Three dimensional lightweight lattice structures with large positive, zero and negative thermal expansion

Tailoring thermal expansion of structures is in urgent need in engineering applications where the structures are susceptible to suffer large temperature fluctuation. Here, a method to reconstruct 3D truss structures is developed to obtain large positive, zero and even negative coefficient of thermal expansion (CTE). As the basis, theoretical analysis and numerical verification of the bi-material pyramid and tetrahedron lattice cells explicitly reveal that with thick members, the influence of the cross section on the CTEs should be well considered, and the CTEs should be accurately calculated by the solid model. Furthermore, two kinds of 3D lattice structures with isotropic tailorable CTEs are originally devised. Moreover, bi-pyramid and bi-tetrahedron units are devised, and a reconstruction method, which can reconstruct an arbitrary 3D truss structures to obtain specific target CTE, is originally developed. Typical supporting structure and platform used in satellites are reconstructed by the proposed method, and near zero thermal expansion, which is urgent needed in satellite, can be flexibly obtained. The analysis and proposal of three dimensional lattice structures and reconstruction method provide a new approach to develop structures with light weight and tailorable CTEs.