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Name of experiment：application of power amplifier in health monitoring method of piezoelectric active sensing technology

Research direction：active sensing technology

Experimental purpose：to verify that the time inversion method of piezoelectric ceramic sensor can effectively monitor the connection state and stress state of bolt ball joint.

Test equipment：ATA-2022H power amplifier, piezoelectric ceramics, bolt ball, sleeve, data acquisition card, laptop, etc

Content of experiment：in this experiment, the piezoelectric ceramic sensor is used to verify the health status monitoring method of the bolt-ball joint connection area based on the time inversion technology through the model test. The peak value of the time inversion focused signal is only related to the transfer function of the transmission path through which the signal is transmitted on the structure. When the bolts inside the bolt-ball joint are damaged or not installed in place (damaged state), which means the transfer function changes, the peak value of the focused signal will also change.

Experimental process：

In the test process, the signal is amplified by the power amplifier to stimulate the piezoelectric ceramic sensor, and the signal is transmitted to the rod through the bolt ball and sleeve. The PZT2 sensor on the rod receives the signal and transmits it back to the data acquisition card, and the laptop workstation uses LabView for time inversion processing. Then, the time inversion signal is applied to the PZT2 sensor on the rod as an excitation signal, and the reverse signal is transmitted to the bolt ball through the rod and sleeve, forming a focusing signal with a peak value. Finally, the focusing signal is received by the PZT1 on the center bolt ball node, and the signal data is displayed and processed by the laptop computer.

test equipment based on time inversion method

signal transfer diagram of time inversion analysis

Experimental result：

No matter there is noise or no noise interference, the same monitoring results appear in the connection area of bolt ball node based on the time inversion method, indicating that the method has strong noise robustness, that is, anti-noise. In the process of installation and use in actual projects, it is inevitable to be affected by wind load, construction load, monitoring test error and other factors. The good noise resistance of time inversion will ensure that the method is more suitable for engineering practice.

peak value of focus signal in noiseless condition and noisy condition

peak value of focus in noiseless condition, peak value of focus in noisy condition and axial force change diagram of rod

 ATA-2022HParameters and appearance：