Probabilistic Analysis for the Mechanical Properties of Cross-Ply Fiber-Reinforced Composite Laminate

A probabilistic micromechanics model had been developed for the unidirectional fiber-reinforced composite material design screening. In which, we used the predicted mechanical properties of IM-7 carbon fiber from the existing IM-7/5250-4 composite material system together with the observed 977-3 matrix mechanical properties to predict the probability density functions for the mechanical properties of IM-7/977-3 unidirectional composite. To include the material design in the structural design process, we had extended the probabilistic analysis to predict the probability density functions for the off-axis mechanical properties. The angle-ply and cross-ply laminates have been used extensively in aerospace structural designs. It is logical to extend the probabilistic analysis to predict the probability density functions for the mechanical properties of the laminated composite. We had provided the probabilistic analysis for a symmetric regular angle-ply laminate of IM-7/5250-4 composite laminate. In this report, we will focus on the probabilistic analysis of symmetric and anti-symmetric regular cross-ply laminates of IM-7/5250-4 fiber-reinforced composite with odd-number plies parallel to and even-number plies perpendicular to the laminate principal axes. These probabilistic micromechanics models provide a design-screening tool to help material producers to eliminate the unnecessary time-consuming and costly material fabrications and to reduce the numbers of testing to a minimum but enough to verify the model prediction. They also provide a structural analysis tool to help the structural designer to manage the structural and material uncertainties during the structural design process. And consequently, it provides a means to accelerate the insertion of materials into AF productions.