the design fire curve. Specially total heat release is decided by the burnable material amount in the car.

• 한국물환경학회지
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• 제21권5호
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• pp.516-519
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• 2005

An useful protocol coiled load duration curve methodology to estimate contaminant loading to a river on an exceedance probability scale was developed in this research. The technique was further applied to estimate total coliform loading to the Geum River, using the daily mean flow rate and total coliform concentration data during January, 1996 and July, 2004 for the Gongju where an automated monitoring station is located. Drought flow of the Gongju (=50.3 cms) was equivalent to 40% on an exceedance probability scale. Load duration curve for total coliform loading at the Gongju was constructed. Standard duration curve was constructed with the water quality criteria for the class 2 (total coliform concentration = 1000 MPN/100 mL). By plotting load duration curve with standard duration curve, it could be revealed that water quality do not meet the desired water quality for 47% on an exceedance probability scale. If linearity between flow rate and coliform concentration is assumed, it can be interpretated that water quality exceeds desired criteria when average mean flow rate is over 51 cms.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1691-1694
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• 2005

The fatigue characteristic of a material or a structure is derived from fatigue tests of standard specimens. However test results of standard specimens are very different from those of real structures or components. Therefore, to calculate more accurate fatigue life, the geometrical effect and surface condition must be considered by comparing test results of standard specimens with those of real structures or components. Thus the object of this paper is to evaluate the fatigue characteristic of a real waterwork pipe by conducting fatigue tests with standard specimens and non-standard(plate-shaped) specimens of base metal and weld metal. Also, to evaluate fatigue characteristic based on life distribution, statistical fatigue characteristic was analyzed by the normal distribution and related data of P-S-N curve.

• 한국방재학회 논문집
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• 제10권5호
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• pp.41-47
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• 2010

화해를 입은 구조물의 안전성 확보에는 초기대응이 매우 중요기 때문에 신속한 의사결정이 필요하다. 본 논문에서는 화해를 입은 구조물의 이형철근과 콘크리트 간 잔존부착강도를 평가할 수 있는 간략화된 방법을 제시하였다. 제안된 방법은 화재강도 즉, 화재 중 최고노출 온도 뿐 아니라 화재지속시간도 고려할 수 있도록 하였다. 제안된 방법의 검증 및 비교를 위하여 화해를 입은 대구지하철 역사의 현장조사 결과를 인용하였으며, 해석결과 그 효용성을 확인하였다.

• 한국물환경학회지
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• 제33권6호
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• pp.650-660
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• 2017

In this study, pollutant emission characteristics by water damage period analyzed 11 items (water temperature, pH, DO, EC, BOD, COD, TOC, SS, T-N, T-P and flow) with load duration curve, time series load curve and factor analysis for three years (2014-2016). Load duration curve is applied to judge the level of impaired waterbody and estimate impaired level by pollutants such as BOD and T-P in this study depending on variation of stream flow. Water quality standard exceeded the flow of mid-range and low-range by flow condition evaluation using load duration curve. This watershed was influenced by point source more than non-point source. Cumulative excess rate of BOD and T-P kept water quality standard for all seasons (spring, summer, autumn and winter) except BOD 59% in spring. Water quality changes were influenced by pollutants of basic environmental treatment facilities and agricultural areas during spring and summer. Results of factor analysis were classified commonly first factor (BOD, COD, and TOC) and second factor (flow, water temperature and SS). Therefore, effects of artificial pollutants and maintenance water must be controlled seasonally and reduced relative to water damage caused by point pollution sources with effluent standard strengthened in the target watershed.