Influence of the Geometric Parameters on the Fiber Stresses in Unidirectional Composites Subject to Transverse Loading

When a unidirectional (UD) composite is subjected to transverse loading, different fibers are not stressed equally. In this paper, realizations of virtual random representative volume element (RVE) and experimental SEM images are translated into finite element models and the average stresses in each fiber are determined. The average stress in individual fibers is correlated with various geometric parameters like nearest neighbor distance, the angle(s) between the nearest neighbor and local fiber volume fraction. A very loose correlation with significant outliers is observed. For the matrix, the region with the highest fiber content does not necessarily lead to the highest matrix stress. The fibers with highest average stresses and the regions with highest matrix stresses are difficult to determine and cannot be simply correlated with geometric parameters.