ANALYSIS OF THE AERODYNAMIC PERFORMANCE OF CARBON FIBER WINGS FABRICATED USING 3D PRINTED MOLDS WITH VARIED SURFACE FINISHES

Abstract

This thesis investigates the aerodynamic impact of surface roughness in carbon fiber reinforced polymer (CFRP) wing skins fabricated using 3D-printed molds. Additive manufacturing via fused deposition modeling (FDM) offers a low-cost method for producing custom molds but often introduces surface imperfections that transfer to the final CFRP part. Mold surface quality is critical for airfoils, where roughness can alter boundary layer behavior. Three mold surface conditions—unsanded, sanded, and coated—were used to produce CFRP wing skins with varying roughness. Surface roughness was measured using a stylus profilometer and quantified through Ra, Rz, and RSm. Wing skins were fabricated using a wet layup process with vacuum bagging at room temperature. Wing skin roughness was then measured to assess fidelity to the mold. Using these values, computational fluid dynamics (CFD) simulations in ANSYS Fluent evaluated aerodynamic performance at Reynolds numbers of 300,000, 3,100,000, and 5,400,000. Higher surface roughness caused earlier boundary layer transition, increased drag, and reduced lift. The coated mold produced the smoothest surface and best aerodynamic results. This study shows that FDM induced surface roughness affects aerodynamic efficiency and emphasizes the value of post-processing in performance-sensitive, low-cost composite manufacturing.