Application Cases

Experiment Name: Piezoelectric Ultrasonic Guided Wave Non-Destructive Testing Experiment

Research Direction:
As an indispensable transportation tool in modern industry, pipelines play a critical role in numerous sectors such as petrochemicals, power generation systems, steel metallurgy, and nuclear industries. Pipe wall thickness is a key parameter for evaluating the structural health of pipelines. To ensure the normal operation of pipeline systems, regular inspections or long-term online monitoring of pipe wall thickness are essential. With continuous advancements in industrial technology and production requirements, conventional pipeline wall thickness testing methods—such as ultrasonic testing, magnetic flux leakage, and eddy current testing—have shown limitations in adaptability and accuracy when facing complex working conditions like high temperatures and high pressures. Consequently, developing more accurate and efficient pipeline wall thickness testing technologies has become a focal point of current research.

Non-destructive testing methods based on ultrasonic guided waves, which direct ultrasonic waves into the pipe wall, enable comprehensive and precise assessment of structural health issues such as corrosion and defects. This approach makes it possible to inspect and monitor pipe wall thickness under extreme conditions, such as high-temperature and high-pressure environments. Compared to Lamb waves in ultrasonic guided waves, Shear Horizontal (SH) waves exhibit fewer mode conversions, lower dispersion, and reduced attenuation in plate and pipeline structures. These advantages make SH waves an ideal subject for research, garnering increasing attention from researchers worldwide in the field of high-temperature thickness testing in recent years.

Experimental Objective:
To validate the propagation characteristics of SH waves under practical conditions, providing a foundation and preliminary verification for subsequent experiments.

Test Equipment:
High-voltage amplifier, signal generator, oscilloscope, stainless steel rectangular waveguide bar, excitation probe, receiving probe, etc.

Experimental Process:
Four ATA-2022B high-voltage amplifiers were cascaded. A pulse signal generated by the signal generator was input into the eight signal input channels of the four amplifiers. The four amplifiers were synchronized, with the master unit setting parameters and the three slave units synchronizing to the master’s settings, enabling precise control of the eight output channels. The excitation signal was amplified without distortion by the high-voltage amplifiers to achieve a peak-to-peak amplitude of 200 Vpp and a frequency of 500 kHz. This signal was applied to the excitation probe. The eight groups of signals, with time delays, were applied to the piezoelectric array to excite guided waves of the specified mode. Meanwhile, the signals from the receiving probe were observed using an oscilloscope to study the transmission characteristics of the guided waves in the waveguide bar.

Experimental Block Diagram:

Figure 1: Block Diagram of the Piezoelectric Ultrasonic Guided Wave Non-Destructive Testing Experiment

Experimental Results:

Figure 2: Excitation and Received Signal Diagram

To facilitate observation of the received signal curve, the signal within the 0–130 μs time domain was partially amplified, resulting in the curve image of the excitation signal and the first received signal, as shown in Figure 2. Based on the time interval between the peaks of the excitation signal and the first received signal, the wave velocity of the SH0 guided wave excited in the experiment was calculated to be 3,134.18 m/s.

Reasons for Selecting This High-Voltage Amplifier:

• Supports master-slave cascading

• Multi-channel output capability

• High voltage accuracy

• Wide bandwidth

• Excellent output waveform quality

• Simple operation and convenient adjustment

Recommended High-Voltage Amplifier: ATA-2022B

Figure: ATA-2022B High-Voltage Amplifier Specifications

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