Acoustic-assisted DLP 3D printing process for carbon nanofiber reinforced honeycomb structures

Fiber-reinforced composites, consisting of robust fibrous constituents and a resin matrix , have received considerable attention due to their superior mechanical properties, corrosion resistance and thermal endurance characteristics. Incorporating with honeycomb structure , a notable subset of porous structures can further reduce the weight of composites and maintain superior mechanical performance. However, fabricating fiber-reinforced honeycomb structures remains technically challenging. Herein, we proposed a novel standing surface acoustic waves (SSAWs) assisted digital light processing (DLP) 3D printing method for fabricating carbon nanofiber-reinforced honeycomb structures. An acoustic-assisted printing system was developed, and the working principle of using SSAWs for fiber-reinforced structures printing was investigated. With the assistance of the generated acoustic pressure fields induced by SSAWs, carbon nanofibers can be arranged into a strip-like pattern and thereby be cured within honeycomb structure by photocuring process. The compression tests are performed, and results demonstrated that the printed fiber-reinforced composites have low surface roughness and high printing accuracy. Additionally, compared to pure resin structures, there are approximately 18.1 % and 7.9 % improvements of ultimate stress and energy absorption of fiber-reinforced honeycomb, while randomly distributed nanofiber reduces the ultimate stress by 9.7 % compared to the pure resin structure. Thus, this study validates the ability of using acoustic-assisted printing method to fabricate fiber-reinforced honeycomb structures.