Session: 17-01-01: Research Posters

Paper Number: 151648

151648 - Coupled Topology Optimization and Path Planning in Continuous Fiber Composites 

Continuous fiber additive manufacturing and tow steering technologies, such as Automated Fiber Placement (AFP), allow for laying fiber, yarn, or tow strips along curvilinear paths over complex 3D surfaces, resulting in lightweight and high performance composite laminates.However, one of the significant challenges in the design of continuous fiber-reinforced composites, e.g. additively manufactured or tow-steered fiber composites, is the periodic behavior of fiber orientations, which leads to discontinuities in fiber orientation filtering and inaccurate assessments of manufacturing constraints.

This work addresses this issue by introducing a novel path planning constraint that captures gaps and overlaps in the fiber paths at every design point, while accounting for the bidirectional properties of orientation design variables. To improve numerical robustness and design manufacturability of topology optimized designs, these constraints are integrated into a comprehensive robust design framework that combines topology optimization with fiber path planning. The resulting problem is solved by the Method of Moving Asymptotes(MMA) with the large numbers of path planning constraints efficiently handled using the Augmented Lagrangian method, providing a robust solution for managing fiber orientation and material distribution simultaneously. The proposed methodology is demonstrated through benchmark minimum compliance problems applied to single-ply and multi-ply composite laminated structures, including an L-bracket, a cantilever beam, and a clamped plate. The L-bracket and the cantilever beam are modelled with plane stress assumptions and are discretized by standard four-node bi-linear quadrilateral elements, while the clamped plate is modeled by 3D nine-node shell elements with five degrees of freedom per node that was especially developed for laminated composite shell structures.

Numerical results show that the optimized designs are both structurally efficient and manufacturable, achieving high stiffness and low weight while ensuring continuity in fiber paths. The proposed method significantly reduces fiber path gaps and overlaps and enforces topology control on the minimum length scales of solids and voids, making it particularly effective for designing manufacturable composites. As the path planning constraint limits decrease, both the optimized topology and the fiber paths vary, indicating the complexity coupling between fiber orientations and topological changes.

In conclusion, this work offers an advanced solution to one of the critical challenges in composite design, providing a unified approach that enhances both performance and manufacturability. The framework presented here holds significant potential for practical applications in the design and fabrication of fiber-reinforced composites, particularly in additive manufacturing and tow-steering processes. Furthermore, the proposed path planning constraints also apply to additive manufacturing of isotropic materials, where interlayer and intralayer anisotropy is often introduced due to  material deposition, and gap/overlap between deposition paths should be avoided.

Presenting Author: Chuan Luo Columbia University

Presenting Author Biography: Dr. Chuan Luo is currently a postdoctoral research scientist at Columbia University Medical Center, and earned his PhD from the Department of Civil and Systems Engineering at Johns Hopkins University in 2023. His research expertise is in engineering design, computation, and optimization, with a particular focus on computational design for advanced structures and manufacturing.

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