Stress Waveform Evolution in Rubber‐Modified Epoxy Resin and Dynamic Response in Encapsulation Device

A BSTRACT During projectile launch or penetration, the encapsulation device (ED) suffers severe mechanical shocks. This study employs polyvinylidene fluoride (PVDF) sensors to quantitatively measure internal stress wave propagation for the first time. Using a split Hopkinson pressure bar (SHPB) system, the stress wave propagation and waveform evolution in rubber‐modified epoxy (RMEP) with content (0%–20%) are investigated, focusing on the effects of end length (10–30 mm) and pulse duration (30–160 μs). The study features embedded multi‐point PVDF measurement inside the structure, systematic variation of end length and pulse duration, and transfer of the SHPB findings to air cannon experiment on EDs. The results demonstrate stress waveform transition from superposition to separation with increasing end length. Attenuation coefficients for RMEP0‐20 range from 3.6–10.1 m −1 . Longer pulse width shifts the superposition zone forward. The primary attenuation mechanism comprises both viscoelastic matrix damping and particle‐matrix interfacial debonding. Impedance mismatch at the rear cover causes wave reflection and superposition. For RMEP20, attenuation dominates, reducing the rear‐end stress by 18.1%–34.4% (with standard deviations of ±2.3% to ±4.1%) relative to the front end. These findings address the problem of quantifying stress wave in ED, providing a measurement method and practical guidelines for protecting electronic components.