Piezo Sensors Based Operational Strain Modal Analysis for SHM

Abstract

AbstractPiezo sensors are a class of smart material based dynamic stain measuring sensors which are yet to be thoroughly investigated for modal analysis based global level monitoring. Operational modal analysis is a vibration testing technique to obtain the modal parameters under low amplitude operational excitation forces. This study investigates and evaluates the efficacy of piezo sensor for structural health monitoring with operational strain modal analysis. A scaled-down bridge prototype was tested under pedestrian motions to capture and locate the artificial damage at different locations. Modal frequencies, damping ratios and modes shapes are identified in healthy and damaged states and compared to localize the damage. Piezo sensors are able to detect and localize the damage effectively and are found to be superior to the accelerometers for sensitivity towards the damage. Modal assurance criteria (MAC) is estimated to compare the mode shapes and localize the damage. MAC successfully captures and localize the damage due to change in the mode shapes. The strain modes from piezo sensors are more sensitive towards the damage, and hence, they are effectively able to capture and identify the damage under low amplitude operational force based ambient excitations.KeywordsPiezo sensorsStrain modal analysisModal assurance criteriaOperational modal analysisStructural health monitoring