Researcher(s)
- Christopher Segura, Mechanical Engineering, University of Delaware
Faculty Mentor(s)
- Suresh Advani, Mechanical Engineering, University of Delaware
Abstract
Composite research is seeing increasing sophistication in its use of additive manufacturing techniques, particularly in 3D printing technologies that utilize continuous fibers dispersed in thermoplastics. 3D printing offers many unique advantages: it minimizes waste materials, facilitates high-precision parts, and allows for geometries that would otherwise be unattainable. Thermosets, due to crosslinking, possess enhanced mechanical properties, such as higher ultimate strengths and rigidity, and have higher melting points compared to their thermoplastic counterparts, making them ideal for high-performance applications. Despite the rapid headway being made in other areas of additive manufacturing techniques, however, the use of continuous fiber composites using thermosets remains in its infancy due to difficulties in curing.
This study explored how varying compaction pressures (0, 100, and 200 kPa) and epoxy-UV resin mixtures (0%, 25%, and 75% mass percentages) influence the consolidation of annular carbon fiber parts. Our primary goal was to understand their impact on fiber-epoxy impregnation and void reduction, both critical for the mechanical properties of composites. We incorporated UV resin to assess whether partial curing could enhance consolidation before the final oven curing.
Results showed that increased pressure effectively reduced part thickness. However, higher UV resin content led to greater deviations in thickness measurements, due to aggressive crosslinking from the thermal initiator added to ensure complete curing of the UV resin. A MATLAB script calculated the fiber volume fraction (FVF), revealing unanticipated correlation between the various configurations and their respective FVF. We attributed this to irregularities stemming from differential in the UV and epoxy contraction. After micro-CT analysis accounted for void content, a clearer trend emerged between viscosity and theoretical FVF, aligning more consistently with physical models. Notably, the least viscous mixture proved most sensitive to compaction. Future work will investigate additional configurations and varying UV cure times to further optimize consolidation.