Optimizing in-plane strength of honeycomb structures to achieve quasi-isotropic performance
Khalid Alblalaihid, Saad Aldoihi, Safwan Alblihed, Hani Algaan, Sami S. Alsaleh, Basheer A. Alshammari, Ibrahim A. Alshunaifi, Anas A. Almuqhim, Khalid Khormi, Meshal Abuobaid, Abdulmalik Alshamikh
Abstract
• A novel orientation strategy based on the [±45°, 90°, 0°] stacking sequence is applied to 3D-printed honeycomb structures, inspired by classical laminate theory. • The approach successfully achieves quasi-isotropic in-plane mechanical behavior in short carbon fiber-reinforced PA6 lattices fabricated via FFF. • Tensile and compression tests demonstrate less than 3% variation in elastic modulus across 0°, 45°, and 90° orientations • In-plane compression testing reveals enhanced energy absorption, a flatter stress plateau, and reduced stress drop ratio, validating the design’s performance under multi-axial loading. Honeycomb structures are widely employed in aerospace, automotive, and engineering applications due to their excellent strength-to-weight ratio. However, conventional honeycomb designs—particularly those fabricated via 3D printing—often suffer from pronounced in-plane anisotropy, which limits their mechanical performance under multi-directional loading. This study introduces a modified honeycomb design aimed at achieving quasi-isotropic in-plane behavior. Using fused filament fabrication (FFF) with polyamide 6 (PA6) reinforced with 15 % short carbon fibers, honeycomb structures were fabricated with a [±45°, 90°, 0°]s layer orientation. Experimental tensile tests and finite element analysis (FEA) demonstrated a significant reduction in anisotropy, with elastic modulus variation across 0°, 45°, and 90° directions reduced to under 3 %. In-plane compression tests further validated the design, revealing modulus variation below 2 % and a flatter, more stable stress plateau. This behavior confirms enhanced progressive collapse and improved energy absorption compared to conventional honeycomb structures.