Lead zirconate titanate (PZT) and Shape memory alloys (SMA) smart composites have been previously investigated for use as actuators. SMAs exhibit a high actuating strain but responds slowly, while PZTs supply small actuation with a fast response. The composite can be tailored to control its shape when subjected to different loads, thus leading to multiple functions actuators. In this study, the concept is applied in the design of energy harvesting devices for self-tuning and control of the output response. The material type and the composite fractions properties can be optimized to tune the system’s response in order to achieve maximum output and to compensate for the external environmental effects such as temperature.
In this paper, the energy harvesting capabilities of a cantilevered composite beam, containing piezoelectric ceramic and shape memory alloy cylindrical inclusions, are studied. The system is subject to base excitation input load. Only non-prestrained SMA inclusions are considered. A model based on the mean field theory, linear piezoelectricity, and one dimensional constitutive behavior of shape memory alloys is developed to describe the effect of SMA inclusions on the time and the frequency response of the composite. The PZT and the matrix behaviors are considered linear. The overall response of the composite is highly non-linear due to the phase transformation within the SMA inclusions. A preliminary analysis of the variations of the frequency response, the time response, the power output, and the efficiency of the device with respect to the materials fractions is presented. The temperature effects are also investigated.