Design for an Additively Manufactured Hollow Glass Microsphere Lattice Support Structure Using Topology Optimization

Abstract For future military mission using high-quality optics to develop remote sensing instruments, it is critical to design a lightweight substrate structure for reliable support to mirrors. This paper proposes a conceptual design methodology for generating a stable and lightweight supporting structure for a satellite mirror substrate using a 3D topology optimized TPMS lattice structure. This lattice would be constructed using 3D printed glass filled with hollow microspheres for further reduced weight while maintaining high rigidity. An optimal 3D topology is generated in MATLAB for maximum stiffness. Using various boundary conditions, multiple TPMS unit cell patterns are produced for comparison. Each unit cell design is used to construct a full assembly and postprocess is followed to eliminate staircases out of topology optimization and smooth the surface profile. Each of assembly is tested in FEM using ANSYS Workbench for stress analysis from vibration and 3-point bending test. A pareto frontier is produced to compare the designs with respect to their loading responses from two tests. This study identifies Schwarz P and N14 as best designs among others. A more realistic assembly with a larger number of unit cells and the corresponding experimental verification is required for detailed performance evaluation for lightweight mirror substrate application.