• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.778-783
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• 2001

Turbine blade is subject to cyclic bending force by steam pressure. Stress analysis by fractography is already established technology as means for seeking cause of fracture and has been widely employed. In the X-ray fractography, plastic deformation and residual stress near the fracture surface can by determined and information of internal structure of material can be obtained. Therefore, to find a fracture mechanism of torsion-mounted blade in nuclear power plant, based on the information from the fracture surface obtained by fatigue test, the correlation of X-ray parameter and fracture mechanics parameter was determined and then the load applied to actual broken turbine blade was predicted.

• 대한기계학회논문집A
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• 제26권8호
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• pp.1645-1652
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• 2002

The failure analysis on fractured parts is divided into the qualitative method by naked eyes and metallurgical microscope etc. and the quantitative method by SEM and X-ray diffraction etc. X-ray fractography can be applied to contaminated surface as well as clean surface and gain the plastic deformation and the residual stress near the fractured surface. Turbine blade is subject to cyclic bending force by steam pressure and suffers fatigue damage according to the increasing operating time. Therefore, to clean up the fracture mechanism of torsion-mounted blade in nuclear plant, the fatigue and the X-ray diffraction test was performed on the 12%Cr steel fur turbine blade and the fractured parts. The correlation of X-ray parameter and fracture mechanics parameter was determined, and then the load applied to actual broken turbine blade was predicted. Failure analysis was performed by contact stress analysis and Goodman diagram of torsion-mounted blade.

• 한국정밀공학회지
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• 제19권2호
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• pp.65-71
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• 2002

Turbine blade is subject to cyclic bending force by steam pressure. Stress analysis by fractography is already established technology as means far seeking cause of fracture and has been widely employed. In the X-ray frctography, plastic deformation and residual stress near the fracture surface can be determined and information of internal structure of material can be obtained. Therefore, to find a fracture mechanism of torsion-mounted blade in nuclear power plant, based on the information from the fracture surface obtained by fatigue test, the correlation of X-ray parameter and fracture mechanics parameter was determined and then the stress intensity factor to actual broken turbine blade was predicted.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집A
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• pp.258-265
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• 2001

Turbine blade is subject to force of three type ; torsional force by torsion-mount, centrifugal force by rotation of rotor and cyclic bending force by steam pressure. Cyclic bending force of them is main factor on fatigue fracture. In the X-ray diffraction method, the change in the values related to plastic deformation and residual stress near the fracture surface mat be determined, and information of internal structure of material can be obtained. Therefore, to find a fracture mechanism of torsion-mounted blade in nuclear plant, based on the information from the fracture surface obtained by fatigue test, the correlation of X-ray parameter and fracture mechanics parameter was determined, and then the load applied to actual broken turbine blade parts was predicted. Failure analysis is performed by finite element method and Goodman diagram on torsion-mounted blade.

• 한국해양공학회지
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• 제8권1호
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• pp.114-122
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• 1994

X-ray stress constant, K, was determined for the diffraction line of (211)plane by using Cr-K$\alpha$ radiation. K was -340.87 MPa/deg. Fatigue crack propagation tests of SS41 steel were conducted under stress ratios of 0.1, 0.3 and 0.5. The half-value breadth of X-ray diffraction profile was measured at and beneath the fracture surface. The half-value breadth, B, on the fracture surface was found to increase with increasing $K_max$. The value of B was influenced by stress ratio in SS41 steel. The half-value breadth took the maximum value at the borden of reversed plastic zone, while it approached to the initial (pre-fatigue) value near the boundary of monotonic plastic zone. The maximum depth of the plasticzone was evaluated on the basis of the half-value breadth distribution. The depth $\omega$$_y$ is related to $K_max$by the following equation : $\omega$$_y$ = $\alpha$($K_max$/$\sigma$$_y$$)^2$ where .sigma.$\sigma$$_y$ is the yield strength obtength obtained in tension test .alpha.is 0.136 for SS41 steel.

• 한국광학회지
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• 제13권3호
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• pp.189-196
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• 2002

파장 50 $\AA$ 이하의 연엑스선 영역에서 사용될 평면결상형 연엑스선 분광기의 구성요소와 정렬조건을 결정하고 분광기의 분광학적 특성을 해석하였다. 평면결상형 연엑스선 분광기는 토로이드거울, 실틈, 비등간격 오목에돌이발, 연엑스선 검출기로 구성되어 있다. 토로이드거울과 홈간격이 2400 grooves/mm인 비등간격 오목에돌이발을 사용하여 공간분해된 빛띠가 단일 평면 위에 결상되도록 분광기를 구성하였다. 토로이드거울은 연엑스선 광선이 에돌이발에 비스듬하게 입사할 때 발생되는 비점 수차를 보상하기 위해 사용되었다. 파면수차 이론을 적용하여 분광기가 가지는 파장분해와 공간분해를 계산하고, 에돌이 현상에 대한 스칼라 이론을 적용하여 에돌이발의 에돌이효율을 계산하였다.

• 한국안전학회지
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• 제17권1호
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• pp.18-24
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• 2002

This study verified the relationship between fracture mechanics parameters(${\Delta}K,\;K_{max}$) and X-ray parameters ($(\sigma}_r,;B$) for G365 steel at elevated temperature up to $300{\circ}C$. The fatigue crack propagation test were carried out and X-ray diffraction technique according to crack length direction was applied to fatigue fractured surface. The residual stress on the fracture surface was found to increase in low ${\Delta}K$ region, reach to a maximum value at a certain value of $K_{max}$ or ${\Delta}K$ and then decrease. Residual stress was independent on stress ratio by arrangement of ${\Delta}K$ and half value breadth was independent by the arrangement of $K_{max}$. The equation of ${\sigma}_r-{\Delta}K$ was established by the experimental data. Therefore, fracture mechanics parameters could be estimated by the measurement of X-ray parameters.