Abstract
Identification method for the nodal lines of a plate by one sensor is proposed. From the theory of vibration of a single DOF system, increasing the frequency of excitation through the resonance point converts the phase angle between the excitation and the response from in phase to 180 degrees out of phase. In the vibration of continuous system, responses have opposite direction in both side of nodal line. These properties make the anti-resonance points, which correspond to nearly zero amplitude between two resonance points in the frequency response function. The nodal lines of a plate can be identified by the anti-resonance points. The power spectrum of the response subjected to impulse force hammer is similar to the frequency response function, because the impulse force has almost uniform frequency components. Using the shape of the minimum points of power spectra of the responses of the repeated measurements by one sensor, successful identification of the nodal lines of a plate is demonstrated in this paper. It is shown that the identified results by the proposed method are equivalent to the results by the anti-resonance points, and agree well with the FEM results.
