Session: 17-01-01: Research Posters

Paper Number: 149706

149706 - Advanced Health Monitoring of Composite Structures Using Dense Spray-Coating Active Sensing Arrays 

Guided wave-based structural health monitoring (SHM) technology boasts exceptional economic and strategic merit, as it enhances the safety and operational efficacy of composite structures in critical equipment and structures. The dispersive and multimodal properties of guided waves, coupled with anisotropic propagation behavior in composites, presents a significant challenge for guided wave-based composite SHM techniques. Thus, the selection of sensitive interrogation frequency and wave mode are essential to composite structural damage identification. However, the conventional piezoelectric wafer active sensors require a lot of efforts to be implemented in a dense array format. On the other hand, the low piezoelectric constants and compliant nature of PVDF find difficulty in actuating strong guided waves. Therefore, the development of novel types of dense spray-coating sensing arrays will undoubtedly improve the performance of SHM of composite structures with better actuation/sensing capability as well as strong design adaptability.

This paper proposes a dense spray-coating active sensing arrays for composite structural health monitoring via the guided wave generation and reception. The actuation-sensing capability is realized by integrating piezoelectric nano-powder into a hosting matrix, followed by the formation of an active material layer on the composite surface through a spraying process. The selective actuation and sensing of a certain guided wave mode can be achieved through the optimization of electrode configuration, in conjunction with frequency-wavenumber domain design. This research initiates with the analysis of the dispersion curves of composites so as to determine electrode parameters, including electrode spacing, element width, width-spacing ratio, as well as to determine how these various parameters uniquely affect the guided wave excitation. Subsequently, three-dimensional numerical models in several array patterns, such as interdigited and directional emitting types, are meticulously constructed. Single-mode generation is achieved through the meticulous design of the spatial distribution of array electrodes coupled with wavelength modulations. The electrode configurations are numerically investigated through exciting an anti-symmetric and a symmetric type guided wave mode in a multilayer composite plate. Then, the match between the structural stiffness and acoustic impedance is attained via optimizing the size and ratio of piezoelectric nano-powder particles, as well as the thickness of the coating layer. The optimal guided wave excitation and sensing effects are discerned through pitch-catch experiments. Ultimately, a scanning laser Doppler vibrometer (SLDV) is employed to visualize the waves generated in the structures for analyzing the propagation modes of guided waves in the composite material. The numerical simulations and experimental demonstrations show that the proposed spray-coating sensing arrays system possesses great potential for future composite damage detection applications. The paper finishes with summary, concluding remarks, and suggestions for future work.

Presenting Author: Shulong Zhou Shanghai Jiao Tong University

Presenting Author Biography: He is a Ph.D. candidate from Shanghai Jiao Tong University

Authors:

Shulong Zhou Shanghai Jiao Tong University
Yanfeng Shen Shanghai Jiao Tong University