Additively Manufactured Lattice Truss Sandwich Cylinder and Free Vibration Behaviors.

In aerospace engineering, it is attractive to combine additive manufacturing (AM) with lightweight design to reduce the weight of primary load-bearing structures. In this paper, a double-layer pyramidal lattice truss sandwich cylinder was designed and printed by selective laser melting (SLM) method, which has advantages in integrally manufacturing end frames and bolt holes. With diameter of 0.493 m, this cylinder is one of the lattice truss sandwich structures with the largest diameter at present. Free vibration testing was carried out to reveal the free vibration responses of the cylinder. The first-order vibration turns from a circle to an oval in the plane of the cross section. The fundamental frequency is 133.9 Hz. An equivalent shell free vibration theory was proposed and finite element models (FEMs) based on discrete model and equivalent shell model were applied to predict the natural frequencies and mode shapes of the cylinder. Advantages of the AM method in making light and stiff large-sized aerospace structures are confirmed through this research. [ABSTRACT FROM AUTHOR]