Control of the eigensolutions of a harmonically driven compliant structure

Abstract

The motion amplitude of a harmonically driven compliant structure is maximized if the driving frequency equals one of the structural resonance frequencies. For practical use of resonating compliant structures control of the eigensolutions, i.e. eigenfrequencies and eigenmodes, is often required. In this work, a systematic way to control the eigensolutions of harmonically driven structures is presented while maintaining the advantages of a resonating structure. This control is realized using local structural modifications. Eigensolution sensitivities for these local structural modifications are used to indicate the locations for the most effective structural modifications, minimizing the required control power. This method uses the modal basis of the structure as the preferred basis. A simple harmonically driven compliant structure is used to show how local structural modifications are selected to obtain a desired change in the eigensolutions. The proposed method is found to be a convenient tool to determine effective local structural modifications to control the eigensolutions of resonating compliant structures. During the design phase it provides valuable insights in the possibilities and limitations of controlling specific eigensolutions.