A semi-flexible 1–1–2-type piezoelectric composite with three-component nested structures

To achieve transducing materials of high electromechanical coupling factor, high adaptability and high compatibility, this paper proposes a semi-flexible 1–1–2-type nested composite (1–1–2-type composite) composed of piezoelectric ceramics, epoxy resin and silicone rubber. Based on the uniform theory and the mixed field theory, an equivalent parameter model of 1–1–2-type composites is established, and the influence of structural parameters on the resonance parameters of the 1–1–2-type composites are analyzed. Finite element simulation is conducted on the 1–1–2-type composite to verify the effectiveness of the equivalent parameter model. The “dice-fill” technique is used to fabricate 1–1–2-type composite samples. The results show that the 1–1–2-type composite has a significant thickness vibration mode. These 1–1–2-type composites exhibit a high thickness electromechanical coupling factor, with an average value of 0.69 across all samples and a peak value reaching 0.72. Compared to traditional 1–3-type composites, this improvement can be as high as 20 %. 1–1–2-type composite combines the advantages of high electromechanical properties, high conformability, and high compatibility, along with good resistance to hydrostatic pressure, making it highly promising for the development of innovative multifunctional curved transducers and their arrays.