Computational Evaluation of Effects of Fiber Shape on Transverse Properties of Polymer Composites Considering Voids under Dynamic Loading

Mechanical properties of composites are dependent on the constituents' properties and microstructure. To numerically reveal the effects of fiber shape on the transverse dynamic properties of polymer composites, unit cell models considering different fiber shapes are established with the finite-element method and a polymer's rate-dependent behavior is described using the modified Bodner-Partom model. There are some other micro characteristics including fiber distribution patterns and voids that have important influences on composites' transverse behaviors. Models with different regular fiber distribution patterns were analyzed to evaluate the influences of fiber distribution on the response prediction. Then, to evaluate the effects of voids, results from models with different void distribution patterns, void sizes, and void shapes were compared. It shows that among all models established, the highest transverse flow stress value comes from the square-shaped-fiber model without considering the change of fiber cross-section orientation and voids that result in significant reduction in the responses. The flow stress values of most noncircular-fiber models are higher than that of the circular-shaped-fiber model. For each kind of fiber distribution pattern, the flow stress value from the model with square-shaped fibers was the highest. The location, size, modeling method, and shape of the voids affect responses of the models with different fiber shapes to different degrees. (c) 2019 American Society of Civil Engineers.