Application Cases

Experimental Name: Guided Wave Propagation and Debonding Delamination Verification Experiment Based on HSP Specimens and PZT Transducers

Research Direction:
Investigating the correlation mechanism between high-frequency guided wave dispersion characteristics and debonding delamination damage in honeycomb sandwich panels (HSP), as well as optimizing monitoring methods. A periodic structural model is constructed using the equivalent transformation method, and simulations are employed to quantify the influence of guided wave wavelength and honeycomb core dimensions on dispersion characteristics. Furthermore, a solid finite element model and PZT sensing experiments are used to validate the "debonding-induced wave-splitting" propagation characteristics of high-frequency guided waves, revealing the damage-sensitive mechanism whereby debonding delamination leads to a significant increase in Ao mode amplitude. By proposing the time-domain response of the Ao mode under high-frequency excitation as a characteristic parameter, precise identification of debonding delamination is achieved, offering a highly sensitive and low false-alarm-rate engineering solution for structural health monitoring of HSP in fields such as rail transportation and aerospace.

Experimental Objectives:
First, theoretical modeling and finite element simulations are employed to explore the influence of the ratio between guided wave wavelength and the side length of the honeycomb core unit cell in honeycomb sandwich panels on dispersion characteristics, guided wave mode propagation paths, and energy distribution. Subsequently, based on a solid finite element model and PZT sensing experiments, a validation scheme is designed to address the "wave-splitting effect" induced by debonding delamination. Comparative experiments using aluminum HSP specimens with prefabricated debonding regions quantify the changes in the time-domain amplitude characteristics of the Ao mode under debonding conditions, validating the sensitivity and reliability of high-frequency guided waves for detecting debonding damage.

Testing Equipment:
Signal generator, oscilloscope, ATA-2021B high-voltage amplifier, PZT transducers, HSP specimens, computer

Experimental Procedure:
First, computer simulations were used to model the propagation behavior of acoustic waves in honeycomb sandwich panels. It was discovered that when the acoustic wavelength is less than five times the size of the honeycomb cells, the waves tend to propagate primarily along the material's surface, and traditional theoretical models become invalid. Based on this finding, aluminum honeycomb panel specimens with prefabricated "debonding" damage were fabricated, and an array of seven miniature sensors was deployed on the specimen surface. A signal generator produced a 100 kHz detection wave, which was amplified to drive the sensors for wave transmission, while the reflected signals were received.

Figure 1: Physical Image of the Experimental System

Figure 2: Block Diagram of the Experimental System

Experimental Results:
When the acoustic waves passed through the debonded region, the amplitude of a specific wave mode (Ao mode) increased significantly by 48%, while the energy of other waveforms attenuated by 35%. This "amplitude increase" phenomenon was found to be proportional to the size of the debonded area, serving as a clear indicator for detecting hidden damage. Through multiple tests, 100 kHz was determined to be the optimal detection frequency, with an Ao mode amplitude increase of 30% set as the threshold for damage identification.

Figure 3: Time-Domain Signal Comparison Between Debonded and Healthy HSP

Figure 4: Comparison of Excitation and Sensing Signals

Figure 5: Dispersion Curve of HSP Structure

Product Recommendation: ATA-2021B High-Voltage Amplifier

Figure: ATA-2021B High-Voltage Amplifier Specifications and Parameters

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