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Transient wave propagation in a viscoelastic layered composite—An approximate theory

Birlik, Gülin A.
Mengi, Yalçın
The approximate theory proposed in reference [1] for viscoelastic layered composites is appraised by applying it to a transient wave propagation problem. The problem involves a viscoelastic slab subjected at one end to a dynamic pressure which has either step or trapezoidal variation in time while its other end is kept fixed. The faces of the slab are parallel to the layering. For the case in which the composite material is elastic, which can be obtained from viscoelastic case when viscous terms vanish, the wave profiles for normal stress and particle velocity are determined by using exact and approximate theories, and they are compared. It is found that even the lowest order approximate theory is capable of predicting the essential dynamic characteristics of the layered composite correctly. Further, the influence of the viscosity on wave profiles is studied by using the approximate theory. For the time integration of the approximate equations a numerical algorithm based on FFT is employed.