Analytical and Experimental Study on Fluid-Solid Coupling of Variable-Caliber Nozzles for Concrete 3D Printing

Area of Science:

• Additive Manufacturing
• Materials Science
• Mechanical Engineering

Background:

• Concrete 3D printing (C3DP) offers transformative potential for the construction industry.
• Current C3DP technologies face challenges with geometric accuracy and molding quality, especially for complex curved structures.
• Long motion trajectories of existing nozzles reduce precision in curved component printing.

Purpose of the Study:

• To design an innovative reducer nozzle for concrete 3D printing.
• To shorten the printing stroke and enhance the geometric accuracy of printed components.
• To improve the overall molding quality and surface finish of 3D printed concrete structures.

Main Methods:

• Development of a reducer nozzle featuring multi-gear internal meshing and a rotating blade with adjustable caliber.
• Utilization of fluid-solid coupling analysis to validate the mechanical strength and internal flow field characteristics.
• Experimental comparison of the novel nozzle against existing concrete 3D printing nozzles.

Main Results:

• The variable-caliber nozzle demonstrated a significant improvement in the surface quality of printed specimens.
• The design effectively shortens the printing stroke, leading to enhanced geometric accuracy for curved structures.
• Fluid-solid coupling analysis confirmed the structural integrity and optimized flow dynamics of the nozzle.

Conclusions:

• The proposed reducer nozzle design substantially enhances the precision and quality of concrete 3D printing.
• This advancement addresses key limitations in printing complex curved components.
• The findings strongly support the practical application and further development of C3DP technology in engineering.