Abstract:

Based on studying the constitution of yarn system and the geometric modality of relevant yarns in the multi-axial warp-knitted structure, 3D solid models of the loop yarns, insertion yarns and chopped strand mat in modern multi-axial warp-knitted fabrics were built to reflect the geometric structures of the three items by using NURBS curves and the principle of curved surfaces. Besides, OpenGL was employed to explore the corresponding 3D computer simulation system under the condition of VC++.NET, which could simulate the geometric model of multi-axial warp-knitted fabric. Meanwhile, through the selection of the unit cell of the fabric, the unit cell model of modern multi-axial warp-knitted fabric with chopped strand mat was developed and the relation between geometric parameters and process variables was deduced. The theoretical fibre volume fraction formula of modern multi-axial warp-knitted fabric with chopped strand mat was obtained as well. Furthermore, by using different specifications of fabric as samples, theoretical and experimental values of the fibre volume fraction were compared. The results revealed that there was good agreement between the theoretical and experimental values, which proved that the model was scientific and practical.