“…Since we proceed from the assumption that the materials of the piezoelectric element and structure are elastic, it seems reasonable to take into account energy losses due to the internal loss mechanisms both in the piezoelectric material and in the material of the main structure. The mechanisms of losses in piezoelectric materials have been studied for a rather long time, and in the literature there have been many relevant studies (Ala et al, 2014a, 2014b; Chen et al, 2006; Dong et al, 2017; Holland, 1967; Sherrit (1999); Uchino et al, 2011; Yuan et al, 2018). Holland (1967) and Uchino et al (2011) described in detail the losses in piezoelectric, which could be of three types: dielectric, elastic, and piezoelectric.…”