Design of Three-Dimensional Functionally Graded Composite Structures to Maximize Stiffness and Natural Frequency

This study proposes a design methodology for three-dimensional functionally graded composite structures (FGCSs) by integrating the concept of functionally graded materials (FGMs) with a topology optimization framework.For the design of multiscale composite structures, anisotropic material properties are evaluated using a representative volume element (RVE)-based machine learning module, combined with rotation matrix calculations based on unit quaternions.In addition, a multi-objective optimization is performed with structural stiffness and natural frequency as objective functions to evaluate the optimized structural configurations and their performance under diverse physical environments.The proposed approach enables systematic design of FGCSs with enhanced stiffness and dynamic characteristics.