A numerical and experimental investigation on passive piezoelectric shunt damping of mistuned blisks

In a previous study, we proposed a method for the damping of rotationally periodic structures, when a specific mode with n nodal diameters is targeted. The proposed method considers 4n lead zirconate titanate patches (or a multiple of) which can be, either, shunted independently on 4n identical resistor–inductor circuits, or mounted in two parallel loops and shunted on only two resistor–inductor circuits. Both configurations offer the same performance; however, the parallel configuration requires only two inductors and it is aimed to reduce the demand on inductors; it works actually like a spatial filter and assumes a perfectly symmetric structure with harmonic mode shapes in the circumferential direction. The study presented in this article is aimed at evaluating the proposed damping technique in the presence of blade mistuning. In the first part, the parallel and the independent configurations are compared numerically on a set of mistuned bladed drums with controlled level of mistuning. In the second part, the parallel and the independent shunts are implemented experimentally on a mistuned bladed drum mock-up. For the considered mock-up, the numerical results show that for moderate levels of mistuning, the parallel shunt performs almost like the independent shunt, while the experimental results confirm this fact.