[Case Studies] Application of Power Amplifiers in Research on Ultrasonic Guided Wave Testing

About Ultrasonic Guided Waves

Ultrasonic guided waves are ultrasonic waves that propagate along a specific path, usually within a waveguide structure formed along boundary conditions inside a structure (such as pipes, plates, etc.). They utilize the geometric characteristics and material properties of the structure to guide the propagation path of the sound waves, enabling rapid large-area scanning of the entire structure; improving inspection efficiency; and reducing inspection costs. They are particularly suitable for health monitoring and damage detection of large structures (such as pipelines, bridges, aircraft fuselages, etc.).

Power amplifiers can accurately amplify the weak electrical signals output by signal generators to sufficient power to drive transducers to generate strong and stable ultrasonic guided waves. Without the enablement provided by power amplifiers, research such as long-distance detection and quantitative defect analysis using ultrasonic guided waves would be impossible.

Experimental Case Showcase

▼Application of Power Amplifiers in the Analysis of Guided Wave Scattering Characteristics in Bent Pipes Using Normal Mode Expansion

In this experiment, the normal mode expansion method was used to study the scattering of waveguides in bent pipes. The test pipe is the same as that used in the "Numerical Verification of Biorthogonality Relations" section; the stainless steel pipe was bent 90° in its middle by thermal bending. A 5-cycle 30kHz tone burst was generated by an arbitrary function generator, followed by amplification by the high-voltage power amplifier ATA-3080. Then, the amplified signal was sent to the transmitting transducer to excite longitudinal guided waves in the pipe.

▼Application of High-Voltage Amplifiers in Damage Localization and Evaluation of Composite Plates Based on Ultrasonic Guided Waves

This experiment is based on ultrasonic guided waves for damage localization and evaluation of composite plates, with an input signal center frequency of 80kHz. The ultrasonic guided wave signal was sampled at a rate of 10MHz, the excitation voltage was set to 20V, and then its peak was boosted to 80V through a high-voltage amplifier. The amplification rate of the preamplifier was set to 60dB. To simplify data set acquisition, additional mass blocks were considered to simulate actual damage.

▼Application of Broadband Amplifiers in Ultrasonic Guided Wave Ice Detection

In this experiment, the quantitative identification method of aircraft icing using ultrasonic guided waves can significantly improve the safety of aircraft operation. To verify the validity of numerical simulations, a static/dynamic ice detection experimental system was developed to evaluate the feasibility of Lamb wave-based ice detection under spray conditions. In addition, wavelet transform, Hampel median filter, and moving average filter were used to analyze transit time and detection time signals. Finally, it was experimentally verified that ultrasonic guided waves can achieve effective identification of ice accretion volume during the dynamic icing process.

▼Application of High-Voltage Amplifiers in the Study of Coupled Effects of Ambient Temperature and Structural Stress on Guided Wave Propagation Characteristics Coupling

In this experiment, a dispersion analysis model for plate and shell structures with temperature-stress coupling was proposed. An ultrasonic guided wave experimental system was employed to measure the phase velocity changes of different guided wave modes under the coupled action of ambient temperature changes and structural stress, in order to verify the accuracy of the dispersion analysis model.

▼Application of High-Voltage Amplifiers in Exciting a Single SH(0,1) Mode in Finite-Width Plates Using Piezoelectric Patches

This study focuses on the propagation characteristics of Shear Horizontal guided waves (SH waves) in Narrow Plates with finite Width (NPW), specifically the pure excitation of the SH(0,1) mode. By designing a d24-type PZT transducer, the influence of its length (Lp) on the excitation effect of the SH(0,1) mode was explored. Combined with simulation and experiments, its feasibility in applications such as high-temperature wall thickness monitoring was evaluated.

▼Application of High-Voltage Amplifiers in Ultrasonic Guided Wave Full Wavefield Corrosion Imaging

In this experiment, an arbitrary waveform generator was used to generate a 400kHz 5-cycle sine pulse signal modulated by a Hanning window. This was further amplified by an ATA-2022B high-voltage amplifier to drive a PZT piezoelectric patch to generate ultrasonic guided waves. A laser vibrometer was used to record the ultrasonic guided wave full wavefield data on the specimen surface for signal processing and defect imaging.