Influence of Gamma Radiation on Piezoelectric Active Elements of Space Systems

Abstract

As more structures enter orbit for long-term use or for short-term missions, safety of space vehicles becomes increasingly important. Structural health monitoring (SHM) can play a significant role in achieving the goal of safe space flight as well as reducing orbital debris. Before SHM is implemented in space structures on orbit, it is imperative to understand the effects of the extreme space environment on elements of the SHM system. Elastic wave propagation and electro-mechanical impedance spectroscopy are among the most promising SHM methods and could be implemented for on-orbit applications, provided effects of space environment are compensated. Piezoelectric sensors are susceptible to elements of the extreme space environment, such as temperature changes, vacuum, and radiation. Effects of temperature, vacuum, and radiation on piezoelectric sensors were experimentally investigated during electro-mechanical impedance testing in simulated space environment. In this paper, the authors present data from gamma radiation experiments and discuss the possible mechanisms at work in the changes in impedance signatures of the sensors. A theoretical model was used to identify the parameters of the piezoelectric constitutive equations that are affected by gamma radiation exposure. The proposed approach allows for compensating effects associated with space environment and may find utility in design and development of SHM systems for space applications.