Two-Scale Topology Optimization of the 3D Plant-Inspired Adaptive Cellular Structures for Morphing Applications

A novel two-scale topology optimization method is developed in this work to optimize three-dimensional (3D) plant-inspired fluidic adaptive cellular structures for morphing applications. In this method, the coupled mechanical behaviors of the 3D smart structures with fluidic cells are simulated by extended multiscale finite-element method. Multiscale base functions are constructed through the microscale computation to create the relationship between information of the single cells in the microscale and structural deformation in the macroscale. Furthermore, the 3D structural topology algorithm based on the power-low interpolation approach is combined with the multiscale method to improve the mechanical behaviors of the plant-inspired cellular structures. Consequently, the plant-inspired cellular structures can be designed by the proposed optimization method, in which the distribution of the motor cells is optimized to maximize the structural performance. Then, the smart structures based on fluid actuation of the cells can be optimized to create biomimetic compliant mechanisms, where self-actuated output displacements are set as the design objective. Moreover, the proposed two-scale optimization algorithm is investigated to optimize the number of liquid motor cells in order to minimize the weight of the cellular structure. Numerical examples including the design problems of morphing wings indicated that the two-scale topology optimization method can be effectively used to design the 3D plant-inspired cellular structures.