Simulation And Analysis Of Three-point Bending Property Of Woven Fabrics By Finite Element Method

Bending property of fabrics is the ability to resist bending deformation, it's closely related to the fabrics stiff resistance, wrinkle resistance, shape retention, softness and drape characteristics. It also directly affect the fabric formability and fabric applications. Therefore, it's necessary to study the method which can accurate, rapid, objective evaluate fabric bending properties.Woven fabric three-point beam bending is non-linear large deformation, and finite element method(FEM) is an effective way to solve the problem of non-linear deformation. Therefore, this paper used finite element simulation software ABAQUS to build five kinds of woven fabric models, and to simulate and analyze fabric three-point beam bending test, then the extraction of bending force- displacement curves were compared with the experimental curve. Stress distribution of the fabric and the press needle in bending process are obtained by FEM calculating, and we analyze the factors that affect the fabric bending properties. The results are as follows:(1) The finite element simulation parameters are set as follows: supporting needle diameter is 4mm, supporting needles spacing distance is 6mm, chuck distance is 100 mm, length of fabric is 180 mm, the curves of finite element simulation and experimental results are relatively close from trend and value. Among the characteristic values extracted from curve, the maximum flexural strength value of simulation is greater than the experiment, and the relative error is less than 10 percent. Left slope and right slope simulation and experiment relative errors of three kinds of fabrics are less than 10%, simulation and experimental bending work relative errors of four kinds of fabric are less than 10%, all fabrics width simulation values are close to the experimental value, their relative error less than 10%. So, the FEM simulation is valid as a method to study fabric bending properties.(2) According to the FEM analysis results, the fabric stress distribution can be obtained during bending process: Overall, warp yarn has larger force, weft yarn has a smaller force. The stress of yarn in contact with press needle is larger than the other part of the yarn. The yarn force distribution is as follows: warp yarn stress at press needle are maximum, on both sides of the maximum peak stress distribution is substantially the same. In the center of press needle, the stress distribution on the yarn spreads to both sides; the yarn stress distribution at supporting needle are relatively uniform, maximum stress distributes the yarn part which contact with supporting needle. Maximum stress of weft distribute the interwoven point at the head end of the yarn, the stress distribution of the other positions is relatively uniform. Stress distribution on the needle situations are as follows: stress distributes entire needle, and the whole needle has force, the stress on the press needle part which contact with the fabric is greater than no contact part, during the bending process, stress propagate along the radial of the needle. Since interaction force is changed between the needle and the fabric, so the stress changes along the longitudinal direction of the press needle.(3) Analysis of the fabric three-point beam bending factors are as follows: ?supporting needle diameters changes from 2mm to 6mm, the maximum bending force increases from 9.16 cN to 9.93 cN, left slope increases from 1.15cN·mm-1 to 1.31cN·mm-1, the bending work from 134.27cN·mm to 136.41cN·mm, width, right slope and bending work substantially increased. ?When supporting needles pacing distance increase from 6mm to 10 mm, simulation curve has same trend, the curve rises at first then falls, the biggest bending force, bending work and width are reduced, the increase of slope is not obvious. ?When the fabric ends have clamping force, there is a slight increase in curve peak value, the width of the curve is narrowed, the left slope of the curve increases and right slope has little change, fluctuation near the peak is large, but when there isn't clamping force, the curve relatively smooth when nearby peaks. ?When there isn't clamping force, with the chucks distance decreases, the curve peak value, the slope of curve, the bending work increase, but when the chucks distance is reduced to a certain extent, the ends of the fabric are always out the chucks, and the force between chucks and the fabric does not change, so curve does not change. ?When fabric length increases from 140 mm to 180 mm, maximum bending force, bending work and the width of simulation curve increase, while curve slope changes little.? Yarn modulus increases from 300 MPa to 500 MPa, the maximum bending force, left and right slope, bending work and width increase. ?When friction coefficient increases from 0 to 0.4, the maximum bending force, bending work, width increased significantly, the left and right slope increase slowly.?According to the simulation results, yarn poisons ratio increases from 0.1 to 0.3, the maximum bending force, bending work, width, and left and right slope change little, when the Poisson ratio, increases from 0.3 to 0.4, each characteristic indexes significantly increase. ?Influences of different fabric structure phase on simulation curves are as follows: the maximum bending force, left and right slope vale as: weft support face fabric> Warp support face fabric> equal support face fabric, bending work and width: Warp support face fabric> equal support face fabric >weft support face fabric. Weft support face fabric curve is steep and the peak width is quite narrow, curve fluctuation is relatively large. Warp support face fabric curve is less fluctuant, a equal support face fabric is smooth ? Different end and weft spacing fabrics have same curve shape. As end spacing increases, the maximum bending force, left slope, right slope, bending work and width increase, but increae marginally.