Macro Fibre Composite-Based Active Suppression of Low-Frequency and Broadband Applied in Thin-Walled Composite Beam

With the development of aerospace technology, the low-frequency noise of aircraft wings has become an urgent issue, and low-frequency noise causes aircraft wing fatigue and even leads to aircraft damage. Since the noise environment of aircraft wings is in the low-frequency range of 5–300 Hz, the existing passive vibration isolation technology has poor adaptability to low frequency. Therefore, it is urgent to have a low-frequency active vibration suppression material suitable for thin-wall structure, which requires low frequency, high response, high sensitivity and broadband. Macro fibre composite (MFC) has the advantages of low frequency, flexibility and high sensitivity. Because of its excellent mechanical and electrical coupling properties, it can effectively suppress aircraft wing noise in low-frequency active vibration suppression devices. This work proposed an MFC-based selffeedback system for low-frequency and broadband applied in a thin-walled composite beam, in which MFCs were attached on the upper and lower surface. The above MFC acted as sensors for continuously sensing the vibration signals, and the other below MFC was utilized to generate inverse vibration to suppress vibration. Optimal vibration suppression is observed at the first-order resonant frequencies of aluminum, stainless steel, and carbon fibre substrates, with suppression rates of 98.00%, 89.90%, and 81.63%, respectively. Excellent broadband vibration suppression effects are also demonstrated at non-resonant frequencies within 100 Hz. Our proposed structure for low-frequency suppression could be further extended to other thin-walled materials, such as carbon fibre plate, epoxy plate, and steel plate, opening up a new avenue in low-frequency and broadband vibration suppression.