Application Cases

Experimental Name: Vibration State Testing of Air Composite Materials

Research Focus: With the continuous advancement in information and intelligent technology requirements, piezoelectric ceramics have entered a new era of development. The emergence of piezoelectric composite materials has significantly propelled progress in fields such as medical ultrasound, underwater acoustic transducers, and torpedo detectors. Among these, 1-3 type piezoelectric composites have garnered widespread attention from researchers due to their advantages of low acoustic impedance, low density, and high electromechanical properties. The 3-2 ceramic-air piezoelectric composite is a piezoelectric material with a special structure, composed of piezoelectric ceramics and air combined in specific connectivity patterns, volume-to-mass ratios, and spatial distributions. This composite material combines the excellent piezoelectric properties of piezoelectric ceramics with the lightweight characteristics of air, resulting in unique physical and electrical properties. Due to the incorporation of piezoelectric ceramics, the composite exhibits a high electromechanical coupling coefficient, enabling efficient conversion between mechanical energy and electrical energy. The inclusion of air as a component gives the overall material low acoustic impedance, which is beneficial for the transmission and reception of acoustic waves. By adjusting parameters such as the distribution and ratio of piezoelectric ceramics to air, composites with different properties can be designed to meet various application requirements.

Experimental Objective: To verify that the 3-2 ceramic-air composite material possesses superior piezoelectric characteristics compared to the 1-3 type piezoelectric composite, providing a foundation and justification for subsequent experiments.

Test Equipment: ATA-4315 high-voltage power amplifier, signal generator, oscilloscope, laser vibrometer, etc.

Experimental Process: First, an excitation signal with a frequency range of 100 kHz to 400 kHz generated by a function generator is amplified through the ATA-4315 high-voltage power amplifier and applied across the ceramic. The thickness vibration mode of the 3-2 piezoelectric composite is observed. The vibrometer refreshes in real-time the changes in amplitude, velocity, and acceleration over time, while performing a Fast Fourier Transform (FFT) to automatically capture spectral peak information. The oscilloscope monitors the voltage changes across the ceramic. The experimental block diagram is shown in Figure 1-1.

Figure 1-1: Experimental block diagram for studying the piezoelectric characteristics of the 3-2 type ceramic

Experimental Results: As shown in Figure 1-2, under the premise of the same ceramic volume fraction, the resonant frequency of the 3-2 ceramic-air composite material is 190 kHz, which is higher than the resonant frequency of the 1-3 piezoelectric composite (162 kHz). This is because the 3-2 piezoelectric material lacks the constraint of polymer epoxy resin, allowing the piezoelectric pillars to vibrate freely, resulting in a higher vibration frequency than the 1-3 piezoelectric vibrator. At the resonant frequency, the displacement of the 3-2 piezoelectric vibrator is 3.840 nm, greater than the 2.857 nm of the 1-3 type. This occurs because positive and negative ions undergo relative displacement under the influence of the electric field force, leading to internal stress within the crystal and ultimately causing macroscopic deformation of the wafer. The charge appearing on the crystal surface is shown in Figure 1-2. Under the same ceramic volume fraction condition, the resonant frequency of the 3-2 ceramic-air composite material is 190 kHz, higher than the 162 kHz resonant frequency of the 1-3 piezoelectric composite. This is attributed to the absence of polymer epoxy resin constraints in the 3-2 piezoelectric material, allowing free vibration of the piezoelectric pillars and thus a higher vibration frequency than the 1-3 piezoelectric vibrator. At the resonant frequency, the displacement of the 3-2 piezoelectric vibrator is 3.940 nm, greater than the 2.857 nm of the 1-3 type. Due to the relative displacement of positive and negative ions under the electric field force, internal stress is generated within the crystal, ultimately leading to macroscopic deformation of the wafer and the appearance of charge on the crystal surface.

Figure 1-2: Comparison chart of vibration displacement in the Z-direction

Power Amplifier Recommendation: ATA-4315

Figure: ATA-4315 High-Voltage Power Amplifier Specifications and Parameters

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