Development of a Stamp Size Pulser-Receiver for Structural Health Monitoring Applications

Abstract: SUMMARY This work investigated feasibility of Lamb wave based SHM technique for in-situ monitoring of hidden (inaccessible) web region, for delamination type of defect, in a typical stiffened composite (I-joint) section of an aircraft structure. Finite element model was proposed to understand and compare the wave propagation of fundamental symmetric Lamb mode (S0) through a healthy and center delaminated web of the I-joint. In simulations, S0 mode was excited at the center of web, which then, travels along the web and propagates into skin regions of the I-joint. Turning modes were also observed. From the S0 mode captured at two locations on the skin, one for the direct mode and another for the turning mode, it was seen that amplitude of the captured mode can used as a feature for delamination detection. Experiments were carried out on the I-joint with bonded piezoelectric wafer active sensor patch on the web and skin regions. In order to reduce the weight of the SHM instrumentation, an attempt was made to develop a low footprint, portable instrumentation for actuation, and reception of Lamb waves and wireless live transmission of the ultrasonic data. Experimental measurements showed a similar trend of significant decrease in the amplitude of S0 modes when propagating through the web delamination when compared to simulation. Copyright © 2013 John Wiley & Sons, Ltd.

Abstract: In recent years, many scholars have dedicated their research to the development of low-cost sensors for monitoring of various parameters. Despite their high number of applications, the state of the art related to low-cost sensors in building monitoring has not been addressed. To fill this gap, this article presents a systematic review, following well-established methodology, to analyze the state of the art in two aspects of structural and indoor parameters of buildings, in the SCOPUS database. This analysis allows to illustrate the potential uses of low-cost sensors in the building sector and addresses the scholars the preferred communication protocols and the most common microcontrollers for installation of low-cost monitoring systems. In addition, special attention is paid to describe different areas of the two mentioned fields of building monitoring and the most crucial parameters to be monitored in buildings. Finally, the deficiencies in line with limited number of studies carried out in various fields of building monitoring are overviewed and a series of parameters that ought to be studied in the future are proposed.