Introduction

Early in my engineering consulting career, development work for tape drives used as backup storage devices of computer data was just beginning. I was assigned the responsibility for developing performance and operational standards. One problem associated with tape drives is that data reliability is sensitive to temperature extremes. As part of the work performed on improving data reliability it was of interest to estimate the time required for tape packs to return to room temperature (RT) after extended exposure to high temperatures, such as when a tape pack is left in an automobile all day or exposed to direct sunlight. In this investigation both conventional hand solutions and finite-element analysis (FEA) techniques were utilized to estimate midpack temperature response (function of time) as the tape material (polyester) cools to room temperature. Figure 12.1 shows a typical tape pack design concept. It was desired to estimate the time for the tape pack center to return to room temperature (72 F) after a temperature soak at 130 F.

Figure 12.1: Tape pack with aluminum hub.

The presence of the aluminum hub on which the tape is wound made hand solutions for the transient heat-transfer solution quite difficult to solve. Therefore, FEA techniques were decided to be the most viable technique. Before beginning development of the FEA idealization, I recommend doing sample warmup problems with known textbook solutions to a simplified version of the actual geometry shown in Fig. 12.1.