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Full-Text Articles in Mechanical Engineering

Nanofatigue Studies Of Ultrathin Hard Carbon Overcoats Used In Magnetic Storage Devices, Xiaodong Li, Bharat Bhushan May 2002

Nanofatigue Studies Of Ultrathin Hard Carbon Overcoats Used In Magnetic Storage Devices, Xiaodong Li, Bharat Bhushan

Faculty Publications

A technique to perform nanofatigue experiments was developed. This technique utilizes a depth-sensing nanoindenter with harmonic force. The nanofatigue behavior of 20 nm thick amorphous carbon coatings was studied. The contact stiffness was monitored continuously throughout the test. The abrupt decrease in the contact stiffness indicates fatigue damage has occurred. The critical load amplitude, below which no fatigue damage occurs, was identified. It was found that the filtered cathodic arc coating exhibits longer fatigue life than a direct ion beam coating. Failure mechanisms of the coatings during fatigue are also discussed in conjunction with the hardness,elastic modulus, and fracture ...


Width-Wise Variation Of Magnetic Tape Pack Stresses, Jonathan A. Wickert, Y.M. Lee May 2002

Width-Wise Variation Of Magnetic Tape Pack Stresses, Jonathan A. Wickert, Y.M. Lee

Jonathan A. Wickert

A model is developed for predicting the stress and displacement fields within a magnetic tape pack, where those quantities are allowed to vary in both the pack's radial and transverse (cross-tape) directions. As has been the case in previous analyses based upon one-dimensional wound roll models, the present approach accounts for the anisotropic and nonlinear constitutive properties of the layered tape, and the incremental manner in which the pack is wound. Further, such widthwise variation effects as differential hub compliance and nonuniform winding tension, which can be significant in data cartridge design, are also treated in the model. The ...