RESEARCH ON A STRAIN RESPONSE ESTIMATION METHOD FOR TRUSS STRUCTURE FATIGUE MONITORING

Making full use of the information from sensing nodes efficiently is an important and hot research field in structural health monitoring. Due to high maintenance costs and harsh service conditions, structural fatigue monitoring systems tend to have limited measuring points and be difficult to cover vulnerable areas. In this paper, two types of strain response estimation methods, that is, the augmented Kalman filtering and the strain transmissibility matrix are introduced and discussed. Numerical examples and demonstration tests of typical truss structures were conducted to investigate the influencing factors and the practicality of the two methods for fatigue monitoring. The results show that the two methods can effectively estimate the forced vibration responses at a low frequency band under the condition that only one substructure is measurable with a certain extent of measurement noise and modeling error, without having to know the load information or identify the physical parameters. It is noted that the strain transmissibility matrix method can accurately estimate the strain response with simple prior information of the model and fast computation capability without considering the structural damping and mass. Therefore, the strain transmissibility matrix method is more suitable for on-line fatigue monitoring.