“…In the recent years, many researchers showed interest in problems involving Kelvin-Voigt damping where different types of stability, depending on the smoothness of the damping coefficients, has been showed (see [7], [8], [25], [26], [28], [31], [34], [35], [39] and [41]). Moreover, there is a number of new results concerning systems with local Kelvin-Voigt damping and non-smooth coefficients at the interface (see [3], [5], [20], [21], [22], [27] and [37]).…”