Structural design and node shear properties of composite honeycomb cores

As porous biomimetic structures derived from nature, honeycomb structures have attracted considerable attention due to their excellent mechanical properties. Composite honeycomb cores, as key components of sandwich structures, directly determine the reliability and stability of the overall structure. Traditional honeycomb cores lack continuous fiber connections between adjacent cells, resulting in structural weaknesses. Current research has primarily focused on the overall performance of honeycomb sandwich composite structures, leaving a gap in studies on the structural design and process parameter control of the honeycomb core itself, particularly regarding effective testing and characterization methods for its node shear performance. To address these issues, this paper designs two types of layer-to-layer interlocked structures with continuous fiber connections between honeycomb core cells, proposes corresponding test methods for node shear performance, and systematically investigates the influence of fiber architecture on node shear performance. The results show that the stitched honeycomb core exhibits an optimal node shear strength of 13.40 MPa at a stitching distance of 3.0 mm. For the integrally woven honeycomb core, optimal node shear performance is achieved at an interlacing density of 70/cm², with a strength of 18.05 MPa. This study provides key experimental evidence for the structural design and node shear performance optimization of high-performance composite honeycomb cores.