Bolt looseness detection using Spectral Kurtosis analysis for structural health monitoring

Abstract

Bolt looseness is a major problem for high valued infrastructure assets such as bridges. Historical data indicates failure in the operating bridges is related to bolted joints. This reveals defects generated by small components can leads to major problem thus early detection is required. In this paper, a novel methodology to characterize the bolt looseness using optimal filtering of vibration data is proposed. A Spectral Kurtosis (SK) based optimal filter is designed to extract frequencies that are generated by bolt looseness. The filter is capable of extracting weak signatures (hidden in acceleration data) that are generated by bolt looseness. The proposed approach is demonstrated through experiments. Results have indicated that the proposed approach can be reliable and effective in detecting loose bolts of a structure subjected to fluctuating loads.