Design and optimization of graded lattice structures with load path-oriented reinforcement

Abstract

Lattice structures have been increasingly used in load-carrying applications due to their exceptional mechanical performance. This study presents a novel load path methodology for designing and optimizing functionally graded lattice structures composed of anisotropic unit cells with directional reinforcement struts. Firstly, the optimal density distribution of the lattice structure is obtained by solid isotropic material with penalization (SIMP) topology optimization. Secondly, pointing stress vectors of the structure are calculated to determine the orientations of the unit cells. Lastly, the lattice model is constructed using tapered beams for a smooth transition between struts with different radii. Two examples of a simply supported beam and a 3-dimensional base support structure are provided. The experimental validation showcases that the proposed design improves the specific stiffness by 75 % compared to the uniform body-centered cubic design. Furthermore, the strength-to-weight ratio is increased by 232 % due to a more desirable stress distribution.