engleski

Identification of Damping Using High-Speed Camera

The use of high-speed cameras in structural dynamics provide contact-less measurements of displacements with a high spatial resolution, which enables measurements of a full-field response from a distant objects. Identification of modal parameters is a usually performed in monitoring of distant structures. Damping identification is a demanding task, even with high-dynamic-range sensors (accelerometers). Response obtained from high-speed camera has relatively small dynamic range and are contaminated with a relatively high level of noise. On the other hand, image-based techniques have the advantage of providing full-field structural identification which can be utilized to enhance identification data. Damping is modal parameter which, theoretically, is not spatially dependent. In this research we have used spatial over-determination to increase the accuracy of the damping identification which is based on the Morlet-wave damping identification method. The MWDI method is based on the Continuous Wavelet Transform, but it is significantly faster. The full-filed damping identification results were averaged with regard to the identified deflection shapes. The method was tested experimentally on the simple structure up to 2.5 kHz. It was found that the results are comparably accurate to the damping identified using the high-dynamic-range and low-noise piezoelectric accelerometer, proving that damping can be accurately identified from high-speed-camera measurements.

Morlet-wave ; spatial damping ; full-field

nije evidentirano