Easy manufacturing constraint based topology optimization of dual-scale and dual-constituent lattice metastructure with thermal dimensional stability

Abstract

Thermal dimensional stability (TDS) is a crucial issue in the development of high-end industry equipment and precision instruments that work in fluctuating thermal environments. To endow meta-structures with high load-carrying capacity and TDS functionality simultaneously, this paper proposes a topology optimization framework to optimize the topologies of lattice meta-structures at macroscopic structural and microscopic material scales concurrently. An important feature of the current optimization model is the introduction of a material concentration distribution (MCD) constraint to reduce the number of dual-constituent interfaces (DIs), which enables the easy manufacturing of the optimized structures because an additional fabrication process is required for the connection of heterogeneous lattice members. Designs for two dual-scale TDS structures, potentially employed for satellite payload platforms and the supporting structure of space telescopes, are completed. Compared with mono-scale TDS structures, the dual-scale schemes exhibit superior structural performances due to the opening of the dual-scale design space. Numerical experiments are performed to validate the ultra-low structural thermal deformations of the optimized TDS structures with values of 0.0743 μm/℃ and 0.153 μm/℃. Furthermore, the imposition of the MCD constraint significantly reduces the number of DIs from 38 to 10 within a lattice cell, enabling the easy assembly of the demonstrative 3D printing dual-constituent samples.