A System Response-Based Inversion Framework for Impact Pressure Measurement Using PVDF Sensors

Accurate reconstruction of transient pressure histories using polyvinylidene fluoride (PVDF) sensors is challenging because the measured electrical signals are influenced by both circuit dynamics and the time-dependent mechanical response of the measurement system. This study proposes a system response-based inversion framework that accounts for the combined effects of the sensing element, encapsulation structure, contact interfaces, and signal acquisition circuit. By reducing the electrical response time relative to the mechanical response time, the electrical and mechanical contributions are approximately decoupled. The effective system response is characterized using a first-order Prony series, with its parameters identified through split Hopkinson pressure bar (SHPB) calibration and direct Laplace-domain fitting. Three calibration datasets and three independent validation datasets yielded normalized root-mean-square errors (NRMSEs) of 3.21–4.84% and 1.73–4.20%, respectively. The method was further evaluated through air-blast experiments at stand-off distances of 300 and 400 mm. The reconstructed peak pressures and positive-phase impulses showed reasonable agreement with PCB-derived reference values, while three repeated measurements at each distance yielded coefficients of variation below 5%. Furthermore, post-blast SHPB measurements reconstructed using the original response parameters demonstrated that the system retained its pressure reconstruction capability after blast loading. These results support the applicability, repeatability, and short-term stability of the proposed inversion framework under the investigated loading conditions.