A filament bundle is a kind of filament assembly with less twist or nontwist. It is a viscoelastic body and has a large aspect ratio. Its large deformation during motion over a wide range is a universal phenomenon in many textile processes. The dynamic viscoelasticity of the filament bundle, gravity, and air resistance are three important factors affecting the filament bundle's dynamic behavior. Taking account of these factors, a filament bundle dynamics analysis method is proposed in a series of three papers. This paper, the first in the series, presents an approach to model the dynamics of the flexible filament bundle with viscoelasticity and to analyze its dynamic behavior under the action of gravity and air resistance. The filament bundle element (FBE) is established based on absolute nodal coordinate formulation (ANCF), in which slope vectors and global coordinates are applied. The approach presented in this paper is well suited for the analysis of large deformation motions of filament bundles. As an example, a dynamic model was established to predict the filament bundle's trace during its swinging through large displacements under the action of gravity and air resistance, taking into account the filament bundle viscosity. The nonlinear differential equations of the filament bundle system were solved using MATLAB. Furthermore, the swing traces of the filament bundle in a closed Plexiglas box with different vacuum degrees were recorded using a high-speed camera to prove the validity of the established filament bundle model based on ANCF.
This paper continues the previous study and presents a dynamic modeling approach for a high-speed winding system. To meet the requirements of high-speed winding, a twin-rotor coupling structure is adopted in the winding system. It is a complex spindle system, due to its high speed, heavy load, frequency-dependent coupling parameters, and time-varying rotational speed. In this paper, an approach to establishing a finite element model of the winding system is proposed to predict its dynamic behavior characteristics during the winding process. First, the spindle and contact roller models of the discrete single component are developed based on Timoshenko beam theory. Bending, transverse shear effects, and gyroscopic moment are considered in the models. The contact stiffness between the contact roller and the packages to be wound on the spindle is simplified by a nonlinear spring. The contact stiffness is identified by dynamics analysis in ANSYS® 17.0. Next, a fully dynamic model of the winding system, which consists of the spindle subsystem, the contact roller, and the flexible coupling elements, is established. Third, the Newmark method is used to develop the program to solve the dynamic equations in MATLAB® 2013b. Finally, the effects of the supporting system and contact state on the winding system's dynamic response are investigated. The results indicate the model of the winding system presented in this paper is suitable for predicting dynamic performance during the winding process.
High-speed ring spinning is limited by issues such as yarn quality and yarn breakage, and the spinning tension significantly affects yarn breakage and winding speed. The shape of the balloon in ring spinning is closely related to the distribution of tension within the yarn. In this study, a force analysis of the balloon yarn was conducted focusing on the balloon section during ring spinning, and a mathematical model of the balloon was established. The model included factors such as the centrifugal force, Coriolis force, and the air resistance of the yarn. Suitable parameters were then selected to extract the balloon trajectory curve and compare it with simulations to validate the model. The model was used to analyze the effects of balloon speed, yarn linear density, balloon bottom radius, balloon height, and yarn tension at the top of the balloon on the yarn tension at the bottom of the balloon, and the overall shape of the balloon. The balloon model established in this study could also be used for the study of balloon yarn tension in other processes. The effects of the main parameters influencing the yarn tension of the multi-balloon can provide a theoretical reference for enhancing the design of high-speed ring spinning.
In the process of producing covered yarn, a single outer wrapping yarn forms a balloon when it rotates at high speed. In this work, we used a mathematical model of a balloon formed by polyamide,which is a common outer wrapping yarn, and verified its feasibility with a group of experimental data. The effects of yarn tension, rotation speed, balloon height and turntable radius on the balloon shape were analysed and the correctness simultaneously demonstrated.
This paper proposes a new covered yarn system in which the tension of spandex elastic yarn drawing is controlled. By analysing the relationship between the draw ratio and yarn tension, it was verified that the new tension controlled drawing system is feasible and results in yarns of superior quality and process stability.
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