Design, manufacturing, and elastic analysis of digital light processing 3D printed fiber reinforced sandwich beams with thermosetting polymer matrix

For the first time, a digital light processing (DLP) three-dimensional (3D) printer is implemented for additive manufacturing of sandwich beams with fiber reinforced facesheets and different core types without using adhesives. After characterizing the formulated thermosetting resin, sandwich beams with honeycomb and square core unit cells were printed in out-of-plane (OP) and in-plane (IP) arrangements, with and without woven glass fiber reinforcement in the facesheets. Meanwhile, using theoretical, micromechanical, and finite element (FE) approaches, the elastic properties and stiffness of sandwich beams were predicted. The stiffness measured from flex tests showed reliable agreement with predictions from analytical and finite element analysis (FEA) for most cases. Additionally, fiber reinforcement significantly increased specific stiffness of these structures, but did not affect the trends for different core geometries. The novel methodology presented here can open new doors for manufacturing advanced structures using DLP 3D printing technology.