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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The response of quasi-brittle materials is greatly influenced by their microstructural architecture and variations. To model such statistical variability, Statistical Volume Elements (SVEs) are used to derive a scalar fracture strength for domains populated with microcracks. By employing the moving window approach the probability density function and covariance function of the scalar fracture strength field are obtained. The Karhunen-Loève method is used to generate realizations of fracture strength that are consistent with the SVE-derived statistics. The effect of homogenization scheme, through the size of SVE, on fracture pattern is studied by using an asynchronous spacetime discontinuous Galerkin (aSDG) finite element method, where cracks are exactly tracked by the method’s adaptive operations.