The influence of piezoelectric fibers on energy harvesting characteristics in piezoelectric composite MFC

Macro-fiber composites (MFCs) have garnered significant attention in the field of vibration energy harvesting due to their remarkable flexibility and energy conversion efficiency. This paper systematically examines the influence of a single piezoelectric fiber and its size on the energy harvesting characteristics of MFC by establishing an electromechanical coupling finite element model under the d31 working mode. The simulation results indicate that as the number of piezoelectric fibers increases, the output voltage of MFC follows a non-monotonic trend, initially increasing and then decreasing. The peak output occurs in the first-order bending mode. When n = 10 (where the piezoelectric phase volume fraction is 39.36%), the output voltage in the first-order bending mode reaches 20 V. Although an increase in the elastic modulus of the matrix enhances structural stiffness, it also restricts the strain freedom of the piezoelectric fibers, leading to a decrease in high-frequency energy conversion efficiency. This study reveals the dynamic interaction mechanism between the fiber-matrix interface mechanical coupling and polarization uniformity, providing a theoretical basis for the customized design of MFC energy harvesters.