Lead-free piezoceramic macro-fiber composite actuators toward active vibration control systems

Macro-fiber composite actuators (MFCAs) suffer from strict restrictions on the utilization of lead-containing precursors due to growing environmental concerns. To address this issue, a novel lead-free MFCA based on potassium sodium niobate piezoceramics has been developed using the dice & fill method. The MFCA demonstrates large electric field-induced displacement (31.4 μm over -500‒1 500 V at 0.5 Hz), excellent frequency stability, and a strong linear relationship between the induced displacement and the external voltage amplitude. Meanwhile, unlike lead-based MFCA that requires superposition of a negative dc bias voltage to pursue higher output performance but risks depolarization, lead-free MFCA can achieve larger displacement by superimposing only a positive bias voltage. This device exhibits excellent reliability, maintaining a stable output over 10⁵ electrical cycles. Additionally, a “back-to-back” coupled MFCA has been developed to regulate bidirectional displacement, making it suitable for various practical applications, including active vibration control. This approach has resulted in a 90% vibration reduction and provides new insights into the design of MFCAs, further facilitating their application in active vibration control systems.