Introduction

In the last decades, our energy generation, energy storage, and traveling demands grew enormously. To fulfill these and other needs, more and more complex and sophisticated structures with highly advanced composite materials have been built. Questions arise about the safety and reliability of such equipment for long-term applications. Failure of such structures can have catastrhopic consequences. Therefore, researchers investigate various methods to conduct Structural Health Monitoring to ensure the safe use and longevity of such structures/equipment. Materials designed for high-stress applications emit elastic waves of a specific pattern, traveling in all directions within the structure, under various degradation mechanisms. Piezoelectric materials, owing to their exceptional response to high-frequency, low-amplitude vibrations are perfectly suitable for Structural Health Monitoring.