Simulating performance of tow reinforced hybrid-molded composites

A critical milestone to the adoption of 3D tow reinforced hybrid-molded structures is the development of design guidelines and analysis techniques for accurate performance modelling. The cross-sectional dimensions of the tow bundle leads to fiber length discrepancies between the inner fibers and the outer fibers which manifest as tow spreading and local fiber waviness. The effects of simulating the resulting fiber orientations and effective elastic properties is investigated by modelling a representative beam in tension and bending load cases and comparing to previous experimental results. Accounting for fiber waviness in tension demonstrated greatly improved part stiffness predictions. Spread tow bundles improved predicted strength and stiffness over simulations where tow was constrained to a uniform cross section. Increased tow reinforcement increased bending stiffness, but failure behavior was significantly influenced by the overmolding material.