Effect of kerf filler on the electromechanical coupling coefficient of 1–3 piezoelectric composites

• A unified formula was derived to describe the electromechanical coupling factor of 1–3 piezoelectric composites.
• The effect of different kerf filler on the electromechanical coupling factor was analyzed.
• Coupling factor decreases with the increase of the elastic stiffness of the kerf filler.
• Compared with proposed model, cylinder model tends to provide higher coupling factor with the same volume fraction (0.3 ≤ G ≤ 4).

A unified formula has been derived to quantitatively describe the electromechanical coupling factor for the thickness mode of 1–3 piezoelectric composites with rectangular rod. The effect of different kerf filler on the electromechanical coupling factor is analyzed by varying the aspect ratio of piezoelectric rod and the elastic stiffness of kerf filler, respectively. The results show that the coupling factor decreases with the elastic stiffness increase of the kerf filler. In addition, we have also compared the current rectangular rod model with previous cylinder model for 1–3 piezoelectric composites. It was found that the circular cross-section piezoelectric rod tends to provide higher electromechanical coupling factor than the square rod when the aspect ratio is between 0.3 and 4 in the 1–3 composites with the same volume fraction.