An <italic>In-Situ</italic> Structural Health Diagnosis Technique and Its Realization via a Modularized System

Abstract

By scrutinizing local propagation characteristics of damage-modulated guided waves (GWs), an in-situ health diagnosis technique, targeting in-service engineering structures, is developed. This technique characterizes structural damage quantitatively, regardless of its quantity, and consequently evaluates structural integrity in a real-time manner. A self-contained system is accordingly configured to materialize this technique, which integrates modularized components through a bus called Peripheral component interconnect eXtensions for Instrumentation (PXI), for active GW generation, multichannel data acquisition, central control, signal postprocessing, and results presentation. The monitoring results are presented in pixelated images by virtue of a diagnostic imaging algorithm, facilitating comprehension of the overall structural health status intuitively, promptly, and automatically. In conjunction with the system, a sensing technique, based on a concept of decentralized standard sensing, is demonstrated, which has a capacity of constructing a sensor network with convenience and flexibility. An optimal benchmarking strategy in accordance with signal correlation is formulated to compensate for the adverse ambient influence (e.g., temperature fluctuation) in rugged measurement conditions. Experimental validation is carried out to verify the technique and the system by evaluating mock-up damage in planar and tubular structures quantitatively, showing superior detectability, sensitivity, and accuracy. Notably, its expandable nature allows the system to be tailor-made toward diverse real-world applications, and enhances the universality, flexibility, and compatibility of the developed diagnosis technique.