利用压电自传感驱动器进行裂纹钢梁损伤识别的实验研究

EXPERIMENTAL STUDY ON DAMAGE IDENTIFICATION IN A CRACKED BEAM THROUGH PIEZOELECTRIC SELF-SENSING ACTUATORS

压电陶瓷是一种智能材料,可以在结构健康监测系统中同时用作传感器和驱动器。基于压电阻抗的损伤识别技术的基本原理,对裂纹钢梁进行了损伤识别和定位的实验研究。将三片压电陶瓷(PZT)粘贴在钢梁表面的不同部位作为驱动器和传感器,通过测量梁损伤前后压电陶瓷片的电阻抗变化来识别梁中的裂纹损伤。从导纳(阻抗的倒数)幅值谱曲线中提取裂纹梁的反谐振频率,通过比较各压电片位置的反谐振频率变化识别了裂纹位置;同时比较不同损伤工况下的反谐振频率变化定性地识别裂纹梁结构的损伤程度。

Piezoelectric ceramic is one of smart materials,which can be acted as a sensor or/and an actuator for structural health monitoring.The piezoelectric impedance technique for damage identification is addressed.An experimental study on damage identification and localization in a cracked beam is implemented based on the piezoelectric impedance technique.Three pieces of piezoelectric ceramic sheets(PZTs) are bonded to different positions on top surface of a steel beam,and each PZT is used as an actuator and a sensor simultaneously,and presence and position of a crack damage are identified with variations of electrical impedance measurements.The anti-resonant frequencies at the positions where the PZTs are bonded are attained from the amplitude spectral curves of piezoelectric admittance(inverse of impedance),and the location and the extent of the crack damage are identified by comparing the variations of anti-resonant frequencies at different positions or in different modes.