Topology optimization of multi-gradient composite

This work presents a computational approach for the design of functionally graded composite with the combination of topology optimization. It is clear that the shell stacking sequence in most exoskeleton sustains their body weight and defends most of the environmental implications. This feature effectively improves the structural robustness in supporting impact waves or defending the failure extensions. Imitate the achievements from bio-inspired laminating, shell is laminated in a coat-base structure and assigned as orthotropic with optimal orientation. Without introducing any new variables, the interpolation model extended from the two-step filter and the multi-gradient topology optimization process precisely defines the location of candidate materials. Besides, another smoothing and projection in the Gradient Norm after the two-step filtration is applied to eliminate the interference of adjacent boundary. Four typical materials are introduced in each layer, and their orientations are optimized by the energy approach at the Base and the gradient approach at the border. We discusses two benchmark problems and an application case in result to demonstrate the effectiveness and orientation independence of the procedure. The optimized structures are evaluated compared to the single-coated result through stress and buckling analysis. The proposed multi-layer composites can be fabricated by filament winding process or hot forming.