Manufacturability-Driven Topology Optimization Design Method for Structural Continuous Yarn Polymer Composite Parts

Abstract

Polymer-matrix composites (PMC) are widely used in dynamic applications because of their outstanding specific mechanical properties. PMC manufacturing is inherently additive. However, topology optimization (TO) of PMC parts is limited by challenges in manufacturing irregular lattice geometry parts with continuous yarns extending along 3D paths aligned with local principal stress directions. This work introduces a design method for PMC parts featuring 3D TO, focused on manufacturability using continuous yarns. The outcome of the design method consists in continuous 3D paths for flexible arrays of tensioned collimated yarns wound around curved surface guides located on the periphery of the part envelope, and interlaced with each other within the part envelope. The irregular lattice constitutes the reinforcement of 3D TO PMC parts. The design method features 4 sequential steps: static linear elastic analysis and determination of the principal stress vector field, generation and selection of stress paths, k-neighbours triangulation for lattice generation, and yarn path generation. Collectively, a limited number of yarn paths cover all lattice segments with minimal overlap, entering and exiting the part envelope at points selected to facilitate manufacturing. The design method is illustrated using an asymmetric torsion link demonstrator subjected to tension.