Korea-Australia Rheology Journal, Vol.14, No.2, 57-62, June, 2002
Sensitivity analysis of melt spinning process by frequency response
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The sensitivity of the final filament to the ongoing sinusoidal disturbances has been investigated in the viscoelastic spinning using frequency response method. Amplification ratios or gains of the spinline cross-sectional area at the take-up to any disturbances show resonant peaks along the frequency regime, where the frequencies at these points directly correspond to the imaginary parts of the successive leading eigenvalues from the linear stability analysis. As shown in Jung et al. (1999) and Lee et al. (2001), the sensitivity results on the effect of various process conditions such as spinline cooling and fluid viscoelasticity, obtained by dynamic transient simulation have been corroborated in this study. That is, increasing spinline cooling makes the system less sensitive to disturbances, thus stabilizes the spinning. Also, an increasing viscoelasticity for extension-thickening fluids decreases the sensitivity of the spinning, i.e., stabilizing the system, whereas it increases the sensitivity of the spinning of extension-thinning fluids. Furthermore, it has been found in the present study that the inertia force as one of secondary forces causes the system to be more stable or less sensitive to process disturbances.
Keywords:frequency response;sensitivity;spinning;PTT fluids;spinline cooling;fluid viscoelasticity;inertia
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