Additively manufactured truss-core sandwich cylinders: Materials, processes and performances

Abstract

To explore a structure with a superior load-to-mass ratio applying in rockets, two types of lattice truss sandwich cylinders with corrugated-core and X-core were designed, printed, tested and analyzed. The powder bed fusion (PBF) technique of laser additive manufacturing (AM) was applied to make the structures. Uniaxial compression results reveal that these truss-core sandwich cylinders have excellent mechanical performances with long plastic deformation, and their ultimate failure modes were global or local plastic post-buckling. The finite element method (FEM) was used to explore the influences of geometrical parameters to the failure mode and the bearing capacity. A failure theory was proposed, which can consistently predict the plastic buckling loads consistent with the experimental results. The load-to-mass ratio of the X-core cylinder is slightly about five percent improved compared to the corrugated-core cylinder, but the plastic plateau stage is greatly increased. Truss-core sandwich cylindrical shell configurations with high load-to-mass ratio, long plastic stage, easy-manufacturing and controllable process were successfully proposed for aeronautical structures through this research.