Effect of fiber misorientation on the tensile strength of compression molded continuous fiber composites

Resin cross-flow during compression molding of unidirectional sheet molding compound composites, such as CSMC and XMC, may cause severe misorientation of the continuous fibers in the outer layers. The extent of fiber misorientation depends on the type of molding compound, the length of cross-flow, and the location of the charge in the mold. The tensile strength is reduced in the direction of cross-flow with decreasing mold surface coverage. However, since severe fiber misorientation is generally restricted to the outer layers, increasing the number of plies improves the tensile strength to the level observed with little or no misorientation.