Anisotropic mechanical property simulation of fiber reinforced PEEK using composite theory and comparison to experimental results

The mechanical properties of 3D printed composites have been shown to vary due to the manufacturing infill direction due to artifacts from the printing process. PEEK (Polyether Ether Ketone) and PEEK reinforced with carbon fiber were studied for these experiments because they are widely used for their high strength properties. 3D printed composites that behave with anisotropic characteristics have been evaluated under Laminate Composite Theory (LCT), which can be used to determine the mechanical properties of these 3D printed composites. By changing the orientation of the extruded strands in a 3D printed part, the structure can be optimized in a specific orientation for specific loading conditions, and LCT can be applied for simulating mechanical responses. Three point bending tests were performed on rectangular 3D printed samples and compared to a 3D simulation using LCT for a similar bending load. This allows for the use of LCT in combination with a finite element software such as ANSYS to optimize the design of the 3D printed composite for specific loading conditions without the need of destructive testing. This approach can save time and materials if the simulation testing is proven to be consistent and has been verified using three point bending experimental results. The analysis of the experimental data found that the orientation of the stacking sequence caused a change in the flexural modulus with a maximum percentage difference of 177.63% for the carbon fiber reinforced PEEK and 5.85% for the regular PEEK. Tabular data and plots were created to compare the accuracy of the simulation data with the experimental results. The simulation used LCT to predict a modulus that was compared to the modulus of the recorded data. This was done to compare and confirm the accuracy of the simulation using LCT, the results showed that the largest percentage difference for PEEK CF is 7.774% in the 60 degree orientation and for PEEK the largest difference is 3.166% in the 30 degree orientation. The results show that a product can be printed in an orientation to improve mechanical properties of 3D printed parts with known loading conditions and allow for design and optimization using LCT.