Effects of Local Fiber Orientation State on Thermal-Mechanical Behaviors of Composite Parts Made by Large Area Polymer Deposition Additive Manufacturing

Short carbon fiber enhances the dimensional stability and material strength of composite parts created via large area polymer deposition additive manufacturing, which has been used for rapid fabrications of large-dimension composite parts and tooling. Nevertheless, the flow-induced fiber orientation formed during the material extrusion and deposition leads the deposited composites exhibit non-homogeneous thermal-mechanical behaviors. This study evaluates the fiber orientation state of a 20 wt.% CF-PEI composite fabricated by polymer deposition using the fully coupled flow/orientation approach. The material properties are computed by considering the deposited bead as heterogeneous segments with different local fiber orientation states. The heterogeneous thermal conductivity and expansion coefficient exhibit maximum local differences of 29% and 21%, respectively. The orientation-homogenized material properties are implemented to the finite element simulation for a large area additive manufacturing process of a single bead and notable differences are seen between results computed by employing the homogenous and heterogeneous properties.