Prediction of Flexural Properties of Additively Manufactured Short Fiber-Reinforced Polymer Composite Parts

Fibre-reinforced polymer (FRP) composites have many desirable properties such as high corrosion resistance and a high strength-to-weight ratio. They can also be easily optimised to suit different loading requirements. To produce functional components through 3D printing using FRPs, it is important to optimize the printing process parameters and to predict the mechanical properties of the printed components. The mathematical predictive approach is preferred over experiments it is flexible, fast and not as costly as experiments. In this work, a coupled finite element model for predicting flexural strength properties of additively manufactured parts is developed. The model takes into account the structure, material microstructure, and fused filament fabrication (FFF) process parameters in predicting the flexural strength of parts. The validity of the model is tested using a standard flexural bending specimen and an ankle-foot orthosis (AFO) prototype which are fabricated using short carbon fibre-reinforced polyamide 12 (PA12-CF) filament. The validity of the coupled analysis model was tested by comparing the model predictions of flexural strength with experimental results. The results provide a good prediction of part performance.