A Piezoelectric Dam** Support for the Vibration Suppression of Rotors

Abstract

Elastic supports are widely used in flexible rotors of aero-engines. The principal function of elastic support is to provide the rotor with reasonable stiffness, on one hand to balance the inertia force of the rotor, on the other hand to reduce the stress on the shaft. To further suppress the excessive vibration when crossing the critical speed, dampers are generally mounted on the support. Piezoelectric materials have the advantages of strong electromechanical coupling capability and wide bandwidth. When the thickness of piezoelectric material is comparable to that of the substrate structure, it exhibits good dam** performance. The main drawback is that piezoelectric materials cannot withstand too much loads. In this study, we propose the concept of a piezoelectric dam** support for suppressing rotor vibration. The elastic support structure, distributed with piezoelectric materials, is utilized solely for generating dam** rather than providing stiffness. An S-shaped elastic ring is designed to enhance the electromechanical coupling effect. The attached piezoelectric patches are grouped and interconnected with the synchronized switch dam** on inductance (SSDI) to dissipate the vibration energy. The purpose of this work is to study the feasibility of the proposed piezoelectric dam** support. To do that, the following works are carried out: (1) An elastic ring support based on S-shaped spring structure is designed, which ensures both the uniformity of radial stiffness and the rotationally periodic symmetry of strain distribution; (2) a numerical simulation is conducted for the rotor system to evaluate the dam** performance. Results show that the novel dam** support has high electromechanical coupling factor, and the dam** effect is considerable for the rotor system. Towards engineering applications, the piezoelectric dam** support can be installed in areas where deformation is suitable, and it can function in parallel with traditional elastic supports that primarily provide stiffness. Moreover, in contrast to the squeeze film damper, this dam** support is oil-free.

Appendix

1.1 A. Material Properties of PZT-5H

$$ \left[ {{\textbf{c}}^{\text{E}} } \right] = \left[ {\begin{array}{*{20}c} {\begin{array}{*{20}c} {126} & {79.5} & {84.1} \\ {79.5} & {126} & {84.1} \\ {84.1} & {84.1} & {117} \\ \end{array} } & {\begin{array}{*{20}c} {\,} & {\,} & {\,} \\ {\,} & {\,} & {\,} \\ {\,} & {\,} & {\,} \\ \end{array} } \\ {\begin{array}{*{20}c} {\,} & {\,} & {\,} \\ {\,} & {\,} & {\,} \\ {\,} & {\,} & {\,} \\ \end{array} } & {\begin{array}{*{20}c} {23} & {\,} & {\,} \\ {\,} & {23} & {\,} \\ {\,} & {\,} & {23.25} \\ \end{array} } \\ \end{array} } \right]{\text{GPa}}\,\left[ {\textbf{e}} \right] = \left[ {\begin{array}{*{20}c} \begin{gathered} \begin{array}{*{20}c} {\,} \\ {\,} \\ {\,} \\ \end{array} \hfill \\ \begin{array}{*{20}c} {\,} \\ { - 17} \\ {\,} \\ \end{array} \hfill \\ \end{gathered} & \begin{gathered} \begin{array}{*{20}c} {\,} \\ {\,} \\ {\,} \\ \end{array} \hfill \\ \begin{array}{*{20}c} { - 17} \\ {\,} \\ {\,} \\ \end{array} \hfill \\ \end{gathered} & \begin{gathered} \begin{array}{*{20}c} {10} \\ {10} \\ { - 25} \\ \end{array} \hfill \\ \begin{array}{*{20}c} {\,} \\ {\,} \\ {\,} \\ \end{array} \hfill \\ \end{gathered} \\ \end{array} } \right]{\text{C/m}}^{2} $$

$$ \left[ {{\varvec{\upvarepsilon }}^{\text{S}} } \right] = \left[ {\begin{array}{*{20}c} {1700\varepsilon_0 } & {\,} & {\,} \\ {\,} & {1700\varepsilon_0 } & {\,} \\ {\,} & {\,} & {1793.8\varepsilon_0 } \\ \end{array} } \right],\varepsilon_0 = 8.85{\text{pF/m}} $$

The direction of the above matrix is determined according to IEEE standard on piezoelectricity, 1988: 1–x, 2–y, 3–z, 4–yz, 5–xz, 6–xy.

1.2 B. Parameters of Rotor System

Table 1. Geometric parameters of rotor system.

Table 2. Material parameters of rotor system.

Table 3. Finite element model parameters of rotor system.