An innovative approach for conducting experimental modal analysis (EMA) in running harmonic for structural modal identification

摘要

This paper presents a novel approach for performing Experimental Modal Analysis (EMA) in running harmonics using the well-established Time Synchronous Averaging (TSA) technique coupled with a newly developed automatic driving impact system. A combination of an electromechanical linear solenoid and force sensor was employed to deliver periodical input on the structure. A phase cancellation strategy was adopted within TSA protocol of the output vibration signals to suppress the harmonic component for a sufficient number of block averages. Evaluation of the results obtained via the new approach with respect to conventional EMA showed high resemblance on the dynamic characteristics (i.e. natural frequency, damping ratio and mode shape). As low as 1.06 Hz shift in natural frequency and 0.07% difference in modal damping were obtained at specific mode of vibration, indicating the reliability of the proposed method to be adopted in getting the modal parameter at operational mode. (C) 2020 Elsevier Ltd. All rights reserved.