Mathematical Model to Predict the Moduli of Wet-Laid Pulp/Fiber/Resin Composite Materials

In this study, a new wet-laid composite material composed of an aramsid pulp, P-aramid fibers, M-aramid fibers, and a phenol resin has been fabricated to examine the applicability of transmission gears in weight and vibration reduction. Aramid pulps produced via fibrillation on the surface of P-aramid fibers are used to enhance the interfacial bonding between the fibers and resin. Mathematical models to predict the moduli of the wet-laid composite material and a specific relationship between the fibrils and matrix in pulps are additionally proposed. Based on the models, we analyze the variation in the moduli of the composites with two different fiber lengths, when the aramid pulp and P-aramid fiber mass fractions are varied. Moreover, four composite specimens with different phenol and aramid pulp contents (wt%) are fabricated and subjected to tensile tests. The model can well predict the tensile modulus within the error range of the test results. Based on a finite element analysis using the obtained moduli, the soaring out-of-plane stress components at a composite plate edge can be calculated accurately.