Location

Seattle, WA

Start Date

1-1-1996 12:00 AM

Description

High recording density with the home-use digital VCRs requires the use of narrow tracks, short recording wavelength, and thin magnetic tapes. Knowledge of Young’s modulus of the tape is essential for the precise positioning of the tape on the rotating drums and then a stable tape-to-head interface. The magnetic tapes usually show different Young’s moduli for the machine direction (MD) and the transverse direction (TD) [1]. The anisotropy develops mainly in the base film of polyethylene terephthalate (PET) through the partial crystallization and the crystallite orientation alignment during the stretching process on the tapes [2], while the original PET sheet, from which the tapes are cut, shows much less anisotropy. This situation requires the determination of Young’s moduli for both MD and TD of the tape. The tapes on play are straightened by tensile loads, which should be controlled with Young’s modulus for the MD. Too much load may distort the recorded tracks or damage the tape. Besides, the vertical load is applied onto both edges of the running tape by the guiding rollers. Again, too much load may induce the tape buckling. Critical load is proportional to the Young’s modulus in the TD. Large moduli are desirable for both directions.

Volume

15A

Chapter

Chapter 1: Standard Techniques

Section

UT Guided Wave Propagation

Pages

239-246

DOI

10.1007/978-1-4613-0383-1_30

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

Leaky Lamb Wave Along VCR Magnetic Tapes

Seattle, WA

High recording density with the home-use digital VCRs requires the use of narrow tracks, short recording wavelength, and thin magnetic tapes. Knowledge of Young’s modulus of the tape is essential for the precise positioning of the tape on the rotating drums and then a stable tape-to-head interface. The magnetic tapes usually show different Young’s moduli for the machine direction (MD) and the transverse direction (TD) [1]. The anisotropy develops mainly in the base film of polyethylene terephthalate (PET) through the partial crystallization and the crystallite orientation alignment during the stretching process on the tapes [2], while the original PET sheet, from which the tapes are cut, shows much less anisotropy. This situation requires the determination of Young’s moduli for both MD and TD of the tape. The tapes on play are straightened by tensile loads, which should be controlled with Young’s modulus for the MD. Too much load may distort the recorded tracks or damage the tape. Besides, the vertical load is applied onto both edges of the running tape by the guiding rollers. Again, too much load may induce the tape buckling. Critical load is proportional to the Young’s modulus in the TD. Large moduli are desirable for both directions.