An Investigation for Effective Thermal Properties of Titanium Alloy Lattice Sandwich Panels

Multifunctional sandwich panel presents a unique Integrated Thermal Protection System (ITPS) for hypersonic vehicles. In this paper, a novel method to evaluate the effective thermal properties of metal alloy lattice core sandwich panels is presented. The thermal transfer process between lattice core and face sheet was analyzed, and the behavior schemes were detached in three categories according to the existence of insulation material filling and active convection. For each category, equations were presented to calculate the effective density, specific heat and thermal conductivity for pyramid lattice core and tetrahedral lattice core using Representative Volume Element (RVE). Two sandwich panels were constructed separately with the two lattice cores made by the material of titanium alloy. Numerical Simulation based on Finite Element Method (FEM) was employed to verify the effective techniques. Two kinds of FEM models were built with detailed solid element level and simplified effective solid element level. The heat transfer process from top sheet to bottom sheet across lattice core were simulated, consistency of temperature responses could be observed obviously between the different level FEM simulations. It could be concluded that the effective properties deduced with the method in this paper are accurate to predict the thermal performance of titanium alloy lattice core sandwich panels, and are very promising for potential application in the analysis and design of TPS for hypersonic vehicles.