Process Design And Finite Element Simulation Of Multi-layer Weft Knitted Fabric With Vertical Braided Sleeve

Multi-layer warp-knitted fabrics can achieve or enhance their functions through structural design.In double-faced warp knitted fabrics,inserting non-knitted warp yarns can increase the number of layers and thickness of the fabric.However,if the inserted middle yarn lacks sufficient grip or has limited grip,it is prone to snagging.In order to effectively improve the anti-snagging and anti-pilling properties of such fabrics,the filling yarns in the middle layer are threaded vertically to form a certain gap length,thus achieving true three-dimensional knitted fabrics.This article designs a three-dimensional warp-knitted structure with vertical threading,simulates the designed structure using computer simulation,and achieves a clear expression of this type of fabric structure.The double-faced circular knitting machine is improved to design the weaving process of multi-layer warp-knitted fabrics with vertical threading,and to realize the on-machine weaving and testing of this type of fabric.Using the finite element analysis method,the mechanical properties of this type of fabric are analyzed and studied.NURBS curve simulation of center path and circular simulation of yarn cross-section using 3ds Max software is used to achieve three-dimensional simulation of multi-layer warp-knitted structures with unit loops,commonly used knitted fabrics,and vertical weaving threading.The simulation results can effectively display the spatial threading relationship and three-dimensional morphology of the vertical weaving threading structure.This provides a basis for understanding fabric structures.From the three-dimensional simulation results,it can be seen that this fabric structure has good anti-pilling and anti-snagging properties.The study focuses on the five-layer knitted fabric,and aims to produce the five-layer knitted fabric through improving the circular system of the double-faced knitting machine,designing weaving technology,and weaving the five-layer knitted fabric.The correlation performance of the five-layer knitted fabric and the double-faced spacer fabric was tested,and the results showed that the five-layer knitted fabric has superior anti-snagging,anti-pilling,warmth,breathability,and tensile strength performance compared to the double-faced spacer fabric.The warp-knitted fabric with orthogonal loops can be designed with various layers of fabric by adjusting the number of orthogonal warp threads according to the requirements.Additionally,it has a grip with orthogonal looped coils,making it a true three-dimensional knitted fabric.The mechanical properties of the five-layer knitted fabric are studied in this research.Starting from the single-cell loop structure,the geometric parameters of each loop are calculated,and the center line of the loop is constructed.Rhino software is used to establish a three-dimensional model of the vertical weaving three-thread twisting structure,transforming the theoretical calculation problem into a software application problem.ABAQUS finite element software is used to establish a tensile model of the single-cell loop and the vertical weaving five-layer knitted fabric,respectively,to simulate the longitudinal and transverse tensile test processes of the single-cell loop and the vertical weaving five-layer knitted fabric,and to analyze the changes in stress and strain during the tensile process of the vertical weaving five-layer knitted fabric from both micro and macro perspectives.The tensile test of vertical weaving five-layer knitted fabric is analyzed to verify the validity of the simulation results.The error between the simulation value and the experimental value is within 8%,which can accurately predict the mechanical properties of the vertical weaving three-thread twisting fabric.