Relaxation of Internal Forces in a Wound Reel of Magnetic Tape

Abstract

Equations were developed to predict the relaxation of the internal stresses of a wound reel of magnetic tape, assuming a homogeneous and isotropic material which, under shear, exhibits instantaneous elasticity, delayed elasticity, and creep; and under hydrostatic stressing, shows elastic behavior. Numerical examples obtained with the aid of a high-speed digital computer indicated that the internal stresses introduced during the winding operation continue to relax. Given sufficient time in storage, the wound reel will approach stress-free conditions, thus exposing the tape to mechanical damage during transportation and reuse.