A concurrent optimization framework for composite structures: Integrating topology and continuous fiber path design under manufacturing and strength constraints

Continuous fiber-reinforced composites (CFRCs) offer transformative lightweight potential through curvilinear fiber paths, yet reconciling structural performance with manufacturing feasibility and strength remains challenging. This study presents a concurrent optimization framework for CFRCs structures integrating topology design and curved fiber path optimization under manufacturing and strength constraints. A unified parametric model using spatially correlated random fields defines both structural topology and fiber paths, enabling precise control over local fiber orientation and content distribution. Variable fiber content is achieved via controlled inter-tow spacing within contour-aligned paths. Manufacturability constraints are enforced via maximum curvature limits to prevent printing defects, while strength constraints are rigorously satisfied using the Tsai-Wu failure criterion within the optimization loop. The framework maximizes structural stiffness using an augmented Lagrangian (AL) method to handle constraints and the method of moving asymptotes (MMA) for resolution. Numerical results demonstrate significantly higher stiffness than conventional uniform fiber layouts while strictly adhering to manufacturing and strength limits. This research establishes a direct pathway from physics-based design to additive manufacturing, combining fundamental constraints with production needs through experimental material modeling and variable fiber content path planning.