Smart wireless sensor nodes for structural health monitoring

Because of the low cost, high scalability, and ease of deployment, wireless sensor networks (WSNs) are emerging as a promising sensing paradigm that the structural engineering field has begun to consider as a substitute for traditional tethered structural health monitoring (SHM) systems. For a WSN-based SHM system, particularly the one used for long-term purpose, to provide realtime information about the structure’s healthy status and in the meantime, to avoid high cost of streaming the raw data wirelessly, embedding SHM algorithms within the network is usually necessary. However, unlike other monitoring applications of WSNs, such as environmental and habitat monitoring where embedded algorithms are as simple as average, max, min, etc., many SHM algorithms are centralized and computationally intensive. Implementing SHM algorithms within WSNs hence becomes the main roadblock of many WSN-based SHM systems. This chapter mainly focuses on designing and implementing effective and energy-efficient SHM algorithms in resource-limited WSNs. We first give a summary review of the recent advances of embedding SHM algorithms within WSNs. Then the modal analysis, a classic SHM algorithm widely adopted in SHM, is chosen as an example. How this technique can be embedded within a WSN is described in a step-by-step manner. At last, we propose a WSN-Cloud system architecture, which we believe is a promising paradigm for the future SHM.