Mathematical and geometric modeling of multi-ply knitted fabrics with multidimensional thermal transfer analysis

Thermal simulation of fabrics has been a focal point of research in recent years. However, in the context of multi-ply knitted fabrics, most studies have remained at the macroscopic level. To explore, evaluate, and optimize new methods for improving the comfort and functionality of multi-ply knitted fabrics, this paper utilizes the finite-element software ANSYS Workbench to simulate the heat transfer performance of fabric systems. The fabric coil structure model is established based on observations and test data of the knitted fabric structure. A general knitted fabric unit cell model is developed, while a systematic helical twisting model for ply cross-sections is introduced at the mesoscopic level to describe the structural morphology of plied yarn twisting in knitted fabrics. To map the yarn morphology onto the coil’s spatial trajectory, an arc mapping control point method is employed, transferring the plied yarn cross-section information onto the coil structure, thereby resulting in the multi-ply twisted knitted fabric model. To validate the model’s reliability in heat transfer performance, simulations are conducted in multiple dimensions: different heating surfaces, different time steps, anisotropy considerations for different plied yarn twists, and comparisons between different models. Using thermal resistance and surface temperature as evaluation criteria, the simulation results are compared with experimental values, and the heat transfer performance of the multi-ply knitted fabric is analyzed.