Manufacturing-oriented topological design of CFRC structures with variable fiber volume and orientation

Abstract

Allowing freely steering fiber orientation, curvilinear fiber reinforced composite has much better load-bearing capacities than conventional straight-fiber composites. However, the uneven distribution of the fiber and the manufacturability are often ignored while designing variable stiffness composite structures. In this paper, a manufacturing-oriented topology optimization method is proposed for designing continuous fiber reinforced composite (CFRC) structures, in which the fiber content as well as the fiber orientation are concurrently optimized with topology variables. The smooth design with explicit boundary is achieved by the floating projection topology optimization (FPTO) method, in which the implicit floating projection constraint is employed to simulate 0/1 constraints of topology design variables. In order to improve the manufacturability of the design, the fiber placement path fitting method based on the potential flow theory is proposed and embedded in the optimization procedure. By analogy with the streamlines, the fiber path would be placed continuously without any crossing and overlap, meanwhile the fiber content could be adjusted optimally according to the stress distribution. Numerical examples are presented to demonstrate the effectiveness of the proposed method.