Effects of Bending Stiffness in Magnetic Tape

The elasticity of magnetic tape is an important factor in determining the shape of a tape loaded over a magnetic head. Over a single apex the radius of curvature of the tape is inversely proportional to the wrap angle and to the square root of the ratio of tape tension to bending stiffness. If a constant-pressure support is assumed instead of a knife edge, the radius of curvature increases considerably. A chart is provided for use in calculating the radius of curvature under different loading conditions. Over a double apex the results are the same as for a single apex except when the distance between apexes becomes small. By increasing the radius of curvature of the head to conform to the radius of curvature of the tape, the rate of head wear can be greatly reduced.