Compression behavior and energy absorption of 3D printed continuous fiber reinforced composite honeycomb structures with shape memory effects

Three-dimensional (3D) printing is a potential rapid prototyping process that may replace traditional manufacturing processes to fabricate lightweight cellular structures with superior energy absorption performance. In the present work, continuous fiber reinforced composite honeycomb structures (CFRCHSs) with excellent shape memory properties were manufactured through a fused filament fabrication (FFF) technology, and their out-of-plane/in-plane compression behaviors and energy absorption characteristics were experimentally investigated. The results reveal that the failure process of the 3D printed CFRCHSs under in-plane loading is that the honeycomb cells collapse layer by layer along the loading direction，accompanied by the formation of a localized band. The crashworthiness analysis indicates that the 3D printed CFRCHSs outperform several competitive cellular topologies in the compression strength and specific energy absorption. A simplified analytical model for the in-plane compression strength of CFRCHSs was derived, and good agreement between measurements and predictions was observed. Additionally, the shape recovery tests demonstrate that the 3D printed CFRCHSs possess the potential as key elements of lightweight intelligent systems and adjustable energy absorbing devices.