Research On Vibration Characteristic Of Viscoelastic Warp Of High Speed Loom

With the speed of weaving of textile machinery greatly improved, requirements of weavingefficiency and the quality of fabric were constantly improving in the process of the weaving ofhigh speed loom. The vibration of warp could trigger mutual frication of warp and elongation ofwarp, even have an important influence on the wrap tension deform and cloth-mobile. If thevibration of warp couldn’t be effectively controlled, it would cause yarn breakage of warp, evenaffect weaving efficiency of fabric. In particular,this effect was even more obvious at high speed.Therefore, this paper adopted nonlinear vibration method to analyze the vibration of warp andwas to provide a theoretical basis for effective control of the warp vibration.Firstly, the vibration model of warp was established by the method that elongation of warpwas converted to tension variations of warp of fixed ends during the movement. At the same time,outside damping (air resistance, friction etc), material properties of warp and geometry nonlineardeformation were considered. Stress-strain relations were obtained by analyzing geometrydeformation of the micro-segment model of the warp. The fluctuation process of warp yarn wasanalyzed by the nonlinear vibration method and elastic mechanics. A differential equation of thewarp yarn vibration in lengthwise and crosswise was established by Newton law.Secondly, the fluctuation process of warp was analyzed by nonlinear vibration. The partialdifferential equations were converted into ordinary differential equations by the way ofsecond-order Galerkin truncation. The vibration was simulated by using Matlb and the4-orderRunge-Kutta. And this paper discussed response of transverse and longitudinal vibration of warp,effects of longitudinal vibration on the lateral vibration of warp and the impact of materialproperties and various parameters of yarns on the response of transverse vibration. And measuresto prevent yarn breakage of warp and methods to reduce excessive elongation of warp wereproposed. It has been analyzed that the influence of tension fluctuation ratio to the bifurcationand chaos, the range of tension fluctuation ratio of warp in the area of periodic motion was got.Finally, in order to study the stretching vibration of warp yarns, this paper adopts nonlinearvibration method and elastic mechanics to analyze the movement of warp yarns. Kelvin model is selected as Warp viscoelastic constitutive relations. Mathematical equations of the stretchingvibration of warp yarns is established. And using Galerkin truncation method to separate thevariables of time and space and to discrete partial differential equations into ordinary differentialequations. Natural frequency is solved. the effect of various parameters on the stretchingvibration of warp yarns is investigated by4-order Runge-Kutta method and matlab, and to verifythe correctness of the calculation formula of the natural frequency. According to suffer the effectsof conditions of external excitation, a formula is introduced for critical velocity of warp yarns forprevention of sympathetic vibration when loom starts. According to suffer conditions of externalexcitation, when external incentives were in the form of one or two superimposed harmonicforce, the vibration response of forced vibration of warp was analyzed, and some laws aboutforced vibration of axial movement of warp. When the beating, changes of warp tension underthe impact were analyzed. The theoretical basis was provided for actual production.