Analysis On Heat Transfer Properties Of Fabric Based On ABAQUS

With the improvement of living standards,people's requirements for clothing are not limited to wear-resistant,but more attention is paid to the comfort and environmental protection of clothing.The heat transfer performance of fabric is an important index for evaluating its comfort.Changes in fabric-related parameters will affect the heat transfer and its heat transfer performance.The traditional inquiry method mainly adopts the experimental inquiry method,that is,people optimize through change different parameters and a large number of experiments to determine whether the product meets the expected settings.This process is a long cycle and complicate and uncertainty.In recent years,using the finite element method to analyze fabric properties has become a research hotspot in the field of textile science.Based on the finite element method,this paper proposes a theoretical method that can predict and analyze the heat transfer performance of fabrics effectively.This method can omit the complexity Process,analysis problems rely on material characteristics and physical models,achieve the purpose of save resources,reduce production costs,and shorten the inquiry cycle.Firstly,the geometric parameters and characteristic points of the fabric are obtained by microscopic observation method in this paper,and the physical model of the fabric is established by fit the yarn center-line equation based on the interpolation formula.The effective thermal conductivity of the yarn is calculated from the anisotropy of the thermal properties of the fiber and the air content in the yarn,and the material orientation is determined.Then,the heat transfer environment of the fabric was created in ABAQUS finite element software,the heat transfer performance of the fabric was analyzed,and the validity and feasibility of the modeling method and numerical simulation results were verified by the fabric insulation test and the fabric surface temperature test.Finally,based on the above verification,different models were established and the influences of fabric structure,fabric compactness,fabric thickness and air layer thickness on the heat transfer performance of the fabric were explored.Meanwhile,a model was established to analyze the heat transfer performance of the multi-layer fabric and then the influence of the number of layers on the heat transfer performance of the fabric was analyzed.Results show that:(1)the method of interpolation formula fitting yarn center-line can establish a more accurate model,considering the material anisotropy and the yarn effective thermal conductivity can reduce the error.The difference rate between theoretical value and experimental value of finite element model is less than 9%.The validity of the numerical results of the heat transfer model in simulating the heat transfer performance of the fabric and the feasibility of analyzing the heat transfer process of the fabric based on the finite element method are proved.(2)After analyzing the influence of fabric structure,fabric tightness,fabric thickness and air layer thickness on heat transfer performance,It can be found that the change of different fabric parameters will change the length of heat transfer channel and the air content between the yarns,and then have certain influence on its heat transfer performance.The number of interlacing and the floating line have an effect on its heat transfer.The more interlacing of warp and weft yarns,the shorter the floating line,the less air bound between the yarns,and the better heat transfer performance.In the range of fabric tightness of 72-83%,the thermal conductivity of the fabric increases with the increasing of fabric tightness.With the increase of yarn density,the thickness of the fabric increases gradually,the heat transfer channel in the direction of thickness becomes longer,and the heat transfer performance decreases.With the increase of thermal conductivity of fiber material,the thermal resistance of the fabric decreases.With the gradual increase of the air layer thickness between the fabric and human skin,the temperature of the outer surface of the fabric gradually decreases,and the gradient of temperature drop is smaller and smaller.(3)After analyzing the heat transfer performance of the multi-layer fabric,it can be found that the heat transfer efficiency of the fabric is reduced due to the air layer generated by the structure and the increase of the fabric thickness,and the thermal resistance value of the fabric is greater than the sum of the thermal resistance values of the single-layer fabric.For the multi-layer superposed fabric,with the increase of the number of layers,the thermal resistance of the fabric increases gradually,the time to reach the thermal balance is longer and longer,the lower the surface temperature,the less heat is transferred.