Impact Experiment Study on Testing Characteristics of PVDF Piezoelectric Sensors

In order to elucidate the dynamic testing properties of polyvinylidene fluoride (PVDF) piezoelectric film sensors and improve the accuracy of stress wave measurements at the interfaces of porous media, such as aluminum foam, subjected to explosive or impact loads using PVDF piezoelectric sensors, impact experiments were performed utilizing the Hopkinson pressure bar to examine the response characteristics of PVDF piezoelectric film sensors under diverse testing scenarios. The analysis of PVDF sensor responses across various testing conditions yielded the following observations: When compared to an external resistance of $\mathbf{3 5. 9 5} \Omega$, the sensor exhibited a smoother voltage curve and a higher voltage value when the external resistance was set to $554.9 \Omega$. This led to an enhanced signal-to-noise ratio and reduced measurement error within the testing system. Regardless of the placement of a thin aluminum sheet between the incident bar and the sensor or between the sensor and the transmission bar, the original voltage waveform measured by the sensor and the electric charge waveform derived through transformation were highly similar to those obtained without the thin aluminum sheet. The inclusion of the thin aluminum sheet had no discernible impact on the stress test results. The research findings can serve as a valuable reference for the practical engineering applications of PVDF piezoelectric film sensors.