Repetitive superposition performance of stress waves in control module of projectile under dynamic impact.

During projectile launch or penetration, the control module (CM), as the brain of projectile, endures high dynamic impact, yet stress wave analysis in CM protection remains limited. This paper develops a self-designed projectile-control module device instrumented with polyvinylidene fluoride (PVDF) sensors placed at the front, middle, and rear sections of epoxy resin (EP) in the CM cavity for quantitative stress wave measurement. Split Hopkinson Pressure Bar (SHPB) tests with and without a transmission bar are conducted to reveal stress wave reflection and superposition. Air cannon tests and numerical simulations systematically investigate influencing factors, including acceleration amplitude and boundary constraints. Results show that wave impedance mismatch at the SHPB/EP interface causes superposition of incident and reflected waves, making the rear stress 30-100% higher than the front stress at different acceleration levels. Increasing pulse width induces multiple reflections, and a novel stress wave propagation process specific to the CM is proposed. The propagation performance shows significant pulse-width dependency, offering guidance for electronic component layout inside the CM.