Finite Element Simulated Analysis On Tensile Mechanical Properties Of Weave Fabric

With the improvement of social economy and living conditions,people begin to pay more attention to performance of garment,not just appearance.The mechanical properties of the fabric directly affect the fabric's suitability,which is important accept of fabric quality evaluation.However,fabric tensile property is the most basic and common.At present,when fabrics are designed and tensile strength is analyzed,it is usually decided according to similar fabric by designers.The tensile strength is obtained by a series of processes including spinning,weaving and time-consuming tests.The processes are not only long and complicated,but also waste raw materials,especially for expensive raw materials.So in this paper,the tensile strength of weave fabrics is simulated by finite element method,and is predicted and optimized by the tensile strength of yarns.In this way,weave fabrics are not broken,research period is greatly shortened,and production cost is reduced.Moreover,it provides theoretical basis for further studying mechanical properties of the fabric.First,in this paper,the method of building weave model is introduced.Yarn is regarded as the smallest unit by controlling elliptical cross section and center line.The center line's equation is built by multinomial fitting method.Then the weave model is built with calculating fabric structure parameters.Second,using the unit-cell model of the cotton fabric,the periodic boundary conditions of the fabric unit cells are established so that the unit-cell model replaces the entire fabric model.The tensile process is simulated according to different fabric weaves,yarn line density,and the fabric density,and corresponding experiment verification is presented to explore the tensile properties of the fabric.Finally,the fabric model is expanded as same as tensile test specimen size.Tensile tests and numerical simulations of the fabrics of different fiber raw materials are performed,and longitudinal stress-strain curves,horizontal changed rate curves are established,analyzed and compared to study the dynamic changes of fabrics.Results show that:(1)the error of tensile properties of unit-cell cotton fabric between the simulated and the experimental results is about 5%.Under other conditions are the same,when fabrics are stretched along the warp direction:(1)warp average stress,warp average strain of plain weave are larger than twill weave's,and twill weave's is larger than satin weave's.Warp elasticity modulus of plain weave is less than twill weave's,and twill weave's is less than satin weave's.And weft average strain of twill weave is larger than plain weave's,plain weave's is larger than satin weave's.(2)The larger the yarn density,the larger the warp average stress,the warp average strain and the elasticity modulus,and the fewer the average weft strain.(3)With the increase of warp and weft density,the warp average stress,the warp average strain,the weft average strain and the elasticity modulus all increased to some extent.(2)For six kinds of weaves' stress-strain curves,the trend of numerical simulated curve and experimental curve are basically the same.The tensile curves of different materials' fabrics are obviously different.Polyester fabric's curve is taken for example.Polyester fabric tensile process is divided into four stages: the first stage is elastic deformation with great initial modulus;the second stage is yield deformation with slowly changing stress;the break different timeliness of polyester filaments caused stress fluctuations during in stage3,until completely broken in fourth stage.(3)The change stages of horizontal changed rate curve just coincide with the changed stages of the tensile curve.Before the fabric break point,the horizontal changed rate curves is mainly divided into three stages: the first two stages are the mechanical high modulus area,the mechanical low modulus area,or the mechanical enhancement effect;in the last stage,the rate of lateral shrinkage change is usually reduced and tends to be stable,and the fabric width does not change much.