Implementation and Validation of a Low-Cost loT-Enabled Shake Table System

Abstract

Shake tables are essential tools for validating structural health monitoring (SHM) systems. However, commercially available shake tables are relatively expensive and often hardly affordable for research and teaching institutions. Moreover, the widespread adoption of remote working and online teaching, fostered by the COVID-19 pandemic, often prevents researchers and students from physically accessing laboratories to conduct experiments. Research and teaching institutions would benefit from using lowcost shake tables with Internet-of-Things (IoT) capabilities for remotely conducting shake table experiments on test structures equipped with SHM systems. This paper presents the implementation and validation of a low-cost IoT-enabled shake table system (IoT-STS). The IoT-STS is composed of off-the-shelf components and builds upon a four-layer architecture. A smartphone application is devised to send periodic or random excitations, i.e. displacement time histories, through an IoT-based cloud service to a microprocessor, which, via actuators, imposes excitations on the shake table. Vice versa, the microprocessor sends the output displacement data, representing the motion reproduced by the shake table, to the cloud for remote access and visualization. To validate the IoT-STS, displacement time histories, remotely entered through the smartphone application, are compared with output displacement data, recorded by a potentiometer. The results demonstrate that the low-cost IoT-STS is capable of accurately imposing periodic and random excitations on test structures, thus showcasing the compatibility of the IoT-STS with remote working and online teaching in light of the COVID-19 pandemic.