Heuristic Optimization Method for Cellular Structure Design of Light Weight Components

Additive manufacturing can be used to produce structures which would be impossible to manufacture using traditional manufacturing processes. One application of this technology is for fabrication of customized, light-weight material called meso-scale lattice structure (MSLS), which is a type of cellular structure with dimensions in the range of 0.1 to 10 mm. The problem to be addressed in this paper is how to efficiently synthesize MSLS with thousands of struts and, hence, thousands of design variables. A heuristic optimization method is presented for efficiently synthesizing large MSLS on complex shaped parts that reduces the multivariate optimization problem to a problem of only two variables. The heuristic is based on the observation that the stress distribution in a MSLS will be similar to the stress distribution in a solid body of the same overall shape. Based on local stress states, unit cells from a predefined unit-cell library are selected and sized to support those stress states. In this paper, the method is applied to design a strong, stiff and light-weight Micro Air Vehicle fuselage. Weight savings are demonstrated as a result.