Damage Detection Of Bridge Subjected To A Moving Load Based On HHT And Reconstructed Phase Space

As the development of the society and the progress of technology, modern structures aredeveloping rapidly and becoming more and more complex and large. However its complexservice environments of service lead to potential threat to the safety of the structure. Once thelarge structure collapse, it may lead to catastrophic failures causing costly repair or heavy lossof human lives. Therefore, the structure damage identification and health monitoring hasbecome a hot research topic.Traditional modal-based methods have many disadvantages such as much more numberof measurement points, lower identification accuracy, and lower robustness to noise. In thispaper, according to the current problems and challenges of structural damage detection andhealth monitoring, two novel damage detection methods based on traveling load is introduced.By combining theoretical derivation and numerical simulation research method, thesuperiority of damage detection method based on reconstructed phase space andHilbert-Huang transform (HHT) is analyzed. The method proposed in this paper can solvethese problems effectively. The main work of this paper consists of the following aspects:1. Firstly, the significance of this research field is introduced. Based on the analysis ofcurrent research situation of this field in the world, current problems, difficulties andchallenges in the application of real engineering structures are summarized. Thereafter, thecurrent research situation of HHT and reconstructed phase space is discussed, which includesdeficiency of these ways and advantages of these methods based on traveling load.2. In the theoretical section, the HHT method is introduced and applied to a simplysupported Euler-Bernoulli beam and the analytical solution is also discussed. The selection ofdelay time and embedding dimension of reconstructed phase space in reconstructed phasespace method is also introduced. The results indicate that these techniques using a single pointmeasurement are able to identify the existence and the location of the damage along the beam.3. The responses of a simple beam under different damage scenarios are measured by asingle measurement point in the middle of the beam in the simulate section. The identificationcapabilities of the proposed techniques are studied by varying the damage locations, crackdepths and velocity of the moving load etc. The ANSYS model of Hai Zhu bridge with the ratio for1:10is also studied. The results indicate that these methods can successfully identifythe damage of simple supported beam, as well as a complex steel structure, through a singlepoint, which indicates that these methods are feasible and reliable. The qualitative comparisonof the mentioned methods indicates the phase space reconstruction method can be moreefficient, more stable during identification of damage. Preliminary experiment research of HaiZhu bridge model shows that damage position can be identified through maximal value ofthese two methods. But the sensitivity declines in both methods compared with the simulatesection. The identification regulations influenced by the moving load velocity, amplitude, et al,are as the same in simulation.