Abstract.Compared with riveted and welded joints, bolted joints have advantages of easily dismantled, high load carrying and load-transferring capacity. However, bolted joints are also weaker components of assembled structures. Structural damage detection (SDD) on bolted joints is much required in the field of structural health monitoring (SHM). A new SDD method is proposed for damage identification of structures with bolted joints based on residual error of AR model in time series analysis. Firstly, a new data standardization process is defined to maintain the information of damage location. Then, a new structural damage feature sensitive to structural damage is developed based on the standard deviation of AR model residual errors. To verify the proposed method, a bolted joint structure is designed and fabricated in laboratory, connection damages of structures are simulated by loosening the bolted joints. The acceleration responses of structures with bolted joints under healthy and damage cases are acquired. Finally, the SDD is performed by traditional DSF and the new DSF. The illustrated results show that the proposed method is a hybrid tool for the bolted joint damage detection with the new damage-sensitive feature. In addition, some related issues will be discussed as well.
IntroductionThe vibration-based SDD technique has become an effective way in SDD [1,2]. Normally, SDD can be achieved by comparing the structural characteristics extracted from structural reference state and damage state respectively. Zhou et al [3] used the hierarchical clustering analysis and similarity measure to distinguish structural damage state from health state. Most of these methods can be divided into two categories: model based and feature based. The model based methods need to construct the structural dynamic model. Khatir et al [4] used the co-ordinate modal assurance criterion for SDD. Khatir et al [5] used the modal scale factor and natural frequencies for structural damage detection and localization. To the feature based methods, especially for those based on time series analysis, are found to be less complicated and more sensitive to local damage [6].Most of time series analysis based methods need to construct a time series model that fit for vibration response data and achieves SDD via comparing the extracted features from structural reference (healthy) and damage states. Chen and Yu