Effect of orthotropy and printing patterns on the bending performance of 3D printed concrete grid components

This study systematically investigates the bending performance of 3D printed concrete (3DPC) grid components, focusing on the synergistic effects of printing patterns and interfacial anisotropy. Experimental and numerical analyses were conducted on W- and Y-grid specimens fabricated with 10 mm and 20 mm nozzles. A refined finite element model (RFEM) integrating plastic damage elements for filaments and bilinear cohesive zone models (CZM) for interfaces was developed. Key findings reveal that Y-grid components exhibit 80% higher load-bearing capacity than W-grid counterparts, attributed to enhanced node strength, uniform stress distribution, and increased moment of inertia. Smaller nozzles improve mechanical performance by reducing interfacial defects, with 10 mm nozzles increasing ultimate loads by 10–24% compared to 20 mm nozzles. Crucially, interfacial damage remained absent prior to structural failure, demonstrating that optimized printing patterns can mitigate anisotropy effects. The validated RFEM achieved less than 10% error in predicting failure loads and displacements, confirming its utility for 3DPC design. This work advances the understanding of pattern-driven structural optimization in additive manufacturing and provides a computational framework for performance prediction.