• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.66-71
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• 2007

Isochromatics obtained from photoelastic experiment shows the stress distributions of full field of a structure under a load. Therefore stress distributions of the structure can be read at a glace through isochromatics. Many experimental data are obtained from isochromatics. And then, the various photoelastic experimental hybrid methods have been developed. Until now, monochromatic light has been used for photoelastic experimental hybrid method. Therefore the photoelastic experimental hybrid method used until now is called the photoelastic experimental hybrid method for black and white isochromatics. When stresses are analyed by photoelastic experimental hybrid method, many experimental data are needed. Therefore some fringe orders of isochromatics are needed for the photoelastic experimental hybrid method for white and black isochromatics. Therefore in this paper, the photoelastic experimental hybrid method for color isochromatics is developed. In this case, two fringe orders are enough for the experimental data of photoelastic experimental hybrid method for color isochromatics. Applying the method to stress concentration problems, its validity is confirmed. In the precision, the photoelastic experimental hybrid method for color isochromatics is better than the photoelastic experimental hybrid method for white and black isochromatics when fringe orders of isochromatics are few. When fringe orders are few, the photoelastic experimental hybrid method for color isochromatics can be used to analyze stress through few fringe orders of isochromatics.

• 한국해양공학회지
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• 제2권2호
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• pp.96-103
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• 1988

The stress distribution in the vicinity of the crack tip in the fracture mechanics is ordenarily indicated by the stress intensity factor. In the analysis of stress intensity factors, there are many theoretical and experimental methods. The stress analysis in photoelastic technique is usually made by using the difference of the principal stress of isochromatic fringe patterns. In this paper, the teflon molding technique is adopted to make a test specimen with a circular arc-crack, and that upgraded the accuracy of experiment. As the result, the experimental values of the stress intensity factors for the circular disk with a straight crack are coincided with the theoretical values. But, there is quite a difference between this expermental results on the finite plate for circular arc-crack and its theoretical values on the infinite one. Therefore, a boundary condition with regard to the loading condition on finite disk must be considered.

• 대한기계학회논문집A
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• 제28권11호
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• pp.1776-1785
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• 2004

In this research, the relationships between static bimaterial constant and dynamic oscillation index are studied. It was certified that static bimaterial constant has the same form equation as the dynamic oscillation index. Bimaterial constant and oscillation index are increased with the increment of Young's modulus ratio and approached to the some value. Isochromatic fringe patterns are slanted to the left side with increment of bimaterial constants and oscillation index. Though patterns of stress components in above the crack surface are similar to each other, their magnitudes are different a little. In the ahead of crack tip, there are big differences in the isochromatic fringe patterns and their magnitudes. The influence of bimaterial with Young's modulus ratio is bigger in the propagation crack than in the stationary crack.

• 대한기계학회논문집
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• 제16권10호
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• pp.1890-1899
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• 1992

본 연구에서는 이종재료간의 Ⅴ-노치균열의 노치각도 및 재료의 종류에 따른 응력특이성지수와 응력강도 계수 해석에 각각 뉴톤-랍슨법(newtonraphson method), 뉴톤-랍슨법과 최소자승법을 이용한 선점법(collocation method)인 수치해석적 방법을 응용하고, 광탄성 등색선 무늬를 컴퓨터 그래픽하여 응력특이성지수와 응력강도계수가 모우드(mode)에 미치는 특성과 경계요소법(boundary element method)으로 응력해석한 결과로써 선점법을 이용하여 응력강도계수를 해석하고 기존의 결과등과 비교, 검토하 고자 한다.

• 대한치과교정학회지
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• 제34권2호
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• pp.121-129
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• 2004

이 연구의 목적은 세 가지 형태의 헤드기어를 이용하여 상악 제1대구치의 후방이동 시 치아 주위 조직에 나타나는 응력분포를 광탄성법을 이용하여 관찰하는 것이다. 광탄성 상악모형에 장착한 헤드기어에 high-pull, straight-pull, cervical-pull의 세 가지 방향에서, face bow의 inner bow와 outer bow를 평행하게 한 상태에서 outer bow의 길이를 세 가지로 다르게 하여 적용시킨 다음 원편광기를 이용하여 응력분포를 분석하였다. 사진기를 이용하여 응력분포를 기록하고, 등색선상의 무늬차수를 이용, 응력분포를 분석하여 이차원적인 광탄성 응력분석을 시행하였다. 그 결과는 다음과 같다. 1. high-pull 헤드기어의 경우, 중간 길이의 outer bow일 때 치체이동에 유리한 응력 분포가 나타났다 2. straight-pull 헤드기어의 경우, 긴 길이의 outer bow일 때 좀더 치체이동에 유리한 응력 분포가 나타났으나, outer bow의 길이에 따른 응력분포의 변화는 적었다. 3. cervical-pull 헤드기어의 경우, 긴 길이의 outer bow일 때 치체이동에 유리한 응력 분포가 나타났다. 임상에서 헤드기어를 이용하여 상악 제1대구치를 후방으로 치체이동시키기 위해서는 facebow outer bow의 높이를 조정하지 않는 경우에는 high-pull 헤드기어에서는 outer bow와 inner bow를 같은 길이로, straight-pull 및 cervical-pull 헤드기어에서는 outer bow를 더 길게 하여 사용하는 것이 추천된다.