Optimization of fiber orientation and topology for curved-folded laminated bamboo veneer shells

Laminated natural materials, exemplified by laminated bamboo veneers, have been extensively used in architectural and engineering applications due to their cost-effectiveness, outstanding toughness, and sustainable characteristics. However, conventional applications of laminated bamboo veneers typically exhibit continuous surfaces with parallel or orthogonal fiber orientations. Given the anisotropic properties and manufacturability of bamboo veneers, there is significant potential to optimize fiber orientations for laminated bamboo veneers while simultaneously reducing structural weight through topology optimization. The foldability of thin bamboo veneers can also be leveraged to improve structural performance while reducing manufacturing costs. This paper presents an innovative coupled optimization approach specifically designed for laminated natural composites in curved folded configurations. The approach integrates concurrent optimization of local fiber orientation and global structural topology by incorporating developable surface parameterization, principal stress alignment, and bi-directional evolutionary structural optimization. Two distinct filtering schemes are proposed to meet different design specifications across the laminated plies. Results from numerical analyses demonstrate that substantial compliance and weight reductions can be achieved by using the proposed approach. To further facilitate assembly and fabrication, member connections within each bamboo veneer patch are realized with minimal material usage. By maximizing the structural contribution of bamboo veneer fibers and reducing weight through the removal of inefficient materials, the proposed approach expands the potential of laminated natural fiber materials in sustainable fabrication practices. • An approach is developed to optimize the fiber orientation and topology for laminated curved folded bamboo veneer shells. • Strategies for patch division and assembly are proposed to facilitate fabrication. • Two filter schemes are introduced to address different cross-ply-topology requirements for laminated shells. • The proposed approach can produce laminated bamboo veneer shells with reduced compliance and weight, simultaneously.