In response to the growing global demand for both energy and a clean environment, there has been an unprecedented rise in the utilization of renewable energy. Wind energy plays a crucial role in striving for carbon neutrality due to its eco-friendly characteristics. Despite its significance, wind energy infrastructure is susceptible to damage from various factors including wind or sea waves, rapidly changing environmental conditions, delamination, crack formation, and structural deterioration over time. This research focuses on investigating non-destructive testing (NDT) of wind turbine blades (WTBs) using approaches based on the vibration of the structures. To this end, WTBs are first made from glass fiber-reinforcement polymer (GFRP) using composite molding techniques, and then a short pulse is generated in the structure by a piezoelectric actuator made from lead zirconate titanate (PZT-5H) to generate guided waves. A numerical approach is presented based on solving the elastic time-harmonic wave equations, and a laser Doppler vibrometer (LDV) is utilized to collect the vibrational data in a remote manner, thereby facilitating the crack detection of WTBs. Subsequently, the wave propagation characteristics of intact and damaged structures are analyzed using the Hilbert–Huang transformation (HHT) and fast Fourier transformation (FFT). The results reveal noteworthy distinctions in damaged structures, where the frequency domain exhibits additional components beyond those identified by FFT, and the time domain displays irregularities in proximity to the crack region, as detected by HHT. The results suggest a feasible approach to detecting potential cracks of WTBs in a non-contact and reliable way.

Acoustic wave devices using standing wave configurations have gained interest in various fields like healthcare diagnostics and manufacturing. Their functionalities span from cell sorting to microscale fiber assembly through periodic acoustic pressure fields. Conventional methods usually require parallel acoustic emitters and reflective surfaces, producing constrained standing wave patterns. In this paper, an effective approach for creating versatile acoustic standing wave fields using an acoustic metasurface deflector and retroreflector is introduced. The deflector manipulates the direction of incoming acoustic waves coupled with the retroreflector to reflect these waves back to the source. The proposed design allows the creation of standing waves that are not constrained by the relative angles of the two surfaces involved and allows for customizable wave patterns beyond the standard limits with enhanced adaptability. The system's effectiveness is evaluated through computational simulations using finite element analysis and experimental validation based on a 3D‐printed prototype. Results suggest that versatile standing waves between arbitrarily oriented surfaces can be produced through the careful design of the metasurface deflector and retroreflector. This approach can improve the performance of standing wave applications in particle manipulation, thus broadening the range of practical implementations for ultrasound and acoustofluidic technologies.

The development of advanced robotic systems capable of precise movement without relying on traditional mechanical actuators is a growing area of research. One promising approach involves the use of acoustic waves, where sound waves are used to generate a propulsion force without the use of any moving parts. However, achieving controlled 2D movement in such systems remains a challenge, particularly in terms of efficiency, precision, and scalability. This paper explores the use of 3D‐printed focused acoustic vortex propulsion (FAVP) lenses to drive a miniature robotic swimmer in two dimensions. The principles behind acoustic vortex generation and its application to create both rotational and translational motion on the miniature robot are investigated. The findings demonstrate that a specially designed acoustic lens can focus sound waves to produce localized vortices and streaming forces, which are then harnessed for precise 2D motion control. The robotic swimmer is tested in a variety of controlled environments to validate its ability to perform complex maneuvers, such as forward motion, rotational control, and directional steering. This research highlights the potential of acoustic vortex propulsion as a viable solution for non‐contact, high‐precision movement in small‐scale robots, with profound implications in fields such as micro‐robotics and underwater exploration.