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A Eulerian approach is applied to the finite element modelling of neo-Hookean rubber material. Two major problems are encountered. The first problem is the construction of a n algorithm to calculate stresses in the rubber material from velocities instead of displacements. This problem is solved with a n algorithm based on the definition of the velocity gradient. The second problem is the convection of stresses through the finite element mesh. This problem is solved by adapting the so-called Taylor-Galerkin technique. Solutions for both problems are implemented in a finite element program and their validity is shown by test problems. Results of these iinplementations are compared with results obtained by a standard Lagrangian approach finite element package and good agreement has been found. 1. 3. 4. 5. 6. 7. General Introduction O, General IntroductionMagnetic tapes and discs are very important data storage media; Magnetic recording is used for a broad range of applications, such as thc storage of music, TV-images, pictures and coniputcr dala. Thc main advantagcs of magnetic media are the high density of information, which can be stored on tape or disc, their low costs, and their excellent reusability properties.Philips has been, and still is, spending much effort on the research on magnetic recording. Video recording is one of the most important research topics on magnetic recording. In this general introduction, the basic principles behind video recording are -2-A schematic layout of a regular VHS video recorder is depicted in figure i. As can be seen in this picture, the tape path in a videorecorder is much more complicated than the path in an audio cassette recorder. The tape is taken out of the cassette and guided by pens and rollers along several units. The guidance dimensional tape path. The main unit in the tape path is the scanner. This is a complex high precision rotating drum, containing the magnetic heads, which read and write the video signal on the tape. In general, the tape is driven by two reel motors, above which the tape cassette is positioned, and by the so-called capstan drive. An enlarged picture of this capstan drive is presented in figure 2. e!en?ents lift thc t29e i W t Gf its cassette p!une, which resu!ts I t , 2 true three TAPE RIGID CYLINDER Fig.2. Capstan DriveThe capstan drive consists o f a rigid metal shaft (capstan), driven by a DC-motor, and a pinch roiler, which is pressed against the capstan by an elastic spring. This pinch roller is a rigid metal cylinder, covered by a rubber coating.In the metal cylinder one or two roller bearings or sliding bearings are installed. The tape is placed in the nip between capstan and pinch roller. Due to frictional forces in the contact areas, the tape is transported Important trends in modern video recording are, amongst others, a strong increase of the information density on tapes and the introduction of new features. A higher density of information is obtained by the application of smaller track widths on the tape and by a reducti...