Abstract
Unidirectional fibrous composites are supposed to give maximum performance under an optimum fiber orientation angle. But the performance is very sensitive to design variables and loading conditions. Therefore, the best configuration under a deterministic condition still has some problems to be solved from a probabilistic viewpoint.
In this paper, a method for evaluating the reliability of unidirectional fibrous composities under probabilistic conditions is proposed, and the effects of various factors on the reliability are investigated. The proposed method is based on a recent structural reliability theory, which is called AFOSM (Advanced First-Order Second-Moment) method. It is found that the proposed method is useful and that the variations of the principal strength, applied stress and orientation angle reduce the reliability. An emphasis is placed on the orientation angle along which the maximum reliability is obtained, and it is found that the optimum angle varies with the variation of the applied stress in some cases.
