국부 감육된 압전 RL 션트 패널의 동조이탈 및 재동조가 음향 저감 성능에 미치는 영향

키워드

확장요약문

Structural changes can detune a resonant piezoelectric RL shunt and affect its attenuation performance. This study quantifies the effects of local thinning location and area on shunt detuning and evaluates the need for selective retuning based on the loss and recovery of acoustic attenuation. A fully clamped plate with a bonded PZT patch was modeled with finite thinning regions. The electromechanical response, including residual-mode contributions, was obtained using the Rayleigh–Ritz method, and sound radiation power was calculated using the Rayleigh integral. Thinning ratios of 0.10–0.30 and area ratios of 0.04 and 0.09 were evaluated at locations with low and high first-mode sensitivities to local thinning. For each condition, the healthy-state circuit was compared with a circuit retuned according to the natural-frequency ratio. The natural-frequency shift and detuning depended on the thinning location and area. Figure 1 shows that representative local thinning shifted the terminal-voltage resonance and changed the FRF shape. Figure 2 shows that retuning reduced the maximum force-normalized sound radiation power and recovered acoustic attenuation. For the representative high-sensitivity condition, the first natural frequency decreased by 4.69%, and retuning increased acoustic attenuation from 4.49 to 10.60 dB. This approximately 6 dB retuning gain persisted across the tested Ritz basis orders, whereas the small gains obtained under low-sensitivity conditions were not numerically consistent. Retuning was effective when the frequency shift was large but provided limited improvement when the shift was small. Its benefit also decreased with increasing structural damping. Retuning should therefore be determined from frequency shift, structural damping, required acoustic performance, and numerical sensitivity.