Flexible PVDF film sensors for buried dry-sand explosion pressure: Calibration and validation under normal/hypergravity conditions

作者：Chengpeng Hong, Guanwen Liang, Longhua Guan, Haoran Fu, Ruitao Tang, Yunmin Chen · 发表于：Defence Technology · 年份：2025 · DOI：10.1016/j.dt.2025.11.023 · 被引用次数：2 · 研究领域：Structural Response to Dynamic Loads、Geophysics and Sensor Technology、Seismic Waves and Analysis

Accurate measurement of buried dry-sand blast pressure remains a critical challenge in military protection and geotechnical engineering. In hypergravity model tests, conventional impact-type sensors exhibit size-dependent distortion of the rising edge and degraded repeatability due to high-frequency interference. To address these issues, a flexible PVDF thin-film sensor tailored for granular media was engineered by combining rotating polarization with edge depolarization to enhance piezoelectric uniformity, together with a PDMS acoustic-impedance-matching layer to mitigate interfacial reflections and power-frequency noise. Sensors were calibrated using a split Hopkinson pressure bar. Under normal gravity, a quantitative relationship between sensing-unit size and signal response in sands of differing gradation was established, revealing an optimal matching size of 5–6 mm that balances peak amplitude and repeatability. Constant-gravity sand-impact tests comparing encapsulation schemes verified that PDMS coupling reduces power-frequency interference and suppresses spurious peaks. Centrifuge buried-explosion tests further confirmed stable capture of a characteristic waveform—pronounced transient peak, rapid decay, and a multi-oscillation tail—with measured peak pressures within ∼10% of theoretical predictions. The integrated approach—uniformly polarized PVDF, PDMS impedance matching, and size–gradation matching—enables high-fidelity, low-disturbance pressure measurements in granu...