Dynamic instability and measurement of characteristics of flexural waves in fine fibers

摘要

An experimental method of investigating the phe-nomenon of dynamic loss of stability is developed. In a fiber, the longitudinal unloading wave is initiated from the set state of static tension. Its speed is determined using the electromagnetic-radiation effect [1]. After the wave reflection from a fiber-fastening point in the form of a compression wave, the wave energy begins to con-vert into dynamicflexure energy. This process is recorded by a highspeed video camera. From the video records, we determine the lengths, amplitudes, flexural-wave velocities, Young’s modulus, and also the mass velocity of longitudinal motion from the position of the fiber’s free end. The classification of various scenarios of instability development depending on the unloading-wave intensity is proposed.