Research On Tribological Behavior Of Macro And Mesoscopic Glass Fiber Textiles

Textile composite materials are widely used in automobiles,ships,construction,pipes and containers due to their high specific strength and high specific modulus.Fibers,yarns or fabrics are used as reinforcement parts of composite materials,and their own qualities and properties determine the mechanical properties of the formed composite materials.However,friction,as a behavior throughout the whole life cycle of textile production,processing and service,affects and determines the quality and performance of multi-scale textiles.Studying the tribological behavior of multi-scale textile has important theoretical and practical significance for guiding the adjustment of process parameters and improving the quality of textiles,and ensuring the mechanical properties of composite materials.This thesis takes macro and mesoscopic glass fiber textiles as the object,and based on the self-designed and developed surface friction test experimental platform,studies the tribological behavior of glass fiber tow/tool,tow/tow,fabric/tool and fabric/ fabric.The main research contents and main conclusions of the thesis are as follows:(1)According to the structural features of glass fiber tow and fabric,the preparation method of tow and fabric is proposed.Based on the relevant standards of textile friction test,a test platform for the curved-surface friction test of the tow and the fabric is designed and built.For the interlayer friction test of fabrics,a special test roller is designed,and a test method for the curved-surface interlayer friction test of fabric is proposed.Visualization test methods for the cross-sectional shape of the tow and the contact shape between the fabric and the tool are designed.(2)A methodology by combining the finite element simulation,the mathematical model and experiment is used to reveal the mechanism of the friction behavior of towon-carrier.The results show that the nonlinear relationship between the contact area and the normal load is the reason that the friction force between the tow and the carrier increases nonlinearly with the normal load.Then,the influence of the test conditions on the friction coefficient between the tow and the curved-surface carrier is studied experimentally.Results show that the friction coefficient increases with the increase of tension and relative velocity;the tension and relative velocity act as a pair of "coupling factors" to affect the friction coefficient between the tow and the curved-surface carrier.Finally,the friction coefficient is fitted,and the results show that the proposed improved nonlinear friction model involving tension and relative velocity can well characterize the evolution of the friction coefficient between the tow and the carrier.(3)The lateral compression behavior between two tows is simulated by finite element simulation method.Combined with the Hertz contact theory and the adhesionshearing theory,it is pointed out that the contact area of inter-tow follows a nonlinear characteristic with the increasing normal load,resulting in a nonlinear relationship between the friction force and the normal load.Then,the influence of test conditions on the friction coefficient between tows is studied based on the curved-surface friction test rig.Results show that the friction coefficient of inter-tow has a positive correlation with the relative velocity and the tension on the upper tow.Finally,the proposed improved nonlinear model is used to fit the friction coefficient of inter-tow,and the results show that the model is also suitable for characterizing the evolution of the friction coefficient between tows with the tension and relative velocity.(4)Based on the visualization method,the evolution of the contact behavior between the fabric and the curved-surface carrier is tested.The results show that the contact between the fabric and the carrier is essentially the contact between the warp or weft yarns at interweaving points of warp and weft yarns and the carrier,and the contact area between the fabric and the carrier increases nonlinearly with the increasing normal load.Then,the influence of the test conditions on the friction coefficient between the fabric and the curved-surface carrier is studied experimentally.The results show that the coefficient of friction increases with the increase of tension;the influence of relative velocity on the coefficient of friction is affected by fabric structure and tension conditions.Finally,a compound friction model that takes into account the tension and relative velocity,and integrates the contact behavior of the warp and weft yarns is proposed to fit the friction coefficient.The results show that the model can well characterize the evolution of the friction coefficient between the fabric and the carrier.(5)The friction behavior and its mechanism of interlayer friction of the fabric is studied.The results show that the superposition state between the interweaving points of warp and weft yarns on the fabric surface of the upper and lower layers determine the interlayer friction coefficient.Thereby fluctuating the friction coefficient between the fabric layers periodically with the relative position of the layers,and the displacement corresponding to the fluctuation period is consistent with the geometric parameters of the fabric cyclic structure.In addition,the initial contact state between the layers along the friction direction determines the static friction coefficient between the fabric layers.Interlayer dislocation along the direction perpendicular to the friction direction introduces a second peak in a single period of the friction coefficient curve.The friction coefficient between fabric layers decreases with the increasing tension,but increases with the increasing relative velocity.The proposed compound friction model is used to fit the friction coefficient between fabric layers.The results show that the model is also suitable for characterizing the evolution of the friction coefficient with tension and relative velocity.In this thesis,the contact behavior and friction behavior between the macro and mesoscopic glass fiber textiles and the carrier and interlayer are studied by combining finite element simulation,mathematical modeling and experiment exploration.The mechanism of friction behavior of macro and mesoscopic glass fiber textiles is analyzed.The effect of tension and relative velocity on the friction coefficient of macro and mesoscopic glass fiber textiles is revealed,and mathematical models are proposed to characterize the evolution of the friction coefficient of macro and mesoscopic glass fiber textiles with tension and relative velocity.The relevant research results of this thesis are expected to enrich the multi-scale textile tribology theory,which is of great significance to predict the friction behavior of textiles,guide the quantitative adjustment of control parameters in the weaving process,realize the transformation and upgrading of intelligence the weaving equipment,and improve the weaving process and quality of textiles.