Application Cases

Experiment Name: Study on the Attenuation Characteristics of Ultrasonic Guided Waves in Rails

Research Direction: Ultrasonic Testing

Experimental Content: As a solid medium for sound propagation, rails have good acoustic waveguide properties. Therefore, ultrasonic signals can be used to detect internal damage in rails. Mechanical waves are used as detection signals, so they are largely unaffected by the electrical parameters of the rail or traction return current. The equipment is simple in principle, safe and reliable, easy to install and maintain, and its power consumption is relatively low compared to other detection technologies. It is suitable for real-time rail condition monitoring in sections with poor overall trackbed, tunnels, track parameters, and severe dampness and water accumulation on railway sites. It is also suitable for breakage detection of long-distance seamless rails.

Testing Equipment: ATA-4012 high-voltage power amplifier, arbitrary function generator, oscilloscope, etc.

Experimental Procedure: The detection system generally consists of piezoelectric transducers and signal transmitting and receiving modules. The signal transmitting module applies a high-voltage pulse excitation signal to the guided wave transducer on the rail. The piezoelectric transducer generates an ultrasonic guided wave signal through the inverse piezoelectric effect. The ultrasonic guided wave is transmitted through the rail and received by the ultrasonic guided wave transducer at the receiving end. The collected signal at the receiving end is characterized, or the system detects whether the corresponding ultrasonic guided wave signal is received within a given time, thereby determining the integrity of the rail in the detection interval.

Experimental Results:
Common types of damage in high-speed railways include wave-like wear, tread contact fatigue cracks, internal cracks, and internal weld defects. The ultrasonic guided wave rail breakage monitoring system is primarily designed to detect internal rail cracks, internal weld defects, and rail fractures. Ultrasonic guided wave receiving nodes are arranged near seamless rail welds. When a defect occurs inside the rail weld, the receiving node receives reflected waves from the weld defect. When a rail fracture occurs within the detection interval, the receiving node will not receive the ultrasonic guided wave signal from the transmitting end. When an internal crack appears in the rail within the detection interval, the ultrasonic guided wave signal at the receiving node will exhibit significant attenuation. Additionally, numerous rail bolt holes on the railway site can also cause attenuation of the ultrasonic guided wave. The field installation of the ultrasonic guided wave rail breakage monitoring system must consider the influence of rail bolt holes on guided wave attenuation. This experiment provides theoretical guidance for the setup and installation of seamless rail breakage monitoring systems, reducing the false alarm rate of existing seamless rail breakage monitoring systems.

High-Voltage Power Amplifier Recommendation: ATA-4012C High-Voltage Power Amplifier

Figure: Specifications of the ATA-4012C High-Voltage Power Amplifier