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Abstract
All thin materials, such as textiles, papers, polymers, or metals, are handled on rollers during manufacture and subsequent use. This requires several unwinding and winding processes. The goal of this study was to investigate the friction behavior of fabrics relative to sliding velocity and to introduce friction coefficient evolution in a fabric transport model. For the experimental part, a specific fabric/roll friction bench is presented. The friction coefficient was calculated from the capstan equation. The evolution of the friction coefficient was quantified relative to the sliding velocity for different textile fabrics and also for a polymer and a paper web. The influence of some measurement process parameters was studied: web tension, roll diameter, and wrap angle. The friction coefficient initially increased with sliding velocity and then became constant. This phenomenon can be explained by the deformation of the fabric due to friction, thereby inducing an increase in web tension with the sliding velocity. The relationship between tension and rolling friction behavior of the fabric was investigated. The variability of the friction coefficient was introduced to web/roll simulator, and improvements to the simulator are shown.
Keywords
friction, capstan, textile fabric, winding-unwinding, fraction cycle, traction cycle
(ProQuest: ... denotes formulae omitted.)
The goal of this study was to investigate the rolling friction behavior of textile fabrics and to insert some tribological features into a handling system model. It is useful to know the friction coefficient evolution in order to improve simulators used in web handling, particu- larly in unwinding-winding operations.1,2 These simu- lators are used for performance analysis, controller design, or optimization of the web handling process. The present study concerns the process between unwinding and winding.
The winding and unwinding phases have been mod- eled with consideration to nip load.3,4 However, the friction between textile fabrics and rollers has been rarely reported in the scientific literature. The listed publications concerns essentially fiber, filament, or yarn.
In web/roll friction, the friction coefficient is com- monly achieved using the capstan equation. This equa- tion, known since the 18th century (Bernoulli and Euler), is used to calculate the friction coefficient ^ between an inextensible rope and a roll.5 The rope is wrapped at an angle ^ to the roll surface (Figure 1). A mass is fixed at...