Application Cases

Experiment Name: Experiment on Prestress Control and Performance Testing of Piezoelectric Transducers

Research Direction: This study focuses on cylindrical and spherical prestressed piezoelectric transducers. It aims to achieve quantitative prestress application by establishing a mechanical-electrical equivalent model and optimizing the structure through finite element analysis. A fiber winding-prestress mapping relationship is developed to enable precise control. The effects of prestress on the electrical properties of piezoelectric ceramics are investigated to determine the optimal prestress and enhance acoustic radiation performance. Additionally, the thermal stability and heating mechanisms are studied to support applications in related fields.

Experimental Objectives:

1. Achieve quantitative and precise control of prestress in cylindrical and spherical piezoelectric transducers and determine the optimal prestress parameters.

2. Investigate the influence of prestress on the electrical properties of piezoelectric ceramics and the acoustic radiation performance of transducers.

3. Study the thermal stability and heating mechanisms of prestressed transducers to provide experimental evidence for their reliable application in scenarios such as concrete pile testing and marine acoustic detection.

Testing Equipment:
The instruments used in this study include a signal generator, power amplifier, infrared thermal imaging camera, four-channel temperature meter, oscilloscope, electronic torque wrench, and multifunction static strain gauge.

Experimental Procedure:

1. Fabrication of Transducers:

• PZT-4 and PZT-5 piezoelectric ceramics, along with glass fibers, were selected as raw materials.

• Uniaxial prestress was applied using a bolt structure, and two-dimensional/three-dimensional radial prestress was applied through fiber winding by controlling fiber tension and the number of layers.

• Cylindrical and spherical prestressed piezoelectric transducers were prepared.

2. Testing System Setup:

• A signal generator was used to generate excitation signals, which were amplified by a power amplifier to drive the transducers.

• An E4990A impedance analyzer measured electrical properties such as resonant frequency and dielectric loss.

• Acoustic radiation performance, including sound velocity and source level, was measured using a pile acoustic testing device and a standard hydrophone.

• An infrared thermal imaging camera and temperature meter monitored temperature changes during continuous operation.

3. Simulation and Validation:

• A finite element model was constructed using COMSOL Multiphysics to simulate stress distribution and resonant characteristics.

• Theoretical calculations were compared with experimental results to validate prestress control accuracy and performance improvements.

  
  

Figure 1: Monitoring Platform for Continuous Operating Temperature and Thermal Distribution of Piezoelectric Ceramics and Transducers

Figure 2: Changes in Surface Temperature of Piezoelectric Ceramic Cylinders Over Time Under Different Uniaxial Prestress Conditions

Experimental Results:
To clarify the effect of prestress on the thermal distribution of piezoelectric ceramic cylinders, an input electrical power of 2.86 W was applied to piezoelectric ceramic cylinders with uniaxial prestress levels of 0 MPa, 9.36 MPa, and 18.72 MPa. After 5 minutes of continuous operation, the surface temperature distribution was measured using an infrared thermal imaging camera.

The heat generated by the piezoelectric ceramic cylinders raised their surface temperatures, which was then conducted to adjacent nylon gaskets and the air. Due to the low thermal conductivity of air (0.026 W/(m·K)) and the moderate thermal conductivity of nylon gaskets (0.13–0.25 W/(m·K)) compared to piezoelectric ceramics (2–3 W/(m·K)), the nylon gaskets exhibited higher temperatures with distinct peaks.

As the uniaxial prestress increased to 18.72 MPa, the maximum temperature of the nylon gaskets rose from 34.5°C to 36.8°C, resulting in a 15°C temperature difference with the environment. This indicates that increased prestress leads to higher dielectric loss in ceramics, converting more electrical energy into thermal energy. The maximum temperature of the transducers was 2.3°C higher under prestress compared to no prestress, confirming that uniaxial prestress intensifies heating in piezoelectric ceramic cylinders.

Figure 3: Infrared Thermal Imaging of Piezoelectric Ceramic Cylinder Surfaces After 5 Minutes of Continuous Operation Under Different Uniaxial Prestress Conditions

Figure 4: Changes in Conductance Spectra of Uniaxial Prestressed Piezoelectric Ceramic Cylinders Before and After Continuous Operation

Recommended Voltage Amplifier: ATA-2088

Figure: ATA-2088 High-Voltage Amplifier Specifications

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