Preliminary Study on Piezoelectric Sensor Signals Embedded in Polymeric Samples

Piezoelectric sensors are widely used for force and vibration monitoring in both rigid and flexible structures, yet their performance can be significantly affected by how they are integrated into the host material. Challenges such as limited sensitivity, inconsistent signal transmission, and delays in response remain particularly relevant in flexible components produced by additive manufacturing. Addressing these limitations requires a better understanding of how integration strategies influence sensor behavior. This study presents preliminary experimental results on the performance of commercial piezoelectric ceramic (PZT) sensors embedded in flexible structures fabricated by additive manufacturing (3D printing). Although the current investigation did not assess variability from mass production, repeated testing of each specimen was performed to reduce this potential error. Filaflex Foamy 95A polyurethane (TPU) samples were produced using Fused Filament Fabrication (FFF) technology in two configurations: with and without a cavity for sensor fitting. A minimum of seven valid compression tests, at each condition, were performed, with ten loading and unloading cycles up to 1000 N of force, using an indentation rate of 0.5 mm/s. In most tests, the two configurations showed different peak amplitudes throughout the cycles. Samples with the sensor embedded in the cavity consistently reached peak signal amplitudes more rapidly. In contrast, samples with the sensor positioned on the material surface without a fitting exhibited similar results across all tests and demonstrated a broader signal distribution over time. These findings indicate that the sensor-integration strategy is the primary factor influencing dynamic force transfer, impact sensitivity, piezoelectric response time, and maximum signal magnitude.