Application Cases

Experiment Title：Application of Power Amplifier in Health Monitoring of Bolted Spherical Joints Using Piezoelectric-Based Active Sensing Technology

Experiment Objective：To verify that the time-reversal method employing piezoelectric ceramic sensors can effectively monitor the connection status and stress state of bolted spherical joint zones.

Experiment Equipment

• Power amplifier: ATA-2022H

• Piezoelectric ceramic (PZT) sensors

• Bolted spherical joint

• Sleeve

• Data acquisition (DAQ) card

• Laptop workstation

Experiment Overview：
This experiment validates a time-reversal-based health monitoring technique for bolted spherical joints via scaled model tests. The peak amplitude of the time-reversal focused signal depends solely on the transfer function of the propagation path. Damage or improper installation of the internal bolt (e.g., loosening, misalignment) alters this transfer function, thereby shifting the focused signal’s peak.

Experiment Procedure：

1. Forward Path: A generated signal is amplified by the ATA-2022H and excites PZT1 bonded to the spherical joint. The signal propagates through the joint and sleeve to the attached member, where PZT2 acts as a receiver. The captured signal is digitized by the DAQ card and processed in LabVIEW.

2. Time Reversal: The recorded signal is time-reversed and re-emitted by PZT2. This reversed signal back-propagates through the member and sleeve to the spherical joint, converging into a focused peak detected by PZT1. The resulting waveform is displayed and analyzed on the laptop.

ATA-2022H Integration：
The ATA-2022H power amplifier drives the PZT actuators during both forward excitation and time-reversal stages, ensuring sufficient signal amplitude for structural interrogation.

Experiment Results：

• Peak Focused Signals: Comparative plots for noise-free and noisy environments.

  
  

• Axial Force Correlation: Variation in focused peak amplitude under increasing member axial load.

Experiment Conclusion：
The time-reversal method yields consistent monitoring results regardless of noise presence, demonstrating robustness against environmental disturbances (e.g., wind, construction loads, sensor noise). This noise immunity validates its suitability for real-world structural health monitoring of bolted spherical joints.