Thermo-mechanical performance of 3D-printed TC4 hierarchical lattice-truss-core sandwich structures in high temperature conditions

Abstract

Hierarchical lattice-truss-core sandwich structures have attracted increasing attention by virtue of superior performance in both mechanical properties and lightweight hierarchy topology. However, little work has been reported about the thermo-mechanical responses of such emerging structures. In this research, the effects of high temperature on the out-of-plane compressive properties and failure mechanisms of 3D-printed hierarchical lattice structures are experimentally and numerically investigated. Based on a single-stage pyramidal sandwich structure (P), two kinds of sandwich structures consisting of hierarchical pyramidal truss cores are designed: pyramidal-hollow (PH) and pyramidal-cylinder (PC), all kinds of the structures are integrally fabricated by 3D printing technique of titanium alloy (TC4). The thermo-mechanical coupling and responses during compression are experimentally evaluated from 25 °C to a high temperature of 350 °C. The relevant numerical simulations are carried out by finite element analysis (FEA), which are in well agreement with experimental measurements. It is evident that, compared with the single-stage lattice plate with a same weight, the 3D printed PC-1 type hierarchical configuration has a 131.93% increment in the internal heat-transfer area. Meanwhile, it has a 19.31% and a 26.58% increment in bearing capacity at room and high temperature, respectively. The superior integrated load-bearing and heat shielding efficiency are elucidated through the systematical analysis of the influence of hierarchical design on detrimental failure modes under high temperature: buckling and mixed buckling-plastic fracture of the basic and secondary hierarchy. This work could provide a fundamental knowledge for the future design of lightweight structures with thermo-mechanical superiority in high temperature conditions, such as hypersonic flight vehicles scenarios.

Keywords:

• Hierarchical structure
• lattice–truss–core sandwich plates
• thermo-mechanical characteristics
• high-temperature properties
• 3D printing

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Additional information

Funding

This work was supported by China Aviation Science Foundation (grant number: 20200015053004) and China Postdoctoral Science Foundation (grant number: 2021M693007).