Additive Manufacturing of Continuous Fiber-Reinforced Polymer Composite Sandwich Structures with Multiscale Cellular Cores
Wang Zhen-hu, Yaohui Wang, Jian He, Ke Dong, Guoquan Zhang, Wenhao Li, Yi Xiong
Abstract
The use of composite sandwich structures with cellular cores is prevalent in lightweight designs owing to their superior energy-absorbing abilities. However, current manufacturing processes, such as hot-press molding and mold pressing, require multiple steps and complex tools, thus limiting the exploration of advanced sandwich structure designs. This study reports a novel multi-material additive manufacturing (AM) process that allows the single-step production of continuous fiber-reinforced polymer composite (CFRPC) sandwich structures with multiscale cellular cores. Specifically, the integration of CFRPC-AM and in situ foam AM processes provides effective and efficient fabrication of CFRPC panels and multiscale cellular cores with intricate designs. The cellular core design spans three levels: microcellular, unit-cell, and graded structures. Sandwich structures with a diverse set of unit-cell designs, that is, rhombus, square, honeycomb, and re-entrant honeycomb, were fabricated and their flexural behaviors were studied experimentally. The results showed that the sandwich structure with a rhombus core design possessed the highest flexural stiffness, strength, and specific energy absorption. In addition, the effect of the unit-cell assembly on the flexural performance of the CFRP composite sandwich structure was examined. The proposed design and fabrication methods open new avenues for constructing novel and high-performance CFRPC structures with multiscale cellular cores that cannot be obtained using existing approaches.