Simulation-Oriented Rule-Driven Geometric Modeling of Polymer-Fiber Weft-Knitted Structures for Moisture-Transfer Prediction.

Polymer-fiber weft-knitted textiles are widely used in functional apparel and moisture-management materials, but their complex loop topology, yarn-level porosity, and interlayer hierarchy make simulation-oriented geometric modeling challenging. Conventional control-point and interpolated-curve methods often have limitations in representing knitting actions, maintaining yarn-path continuity, and generating meshable geometries. This study proposes a rule-driven geometric modeling method for polymer-fiber weft-knitted structures using the yarn centerline as the basic geometric carrier. Knitting actions, including knit, tuck, float, plating, and double-needle-bed assignment, are converted into reusable local path-generation rules and integrated through pattern-matrix input, action recognition, parametric centerline generation, continuous stitching, and standardized output. The method represents single-bed and double-bed structures within a unified framework, including plain, jacquard, plated, tuck, rib, interlock, half-cardigan, full-cardigan, and purl structures. Compared with an interpolated-curve method, the curvature-jump rate of four representative structures decreases from 40.78-69.23% to 0-0.31%, with markedly reduced maximum bending angles. Mesh-generation results show continuous meshes with improved element quality for complex double-bed structures. A moisture-transfer simulation of a fully plated plain-knitted structure gives one-way transport indices of -122.3187 and 122.2472 for face- and back-side liquid entry, with relative errors of 1.74% and 0.50% compared with experiments. These results indicate that the proposed method provides reproducible and meshable geometric input for structure-property modeling and moisture-transfer prediction of polymer-fiber knitted textiles.