Viscoelastic behavior of polymer tape in a wound roll

Abstract

in Wiley Online Library (wileyonlinelibrary.com).ABSTRACT: A viscoelastic computational model is developed that uses experimentally determined viscoelastic material properties as input and can be used to predict the behavior of a tape material in a wound roll as stresses relax over time. Experimental creep test results are used to find best-fit creep-compliance parameters to describe two high density data storage tape media. The two tapes used in the analysis are a developmental tape with a poly(ethylenenaphthalate) (PEN) substrate and metal particle (MP) front coat similar to linear tape open (LTO4) (referred to in this work as ''Tape C''), and LTO3, a commercially available tape with a PEN substrate and MP front coat. Sets of best-fit creep-compliance parameters are determined for both tapes. The differences between the predicted behavior using three-, five-, and sevenparameter Kelvin-Voigt models are evaluated, both for a benchmark case and in a viscoelastic wound roll model.The choice of material model is found to significantly influence the predictions of the wound roll model. The differences between different material models for the same material are on the order of the differences found between the two different materials. A material model with a higher number of creep-compliance parameters, although more computationally expensive, produces better results, particularly over long spans of time. The relative differences between the three-, five-, and seven-parameter models are shown to be qualitatively consistent for several variations in the computational model setup, allowing predictions to be made based on simple benchmarks.

Orthotropic Viscoelastic Behavior of Polymer Tape in a Wound Roll

“…investigates the viscoelastic behavior of an orthotropic tape material using numerical methods, and is an extension of a previously developed isotropic viscoelastic model [2]. Previous studies have shown that creep compliance data obtained using LTO3 and developmental tape products [7] can be used as input to an isotropic viscoelastic model which can predict the evolution of the wound-in tape stresses over time.…”

“…Figure (a) shows a schematic of the geometry of the wound roll. In (b), the radial and tangential stresses are shown on a single layer of tape [2].…”

“…The physical representation of the Kelvin Voigt viscoelastic material model. Where the 7-parameter model is used, D i and i for i = 1, 2, 3 are determined by experimentation and curvefitting [2]. about the coupling of viscoelastic behavior with anisotropic behavior, which is the goal of the current work.…”

“…It is necessary to quantify the expected viscoelastic behavior of tape in order to predict the dimensional stability of tape after a period of time has elapsed, and to ensure that data contained on the tape is readable over the expected lifetime of the tape [1]. The tape under consideration is LTO3, and the results follow upon the development of a viscoelastic model, which treats the tape roll as isotropic [2].…”

Identification of the viscoelastic parameters of a polymer model by the aid of a MCMC method

“…These parameters can be estimated by several techniques that utilize the response of the material to a properly selected external excitation. It is commonplace that estimates for the parameters are 1 found by a least squares fit to measurement data, see, for example, (Vuoristo et al, 2000;Sorvari and Malinen, 2007;Weick, 2009;Acton and Weick, 2011). A particular feature of mechanical analog models for viscoelastic materials, consisting of arrangements of springs and dashpots, is that the number of material parameters, that is, the number of springs and dashpots, is not fixed beforehands.…”