Modal Parameter Identification And Damage Detection Study On Space Grid Structure

Engineering modal parameter identification is the important content of health monitoring, fault diagnosis, vibration control and dynamic characteristics. For important health monitoring of large buildings is an important issue much attention. At present, China's construction of large span space structure of the climax to a period of unprecedented growth, the number and scale of its construction are unprecedented in the history. From the development trend of spatial structure, the span will increase. The new structure, advanced technology architecture, to the structural design, calculation and construction have brought great opportunities and challenges. As incidents, earthquakes, wind load and operating load of the role of making large-scale architecture of damage accumulation, and triggered devastating accident. In fact, the structure of the internal damage will inevitably lead to changes in dynamic characteristics, such as the structure of the vibration frequency, damping and mode change. Vibration frequency, damping and mode shapes can be used to identify structural changes in internal damage.The main work and conclusions include:(1) In this paper, the structure of a space truss model of experimental modal analysis, first of all, built on the grid model structure finite element model, and analyze the dynamic characteristics of the model by grid frequency and mode. Then, using the time domain stochastic subspace identification method grid model experimental modal parameter identification, sensors and data acquisition system by the structure of the experimental data obtained, and then post-processing of experimental data. The results show that the theoretical calculations and experimental results agree well.(2) A grid structure damage identification numerical simulation, finite element software to establish the sampling simulation model Reduce the use of unit to simulate the damage area changes, the use of the special nature of grid cells, using the node into a cell strain displacement method, the grid structure of the damage identification. And the strain modal analysis carried out on the network structure of different injuries in the identification, confirmed by first-order relative strain on the effectiveness of structural damage identification.