Design of a wireless smart sensor node for fatigue assessment of welded joints

Fatigue assessment of welded joints has been a significant way to predict the remaining life of large aging civil engineering structures and provide maintenance guidance for these structures during the past several years. To obtain accurate results, the authentic field-based data from structural health monitoring (SHM) system is usually preferred to be used in the assessment. However, for traditional wired SHM system, the high cost of installing and maintaining wires is restricted to these large structures such as the long-span bridges or tall buildings. This paper focuses on designing a wireless smart sensor node (WSSD) which is promising for estimating the fatigue life of welded joints. The WSSD is designed with high-performance micro-processor, large memory storage, high-precision signal conditioner, etc. The performance of the WSSD is validated using a cantilever beam alongside a wired strain gauge as the reference. During the evaluation, the accuracy, the resolution, the frequency response, and the performance in testing real structure’s response of the WSSD are verified respectively under various excitations applied to the cantilever beam.