Lightweight multi-layer graded pyramid folded structure based on tucked kirigami for green manufacturing

Lightweight structures are extensively utilized in various applications that demand exceptional mechanical properties and low densities, such as aerospace, vehicles, and construction components. However, the production of lightweight structures often entails significant material consumption and the emission of pollutants during the pressing and welding processes. Additive manufacturing (AM) has been hailed as a green technology that offers superior flexibility, reduces material wastage, and enables personalized design compared to traditional approaches. In this study, we present a novel lightweight multi-layer graded pyramid folded structure (PFS) based on tucked kirigami, with a focus on green manufacturing principles. The PFSs consist of nested pyramid cells connected by flat triangular plates. By leveraging stereolithography and a two-stage curing process, we achieve AM of multi-layer PFSs with excellent mechanical properties and shaping quality. Experimental studies were conducted on two-dimensional and three-dimensional graded PFSs under lateral and vertical quasi-static compressive loading to investigate the influence of gradient types and values on the mechanical performance of 3D printed PFSs. Our findings reveal that length gradients parallel to the load induce buckling deviations from the center, negatively impacting the performance of single-layer PFSs. Conversely, a height gradient along the zdirection further enhances specific energy absorption (SEA) and compressive strength. The results of this study provide a novel and viable approach to the design and manufacturing of multi-layer graded PFSs with programmable non-uniform stiffness. These graded PFSs hold significant potential for environment-friendly lightweight engineering applications.