Study Of The Creep And Transverse Vibration Of The Loom Warp Based On Burgers Four-element Model

With the rapid development of modern science & technology, the weaving technology of loom is on its way of becoming more and more automatic, high-speed and intelligent. The tension changes of the loom warp have a significant effect to the weaving performance of the loom, which can be mainly described in two aspects. On one hand, it will lead to the occurrence of uneven density of fabric due to the change of weaving position after a shut down-restart process. This is because the fabric and loom warps are under great tension which will trigger them to move towards the cloth fell position during the shut-down stage of the loom. One the other hand, warp-break is very common during a weaving process, which will lower production efficiency. In this paper, the transverse vibration and vibration characteristics of the loom warps were studied, the results of which provided a theoretical support to the solutions of improving weaving efficiency of the loom.First of all, the constitutive relationship of the warp was analyzed, the elastic creep model was set up and creep tests on warps with different linear densities were studied. Nonlinear fitting on the experimental data was done in MATLAB. As a result, Burgers four-element model was determined as the optimal model to characterize the yarn creep properties and the parameter values of each element are obtained through calculation. With the corporation of the motor and the winding mechanism after a restarted action, the warps can be restored to the right position by reversing the axis.Secondly, the viscosity parameter of Burgers four-element model is converted to that for a Finite Element Analysis through Prony series. The results of the transient finite element dynamic analysis are consistent with the experimental results which indicates a nonlinear characteristics during the creep process.Finally, the forced movement of the warps during the weaving process was also studied with the applying of a viscoelastic warp vibration model. In this model, both the viscoelastic-forced movement and geometric distortion of the warp were being considered. Besides, the force and movement of a micro segment of warp was analyzed. This paper also performed a nonlinear dynamics analysis to the warp model and getting the nonlinear transverse vibration equations of viscoelastic warp. After that, the equations was truncated by first-order accuracy with Galerkin truncation method and the effect of the yarn properties and other parameters to the transverse vibration was studied by using 5-order Runge-Kutts-Felhberg. The results show that the vibration frequency and amplitude of the warp can be reduced by improving the speed of the warp, increase the damping coefficient and reduce the tension fluctuation ratio, thus obtain a decrease of warp-break rate.