This paper is concerned with the effect of filler to a crack which, has occurred in the polymer composite materials under loading. Model specimens for photoelastic test were made with epoxy resin plate in which a small copper plate was inserted as a filler into central transverse axis, and varied the length of copper plate from 0 to 80mm. Measurement of stress concentration factor of simple epoxy plate was carried out under tension, bending and bi-axial loading respectively, according to the variation of depth, angle and root radius of notch. And it was then compared to stress concentration factor of a specimen notched in the same way in which a copper plate was inserted. The results showed that under tension the values of stress concentration factor of copper plate inserted specimen were lower than un-inserted epoxy plate, but under bending the values were represented reversely owing to the position of copper plate in specimen. In bi-axial loading the values were observed to be between the values under tension and under bending.

하중을 받고 있는 복합재에서 crack에 대한 충전재의 영향을 광탄성학적 방법으로 고찰하였다. 중심축상에 충전재로서 동판을 삽입한 epoxy 수지 시험편을 제작하고, 동판의 길이 변화, notch의 깊이 변화 및 notch의 선단반경 변화에 따른 notch 부위의 응력집중계수의 변화를 측정하였다. 인장하중을 가했을 때 응력집중계수는 충전재의 영향으로 낮은 값을 나타냈으며, 중전재의 길이가 길어짐에 따라 현저하게 감소하였으나, 굽힘하중하에서는 삽입위치에 의해 오히려 증가하였다. 인장과 굽힘하중을 동시에 가한 이축하중하에서는 인장하중에 의한 응력상태와 굽힘하중에 의한 응력상태가 중첩되어 나타나는 것을 알 수 있었다.

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