Analyzing roller drafting dynamics with stochastic perturbations: Simulation approach

Abstract

This research investigates the effects that perturbations in roller drafting operations have on fiber bundles in the draft zone. In particular, it examines the effect of perturbations on the thickness of the output bundle. To do so, a test signal was characterized by a stochastic signal with an autocorrelation function and was generated using the Random Phase Spectral (RPS) method. Each stochastic signal represented perturbations in the roller drafting. Then, the spatial and temporal distributions of the linear density of the fiber bundle in the drafting zone were simulated, using the mathematical model that described the bundle flow dynamics in the roller drafting process, and the irregularities of the output linear density were estimated. Results showed that changes in the bundle cohesion, input linear density, and draft ratio led to distinctive variations with some special pattern in the output bundle linear density, but changes in the draft process speed did not. For example, perturbations in the bundle cohesion generated a stochastically periodic component in the irregularities of the output linear density. In contrast, periodic attributes generated from perturbations in the input linear density subsided in the output bundle as the perturbation intensity increased. At the same time, the output bundle irregularity was strongly influenced by the perturbation strength of the input linear density. Variation in the draft ratio appeared similarly in the output thickness irregularities. However, variations in the process speed did not influence the output irregularities, indicating that inertial effects of the fiber bundle on the draft dynamics can be neglected.