Effects of fiber volume fraction on strain of piezoelectric fiber composites

Abstract

Piezoceramic fibers as the active deforming component in piezoelectric fiber composites have the largest influence on the overall strain of the composites. The results of this study show that the fabricated composites exhibited clearly anisotropic actuation properties. The free strain of piezoelectric fiber composites with 70 % by volume fibers in the longitudinal direction was 2.9 times of that in the transverse direction at the excitation voltage of 2 000 V and excitation frequency of 0.1 Hz. Larger fiber volume fraction can increase the free strain of the composites, e. g. in this case the free strain increased by about 24.6 % and 33.6 % in the longitudinal and transverse directions, respectively, as the fiber volume fraction increased from 70 % to 78 %. The piezoelectric strain coefficient d33 of piezoelectric fiber composites exhibits nonlinear dependency on the actuation voltage and linear dependency on the logarithm of frequency.