Application Cases

【Overview】
In 2025, a research team from Southwest Jiaotong University used the Aigtek ATA-2022H high-voltage amplifier in their study on guided wave propagation characteristics in straight switch rails, successfully conducting ultrasonic guided wave signal output experiments on turnout straight switch rails. A transient finite element model of the straight switch rail was established. Using a comb-shaped excitation method based on the group velocity principle, the propagation process of a single guided wave mode in the straight switch rail was numerically simulated, verifying the correctness of the wave-structure conversion algorithm for this variable cross-section structure. Based on the algorithm proposed in this paper, the dispersion information of each mode at key cross-sections of the straight switch rail was obtained, and the rainbow trapping effect in the straight switch rail was discovered for the first time. Finally, the theoretical analysis results and the rainbow trapping phenomenon in the straight switch rail were verified through experiments.

Experiment Name: Ultrasonic Guided Wave Signal Output Experiment on Straight Switch Rails

Research Direction: Testing of Guided Wave Propagation Characteristics in Straight Switch Rails

Experimental Content:
The turnout straight switch rail is an engineering structure with a variable cross-section and irregular geometry. The propagation characteristics of guided waves within it are highly complex. Even for a single guided wave mode, the amplitude distribution varies significantly across different cross-sections of the straight switch rail. By inputting high-energy guided wave signals through a power amplifier, the variation patterns of amplitude distribution and dispersion characteristics of a single mode propagating in the straight switch rail were tested, and the rainbow trapping effect in the straight switch rail was discovered for the first time.

Testing Equipment: Arbitrary waveform generator, high-voltage amplifier (Aigtek ATA-2022H), oscilloscope, piezoelectric ceramic sensors, etc.

Experimental Procedure:

Figure 1: Experimental Test System Diagram

Figure 2: Experimental Setup Photo

An arbitrary waveform generator was used to modulate a specific single guided wave mode signal. The signal was amplified by a high-voltage amplifier to form a high-energy ultrasonic guided wave signal. The piezoelectric ceramic sensors were then tightly bonded to the polished surface of the rail web of the straight switch rail, allowing the guided wave signal to be input into the turnout straight switch rail. Finally, the signals were extracted and displayed using receiving sensors and an oscilloscope. A large number of guided wave signals were received at equal intervals along the longitudinal direction of the straight switch rail to test the amplitude variation and dispersion characteristics of the guided waves in the rail.

Experimental Results:

Figure: Experimental Results

The excitation signal was a single-cycle Hanning window signal with a center frequency of 45 kHz, stably input into the turnout straight switch rail through the arbitrary waveform generator, power amplifier, and sensors. The equally spaced signal receiving points captured the changes in the signal as it propagated over distance. By applying a secondary Fourier transform to the series of frequency-domain signals, frequency-wavenumber domain information was obtained. Overlaying the cloud map distribution of the rail guided wave propagation characteristics in the frequency-wavenumber domain with the theoretically calculated dispersion curves allowed the guided wave propagation characteristics to be determined. Additionally, the wavenumber could be converted to phase velocity to compare the consistency between the cloud map distribution in the frequency-phase velocity domain and the theoretical phase velocity dispersion curves.

Advantages of Aigtek Amplifiers in This Application:

1. High voltage output capability – Provides high-energy guided wave excitation capable of penetrating the variable cross-section.

2. Wide bandwidth and high slew rate – Ensures the waveform purity of the single-mode signal.

3. Digitally adjustable precision gain and real-time monitoring – Supports fine experimental control across numerous measurement points.

Recommended Product: ATA-2022B High-Voltage Amplifier

Figure: Specifications of the ATA-2022B High-Voltage Amplifier