Vibration reduction of curved panels by active modal control

Active vibration control using modal controllers has been successfully implemented on simple structures such as beams and plates. Since the dynamic behavior of a variety of mechanical structures can be expressed in terms of modal parameters, the application of modal control concepts can be extended to structures with more complex geometries. For such structures, the evaluation of modal parameters from numerical calculations of local modes is complicated because the results strongly depend on proper boundary conditions of the truncated structure. Therefore, the modal data is identified using experimental modal analysis. The transformation of the experimentally measured mode shapes into closed-form analytical formulations and the extraction of modal input and output factors for sensors and actuators are used to connect experimental modal analysis with modal control theory. The implementation of the input and output factors in a modal state space formulation results in a modal filter for the point sensor array and a retransformation filter for the segmented actuator patches. In this study, PVDF film is used for sensors and actuators. The modal controller is implemented on a digital controller board, and experimental tests with the floor panel and center panel of a car body are carried out to validate the proposed concept.