Damage detection technique for structure based on FRF data generated by harmonic excitation force

摘要

A technique for detecting damage to structures is proposed that uses FRF data generated by the harmonic excitation force. It is based on the fact that structural damage usually causes a decrease in structural stiffness and an increase in structural damping, thereby producing change in vibration characteristics. This change in vibration responses provides useful information about the location and severity of the damage done. Damage identification equations were established by comparing the equations of motion of the structure before and after damage. The proposed technique using harmonic excitation is advantageous in that we know the input force exactly, compared to other methods that use unknown ambient excitation. Therefore we can use both input and output data for identification. When the number of measurements was insufficient, the iteration scheme, which iteratively reduce the number of unknown parameters by excluding the elements assessed undamaged from damage candidates, was introduced. The results of numerical simulations and field measurements are presented to assess the validity of the proposed technique.