전단응력하의 분산형 복합재료에 미시역학적인 특성평가

Analysis for Properties of Particle or Short Fiber Reinforced Composites based on Micromechanics under Pure Shear

  • 조영태 (전주대학교 공업기술연구소) ;
  • 임광희 (우석대학교 반도체전기자동차공학부)
  • 발행 : 2002.06.01

초록

본 연구에서는 분산형 강화복합재료에 균열이 발생하면 하중부하능력이 감소와 더불어 재료의 손상을 초래할 수 있어 재료의 완전한 게재물과 균열이 존재한 게재물이 있는 경우를 상정하여 하중부하능력과 탄성 음력분포를 평가한다. 무한체가 전단음력을 받을 때 완전한 게재물과 균열이 내재한 경우에 대하여 3차원 유한요소해석이 수행되어 완전한 게재물의 경우는 게재물의 영역의 음력은 동일하고 게재물의 계면은 다소 불균일하게 나타났다. 그리고 균열이 내재한 경우에는 균열주변에는 음력이 집중되는 경우를 볼수 있을 뿐만아니라 아주 복잡한 분포를 볼수 있었다. 불균질물의 평균응력은 하중부하능력으로 표현이 가능하였고 완전만 게재물과 균열의 경우도 균열손상에 의해 하중부하능력의 차이를 볼 수 있었다. 특히, 균열이 내재한 경우에 에스펙터비(aspect ratio)가 증가할수록 하중부하능력이 증가함을 알 수 있었다.

Cracking of the reinforcements is a significant damage mode in particle or short-fiber reinforced composites because the broken reinforcements lose load carrying capacity. This paper deals with elastic stress distributions and load carrying capacity of intact and cracked ellipsoidal inhomogeneities. Three dimensional finite element analysis has been carried out on intact and broken ellipsoidal inhomogeneities in all infinite body under pure shear. For the intact inhomogeneity, the stress distribution is uniform in the inhomogeneity and non-uniform in the surrounding matrix. On the other hand, for the broken inhomogeneity, the stress in the region near crack surface is considerably released and the stress distribution becomes more complex. The average stress in the inhomogeneity represents its load carrying capacity, and the difference of average stresses between the intact and broken inhomogeneities indicates the loss of load carrying capacity due to cracking damage. The broken inhomogeneity with higher aspect ratio maintains higher load carrying capacity.

키워드

참고문헌

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