ATTENUATION OF STRESS WAVE PROPAGATION IN PERIODICALLY LAYERED ELASTIC MEDIA

An exact viscoelastic analogous relation between a periodically layered elastic medium and a homogeneous viscoelastic medium was introduced, based upon which a short-time relaxation function was developed. Both the wave front decay and the spatial attenuation of stress waves in a periodically layered medium were studied. It was shown that the spatial attenuation of long waves propagating in a periodically layered elastic medium describes the attenuation of the wave trailing the wave front, while the spatial attenuation of a short wave characterizes the wave front decay. The effects of thickness ratio of the two constituent layers, their mechanical properties, and the cell thickness on the attenuation of stress wave propagation were examined. The results showed that the use of the short-time analogous relaxation function is valid for the attenuation analysis of stress waves propagating in a periodically layered elastic medium.