Correlations between creep, shrinkage, and dynamic mechanical characteristics of magnetic tape materials

Weick, Brian L.

doi:10.1002/app.33032

Cited by 11 publications

(34 citation statements)

References 91 publications

(181 reference statements)

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“…A model with a larger number of parameters is capable of capturing the characteristic roll-off behavior observed for PEN-based tapes and substrates, which could be attributed to relaxation characteristics of the polymer and/or shrinkage. 3,4 Figure 17, showing the radial stress in the wound roll as a function of nondimensional radial position for a seven-parameter model of LTO3, illustrates the effect of the increased stress described by the sevenparameter model at long time ranges. The stress fields in the wound roll are also predicted to increase in stress at long times.…”

Section: Viscoelastic Wound Roll Results For Three- Five- and Sevenmentioning

confidence: 98%

“…Other types of relaxation could be occurring in Tape C, which could be attributed to the coating process. 4 For the LTO3 tape shown in Figure 4, with parameters listed in Table I, there is a similarity between the three-and five-parameter Kelvin-Voigt models when compliance, retardation time, and viscosity parameters are compared. However, the sevenparameter model is a better fit for the data during the 10-100 h time period for the LTO3 tape.…”

Section: Experimental Testing Of Polymer Tapementioning

confidence: 88%

“…Newer proprietary tapes that use PET substrates with metalized layers applied to each side of the substrate to control dimensional stability have also been used in recent studies. 4 The specific viscoelastic characteristic measured for tapes in the experimental studies is called creep compliance, which has typically been measured at elevated temperatures (30, 50, and 70 C). Current studies have also enabled measurements to be performed at low and high relative humidity levels (15% and 75% nominal RH).…”

Section: Introductionmentioning

confidence: 99%

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Viscoelastic behavior of polymer tape in a wound roll

Acton¹,

Weick²

2011

J of Applied Polymer Sci

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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.

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Section: Viscoelastic Wound Roll Results For Three- Five- and Sevenmentioning

confidence: 98%

Section: Experimental Testing Of Polymer Tapementioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

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Viscoelastic behavior of polymer tape in a wound roll

Acton¹,

Weick²

2011

J of Applied Polymer Sci

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“…Rummel and Weick describe the need for ULDMA due to transitions observed in magnetic tape materials at near‐room temperature conditions. Weick also observed these transitions in earlier work using commercial DMA equipment, and noted that such transitions could lead to problems with archival storage of magnetic tapes due to changes in stress‐strain characteristics as the tape is stored in a roll. The investigation was therefore carried‐out using temperatures in the 25–70°C range, and frequencies of 0.006–0.065 Hz within this temperature range.…”

Section: Introductionmentioning

confidence: 85%

Dynamic mechanical analysis of barium ferrite magnetic tapes with aramid and poly(ethylene naphthalate) substrates

Berry

Weick

2014

J of Applied Polymer Sci

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Frequency‐ and temperature‐dependent viscoelastic characteristics of advanced materials used for high‐capacity digital magnetic tapes were analyzed using a custom ultra‐low frequency dynamic mechanical analyzer (ULDMA). The magnetic tapes studied both use barium ferrite (BaFe) magnetic particles. One tape uses an aromatic poly(amide) or aramid substrate, and the other tape uses a poly(ethylene naphthalate) or PEN substrate. ULDMA studies were performed for both types of tape materials using samples cut from reels and the substrates after the front and back coats were removed. Two‐hour experiments were performed at 25, 30, 50, and 70°C temperatures, and four test frequencies were used at each temperature: 0.006, 0.010, 0.033, and 0.065 Hz. Properties determined were the peak strain‐based elastic modulus, E, and the storage modulus, E′, loss modulus, E″, loss tangent, tan(δ), complex modulus, E*, and complex loss, E″/E*, expressed as a percentage. When compared with the PEN tape and substrate materials, the peak elastic modulus, storage modulus, and complex modulus were higher for the aramid materials. Substrates for each material exhibited higher elastic, storage, and complex moduli compared with their respective tapes. Through the complex loss percentage, comparisons were made between the aramid and PEN materials related to their viscoelastic characteristics. Finally, the influence of frequency was shown to have increasing relevance at higher temperatures, with the PEN tape and substrate exhibiting an increase in complex loss modulus in the 50°C range because of the β* secondary transition. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41478.

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“…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. In the previous work, the parameters that describe the tape material (namely, the creep compliance and viscosity parameters) are used to describe the behavior of the roll in the radial direction.…”

Section: Introductionmentioning

confidence: 99%

Orthotropic Viscoelastic Behavior of Polymer Tape in a Wound Roll

Acton

Weick

2013

Mechanics of Advanced Materials and Structures

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A model is developed to predict time dependent behavior of polymer tape in a wound roll where the bulk radial modulus, or intrinsic stiffness of the roll in the radial direction, has different time dependent properties than the tape material itself. This work examines the combined effects of viscoelasticity and the evolution of anisotropy and will aid in the development of technology to increase dimensional stability, ensuring that data may be read after long periods of time. The results of this work show that the evolution of anisotropy may amplify or counteract the effects of viscoelasticity in a roll.

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Correlations between creep, shrinkage, and dynamic mechanical characteristics of magnetic tape materials

Cited by 11 publications

References 91 publications

Viscoelastic behavior of polymer tape in a wound roll

Viscoelastic behavior of polymer tape in a wound roll

Dynamic mechanical analysis of barium ferrite magnetic tapes with aramid and poly(ethylene naphthalate) substrates

Orthotropic Viscoelastic Behavior of Polymer Tape in a Wound Roll

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