Characterization of metal-core piezoelectric fiber/aluminum composite in a large-strain region

Abstract

To evaluate the suitability of metal-core piezoelectric fiber/aluminum composites for structural health monitoring, their output characteristics and mechanical properties were evaluated in large strain regions exceeding 10%. Tensile vibration tests were adapted to the composites to evaluate the output charges in large strains; simultaneously, the mechanical properties were evaluated. Consequently, it was possible to obtain outputs even at approximately 20%, and the output was divided into three stages. The fracture behavior of the fiber was related to the change in output. The first stage involves the region where fiber fragmentation occurs due to mechanical load on the fiber and the fragmentation reduces the stress, resulting in a decrease in output charges. The second stage is a region where the fragment length reaches a critical length and the stress transmitted from the matrix becomes constant, resulting in a constant output. The third stage involves a sudden decrease in output due to core rupture. Further, the effect of residual stress was confirmed. The Weibull distribution of fiber strength, decreased with relaxation of the residual stress in the scale parameter from 9.31 MPa to 6.36 MPa, indicating that residual stress has a significant effect on the mechanical properties of the fiber.