계면이 분리된 복합재료의 기계적 성질 연구

Abstract

취성기지 복합재료는 섬유와 기지 사이에 층간 비접착을 보이는 경우가 있는데 이것은 복합적층판의 강도 및 강성 저하를 초래하게 된다. 본 연구에서는 유한요소법을 사용하여 복합재료의 기계적 성질에 미치는 비접착과 섬유체적비의 영향을 고찰하였다. 우선 몇 가지 가정 하에 복합재료를 구성하는 섬유와 기지의 형상을 단순화하였고 이웃하는 대표체적요소의 경계를 따라 응력과 변위의 연속조건을 부과하였다. 비접착을 갖는 복합적층판의 탄성계수와 포와송비를 구하기 위하여 강성상수들을 역변환하였다. 수치해석 결과를 혼합법칙 결과와 비교한 결과 일치함을 알 수 있었다. 섬유체적비가 증가함에도 불구하고 비접착각도가 증가하면 기계적 성질이 감소함을 알 수 있었다.

Brittle matrix composites often have interfacial debonding between the fiber and matrix which may lead to strength and stiffness degradation. The effects of interfacial debonding and fiber volume fraction on the mechanical properties of composite material were studied by using finite element method. Firstly, the modelling of fibers and matrix constituting the composite material was simplified under some assumptions. Traction and displacement continuity conditions were imposed along the boundary of adjacent representative volume elements. In order to obtain the elastic moduli of composite material, stiffness constants were inverted. Numerical values of elastic moduli were compared with theoretical values obtained by using rule of mixture. Material properties were found to decrease as the debonding angle increased even though the fiber volume fraction increased.

Brittle matrix composites often have interfacial debonding between the fiber and matrix which may lead to strength and stiffness degradation. The effects of interfacial debonding and fiber volume fraction on the mechanical properties of composite material were studied by using finite element method. Firstly, the modelling of fibers and matrix constituting the composite material was simplified under some assumptions. Traction and displacement continuity conditions were imposed along the boundary of adjacent representative volume elements. In order to obtain the elastic moduli of composite material, stiffness constants were inverted. Numerical values of elastic moduli were compared with theoretical values obtained by using rule of mixture. Material properties were found to decrease as the debonding angle increased even though the fiber volume fraction increased.