Bending and failure behavior of 3D printed continuous fiber reinforcement composite corrugated sandwich structures: Experimental and numerical investigation

A composite corrugated sandwich structure fabricated using composite fiber co-extrusion two-matrix 3D printing (3DP) technology is proposed. Compared to other processes, continuous fiber 3DP allows for the formation of a single integral piece, resulting in exceptionally high strength and ductility of connection between face and core. The bending performance of the structure was investigated, revealing its excellent bending energy absorption characteristics. Given the complexity of fiber distribution in continuous fiber 3DP, which exceeds that of traditional laminated continuous fiber structures and exhibits non-uniform mechanical characteristics, the conventional finite element modeling method is no longer adequate. Therefore, we propose a multi-scale FE calculation model based on Representative Volume Elements. After experimental validation, this model demonstrates high accuracy in predicting the peak load, the deformation stage preceding the peak load, and the failure deformation shape. Utilizing this model, the analysis of path stress distribution and parameter influence is conducted, which elucidates the internal cause of structural failure progression. In the parameter influence analysis, it was found that the thickness of the face plate has the most significant impact on the structural bearing capacity, with the potential to increase the maximum peak load by 65.9% without increasing the fiber content.