Automatic Ply Partitioning for Laminar Composite Process Planning

TL;DR

The paper tackles the challenge of partitioning large laminar composite plies into manufacturable sub-plies under prepreg spool width constraints. It introduces an automated ply partitioning framework that treats seam placement as a sequence of linear programming problems, augmented with constraints for overlaps, stay-out zones, ply quality, and cutting patterns; greedy local optimization is shown to be as effective as a beam-search global approach for the tested scenarios. The approach supports cost- and fidelity-aware design exploration and can be integrated into existing design workflows, as demonstrated on wing and armored-vehicle panels. The results demonstrate efficient computation (seconds per case) and robust handling of manufacturing constraints, enabling scalable, automated planning without extensive trial-and-error.

Abstract

This work introduces an automated ply partitioning strategy for large-scale laminar composite manufacturing. It specifically targets the problem of fabricating large plies from available spooled materials, while minimizing the adverse effects on part quality. The proposed method inserts fiber-aligned seams sequentially until each resulting sub-ply can be manufactured from available materials, while simultaneously enforcing constraints to avoid quality issues induced by the stacking of seams across multiple plies. Leveraging the developable nature of individual plies, the partitioning problem is cast as a sequence of one-dimensional piecewise linear optimization problems, thus allowing for efficient local optimization via linear programming. We experimentally demonstrate that coupling the local search with a greedy global search produces the same results as an exhaustive search. The resulting automated method provides an efficient and robust alternative to the existing trial-and-error approach, and can be readily integrated into state-of-the-art composite design workflows. In addition, this formulation enables the inclusion of common constraints regarding laminate thickness tolerance, sub-ply geometry, stay-out zones, material wastage, etc. The efficacy of the proposed method is demonstrated through its application to the surface of an airplane wing and to the body panels of an armored vehicle, each subject to various performance and manufacturing-related geometric constraints.

Figures (19)

• Figure 1: Laminar composite elements: Prepreg ply, composed for matrix-embedded unidirectional fibers is layered in specific orientations during layup to form a laminate with a desired shape and mechanical properties.
• Figure 2: Design pipeline: Part geometry and composite properties are defined in the engineering design stage. The part is partitioned into flattenable regions and detailed ply designs are generated for each region in the detailed ply design stage.
• Figure 3: Prepreg spool illustration.
• Figure 4: Manual partitioning operation sequence beginning from a spool width-driven pattern, and correcting issues sequentially until a viable design is found.
• Figure 5: Example partitioned ply and key terminology. The 2D flattened ply representation is divided along straight seams in the fiber direction. Overlaps extend each resulting sub-ply symmetrically about the seam. Seams are defined in terms of their offset from a ply-specific origin.