Vibration tests of new damage sensors for aeronautical composite structures

Abstract

This study investigates the feasibility of implementing a solid-state sodium battery as a sensing element for vibration-based structural health monitoring (SHM) for aeronautical composite structures. A PPS composite beam was analysed through numerical analysis and experimental studies under undamaged and various pseudo-damage conditions. Structural dynamics were characterised using FRFs from accelerometers and PSDs from the battery signal. The results show strong agreement across the numerical and experimental methods, with a discrepancy ranging from 2% to 8% between the experimental methods and slightly higher but within a tolerable range (3-11%) for the battery and numerical model. The battery sensor effectively identified dominant resonance frequencies and tracked modal shifts due to structural damage.

Damage detection used frequency-based metrics (DI, CMPM, CMRM) on both accelerometer and battery signals. Battery-signal-derived SHM metrics were sensitive to structural modifications and capable of distinguishing between different damage states. While the battery has certain limitations, such as electrical interference, at the current phase of study, and offered lower accuracy compared to accelerometers, it consistently detected global dynamic changes. Overall, the batteries show promise as a self-powered vibration sensor for detecting global structural changes.