A new paradigm in continuous fiber-reinforced polymer fused filament fabrication based on a thermoset-thermoplastic bi-matrix material system is proposed and proved. This totally new 3-D printing concept has the potential to overcome the drawbacks and to combine the advantages of separate thermoset and thermoplastic-based, fused filament fabrication methods and to advance continuous fiber-reinforced polymer 3-D printing toward higher mechanical performances of 3-D printed parts. The novel bi-matrix 3-D printing method and preliminary results related to the 3-D printed composite microstructure and performances are reported.

A model is presented to predict the mechanical hygro-thermo-elastic properties and strength values of composite materials reinforced with plain woven fabric. The laminate properties are calculated from basic constituents properties (fiber and matrix). A three-dimensional geometrical description of the reinforcing architecture is used. The local strain, stress, and constitutive property fields are evaluated under in-plane loading. Multiple modes of failure are monitored and stress redistribution due to progressive failure is evaluated using a novel approach. The model results are compared with experimental data.