3D printing of curvilinear fiber reinforced variable stiffness composite structures: A review

Curvilinear fiber reinforced variable stiffness structures (CFRVSSs) can be designed by adjusting the local fiber orientation and content to maximize the performance advantages of continuous fibers, which have potential application prospects in aerospace and other fields. The continuous fiber reinforced composites (CFRCs) 3D printing process can accurately regulate the fiber content and fiber orientation by planning the printing path and designing the process parameters, which provides the possibility of integrated mold-free fabrication of CFRVSSs. In recent years, it has become a research hotspot. Therefore, the current state of research on the 3D printing of CFRVSSs is reviewed in this paper. First, the modeling methods of the 3D printing of CFRVSSs are introduced. Then the main design methods of CFRVSSs are summarized, the 3D printing process of CFRVSSs and the optimization of their forming defects are introduced, and research work on 4D printing of advanced composite variable stiffness smart structures is summarized. Finally, the future research directions are presented to guide the development and application of 3D printing of CFRVSSs.